Response of thin NE102A scintillator films to fission fragments

Abstract

The pulse height response of NE102A plastic scintillator films to fragment ions from 252Cf spontaneous fission has been investigated as a function of fragment time-of-flight and film thickness t in the range 1–15 μm. For velocities close to the two peaks in the fragment velocity spectrum and for films of either t ≳ 9 μm or t ≲ 3 μm, an approximately linear relationship between response and fragment velocity is found. For films of thickness 3–6 μm or for fragments from symmetric or highly asymmetric fission. deviations from the linear dependence are observed. The response increases rapidly with film thickness in the range t = 3–6 μm and saturates at t ≳ 9 μm for both light and heavy fragments. The possible role of surface effects in these phenomena is discussed.