Feb 21 – 25, 2022
Vienna University of Technology
Europe/Vienna timezone

Vacuum-Compatible Ultra-Thin-Wall Straw Tracker; Detector construction, Thinner straw R&D, and the brand-new graphite-straw development

Feb 23, 2022, 3:15 PM
Vienna University of Technology

Vienna University of Technology

Gusshausstraße 27-29, 1040 Wien
Live Presentation Gaseous Detectors Gaseous Detectors


Hajime Nishiguchi (KEK)


The COMET experiment at J-PARC aims to search for a lepton-flavour violating process of muon to electron conversion, with a branching-ratio sensitivity of 10$^{−17}$, to explore the region predicted by most of theoretical models beyond the Standard Model. The expected signal of this process is mono-energetic 105 MeV single electron. To distinguish such a low energy signal, a material budget of detector is essential since the detection accuracy is primarily limited by multiple scattering.

To realize the required low material detector, a vacuum-compatible ultra-thin-wall straw tracker has been designed, then 20$\mu$-thick Mylar straw with 70nm Al cathode has been developed employing ultrasonic-welding technique. This was reported in VCI2016, and the detector performances such as detection efficiency and intrinsic spacial resolutions were reported in VCI2019. After the previous VCI, a detector construction using this straw was performed. In parallel to this, thinner straw, i.e. 12$\mu$m-thick straw, has been developed with joint collaboration among KEK, JINR and CERN. During this R&D, it was noticed that the current technology cannot achieve much thinner/smaller tubes than the present one. Then, we launched a brand-new project to realize the graphite-textile straw which realizes an extremely low material tracker.

In VCI2022, a brief report on detector construction with 20$\mu$m-thick straw, R&D on 12$\mu$m-thick straw and a brand-new graphite straw will be provided.

Primary experiment COMET

Primary author


Alexander Volkov (Russian Academy of Sciences (RU)) Eitaro Hamada Hans Danielsson (CERN) Mr Junichi Suzuki (KEK) Kazuki Ueno (KEK) Dr Kei Watanabe (Shinshu university) Mr Naoya Kamei (KEK) Nikolozi Tsverava (Georgian Technical University (GE)) Mr Osamu Ohsawa (Shishu university) Satoshi Mihara (KEK) Dr Yoshinori Hashimoto (KEK) Zviadi Tsamalaidze (Georgian Technical University (GE))

Presentation materials