scholarly journals Using circular polarization to test the composition and dynamics of astrophysical particle accelerators

2020 ◽  
Vol 102 (12) ◽  
Author(s):  
Céline Bœhm ◽  
Céline Degrande ◽  
Jakub Scholtz ◽  
Aaron C. Vincent
Keyword(s):  
Circular Polarization ◽  
Particle Accelerators

Specimen Preparation of Near Surface Ion Irradiated Samples

1985 ◽  
Vol 43 ◽  
pp. 170-171
Author(s):  
K. F. Russell ◽  
L. L. Horton
Keyword(s):  
Radiation Damage ◽  
Heavy Ions ◽  
Target Material ◽  
Metal Alloys ◽  
Specimen Surface ◽  
Specimen Preparation ◽  
Particle Accelerators ◽  
Near Surface ◽  
Graaff Accelerator ◽  
Van De Graaff

Beams of heavy ions from particle accelerators are used to produce radiation damage in metal alloys. The damaged layer extends several microns below the surface of the specimen with the maximum damage and depth dependent upon the energy of the ions, type of ions, and target material. Using 4 MeV heavy ions from a Van de Graaff accelerator causes peak damage approximately 1 μm below the specimen surface. To study this area, it is necessary to remove a thickness of approximately 1 μm of damaged metal from the surface (referred to as “sectioning“) and to electropolish this region to electron transparency from the unirradiated surface (referred to as “backthinning“). We have developed electropolishing techniques to obtain electron transparent regions at any depth below the surface of a standard TEM disk. These techniques may be applied wherever TEM information is needed at a specific subsurface position.

Topology Optimization of Superconducting Electromagnets for Particle Accelerators

2019 ◽  
Vol 139 (9) ◽  
pp. 568-575
Author(s):  
Yusuke Sakamoto ◽  
Daisuke Ishizuka ◽  
Tetsuya Matsuda ◽  
Kazuhiro Izui ◽  
Shinji Nishiwaki
Keyword(s):  
Topology Optimization ◽  
Particle Accelerators

HOW THE MEDIAN S-BAND CIRCULAR POLARIZATION RATIO OF KILOMETER-SCALE CRATERS EVOLVES WITH TIME ON THE LUNAR MARIA

2018 ◽  
Author(s):  
Caleb I. Fassett ◽  
◽  
Isabel R. King ◽  
Cole A. Nypaver ◽  
Bradley J. Thomson
Keyword(s):  
Circular Polarization ◽  
Polarization Ratio ◽  
Lunar Maria

A Broadband Circularly Polarized Cross-slotted Patch Antenna with Horizontal Meandered Strip (HMS)

Frequenz ◽  
2020 ◽  
Vol 74 (5-6) ◽  
pp. 191-199
Author(s):  
M. K. Verma ◽  
Binod K. Kanaujia ◽  
J. P. Saini ◽  
Padam S. Saini
Keyword(s):  
Circular Polarization ◽  
Patch Antenna ◽  
Impedance Matching ◽  
Axial Ratio ◽  
Impedance Bandwidth ◽  
Radiation Patterns ◽  
Circularly Polarized ◽  
Feeding Technique

AbstractA broadband circularly polarized slotted square patch antenna with horizontal meandered strip (HMS) is presented and studied. The HMS feeding technique provides the good impedance matching and broadside symmetrical radiation patterns. A set of cross asymmetrical slots are etched on the radiating patch to realize the circular polarization. An electrically small stub is added on the edge of the antenna for further improvement in performance. Measured 10-dB impedance bandwidth (IBW) and 3-dB axial ratio bandwidth (ARBW) of the proposed antenna are 32.31 % (3.14–4.35 GHz) and 20.91 % (3.34–4.12 GHz), respectively. The gain of the antenna is varied from 3.5 to 4.86dBi within 3-dB ARBW. Measured results matched well with the simulated results.

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