To see the other types of publications on this topic, follow the link: Measurement of radiation.
Dissertations / Theses on the topic 'Measurement of radiation'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Measurement of radiation.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Xiang, Xuwu. "The delta-Sobolev approach for modeling solar spectral irradiance and radiance." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/25801.
Full text
2
Tootell, A. K. "Radiation dose assessment : measurement, estimation and interpretation." Thesis, University of Salford, 2018. http://usir.salford.ac.uk/48041/.
Full textAbstract:
New technologies or methods of image acquisition are driven by the need for increased anatomical information to improve diagnostic accuracy or surgical planning. These new technologies are often accompanied with additional radiation dose yet this can be justified through the consideration of the benefit it brings. Examples include the use of CT colonography instead of double contrast barium enemas, CT urography replacing intravenous urography and, in nuclear medicine imaging the increased use of CT imaging as part of single photon emission tomography and positron emission tomography to correct emission data or localise or characterise identified lesions. Manufacturers are quick to promote their systems as “low-dose” but little independent evaluation of this claim existed. In the context of nuclear medicine, the additional imaging raised questions as to the use of the attenuation correction data specifically. The question of should the cross sectional images be reviewed for pathology was has been the focus of debate. It was recognised that the quality of these images is poor due to the “low-dose” acquisition. The research presented in this thesis and portfolio of published work aimed to establish an accurate method of assessing the radiation dose, initially from the CT attenuation correction acquisition, but later in other imaging modalities. In this thesis eight papers are used to illustrate the methods developed in this work, and how they were applied to other fields of medical imaging. Six of these papers were completed as the first author and the remainder as co-author. Initially, the concepts of radiation dose were critically evaluated. Following identification of sub-optimal techniques, steps were taken to improve the accuracy of dose measurement using thermoluminescent dosimeters, digital dosimeters and simulation through software. These techniques have been analysed critically and where appropriate improvements are recommended. Radiation dose, in particular the associated risk, is a challenging concept to convey to patients and care givers and simply providing a figure of dose does not convey the required information needed to allow consent to be given. Methods by which radiation dose and risk can be interpreted is critiqued with reference to published literature. The thesis concludes with a description of the intellectual contribution illustrating the role played as first author and as a co-author in the works included in the portfolio and a review of impact considering citation metrics and downloads. It was also decided to include citations from within the Diagnostic Imaging Research Programme and PhD theses from The University of Salford to demonstrate how research activities within the portfolio of published works have influenced other methodologies and outputs.
3
Kyei, Kofi Adesi. "Pain assessment : the role of the radiation therapist." Thesis, Cape Peninsula University of Technology, 2010. http://hdl.handle.net/20.500.11838/1563.
Full textAbstract:
Thesis (MTech (Radiography))--Cape Peninsula University of Technology, 2010.The focus of this study is the role of the Radiation Therapist (RTT) in the assessment of pain in cancer patients. The study was carried out at a Radiotherapy Department of a large Teaching Hospital in Ghana and addressed the following research questions; 1) What is the role of the RTT in the assessment of pain in cancer patients, 2) Why should the RTTs’ role be extended to include pain assessment, 3) What are the challenges for the RTT when taking on the role of pain assessment in radiation oncology and 4) How can pain assessment become a routine role for the RTT in a busy radiation oncology department? 5) How would this extended role of the RTT assist management of patient? This study was conducted because many cancer patients suffer pain and to many, it can be more debilitating than the primary disease itself. The RTTs who are involved in the daily management of cancer patients during their radiation treatment can find it stressful to witness their patients going through such pain particularly when they do not have a role in the management of pain. In Ghana, there are few radiation oncologists (ROs) and therefore an extended scope for RTTs, that includes pain assessment and a meaningful contribution to the management of their patients’ pain, would be advantageous to all. A mixed method research approach was adopted for gathering quantitative and qualitative data. This included data collection of; interview, observation and review of existing document. A pain questionnaire SF-MPQ-2 by Melzack (2009) was adapted as a tool for assessing pain in the study participants.
4
Jalandoni, D. Jay Moreno. "In-phantom measurement of HE or neutron protection dosimetry." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/16777.
Full text
5
Enshayan, Kamyar Short Ted H. "Measurement of solar radiation transmission in solar ponds /." Connect to resource, 1989. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1145375001.
Full text
6
Enshayan, Kamyar. "Measurement of solar radiation transmission in solar ponds." The Ohio State University, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=osu1145375001.
Full text
7
Tanny, Sean M. "Investigation of Radiation Protection Methodologies for Radiation Therapy Shielding Using Monte Carlo Simulation and Measurement." University of Toledo / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1449853114.
Full text
8
Jordan, Jorge J. "UNDERSTANDING THE NON-CONTACT TEMPERATURE MEASUREMENT TECHNOLOGY." International Foundation for Telemetering, 2005. http://hdl.handle.net/10150/605042.
Full textAbstract:
ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, NevadaThe ability to accurately measure the temperature of different materials has always been a challenge for the Instrumentation Engineer. The use the classic contact type temperature detector such as thermocouples or RTD’s (Resistance Temperature Detectors) has not always shown to be the best approach to obtain the expected measurement. When not used carefully in closed environments, thermocouples and RTD’s could report the environmental temperature rather than the temperature from the product under examination. They are also temperature limited and when needed for applications above those limits, very expensive and low reliable materials are necessary to do the job. The use of non-contact thermometers has become the preferred choice for such applications. They have also come as a solution for the difficulties involved in the temperature measurements of moving targets. The industry has used portable and spot type infrared thermometers for some time, but the demand for better and more precise measurements has brought an incredible number of new products to the market. By means of advanced electronics and new software developments these products are used to cope with the difficulties of acquiring challenging measurements. Some of the same demands have made necessary the use of non-contact temperature measurement devices on aircraft instrumentation applications. The use of these capabilities has allowed the data acquisition community to get valuable data that was very difficult if not impossible to obtain before. In spite of all these facts, this promising emerging technology demands very careful attention before it is put to good use. The many products and solutions available do not accurately address every problem and the selection of the wrong technology for a specific task can prove to be fatal. The use of non-contact temperature devices is not an easy “off the shelf” pick but rather an option that demands knowledge of the infrared measurement theory as well as a complete understanding of the material under observation. The intention of this paper is to provide a practical understanding on the non-contact temperature measurement methods to the Aircraft Instrumentation Engineer who has not benefited from the use of this exiting technology.
9
Wang, Fei. "Vertical beam emittance correction with independent component analysis measurement method." [Bloomington, Ind.] : Indiana University, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3319892.
Full textAbstract:
Thesis (Ph.D.)--Indiana University, Dept. of Physics, 2008.Title from PDF t.p. (viewed on May 13, 2009). Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 4823. Adviser: Shyh-Yuan Lee.
10
Bogue, Jonathan Nelson. "Evaluation of Patient-Scatter Factors for Radiation Therapy ShieldingUsing Physical Measurement in a "Good" Geometry." University of Toledo Health Science Campus / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=mco1525447575821026.
Full text
11
Scott-Fleming, Ian Crerar 1955. "DIGITAL SIGNAL PROCESSING METHODS FOR ESTIMATING SOLAR RADIOMETER ZERO AIRMASS INTERCEPT PARAMETERS." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276442.
Full text
12
Rowland, James D. "Modelling solar irradiance on a slope under a leafless deciduous forest." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59293.
Full textAbstract:
This thesis investigates variations in solar irradiance incident upon sloping surfaces under deciduous forest in winter. A model is presented for prediction of solar irradiance at the surface which accounts for slope inclination and orientation, surrounding topography, isotropic absorption of solar radiation by the crown space, and shadows cast by the stem space.Field data from two sites of different slope and aspect attest to the validity of the model; errors, based on 20-minute averages of instantaneous values, are 15.5% (RMSE) and $-$1.9% (MBE). Error is partially due to reliance upon global radiation measurements above canopy at a different site (partially cloudy conditions) and sampling error (sunny sky conditions). The variability of solar irradiance at the surface, and in the error of predicted values, is found to vary with sky condition, solar zenith and incidence angles, and slope orientation. However, integration to hourly and/or daily time periods improves model performance significantly.
13
Irving, Benjamin. "Radiation dose measurement and prediction for linear slit scanning radiography." Master's thesis, University of Cape Town, 2008. http://hdl.handle.net/11427/3251.
Full textAbstract:
Includes abstract.Includes bibliographical references (leaves 112-117).
This study describes dose measurements made for linear slit scanning radiography (LSSR) and a dose prediction model that was developed for LSSR. The measurement and calculation methods used for determining entrance dose and effective dose (E) in conventional X-ray imaging systems were verified for use with LSSR. Entrance dose and E were obtained for LSSR and compared to dose measurements on conventional radiography units. Entrance dose measurements were made using an ionisation chamber and dosemeter; E was calculated from these entrance dose measurements using a Monte Carlo simulator. Comparisons with data from around the world showed that for most examinations the doses obtained for LSSR were considerably lower than those of conventional radiography units for the same image quality. Reasons for the low dose obtained with LSSR include scatter reduction and the beam geometry of LSSR. These results have been published as two papers in international peer reviewed journals. A new method to calculate entrance dose and effective dose for LSSR is described in the second part of this report. This method generates the energy spectrum for a particular set of technique factors, simulates a filter through which the beam is attenuated and then calculates entrance dose directly from this energy spectrum. The energy spectrum is then combined with previously generated organ energy absorption data for a standard sized patient to calculate effective dose to a standard sized patient.Energy imparted for different patient thicknesses can then be used to adjust the effective dose to a patient of any size. This method is performed for a large number of slit beams moving across the body in order to more effectively simulate LSSR. This also allows examinations with technique factors that vary for different parts of the anatomy to be simulated. This method was tested against measured data and Monte Carlo simulations. This model was shown to be accurate, while being specifically suited to LSSR and being considerably faster than Monte Carlo simulations.
14
Sheikh, Zahoor Ahmad. "Measurement of the coherence length of atomic two-photon radiation." Thesis, University of Stirling, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359253.
Full text
15
Priestly, Kory James. "An end-to-end model of the Earth Radiation Budget Experiment (ERBE) Earth-viewing nonscanning radiometric channels." Thesis, Virginia Tech, 1993. http://hdl.handle.net/10919/34619.
Full textAbstract:
The Earth Radiation Budget Experiment (ERBE) active-cavity radiometers are used to measure the incoming solar, reflected solar, and emitted longwave radiation from the Earth and its atmosphere. The radiometers are carried by the National Aeronautics and Space Administration's Earth Radiation Budget Satellite (ERBS) and the National Oceanic and Atmospheric Administration's NOAA-9 and NOAA-10 spacecraft. Four Earth-viewing nonscanning active-cavity radiometers are carried by each platform. Two of the radiometers are sensitive to radiation in the spectral range from 0.2 to 50 μm, while the other two radiometers are sensitive to radiation in the spectral range from 0.2 to 5.0 μm. Each set of radiometers comes in a wide-field-of-view (WFOV) and a medium-field-of-view (MFOV) configuration. The cavities of the shortwave (visible) radiometers are covered with a Suprasil® hemispherical dome to filter out the incoming longwave radiation.
Knowledge of the optical and physical properties of the radiometers allows their responses to be predicted using a low-order physical model. A high-level, dynamic electrothermal end-to-end model which accurately predicts the radiometers dynamic output has also been completed. This latter model is used to numerically simulate the calibration procedures of the actual instruments. With calibration of the end-to-end model complete, a simulation of a phenomena referred to as the "solar blip" is conducted to investigate the instruments' responses to steep transient events. The solar blip event occurs when direct solar radiation is briefly incident to the active-cavity radiometric channels as the spacecraft passes into and out of the Earth's shadow.Master of Science
16
Wooten, Hasani Omar. "Calculation of internal dose conversion factors for selected spallation products." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/17247.
Full text
17
Blaney, S. "Gamma radiation methods for clamp-on multiphase flow metering." Thesis, Cranfield University, 2008. http://dspace.lib.cranfield.ac.uk/handle/1826/5655.
Full textAbstract:
The development of a cost-effective multiphase flow meter to determine the individual
phase flow rates of oil, water and gas was investigated through the exploitation of a
single clamp-on gamma densitometer and signal processing techniques. A fast-sampling
(250 Hz) gamma densitometer was installed at the top of the 10.5 m high, 108.2 mm
internal diameter, stainless steel catenary riser in the Cranfield University multiphase
flow test facility. Gamma radiation attenuation data was collected for two photon
energy ranges of the caesium-137 radioisotope based densitometer for a range of air,
water and oil flow mixtures, spanning the facility’s delivery range.
Signal analysis of the gamma densitometer data revealed the presence of quasi-periodic
waveforms in the time-varying multiphase flow densities and discriminatory
correlations between statistical features of the gamma count data and key multiphase
flow parameters.
The development of a mechanistic approach to infer the multiphase flow rates from the
gamma attenuation information was investigated. A model for the determination of the
individual phase flow rates was proposed based on the gamma attenuation levels; while
quasi-periodic waveforms identified in the multiphase fluid density were observed to
exhibit a strong correlation with the gas and liquid superficial phase velocity parameters
at fixed water cuts.
Analysis of the use of pattern recognition techniques to correlate the gamma
densitometer data with the individual phase superficial velocities and the water cut was
undertaken. Two neural network models were developed for comparison: a single
multilayer-perceptron and a multilayer hierarchical flow regime dependent model. The
pattern recognition systems were trained to map the temporal fluctuations in the
multiphase mixture density with the individual phase flow rates using statistical features
extracted from the gamma count signals as their inputs. Initial results yielded individual
phase flow rate predictions to within ±10% based on flow regime specific correlations.
18
Leach, Mark. "A new method for holographic measurement of microwave antenna radiation patterns." Thesis, Northumbria University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.416351.
Full textAbstract:
The rate at which new communications technologies are being developed has been immense and will continue to intensify for the foreseeable future. This evolution is fuelled by the desire to meet the wants and needs of the global community, by developing devices able to offer ever-increasing functionality, with greater complexity. To achieve this designers are forced to move to higher and higher frequencies. The antenna, as one of the fundamental building blocks of any radiated wave system, and as such, must develop along with the evolution of the communication system be it for, mobile, satellite or point to point systems. Antenna designers need to be able to test antenna, to ensure they exhibit the characteristics to which they were designed. Antenna test becomes progressively more difficult and costly as both, the operating frequency and the size of the antenna increase, especially for the measurement of the antenna Far-Field radiation pattern. Either the distance over which the measurement must be made becomes unfeasibly large or expensive measurement equipment is required to attain the phase component of the antenna field, where traditional methods for measuring close to the antenna are applied. Techniques have been developed to eliminate the need for the expensive phase measurement at reduced distances. Specifically of interest in this thesis, is the optical process of Off-Axis holography. The process allows phase information to be retained in a scalar measurement by use of a phase coherent known reference source. The reference desired reference source is a plane wave, which although possible at optical frequencies with the use of lasers is problematic at microwave frequencies. To date the plane wave characteristic required has been approximated using conventional radiating elements, which degrades the quality of the recorded holographic image. This thesis proposes a novel implementation of the Off-Axis hologram system, for application in the microwave frequency region. The novel system developed here addresses the problem of generating the desired plane wave characteristic. The conventional radiating element used to provide the near plane wave reference is replaced by a synthetic equivalent, which allows the magnitude and phase of the reference beam to be directly controlled at every measurement location required. Practical verification of the novel system proposed has been performed, with comparisons made between the results obtained from the novel technique and standard techniques used in industry. The comparisons show that the novel implementation is valid and able to provide good repeatable results.
19
Lester, Martin Richard. "Selective intensimetry for the measurement of sound radiation from building elements." Thesis, Liverpool John Moores University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294022.
Full text
20
Papaiōannou, D. "An automated antenna radiation pattern measurement system controlled by a microcomputer." Thesis, University of Kent, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355690.
Full text
21
Drangsholt, Mark Thomas. "Measurement of lifetime dental radiographic radiation exposure to the cranial meninges /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/10904.
Full text
22
Hofverberg, Petter. "A New Measurement of Low Energy Antiprotons In the Cosmic Radiation." Doctoral thesis, Stockholm : Fysik, Kungliga Tekniska högskolan, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9427.
Full text
23
Bainbridge, Neville. "Thermal design of microcalorimeters for the measurement of radiation absorbed dose." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/46953.
Full text
24
De, Almeida Jose Sergio. "Measurement of radiation in complex geometries and comparison with calculational techniques." Thesis, Loughborough University, 2000. https://dspace.lboro.ac.uk/2134/36072.
Full textAbstract:
During the development of flight tests of a spacecraft, heat exchange occurs among the many physically separated subsystem surfaces through the phenomenon of thermal radiation. Considering the increasing complexity of the geometrical forms and shapes in the design of such systems, the monitoring and control of the radiative heat fluxes taking place in the multi-reflecting, absorbing and emitting heat transfer environment are very critical. Because the analytical solution of thermal radiation in such geometrically complex three-dimensional systems is not practical, extensive numerical modelling techniques are widely used to predict radiative heat fluxes on the many thermally active surfaces. From experience, it is found that this can be very difficult and not at all commensurate with fast feedback unless the analysis is from a simple system layout. Considering that a relatively new approach dedicated to the basic analysis of radiative heat flux has been developed by the heat transfer community as a numerical approximation called the Discrete Ordinates Method (DOM), a first question did arise in terms of how well an enhanced and more comprehensive formulation based on this concept would fulfil the task of achieving faster results whilst still accurately predicting radiative heat transfer in three-dimensional, more complex geometries.
25
Swanberg, Erik Lars Jr. "Improving the performance of a personnel monitor based on long range alpha detection." Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/17103.
Full text
26
Buchhauser, David 1950. "Design, construction, and testing of a microprocessor controlled tracking and scanning solar spectroradiometer." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276567.
Full textAbstract:
A versatile solar spectroradiometer has been designed which is capable of measuring direct solar radiation, the solar aureole, and sky radiance far from the sun. An active tracker consisting of a quadrant detector, telescope and stepper-motor driven alt-azimuth mount is used to position the spectroradiometer by computer control for solar tracking and almucantur scans. An internally baffled telescope designed to suppress stray light is employed as the optical receiver, and a photodiode serves to convert the collected flux to an electrical signal. A digitally controlled gain-switching transimpedance amplifier is used to scale the photodiode output to accommodate the large signal range encountered between measuring direct solar radiation and sky radiance well away from the sun. Example measurements are presented which demonstrate the system's capabilities.
27
Phillips, Amy Louise. "ABSOLUTE CALIBRATION OF, AND ATMOSPHERIC MEASUREMENTS USING, A MULTIBAND FIELD RADIOMETER (RADIOMETRY)." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275418.
Full text
28
Chan, Kin Wa (Karl), University of Western Sydney, of Science Technology and Environment College, and School of Computing and Information Technology. "Lateral electron disequilibrium in radiation therapy." THESIS_CSTE_CIT_Chan_K.xml, 2002. http://handle.uws.edu.au:8081/1959.7/538.
Full textAbstract:
The radiation dose in radiation therapy is mainly measured by ion chamber. The ion chamber measurement will not be accurate if there is not enough phantom material surrounding the ion chamber to provide the electron equilibrium condition. The lack of electron equilibrium will cause a reduction of dose. This may introduce problems in treatment planning. Because some planning algorithms cannot predict the reduction, they over estimate the dose in the region. Electron disequilibrium will happen when the radiation field size is too small or the density of irradiated material is too low to provide sufficient electrons going into the dose volume. The amount of tissue required to provide electron equilibrium in a 6MV photon beam by three methods: direct calculation from Klein-Nisina equation, measurement in low density material phantom and a Monte Carlo simulation is done to compare with the measurement, an indirect method from a planning algorithm which does not provide an accurate result under lateral electron disequilibrium. When the error starts to happen in such planning algorithm, we know that the electron equilibrium conditions does not exist. Only the 6MV photon beam is investigated. This is because in most cases, a 6MV small fields are used for head and neck (larynx cavity) and 6MV fields are commonly used for lung to minimise uncertainity due to lateral electron at higher energies.Master of Science (Hons)
29
Swart, Gillian. "Measurement of absorbed dose for paediatric patients for the purpose of developing dose guidelines in paediatric radiology." Thesis, Peninsula Technikon, 2004. http://hdl.handle.net/20.500.11838/1546.
Full textAbstract:
Thesis (MTech (Radiography))--Peninsula Technikon, 2004The radiation risks associated with children are higher than the risk for adults. Children have growing organs and they have a longer life expectancy than that of adults. As a consequence the effects of damage from radiation could be greater than in adults. Children who receive radiation damage may pass genetic damage onto future generations. This study was carried out to investigate the optimal effective x-ray dose young children need to receive who have radiographic examination to the chest at Tygerberg Hospital, South Africa. Chest radiographs are documented as being the most common radiographic examination done on children. The age groups of children participating in this study were 0-1 year, 1-5 years and 5-10 years. A total of 67 children were involved and the absorbed doses for 134 views of the anterior-posteria (AP) chest and lateral chest were measured. Entrance surface dose (ESD) values were determined, and measured mean ESD (mGy) and the ESD range was reported for each age group. This was done by attaching thermolurninescent dosirneters (TLD pellets) to the patients skin at the entrance point of the x-ray beam. The results were compared to similar studies done in Ireland and Nigeria From the ESD values obtained the absorbed doses ofthe eyes, heart, liver, thyroid and genitals could be calculated by using the "Childdose" programme ofthe NRPB. The ESD dose levels for South Africa compare favourably with Ireland. However the Nigerian values differed greatly from those of Ireland and South Africa It was very encouraging to note the comparative results achieved at Tygerberg Hospital especially due to the fact that this was the first time such study had been conducted in the Tygerberg Hospital Radiology Department. The results also compare favourable with that achieved by a group working in the United Kingdom. This group does similar surveys every five years as part of their radiation protection programme. The results were also in line with the UNSCEAR document of2000. v This study could serve as a valuable source of reference to radiographers and radiologists when performing paediatric radiology especially as the radiation absorbed dose could be used as a baseline to create awareness of size of dose received, and to limit deleterious radiation doses to patients and to prevent unnecessary exposures. A second significant outcome of the study was the effect that added filters had on the x-ray beam generated. Experiments were done in which the filtration filters were added sequentially. It was found that if the filtration was increased to 2mmAl the dose to the patient decreased by more than 20%. At 50 and 60 kV the density of the x-ray image on film only increased by 2%. From these results it may be concluded that an increase in filtration thickness used for paediatric chest x-rays should be giVIng reduced dose readings and assisting with radiation protection ofthe patient.
30
Bell, Kenneth Frazer. "Measurement of the deposition of aerosol particles to skin, hair and clothing." Thesis, Imperial College London, 1999. http://hdl.handle.net/10044/1/8608.
Full text
31
Langford, Thomas J. "Measurement of the Surface and Underground Neutron Spectra with the UMD/NIST Fast Neutron Spectrometers." Thesis, University of Maryland, College Park, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3611818.
Full textAbstract:
The typical fast neutron detector falls into one of two categories, Bonner sphere spectrometers and liquid scintillator proton recoil detectors. These two detector types have traditionally been used to measure fast neutrons at the surface and in low background environments. The cosmogenic neutron spectrum and flux is an important parameter for a number of experimental efforts, including procurement of low background materials and the prediction of electronic device faults. Fast neutrons can also cause problems for underground low-background experiments, through material activation or signals that mimic rare events. Current detector technology is not sufficient to properly characterize these backgrounds.
To this end, the University of Maryland and the National Institute of Standards and Technology designed, developed, and deployed two Fast Neutron Spectrometers (FaNS) comprised of plastic scintillator and 3He proportional counters. The detectors are based upon capture-gated spectroscopy, a technique that demands a delayed coincidence between a neutron scatter and the resulting neutron capture after thermalization. This technique provides both particle identification and knowledge that the detected neutron fully thermalized. This improves background rejection capabilities and energy resolution.
Presented are the design, development, and deployment of FaNS-1 and FaNS-2. Both detectors were characterized using standard fields at NIST, including calibrated 252Cf neutron sources and two monoenergetic neutron generators. Measurements of the surface fast neutron spectrum and flux have been made with both detectors, which are compared with previous measurements by traditional detectors. Additionally, FaNS-1 was deployed at the Kimballton Underground Research Facility (KURF) in Ripplemead, VA. A measurement of the fast neutron spectrum and flux at KURF is presented as well. FaNS-2 is currently installed in a shallow underground laboratory where it is measuring the muon-induced neutron flux and spectrum.
32
Rizzo, Carlo Anthony Edward. "Phase retrieval near-field/far-field measurement techniques for quasi-optical large apertures." Thesis, University of Sheffield, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310888.
Full text
33
Evans, Thomas M. "The measurement and calculation of nanodosimetric energy distributions for electrons and photons." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/19264.
Full text
34
Gillespie, Jodie Corbridge. "Measurement of The Temperature Dependence of Radiation Induced Conductivity in Polymeric Dielectrics." DigitalCommons@USU, 2013. https://digitalcommons.usu.edu/etd/1953.
Full textAbstract:
This study measures Radiation Induced Conductivity (RIC) in five insulating polymeric materials over temperatures ranging from ~110 K to ~350 K: polyimide (PI or Kapton HNTM and Kapton ETM), polytetraflouroethylene (PTFE or TeflonTM), ethylene-tetraflouroethylene (ETFE or TefzelTM), and Low Density Polyethylene (LDPE). RIC occurs when incident ionizing radiation deposits energy and excites electrons into the conduction band of insulators. Conductivity was measured when a voltage was applied across vacuum-baked, thin film polymer samples in a parallel plate geometry. RIC was calculated as the difference in sample conductivity under no incident radiation and under an incident ~4 MeV electron beam at low incident dose rates of 0.01 rad/sec to 10 rad/sec. The steady-state RIC was found to agree well with the standard power law relation, σRIC(D) = kRIC(T) DÄ(T) between conductivity, óRIC and adsorbed dose rate, D. Both the proportionality constant, kRIC, and the power, Ä, were found to be temperature-dependent above ~250 K, with behavior consistent with photoconductivity models developed for localized trap states in disordered semiconductors. Below ~250 K, kRIC and Ä exhibited little change in any of the materials.
35
Wachsmuth, Matthew George. "Measurement and Characterization of Terahertz Radiation Propagating Through a Parallel Plate Waveguide." PDXScholar, 2011. https://pdxscholar.library.pdx.edu/open_access_etds/317.
Full textAbstract:
As the amount of study into the terahertz (THz) region of the electromagnetic spectrum steadily increases, the parallel plate waveguide has emerged as a simple and effective fixture to perform many experiments. The ability to concentrate THz radiation into a small area or volume enables us to analyze smaller samples and perform more repeatable measurements, which is essential for future research. While the fundamental physics of PPW transmission are understood mathematically, the practical knowledge of building such a fixture for the THz domain and taking measurements on it with a real system needs to be built up through experience. In this thesis, multiple PPW configurations are built and tested. These include waveguides of different lengths and opening heights, using lenses and antennas to focus and collect radiation from the input and output, and different amounts of polish on the waveguide surface. A basic resonator structure is also built and measured as a proof of concept for future research. The two most useful propagation modes through the waveguide, the lowest order transverse magnetic (TEM) and transverse electric (TE) modes, were characterized on all of the setups. Additionally, a flexible fixture was designed and measured which will allow future work in the THz field to be much more reliable and repeatable.
36
Bloom, Dylan C. "Design and Verification of a LabVIEW Automated Antenna Radiation Pattern Measurement System." DigitalCommons@CalPoly, 2018. https://digitalcommons.calpoly.edu/theses/1916.
Full textAbstract:
In 2014, Toyon Research Corporation donated a 6’x6’x8’ anechoic chamber to the Cal Poly EE department to advance student education in the areas of antennas and wireless communications. An anechoic chamber is a room designed to suppress electromagnetic radiation reflections so that accurate measurement of radio frequency (RF) systems such as wireless radios and antennas can take place. Despite the fact that Cal Poly already has a larger anechoic chamber, primarily used for antenna characterization, it is the purpose of this project to design, code, and equip the new chamber so that it performs at least as good, or better than, the existing chamber.
Radiation pattern is a key characteristic that describes the directionality or gain of an antenna, and it is important for quantifying and qualifying how an antenna will perform as part of a wireless communication system. Radiation pattern measurement can be time consuming because it requires measuring an antenna’s transmission or reception in in all directions. In both the old and new antenna measurement systems (AMS), a vector network analyzer (VNA) measures signals transmitted between the antenna under test (AUT) and an RF field probe within the antireflective environment of the anechoic chamber. The new system synchronizes VNA measurement with the rotation of the AUT using the automation software LabVIEW and a Sunol Sciences FS-121 antenna positioner. Then, Matlab plots the data collected by LabVIEW as well as calculates useful antenna metrics including half power beam width (HPBW) and directivity. LabVIEW also makes the AMS easy to operate because of its graphical user interface.
The new anechoic chamber completes measurements faster than Cal Poly’s existing chamber, with good accuracy and ease of use. The new chamber works best with smaller antennas at frequencies up to 6 GHz and beyond. Radiation patterns have good SNR, and match with simulations and measurements done in the larger chamber. However, due to its smaller size the new AMS is not a replacement for the existing larger system when testing antennas larger than 1 m or at frequencies below 2 GHz.
37
Thébaut, Jonathan. "Measurement driven, electron beam modeling and commissioning for a Monte Carlo treatment planning system with improved accuracy." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=67026.
Full textAbstract:
With the development of modern linear accelerators, the dosimetry of complex electron beams technique became a challenge for physicists. Over the past few years, lots of efforts have been done on developing accurate and fast dose algorithms for electrons. Numerous Monte Carlo (MC) models of therapeutic electron beams are presented in the literature. However, beam models built solely with manufacturer specifications of the medical accelerator do not systematically provide acceptable agreements with measurements. Clinically accurate beam models are crucial to MC treatment planning as electron dose calculations found in commercial treatment planning system (TPS) are generally inaccurate for complex geometry or with heterogeneities. Therefore, there is a strong motivation to use highly accurate MC simulations as standard information for commissioning commercial TPS. The current research project consists in developing an improved accurate electron beam model based on detailed information of the linear accelerator and to incorporate it into an in-house TPS: The McGill Monte Carlo Treatment Planning (MMCTP).Avec le développement d'accélérateurs linéaires, la dosimétrie de techniques complexes de faisceaux d'électrons devient un défi pour les physiciens. Ces dernières années, des efforts considérables ont été faits pour développer un algorithme de calcul de dose précis et rapide pour les faisceaux d'électrons. De nombreux modèles Monte Carlo (MC) pour des faisceaux thérapeutiques d'électrons sont connus dans la littérature. Néanmoins, des modèles de faisceaux construits seulement avec les spécifications des constructeurs d'accélérateurs linéaires ne fournissent pas systématiquement des résultats en concordance avec les mesures. Au niveau clinique, des modèles de faisceaux précis sont d'une importance capitales pour les calculs de dose par Monte Carlo, dans la mesure où les algorithmes de calcul de faisceaux d'électrons présents dans les systèmes de plannification de traitements (SPT) commerciaux sont générallement imprécis dans des cas comportant des geométries complexes ou des hétérogénéités. Par conséquent, il y a une grande motivation à utiliser des simulations de Monte Carlo précis, comme information standard pour la mise en service des SPT commerciaux. La recherche présentée dans ce manuscrit vise à développer un modèle amélioré et précis de faisceaux d'électrons basé sur des informations détaillées d'accélérateurs linéaires et à incorporer ce modèle dans un SPT: le « McGill Monte Carlo Treatment Planning (MMCTP) ».
38
Pater, Piotr. "A method for in-treatment measurement of residual respiratory motion of organs for stereotactic body radiation therapy." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32606.
Full textAbstract:
Stereotactic Body Radiation Therapy is a radical treatment method for small lesions in the body where a surgical dose of radiation is given to attempt to sterilize the lesion. One of its limitations lays in the respiratory motion of the target during treatment. For this technique, high precision and accuracy on the dose delivered to the target is critical. This work produced a measurement method for the target's position and motion, during treatment, without giving extra dose to the patient. This method is based on a statistical analysis of the position of implanted metallic markers, visible on treatment portal images. The method was implanted in a software written entirely in Real Basic (Real Software, Texas, USA) code. The software was tested with images of a respiratory phantom of known motion. The motion statistics detected by the software corresponded to the measured values. Results show that the software can be applied on clinical patient data. Some studies of patient data are presented to demonstrate the software's possibilities.La radiothérapie stéréotactique extracérébrale est une méthode de traitement radicale, où une forte dose de radiation est donnée à une petite lésion dans le corps, pour tenter de la stériliser. Une des limites de cette thérapie réside dans la difficulté d'irradier la cible précisément et exactement à la dose prescrite, puisqu'elle est constamment induite en mouvement par la respiration du patient durant le traitement. Ce travail a permis de concevoir une méthode de mesure de la position et du mouvement de la cible, durant le traitement, sans donner de dose additionnelle au patient. Cette méthode est basée sur une analyse statistique de la position de marqueurs métalliques implantés chirurgicalement près de la cible et visibles sur des images portales prises durant le traitement. Un logiciel codé en Real Basic (Real Software, Texas, USA) intégrant la méthode a été écrit. Le logiciel a été testé avec un fantôme respiratoire de déplacement connu. Les statistiques du mouvement obtenues par le logiciel correspondaient aux valeurs mesurées sur le fantôme. Les résultats montrent que le logiciel peut-être utile pour l'analyse du mouvement dans des cas cliniques de patients. Quelques exemples d'études cliniques sur des images de patients sont présentés pour démontrer les possibilités du logiciel et de la méthode utilisée.
39
Aldosary, Ghada. "The measurement of the linear energy transfer of various radiotherapeutic beams in the clinic: a feasibility study." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=119715.
Full textAbstract:
Beam quality specification is essential in accurate characterization of radiotherapeutic beams. Amongst the many beam quality parameters that have been defined and applied, the linear energy transfer (LET) is one of the few parameters that provide an insight into the radiobiological effects of radiation. In this work, we investigated the feasibility of establishing a beam quality detector that allows for the indirect measurement of LET in the clinic. Intrinsic energy dependence was induced in an Exradin A12 ionization chamber by replacing its chamber wall with geometrically identical yet material varying walls. The energy response of these detectors was characterized by investigating the effect of varying chamber wall materials on the polarity and ion recombination correction factors. Using these detectors, measurements were performed across a wide range of beam energies (for both photons and electrons). Monte Carlo simulations were used to validate the measured data, and to obtain the mean primary electron energy of each beam. The data were used to calculate and relate the LET to the unique signals measured with the detectors under each radiation beam, which allowed us to establish a calibration curve. The calibration curve was validated by using the detectors to measure the signals produced by a radiation beam of unknown LET. The results showed that by using the calibration curve, the LET of radiation beams—with energies falling within our range—can be derived by performing a set of simple measurements. The derived LET values were found to be accurate to within a total uncertainty of nearly 10%. As a practical application to this method, the LET variations across 10 x 10 cm^2 radiation fields of 6 MV and 18 MV photons were measured. The results showed that within our uncertainty, the LET of high-energy photon beams outside of the field edges can vary to up to 20% from their central point values. The proposed method provides a new approach for a practical and efficient measurement of the LET in the clinic.La spécification de la qualité de faisceau est essentielle pour la caractérisation de faisceau radio thérapeutique. Parmi les multiples paramètres de qualité de faisceau qui ont été défini et appliqué, le transfert d'énergie linéaire (LET) est un des seuls qui donne une indication sur les effets radiobiologique des radiations. Dans ce travail, nous avons investigué la faisabilité d'établir un detector de qualité de faisceau qui permet de mesurer indirectement le LET en clinique. La réponse d'énergie intrinsèque a été induite dans une chambre d'ionisation Extradin A12 en replaçant sa paroi par différents matériaux en gardant une géométrie identique. La réponse énergétique de ces détecteurs a été caractérisée en investiguant les effets des différents matériaux de la paroi de la chambre sur les facteurs de corrections de polarité et de recombinaison ionique. Les mesures, utilisant ces détecteurs, ont été effectuées pour un large éventail d'énergie de faisceau (de photons et d'électrons). Des simulations de Monte Carlo ont été utilise pour valider les données mesurée ainsi que pour obtenir l'énergie moyenne des électrons primaires pour chaque faisceau. Les données ont été utilisées pour calculer and établir une relation entre le LET et le signal unique mesuré avec les détecteurs pour chaque faisceau de radiation, ce qui nous a permit d'établir une courbe de calibration. Cette courbe de calibration a été validée en utilisant les détecteurs pour mesurer les signaux produit par un faisceau de radiation possédant un LET inconnu. Les résultats démontrent qu'en utilisant la courbe de calibration, le LET de faisceau de radiation – avec des énergies comprises dans notre éventail – peuvent être dérivé en performant une série de simple mesures. Les valeurs de LET ainsi obtenues sont précises avec une incertitude total d'environ 10%. Pour une application pratique de cette méthode, les variations de LET ont été mesurées sur des champs de radiation de 10 x 10 cm^2 pour 6 MV et 18 MV. Les résultats montrent que compris dans notre incertitude, le LET des faisceaux de photon à haute énergie en dehors des limites du champ peut varier jusqu'à 20% de sa valeur au point central. La méthode proposée permet une nouvelle approche pratique et efficace pour la mesure du LET en clinique.
40
Daughtrey, William D. "Development of an underwater LDV for use in the high radiation case." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/17256.
Full text
41
Essid, Samir. "Interactive microcomputer model for solar radiation evaluation and photovoltaic output comparison." Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/90967.
Full textAbstract:
The basic resource of all solar systems is the sun, and a knowledge of the quantity of the energy available is of prime importance. Although the solar radiation outside the atmosphere is known and almost constant, various climatic factors cause wide variations in its value on the earth's surface. In addition, the relative position of the sun with respect to local points of interest will allow surfaces with different orientations and tracking ability to receive different quantities of solar energy. This research focuses on the effect of cloud cover on the solar radiation received on the earth's surface and presents computer models that calculate its value for the best system configuration. Then a complete assessment of the electrical output of such a system is given. With this purpose in mind, two solar resource evaluation models have been developed; the first method is based on a direct statistical approach correlating clear sky total daily radiation with measured daily insolation. This approach has been applied to a few selected sites and offers the procedure for extending the same coefficients to other sites with similar weather patterns. This model has been tested for six sites in Bangladesh . These sites are located around a "reference" site . The predictions made have shown to be quite accurate. The second model uses an analytical approach that combines clear sky methods with "correction" factors which are based on long term recorded solar ra- diation. In addition, this model has been enhanced by an algorithm that selects the optimal surface orientation that maximizes solar output. Finally, the hourly electrical output of the photovoltaic system is calculated after accounting for the various losses. This is presented as part of a complete solar energy evaluation model.M.S.
42
Brucoli, Matteo. "Total ionizing dose monitoring for mixed field environments." Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTS093/document.
Full textAbstract:
La mesure de la dose ionisante est aujourd'hui une tâche cruciale pour une large gamme d'applications fonctionnant dans des environnements de rayonnement sévères. Dans le contexte de l'amélioration de la luminosité du grand collisionneur de hadrons (LHC), la mesure des niveaux de rayonnement le long du complexe d'accélérateurs du CERN va devenir encore plus difficile. A cet effet, une connaissance plus détaillée du champ de rayonnement dans le tunnel de l'accélérateur et ses zones adjacentes devient nécessaire pour définir les exigences d'installation, de déplacement ou de blindage de l'électronique sensible au rayonnement. Dans l’objectif d’améliorer la mesure de la dose absorbée par les systèmes exposés au champ de rayonnement mixte généré par l’accélérateur, des investigations sur des nouveaux dosimètres ont été menées.Dans le cadre de cette recherche, deux dispositifs ont été étudiés et caractérisés pour être utilisés comme dosimètres et éventuellement pour compléter l'utilisation du dosimètre au silicium actuellement utilisé au CERN, à savoir le RADFET (RADiation-sensitive Field Effect Transistor) : un NMOS commercial et un ASIC (Application-specific Integrated Circuit) nommé FGDOS. Les dispositifs ont été sélectionnés selon deux approches opposées : d'une part, la réduction des coûts permettrait d'augmenter la densité des capteurs déployés. En conséquence directe, une carte des doses plus détaillée serait obtenue pour les grands systèmes distribués comme le LHC. D'autre part, la dosimétrie peut être améliorée en déployant des détecteurs plus sensibles, ce qui permettrait de mesurer la dose lorsque les niveaux sont trop faibles pour le RADFET. De plus, des capteurs à plus haute résolution permettraient de caractériser le champ de rayonnement dans un temps plus court, c'est-à-dire avec une luminosité intégrée plus faible.La première approche a été réalisée en recherchant des solutions alternatives basées sur des dispositifs COTS (Commercial Off-The-Shelf), qui réduiraient considérablement les coûts et garantiraient une disponibilité illimitée sur le marché. À cette fin, des recherches ont été menées sur un transistor NMOS discret commercial, qui s'est révélé très sensible au rayonnement.La nécessité d'améliorer la résolution de la mesure de dose a conduit à étudier le FGDOS, un dosimètre en silicium innovant à très haute sensibilité qui permet de détecter des doses extrêmement faibles.La calibration du transistor NMOS et du FGDOS a été effectuées en exposant les dosimètres à des rayons gamma. Leur réponse au rayonnement a été caractérisée en termes de linéarité, de variabilité d'un lot à l'autre et d'effet du débit de dose. L'influence de la température a été étudiée et une méthode pour compenser l'effet de la température a été développée et mise en œuvre.Le FGDOS étant un système sur puce (SoC) avec plusieurs caractéristiques qui font du dosimètre un système extrêmement flexible, la caractérisation de ses différents modes de fonctionnement (actif, passif et autonome) a été effectuée. Suite à la première caractérisation, des questions se sont posées concernant les mécanismes de dégradation de la sensibilité affectant le dosimètre. Pour étudier ce phénomène, des campagnes d’irradiations ont été effectuées avec une puce d'essai incorporant seulement le circuit sensible au rayonnement du FGDOS. L'analyse des expériences a permis de comprendre les processus responsables de la dégradation de la sensibilité, en séparant la contribution du transistor de lecture de celle du condensateur à grille flottante. Les résultats de cette étude nous ont amenés à envisager de nouvelles solutions de conception et des méthodes de compensation.L’aptitude du transistor NMOS et du FGDOS à mesurer la dose ionisante dans les champs de rayonnement mixtes produits par le complexe d’accélérateurs du CERN a été vérifiée à l’aide de test radiatifs accélérés effectués dans le centre de tests en champs mixte à haute énergie du CERN (CHARM)The Total Ionizing Dose (TID) monitoring is nowadays a crucial task for a wide range of applications running in harsh radiation environments. In view of the High-Luminosity upgrade for the Large Hadron Collider, the monitoring of radiation levels along the CERN’s accelerator complex will become even more challenging. To this extent, a more detailed knowledge of the radiation field in the accelerator tunnel and its adjacent areas becomes necessary to design installation, relocation or shielding requirements of electronics sensitive to radiation. Aiming to improve the monitoring of the TID delivered by the mixed radiation field generated within the accelerator system, investigations on new suitable dosimeters have been carried out.With this research, two devices have been studied and characterized to be employed as dosimeter and possibly to complete the use of the silicon sensor currently employed at CERN for TID monitoring, i.e. the RADiation-sensitive Field Effect Transistor (RADFET): a commercial NMOS, and an ASIC (Application-Specific Integrated Circuit) named FGDOS. The devices have been selected following two opposite approaches: on the one hand, reducing the costs would allow the density of the deployed sensors to increase. As a direct consequence, a more detailed dose map would be obtained for large distributed systems like the LHC. On the other hand, the radiation monitoring can be further improved by deploying more sensitive detectors, which would allow to measure the dose where the levels are too low for the RADFET. Moreover, sensors with higher resolution would permit the characterization of the radiation field in a shorter time, which means within a lower integrated luminosity.The first approach has been accomplished by searching for alternative solutions based on COTS (Commercial Off-The-Shelf) devices, which would significantly reduce the costs and guarantee unlimited availability on the market. For this aim, investigations on a commercial discrete NMOS transistor, which was found to be very sensitive to the radiation, has been carried out.The need for improving the resolution of TID monitoring led to investigate the FGDOS, which is an innovative silicon dosimeter with a very high sensitivity that permits to detect extremely low doses.The calibration of the NMOS and the FGDOS have been performed by exposing the dosimeters to γ-ray. Their radiation response has been characterized in terms of linearity, batch-to-batch variability, and dose rate effect. The influence of the temperature has been studied and a method to compensate the temperature effect has been developed and implemented.Being the FGDOS is a System-On-Chip with several features that make the dosimeter an extremely flexible system, the characterization of its operational modes (Active, Passive and Autonomous) have been performed. Following the first characterization, some questions arose concerning the sensitivity degradation mechanisms affecting the dosimeter. To investigate this phenomenon, radiation experiments were performed with a test chip embedding only the radiation sensitive circuit of the FGDOS. The analysis of the experiments allowed the understating of the processes responsible for the sensitivity degradation, by separating the contribution of the reading transistor and the floating gate capacitor. The results of this investigation led us to considerer new design solution and compensation methods.The suitability of the NMOS and the FGDOS for TID measurement in the mixed radiation field produced by the CERN’s accelerator complex has been verified by performing accelerated radiation tests at the Cern High energy AcceleRator Mixed field facility (CHARM). The consistency of both sensors with the RADFET measurement has been demonstrated. The high sensitivity of the FGDOS leads to a significant improvement in terms of TID measurement in mixed radiation fields with respect to the RadFET, especially for low radiation intensities
43
Mengesha, Wondwosen. "NaI(T1) electron energy resolution." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/15963.
Full text
44
Chang, Jon Carlton 1963. "Modification and calibration of a solar spectroradiometer system." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276858.
Full textAbstract:
A solar spectroradiometer is an instrument used for measuring the transmitted solar radiation on a quasi-continuous basis. An existing computer controlled solar spectroradiometer system has been modified and made operable. Test measurements have shown that the signal to noise ratio (which is time of day and wavelength dependent) is at an acceptable level. The chief use of the spectroradiometer will be for atmospheric transmittance studies, which will require calibration of the instrument. Strategies for calibrating the instrument have been discussed.
45
Matos, Carmen. "Robotically Controlled Measurement System for Millimeter-Wave Antennas." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1588180162492972.
Full text
46
Scarboro, Sarah Brashear. "The use of a thyroid uptake system for assaying internal contamination following a radioactive dispersal event." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22639.
Full textAbstract:
Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2008.Committee Chair: Nolan Hertel; Committee Member: Armin Ansari; Committee Member: Chris Wang; Committee Member: Rebecca Howell.
47
Nguyen, Tai K. "Optimization of radiometric channel solar calibration for the Clouds and the Earth's Radiant Energy System (CERES) using the Monte-Carlo method." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06232009-063403/.
Full text
48
Omotere, Olumide Olubunmi. "Improvement of the Soil Moisture Diagnostic Equation for Estimating Root-Zone Soil Moisture." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1157607/.
Full textAbstract:
Soil moisture information can be used accurately in determining the timing and amount of irrigation applied to plants. Pan and Pan et al. proposed a robust and simple daily diagnostic equation for estimating daily soil moisture. The diagnostic equation evaluates the relationship between the soil moisture loss function and the summation weighted average of precipitation. The loss function uses the sinusoidal wave function which employs day of the year (DOY) to evaluate the seasonal variation in soil moisture loss for a given year. This was incorporated into the daily diagnostic equation to estimate the daily soil moisture for a location. Solar radiation is an energy source that drives the energy and water exchanges between vegetation and the atmosphere (i.e., evapotranspiration), and thus impacts the soil moisture dry-down. In this paper, two parameters (the actual solar radiation and the clear sky solar radiation) are introduced into loss function coefficient to improve the estimation of soil moisture. After the Introduction of the solar radiation data into soil moisture loss function, a slight improvement was observed in the estimated daily soil moisture. Pan observed that generally the correlation coefficient between the estimated and the observed soil moisture is above 0.75 and the root mean square error is below 5.0 (%v/v). The introduction solar radiation data (i.e. clear sky solar radiation and actual solar) improve the correlation coefficient average for all the sites evaluated by 0.03 when the root mean square error is generally below 4.5(%v/v) for the entire root zone.
49
Reid, Carlton B. "Measurement of electron beam emittance using optical transition radiation and development of a diffuse screen electron beam monitor." Thesis, Monterey, California : Naval Postgraduate School, 1990. http://handle.dtic.mil/100.2/ADA241893.
Full textAbstract:
Thesis (M.S. in Physics)--Naval Postgraduate School, December 1990.Thesis Advisor: Maruyama, Xavier K. Second Reader: Buskirk, Fred R. "December 1990." Description based on title screen as viewed on April 1, 2010. DTIC Identifier(s): Transition radiation, beam monitors, charged particle beams, diffuse screens, Optical Transition Radiation, Wartski Interferometers, Cerenkov Radiation, theses. Author(s) subject terms: Transition radiation, Lorentz Factor, diffraction pattern, charged particle beam profiling. Includes bibliographical references (p. 110). Also available in print.
50
Streicher, John James. "A new method to compare radiation view factors and a study of bare soil evaporation using microlysimeters." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26645.
Full textAbstract:
In Chapter 1, a numerical computer technique is developed to determine radiation view factors between planar surfaces whose geometry is sufficiently regular so as to be defined by algebraic equations. This technique does not require spherical, cylindrical or rectangular symmetry, although such symmetries may be exploited when they exist. Once the essential geometric problem is formulated, enough generality can be built into the solutions so that certain "new" configurations, derived from translations or rotations of one surface relative to the other, can be solved as a matter of course.
In Chapter 2, a model of bare soil evaporation is tested against measured flux from lysimeters obtained in the Peace River region of British Columbia and Alberta. Hydraulic diffusivity characteristics, measured from separate, adjacent field samples, were used in the model. Certain procedural difficulties in the measurement of hydraulic diffusivity are examined in detail, and recommendations for improvement are made. The degree to which evaporation simulation agrees with measured flux is discussed.Land and Food Systems, Faculty of
Graduate