The European Spallation Source (ESS) aspires to be the worlds leading neutron source of the upcoming decades, and sets the scope on replacing 3 He tube detectors where it is reasonably achievable. The Multi-Grid detector, an Ar/CO2-filled proportional chamber based on solid 10B4C converter, is the most potent replacement technology for chopper spectroscopy. This study reproduces in a detailed Geant4 geometry of a neutron scattering instrument the data from the Multi-Grid demonstrator detector, that has been tested for a 1 year period, installed side-by-side to the 3 He tubes at the CNCS instrument at SNS. For the further understanding of the background of the detector, Monte-Carlo simulations were performed, with the ESS Coding Framework, using a Geant4 version extended with NXSG4 and NCrystal. A detailed and realistic model of the prototype was built and was validated via comparison against measured data. With this model, different sources of neutron scattering were determined and studied separately, providing a better understanding of the scattered neutron background. Due to these capabilities the model will be used in the further optimization of the detector, especially for the background reduction via shielding, which will lead to instruments with better signal-to-background ratio by design.
|Title of host publication||2017 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2017 - Conference Proceedings|
|Number of pages||3|
|Publication status||Published - 2018|
|Event||2017 IEEE Nuclear Science Symposium and Medical Imaging Conference - Atlanta, United States|
Duration: 21 Oct 2017 → 28 Oct 2017
|Conference||2017 IEEE Nuclear Science Symposium and Medical Imaging Conference|
|Period||21/10/2017 → 28/10/2017|