Design and construction of the cylindrical drift chamber for the COMET Phase-I experiment

Authors

A. Sato ^a, H. Yoshida ^a ^b, M. Moritsu ^c, X. Jiang ^d ^e, Y. Kuno ^a ^b, H.-B. Li ^d ^e, W.-G. Li ^d ^e ¹, Y. Matsuda ^a, H. Miao ^d ^e, Y. Nakamura ^a, Y. Nakatsugawa ^g, Y. Nakazawa ^h, S. Ohta ^a, K. Okinaka ^a, H. Sakamoto ^a, M.L. Wong ^a ², T.S. Wong ^a, C. Wu ^d ^f, T.-Y. Xing ^d ^e, T. Yamane ^a, Y. Yuan ^d ^e, J. Zhang ^d ^e, Y. Zhang ^d, Z.-K. Zhang ^d ^e

Affiliations

^aDepartment of Physics, Osaka University, 1-1 Machikaneyama, Toyonaka, 560-0043, Osaka, Japan
b Research Center for Nuclear Physics, Osaka University, 10-1 Mihogaoka, Suita, 567-0047, Osaka, Japan
c Department of Physics, Kyushu University, 744 Motooka, Nishi-ku, 819-0395, Fukuoka, Japan
d Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing, China
e University of Chinese Academy of Sciences, 100049, Beijing, China
f Spallation Neutron Source Science Center, 523808, Dongguan, China
g Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-8509, Wakayama, Japan
h KEK, 1-1 Oho, Tsukuba, 305-0801, Ibaraki, Japan

Journal

Published Date

9/30/24

DOI

Abstract

COMET is an experiment at J-PARC that searches for the charged lepton flavor violating process of neutrino-less muon-to-electron conversion ( conversion) in a muonic atom. The COMET Phase-I experiment, which represents the first stage of its staged approach, utilizes the cylindrical drift chamber (CDC) as the main detector to measure the momentum of electrons emitted from conversion in a 1 T magnetic field. The CDC is designed for optimal performance to achieve the best momentum resolution and effectively separate the conversion electron signal from background signals. This design entails adapting He:i-C₄H₁₀ (90:10) as its chamber gas and employing an all-stereo wire configuration. This document provides a comprehensive overview of the CDC detector, encompassing design considerations, mechanical structure, construction methodologies, and results of performance evaluations conducted using cosmic-rays.