Performance test of a lead-glass counter for the J-PARC E36 experiment

The J-PARC E36 experiment will search for a violation of lepton universality by a precise measurement of the ratio of the kaon decay widths . Charged particles will be identified by the combination of three independent systems: a lead-glass Cherenkov counter, an aerogel Cherenkov counter, and a time-of-flight measurement. The performance of the lead-glass Cherenkov counter was investigated with e+, μ+, and π+ beams in the relevant momentum region from the decays. By using a polyethylene degrader to slow down the beam momentum in front of the lead-glass block, we succeeded in reducing the muon mis-identification probability down to 5% while maintaining a high e+ detection efficiency of 98%.

Y. Miyazaki, S. Shimizu, S. Bianchin, C. Djalali, D. Gill, J. Jiang, M. Hasinoff, K. Horie, Y. Igarashi, J. Imazato, A. Ivashkin, M. Kohl, R. Narikawa, R. Pywell, S. Strauch, M. Tabata, A. Toyoda, H. Yamazaki, T. Yoshioka
Journal Reference: 
Nucl. Inst. Meth. in Phys. Res. A 779 (2015) 13–17