Single-hit resolution measurement with MEG II drift chamber prototypes
A. M. Baldini, E. Baracchini, G. Cavoto, M. Cascella, F. Cei, M. Chiappini, G. Chiarello, C. Chiri, S. Dussoni, L. Galli, F. Grancagnolo, M. Grassi, V. Martinel… 展开作者
A. M. Baldini, E. Baracchini, G. Cavoto, M. Cascella, F. Cei, M. Chiappini, G. Chiarello, C. Chiri, S. Dussoni, L. Galli, F. Grancagnolo, M. Grassi, V. Martinelli, D. Nicolò, M. Panareo, A. Pepino, G. Piredda, F. Renga, E. Ripiccini, G. Signorelli, G. F. Tassielli, F. Tenchini, M. Venturini, C. Voena
Drift chambers operated with helium-based gas mixtures represent a common solution for tracking charged particles keeping the material budget in the sensitive volume to a minimum. The drawback of this solution is the worsening of the spatial resolution due to primary ionisation fluctuations, which is a limiting factor for high granularity drift chambers like the MEG II tracker. We report on the measurements performed on three different prototypes of the MEG II drift chamber aimed at determining the achievable single-hit resolution. The prototypes were operated with helium/isobutane gas mixtures and exposed to cosmic rays, electron beams and radioactive sources. Direct measurements of the single hit resolution performed with an external tracker returned a value of 110 $μ$m, consistent with the values obtained with indirect measurements performed with the other prototypes.
Paul Scherrer研究所的MEG实验寻找带电轻子味破坏mu+ -> e+伽马衰变。MEG已经设定了世界上最好的分支比上限：BR<4.2x10^-13@90% C. l。已批准对整个探测器进行升级（MEG II），以大幅提高灵敏度。目前，MEG II正在完成各种探测器的升级，2018年和2019年进行了工程运行和预调试运行。新的正电子跟踪器是一个独特的体积，超轻的He基圆柱形漂移室（CDCH），具有高粒度：9层192平方漂移室，~6-9 mm宽，由~12000根金属丝组成的全立体配置。为了确保漂移单元的静电稳定性，应开发新的布线策略，这是由于高的线密度（12根线/cm ^2）、对线位置的严格精度要求以及线机械张力的均匀性（优于0.5 g）。基本思想是通过在40 um厚的定制线PCB上焊接一组（16或32）线来创建多线框架。多丝框架和PEEK垫片沿半径交替重叠，以在由舵轮形端板的辐条限定的十二个扇区中的每一个中设置适当的单元宽度。尽管组装策略在概念上很简单，但在设定要求的情况下，多线框架的构建需要使用自动布线系统。MEG II CDCH是有史以来第一个以模块化方式设计和建造的圆柱形漂移室，它将允许使用非常少量的材料（1.5x10^-3 X 0）以高效率跟踪动量大于45 MeV/c的正电子。我们描述了CDCH的设计和施工，INFN莱切的布线阶段，电线的选择，它们的机械性能，INF…
Hardware Implementation of a Fast Algorithm for the Reconstruction of Muon Tracks in ATLAS Muon Drift-Tube Chambers for the First-Level Muon Trigger at the HL-LHC
Surface Commissioning and Performance of the sMDT Muon Chambers for the ATLAS HL-LHC Upgrade
University of Michigan（密歇根大学）；Max Planck Institute for Physics（马克斯·普朗克物理研究所）；Tufts University（塔夫茨大学）；Chinese University of Hong Kong（香港中文大学）；Michigan State University（密歇根州立大学）；University of Science and Technology of China（中国科学技术大学）
Performance Evaluation of Straw Tubes with Muon Beams at CERN
University of Michigan（密歇根大学）；Tufts University（塔夫茨大学）；Institute of Nuclear Physics, Almaty（阿拉木图核物理研究所）；Joint Institute for Nuclear Research, Dubna（杜布纳联合核研究所）；University of Florida（佛罗里达大学）；CERN（欧洲核子研究组织）；NRC Kurchatov Institute PNPI（库尔恰托夫国家研究中心普列哈诺夫物理技术研究所）
