Study of scintillation in helium mixed with xenon to develop thermal neutron detectors

We have studied the transfer of luminescence from He to Xe by adding a small amount of Xe to He. Luminescence spectra, scintillation yields and time profiles of the mixture were measured. The He/Xe mixture emitted scintillation photons in the 140-210 nm wavelength region, peaked around 173 nm. The scintillation yields and time profiles were measured using a PMT sensitive to photon wavelengths between 115 and 300 nm. The observed decay time of scintillation in the mixture He/Xe is shorter than that of He2*. The scintillation yield increased with increasing Xe fraction. However, without recombination light it is saturated above a Xe pressure of 0.06 MPa