Detection efficiency calculation for photons, electrons and positrons in a well detector. Part II: Analytical model versus simulations

2009 ◽  
Vol 606 (3) ◽  
pp. 501-507 ◽  
Author(s):  
S. Pommé ◽  
G. Sibbens ◽  
T. Vidmar ◽  
J. Camps ◽  
V. Peyres
Keyword(s):  
Analytical Model ◽  
Detection Efficiency ◽  
Efficiency Calculation ◽  
Electrons And Positrons ◽  
Detector Part ◽  
Model Versus ◽  
Well Detector

SIMULATIONS OF EXTENSIVE AIR SHOWERS FOR THE ESTIMATION OF THE NUMBER OF PHOTOELECTRONS OF A SETUP OF P. AUGER FLUORESCENCE DETECTOR

2008 ◽  
Vol 23 (02) ◽  
pp. 259-265
Author(s):  
A. GERANIOS ◽  
E. FOKITIS ◽  
S. MALTEZOS ◽  
K. PATRINOS ◽  
H. ROZAKI-MAVROULI
Keyword(s):  
Detection Efficiency ◽  
Optical Filter ◽  
Angle Of Incidence ◽  
Pixel Detector ◽  
Air Showers ◽  
Fluorescence Detector ◽  
Extensive Air Shower ◽  
Air Shower ◽  
Electrons And Positrons ◽  
Detector Geometry

The efficiency of a pixel detector using optical UV filters is determined in this work. Based on the Auger fluorescence detector geometry, we have calculated the overall efficiency of the pixel detector using an appropriate method that takes into account the particular spectral functions and the dependence on the angle of incidence of the optical filter used. Assuming extensive air shower (EAS) events developed with various inclinations generated by AIRES code, we calculated the number of electrons and positrons produced during the development of the EAS's. The detection efficiency of the pixel detector is taken into account in estimating the recorded signal (number of photoelectrons) for two sets of EAS simulations, corresponding to protons and iron nuclei, as primary particles.

scholarly journals ANALYTICAL MODEL TO ESTIMATE EQUIVALENT DOSE FROM INTERNAL NEUTRONS IN PROTON THERAPY OF CHILDREN WITH INTRACRANIAL TUMORS

2019 ◽  
Vol 183 (4) ◽  
pp. 460-468 ◽  
Author(s):  
Kyle J Gallagher ◽  
Phillip J Taddei
Keyword(s):  
Monte Carlo ◽  
Analytical Model ◽  
Organs At Risk ◽  
Absorbed Dose ◽  
Equivalent Dose ◽  
Computationally Efficient ◽  
Organ Doses ◽  
Field Edge ◽  
Model Versus ◽  
Secondary Neutrons

Abstract This study developed a computationally efficient and easy-to-implement analytical model to estimate the equivalent dose from secondary neutrons originating in the bodies (‘internal neutrons’) of children receiving intracranial proton radiotherapy. A two-term double-Gaussian mathematical model was fit to previously published internal neutron equivalent dose per therapeutic absorbed dose versus distance from the field edge calculated using Monte Carlo simulations. The model was trained using three intracranial proton fields of a 9-year-old girl. The resulting model was tested against two intracranial fields of a 10-year-old boy by comparing the mean doses in organs at risk of a radiogenic cancer estimated by the model versus those previously calculated by Monte Carlo. On average, the model reproduced the internal neutron organ doses in the 10-year-old boy within 13.5% of the Monte Carlo at 3–10 cm from the field edge and within a factor of 2 of the Monte Carlo at 10–20 cm from the field edge. Beyond 20 cm, the model poorly estimated H/DRx, however, the values were very small, at <0.03 mSv Gy−1.

scholarly journals Improved Analytical Model of an Outer Rotor Surface Permanent Magnet Machine for Efficiency Calculation with Thermal Effect

2017 ◽  
Vol 6 (1) ◽  
pp. 34-46 ◽  
Author(s):  
Kesavan Ramakrishnan ◽  
Pietro Romanazzi ◽  
Damir Zarko ◽  
Giampiero Mastinu ◽  
David A. Howey ◽  
...  
Keyword(s):  
Permanent Magnet ◽  
Thermal Effect ◽  
Analytical Model ◽  
Permanent Magnet Machine ◽  
Efficiency Calculation ◽  
Outer Rotor ◽  
Rotor Surface

Fresnel interference in point-projection imaging of purple membrane

1995 ◽  
Vol 53 ◽  
pp. 846-847
Author(s):  
X. Zhang ◽  
J. Spence ◽  
W. Qian ◽  
D. Taylor ◽  
K. Taylor
Keyword(s):  
Detection Efficiency ◽  
Mean Free Path ◽  
Purple Membrane ◽  
Unit Cell Dimension ◽  
Experimental Point ◽  
Membrane Thickness ◽  
Low Energies ◽  
Channel Plate ◽  
Point Projection ◽  
Inelastic Mean Free Path

Experimental point-projection shadow microscope (PPM) images of uncoated, unstained purple membrane (PM, bacteriorhodopsin, a membrane protein from Halobacterium holobium) were obtained recently using 100 volt electrons. The membrane thickness is about 5 nm and the hexagonal unit cell dimension 6 nm. The images show contrast around the edges of small holes, as shown in figure 1. The interior of the film is opaque. Since the inelastic mean free path for 100V electrons in carbon (about 6 Å) is much less than the sample thickness, the question arises that how much, if any, transmission of elastically scattered electrons occurs. A large inelastic contribution is also expected, attenuated by the reduced detection efficiency of the channel plate at low energies. Quantitative experiments using an energy-loss spectrometer are planned. Recently Shedd has shown that at about 100V contrast in PPM images of thin gold films can be explained as Fresnel interference effects between different pinholes in the film, separated by less than the coherence width.

Effect of energy filtering on micro-diffraction in the SEM

1994 ◽  
Vol 52 ◽  
pp. 604-605
Author(s):  
James F. Mancuso ◽  
Leo A. Fama ◽  
William B. Maxwell ◽  
Jerry L. Lehman ◽  
Hasso Weiland ◽  
...  
Keyword(s):  
Detection Efficiency ◽  
Ccd Camera ◽  
High Gain ◽  
Microchannel Plate ◽  
Electrostatic Energy ◽  
Energy Filtering ◽  
Electron Channelling ◽  
Low Energy Electrons ◽  
Low Sensitivity ◽  
Angular Field Of View

Micro-diffraction based crystallography is essential to the design and development of many classes of ‘crafted materials’. Although the scanning electron microscope can provide crystallographic information with high spatial resolution, its current utility is severely limited by the low sensitivity of existing diffraction techniques (ref: Dingley). Previously, Joy showed that energy filtering increased contrast and pattern visibility in electron channelling. This present paper discribes the effect of energy filtering on EBSP sensitivity and backscattered SEM imaging.The EBSP detector consisted of an electron energy filter, a microchannel plate detector, a phosphor screen, optical coupler, and a slow scan CCD camera. The electrostatic energy filter used in this experiment was constructed as a cone with 5 coaxial electrodes. The angular field-of-view of the filter was approximately 38°. The microchannel plate, which was the initial sensing component, had high gain and had 50% to 80% detection efficiency for the low energy electrons that passed through the retarding field filter.

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