Ultrasonic helium detectors applied in oxygen deficiency hazard monitor system in radiation environment

Abstract

The prototype ultrasonic sound velocity measuring system was designed and built at Wroclaw University of Technology. The system aims to detect helium release into the air in a quantity that may cause oxygen deficiency hazard (ODH) and is also dedicated to work in radiation conditions. In order to qualify the measuring system to be used in accelerator tunnels, the stability of the readouts and the durability of the ultrasonic transducers and electronics have been investigated in a radiation environment. Two tests were carried out: one at the European Organization for Nuclear Research CERN in Geneva, and another at the Institute of Atomic Energy (IEA) in Otwock-Swierk near Warsaw, Poland. The readouts were very stable and there was no danger of provoking false alarms of ODH. The accumulated doses absorbed by the system correspond to over 10 years of the large hadron collider (LHC) operation. The developed technology can be considered being used in installations where the oxygen deficiency hazard may be a result of helium release into the air, especially in particle accelerators where the measuring system is threatened by ionizing radiation.