Analysis of Dependence of Detector Position on Detected Scatter Distribution in Dedicated Breast SPECT

2014 ◽  
pp. 501-507
Author(s):  
Steve D. Mann ◽  
Jainil P. Shah ◽  
Martin P. Tornai
Keyword(s):  
Detector Position

Effects of Surface-Scanning Detector Position on the Response of a Wireless Magnetoelastic Biosensor

2017 ◽  
Vol 80 (10) ◽  
pp. 1579-1583
Author(s):  
Shin Horikawa ◽  
Songtao Du ◽  
Yuzhe Liu ◽  
Xu Lu ◽  
I-Hsuan Chen ◽  
...  
Keyword(s):  
Surface Scanning ◽  
Detector Position

scholarly journals A simulational study of the indirect-geometry neutron spectrometer BIFROST at the European Spallation Source, from neutron source position to detector position

2021 ◽  
Vol 54 (1) ◽  
pp. 263-279
Author(s):  
M. Klausz ◽  
K. Kanaki ◽  
T. Kittelmann ◽  
R. Toft-Petersen ◽  
J. O. Birk ◽  
...  
Keyword(s):  
Neutron Source ◽  
Neutron Transport ◽  
Rate Capability ◽  
Simulation Software ◽  
Neutron Spectrometer ◽  
Instantaneous Rate ◽  
Simulation Tools ◽  
Detector Position ◽  
Spallation Source ◽  
Incident Rates

The European Spallation Source (ESS) is intended to become the most powerful spallation neutron source in the world and the flagship of neutron science in upcoming decades. The exceptionally high neutron flux will provide unique opportunities for scientific experiments but also set high requirements for the detectors. One of the most challenging aspects is the rate capability and in particular the peak instantaneous rate capability, i.e. the number of neutrons hitting the detector per channel or cm2 at the peak of the neutron pulse. The primary purpose of this paper is to estimate the incident rates that are anticipated for the BIFROST instrument planned for ESS, and also to demonstrate the use of powerful simulation tools for the correct interpretation of neutron transport in crystalline materials. A full simulation model of the instrument from source to detector position, implemented with the use of multiple simulation software packages, is presented. For a single detector tube, instantaneous incident rates with a maximum of 1.7 GHz for a Bragg peak from a single crystal and 0.3 MHz for a vanadium sample are found. This paper also includes the first application of a new pyrolytic graphite model and a comparison of different simulation tools to highlight their strengths and weaknesses.

scholarly journals Determination of an Effective Detector Position for Pulsed-Neutron-Source Alpha Measurement by Time-Dependent Monte Carlo Neutron Transport Simulations

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Sang Hoon Jang ◽  
Hyung Jin Shim
Keyword(s):  
Monte Carlo ◽  
Neutron Source ◽  
Neutron Transport ◽  
Signal Amplitude ◽  
Time Dependent ◽  
Convergence Time ◽  
Simple Method ◽  
Detector Position ◽  
Pulsed Neutron ◽  
Pulsed Neutron Source

A simple method using the time-dependent Monte Carlo (TDMC) neutron transport calculation is presented to determine an effective detector position for the prompt neutron decay constant (α) measurement through the pulsed-neutron-source (PNS) experiment. In the proposed method, the optimum detector position is searched by comparing amplitudes of detector signals at different positions when their α estimates by the slope fitting are converged. The developed method is applied to the Pb-Bi-zoned ADS experimental benchmark at Kyoto University Critical Assembly. The α convergence time estimated by the TDMC PNS simulation agrees well with the experimental results. The α convergence time map and the corresponding signal amplitude map predicted by the developed method show that polyethylene moderator regions adjacent to fuel region are better positions than other candidates for the PNS α measurement.

scholarly journals New tools for calibrating diffraction setups

2020 ◽  
Vol 27 (2) ◽  
pp. 558-566 ◽  
Author(s):  
J. Kieffer ◽  
V. Valls ◽  
N. Blanc ◽  
C. Hennig
Keyword(s):  
User Interface ◽  
Graphical User Interface ◽  
Large Area ◽  
Area Detector ◽  
Detector Position ◽  
Scattering Experiment ◽  
Large Area Detector

New calibration tools in the pyFAI suite for processing scattering experiments acquired with area detectors are presented. These include a new graphical user interface for calibrating the detector position in a scattering experiment performed with a fixed large area detector, as well as a library to be used in Jupyter notebooks for calibrating the motion of a detector on a goniometer arm (or any other moving table) to perform diffraction experiments.

THE REACTION OF DEUTERIUM ATOMS WITH ETHYLENE

1956 ◽  
Vol 34 (8) ◽  
pp. 1061-1073 ◽  
Author(s):  
S. Toby ◽  
H. I. Schiff
Keyword(s):  
Isotopic Composition ◽  
Isothermal Calorimetry ◽  
Reaction Rates ◽  
Recombination Coefficient ◽  
Tungsten Filament ◽  
Hydrogen Atoms ◽  
Atom Concentration ◽  
Metaphosphoric Acid ◽  
Detector Position ◽  
Reactant Flow

Deuterium was dissociated on a hot tungsten filament and the atom concentration measured by isothermal calorimetry. The recombination coefficient of deuterium atoms on a glass surface, coated with metaphosphoric acid, was found to be 3.8 × 10−5, and similar to that found for hydrogen atoms. The reactions of H-atoms and D-atoms with ethylene were found to be very rapid. The effects on the yields of the products and on their isotopic composition of variations of reactant flow rate, atom concentration, pressure, and atom-detector position were studied. The major products were methanes, ethanes, and ethylenes, with minor amounts of propanes and butanes. The methanes were always highly deuterated while the ethanes were slightly deuterated. A mechanism is proposed to explain the observations based on a flow pattern in the reaction zone. The possibility of differences in the reaction rates of variously deuterated intermediates is also discussed.

Efficient Simulation of Secondary Fluorescence Via NIST DTSA-II Monte Carlo

2017 ◽  
Vol 23 (3) ◽  
pp. 618-633 ◽  
Author(s):  
Nicholas W. M. Ritchie
Keyword(s):  
Monte Carlo ◽  
Variance Reduction ◽  
General Purpose ◽  
Physical Models ◽  
Computationally Efficient ◽  
X Ray ◽  
Detector Position ◽  
Reduction Techniques ◽  
Similar Accuracy ◽  
Secondary Fluorescence

AbstractSecondary fluorescence, the final term in the familiar matrix correction triumvirate Z·A·F, is the most challenging for Monte Carlo models to simulate. In fact, only two implementations of Monte Carlo models commonly used to simulate electron probe X-ray spectra can calculate secondary fluorescence—PENEPMA and NIST DTSA-IIa (DTSA-II is discussed herein). These two models share many physical models but there are some important differences in the way each implements X-ray emission including secondary fluorescence. PENEPMA is based on PENELOPE, a general purpose software package for simulation of both relativistic and subrelativistic electron/positron interactions with matter. On the other hand, NIST DTSA-II was designed exclusively for simulation of X-ray spectra generated by subrelativistic electrons. NIST DTSA-II uses variance reduction techniques unsuited to general purpose code. These optimizations help NIST DTSA-II to be orders of magnitude more computationally efficient while retaining detector position sensitivity. Simulations execute in minutes rather than hours and can model differences that result from detector position. Both PENEPMA and NIST DTSA-II are capable of handling complex sample geometries and we will demonstrate that both are of similar accuracy when modeling experimental secondary fluorescence data from the literature.

scholarly journals Detector position estimation for PET scanners

2012 ◽  
Vol 677 ◽  
pp. 74-79 ◽  
Author(s):  
Larry Pierce ◽  
Robert Miyaoka ◽  
Tom Lewellen ◽  
Adam Alessio ◽  
Paul Kinahan
Keyword(s):  
Position Estimation ◽  
Detector Position ◽  
Pet Scanners
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