Propagation of modulated electron and X-ray beams through matter and interactions with radio-frequency structures

2018 ◽  
Vol 123 (8) ◽  
pp. 083302 ◽  
Author(s):  
J. R. Harris ◽  
R. B. Miller
2021 ◽  
Vol 11 (15) ◽  
pp. 6990
Author(s):  
Erick Gastellóu ◽  
Godofredo García ◽  
Ana María Herrera ◽  
Crisoforo Morales ◽  
Rafael García ◽  
...  

GaN films doped with Mg or Zn were obtained via radio-frequency magnetron sputtering on silicon substrates at room temperature and used laboratory-prepared targets with Mg-doped or Zn-doped GaN powders. X-ray diffraction patterns showed broadening peaks, which could have been related to the appearance of nano-crystallites with an average of 7 nm. Scanning electron microscopy and transmission electron microscopy showed good adherence to silicon non-native substrate, as well as homogeneity, with a grain size average of 0.14 µm, and 0.16 µm for the GaN films doped with Zn or Mg, respectively. X-ray photo-electron spectroscopy demonstrated the presence of a very small amount of magnesium (2.10 mol%), and zinc (1.15 mol%) with binding energies of 1303.18, and 1024.76 eV, respectively. Photoluminescence spectrum for the Zn-doped GaN films had an emission range from 2.89 to 3.0 eV (429.23–413.50 nm), while Mg-doped GaN films had an energy emission in a blue-violet band with a range from 2.80 to 3.16 eV (443.03–392.56 nm). Raman spectra showed the classical vibration modes A1(TO), E1(TO), and E2(High) for the hexagonal structure of GaN.


Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 373
Author(s):  
Wen-Yen Lin ◽  
Feng-Tsun Chien ◽  
Hsien-Chin Chiu ◽  
Jinn-Kong Sheu ◽  
Kuang-Po Hsueh

Zirconium-doped MgxZn1−xO (Zr-doped MZO) mixed-oxide films were investigated, and the temperature sensitivity of their electric and optical properties was characterized. Zr-doped MZO films were deposited through radio-frequency magnetron sputtering using a 4-inch ZnO/MgO/ZrO2 (75/20/5 wt%) target. Hall measurement, X-ray diffraction (XRD), transmittance, and X-ray photoelectron spectroscopy (XPS) data were obtained. The lowest sheet resistance, highest mobility, and highest concentration were 1.30 × 103 Ω/sq, 4.46 cm2/Vs, and 7.28 × 1019 cm−3, respectively. The XRD spectra of the as-grown and annealed Zr-doped MZO films contained MgxZn1−xO(002) and ZrO2(200) coupled with Mg(OH)2(101) at 34.49°, 34.88°, and 38.017°, respectively. The intensity of the XRD peak near 34.88° decreased with temperature because the films that segregated Zr4+ from ZrO2(200) increased. The absorption edges of the films were at approximately 348 nm under 80% transmittance because of the Mg content. XPS revealed that the amount of Zr4+ increased with the annealing temperature. Zr is a potentially promising double donor, providing up to two extra free electrons per ion when used in place of Zn2+.


2015 ◽  
Vol 107 (8) ◽  
pp. 081606 ◽  
Author(s):  
Matthew J. Highland ◽  
Dillon D. Fong ◽  
Guangxu Ju ◽  
Carol Thompson ◽  
Peter M. Baldo ◽  
...  

2015 ◽  
Vol 833 ◽  
pp. 127-133
Author(s):  
Jie Yu ◽  
Jie Xing ◽  
Xiu Hua Chen ◽  
Wen Hui Ma ◽  
Rui Li ◽  
...  

La0.9Sr0.1Ga0.8Mg0.2O3-δ (LSGM) electrolyte thin films were fabricated on La0.7Sr0.3Cr0.5Mn0.5O2.75 (LSCM) porous anode substrates by Radio Frequency (RF) magnetron sputtering method. The compatibility between LSGM and LSCM was examined. Microstructures of LSGM thin films fabricated were observed by scanning electron microscope (SEM). The effect of substrate temperature on LSGM thin films was clarified by X-ray Diffraction (XRD). Deposition rate increases firstly at the range of 50°C~150°C, and then decreases at the range of 150°C ~300°C. After annealing, perovskite structure with the same growth orientation forms at different substrate temperature. Crystallite size decreases at first, to the minimum point at 150°C, then increases as substrate temperature rises.


Radiology ◽  
1935 ◽  
Vol 24 (3) ◽  
pp. 298-302 ◽  
Author(s):  
Robert S. Stone ◽  
M. Stanley Livingston ◽  
David H. Sloan ◽  
Milton A. Chaffee
Keyword(s):  

2016 ◽  
Vol 44 ◽  
pp. 1660209 ◽  
Author(s):  
M. Santana Leitner ◽  
L. Ge ◽  
Z. Li ◽  
C. Xu ◽  
C. Adolphsen ◽  
...  

The Linac Coherent Light Source II (LCLS-II) will be a hard X-ray Free Electron Laser whose linac can deliver a 1.2 MW CW electron beam with bunch rates up to 1 MHz. To efficiently generate such a high power beam, Super-Conducting Radio-Frequency (SCRF) cavities will be installed in the upstream portion of the existing 3 km Linac at the SLAC National Accelerator Laboratory. The 9-cell niobium cavities will be cooled at 2K inside 35 cryomodules, each containing a string of eight of those cavities followed by a quadrupole. The strong electromagnetic fields in the SCRF cavities will extract electrons from the cavity walls that may be accelerated. Most such dark current will be deposited locally, although some electrons may reach several neighboring cryomodules, gaining substantial energy before they hit a collimator or other aperture. The power deposited by the field emitted electrons and the associated showers may pose radiation and machine protection issues at the cryomodules and also in other areas of the accelerator. Simulation of these effects is therefore crucial for the design of the machine. The in-house code Track3P was used to simulate field emitted electrons from the LCLS-II cavities, and a sophisticated 3D model of the cryomodules including all cavities was written to transport radiation with the Fluka Monte Carlo code, which was linked to Track3P through custom-made routines. This setup was used to compute power deposition in components, prompt and residual radiation fields, and radioisotope inventories.


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