24-28 February 2020
Budker Institute of Nuclear Physics
Asia/Novosibirsk timezone

Development of compact micro-pattern gaseous detectors for application to the CEPC digital hadron calorimeter

28 Feb 2020, 10:10
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Contributed Oral Micropattern gas detectors Micropattern gas detectors


Mr Daojin Hong (University of Science and Technology of China)


An imaging hadron calorimeter with digital readout (DHCAL) using the micro-pattern gaseous detector (MPGD) technology is one of the hadron calorimeter options for the Circular Electron Positron Collider (CEPC). The sensitive detector of the CEPC DHCAL is required to be compact and highly efficient for MIPs with low number of hits per MIP track (hit multiplicity). GEM and WELL-THGEM detectors have been investigated as options for the DHCAL sensitive detector. A GEM detector with only two GEM layers (double-GEM) was proposed to make the detector more compact than the usual triple-GEM detector. A 30 cm× 30 cm double- GEM prototype was built with the self-stretching technique to study the performance of the double-GEM detector for application to the CEPC DHCAL. The double-GEM prototype was read out with the Microroc chip that has been developed specifically for the application of MPGDs to DHCALs, and was tested with cosmic-rays. The results of the test show a detection efficiency higher than 95% for MIPs was obtained, and hit multiplicity was about 1.2. However, the double-GEM detector made by the self-stretching technique has a dead area of about 10% at the four edges of the detector, which turned out to be hardly reduced. The WELL-THGEM detector is advantageous to the GEM detector in minimizing the dead area due to its simple assembly without stretching. In addition, it has a more compact structure than the double-GEM detector thanks to use of single-stage gas amplification and no induction gap. A 25 cm× 25 cm resistive WELL-THGEM prototype was developed with the DLC coating and thermal bonding techniques, where the former technique was used to make resistive layers for the prototype and the latter was used to bond the THGEM layer and the anode PCB together. Besides, a fast grounding circuit was designed on the anode to enhance the rate capability of the detector. Preliminary results from tests of the WELL-THGEM with X-rays show the gain of the detector could reach 8000 with a 20% uniformity, and the detector could maintain such a gain when irradiated with 8 keV X-ray at a rate of 300 kHz/cm2. Based on these results, the WELL-THGEM detector looks a promising MPGD as the sensitive detector of the CEPC DHCAL, which merits further studies.

Primary author

Mr Daojin Hong (University of Science and Technology of China)

Presentation Materials