scholarly journals Low energy dark current collimation system in single-pass linacs

2018 ◽  
Vol 21 (2) ◽  
Author(s):  
S. Bettoni ◽  
P. Craievich ◽  
M. Pedrozzi ◽  
M. Schaer ◽  
L. Stingelin
Keyword(s):  
Dark Current ◽  
Low Energy ◽  
Single Pass ◽  
Collimation System

Large Area Silicon Carbide Photodiode, and Monolithic Readout Design and Fabrication

2016 ◽  
Vol 858 ◽  
pp. 1023-1027
Author(s):  
Akin Akturk ◽  
Brendan Cusack ◽  
Neil Goldsman
Keyword(s):  
Silicon Carbide ◽  
Low Power ◽  
Power Density ◽  
Dark Current ◽  
Low Energy ◽  
Large Area ◽  
Active Pixel Sensor ◽  
Active Pixel ◽  
Deep Ultraviolet ◽  
Ultraviolet Photons

We are in the process of designing and fabricating a very large area (> 4mm2) and extremely low dark current silicon carbide ultraviolet photodiode with a readout circuitry monolithically fabricated on the same die. This is a large area silicon carbide based active pixel sensor (APS), capable of measuring low power density deep ultraviolet photons as well as low energy particles. To this end, we have already fabricated several large area photodiodes with low dark current values and large ultraviolet responsivities. We here report the electrical and optical measured performance of various size photodiodes we have fabricated.

X-RAY COLLIMATOR DESIGN USING MONTE CARLO SIMULATIONS

2013 ◽  
Vol 25 (06) ◽  
pp. 1350054
Author(s):  
Eun Young Han ◽  
Richard Clarkson ◽  
Sunil Sharma ◽  
Peter M. Corry ◽  
Eduardo G. Moros ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Small Animal ◽  
Low Energy ◽  
Aperture Size ◽  
Beam Size ◽  
Dose Distributions ◽  
X Ray ◽  
Collimation System ◽  
Acceptable Agreement ◽  
Ebt2 Film

The purpose of this study was to apply Monte Carlo (MC) based simulations to design a new collimation system to achieve a larger beam size (2 ± 0.1 cm) and tight penumbra (< 1 mm) with a kV X-ray small animal irradiator. The BEAMnrc and DOSXYZnrc MC-based programs were adapted to simulate the system. First the aperture of the primary collimator was expanded until the desired size of the beam was obtained. Subsequently, the beam was trimmed by reducing the aperture size of the secondary collimator in order to eliminate low energy scattered photons and sharpen the penumbra. Finally, the new collimator was constructed and the resultant dose distributions were evaluated with EBT2 film measurements. From the MC computed dose profiles, a 2.1 cm FWHM (1.9 cm width at 95% of the dose) and a sharp penumbra (< 1.0 mm) at 1.0 cm depth in water were obtained. Dose distribution comparisons between the EBT2 film measurements and the MC calculations showed acceptable agreement. MC-based calculation is an effective tool to expedite the creation of new collimator designs and avoid costly machining.

Ultrastructural evaluation of multiple pass low energy versus single pass high energy radio-frequency treatment

2006 ◽  
Vol 38 (2) ◽  
pp. 150-154 ◽  
Author(s):  
David Kist ◽  
A. Jay Burns ◽  
Roth Sanner ◽  
Jeff Counters ◽  
Brian Zelickson
Keyword(s):  
Radio Frequency ◽  
High Energy ◽  
Low Energy ◽  
Single Pass ◽  
Multiple Pass

The LEPTA Facility for Fundamental Studies of Positronium Physics and Positron Spectroscopy

2012 ◽  
Vol 733 ◽  
pp. 291-296 ◽  
Author(s):  
Aleksey A. Sidorin ◽  
Igor Meshkov ◽  
E. Ahmanova ◽  
M. Eseev ◽  
A. Kobets ◽  
...  
Keyword(s):  
Electron Beam ◽  
Storage Ring ◽  
Cooling System ◽  
Positron Beam ◽  
Low Energy ◽  
Electron Cooling ◽  
Positron Energy ◽  
Single Pass ◽  
Positron Spectroscopy

At present time the Low Energy Positron Toroidal Accumulator (LEPTA) at JINR is under commissioning with circulating positron beam. The LEPTA facility is a small positron storage ring equipped with the electron cooling system and positron injector. The maximum positron energy is of 10 keV. The storage ring is aimed for generation of direct fluxes of ortho-positronium (o-Ps), produced in recombination of the positron beam circulating in the ring with single pass cooling electron beam. The project has few goals: annihilation spectroscopy (PAS) to monitoring defects of nanometer sizes in materials as a function of depth managed by the positron energy in a rage of a few eV to 100 keV.

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