[1] Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA
[2] Univ Liverpool, Liverpool L69 EBX, Merseyside, England
[3] Univ Calif Santa Cruz, Santa Cruz Inst Particle Phys, Santa Cruz, CA 95064 USA
[4] Univ London Queen Mary & Westfield Coll, London E1 4NS, England
[5] Univ Tokyo, Tokyo 1130033, Japan
[6] Hiroshima Univ, Higashihiroshima 7398526, Japan
[7] Hytec Inc, Los Alamos, NM 87544 USA
[8] Hamamatsu Photon, Hamamatsu, Shizuoka 4308587, Japan