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1
Jia, Jingyi. "Strontium -90 Radiation Detection." Thesis, Mittuniversitetet, Avdelningen för elektronikkonstruktion, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-23308.
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The objective of this thesis is to construct a measurement system, measuring Radiation from Strontium with mass number 90 ( 90 Sr). The absorbed beta particle has a kinetic energy of 546 keV. The constructed scanning system makes it possible to sweep over a larger area than the actual Silicon detector. The used detector has an area of 1cm 2 . [1] A Si detector is connected to an electronic read out circuit. The Arduino microcontroller reads the output of the circuit and translates it to digital signals and sends them to a personal computer. After one signal has been read, Arduino will discharge the peak detector in the circuit to read another signal. The Arduino control software Processing will receive and process the digital output from Arduino. There will be three windows showing the number of counts from Arduino, the movement of the steering engine controlled by Thorlabs, and the sum counts of every position where the detector is.
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Wang, Jinghui. "Evaluation of GaN as a Radiation Detection Material." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1343316898.
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Matlack, Kathryn H. "Nonlinear ultrasound for radiation damage detection." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51965.
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Radiation damage occurs in reactor pressure vessel (RPV) steel, causing microstructural changes such as point defect clusters, interstitial loops, vacancy-solute clusters, and precipitates, that cause material embrittlement. Radiation damage is a crucial concern in the nuclear industry since many nuclear plants throughout the US are entering the first period of life extension and older plants are currently undergoing assessment of technical basis to operate beyond 60 years. The result of extended operation is that the RPV and other components will be exposed to higher levels of neutron radiation than they were originally designed to withstand. There is currently no nondestructive evaluation technique that can unambiguously assess the amount of radiation damage in RPV steels. Nonlinear ultrasound (NLU) is a nondestructive evaluation technique that is sensitive to microstructural features such as dislocations, precipitates, and their interactions in metallic materials. The physical effect monitored by NLU is the generation of higher harmonic frequencies in an initially monochromatic ultrasonic wave, arising from the interaction of the ultrasonic wave with microstructural features. This effect is quantified with the measurable acoustic nonlinearity parameter, beta. In this work, nonlinear ultrasound is used to characterize radiation damage in reactor pressure vessel steels over a range of fluence levels, irradiation temperatures, and material composition. Experimental results are presented and interpreted with newly developed analytical models that combine different irradiation-induced microstructural contributions to the acoustic nonlinearity parameter.
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Fronk, Ryan G. "Dual-side etched microstructured semiconductor neutron detectors." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/35426.
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Doctor of PhilosophyDepartment of Mechanical and Nuclear Engineering
Douglas S. McGregor
Interest in high-efficiency replacements for thin-film-coated thermal neutron detectors led to the development of single-sided microstructured semiconductor neutron detectors (MSNDs). MSNDs are designed with micro-sized trench structures that are etched into a vertically-oriented pvn-junction diode, and backfilled with a neutron converting material, such as ⁶LiF. Neutrons absorbed by the converting material produce a pair of charged-particle reaction products that can be measured by the diode substrate. MSNDs have higher neutron-absorption and reaction-product counting efficiencies than their thin-film-coated counterparts, resulting in up to a 10x increase in intrinsic thermal neutron detection efficiency. The detection efficiency for a single-sided MSND is reduced by neutron streaming paths between the conversion-material filled regions that consequently allow neutrons to pass undetected through the detector. Previously, the highest reported intrinsic thermal neutron detection efficiency for a single MSND was approximately 30%. Methods for double-stacking and aligning MSNDs to reduce neutron streaming produced devices with an intrinsic thermal neutron detection efficiency of 42%. Presented here is a new type of MSND that features a complementary second set of trenches that are etched into the back-side of the detector substrate. These dual-sided microstructured semiconductor neutron detectors (DS-MSNDs) have the ability to absorb and detect neutrons that stream through the front-side, effectively doubling the detection efficiency of a single-sided device. DS-MSND sensors are theoretically capable of achieving greater than 80% intrinsic thermal neutron detection efficiency for a 1-mm thick device. Prototype DS-MSNDs with diffused pvp-junction operated at 0-V applied bias have achieved 53.54±0.61%, exceeding that of the single-sided MSNDs and double-stacked MSNDs to represent a new record for detection efficiency for such solid-state devices.
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Jabor, Abbas. "Novelty and change detection radiation physics experiments." Licentiate thesis, Stockholm : Fysiska institutionen, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4410.
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Blue, Andrew James. "New materials & processes for radiation detection." Thesis, University of Glasgow, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412938.
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Mahon, Alexandra Rose. "Ultraviolet absorption detection of DNA in gels." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298204.
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George, Tyrel Daniel Frank. "Design and testing of long-lifetime active sensor arrays for in-core multi-dimensional flux measurements." Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/35229.
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Master of ScienceDepartment of Mechanical and Nuclear Engineering
Douglas S. McGregor
Fission chambers are a common type of detector used to determine the neutron flux and power of a nuclear reactor. Due to the limited space and high neutron flux in a reactor core, it is difficult to perform real-time flux measurements with present-day in-core instrumentation. Micro-pocket fission detectors, or MPFDs, are relatively small in size and have low neutron sensitivity while retaining a large neutron to gamma ray discrimination ratio, thereby, allowing them to be used as active neutron flux monitors inside a nuclear reactor core. The micro-pocket fission chamber allows for multiple detectors to be inserted into a flux port or other available openings within the nuclear reactor core. Any material used to construct the MPFD must be rugged and capable of sustaining radiation damage for long periods of time. Each calibrated MPFD provides measurements of the flux for a discrete location. The size of these detectors allows for a spatial map of the flux to be developed, enabling real-time analysis of core burnup, power peaking, and rod shadowing. Small diameter thermocouples can be included with the array to also measure the temperature at each location. The following document details the research and development of MPFDs for long term use in nuclear power reactors. Previous MPFD designs were improved, miniaturized, and optimized for long term operations in reactor test ports designed for passive measurements of fluence using iron wires. Detector chambers with dimensions of 0.08 in x 0.06 in x 0.04 in were attached to a common cathode and individual anodes to construct an array of the MPFDs. Each array was tested at the Kansas State University TRIGA Mark II nuclear reactor to demonstrate functionality. The linear response in reactor power was measured. These arrays have also demonstrated reactor power tracking by following reactivity changes in steady state operations and reactor pulsing events. Stability testing showed consistent operation at 100 kW for several hours. The MPFDs have been demonstrated to be a viable technology for in-core measurements.
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Boardman, Robert James. "The detection of Cerenkov radiation from neutrino interactions." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315715.
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Philip, Axel. "Theoretical Foundations and Experimental Detection of Gravitational Radiation." Thesis, KTH, Skolan för teknikvetenskap (SCI), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-215078.
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Gravitational waves emerge as a prediction of Einstein’s theory of general relativity. On account of the recent detection, by the LIGO scientific collaboration, this thesis offers a brief review of the fundamentals of gravitational wave theory, and of the challenges involved in direct experimental detection. Existensen av gravitationsvågor är en förutsägelse av Einsteins allmänna relativitetsteori. Med anledning av att de nyligen upptäckts, utav det vetenskapliga samarbetsprojektet LIGO, erbjuder denna avhandling en genomgång av grunderna till teorin om gravitationsvågor, och av svårigheterna inför att upptäcka dem experimentellt.
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Gooda, P. H. "Evaluation of silicon photodiodes for detection of ionising radiation." Thesis, University of Surrey, 1988. http://epubs.surrey.ac.uk/844379/.
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The main objective of this research project was to investigate the suitability of the silicon photodiode as a light sensor for scintillation detection of ionising radiation. The type of instrument originally envisaged by Fisher would be particularly applicable to measurement of gamma-ray dose rates. During the course of the research, it was found that some modern silicon photodiodes are very effective as direct semiconductor detectors for both charged particles, and also for photons in the energy range 8 - 140 keV. A summary of this section of the work was published (GOODA and GILBOY, 1987) and has generated considerable interest in the subject. An associated medical physics project in Denmark was developed on the basis of these observations. The development of the photodiode as a scintillation light detector also proved highly successful. Using a CsI(Tl) scintillator and commercially available photodiodes, pulse height energy spectra rivalling those obtainable from conventional photomultiplier-NaI(Tl) assemblies were achieved. By comparing scintillation pulses with direct gamma absorption events in the photodiode, the light output of CsI(Tl) was determined to be significantly higher than that of NaI(Tl), which is usually accepted as the most efficient scintillator at room temperature. The detector assembly developed was successfully employed in the acquisition of data for a gamma ray transmission computer tomography system. A gamma dose rate instrument based on the CsI(Tl)-photodiode combination is also clearly feasible, but more work needs to be done to ascertain the range and sensitivity of this device. In addition to the developmental side of the project, some investigations were made into scintillation pulse shapes induced by gamma rays and alpha particles in CsI(Tl), with particular attention paid to afterglow. The Bollinger-Thomas method employed was modified by the inclusion of a spectrophotometer to investigate the wavelength dependence of pulse shapes.
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Li, Sinan. "Laser speckle contrast detection of acoustic radiation force response." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/34931.
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Light and ultrasound are both non-ionizing radiations, ideal for biomedical applications. Recent studies on combining ultrasound and light for biomedical imaging show new promises in improving imaging quality and/or providing complementary imaging contrast. Among a variety of the imaging modalities that simultaneously use ultrasound and light, this work focuses on optical detection of tissue responses to acoustic radiation force (ARF). The applications include optical shear wave elastography and ultrasound modulated optical tomography. The first half of the thesis provides a systematic study on tracking shear waves in optical turbid media using CCD-based laser speckle contrast analysis. The theory, simulation and experiment are developed and cross-validated. The simulation quantitatively relates CCD speckle contrast signal with shear waves, providing useful information to understand the underlying physics. In addition, multiple shear waves are tracked using laser speckle contrast detection. Results show that two counter-propagating shear waves produce a modulation pattern in the optical signal, and the modulation pattern was suggested by simulation as a result of the dual shear wave interference. Shear wave speed measurements in phantoms suggest that the dual shear wave approach is more accurate than the single shear wave approach as that the standard deviation of the speed measurement is reduced by a factor of at least 2. The the dual shear wave approach also provides a reduced boundary effect. Both factors suggest that the dual shear wave approach should improve the accuracy of elasticity measurements. In the second half of the thesis, instead of detecting ARF response in the late phase, the study is motivated by detecting ARF response in the early stage for enhancement of ultrasound modulation of light. A pilot study on incorporating perfluorocarbon-based phase change contrast agent with ultrasound modulated optical tomography is explored. To understand the phase transition process, a quantitative measurement of acoustic nanodroplet vapourisation is developed. A preliminary result also showed that a single ultrasound burst can simultaneously vaporise the nanodroplets and sonify the converted microbubbles to provide additional ultrasound modulation of light. This additional light modulation was shown to increase the laser speckle contrast signal detected on a CCD camera.
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Fullem, Travis Z. "Radiation detection using single event upsets in memory chips." Diss., Online access via UMI:, 2006.
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Fung, Y. W. F. "The synthesis of novel organic materials for radiation detection." Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.599266.
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The aim of the project is to synthesise organic materials to allow for efficient and reproducible quantification of radiation doses. The measurement should be simple, and be able to be read out immediately. In one approach, highly fluorescent organic materials, especially conjugated materials, would be used as radiation detectors. The polymer films will be designed to produce quenching centres upon irradiation; therefore the loss of fluorescence will give an accurate measurement of the total radiation dose received. Another method is to measure the conductivity of the material before and after radiation exposure. A sensitiser or radiaolabile dopant to enhance response may also be necessary. Here, iodine-containing compounds and onium salts were used. Iodine-containing compounds are expected to produce iodine upon irradiation. Onium salts are used as photoinitiators for polymerisations, producing acid species upon irradiation. Both acids and iodine can then act as dopants for conjugated polymers, resulting in quenching of fluorescence and increases in conductivity. A wide variety of materials were synthesised for evaluation. These included iodinated conjugated polymers, sulphonium and iodonium salts. A novel fluorescent diacetylene was also synthesised as well as several known polymers such as MEH-PPV, PHT and poly(3-BCMU). The effects of visible light on these materials, as well as blends were looked at, and some novel effects found. In particular, the photosensitisation and subsequent doping of MEH-PPV with onium salts was discovered.
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Thirimanne, Hashini. "'Inorganics-in-organics' semiconductors for high energy radiation detection." Thesis, University of Surrey, 2019. http://epubs.surrey.ac.uk/850053/.
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X-ray detectors are an invaluable tool for healthcare diagnostics, cancer therapy, homeland security and non-destructive evaluation among many fields. However, potential uses for X-rays are limited by system cost and/or detector dimensions. Current X-ray detector sensitivities are limited by the bulk X-ray attenuation of the materials and consequently necessitates thick crystals with dimensions of ~ 1 mm - 1 cm, resulting in rigid structure, high operational voltages and high cost. Semiconducting polymer X-ray detectors are an emerging low cost technology. Their solution processable nature enables the fabrication of such detectors on flexible substrates over large areas using printing and roll-to-roll coating techniques. However, the low atomic number (Z) of organic materials results in low X-ray attenuation and hence, low X-ray sensitivities. This thesis focuses on direct detection of X-rays using organic semiconducting systems incorporating high Z Bi2O3 nanoparticles (NPs). For the work discussed, a thick organic bulk heterojunction (~10 - 20 μm) consisting of the p-type poly(3-hexylthiophene-2,5-diyl) (P3HT) and the n type [6,6]-Phenyl C71 butyric acid methyl ester (PC70BM) are utilised. The effectiveness on the utilisation of a dual carrier system is demonstrated through the fabrication of detectors in a diode architecture by varying the NP loading from 0 - ~50% (by wt.). These hybrid detectors demonstrate sensitivities of 1712 μC mGy-1 cm-3 when irradiated under 50 kV tungsten X-ray source and ~30 and 58 μC mGy-1 cm-3 under 6 and 15 MV X-rays generated from a medical linear accelerator. A flexible detector was fabricated which demonstrated a high sensitivity approaching 300 μC mGy-1 cm-3, highlighting the promise of the technology for dosimetry and imaging in non-planar architectures. These performances are discussed based on the structural and electrical characteristics of the hybrid thick film diodes. Possible mechanisms for the high sensitivity observed are proposed where photoconducting gain, impact ionisation and Mie scattering are identified as central contributors towards the detector sensitivity. Routes to increasing the detector thickness to 100 μm - 1 mm thickness range is demonstrated using a pellet based on powder sintering technique. These P3HT:PC70BM:Bi2O3 detectors operate as photoconductors showing X-ray sensitivities in the region of ~ 160 C mGy-1 cm-3 and a preliminary X-ray imager based on the pellets are fabricated. Finally, potential routes for further improvement of the detector characteristics are discussed.
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Baas, Larry Brandon. "Feasibility Study of Concept Designs for Photonic Radiation Detection." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1245376171.
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Wang, Jinghui. "Fabrication, Characterization and Simulation of Sandwich Structure GaN Schottky Diode Ionizing Radiation Detectors." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1405497243.
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Brooks, Michael David. "Fast neutron dosimetry employing soft error detection in dynamic random access memories." Thesis, London South Bank University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245095.
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Ali, Mohammad Hanif. "Study of soft errors in dynamic random access memories for neutron dosimetry." Thesis, London South Bank University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357203.
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Duckworth, A. "Detection of species by laser resonant spectroscopy." Thesis, Open University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234733.
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Lachane, Martin. "Portal imaging with a direct-detection active matrix flat panel imager." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=38070.
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The problem of charge creation by x-rays in amorphous selenium (a-Se) is studied. A quantitative theory is developed which includes collective and single electron-hole pair excitations by a passing electron. This theory is incorporated into a Monte Carlo code to calculate track structures in a-Se. The initial positions of the electron-hole pairs along these tracks are used to study the fraction of pairs which recombine versus incident x-ray energy and applied electric field. The experimentally-observed energy dependence of recombination is attributed to a spur size which is dependent on the velocity of the ionizing electrons. The theory and simulations agree with available experimental data in the energy range from 20 keV to 10 MeV.The use of an a-Se based direct-detection active matrix flat-panel imager (AMFPI) is explored at megavoltage energies for use in the verification of radiotherapy treatments. As with most other megavoltage detectors, a metal front plate is used to reduce patient scatter and to act as a buildup layer. The Modulation Transfer Function (MTF), Noise Power Spectrum (NPS), and Detective Quantum Efficiency (DQE) are measured. The DQE for the direct detection AMFPI is compared with the published DQE of an indirect detection AMFPI for portal imaging. The direct detector has a lower DQE at zero frequency, but there is a cross-over at approximately 0.3 cycles/mm after which it has a higher DQE.
A theoretical expression for the DQE of medical imaging detectors with non-elementary cascade stages is derived. This formalism can be used in conjunction with Monte Carlo techniques to evaluate the DQE of megavoltage imaging detectors. The predictions of the theory agree with the experimental DQE results for the direct-detection AMFPI and also for published results for the DQE of both a metal/phosphor detector and an indirect-detection AMFPI.
The effect of scatter on image quality is modeled in terms of the scatter fraction (SF) and scatter-to-primary ratio (SPR) using Monte Carlo techniques. To validate these simulations, the SF is measured experimentally using a prototype a-Se detector which uses an electrostatic probe to measure the a-Se surface potential. The simulations are used, along with the DQE simulations, to study the effect of metal/a-Se or metal/phosphor thicknesses on image quality in direct and indirect AMFPIs at megavoltage energies. It is found that for a-Se or phosphor thicknesses less than about 300 mum, a front plate of about 1 mm copper is optimal whereas for larger a-Se/phosphor thicknesses a front plate of about 0.4 mm may in some situations lead to better image quality.
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JAFFE, DEBORAH RUTH. "MOUSE SKIN TUMOR INITIATION BY IONIZING RADIATION AND THE DETECTION OF DOMINANT TRANSFORMING GENE(S)." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184146.
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The initiating potential of a range of 4 MeV X-rays was studied using the mouse skin two-stage model of carcinogenesis. A single dose of radiation was followed by promotion with 12-O-tetradecanoyl phorbol-13-acetate (TPA). The effect of TPA on tumor incidence when applied as a single dose 24 hours prior to irradiation was examined. Studies were also designed to investigate the effect of promotion duration on tumor incidence. Animals were promoted with TPA for 10 or 60 weeks. Evidence presented here indicates that ionizing radiation can act as an initiator in this model system. All animals that were promoted with TPA for the same duration had a similar incidence of papillomas (pap) regardless of radiation or TPA pretreatment. However, squamous cell carcinomas (scc) arose only in animals that were initiated with ionizing radiation followed by TPA promotion. Increasing the promotion duration enhanced the incidence of scc at the lower initiation dose. TPA pretreatment at the higher irradiation dose resulted in an overall decrease in tumor incidence. At the lower dose of radiation, TPA pretreatment resulted in an increase in the incidence of scc. The incidence of basal cell carcinomas (bcc) was dose dependent and appeared to be independent of TPA promotion. Although ionizing radiation acts as a weak initiator in mouse skin, the conversion of pap to scc was higher than that reported for chemical initiators. To test this further animals were initiated with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) followed by biweekly promotion with TPA. After 20 weeks of promotion, the animals were treated with either acetone, TPA or 8 fractions of 1 MeV electrons. Data indicate that the dose and fractionation protocol used in this study enhanced the progression of pre-existing pap. To examine the role of oncogene activation in radiation induced mouse skin tumors, DNA from various tumors (pap, bcc, scc) were examined for the presence of dominant transforming activity by the NIH3T3 and Rat-2 focus assays. Dominant transforming activity was observed in all tumor types but not in normal or treated epidermis or corresponding liver. The transformed phenotype was further confirmed by growth in soft agar and tumorigenicity in Nude mice. Southern blot hybridization to ras (Ha, Ki, N), raf, neu, erbB and β-lym indicate that these genes are not responsible for the observed transforming activity. These data suggest that the oncogenic sequences activated in these tumors are unique. The work presented here also provides evidence for novel c-myc transcripts and corresponding genomic rearrangements in a few of the tumors studied.
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Urmi, Nusrat Jahan. "Cryptosporidium capture and detection of ultraviolet radiation induced DNA damage." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/61058.
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Majority of the waterborne outbreaks in USA and Canada are associated with protozoa. Cryptosporidium, an obligate intra-cellular human pathogen, is responsible for more than 50% of these outbreaks and has become one of the major public health concerns as they can survive typical chemical disinfection treatments. Early detection of this parasite in the water and determination of ultraviolet treatment efficacy can play a role in reducing this disease burden.
An antibody based capture surface was developed to detect Cryptosporidium oocysts in treated water. The surface was able to capture three different species of Cryptosporidium: C. parvum; C. muris; C. hominis but not E. coli indicating that the capture surface is Cryptosporidium genus specific rather than species specific and the chances of capturing microorganisms other than Cryptosporidium from water are low. IgG3 was selected as better candidate for the capture surface development due to its higher capture efficiency (~84%-90%) compared to that of IgG1 (~54%-74%). Though the oocysts were successfully released in intact form from the capture surface at pH 1.0, it was not possible to reuse the surface because the capture performance decreased after pH treatment.
An indirect ELISA protocol was optimized to detect UV induced photoproducts (CPDs) in the DNA of UV treated Cryptosporidium oocysts using cuvettes in a spectrophotometer. Power soil kit was selected as the preferred DNA extraction kit because of its high recovery from low concentration of Cryptosporidium in water with high concentrations of other solids. The optimized ELISA protocol was applied on the samples spiked with different doses (0, 3, 6, 10 and 40 mJ/cm²) of UV irradiated Cryptosporidium oocysts. The signal generated from DNA-antibody reaction resulted in an exponential rise to maximum curve which showed that the absorbance (indication of DNA damage) increased with the increase in UV dose. Adaptation of these techniques for Cryptosporidium detection & UV treatment validation is expected to improve the standards for water quality monitoring, providing the communities with assurance that their water is safe to consume.Irving K. Barber School of Arts and Sciences (Okanagan)
Biology, Department of (Okanagan)
Graduate
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Santana-Corte, Juan Martin. "GaAs diodes in the relaxation regime used for radiation detection." Thesis, Lancaster University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387434.
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Hossain, Mainul. "X-ray Radiation Enabled Cancer Detection and Treatment with Nanoparticles." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5309.
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Despite significant improvements in medical sciences over the last decade, cancer still continues to be a major cause of death in humans throughout the world. Parallel to the efforts of understanding the intricacies of cancer biology, researchers are continuously striving to develop effective cancer detection and treatment strategies. Use of nanotechnology in the modern era opens up a wide range of possibilities for diagnostics, therapies and preventive measures for cancer management. Although, existing strategies of cancer detection and treatment, using nanoparticles, have been proven successful in case of cancer imaging and targeted drug deliveries, they are often limited by poor sensitivity, lack of specificity, complex sample preparation efforts and inherent toxicities associated with the nanoparticles, especially in case of in-vivo applications. Moreover, the detection of cancer is not necessarily integrated with treatment. X-rays have long been used in radiation therapy to kill cancer cells and also for imaging tumors inside the body using nanoparticles as contrast agents. However, X-rays, in combination with nanoparticles, can also be used for cancer diagnosis by detecting cancer biomarkers and circulating tumor cells. Moreover, the use of nanoparticles can also enhance the efficacy of X-ray radiation therapy for cancer treatment. This dissertation describes a novel in vitro technique for cancer detection and treatment using X-ray radiation and nanoparticles. Surfaces of synthesized metallic nanoparticles have been modified with appropriate ligands to specifically target cancer cells and biomarkers in vitro. Characteristic X-ray fluorescence signals from the X-ray irradiated nanoparticles are then used for detecting the presence of cancer. The method enables simultaneous detection of multiple cancer biomarkers allowing accurate diagnosis and early detection of cancer. Circulating tumor cells, which are the primary indicators of cancer metastasis, have also been detected where the use of magnetic nanoparticles allows enrichment of rare cancer cells prior to detection. The approach is unique in that it integrates cancer detection and treatment under one platform, since, X-rays have been shown to effectively kill cancer cells through radiation induced DNA damage. Due to high penetrating power of X-rays, the method has potential applications for in vivo detection and treatment of deeply buried cancers in humans. The effect of nanoparticle toxicity on multiple cell types has been investigated using conventional cytotoxicity assays for both unmodified nanoparticles as well as nanoparticles modified with a variety of surface coatings. Appropriate surface modifications have significantly reduced inherent toxicity of nanoparticles, providing possibilities for future clinical applications. To investigate cellular damages caused by X-ray radiation, an on-chip biodosimeter has been fabricated based on three dimensional microtissues which allows direct monitoring of responses to X-ray exposure for multiple mammalian cell types. Damage to tumor cells caused by X-rays is known to be significantly higher in presence of nanoparticles which act as radiosensitizers and enhance localized radiation doses. An analytical approach is used to investigate the various parameters that affect the radiosensitizing properties of the nanoparticles. The results can be used to increase the efficacy of nanoparticle aided X-ray radiation therapy for cancer treatment by appropriate choice of X-ray beam energy, nanoparticle size, material composition and location of nanoparticle with respect to the tumor cell nucleus.Ph.D.
Doctorate
Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering
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Sandberg, Hampus. "Radiation Hardened System Design with Mitigation and Detection in FPGA." Thesis, Linköpings universitet, Datorteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-132942.
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FPGAs are attractive devices as they enable the designer to make changes to the system during its lifetime. This is important in the early stages of development when all the details of the final system might not be known yet. In a research environment like at CERN there are many FPGAs used for this very reason and also because they enable high speed communication and processing. The biggest problem at CERN is that the systems might have to operate in a radioactive envi- ronment which is very harsh on electronics. ASICs can be designed to withstand high levels of radiation and are used in many places but they are expensive in terms of cost and time and they are not very flexible. There is therefore a need to understand if it is possible to use FPGAs in these places or what needs to be done to make it possible. Mitigation techniques can be used to avoid that a fault caused by radiation is disrupting the system. How this can be done and the importance of under- standing the underlying architecture of the FPGA is discussed in this thesis. A simulation tool used for injecting faults into the design is proposed in order to verify that the techniques used are working as expected which might not always be the case. The methods used during simulation which provided the best protec- tion against faults is added to a system design which is implemented on a flash based FPGA mounted on a board. This board was installed in the CERN Proton Synchrotron for 99 days during which the system was continuously monitored. During this time 11 faults were detected and the system was still functional at the end of the test. The result from the simulation and hardware test shows that with reasonable effort it is possible to use commercially available FPGAs in a radioactive environment.
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Koziel, Michal. "Development of radiation hardened pixel sensors for charged particle detection." Strasbourg, 2011. http://www.theses.fr/2011STRA6237.
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Les capteurs CMOS sont développés depuis une décennie en vue d’équiper les détecteurs de vertex des expériences de physique des particules à venir, avec les avantages d’un faible budget de matière et de bas coûts de production. Les caractéristiques recherchées sont un temps de lecture court, une granularité élevée et une bonne radiorésistance. Cette thèse est principalement consacrée à l’optimisation de ce dernier point. Pour diminuer le temps de cycle vers les 10 microsecondes, la lecture des pixels en parallèle dans chaque colonne a été implémentée, associée à une logique de suppression d’information des pixels sans signal. Les pixels sont devenus plus complexes et plus sensibles aux rayonnements ionisants. L’optimisation de l’architecture des pixels, par des techniques standard de durcissement aux rayonnements, a porté la limite à 300 krad (quelques Mrad attendus) pour le procédé de fabrication à 0,35-um utilisé jusque-là. L’amélioration de la tenue aux rayonnements ionisants passe par l’utilisation de technologies de taille inférieure à 0,35-um, naturellement plus radio-résistantes. Ceci facilitant de plus l’intégration de tous les composants dans un pixel. Un autre aspect abordé dans cette thèse concerne la tolérance aux rayonnements non ionisants. Différentes technologies CMOS améliorant la collecte de charges ont été testées. L’utilisation d’une couche de détection de haute résistivité a porté la tenue à ces rayonnements à 3•1013 neq/cm2, conforme à l’objectif fixé. Ce résultat marque une étape importante pour les capteurs CMOS qui devraient rapidement satisfaire le cahier des charges d’expériences particulièrement contraignantes telles que CBM par exempleCMOS Pixel Sensors are being developed since a few years to equip vertex detectors for future high-energy physics experiments with the crucial advantages of a low material budget and low production costs. The features simultaneously required are a short readout time, high granularity and high tolerance to radiation. This thesis mainly focuses on the radiation tolerance studies. To achieve the targeted readout time (tens of microseconds), the sensor pixel readout was organized in parallel columns restricting in addition the readout to pixels that had collected the signal charge. The pixels became then more complex, and consequently more sensitive to radiation. Different in-pixel architectures were studied and it was concluded that the tolerance to ionizing radiation was limited to 300 krad with the 0. 35-um fabrication process currently used, while the targeted value was several Mrad. Improving this situation calls for implementation of the sensors in processes with a smaller feature size which naturally improve the radiation tolerance while simultaneously accommodate all the in-pixel microcircuitry in small pixels. Another aspect addressed in this thesis was the tolerance to non ionizing radiation, with a targeted value of >1013 neq/cm2. Different CMOS technologies featuring an enhanced signal collection were therefore investigated. It was demonstrated that this tolerance could be improved to 3•1013 neq/cm2 by the means of a high-resistivity epitaxial layer. This achievement triggered a new age of the CMOS pixel sensors and showed that their development is on a good track to meet the requirements of the particularly demanding CBM experiment
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COVA, FRANCESCA. "Rare-Earth doped Scintillating Silica Fibers for ionizing radiation detection." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2020. http://hdl.handle.net/10281/263105.
Full textAbstract:
I materiali con proprietà di scintillazione trovano ampio impiego in applicazioni che riguardano la rivelazione di radiazioni ionizzanti, quali il monitoraggio e la diagnostica per immagini, la dosimetria in campo medico, la sicurezza nazionale ed industriale, e la fisica delle alte energie.
Recentemente, la scoperta di nuovi scintillatori veloci ed efficienti ha rappresentato un campo di ricerca in attivo e continuo sviluppo. Fra i numerosi sistemi indagati, le fibre ottiche scintillanti hanno suscitato grande interesse grazie alla loro estrema versatilità che permette la progettazione di rivelatori con un design innovativo.
In questa tesi si propone lo studio di fibre scintillanti di silice che mostrano efficienti proprietà luminescenti quando drogate con ioni di terre rare, come Cerio e Praseodimio.
L’argomento è trattato sia da un punto di vista fondamentale che applicativo, al fine di migliorare ed ottimizzare la resa del materiale perché possa essere impiegato in rivelatori di nuova generazione.
A questo scopo, si è deciso di studiare gli effetti dell’esposizione ad elevate dosi di radiazioni ionizzanti sulla trasparenza del materiale.
L’ottimizzazione della concentrazione del drogante luminescente nella matrice di silice, nonché dei processi di sintesi sol-gel e di filatura della fibra ha permesso di ottenere un’efficiente propagazione della luce all’interno della fibra stessa. É stata altresì dimostrata la fattibilità di una rivelazione simultanea di luce Cherenkov e di scintillazione, esponendo a fasci di elettroni altamente energetici un piccolo prototipo di calorimetro realizzato con fibre scintillanti drogate con Cerio. Le fibre di silice possono quindi essere considerate promettenti candidate in quell’ambito della calorimetria che prevede l’utilizzo della doppia lettura del segnale Cherenkov e di scintillazione per compensare le fluttuazioni energetiche caratteristiche dell’interazione con adroni pesanti.
Inoltre, una completa conoscenza dei fattori che limitano l’efficienza di scintillazione è di primaria importanza per una futura ingegnerizzazione del materiale: l’esistenza di difetti di punto, che competono con i centri luminescenti nella cattura dei portatori di carica generati a seguito dell’interazione con la radiazione ionizzante, risulta essere la principale causa della presenza di una componente temporale lenta nella cinetica di ricombinazione. É stato quindi condotto uno studio approfondito del ruolo dei difetti nelle fibre di silice, al fine di comprenderne la natura e gli effetti sulle proprietà di scintillazione.
I risultati ottenuti in questa tesi hanno confermato il potenziale di questa tecnologia per applicazioni in rivelatori per fisica delle alte energie e gettato le basi per un ulteriore futuro sviluppo del materiale.
Questo lavoro è stato svolto presso i laboratori del Dipartimento di Scienze dei Materiali dell’Università di Milano-Bicocca, in collaborazione con il Centro Europeo per la Ricerca Nucleare (CERN, Ginevra, Svizzera) e con il Lawrence Berkeley National Laboratory (Berkeley, USA). Parte dei dati è stata ottenuta in collaborazione con Saint Gobain Research (Aubervilliers, Parigi, Francia) e con l’Istituto di Fisica dell’Accademia delle Scienze della Repubblica Ceca (Praga, Repubblica Ceca).Scintillating materials find a wide variety of applications in ionizing radiation detection systems, monitoring and imaging, real time dosimetry in the medical field, homeland and industrial security, and high energy physics. In the recent years, the development of new, fast, and performing scintillators has been an active field of research. Scintillating fiber technology freshly raised a lot of interest because its extreme flexibility can provide a powerful tool for innovative detector designs. This thesis focuses on the study of scintillating fibers made of silica glass which show efficient luminescent properties when activated with rare-earth ions, like Cerium and Praseodymium. Both fundamental and practical aspects are discussed, in view of the improvement and optimization of the material performances for application perspectives in the future generation of high energy physics detectors. With this objective, the effects of high dose levels of ionizing radiation on the transparency of the material are studied. The fine-tuning of the activator content incorporated in the silica matrix and of the sol-gel synthesis and fiber drawing processes allow to obtain a good light guiding and a well-controlled optical quality. The feasibility of a simultaneous readout of Cherenkov and scintillation light is demonstrated in high energy calorimetry conditions, probing Ce-doped silica fibers embedded in a small detector prototype exposed to beams of electrons. Silica fibers can be considered as promising candidates in the framework of the dual readout calorimetry approach, which aims at compensating the energy fluctuations, inherent to the detection of hadronic particles. A deep understanding of the factors limiting the scintillation performances is of primary importance for future material engineering: they are found to be mainly related to the presence of point defects, which compete with the luminescent centers in capturing the free carriers created upon irradiation and introduce a delay in the recombination kinetics. A fundamental study of the role of defects in silica fibers, detrimental for the scintillation efficiency, is proposed and discussed. The potential of silica fibers for applications in high energy physics detectors is outlined and further optimization of the material technology is foreseen. This work was performed at the Department of Materials Science at the University of Milano - Bicocca, in collaboration with the European Organization for Nuclear Research (CERN, Switzerland) and with the Lawrence Berkeley National Laboratory (US). Some measurements were carried out in collaboration with Saint Gobain Research (France) and the Institute of Physics of the Czech Academy of Sciences (Czech Republic).
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Dow, K. L., M. V. Sykes, F. J. Low, and F. Vilas. "Detection of Earth Orbiting Objects by IRAS." Steward Observatory, The University of Arizona (Tucson, Arizona), 1989. http://hdl.handle.net/10150/623903.
Full textAbstract:
A systematic examination of 1836 images of the sky constructed from scans made by the Infrared Astronomical Satellite has resulted in the detection of 466 objects which are shown to be in Earth orbit. Analysis of the spatial and size distribution and thermal properties of these objects, which may include payloads, rocket bodies and debris particles, is being conducted as one step in a feasibility study for space -based debris
detection technologies.
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VILLAVICENCIO, ANNA L. C. H. "Avaliacao dos efeitos da radiacao ionizante de sup60Co em propriedades fisicas , quimicas e nutricionais dos feijoes PHASEOLUS VULGARIS L. e VIGNA UNGUICULATA (L.) WALP." reponame:Repositório Institucional do IPEN, 1998. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10785.
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Tese (Doutoramento)
IPEN/T
Faculdade de Ciencias Farmaceuticas, Universidade de Sao Paulo - CF/USP
31
Ratcliff, Paul Ronald. "Background rejection in gas detectors." Thesis, University of Leicester, 1988. http://hdl.handle.net/2381/35768.
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Investigations have been made on the minimisation of the background count rate detected in proportional counters, while maximising the signal detection efficiency. Two methods of background rejection have been developed, based on the time profile of the shaped detector pulses and on the lateral extent of the induced charge distribution on the cathode. Both these systems have proved highly efficient, and the former has been applied to a multiwire proportional chamber designed as a monitor for plutonium lung contamination, an application where high efficiency detection is critical. This instrument, which incorporates full six-sided "massless" guard cells, and utilises real-time data acquisition and handling by microcomputer, has been developed, optimised, and assessed as a possible competitor to the phoswich detectors in use at present and the solid state detectors under development. Results indicate that the counter is likely to offer no more than a marginal improvement in sensitivity, insufficient to justify its increased compexity and higher costs.
32
Davies, Glyn. "Emission tomography in the determination of the spatial distribution of neutron induced radionuclides." Thesis, University of Surrey, 1989. http://epubs.surrey.ac.uk/847355/.
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Work has been carried out to investigate the applicability of Neutron Induced Emission Tomography (NIET) to areas of non-destructive testing within the nuclear industry. The principal application was the scanning of irradiated nuclear fuel rods. In addition to its medical uses, tomography has been employed in many areas of non-destructive testing. However, the applications have generally used transmission tomography to examine structure. NIET provides a method of determining the spatial distribution of radionuclides produced by the action of neutrons by activation or fission processes. This has applications as an extension of neutron activation analysis and as a method of non-destructive testing for use in the nuclear industry. The work has involved the use of a number of experimental tomography scanners. Various test objects have been scanned using both emission and transmission tomography and computer programs were developed to collect, process and reconstruct the data. High resolution detectors were used to scan single and multi-energetic radionuclides in test objects designed to model various characteristics of nuclear fuel rods. The effects of scattering on image quality were examined and a method of scattering correction based upon the use of an additional energy window was applied. The work showed the viability of using NIET to study the distribution of radionuclides within objects such as irradiated fuel pellets. It also demonstrated the need for reducing the scattering component within images. The use of narrow energy windows and a high resolution detector were shown to be succesful in reducing the effects of scattering. The employment of scattering correction using additional energy windows was shown to be necessary when scanning multi-energetic radionuclides.
33
Kerr, G. A. "Experimental developments towards a long-baseline laser interferometric gravitational radiation detector." Thesis, University of Glasgow, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378181.
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Ariyawansa, Gamini. "Semiconductor Quantum Structures for Ultraviolet-to-Infrared Multi-Band Radiation Detection." Digital Archive @ GSU, 2007. http://digitalarchive.gsu.edu/phy_astr_diss/17.
Full textAbstract:
In this work, multi-band (multi-color) detector structures considering different semiconductor device concepts and architectures are presented. Results on detectors operating in ultraviolet-to-infrared regions (UV-to-IR) are discussed. Multi-band detectors are based on quantum dot (QD) structures; which include quantum-dots-in-a-well (DWELL), tunneling quantum dot infrared photodetectors (T-QDIPs), and bi-layer quantum dot infrared photodetectors (Bi-QDIPs); and homo-/heterojunction interfacial workfunction internal photoemission (HIWIP/HEIWIP) structures. QD-based detectors show multi-color characteristics in mid- and far-infrared (MIR/FIR) regions, where as HIWIP/HEIWIP detectors show responses in UV or near-infrared (NIR) regions, and MIR-to-FIR regions. In DWELL structures, InAs QDs are placed in an InGaAs/GaAs quantum well (QW) to introduce photon induced electronic transitions from energy states in the QD to that in QW, leading to multi-color response peaks. One of the DWELL detectors shows response peaks at ∼ 6.25, ∼ 10.5 and ∼ 23.3 µm. In T-QDIP structures, photoexcited carriers are selectively collected from InGaAs QDs through resonant tunneling, while the dark current is blocked using AlGaAs/InGaAsAlGaAs/ blocking barriers placed in the structure. A two-color T-QDIP with photoresponse peaks at 6 and 17 µm operating at room temperature and a 6 THz detector operating at 150 K are presented. Bi-QDIPs consist of two layers of InAs QDs with different QD sizes. The detector exhibits three distinct peaks at 5.6, 8.0, and 23.0 µm. A typical HIWIP/HEIWIP detector structure consists of a single (or series of) doped emitter(s) and undoped barrier(s), which are placed between two highly doped contact layers. The dual-band response arises from interband transitions of carriers in the undoped barrier and intraband transitions in the doped emitter. Two HIWIP detectors, p-GaAs/GaAs and p-Si/Si, showing interband responses with wavelength thresholds at 0.82 and 1.05 µm, and intraband responses with zero response thresholds at 70 and 32 µm, respectively, are presented. HEIWIP detectors based on n-GaN/AlGaN show an interband response in the UV region and intraband response in the 2-14 µm region. A GaN/AlGaN detector structure consisting of three electrical contacts for separate UV and IR active regions is proposed for simultaneous measurements of the two components of the photocurrent generated by UV and IR radiation.
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MARIN, HUACHACA NELIDA S. "Teste do cometa e teste de germinacao na deteccao do tratamento de alimentos com radiacao ionizante." reponame:Repositório Institucional do IPEN, 2002. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11029.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Singo, Thifhelimbilu Daphney. "Development of a high flux neutron radiation detection system for in-core temperature monitoring." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/19999.
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Thesis (PhD)--Stellenbosch University, 2012.ENGLISH ABSTRACT: The objective of this research was to develop a neutron detection system that incorporates a mass spectrometer to measure high neutron flux in a nuclear reactor environment. This system consists of slow and fast neutron detector elements for measuring fluxes in those energy regions respectively. The detector should further be capable of withstanding the harsh conditions associated with a high temperature reactor. This novel detector which was initially intended for use in the PBMR reactor has possible applications as an in-core neutron and indirect temperature-monitoring device in any of the HTGR. Simulations of a generic HTGR core model were performed in order to obtain the neutron energy spectrum with emphasis on the behavior of three energy regions, slow, intermediate and fast neutrons within the core at different temperatures. The slow neutron flux which has the characteristic of a Maxwell- Boltzmann distribution were found to shift to larger values of neutron flux at higher energies as the fuel temperature increased, while fast neutron flux spectra remained relatively constant. In addition, the results of the fit of the slow neutron flux with a modified Maxwell-Boltzmann equation confirmed that in the presence of the neutron source, leakage and absorption, the effective neutron temperatures is above the medium temperatures. From these results, it was clear that the detection system will need to monitor both slow and fast neutron flux. Placing neutron detectors inside the reactor core, that are sensitive to a particular energy range of slow and fast neutrons, would thus provide information about the change of temperature in the fuel and hence act as an in-core temperature monitor. A detection mechanism was developed that employs the neutron-induced break-up reaction of 6Li and 12C into α-particles. These materials make excellent neutron converters without interference due to γ-rays, as the contributions from 6Li(γ,np)4He and 12C(γ,3α) reactions are negligible. The mass spectrometer measures the 4He partial pressure as a function of time under high vacuum with the help of pressure gradient provided by a high-vacuum turbomolecular pump and a positive-displacement fore-vacuum pump connected in series. A cryogenic trap, which contains a molecular sieve made of pellets 1.6 mm in diameter, was also designed and manufactured to remove impurities which cause a background in the lighter mass region of the spectrum. The development and testing of the high flux neutron detection system were performed at the iThemba Laboratory for Accelerator Based Sciences (LABS), South Africa. These tests were carried out with a high energy proton beam at the D-line neutron facility, and with a fast neutron beam at the neutron radiation therapy facility. To test the principle and capability of the detection system in measuring high fluxes, a high intensity 66 MeV proton beam was used to produce a large yield of α-particles. This was done because the proton inelastic scattering cross-section with 12C nuclei is similar to that of neutrons, with a threshold energy of about 8 MeV for both reactions. Secondly, the secondary fast neutrons produced from the 9Be(p,n)9B reaction were also measured with the fast neutron detector. The response of this detection system during irradiation was found to be relatively fast, with a rise time of a few seconds. This is seen as a sharp increase in the partial pressure of 4He gas as the proton or neutron beam bombards the 12C material. It was found that the production of 4He with the proton beam was directly proportional to the beam intensity. The number of 4He atoms produced per second was deduced from the partial pressure observed during the irradiation period. With a neutron beam of 1010 s−1 irradiating the detector, the deduced number of 4He atoms was 109 s−1. When irradiation stops, the partial pressure drops exponentially. This response is attributed to a small quantity of 4He trapped in the present design. Overall, the measurements of 4He partial pressure produced during the tests with proton and fast neutron beams were successful and demonstrated proof of principle of the new detection technique. It was also found that this system has no upper neutron flux detection limit; it can be even higher than 1014 n·cm−2·s−1. The lifetime of this detection system in nuclear reactor environment is practically unlimited, as determined by the known ability of stainless steel to keeps its integrity under the high radiation levels. Hence, it is concluded that this high flux neutron detection system is excellent for neutron detection in the presence of high γ-radiation level and provides real-time flux measurements.
AFRIKAANSE OPSOMMING: Die doel van hierdie navorsing was om ’n neutrondetektorstelsel te ontwikkel wat hoë neutronvloed binne in ’n kernreaktor kan meet. Die stelsel bevat twee aparte detektorelemente sodat die termiese sowel as snelneutronvloed gemeet kan word. Die detektor moet verder in staat wees om die strawwe toestande, kenmerkend aan ’n hoë temperatuur reaktor, te kan weerstaan. Die innoverende detektorstelsel, oorspronklik geoormerk vir gebruik in die PBMR reaktor, het toepassingsmoontlikhede as in-kern neutron- sowel as indirekte temperatuurmonitor. Simulasies van ’n generiese model van ’n HTGR reaktorkern is uitgevoer ten einde die neutronenergiespektrum in die kern by verskillende temperature te bekom met klem op die gedrag van neutrone in drie energiegroepe: stadig (termies), intermediêr en snel (vinnig). Daar is bevind dat die stadige neutrone, wat ’n Maxwell-Boltzman verdeling toon, in intensiteit toeneem en dat die piek na hoër energie verskuif met toename in temperatuur, terwyl die vinnige neutronspektrum relatief onveranderd bly. ’n Passing van die stadige spektrum op ’n gemodifiseerde Maxwell-Boltzmann verdeling het bevestig dat die effektiewe neutrontemperatuur weens die teenwoordigheid van bronterme, verliese en absorpsie, hoër as die temperatuur van die medium is. Hierdie resultate maak dit duidelik dat die detektorstelsel beide die stadige sowel as die vinnige neutronvloed moet kan waarneem. Deur detektorelemente wat sensitief is vir die onderskeie spekrale gebiede in die reaktorhart te plaas, kan informasie bekom word wat tot in-kern temperatuur herleibaar is sodat die stelsel inderdaad as indirekte temperatuurmonitor kan dien. Die feit dat alfa-deeltjies geproduseer word in neutron-geïnduseerde opbreekreaksies van 6Li en 12C is as die basis van die nuwe opsporingsmeganisme aangewend. Hierdie materiale funksioneer uitstekend as neutron-selektiewe omsetters in die teenwoordigheid van gamma-strale aangesien laasgenoemde se bydraes tot helium produksie via die 6Li(γ,np)4He en 12C(γ,3α) reaksies, weglaatbaar is. Die massaspektrometer meet die tydgedrag van die 4He parsiële druk binne ’n hoogvakuum wat met behulp van ’n seriegeskakelde kombinasie van ’n turbomolekulêre en positiewe-verplasingsvoorpomp verkry word. ’n Koueval met ’n molekulêre sif, bestaande uit 1.6 mm diameter korrels, is ontwerp en vervaardig om onsuiwerhede te verwyder wat andersins as agtergrond by die ligter gedeelte van die massaspektrum sou wys. Die ontwikkeling en toetsing van die hoëvloed detektorstelsel is te iThembaLABS (iThemba Laboratories for Accelerator Based Sciences) gedoen. Dit is uitgevoer deur gebruik te maak van die hoë energie protonbundel van die D-lyn neutronfasiliteit asook van die bundel vinnige neutrone by die neutronterapiefasiliteit. Om die beginsel en vermoë te toets om by ’n hoë neutronvloed te kan meet, is van die intense 66 MeV protonbudel gebruik gemaak om ’n hoë opbrengs alfa-deeltjies te verkry. Dit is gedoen omdat die reaksiedeursnit vir onelastiese verstrooiing van protone vanaf 12C kerne soortgelyk is aan die van neutrone, met ’n drumpelenergie van 8 MeV vir beide reaksies. Tweedens is die sekondêre vinnige neutrone afkomstig van die 9Be(p,n)9B reaksie ook met die neutrondetektor gemeet. Daar is bevind dat die reaksietyd van die deteksiestelsel tydens bestraling relatief vinnig is, soos gekenmerk deur ’n stygtyd van etlike sekondes. Laasgenoemde manifesteer as ’n toename in die parsiële druk van die 4He sodra die proton- of neutronbundel op die 12C teiken inval. Daar is verder bevind dat die 4He produksie direk eweredig aan die bundelintensiteit is. Vir ’n neutronbundel van nagenoeg 1010 s−1, invallend op die neutrondetektor, is vanaf die gemete parsiële druk afgelei dat die produksie van 4He atome sowat 109 s−1 beloop. In die geheel beoordeel, was die meting van die 4He parsiële druk tydens die toetse met vinnige protone en neutrone suksesvol en het dit die nuwe meetbeginsel bevestig. Dit is verder bevind dat die meetstelsel nie ’n beperking op die boonste neutronvloed plaas nie, maar dat dit vloede van selfs hoër as 1014 s−1 kan hanteer. Die leeftyd van die detektorstelsel in die reaktor is prakties onbeperk en onderhewig aan die bevestigde integriteit van vlekvrystaal onder hoë bestraling. Die gevolgtrekking is dus dat die nuwe detektorstelsel uitstekend geskik is vir die in-tyd meting van ’n baie hoë vloed van neutrone ook in die teenwoordigheid van intense gammabestraling.
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Damon, Raphael Wesley. "Determination of the photopeak detection efficiency of a HPGe detector, for volume sources, via Monte Carlo simulations." Thesis, University of the Western Cape, 2005. http://etd.uwc.ac.za/index.php?module=etd&.
Full textAbstract:
The Environmental Radioactivity Laboratory (ERL) at iThemba LABS undertakes experimental work using a high purity germanium (HPGe) detector for laboratory measurements. In this study the Monte Carlo transport code, MCNPX, which is a general-purpose Monte Carlo N &minusParticle code that extends the capabilities of the MCNP code, developed at the Los Alamos National Laboratory in New Mexico, was used. The study considers how various parameters such as (1) coincidence summing, (2) volume, (3) atomic number (Z) and (4) density, affects the absolute photopeak efficiency of the ERL&rsquo
s HPGe detector in a close geometry (Marinelli beaker) for soil, sand, KCl and liquid samples. The results from these simulations are presented here, together with an intercomparison exercise of two MC codes (MCNPX and a C++ program developed for this study) that determine the energy deposition of a point source in germanium spheres of radii 1 cm and 5 cm.
A sensitivity analysis on the effect of the detector dimensions (dead layer and core of detector crystal) on the photopeak detection efficiency in a liquid sample and the effect of moisture content on the photopeak detection efficiency in sand and soil samples, was also carried out. This study has shown evidence that the dead layer of the ERL HPGe detector may be larger than stated by the manufacturer, possibly due to warming up of the detector crystal. This would result in a decrease in the photopeak efficiency of up to 8 % if the dead layer of the crystal were doubled from its original size of 0.05 cm. This study shows the need for coincidence summing correction factors for the gamma lines (911.1 keV and 968.1 keV) in the 232Th series for determining accurate activity concentrations in environmental samples. For the liquid source the gamma lines, 121.8 keV, 244.7 keV, 444.1 keV and 1085.5 keV of the 152Eu series, together with the 1173.2 keV and 1332.5 keV gamma lines of the 60Co, are particularly prone to coincidence summing. In the investigation into the effects of density and volume on the photopeak efficiency for the KCl samples, it has been found that the simulated results are in good agreement with experimental data. For the range of sample densities that are dealt with by the ERL it has been found that the drop in photopeak efficiency is less than 5 %. This study shows that the uncertainty of the KCl sample activity measurement due to the effect of different filling volumes in a Marinelli beaker is estimated in the range of 0.6 % per mm and is not expected to vary appreciably with photon energy. In the case of the effect of filling height on the efficiency for the soil sample, it was found that there is a large discrepancy in the trends of the simulated and experimental curves. This discrepancy could be a result of the use of only one sand sample in this study and therefore the homogeneity of the sample has to be investigated. The effect of atomic number has been found to be negligible for the soil and sand compositions for energies above 400 keV, however if the composition of the heavy elements is not properly considered when simulating soil and sand samples, the effect of atomic number on the absolute photopeak efficiency in the low energy (<
400 keV) region can make a 14 % difference.
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El-Abbassi, Hanan. "Characterisation of semi-insulating GaAs and InP for use in radiation detection." Thesis, University of Surrey, 2004. http://epubs.surrey.ac.uk/843598/.
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A range of optical, electrical and radiation techniques were used to study the performance of GaAs and semi-insulating InP detectors, to assess their suitability as low energy X-ray detectors for medical imaging applications, all of which were grown using different techniques and approaches. Alpha-particle spectroscopy experiments were used to study the charge collection efficiency of the materials. Also used were optical and electrical methods such as photoluminescence mapping, photo-induced current transient spectroscopy and capacitance-voltage measurements. Room-temperature photoluminescence mappings have also been used to reveal the excellent homogeneity of the SI InP samples and epitaxial GaAs. Understanding of the best growth technique(s) and suitable device fabrication methods for these materials would encourage their commercial use as a radiation detector. For instance, an inverse correlation of the Fe concentration in InP with the mobility lifetime product of the carriers has been shown to exist. A low amount of Fe is required for good detection properties, although a sufficient amount is needed to render the material semi-insulating. Fe-diffused InP by annealing of Fe concentration 4.5 x 1015 cm-3 is shown to have an electron T-product of 3.6 X 10-5 cm2/ V and hole r-product of 1.5 X 10-5 cm2/ V at room temperature. This is still about an order of magnitude lower than that typically observed for CdTe, which is currently the best candidate with regards to medical imaging applications. The suitability of epitaxial GaAs for use as a radiation detector was also studied. This material, with a thickness of 200 - 500 mus was produced at the Marie Curie University, Paris, using a novel growth technique. A sample of only 1.3 x 1014 cm-3 impurity concentration exhibited carrier lifetimes of up to 2 mus at room temperature. The depletion width at this temperature is only 20 mum at 10 V. Gamma measurements with 60 keV photons of the epitaxial material shows photopeaks with a charge collection efficiency of 80% at 90 V and energy resolution 4.9 %.
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West, Matthew K. "Diffusion of sulfur into natural diamond : characterization and applications in radiation detection /." free to MU campus, to others for purchase, 1999. http://wwwlib.umi.com/cr/mo/fullcit?p9964011.
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Fratelli, Ilaria <1992>. "Novel Semiconducting Materials and Thin Film Technologies for High Energy Radiation Detection." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amsdottorato.unibo.it/9560/1/tesi_ilariaFratelli.pdf.
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Nowadays the development of real-time ionizing radiation detection system operating over large areas is crucial. Increasing quest for flexible, portable, low cost and low power consumption sensors pushed the scientific community to look for alternative materials and technologies able to fulfill these new requirements. In this thesis the potentiality of organic semiconductors and metal oxides as material platforms for novel ionizing radiation sensors is demonstrated. In particular, organic semiconductors are human tissue-equivalent and this represents a unique and desirable property for the development of dosimeters to be employed in the medical field. The ionizing radiation sensors described in this thesis have been designed, fabricated and characterized during my PhD research and are realized onto polymeric foils leading to flexible devices operating at low voltages, in ambient condition and able to directly detect X-rays, gamma-rays and protons. Following the study of the properties and of the mechanisms of interaction between the radiation and the active layers of the sensors, several strategies have been adopted to enhance the efficiency of these detectors. X-rays dosimeters based on organic semiconductors have been realized presenting record sensitivity values compared with the state of the art for large area radiation detection. The unprecedentedly reported performance led to the possibility to testing these devices in actual medical environments. Moreover, the proof-of-principle demonstration of a dosimetric detection of proton beams by organic-based sensors is reported. Finally, a new sensing platform based on metal oxides is introduced. Combining the advantages of amorphous high mobility oxide semiconductors with a multilayer dielectric, novel devices have been designed, capable of providing a sensitivity one order of magnitude higher than the one shown by the standard RADFETs. Thanks to their unique properties, these sensors have been integrated with a wireless readout system based on a commercial RFID tag and its assessment is presented.
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Persson, Anders. "Vavilov-Cerenkov Radiation Near Dielectric Boundaries with Application to Ultrahigh Energy Neutrino Detection." Thesis, Uppsala universitet, Institutet för rymdfysik, Uppsalaavdelningen, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-160062.
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In this diploma thesis, we present a thorough investigation of the Vavilov-Cerenkov (VC) effect and its application to the detection of ultrahigh energyneutrinos. Neutrinos have no net charge and cannot emit VC radiation(VCR) but when they interact with a stationary medium such radiation isproduced by the Askar'yan effect. It has been proposed to use the lunarregolith as a detector material for such neutrino interactions, but in orderto do so, the VCR emitted from neutrino interactions has to be filtered outfrom that of other energetic particles impinging upon and penetrating intothe lunar surface. Since the principal difference between these emissions isdependent on the depth at which they occur, any boundary effects dependenton the distance from the point of emission to the surface is of interest.Therefore we examine the behavior of VCR near dielectric boundaries withextra care, both analytically and numerically. In order to keep the physicalpicture as clear as possible the analytical derivations are conducted in thetemporal domain. The boundary problem is studied both with respect tothe Maxwell boundary conditions and the method of images. In order toverify the analytic results and to make further investigations, a numericalMaxwell solver for the general VCR problem was constructed. The analyticand numeric results are then compared and proven to be equivalent. TheMaxwell solver is used to study the boundary problem and it is shown thatthe VCR emitted in a medium near the surface does not depend on the distanceto the surface in the same way as the opposite problem with a chargeabove the medium. In the case of a charge distribution traveling partiallyon both sides of the boundary some frequency dependent effects are shown.
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Barley, Steven Keith. "Investigation of the muon component of EAS initiated by primary radiation from Hercules X-1." Thesis, University of Nottingham, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238221.
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Quinlan, Brendan Robert. "A Model For The Absorption Of Thermal Radiation By Gold-Black." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/63888.
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The work presented here addresses an important topic in thermal radiation detection when gold-black is used as an absorber. Sought is a model to simulate the absorption of thermal radiation by gold-black.
Fractal geometry is created to simulate the topology of gold-black. Then electrical circuits based on the topology are identified that capture the physics of the interaction between the gold-black material and incident electro-magnetic radiation. Parameters of the model are then adjusted so results obtained are comparable to absorption data from the literature.
Potential next-generation radiometric instruments will likely involve thermal radiation detectors using gold-black as an absorbing medium. A model that accurately simulates gold-black absorption will be an important tool in their design.Master of Science
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Philip, Long Nguyen. "Development of a Multi Radiation Type Survey Meter Using Aromatic Ring Polymers Undoped with Fluorescent Molecules." Kyoto University, 2016. http://hdl.handle.net/2433/217749.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第20066号
農博第2195号
新制||農||1045(附属図書館)
学位論文||H28||N5022(農学部図書室)
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 髙橋 千太郎, 教授 近藤 直, 教授 飯田 訓久
学位規則第4条第1項該当
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Spisni, Giacomo. "Radiation-sensitive OXide semiconductor Field Effect Transistor (ROXFET): a novel thin-film device for real-time and remote ionizing radiation detection." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/24394/.
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Nowadays, ionizing radiation detectors find application in a wide range of contexts, spanning from industry to healthcare and security. In this background, the next generation of ionizing radiation sensors require devices that are accurate, light-weight, relatively inexpensive and capable to be read-out in real-time and remotely. In recent years, research groups at the University of Bologna and the NOVA University of Lisbon (Portugal) have developed Radiation-sensitive OXide-semiconductor Field-Effect Transistors (ROXFET) to be employed as fast, real-time x-ray dosimetry detection systems. The ROXFET operation relies on the principle that, upon exposure to radiation, excitons are generated in the dielectric and separated into hole and electron charge carriers. While electrons are able to diffuse out of the dielectric layer, hole charges get trapped and contribute to the field-effect in the semiconductor channel. Macroscopically, such contribution is observable as a shift in transistor threshold voltage toward negative values, which turns out to be proportional to the absorbed radiation dose. In laboratory tests, ROXFET devices proved to be sensitive in a wide energy range and capable of providing reliable information about their radiation exposure history. Furthermore, the design of ROXFET can be integrated on a flexible substrate and read in real-time as a passive radiofrequency tag. Aim of this thesis work was to contribute to the development of the ROXFET technology. To this end, I carried out multiple characterization tests on recently fabricated samples, revealing how they outperformed previously observed radiation sensitivities. Later on, I worked in a clean-room facility to fabricate new ROXFET experimental samples by leveraging the knowledge acquired from previous observations.
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Merzi, Stefano. "Novel applications of FBK SiPMs in the detection of low energy ionizing radiation." Doctoral thesis, Università degli studi di Trento, 2020. http://hdl.handle.net/11572/276309.
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Silicon photon multipliers, or SiPMs, are single photon detectors that have grown increasing interest in the last decade as an alternative to photomultiplier tubes in many field of physics, engineering and medicine.
Compared to PMTs, SiPMs are more compact, rugged and operate at much lower bias voltage, in the order of tens of volts. Moreover they are insensitive to magnetic field and can achieve a very high radiopurity
SiPM detectors work on the principle of a diode operated above the breakdown voltage, in Geiger mode. In this condition, the electric field in the depletion region is high enough that the electron-hole pairs, generated by a single photon absorption through photoelectric effect, create secondary charges by impact ionization in a potentially diverging avalanche effect that can be exploited to generate a macroscopical current at the output of the diode.
Thanks to this effect, the SiPM is capable of counting the number of impinging photons down to single photon level. Noise sources in the SiPM include dark counts and correlated noise. Dark counts are counts happening when an electron-hole pair is generated in the active volume of the device in absence of photon absorptions. These events are caused either by thermal generation, diffusion from the neutral region or by tunnel effect. Correlated noise events, or counts, on the other hand, are generated when a primary firing cell retriggers after a certain time or cause the triggering of another cell. All these noise sources introduce errors in the photon count by adding fake events to the output signal of the detector.Traditional SiPM application is 511 keV gamma-ray detection in PET machines, using scintillator LYSO crystals to convert a single gamma ray into a flash of visible photons. An application based on the same principle was studied in this thesis by coupling FBK RGB-HD SiPMs with CsI:Tl crystals in order to detect lower energy X and gamma-rays. This setup has proven to be effective in the detection of radiation with energy as low as 5.9 keV with a resolution of 38.3%, which is the minimum value of energy resolution measured with SiPMs coupled to scintillator crystals at such low energy. At the same time it was observed that large area detectors provided a dynamic range wide enough to simultaneously detect radiation ranging from 6.4 keV to 122 keV with minimal saturation. In another activity of this thesis it was developed a simulation software that reproduces the behaviour of a SiPM under different light conditions by taking into account the detector efficiency, the dead time and the recharge behaviour of its cells and theoretical modelizations of the noise parameters that affect the measurement. From a given light profile the simulation generates a waveform that reproduces the one measured during the operation of real SiPMs. This waveform was then analysed using FBK software developed for SiPM characterization and the results showed an excellent agreement between the simulated detector and a reference SiPM. This software will become a useful tool for the design of SiPMs for future experiments because it will allow to tune the properties of the detectors to specific applications and it will reduce the need of layout and process split to find the optimal configuration of the detector parameters.Among all FBK technologies, this work was focused on the position-sensitive LG-SiPM. Unlike standard SiPMs, which have a single output, the LG-SiPM employs a more complex structure that splits the current signal into four output channels with ratios depending on the position of the impinging light on its surface. Center of mass calculations are used to reconstruct the position of the firing cell with precision down to some tens of microns while maintaining the fast time response of SiPMs. An application of the LG-SiPM was studied in the framework of the ARIADNE experiment in collaboration with the university of Liverpool. In this work the LG-SiPM was used to detect scintillation light coming from ionization tracks generated by alpha particles inside a CF4 TPC chamber. The ionized electrons where drifted through the action of a high electric field in the TPC towards a THGEM where they created light with timing depending on the distance of each track segment from the scintillator. The LG detector was able to reconstruct the 3D track particle inside the chamber with an error below 8 mm RMS inside the 40 l chamber and, at the same time, to reconstruct the energy released by the particle as function of time and calculate the total energy of the interacting particle and its linear energy transfer. These results open a novel approach for the TPC position reconstruction that combines the low number of readout channels needed for the LG detector to its time-continuous response which allows to reconstruct the tree-dimensional track of a particle inside the chamber.During the experiment it emerged the presence of an artifact that drifted all the reconstructed tracks towards the centre of the detection area, at the end of the signal. This effect was studied by creating a second simulation software that recreates the electrical behaviour of the LG-SiPM equivalent circuit when one or more cells trigger. It was simulated the output of the circuit with different light conditions and different values of the circuit elements and it was observed that the presence of the artifact was related to low intensity currents flowing through the net of the LG-SiPM metal tracks and quenching resistors. Several simulations were run in order to identify the optimal configuration of parameters for the reduction of this unwanted effect and to implement improvements in future LG-SiPM productions.Another application of the LG-SiPM in the field of radiation detection is the position reconstruction of the scintillation light emitted by gamma-rays in a monolithic crystal. Using a thin CsI:Tl crystal and lowering the detector temperature it was possible to distinguish different positions of interaction on the surface of the detector with an error below 1 mm FWHM. This technology can be effective for the creation of monolithic, position sensitive X and gamma-ray detector with good energy resolution for low energy spectroscopy or medical imaging devices.
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SOUZA, CLEBER N. de. "Desenvolvimento de um sistema dosimetrico para feixes de eletrons de enegias altas." reponame:Repositório Institucional do IPEN, 1994. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10379.
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Made available in DSpace on 2014-10-09T12:38:00Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T14:04:34Z (GMT). No. of bitstreams: 1 05589.pdf: 5500511 bytes, checksum: e678ea0585ad825ea9f71a7ce347adb4 (MD5)
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Dinar, Nesrine. "Development of neutron detectors for use in radiation protection." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS160.
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La première partie de cette étude a consisté à tester les performances de plusieurs détecteurs de neutrons habituellement utilisés pour la radioprotection des accélérateurs de particules à haute énergie. La comparaison a été réalisée à la CERF, un champ unique qui simule le spectre neutronique rencontré à proximité d’accélérateurs à haute énergie et à des altitudes de vols commerciaux. La campagne a permis de comprendre le comportement des différents détecteurs et de quantifier leurs sur/sous- estimations par rapport à la fonction d'équivalent de dose ambiante de référence et de réaliser le benchmark des nouvelles simulations FLUKA réalisée en 2017. La deuxième partie de cette thèse portait sur l’exploration d’un détecteur à neutrons rapides destiné à un nouvel appareil de mesure capable de fonctionner en présence d’un champ magnétique puissant. Le CLYC a été choisi comme candidat potentiel pour la détection neutronique en raison de ses propriétés prometteuses, telles que sa capacité à discriminer les rayons gamma des neutrons rapides et sa résolution énergétique. Cette thèse évalue les performances d'un large cylindre CLYC couplé à une matrice SiPM et compare les résultats à ceux des PMT. Les capacités spectrométriques du CLYC ont été soulignées. Pour le comptage neutronique de nouveaux matériaux ont été étudié en perspectiveThe first part of this study consisted in testing performance of the several neutron detectors usually employed for radiation protec- tion at high-energy particle accelerators. The in- tercomparison was made at CERF, a unique workplace field that simulates the neutron spec- trum encountered in the proximity of high-en- ergy accelerators and at commercial flight alti- tudes. The CERF intercomparison campaign allowed to understand the behaviour of the different detector and quantify their over/underesti- mations with respect to the reference ambient dose equivalent function. Moreover, these experimental data were used to benchmark the new FLUKA simulation performed in 2017. The second part of this thesis was the investigation of a fast neutron detector for a novel radiation survey meter (called B-RAD) able to operate in the presence of a strong magnetic field, to be used for radiation surveys e.g. in the LHC experimental areas. The CLYC was selected as potential candidate for neutron detec-tion because of its promising properties, such as its capability to discriminate gamma rays from fast neutrons and its energy resolution. This thesis evaluated the performance of a 1- inch right CLYC cylinder coupled with a large SiPM array and compared the result with PMTs. The capacity of the CLYC+SiPm for spectros-copy was underligned. For neutron counting, new materials were investigated
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Upadhya, Prasanth Chandrashekara. "Coherent generation and detection of Terahertz radiation : time domain Terahertz spectroscopy of molecular crystals." Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614771.
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Abubakar, Y. M. "Silicon and silicon carbide radiation detectors for alpha and neutron detection at elevated temperatures." Thesis, University of Surrey, 2016. http://epubs.surrey.ac.uk/813046/.
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Harsh radiation environments are characterised by high temperature, high radiation fluence high pressure and sometimes vibration. These conditions are present in nuclear reactor cores and oil and gas prospecting. Because of the limited supply of 3He, new materials are needed for neutron porosity measurements in order to reduce the cost of nuclear well logging and reduce dependence on 3He. High radiation fluence affects material's performance for radiation detection applications. For decades silicon has been an important material for radiation monitoring because of its cost effectiveness and relative availability. In recent years, the level of radiation produced in high energy physics (HEP) experiments has drastically increased, which compels searching for special materials that can withstand high radiation fluence. On the other hand, silicon carbide (SiC) devices have also been receiving considerable attention because of their properties that make them excellent candidates for harsh radiation media applications. The main aim of this work was to investigate the thermal neutron detection ability of SiC diodes covered with standard LiF neutron converter layers at elevated temperatures up to 500 K for extended periods of time - up to 100 hours. For this purpose, a range of 4H- silicon carbide(SiC) devices, based on semi-insulating bulk material and epitaxial diodes has been characterised in terms of current voltage, capacitance voltage and alpha spectroscopy performance as a function of temperature to underpin the neutron tests with an understanding of changes in Schottky Barrier Height, conductivity and effective doping with temperature before proceeding to neutron tests. In parallel, a series of Silicon (Si) Schottky diodes was also studied with various levels of proton induced radiation damage as part of an international collaboration. LiF coated non-damaged devices have served as a benchmark for the SiC tests at room temperature. It was found that all epitaxial SiC devices tested exhibited an increased effective dopant density due to increased activation of dopants with increasing temperature, leading to some reduction in depletion width, and hence active thickness as well as to an increase in leakage current. Nevertheless, leakage currents only compromised the energy resolution of alpha particle spectroscopy (within the limitations of the set-up) at the highest applied bias voltages. Long term stability tests indicate that the devices respond in a stable manner within 8 hours of operation or less and, maintain performance for at least 24 hours. Stability is reached faster at higher temperatures. So far, the silicon devices show attractive response to alpha radiation and confirm their possible applications for hard radiation detection at room temperature including the large hadron colliders (LHC). The alpha particle detection and its stability at high temperature demonstrated by SiC samples is an indication of their suitability in harsh radiation detection applications. In addition, their neutron detection and its stability imply future application in oil and gas prospecting and nuclear reactor monitoring.