Performance of the BETS detector for cosmic ray electrons Original Research Article

Performance of BETS detector as an electron imaging calorimeter was studied by electron and proton beams at CERN-SPS in 1996 and 1997. It is confirmed that the rejection power against proton backgrounds is better than 4 × 10−4 in the energy range between 10 GeV and 100 GeV, the energy resolution ranges 15∼18 %, and the angular resolution is 0°.8∼1°.3. The balloon flights were carried out in 1995, 1997, and 1998 at the Sanriku Balloon Center in Japan. it is demonstrated in the flight data that the performance is adequate for observing electrons with reliable accuracy.