[22p-F308-1~13] 2.1 Detection Devices

▲ [22p-F308-13] The Performance Evaluation of Glass Gas Electron Multiplier Detector with Low Noise Charge Sensitive Preamplifier and Dynamic Time-over-Threshold-Based Readout

〇Moh Hamdan¹, Yuki Mitsuya, Kenji Shimazoe, Hiroyuki Takahashi (1.Tokyo Univ)

Keywords:Gas Electron Multiplier (GEM), Low Noise Charge Sensitive Preamplifier (CSP),, Dynamic Time-over-Threshold (dToT)

The Gas Electron Multiplier (GEM) is a widely used Micro Pattern Gas Detector (MPGD) for several applications such as X-ray imaging, neutron imaging, and Time Projection Chamber (TPC). Recent GEM has a large sensitive area capability with high position resolution due to its finer pitch. To increase the spatial resolution, GEM-based gas detectors are often coupled with electronic anode readout systems of hundreds to thousands of fine pitch channels. A low noise preamplifier is required to couple the detector with an energy resolving readout and DAQ system. On the other hand, reducing the readout scale while maintaining its energy resolving capability is necessary for developing large-scale detectors. Dynamic Time-over-Threshold (dToT)-based readout can have a smaller circuit scale while still providing good linearity performance between analog pulse height and digital pulse width. In this work, we evaluated the basic performance of PEG3C Glass GEM. They have 100 × 100 mm² of sensitive areas. The thickness, hole size, and hole pitch are 680 µm, 170 µm, and 280 µm respectively. Glass GEM chamber was supplied with Ar/CH₄ (95/5) gas in gas flow mode with a flow rate of 100 mL/min and a pressure of 0.1 MPa. A low noise Charge Sensitive Preamplifier (CSP) with ~700 noise electrons has been fabricated and tested for coupling the anode of the Glass GEM chamber with other readout and DAQ systems. The maximum effective gain reached 8800 without severe sparks using difference voltage of G-GEM electrode of 1560 V. The Energy resolution was 17 % at full-width half maximum (FWHM) biased at 8800 gains. GEM performance was also evaluated by connecting the CSP with the dToT and DAQ systems as an initial evaluation of the entire GEM-based detector system. Effective gain, energy resolution, and polarization were evaluated for the entire GEM-based detector system.