The ultra light Drift Chamber of the MEG II experiment
The ultra light Drift Chamber of the MEG II experiment
复制标题
MEG II 实验的超轻型漂移室
DOI：
10.1016/j.nima.2019.04.106
复制
发表时间：
2020
影响因子：
1.4
通讯作者：
C. Voena
中科院分区：
文献类型：
--
作者：
A. Baldini;G. Cavoto;F. Cei;M. Chiappini;G. Chiarello;A. Corvaglia;M. Francesconi;L. Galli;F. Grancagnolo;M. Grassi;M. Hildebrandt;M. Meucci;A. Miccoli;D. Nicoló;A. Papa;M. Panareo;C. Pinto;F. Raffaelli;F. Renga;G. Signorelli;G. Tassielli;C. Voena
Paul Scherrer 研究所的 MEG 实验寻找违反 μ+→ e+ γ 衰变的带电轻子味。 MEG 在第一个数据采集阶段就已经确定了世界上最好的分支比上限： BR (μ+→ e+ γ)< 4. 2× 1 0− 13 整个探测器的升级已被批准以获得灵敏度的大幅提高。目前MEG正处于升级阶段，该阶段涉及所有探测器。新型正电子跟踪器是一个高透明度单体积、全立体圆柱形漂移室（CDCH），浸入非均匀纵向B场中，长度为1. 93 m，内半径为17 cm，外半径为30 cm。它由9个同心层组成，分为12个相同的扇区，每扇区有16个漂移单元。单个漂移单元近似正方形，20 μm 镀金 W 传感线被 40 μm 镀银 Al 场线包围，比例为 5:1。当室内充满氦气和异丁烷的气体混合物时，每圈轨道的等效辐射长度约为 1.5 x10− 3 X 0，线总数为 11904 根。由于导线密度较高（12 Wire s∕ cm 2），使用经典的馈通技术作为导线锚固系统很难实现，因此有必要开发新的布线策略。电线的数量和严格的要求要求使用自动系统（接线机器人）来操作接线程序。在不同的漂移室原型上进行了多次测试，暴露在宇宙射线、测试光束和放射源下，以满足空间分辨率小于110μm的要求。在本文中，我们描述了 CDCH 的建设和 2018 年工程运行期间的首次测试。
The MEG experiment at the Paul Scherrer Institute searches for the charged Lepton Flavor Violating μ+→ e+ γ decay. MEG has already determined in a first data taking phase the world best upper limit on the branching ratio: BR (μ+→ e+ γ)< 4. 2× 1 0− 13 An upgrade of the whole detector has been approved to obtain a substantial increase in sensitivity. Currently MEG is in upgrade phases, this phase involves all the detectors. The new positron tracker is a high transparency single volume, fully stereo cylindrical Drift Chamber (CDCH), immersed in a non uniform longitudinal B-field, with length of 1. 93 m, internal radius of 17 cm and external radius of 30 cm. It is composed of 9 concentric layers, divided into 12 identical sector of 16 drift cells. The single drift cell is approximately square, with a 20 μ m gold plated W sense wire surrounded by 40 μ m silver plated Al field wires in a ratio of 5: 1. The total number of wires amounts to 11904 for an equivalent radiation length per track turn of about 1.5 x10− 3 X 0 when the chamber is filled with a gas mixture of helium and iso-butane. Due to the high wire density (12 w i r e s∕ cm 2), the use of the classical feed-through technique as wire anchoring system could hardly be implemented and therefore it was necessary to develop new wiring strategies. The number of wires and the stringent requirements impose the use of an automatic system (wiring robot) to operate the wiring procedures. Several tests have been performed in different prototypes of the drift chamber, exposed to cosmic rays, test beams and radioactive sources, to fulfill the requirement on the spatial resolution to be less than 110 μ m. In this paper we describe the CDCH construction and the first tests during the 2018 Engineering Run.
使用MEG II实验液氙伽马射线探测器时间校准计数器评估时间分辨率
DOI：
--
发表时间：
2022
期刊：
影响因子：
--
作者：
Akabayashi;Hideo;Shimpei Taguchi;Mirka Zvedelikova;松下彩華
通讯作者：
松下彩華