The Applicability of Ultrasonic Oxygen Deficiency Hazard Detectors in the LHC Accelerator Tunnel

The Large Hadron Collider (LHC), will contain about 96 tonnes of high-density helium, mostly located in the underground components of the LHC machine. Some of potential LHC cryogenic system failures might be followed by helium discharge to the tunnel and potential decrease of the oxygen concentration below the safety level of 18% cannot be excluded. A novel concept for oxygen deficiency detection can be based on measurements of sound velocity in the atmosphere. The paper presents the test results of ultrasonic ODH detection prototype system in radiation environment similar to that predicted for the LHC.