Behavior of 144ch HAPDs for the Belle II Aerogel RICH in the Magnetic Field
We report behavior of Hybrid Avalanche Photon Detectors (HAPDs), which were newly developed for Aerogel Ring Imaging Cherenkov detector (ARICH) counter that will be installed in the endcap region of the Belle II detector, in the magnetic field. Since HAPDs are used in a 1.5 T magnetic field in the Belle II detector, we have tested 520 HAPDs from the mass production in the magnetic field. We observed anomalously large pulses in the magnetic field in many HAPDs. The main adverse effect of these large pulses is the induction of a short dead time of the readout electronics after each pulse. We performed several studies to understand the mechanism generating large pulses.
KeywordsParticle identification Hybrid Avalanche Photo Detector Magnetic field Belle II
- 1.Abe, T., et al.: Belle II Technical Design Report (2010). arxiv:1011.0352 [physics.ins-det] KEK Report 2010-1
- 2.Pestotnik, R., et al.: The aerogel ring imaging Cherenkov system at the Belle II spectrometer. Nucl. Instrum. Methods Phys. Res. A (2018, in press). https://doi.org/10.1016/j.nima.2017.04.043
- 4.Yusa, Y., et al.: Test of the HAPD light sensor for the Belle II Aerogel RICH. Nucl. Instrum. Methods Phys. Res. A (2018, in press). https://doi.org/10.1016/j.nima.2017.02.046
- 6.Chatrchyan, S., et al.: Identification and Filtering of Uncharacteristic Noise in the CMS Hadron Calorimeter (2010). arxiv:0911.4881 [physics.ins-det] CMS PAPER CFT-09-019