Effects of High Intensity Cryogenic Irradiation and Magnetic Field on Temperature Sensors

Four types of commercially available cryogenic thermometers were irradiated by gamma and/or neutron sources. These sensors are the well known rhodium-iron and platinum resistance thermometers, carbon resistance thermometer of TVO type and thin-film germanium resistance sensors; they can operate over the 1.5 K to 350 K range (14 K — for platinum sensor). The radiation source for experiments is the Fast Pulsed Reactor of Frank Laboratory for Neutron Physics, JINR. The total doses were about 1016 n/cm2 and 105 Gy at average energy of the fast neutrons of 1 MeV. The thermometers were calibrated at cryogenic temperatures and irradiated at 290 K, after that the comparison of the new calibration to the old one was made. Then the thermometers were irradiated and calibrated in-situ at 77.4 K. In addition, several tests of the thin-film germanium, platinum and TVO-carbon sensors were performed in the magnetic field. The obtained results are discussed.