Scintillation Response of CsI(Tl) Crystals to Fission Fragments and EnergyvsRange in Various Materials for Light and Heavy Fission Fragments

A thin CsI(Tl) crystal was used as the phosphor of a scintillation detector of fission fragments. Light and heavy fragments from pile neutron fission of ${\mathrm{U}}^{235}$ were magnetically separated and scintillation pulse heights in CsI(Tl) crystals determined as a function of range in various gases and metals. The relationship between pulse height and fragment energy was found to be linear. Specific fluorescence of fission fragments in the crystal increases monotonically with specific energy loss. Energy vs range curves were obtained for median-mass light and heavy fragments in ${\mathrm{H}}_2$, He, air, A, Al, Ni, and Au.