Flammable Gas Systems

Hall C uses several flammable gas systems. Most notable are the hydrogen and deuterium flammabe gas systems associated to the cryogenic targets. These systems will be discussed in detail in the specific subsection on the Hall C cryogenic target system. Furthermore, the Gas Handling System (GHS) providing gas for the HMS and SOS drift chambers uses a 50:50 mixture (by volume) of argon and ethane gas. The gas is mixed in a specially-built GHS which passes the mixed gas through an alcohol (isopropanol) bubbler before passing it to the chambers. The gas flow is approximately 300 SCCM. Ethane is a flammable gas and should be treated accordingly. The Hall C gas mixing shed and both detector huts have gas monitors which are sensitive to Ethane gas leaks. If a leak is detected, an alarm will go off in the Hall C Counting House and the main valves for ethane and argon supply in the gas mixing shed will be automatically closed. Argon is supplied in an A-cylinder under high pressure $P \approx$ 2000 PSI. This confined high pressure gas represents a tremendous amount of stored energy. Care should be taken when handling these high-pressure bottles.

Furthermore the Gas Cerenkovs in both HMS and SOS utilize small amounts of gases, typically CO$_2$ or N$_2$ at sub-atmospheric pressure, C$_4$F$_{10}$ or Freon-12 (CCl$_2$F$_2$).