Belle Cryogenic System Home Page

News (Upper is newer)

Summer maintenance schedule (kek.jp domain only) is available. ('03/06/10)
URL was changed to "http://belle.kek.jp/~phcryo/". ('01/04/11)

Introduction

A cryogenic system of a superconducting solenoid magnet for the BELLE detector system was constructed for the B-factory experiment in 1997 at KEK. The cryogenic system is composed of a medium-size refrigerator with two helium gas tanks, a sub-cooler and a superconducting solenoid magnet. The effective cold mass is 7.9 ton for the magnet only and 1.0 ton for the chimney. The main refrigerator, which had been once used for the QCS system of the TRISTAN experiment in KEK, was proved to maintain refrigeration power of 240 W at 4.4 K with liquid nitrogen precooling in this time too. In steady state, the magnet is cooled by 2-phase forced helium flow. But once the main refrigerator stops due to sudden problems, the cooling method switches to the themo-syphon mode from the chimney during discharging. The all state of cryogenic system are monitored and full-automatically controlled at the central control room with large process controllers. In addition to it, all present state data of the cryogenic system are opened with flow charts in a webpage and all previous data can be referred in the same website easily.