Towards a precise measurement of the antihydrogen ground state hyperfine splitting in a beam: the case of in-flight radiative decays
Towards a precise measurement of the antihydrogen ground state hyperfine splitting in a beam: the case of in-flight radiative decays
复制标题
精确测量光束中的反氢基态超精细分裂：飞行中辐射衰变的情况
DOI：
10.1088/0953-4075/48/18/184001
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
E. Widmann
中科院分区：
文献类型：
--
作者：
R. Lundmark;C. Malbrunot;Y. Nagata;B. Radics;C. Sauerzopf;E. Widmann
欧洲核子研究中心反质子减速器（AD）上的ASACUSA反氢装置由一个反氢源（勾形磁铁耦合到正电子源和反质子捕获磁铁）和一个光谱仪光束线组成。在尖点产生后，反氢原子在逃离陷阱时发生衰变，导致其有效磁矩发生变化，从而影响其在光束线中的轨迹。在磁场强度变化的情况下，从尖点的产生点到谱线末端的检测，这些连续的衰变在原则上可以极大地影响精确测量反氢超精细分裂的前景，因为迄今为止可用的反原子数量相对较少。首次模拟了这种背景下反氢衰变的影响。在Geant 4中实现了原子辐射衰变，将最初嵌入Geant 4的粒子跟踪功能扩展到激发原子，并允许研究动态原子特性对轨迹的影响。因此，这个新工具允许通过Geant 4工具包研究粒子-物质相互作用，同时适当考虑所研究对象的原子性质。本文讨论了反氢谱的实现以及对实验灵敏度的影响。
The ASACUSA antihydrogen setup at the CERN Antiproton Decelerator (AD) consists of an antihydrogen source (cusp magnet coupled to a positron source and an antiproton catching magnet) followed by a spectrometer beamline. After production in the cusp, the antihydrogen atoms decay while they escape the trap leading to changes in their effective magnetic moment which in turn affect their trajectories in the beamline. Those sequential decays in the presence of a varying magnetic field strength from their production point in the cusp to their detection at the end of the spectrometer line can in principle greatly affect the prospects for a precision measurement of the antihydrogen hyperfine splitting given the so-far relatively low number of available anti-atoms. The impact of the antihydrogen decay in this context has for the first time been simulated. The implementation of atomic radiative decay has been done in Geant4 to extend the particle tracking capabilities originally embedded in Geant4 to excited atoms, and to allow studies of the effect of dynamic atomic properties on trajectories. This new tool thus allows the study of particle–matter interaction via the Geant4 toolkit while properly taking into account the atomic nature of the object under study. The implementation as well as impacts on the experimental sensitivity for antihydrogen spectroscopy are discussed in this paper.