Specific luminescence studies of alpha particles in NE-102 scintillator film

Abstract

The specific luminescence ( ΔL/ Δx) of 0.5–8.8 MeV alpha particles from a natural decay source has been measured by using a thin film detector (TFD) consisting of a thin organic scintillator material positioned between and perpendicular to the faces of two photomultiplier tubes. The TFD response, proportional to the specific luminescence, was examined both as a function of the experimentally determined stopping power ( ΔE/ Δx) and the incident alpha particle energy. Alpha particle energies were measured with a solid state detector (SSD). In general the experimental results were consistent with what had been expected on the basis of studies of other light and heavy ions transiting thin films. Of particular interest are the data obtained on alpha particles possessing energies which bracket the kinetic energy corresponding to maximum stopping power. These data are significant in that they confirm the double valuedness of specific luminescence as a function of stopping power for alpha particles. Calculations based on a model of specific luminescence production agree with the measured trends but predict a too rapidly decreasing luminescence at higher energies. The experimental energy loss values obtained are in reasonable agreement with calculated values.