Properties of high pressure nitrogen-argon and nitrogen-xenon gas scintillators

Abstract

Investigations of scintillation light output and energy resolution have been made at pressures up to 90 atm in gaseous mixtures of nitrogen with both argon and xenon by stopping of 210Po-alpha particles. In the absence of a wavelength shifter, the N 2Ar mixtures gave a maximum pulse height at a ratio of nitrogen to argon partial pressures r N 2 Ar ≊ 0.2 . However, when using the wavelength shifter diphenyl stilbene (DPS), the measured light output was much larger to lower values of r N 2 Ar , whereas for r N 2 Ar > 0.2 pulse height and energy resolution of the studied N 2Ar mixtures were roughly identical with and without DPS. The N 2Xe gas mixtures exhibited a similar dependence of pulse height and energy resolution to that of the N 2Ar mixtures employing DPS, but the pulse heightwas larger by a factor of about 7. A 40 atm 50% N 2−50% Xe gas scintillator showed an energy resolution ΔE E = 0.25 , while an 80 atm 75% N 2−25% Xe scintillator gave ΔE E = 0.6 . The pulse height from the 80 atm N 2Xe scintillator was smaller by a factor of about 240 than the pulse height from a 20 atm pure Xe gas scintillator, but larger by a factor of about 20 than the pulse height from a 75 atm pure N 2 gas scintillator. The N 2Xe mixtures showed a remarkable increase of light output as the temperature of the gas was decreased.