Performance of the drift chamber beta-ray momentum analyzer for double beta decay experiments
Performance of the drift chamber beta-ray momentum analyzer for double beta decay experiments
复制标题
双β衰变实验漂移室β射线动量分析仪的性能
DOI：
10.1093/ptep/ptx091
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发表时间：
2017
影响因子：
3.5
通讯作者：
Tam
中科院分区：
文献类型：
--
作者：
Ishihara N.;Ohama T.;Yamada Y.;Kato Y.;Inagaki T.;Iwai G.;Iwase H.;Kawai M.;Kondou Y.;Makida Y.;Takahashi K.;Ujiie N.;Tanaka K.;Tonooka M.;Hamatsu R.;Ishikawa T.;Igarashi H.;Ito T.;Kakizaki M.;Kakuno H.;Kitamura S.;Sumiyoshi T.;Yoshioka T.;Ishizuka T.;Tam
中微子物理学中最重要的问题之一是中微子是马约拉纳粒子还是狄拉克粒子。如果中微子具有马约拉纳性质，则无中微子双β衰变（）肯定会发生。另一方面，有一种理论认为，无中微子四重β衰变（）是可能的，允许轻子数违反四个单位，即使中微子具有狄拉克性质。由于理论上两者的半衰期预计都很长，因此探测器必须具有出色的背景消除能力。我们一直在 KEK 开发一系列电子动量分析仪，称为漂移室 β 射线分析仪 (DCBA)，用于双 β 衰变实验。 DCBA 由检测带电粒子轨迹的漂移室和提供均匀磁场的超导螺线管组成。由于动量接受范围为 0.5–3.5 MeV/，因此很容易消除背景粒子，如 α 粒子、质子和 μ 子，这些粒子由于质量大而具有更高的动量。粒子识别特性和 3D 位置确定功能是搜索和事件的强大工具。在本文中，我们描述了 DCBA 的性能以及探测器构建过程的细节。
One of the most important problems in neutrino physics is whether neutrinos are Majorana particles or Dirac ones. If a neutrino has a Majorana nature, neutrinoless double beta decay () certainly takes place. On the other hand, there is a theory in which neutrinoless quadruple beta decay () is possible, allowing for lepton number violation by four units, even if a neutrino has a Dirac nature. Since the half-lives of bothandare theoretically expected to be very long, detectors have to have an excellent capability to eliminate backgrounds. We have been developing a series of electron momentum analyzers called the drift chamber beta-ray analyzer (DCBA) at KEK for double beta decay experiments. DCBA consists of drift chambers detecting charged particle tracks, and a superconducting solenoid serving a uniform magnetic field. Since the momentum acceptance is in the region of 0.5–3.5 MeV/, it is easy to eliminate background particles like alpha particles, protons, and muons, which have much higher momenta because of their large masses. The particle identification property and the 3D position determination capability are powerful tools to search forandevents. In this article, we describe the performance of DCBA as well as the details of the detector construction processes.