Optimization of Ray-tracing Simulations to Confirm Performance of the GP-SANS Instrument at the High-Flux Isotope Reactor

Fuente: arXiv
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Autores principales: Rogers, James M., Frost, Matthew J., DeBeer-Schmitt, Lisa
Formato: Preprint
Publicado: 2024
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author Rogers, James M.
Frost, Matthew J.
DeBeer-Schmitt, Lisa
author_facet Rogers, James M.
Frost, Matthew J.
DeBeer-Schmitt, Lisa
contents The CG-2 beamline at the High Flux Isotope Reactor (HFIR) exhibits a notable discrepancy between observed count rates and the count rates we would expect based on a Monte-Carlo neutron ray-trace simulation. These simulations consistently predict count rates approximately five times greater than those observed in four separate experimental runs involving different instrument configurations. This discrepancy suggests that certain factors are causing losses in measurements that are not adequately accounted for in the simulation, in particular guide reflectivity or misalignment. To investigate these discrepancies, a high-dimensional simulation parameter approach is applied in order to understand the losses. Region of Interest (ROI) groups along the instrument are assigned to different surfaces of the guide components within the simulation. This allows the parameters of those guide components to be varied as a group to minimize the complexity of the search space. The result is an optimization of simulation parameters using an iterative scheme that aims to minimize the difference between experimentally measured count rates and simulated count rates across all tested collimator combinations. This proposed methodology holds the potential to reveal previously unrecognized sources of intensity loss in the CG-2 beamline at HFIR and improve the accuracy of simulations, leading to enhanced understanding and performance of the beamline for various scientific applications.
format Preprint
id arxiv_https___arxiv_org_abs_2404_08890
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Optimization of Ray-tracing Simulations to Confirm Performance of the GP-SANS Instrument at the High-Flux Isotope Reactor
Rogers, James M.
Frost, Matthew J.
DeBeer-Schmitt, Lisa
Instrumentation and Detectors
The CG-2 beamline at the High Flux Isotope Reactor (HFIR) exhibits a notable discrepancy between observed count rates and the count rates we would expect based on a Monte-Carlo neutron ray-trace simulation. These simulations consistently predict count rates approximately five times greater than those observed in four separate experimental runs involving different instrument configurations. This discrepancy suggests that certain factors are causing losses in measurements that are not adequately accounted for in the simulation, in particular guide reflectivity or misalignment. To investigate these discrepancies, a high-dimensional simulation parameter approach is applied in order to understand the losses. Region of Interest (ROI) groups along the instrument are assigned to different surfaces of the guide components within the simulation. This allows the parameters of those guide components to be varied as a group to minimize the complexity of the search space. The result is an optimization of simulation parameters using an iterative scheme that aims to minimize the difference between experimentally measured count rates and simulated count rates across all tested collimator combinations. This proposed methodology holds the potential to reveal previously unrecognized sources of intensity loss in the CG-2 beamline at HFIR and improve the accuracy of simulations, leading to enhanced understanding and performance of the beamline for various scientific applications.
title Optimization of Ray-tracing Simulations to Confirm Performance of the GP-SANS Instrument at the High-Flux Isotope Reactor
topic Instrumentation and Detectors
url https://arxiv.org/abs/2404.08890