Cherenkov detector of 90Sr based on aerogel as radiator

90Sr is a highly radiotoxic fission product, which may pollute the environment following an accident in a nuclear power plant. It is a pure β emitter and thus difficult to detect by standard methods. Recent progress in silica aerogel production, as well as the new multianode photomultiplier tubes (PMTs), offer possibilities for the detection of 90Sr, based on Cherenkov radiation of β particles emitted by its daughter 90Y. An appropriate choice of the aerogel refractive index (produced in the range between 1.005 and 1.06) determines the threshold for Cherenkov radiation and thus separates between higher and lower energy β particles. Multianode PMTs permit the determination of the Cherenkov photon yield, offering additional discrimination. An apparatus was constructed for the detection of the relatively higher energy β particles emitted by 90Y ( E max = 2.28 MeV ) and the detector performance was studied.