Journal articles: 'Accelerating voltage'

1

Postek, M. T., and R. C. Tiberio. "Low-Voltage Accelerating-Voltage SEM Magnification Standard Prototype." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 198–99. http://dx.doi.org/10.1017/s0424820100103073.

Full text

Abstract:

The National Bureau of Standards has had a continuing effort for almost a decade to develop feature-size measurement techniques and the associated linewidth standards for the semiconductor industry. Recently, work began on a scanning electron microscope (SEM) based feature-size measurement program specifically aimed at the development and certification of SEM linewidth standards and the associated techniques for their calibration and use.Primary to the development and use of SEM linewidth measurement standards is the calibration of the magnification of the SEM. The only standard reference material presently available from NBS for calibrating the magnification of the SEM is the NBS SRM 484.1 This standard provides a known pitch between gold lines in a nickel matrix that is traceable to NBS primary standards. This standard has proven useful for many SEM applications and should continue to be useful for some time to come. However, since SRM 484 was developed prior to the recent interest in low accelerating voltage operation for integrated circuit wafer inspection and measurement, this SRM, in its present form, is unsuitable for use in many of the newly introduced SEM measurement instruments.

APA, Harvard, Vancouver, ISO, and other styles

2

Miyokawa, T., S. Norioka, and S. Goto. "Development of a conical anode Fe-gun for low voltage SEM." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 978–79. http://dx.doi.org/10.1017/s0424820100106958.

Full text

Abstract:

Field emission SEMs (FE-SEMs) are becoming popular due to their high resolution needs. In the field of semiconductor product, it is demanded to use the low accelerating voltage FE-SEM to avoid the electron irradiation damage and the electron charging up on samples. However the accelerating voltage of usual SEM with FE-gun is limited until 1 kV, which is not enough small for the present demands, because the virtual source goes far from the tip in lower accelerating voltages. This virtual source position depends on the shape of the electrostatic lens. So, we investigated several types of electrostatic lenses to be applicable to the lower accelerating voltage. In the result, it is found a field emission gun with a conical anode is effectively applied for a wide range of low accelerating voltages.A field emission gun usually consists of a field emission tip (cold cathode) and the Butler type electrostatic lens.

APA, Harvard, Vancouver, ISO, and other styles

3

Erdman, Natasha, Charles Nielsen, and Vernon E. Robertson. "Shedding New Light on Cathodoluminescence—A Low Voltage Perspective." Microscopy and Microanalysis 18, no. 6 (December 2012): 1246–52. http://dx.doi.org/10.1017/s1431927612001262.

Full text

Abstract:

AbstractPreviously, imaging and analysis with cathodoluminescence (CL) detectors required using high accelerating voltages. Utilization of lower accelerating voltage for microanalysis has the advantages of reduced beam-specimen interaction volume, and thus better spatial resolution, as well as reduction in electron beam induced damage. This article will highlight recent developments in field emission gun–scanning electron microscope technology that have allowed acquisition of high spatial resolution CL images at very low accelerating voltages. The advantages of low kV CL imaging will be shown using examples of a geological specimen (shale) and a specimen of an industrial grade diamond.

APA, Harvard, Vancouver, ISO, and other styles

4

Dusevich, V. M., J. H. Purk, and J. D. Eick. "Choosing the Right Accelerating Voltage for SEM (An Introduction for Beginners)." Microscopy Today 18, no. 1 (January 2010): 48–52. http://dx.doi.org/10.1017/s1551929510991190.

Full text

Abstract:

Historically, most SEM operators used accelerating voltages that were fairly high, quite often in the range of 15–20 kV. Now progress in electron optics has made low-voltage observations a routine mode of SEM operation. The greatly improved range of utilized accelerating voltages provides the SEM operator with additional flexibility and with additional responsibilities for choosing the right SEM settings for image acquisition.

APA, Harvard, Vancouver, ISO, and other styles

5

Goldenberg, A. L., M. Yu Glyavin, N. A. Zavolsky, and V. N. Manuilov. "Technological gyrotron with low accelerating voltage." Radiophysics and Quantum Electronics 48, no. 10-11 (October 2005): 741–47. http://dx.doi.org/10.1007/s11141-006-0003-7.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Gunell, H., L. Andersson, J. De Keyser, and I. Mann. "Vlasov simulations of trapping and loss of auroral electrons." Annales Geophysicae 33, no. 3 (March 4, 2015): 279–93. http://dx.doi.org/10.5194/angeo-33-279-2015.

Full text

Abstract:

Abstract. The plasma on an auroral field line is simulated using a Vlasov model. In the initial state, the acceleration region extends from one to three Earth radii in altitude with about half of the acceleration voltage concentrated in a stationary double layer at the bottom of this region. A population of electrons is trapped between the double layer and their magnetic mirror points at lower altitudes. A simulation study is carried out to examine the effects of fluctuations in the total accelerating voltage, which may be due to changes in the generator or the load of the auroral current circuit. The electron distribution function on the high potential side of the double layer changes significantly depending on whether the perturbation is toward higher or lower voltages, and therefore measurements of electron distribution functions provide information about the recent history of the voltage. Electron phase space holes are seen as a result of the induced fluctuations. Most of the voltage perturbation is assumed by the double layer. Hysteresis effects in the position of the double layer are observed when the voltage first is lowered and then brought back to its initial value.

APA, Harvard, Vancouver, ISO, and other styles

7

Vaz, O. W., and S. J. Krause. "Low-voltage Scanning Electron Microscopy of polymers." Proceedings, annual meeting, Electron Microscopy Society of America 44 (August 1986): 676–77. http://dx.doi.org/10.1017/s0424820100144772.

Full text

Abstract:

Scanning electron microscopy (SEM) of polymers at routine operating voltages of 15 to 25 keV can lead to beam damage and sample image distortion due to charging. These problems may be avoided by imaging polymer samples at a “crossover point”, which is located at low accelerating voltages (0.1 to 2.0 keV), where the number of electrons impinging on the sample are equal to the number of outgoing electrons emerging from the sample. This condition permits the polymer surface to remain electrically neutral and prevents image distortion due to “charging” effects. In this research we have examined Teflon (polytetrafluorethylene) samples and studied the effects of accelerating voltage and sample tilting on charging phenomena. We have also determined the approximate position of the “crossover point”.

APA, Harvard, Vancouver, ISO, and other styles

8

Kaneko, Yasuko, Makoto Tokunaga, Kyoko Tanaka, Kimie Atsuzawa, and Masako Nishimura. "Backscattered electron imaging and elemental analysis of rapidly frozen plant cells using variable accelerating voltage." Microscopy 67, no. 2 (January 24, 2018): 125–28. http://dx.doi.org/10.1093/jmicro/dfx133.

Full text

Abstract:

Abstract Rapidly frozen rosemary leaves were observed at variable accelerating voltages in a low-vacuum scanning electron microscope equipped with a cryo transfer system. After water was sublimated from the fractured face of the leaf, distinct backscattered electron (BSE) images were obtained depending on the accelerating voltages applied. At 5 kV, surface cell wall structure was observed, whereas at 10 and 15 kV chloroplasts lining the inside of the cell wall and membrane were visualized. With energy dispersive X-ray microanalysis, elemental information corresponding to the BSE images was obtained. Besides visualization of the structures and elemental composition close to the living state, information on layers at different depths from the surface could be detected by varying the accelerating voltage in this system.

APA, Harvard, Vancouver, ISO, and other styles

9

Zaluzec, Nestor J. "Comparison of experimental and theoretical XEDS k-factors as a function of accelerating voltage." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 2 (August 12, 1990): 460–61. http://dx.doi.org/10.1017/s0424820100135903.

Full text

Abstract:

For nearly fifteen years k-factor measurements have been made by varying the composition of the standards at fixed accelerating voltage and measuring the change in the experimental k-factor with atomic number. From this data a “best model” of the ionization cross-section is frequently proposed for use in quantitative analysis, however it is valid only at that fixed voltage. Few if any studies seek to determine the systematic variation in the k-factor with accelerating voltage. In this paper experimental measurements of the variation in the k-factor as a function of accelerating voltage are reported. With the advent of medium voltage analytical microscopes routinely available to the microscopy community, it becomes essential to understand how the k-factor varies with accelerating voltage in order that errors in quantitative analysis can be avoided should experimental or theoretical k-factors from lower voltage instruments are applied to the medium voltage regime.Electropolished specimens of β-NiAl were studied in a Philips CM30T electron microscope, equipped with a Be-Window Si(Li) detector interfaced to an EDAX 9900 Energy Dispersive Analysis System.

APA, Harvard, Vancouver, ISO, and other styles

10

Chernoff, Don. "The Effect of Gas Type on Beam Scatter." Microscopy Today 6, no. 7 (September 1998): 12–13. http://dx.doi.org/10.1017/s1551929500068619.

Full text

Abstract:

Last month I addressed the phenomena of beam scatter in the environmental and low vacuum SEM. In that article I covered how beam scatter is affected by chamber pressure, working distance, and accelerating voltage. To briefly summarize, beam scatter becomes worse at higher chamber pressure, longer working distance, and lower accelerating voltages. As the beam scatters, electrons strike the sample some distance away from the primary beam and as a result, generate X-rays from unwanted areas of the sample. It is advantageous for the analyst to keep beam scatter to a minimum to reduce the generation of these X-ray signals. Under conditions of high chamber pressure, long working distance, and low accelerating voltage, it is possible for electrons from the beam to strike the sample on the order of a millimeter or more from the primary beam.

APA, Harvard, Vancouver, ISO, and other styles

11

Yao, N., C. Harrison, D. H. Adamson, M. Park, P. Chaikin, and R. A. Register. "Sampling Depth Controlled by Accelerating Voltage in a Low Voltage SEM." Microscopy and Microanalysis 3, S2 (August 1997): 1241–42. http://dx.doi.org/10.1017/s143192760001309x.

Full text

Abstract:

A fundamental new pathway to a basic understanding of nanostructured composite thin films has been recently afforded by advances in both high brightness field emission electron source and electron optics in the SEM. The key advantages of controlling the incident electron beam at low energies (< 5 keV) for surface imaging has been largely focused on goals such as the reduction of sample charging and minimization of macroscopic radiation damage. In this paper, we present a new opportunity to obtain sampling depth information by controlling the incident electron beam energy. One of the major factors which determines the contrast seen in SEM images is the interaction of the incident electron beam with the solid. As a result of this interaction, the secondary electron yield is proportional to the stopping power of the electron as described by the Bethe penetration depth,where dE/dl is the stopping power of incident electron with energy Einc and Emin is some suitable lower energy limit for the interaction.

APA, Harvard, Vancouver, ISO, and other styles

12

Norioka, S., T. Miyokawa, S. Goto, T. Niikura, and S. Sakurai. "Field emission SEM with wide operating voltage range." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 976–77. http://dx.doi.org/10.1017/s0424820100106946.

Full text

Abstract:

A newly developed conical anode field emission electron gun (FE-GUN)has been installed on the JSM-840F Scanning Electron Microscope (SEM). The cross sectional view of the column is shown in Fig. 1. The gun is usable at a wide accelerating voltage range from 0.5 kV to 40 kV, and is suitable for general purpose SEMs. The gun can be used within the virtual source range even at an extract voltage as high as 7 kV and an accelerating voltage as low as 0.5 kV. The extract voltage can be raised up to 7 kV even when the emitter tip radius becomes larger after repeated flashing for smoothing the emitter tip surface. This allows elongation of the emitter life.With the FE-GUN, since the electron source (virtual source) moves with accelerating voltage change, an image may disappear due to the deviation of the electron probe from the optical axis when the accelerating voltage is changed.

APA, Harvard, Vancouver, ISO, and other styles

13

Johnson, Matthew T., Ian M. Anderson, Jim Bentley, and C. Barry Carter. "Low-voltage EDS of magnesium ferrite Dendrites in a FEG-SEM." Proceedings, annual meeting, Electron Microscopy Society of America 54 (August 11, 1996): 478–79. http://dx.doi.org/10.1017/s0424820100164854.

Full text

Abstract:

Energy-dispersive X-ray spectrometry (EDS) performed at low (≤ 5 kV) accelerating voltages in the SEM has the potential for providing quantitative microanalytical information with a spatial resolution of ∼100 nm. In the present work, EDS analyses were performed on magnesium ferrite spinel [(MgxFe1−x)Fe2O4] dendrites embedded in a MgO matrix, as shown in Fig. 1. spatial resolution of X-ray microanalysis at conventional accelerating voltages is insufficient for the quantitative analysis of these dendrites, which have widths of the order of a few hundred nanometers, without deconvolution of contributions from the MgO matrix. However, Monte Carlo simulations indicate that the interaction volume for MgFe2O4 is ∼150 nm at 3 kV accelerating voltage and therefore sufficient to analyze the dendrites without matrix contributions.Single-crystal {001}-oriented MgO was reacted with hematite (Fe2O3) powder for 6 h at 1450°C in air and furnace cooled. The specimen was then cleaved to expose a clean cross-section suitable for microanalysis.

APA, Harvard, Vancouver, ISO, and other styles

14

Krause, S. J., W. W. Adams, S. Kumar, T. Reilly, and T. Suziki. "Low-voltage, high-resolution scanning electron microscopy of polymers." Proceedings, annual meeting, Electron Microscopy Society of America 45 (August 1987): 466–67. http://dx.doi.org/10.1017/s0424820100127037.

Full text

Abstract:

Scanning electron microscopy (SEM) of polymers at routine operating voltages of 15 to 25 keV can lead to beam damage and sample image distortion due to charging. Imaging polymer samples with low accelerating voltages (0.1 to 2.0 keV), at or near the “crossover point”, can reduce beam damage, eliminate charging, and improve contrast of surface detail. However, at low voltage, beam brightness is reduced and image resolution is degraded due to chromatic aberration. A new generation of instruments has improved brightness at low voltages, but a typical SEM with a tungsten hairpin filament will have a resolution limit of about 100nm at 1keV. Recently, a new field emission gun (FEG) SEM, the Hitachi S900, was introduced with a reported resolution of 0.8nm at 30keV and 5nm at 1keV. In this research we are reporting the results of imaging coated and uncoated polymer samples at accelerating voltages between 1keV and 30keV in a tungsten hairpin SEM and in the Hitachi S900 FEG SEM.

APA, Harvard, Vancouver, ISO, and other styles

15

Bell, David C., Christopher J. Russo, and Gerd Benner. "Sub-Ångstrom Low-Voltage Performance of a Monochromated, Aberration-Corrected Transmission Electron Microscope." Microscopy and Microanalysis 16, no. 4 (July 2, 2010): 386–92. http://dx.doi.org/10.1017/s1431927610093670.

Full text

Abstract:

AbstractLowering the electron energy in the transmission electron microscope allows for a significant improvement in contrast of light elements and reduces knock-on damage for most materials. If low-voltage electron microscopes are defined as those with accelerating voltages below 100 kV, the introduction of aberration correctors and monochromators to the electron microscope column enables Ångstrom-level resolution, which was previously reserved for higher voltage instruments. Decreasing electron energy has three important advantages: (1) knock-on damage is lower, which is critically important for sensitive materials such as graphene and carbon nanotubes; (2) cross sections for electron-energy-loss spectroscopy increase, improving signal-to-noise for chemical analysis; (3) elastic scattering cross sections increase, improving contrast in high-resolution, zero-loss images. The results presented indicate that decreasing the acceleration voltage from 200 kV to 80 kV in a monochromated, aberration-corrected microscope enhances the contrast while retaining sub-Ångstrom resolution. These improvements in low-voltage performance are expected to produce many new results and enable a wealth of new experiments in materials science.

APA, Harvard, Vancouver, ISO, and other styles

16

Blanford, Christopher F., and C. Barry Carter. "Electron Radiation Damage of MCM-41 and Related Materials." Microscopy and Microanalysis 9, no. 3 (May 23, 2003): 245–63. http://dx.doi.org/10.1017/s1431927603030447.

Full text

Abstract:

The article compares the relative stability of MCM-41 and related mesoporous materials in electron beam at an accelerating voltage of 100–300 kV. The work encountered in electron microscopy presents a comparison with similar research that has been carried out on nonporous and microporous silicates, especially α-quartz and zeolite Y. The trends in stability are analyzed, classifying the effects of sample preparation, organic and inorganic moieties, and electron accelerating voltage on beam stability. A higher synthesis temperature, the use of an acid catalyst in the synthesis, and the presence of additional organic or inorganic material within the channels were all found to stabilize these materials. The dose required to completely disrupt the structure increased with accelerating voltage for nearly all samples, suggesting a primarily radiolytic damage mechanism. The exception, MCM-41 containing nanometer-sized titania particles in its channels, was found to be almost insensitive to accelerating voltage.

APA, Harvard, Vancouver, ISO, and other styles

17

Yoshida, Kaname, and Yukichi Sasaki. "Optimal accelerating voltage for HRTEM imaging of zeolite." Microscopy 62, no. 3 (December 14, 2012): 369–75. http://dx.doi.org/10.1093/jmicro/dfs087.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Steinmetz, D. R., and S. Zaefferer. "Towards ultrahigh resolution EBSD by low accelerating voltage." Materials Science and Technology 26, no. 6 (June 2010): 640–45. http://dx.doi.org/10.1179/026708309x12506933873828.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Miyokawa, T., H. Kazumori, S. Nakagawa, and C. Nielsen. "Ultra-high resolution SEMI-in-lens type FE-SEM, JSM-6320F, with strong magnetic-field lens with built-in secondary-electron detector." Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 484–85. http://dx.doi.org/10.1017/s0424820100170153.

Full text

Abstract:

We have developed a strongly excited objective lens with a built-in secondary electron detector to provide ultra-high resolution images with high quality at low to medium accelerating voltages. The JSM-6320F is a scanning electron microscope (FE-SEM) equipped with this lens and an incident beam divergence angle control lens (ACL).The objective lens is so strongly excited as to have peak axial Magnetic flux density near the specimen surface (Fig. 1). Since the speciien is located below the objective lens, a large speciien can be accomodated. The working distance (WD) with respect to the accelerating voltage is limited due to the magnetic saturation of the lens (Fig.2). The aberrations of this lens are much smaller than those of a conventional one. The spherical aberration coefficient (Cs) is approximately 1/20 and the chromatic aberration coefficient (Cc) is 1/10. for accelerating voltages below 5kV. At the medium range of accelerating voltages (5∼15kV). Cs is 1/10 and Cc is 1/7. Typical values are Cs-1.lmm. Cc=l. 5mm at WD=2mm. and Cs=3.lmm. Cc=2.9 mm at WD=5mm. This makes the lens ideal for taking ultra-high resolution images at low to medium accelerating voltages.

APA, Harvard, Vancouver, ISO, and other styles

20

DEVYATKOV, V. N., N. N. KOVAL, P. M. SCHANIN, V. P. GRIGORYEV, and T. V. KOVAL. "Generation and propagation of high-current low-energy electron beams." Laser and Particle Beams 21, no. 2 (April 2003): 243–48. http://dx.doi.org/10.1017/s026303460321212x.

Full text

Abstract:

High-current electron beams with a current density of up to 100 A/cm2 generated by a plasma-cathode gas-filled diode at low accelerating voltages are studied. Two types of gas discharges are used to produce plasma in the cathode. With glow and arc discharges, beam currents of up to 150 A and 400 A, respectively, have been obtained at an accelerating voltage of 16 kV and at a pressure of 1–3·10−2 Pa in the acceleration gap. The ions resulting from ionization of gas molecules by electrons of the beam neutralize the beam charge. The charge-neutralized electron beam almost without losses is transported over a distance of 30 cm in a drift channel which is in the axial magnetic field induced by Helmholtz coils. The results of calculations for the motion of electrons of the charge-neutralized beam with and without axial external field are presented and compared with those of experiments.

APA, Harvard, Vancouver, ISO, and other styles

21

Munroe, P. R., and I. Baker. "Effect of accelerating voltage on planar and axial channeling in ordered intermetallic compounds." Journal of Materials Research 7, no. 8 (August 1992): 2119–25. http://dx.doi.org/10.1557/jmr.1992.2119.

Full text

Abstract:

The ternary site occupancy of two alloys, vanadium in NiAl + V and hafnium in nickel-rich, boron doped Ni3Al + Hf, was determined by ALCHEMI, or atom location by channeling enhanced microanalysis. Vanadium exhibited a preference for the aluminum sublattice in NiAl, and hafnium preferentially occupied the aluminum sites in Ni3Al. Spectra were acquired over a range of accelerating voltages from 80 kV to 200 kV. Delocalization effects were observed to increase as the accelerating voltage increased, which thus reduces the accuracy of the ALCHEMI data. For NiAl + V, both planar and axial channeling were performed, and delocalization effects were greater for axial channeling, further reducing the accuracy of the ALCHEMI data.

APA, Harvard, Vancouver, ISO, and other styles

22

Zeng, Xiaomei, Vasiliy Pelenovich, Bin Xing, Rakhim Rakhimov, Wenbin Zuo, Alexander Tolstogouzov, Chuansheng Liu, Dejun Fu, and Xiangheng Xiao. "Formation of nanoripples on ZnO flat substrates and nanorods by gas cluster ion bombardment." Beilstein Journal of Nanotechnology 11 (February 24, 2020): 383–90. http://dx.doi.org/10.3762/bjnano.11.29.

Full text

Abstract:

In the present study Ar+ cluster ions accelerated by voltages in the range of 5–10 kV are used to irradiate single crystal ZnO substrates and nanorods to fabricate self-assembled surface nanoripple arrays. The ripple formation is observed when the incidence angle of the cluster beam is in the range of 30–70°. The influence of incidence angle, accelerating voltage, and fluence on the ripple formation is studied. Wavelength and height of the nanoripples increase with increasing accelerating voltage and fluence for both targets. The nanoripples formed on the flat substrates remind of aeolian sand ripples. The ripples formed at high ion fluences on the nanorod facets resemble well-ordered parallel steps or ribs. The more ordered ripple formation on nanorods can be associated with the confinement of the nanorod facets in comparison with the quasi-infinite surface of the flat substrates.

APA, Harvard, Vancouver, ISO, and other styles

23

Oikawa, T., Y. Bando, J. Hosoi, Y. Kokubo, and M. Naruse. "Electron Energy Loss Spectroscopy in a 400kV Transmission Electron Microscope." Proceedings, annual meeting, Electron Microscopy Society of America 43 (August 1985): 412–13. http://dx.doi.org/10.1017/s042482010011893x.

Full text

Abstract:

Electron energy loss spectroscopy (EELS) is a powerful technique to investigate the “electron and atom interaction in specimens.” EELS, as an elementary analysis tool, has the following advantages in a higher accelerating voltage transmission electron microscope (TEM):1)Multiple scattering disturbance decreases with increasing accelerating voltage, because the mean free path of plasmon scattering decreases.2)The signal background ratio (S/B) increases with increasing accelerating voltage, because the effective cut-off angle increases.This report introduces our newly developed electron energy analyzer, the ASEA40, used for the JEM-4000EX 400kV TEM, and presents experimental results that verify its advantages.Fig.1 shows the block diagram of the ASEA40 attached to the JEM-4000EX with the ASID40 and the computer of the EDS system.

APA, Harvard, Vancouver, ISO, and other styles

24

Taminger, Karen M., Robert A. Hafley, and Marcia S. Domack. "Evolution and Control of 2219 Aluminium Microstructural Features through Electron Beam Freeform Fabrication." Materials Science Forum 519-521 (July 2006): 1297–302. http://dx.doi.org/10.4028/www.scientific.net/msf.519-521.1297.

Full text

Abstract:

Electron beam freeform fabrication (EBF3) is a new layer-additive process that has been developed for near-net shape fabrication of complex structures. EBF3 uses an electron beam to create a molten pool on the surface of a substrate. Wire is fed into the molten pool and the part translated with respect to the beam to build up a 3-dimensional structure one layer at a time. Unlike many other freeform fabrication processes, the energy coupling of the electron beam is extremely well suited to processing of aluminum alloys. The layer-additive nature of the EBF3 process results in a tortuous thermal path producing complex microstructures including: small homogeneous equiaxed grains; dendritic growth contained within larger grains; and/or pervasive dendritic formation in the interpass regions of the deposits. Several process control variables contribute to the formation of these different microstructures, including translation speed, wire feed rate, beam current and accelerating voltage. In electron beam processing, higher accelerating voltages embed the energy deeper below the surface of the substrate. Two EBF3 systems have been established at NASA Langley, one with a low-voltage (10-30kV) and the other a high-voltage (30-60 kV) electron beam gun. Aluminum alloy 2219 was processed over a range of different variables to explore the design space and correlate the resultant microstructures with the processing parameters. This report is specifically exploring the impact of accelerating voltage. Of particular interest is correlating energy to the resultant material characteristics to determine the potential of achieving microstructural control through precise management of the heat flux and cooling rates during deposition.

APA, Harvard, Vancouver, ISO, and other styles

25

Newbury, Dale E. "Diagnostics for Assessing Spectral Quality for X-Ray Microanalysis in Low Voltage and Variable Pressure Scanning Electron Microscopy." Microscopy and Microanalysis 7, S2 (August 2001): 702–3. http://dx.doi.org/10.1017/s1431927600029585.

Full text

Abstract:

There is increasing interest in performing x-ray microanalysis of uncoated insulators while operating in unconventional SEM operating modes such as “low voltage” scanning electron microscopy (LVSEM), where the accelerating voltage is ≤ 5 kV and the pressure is low (<10-4 Pa), or variable pressure environmental SEM (VP-ESEM), where a selected gas is maintained at pressures in the range of 1 Pa -1000 Pa. LVSEM and VP-ESEM as microscopy techniques have proven to be extremely successful for imaging uncoated insulators through various charge dissipation mechanisms that are not available under conventional SEM operating conditions (accelerating voltage ≥ 10 kV and pressure < 10-3 Pa). in LVSEM, surface charging of insulators can often be controlled by careful choice of the accelerating voltage, sample tilt, and scan rate, while in VP-ESEM the charged species in the relatively dense gas (ions, secondary electrons) form a self-neutralizing plasma to provide an additional route for discharging the specimen.

APA, Harvard, Vancouver, ISO, and other styles

26

Robinson, V. N. E. "Improving the signal-to-noise ratio of backscattered electron detectors at low beam accelerating voltages." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 362–63. http://dx.doi.org/10.1017/s0424820100086118.

Full text

Abstract:

At high beam accelerating voltages, >5kV, backscattered electron (BSE) detectors rely upon the energy of the BSEs to generate the signal. At low beam accelerating voltages, BSEs do not have sufficient energy to generate a strong signal. This is further compounded because the electrons lose energy penetrating through a thin metal film, which is a dead layer on the surface of the detector. Noise bottleneck considerations1show that the bottleneck for the detection of low energy BSEs, is the signal generated when they impinge upon the detector. Consequently, the signal has to be enhanced before it is amplified. One method of achieving this is to use a multi-channel plate detector. Another is to increase the energy of the BSEs, prior to them impinging upon the detector. This can be acheived by accelerating the BSEs. after they emerge from the specimen, through the application of a positive voltage to the surface of the detector.

APA, Harvard, Vancouver, ISO, and other styles

27

McSwiggen, P., N. Mori, T. Ohta, and C. Nielsen. "Low Accelerating Voltage, X-ray Microanalysis: Benefits and Challenges." Microscopy and Microanalysis 18, S2 (July 2012): 1042–43. http://dx.doi.org/10.1017/s1431927612007064.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Ohye, Toshimi, Yoshiki Uchikawa, Chiaki Morita, and Hiroshi Shimoyama. "Aberrations of Accelerating Tube for High-Voltage Electron Microscope." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 1 (August 12, 1990): 194–95. http://dx.doi.org/10.1017/s0424820100179725.

Full text

Abstract:

The accelerating tube (AT) which accelerates electrons up to a desired energy also functions as an electrostatic lens, In the present paper, numerical calculations were conducted on the electron optical characteristics including the spherical aberration of the AT for the high voltage electron microscope. Several electron optical problems arising from a combination of the AT with a thermionic electron gun (TEG) or a field emission gun (FEG) were studied.<Estimation of aberration for AT lens> The AT consists of 34 electrodes with the inner diameter of 3.3 cm and has the overall length of 142.3 cm (Fig.l). The voltage Va is applied between the cathode and the final electrode of the AT. The initial energy of the electron incident to the AT is eVo, where Vo is the anode voltage of the electron gun mounted on the AT. The electric field inside the AT was calculated using the surface charge method. The ray tracing was carried out on the basis of the relativistic paraxial ray equation, and the cardinal elements of the AT lens were obtained.

APA, Harvard, Vancouver, ISO, and other styles

29

McSwiggen, Peter. "Low Accelerating Voltage X-ray Microanalysis - Strategies and challenges." Microscopy and Microanalysis 21, S3 (August 2015): 679–80. http://dx.doi.org/10.1017/s1431927615004195.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Vovchenko, E. D., A. A. Isaev, K. I. Kozlovskij, A. E. Shikanov, and E. Ya Shkolnikov. "An accelerating voltage generator for compact pulsed neutron sources." Instruments and Experimental Techniques 60, no. 3 (May 2017): 362–66. http://dx.doi.org/10.1134/s0020441217030150.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Cheng, Heyong, Shuli Tang, Tingyuan Yang, Shiqing Xu, and Xin Yan. "Accelerating Electrochemical Reactions in a Voltage‐Controlled Interfacial Microreactor." Angewandte Chemie 132, no. 45 (September 2020): 20034–39. http://dx.doi.org/10.1002/ange.202007736.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Cheng, Heyong, Shuli Tang, Tingyuan Yang, Shiqing Xu, and Xin Yan. "Accelerating Electrochemical Reactions in a Voltage‐Controlled Interfacial Microreactor." Angewandte Chemie International Edition 59, no. 45 (September 2020): 19862–67. http://dx.doi.org/10.1002/anie.202007736.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Robinson, V. N. E. "Factors Affecting the Performance of Backscattered Electron Detectors at Low Beam Accelerating Voltages in SEM." Microscopy and Microanalysis 4, S2 (July 1998): 252–53. http://dx.doi.org/10.1017/s1431927600021383.

Full text

Abstract:

The use of backscattered electron (BSE) imaging in low voltage scanning electron microscopy (SEM) has increased over the past few years. This appears to be due to several factors including improved performance of SEMs at low voltages, reduced beam penetration, more reliable metrology, improved atomic number (Z) contrast information (for low Z) and reduced charging artefacts over secondary electron (SE) imaging. Understanding the factors involved in low voltage BSE detection may assist in improving the information attainable.It has been shown that the signal Sdet from a BSE detector, for EB ≫ Ew is given bywhere η is the BSE yield, Ω is the solid angle subtended by the detector to the specimen, D is the internal conversion efficiency of the detector, EB is beam accelerating voltage, Ew is the energy barrier of the dead layer on the detector's surface, IB is the beam current, F(Z) and F(Ω) are functions which take into account the variation of BSE energy with atomic number Z and collection angle respectively.

APA, Harvard, Vancouver, ISO, and other styles

34

Tzolov, Marian B., Nicholas C. Barbi, Christopher T. Bowser, and Owen Healy. "First-Surface Scintillator for Low Accelerating Voltage Scanning Electron Microscopy (SEM) Imaging." Microscopy and Microanalysis 24, no. 5 (October 2018): 488–96. http://dx.doi.org/10.1017/s1431927618015027.

Full text

Abstract:

AbstractHighly luminescent thin films of zinc tungstate (ZT) have been deposited on top of conventional scintillators (Yttrium Aluminum Perovskite, Yttrium Aluminum Garnet) for electron detection in order to replace the need for a top conducting layer, such as indium tin oxide (ITO) or aluminum, which is non-scintillating and electron absorbing. Such conventional conducting layers serve the single purpose of eliminating electrical charge build-up on the scintillator. The ZT film also eliminates charging, which has been verified by measuring the Duane–Hunt limit and electron emission versus accelerating voltage. The luminescent nature of the ZT film ensures effective detection of low energy electrons from the very top surface of the structure ZT/scintillator, which we call “first-surfacescintillator”. The cathodoluminescence has been measured directly with a photodetector and spectrally resolved at different accelerating voltages. All results demonstrate the extended range of operation of the first-surface scintillator, while the conventional scintillators with a top ITO layer decline below 5 kV and have practically no output below 2 kV. Scintillators of different types were integrated in a detection system for backscattered electrons (BSE). The quality of the image at high accelerating voltages is comparable with the conventional scintillator and commercial BSE detector, while the image quality at 1 kV from the first-surface scintillator is superior.

APA, Harvard, Vancouver, ISO, and other styles

35

Sawyer, Linda C., and Marjorie Jamieson. "Combined low-voltage and field-emission SEM of polymers." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 334–35. http://dx.doi.org/10.1017/s0424820100153646.

Full text

Abstract:

Scanning electron microscopy (SEM) of polymers has been a challenge during the past two decades as the conditions required for maximum resolution in the SEM are coincident with conditions which result in maximum beam damage of the specimens. The accelerating voltage requirement for best detail using a tungsten thermionic source is typically about 20 kV, a voltage at which polymers exhibit mass loss, shrinkage and other changes while only providing minimal surface detail. Lower voltages, which produce better surface detail do not provide enough brightness to reveal the details required. The last decade has seen the use of lanthanum hexaboride thermionic sources which have higher brightness and smaller interaction volumes, permitting operation at lower voltages with minimal beam damage and better surface detail due to decreased depth penetration with increased signal to noise. Thus low voltage SEM (LVSEM) is a method used for structure-property studies of polymers.

APA, Harvard, Vancouver, ISO, and other styles

36

Singh, Nagendra Pratap, S. A. Shivashankar, and Rudra Pratap. "Defect Driven Emission from ZnO Nano Rods Synthesized by Fast Microwave Irradiation Method for Optoelectronic Applications." MRS Proceedings 1633 (2014): 75–80. http://dx.doi.org/10.1557/opl.2014.254.

Full text

Abstract:

ABSTRACTBecause of its large direct band gap of 3.37 eV and high exciton binding energy (∼60 meV), which can lead to efficient excitonic emission at room temperature and above, ZnO nanostructures in the würtzite polymorph are an ideal choice for electronic and optoelectronic applications. Some of the important parameters in this regard are free carrier concentration, doping compensation, minority carrier lifetime, and luminescence efficiency, which are directly or indirectly related to the defects that, in turn, depend on the method of synthesis. We report the synthesis of undoped ZnO nanorods through microwave irradiation of an aqueous solution of zinc acetate dehydrate [Zn(CH3COO)2. 2H2O] and KOH, with zinc acetate dihydrate acting as both the precursor to ZnO and as a self-capping agent. Upon exposure of the solution to microwaves in a domestic oven, ZnO nanorods 1.5 µm -3 µm and 80 nm in diameter are formed in minutes. The ZnO structures have been characterised in detail by X-ray diffraction (XRD), selective area electron diffraction (SAED) and high-resolution scanning and transmission microscopy, which reveal that each nanorod is single-crystalline. Optical characteristics of the nanorods were investigated through photoluminescence (PL) and cathodoluminescence (CL). These measurements reveal that defect state-induced emission is prominent, with a broad greenish yellow emission. CL measurements made on a number of individual nanorods at different accelerating voltages for the electrons show CL intensity increases with increasing accelerating voltage. A red shift is observed in the CL spectra as the accelerating voltage is raised, implying that emission due to oxygen vacancies dominates under these conditions and that interstitial sites can be controlled with the accelerating voltage of the electron beam. Time-resolved fluorescence (TRFL) measurements yield a life time (τ) of 9.9 picoseconds, indicating that ZnO nanorods synthesized by the present process are excellent candidates for optoelectronic devices.

APA, Harvard, Vancouver, ISO, and other styles

37

Chen, Delphic, and Jui-Chao Kuo. "The Effect of Atomic Mass on the Physical Spatial Resolution in EBSD." Microscopy and Microanalysis 19, S5 (August 2013): 4–7. http://dx.doi.org/10.1017/s143192761301221x.

Full text

Abstract:

AbstractIn this study, bicrystals of silver (Ag) and aluminum (Al) were used to investigate the physical spatial resolution of the electron backscatter diffraction system combining a digital image correlation method. Furthermore, the effect of the accelerating voltage and probe current was investigated on the physical spatial resolution of the lateral and longitudinal resolutions for Ag and Al, respectively. The lateral and longitudinal resolutions show high dependency on the accelerating voltage for a low atomic mass material of Al, In addition, these are almost independent of the accelerating voltage for a high atomic mass material of Ag. Moreover, the probe current does not play any role on both the lateral and longitudinal resolutions. The best lateral resolutions for Al and Ag are 40.5 and 12.1 nm at 10 kV and 1 nA, respectively. The best longitudinal resolutions of 23.2 and 80 nm were obtained at 10 kV and 1 nA for Al and Ag, respectively.

APA, Harvard, Vancouver, ISO, and other styles

38

Sikora, Jarosław, Bartosz Kania, and Janusz Mroczka. "Thermionic Electron Beam Current and Accelerating Voltage Controller for Gas Ion Sources." Sensors 21, no. 8 (April 20, 2021): 2878. http://dx.doi.org/10.3390/s21082878.

Full text

Abstract:

Thermionic emission sources are key components of electron impact gas ion sources used in measuring instruments, such as mass spectrometers, ionization gauges, and apparatus for ionization cross-section measurements. The repeatability of the measurements taken with such instruments depends on the stability of the ion current, which is a function, among other things, of the electron beam current and electron accelerating voltage. In this paper, a laboratory thermionic electron beam current and accelerating voltage controller is presented, based on digital algorithm implementation. The average value of the percentage standard deviation of the emission current is 0.021%, and the maximum electron accelerating voltage change versus the emission current is smaller than 0.011% in the full operating range of the emission current. Its application as a trap current or emission current-regulated ion source power supply could be useful in many measuring instruments, such as in microelectromechanical system (MEMS) mass spectrometers as universal gas sensors, where a stable emission current and electron energy are needed.

APA, Harvard, Vancouver, ISO, and other styles

39

Postek, Michael T., William J. Keery, and Nolan V. Frederick. "Low-Profile Microchannel-Plate Electron Detector System for SEM." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 1 (August 12, 1990): 378–79. http://dx.doi.org/10.1017/s0424820100180641.

Full text

Abstract:

One main impetus of present-day scanning electron microscopy is in the low accelerating voltage mode. This mode of operation is useful for nondestructive inspection especially in the on-line inspection and metrology of semiconductor samples. Today, the majority of the scanning electron microscopes used in nondestructive inspection utilize the standard Ever-hart/Thornley (E/T) detector or a modification of this detector as the main detection system. The E/T detector although extremely efficient, suffers from poor signal to noise ratio at low accelerating voltages. This type of detector also suffers from alignment difficulties especially where linewidth measurement for semiconductor applications is concerned because of the uneven distribution of the collection field which is possible, especially if the detector is not located in a plane of symmetry of the specimen and electron beam. These limitations and others have recently led investigators to reconsider the design of secondary electron detection systems especially for low accelerating voltage and metrological applications.A unique situation developed at the National Institute of Standards and Technology (NIST) where a high efficiency electron detector with an exceptionally low profile was needed for the highly customized scanning electron microscope based metrology instrument under development. This instrument incorporates a large laser interferometer stage in the sample chamber which is used for traceability to the national length standard. The large interferometer stage and the restrictive size and shape of the specimen chamber required the development of a lower-profile electron detector than the standard E/T detector and one which does not interfere with the stage motions and interferometry. It was decided that, since the microchan-nel-plate-type electron detector fulfilled the fundamental requirements imposed by the space restrictions, and since this type of detector is also highly efficient at low accelerating voltages, this type of detector system would be used.

APA, Harvard, Vancouver, ISO, and other styles

40

Shen, Yitian, Jingchao Xu, Yongsheng Zhang, Yongzhe Wang, Jimei Zhang, Baojun Yu, Yi Zeng, and Hong Miao. "Spatial Resolutions of On-Axis and Off-Axis Transmission Kikuchi Diffraction Methods." Applied Sciences 9, no. 21 (October 23, 2019): 4478. http://dx.doi.org/10.3390/app9214478.

Full text

Abstract:

Spatial resolution is one of the key factors in orientation microscopy, as it determines the accuracy of grain size investigation and phase identification. We determined the spatial resolutions of on-axis and off-axis transmission Kikuchi diffraction (TKD) methods by calculating correlation coefficients using only the effective parts of on-axis and off-axis transmission Kikuchi patterns. During the calculation, we used average filtering to evaluate the spatial resolution more accurately. The spatial resolutions of both on-axis and off-axis TKD methods were determined in the same scanning electron microscope at different accelerating voltages and specimen thicknesses. The spatial resolution of the on-axis TKD was higher than that of the off-axis TKD at the same parameters. Furthermore, with an increase in accelerating voltage or a decrease in specimen thickness, the spatial resolutions of the two configurations could be significantly improved, from tens of nanometers to below 10 nm. At a voltage of 30 kV and sample thickness of 74 nm, both on-axis and off-axis TKD methods exhibited the highest resolutions of 6.2 and 9.7 nm, respectively.

APA, Harvard, Vancouver, ISO, and other styles

41

Postek, Michael T. "Low accelerating voltage SEM imaging and metrology using backscattered electrons." Review of Scientific Instruments 61, no. 12 (December 1990): 3750–54. http://dx.doi.org/10.1063/1.1141548.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Isakozawa, S., H. Kobayashi, T. Ohashi, M. Tomita, and S. Kamimura. "Development of a New TEM With an Image Rotation System." Proceedings, annual meeting, Electron Microscopy Society of America 43 (August 1985): 140–41. http://dx.doi.org/10.1017/s0424820100117704.

Full text

Abstract:

We have developed a new 125KV TEM (Fig. 1). It incorporates an electron gun operable up to 125KV, 3-stage illumination lens system, and 5-stage imaging lens system. Microprocessors are used to control the high voltage, electron optics and vacuum system.In the high voltage system, accelerating voltage is variable from 10KV to 125KV with increments of 100V/step. In the low voltage operation at 10KV and 25KV,the anode to wehnelt distance is automatically controlled for optimum gun brightness. Filament and bias voltage supplies are also precisely regulated to give stable emission currents at all accelerating voltages.Imaging lens system is free of image rotation during magnification change from 100x to 500,000x. In addition, a new image rotation system is built in. This image rotation system utilizes the individual lens data such as rotation angle, focal length, etc. When a required image rotation angle is given, the computer determines excitation condition of each lens for a selected magnification.

APA, Harvard, Vancouver, ISO, and other styles

43

Shimoyama, H., C. Morita, S. Arai, N. Yokoi, K. Miyauchi, T. Onai, I. Matsui, T. Katsuta, and Y. Enomoto. "Development of Field Emission Gun for High Voltage Electron Microscope." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 1 (August 12, 1990): 604–5. http://dx.doi.org/10.1017/s0424820100181786.

Full text

Abstract:

For the last few years we have been developing a field emission (FE) gun system for our high voltage electron microscope (HVEM) H-1250 ST (maximum accelerating voltage of 1.25 MV) at Nagoya University, in order to attain much higher level of performance of the instrument and to exploit further extended field of application. In the first stage of the project during the period from 1986 to 1987, the FE gun system had been mounted on the top of the accelerating tube, and successfully been operated at the accelerating voltage of 1 MV for the first time pin the world. The operation was very stable and high resolution images for both scanning transmission electron microscopy (STEM) and conventional transmission electron microscopy (CTEM) modes were possible at this stage. At the same time, however, several practical problems related to incorporating the FE gun into the HVEM were made clear. Since then several important modifications on instrumentation and electronics have been made and the project is now at the second stage. In this paper a brief outline of the FE gun system developed for our HVEM is described especially from the view point of instrumentation and electronics.

APA, Harvard, Vancouver, ISO, and other styles

44

Rose, H. "New Feasible Concepts of Aberration Correction for Realizing High-Resolution Electron Microscopes." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 1 (August 12, 1990): 202–3. http://dx.doi.org/10.1017/s0424820100179762.

Full text

Abstract:

The imaging performance of the light optical lens systems has reached such a degree of perfection that nowadays numerical apertures of about 1 can be utilized. Compared to this state of development the objective lenses of electron microscopes are rather poor allowing at most usable apertures somewhat smaller than 10-2 . This severe shortcoming is due to the unavoidable axial chromatic and spherical aberration of rotationally symmetric electron lenses employed so far in all electron microscopes.The resolution of such electron microscopes can only be improved by increasing the accelerating voltage which shortens the electron wave length. Unfortunately, this procedure is rather ineffective because the achievable gain in resolution is only proportional to λ1/4 for a fixed magnetic field strength determined by the magnetic saturation of the pole pieces. Moreover, increasing the acceleration voltage results in deleterious knock-on processes and in extreme difficulties to stabilize the high voltage. Last not least the cost increase exponentially with voltage.

APA, Harvard, Vancouver, ISO, and other styles

45

Soglasnov, V. A. "Difference and similarity in physics of millisecond and normal pulsars." International Astronomical Union Colloquium 177 (2000): 237–38. http://dx.doi.org/10.1017/s025292110005956x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Han, Bei Bei, Dong Ying Ju, Susumu Sato, and Hui Jun Zhao. "Preparation, Characterization and Tribological Properties of Diamond-Like Carbon Film on AZ31 Magnesium Alloy." Key Engineering Materials 804 (May 2019): 69–74. http://dx.doi.org/10.4028/www.scientific.net/kem.804.69.

Full text

Abstract:

In this study, DLC films were deposited using IBED with various CH4/H2 ratio, gas flow rates and accelerating voltages. The composition and mechanical properties of the DLC coatings were characterized using SEM, Raman spectroscopy and nanoindentor. The tribological properties of the coating were also investigated using a frictional surface microscope with an in situ observation system and friction force measurements. The DLC films were characterized by a lower ID/IG, higher hardness, and improved tribological properties when deposited at a lower accelerating voltage (6 kV). At the CH4/H2 ratio of 1:99 and 6 sccm/6 kV, minimum ID/IG values of 0.62, relatively low friction coefficient of 0.12 , and a maximum hardness of 4056 HV were attained respectively.

APA, Harvard, Vancouver, ISO, and other styles

47

Pan, Q. F., and Q. Liu. "Poole–Frenkel Emission Saturation and Its Effects on Time-to-Failure in Ta-Ta2O5-MnO2 Capacitors." Advances in Materials Science and Engineering 2019 (December 31, 2019): 1–9. http://dx.doi.org/10.1155/2019/1690378.

Full text

Abstract:

I-V characterization of Ta-Ta2O5-MnO2 capacitors was investigated at different temperatures, and Poole–Frenkel (PF) emission saturation was experimentally observed. Under the saturation voltage, the I-V curves at different temperature converged, and the temperature dependency was vanished. Above the saturation voltage, the leakage current was decreasing as the temperature increased. In order to evaluate the effects of saturation voltages (VS) on time-to-failure (TTF) of the capacitors, VS were first determined at +2°C and +25°C, then voltage accelerating tests were conducted at 85°C under 1.6 times of rated voltage. The distribution of VS and TTF of the samples were plotted and compared. It was shown that samples with lower saturation voltage failed earlier in the distribution of time-dependent dielectric breakdown. Comparing conventional methods for evaluating the quality of tantalum capacitors by measuring the leakage current at elevated temperature, the nondestructive measurement of saturation voltage at +2°C and +25°C may provide a novel and practicing approach tool to screening out capacitors with defected Ta2O5 layers.

APA, Harvard, Vancouver, ISO, and other styles

48

Mesyats, G. A., A. G. Reutova, K. A. Sharypov, V. G. Shpak, S. A. Shunailov, and M. I. Yalandin. "On the observed energy of runaway electron beams in air." Laser and Particle Beams 29, no. 4 (December 2011): 425–35. http://dx.doi.org/10.1017/s0263034611000541.

Full text

Abstract:

AbstractExperiments with an air electrode gap have been performed where the current/charge of a picosecond beam of runaway electrons was measured over a wide range (up to four orders of magnitude) downstream of the absorbing foil filters. Measurements and calculations have made it possible to refer the beam current to the rise time of the accelerating voltage pulse to within picoseconds. It has been shown that, in contrast to a widespread belief, the runaway electron energies achieved are no greater than those corresponding to the mode of free acceleration of electrons in a nonstationary, highly nonuniform electric field induced by the cathode voltage. The experimental data agree with predictions of a numerical model that describes free acceleration of particles. It has been confirmed that the magnitude of the critical electric field that is necessary for electrons to go into the mode of continuous acceleration of electrons in atmospheric air corresponds to classical notions.

APA, Harvard, Vancouver, ISO, and other styles

49

Huang, Ji Peng, Gang Liu, and Shuang Qiao. "Simulation Research of Deuterium and Tritium Ions Motion in Accelerating Electric Field for Neutron Tube." Applied Mechanics and Materials 538 (April 2014): 62–67. http://dx.doi.org/10.4028/www.scientific.net/amm.538.62.

Full text

Abstract:

The model of neutron tube accelerating system was established to research what the effect of neutron tube accelerating gap, voltage and size of accelerating electrode on trajectory of deuterium tritium ion with finite element simulation technology. Some useful conclusions obtained from the simulation results provide the basis for optimizing the neutron tube structure and parameter, which can make neutron yields of 50-mm-diameter tube in the order of 109 n/s and the stability is not more than 2%.

APA, Harvard, Vancouver, ISO, and other styles

50

Cochran, Raymond F. "Characterization of the low accelerating voltage performance of a microchannel plate based detector system for scanning microscopy." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 364–65. http://dx.doi.org/10.1017/s042482010008612x.

Full text

Abstract:

The Galileo SEM2000 microchannel plate (MCP) detector collects onaxis symmetrical secondary electron images at accelerating voltages as low as 200 eV and beam currents less than 5 picoamps. Symmetrical images are particularly useful in metrology and for viewing features that are shielded by topology from an off-axis detector. Backscatter images from the same on-axis orientation can be obtained at accelerating voltages below 500 eV and beam currents less than 10 picoamps.The ability to image secondary and backscattered electrons in the same orientation, together with extremely high detection efficiency for low energy electrons make it a valuable tool for direct analysis of beam-sensitive or dielectric samples. Additional topographic enhancement can be obtained by A-B signal processing at accelerating voltages as low as 200 eV.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Accelerating voltage'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles