High Pressure Gas Scintillators

Observations of scintillation pulse heights have been made at pressures up to 75 atmospheres in xenon and argon, and in mixtures of nitrogen and xenon, nitrogen and argon, and neon and xenon. Diphenyl stilbene was used as a wavelength shifter. The most salient feature is that in all cases pulse height is approximately independent of pressure at pressures over a few atmospheres. The nitrogen-xenon and neon-xenon mixtures have been used as neutron detectors via the N
¹⁴
(n,p), N
¹⁴
(n,α) and Ne
²⁰
(n,α) reactions. The resolutions achieved, particularly in nitrogen-xenon mixtures (pulse height sometimes down to 1/40 of pure xenon) allow a good estimate to be made of the number of photons detected per unit energy loss in the scintillator.