{"title":"Estimation of Bonner sphere cross-talking with Monte Carlo method and spectrometer calibration with 241Am-Be neutron source","authors":"Hai Wan, Luying Yang, Xiaofei Jiang","doi":"10.1016/j.nima.2024.170071","DOIUrl":null,"url":null,"abstract":"<div><div>There are usually two kinds of experiment methods for neutron spectrum measurement by Bonner sphere spectrometer (BSS). The first is to use only one Bonner sphere (BS) at a time to complete the neutron experiment by repeated measurements; The other is to measure multiple Bonner spheres (BSs) together, and this multi-sphere simultaneous measurement method can complete the neutron experiment only once. The single sphere measurement method cannot guarantee that the measurement environment is completely consistent every time, which leads to inevitable measurement errors. The multi-sphere simultaneous measurement method can ensure the same experimental environment for each sphere, but there will be cross-talking. This paper studies the influence of cross-talking on BSS. Firstly, we use Geant4 to simulate the corresponding neutron response function with and without cross-talking, and analyze the error between the two neutron response functions. Secondly, the neutron count of <figure><img></figure> neutron source experiment is simulated. Considering that the BSS is close to the floor, the neutron counting error of BS with and without cross-talking and floor scattering is calculated. Finally, we actually measure the <figure><img></figure> neutron source using a BSS and obtain 8 neutron counts. The spectrum of <figure><img></figure> neutron source is obtained by calibrating the influence of cross-talking. The results show that the scattered neutrons which affect the count of BS are mainly the primary scattered neutrons, which account for more than 90% of all scattered neutrons. The scattered neutrons mainly affect the neutron response function of the large BS in the high energy domain and the small BS in the low energy domain. The cross-talking has a great influence on the neutron count of large and small BS, while the floor scattering has a great influence only on the small BS. The <figure><img></figure> neutron spectrum obtained by calibrated neutron counts is more accurate than that obtained by the original experiment counts. Especially in the range of 1<span><math><mo>∼</mo></math></span>5 MeV, the calibrated <figure><img></figure> neutron spectrum is much closer to the international standard spectrum. The mean square error (RMSE) of calibrated <figure><img></figure> neutron spectrum is reduced by 3.86%. In this paper, by analyzing the influence of cross-talking, the neutron count of BSS is calibrated, and the accuracy of <figure><img></figure> neutron spectrum is improved, which provides a strong basis for unfolding neutron spectrum.</div></div>","PeriodicalId":19359,"journal":{"name":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","volume":"1071 ","pages":"Article 170071"},"PeriodicalIF":1.5000,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment","FirstCategoryId":"101","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0168900224009975","RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"INSTRUMENTS & INSTRUMENTATION","Score":null,"Total":0}
引用次数: 0
Abstract
There are usually two kinds of experiment methods for neutron spectrum measurement by Bonner sphere spectrometer (BSS). The first is to use only one Bonner sphere (BS) at a time to complete the neutron experiment by repeated measurements; The other is to measure multiple Bonner spheres (BSs) together, and this multi-sphere simultaneous measurement method can complete the neutron experiment only once. The single sphere measurement method cannot guarantee that the measurement environment is completely consistent every time, which leads to inevitable measurement errors. The multi-sphere simultaneous measurement method can ensure the same experimental environment for each sphere, but there will be cross-talking. This paper studies the influence of cross-talking on BSS. Firstly, we use Geant4 to simulate the corresponding neutron response function with and without cross-talking, and analyze the error between the two neutron response functions. Secondly, the neutron count of neutron source experiment is simulated. Considering that the BSS is close to the floor, the neutron counting error of BS with and without cross-talking and floor scattering is calculated. Finally, we actually measure the neutron source using a BSS and obtain 8 neutron counts. The spectrum of neutron source is obtained by calibrating the influence of cross-talking. The results show that the scattered neutrons which affect the count of BS are mainly the primary scattered neutrons, which account for more than 90% of all scattered neutrons. The scattered neutrons mainly affect the neutron response function of the large BS in the high energy domain and the small BS in the low energy domain. The cross-talking has a great influence on the neutron count of large and small BS, while the floor scattering has a great influence only on the small BS. The neutron spectrum obtained by calibrated neutron counts is more accurate than that obtained by the original experiment counts. Especially in the range of 15 MeV, the calibrated neutron spectrum is much closer to the international standard spectrum. The mean square error (RMSE) of calibrated neutron spectrum is reduced by 3.86%. In this paper, by analyzing the influence of cross-talking, the neutron count of BSS is calibrated, and the accuracy of neutron spectrum is improved, which provides a strong basis for unfolding neutron spectrum.
期刊介绍：
Section A of Nuclear Instruments and Methods in Physics Research publishes papers on design, manufacturing and performance of scientific instruments with an emphasis on large scale facilities. This includes the development of particle accelerators, ion sources, beam transport systems and target arrangements as well as the use of secondary phenomena such as synchrotron radiation and free electron lasers. It also includes all types of instrumentation for the detection and spectrometry of radiations from high energy processes and nuclear decays, as well as instrumentation for experiments at nuclear reactors. Specialized electronics for nuclear and other types of spectrometry as well as computerization of measurements and control systems in this area also find their place in the A section.
Theoretical as well as experimental papers are accepted.
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