AI 中文总结
本文测定了4 keV和6 keV反质子在GBAR微通道板探测器表面的背散射概率，未发现背散射证据，设定68%置信水平下上限为14%，该结果对GBAR反氢原子产生截面测定具有重要意义。
AI 中文摘要
人们通常认为，入射到材料表面的反质子会立即与材料的原子核发生湮灭。然而，在几千电子伏特（keV）的动能下，这一假设可能不成立。与低能质子、电子或正电子可从靶上反射类似，反质子在湮灭发生前可能会经历大角度库仑散射，从而表现为从材料表面“背散射”。这一背散射比例在很大程度上是未知的，却是GBAR实验中确定反氢原子产生截面的关键要素。本文测定了4 keV和6 keV反质子在GBAR用于束流成像的微通道板（Micro-Channel Plate）探测器表面发生背散射的概率。研究未发现背散射的证据，并对该概率设定了68%置信水平下14%的上限。同时，本文还探讨了背散射对GBAR实验中参与反氢产生的反质子数量测定的影响。
英文摘要
It is commonly assumed that antiprotons impinging on a material surface annihilate promptly with the nuclei of the material. However, at kinetic energies of a few keV, this assumption may not hold. As with low-energy protons, electrons or positrons that can be reflected from a target, they may undergo large-angle Coulomb scattering before annihilation occurs, thereby appearing to be "backscattered" from the material surface. This backscattering fraction, largely unknown, is a crucial ingredient to the determination of the production cross-section of antihydrogen atoms in the GBAR experiment. This paper presents a determination of the probability that 4 and 6 keV antiprotons backscatter on the surface of a Micro-Channel Plate detector used for beam imaging at GBAR. No evidence for backscattering has been found and an upper limit of 14% at 68% confidence level has been set on this probability. The impact of backscattering on the determination of the number of antiprotons that participate in antihydrogen production in GBAR is also addressed.
Comments16 pages, 13 figures
