Protection of the in-vacuum-operating straw chambers from vacuum penetration

摘要

In the past years, drift chambers with thin-wall tubes (straws) operating in high vacuum (similar to 10(-5) mb) has become to be used in experimental studies of rare decays. Any drift tube of the operating chamber may suffer a mechanical or electrical damage and a subsequent leak. The complete failure of the tube is not excluded either. To protect the chambers against the above damage, we have developed and tested a relatively simple protection system based on uniquely designed energy-independent devices. If air-tightness is broken and gas starts leaking from the tube into the vacuum, they automatically cut off the gas flow on both ends of the damaged tube and disconnect it from the gas supply.