Evaluation of a back-illuminated solid state detector with thin dead layer for super heavy element research

Abstract

The precise energy measurement of charged particles using a silicon semiconductor detector (SSD) is very important in studies of the characteristics of superheavy elements (SHEs). It is necessary to evaluate the dead layer thickness of the SSD to measure the recoil energy of charged particles, such as SHEs, and α particles or fission fragments that are emitted upon the successive decay from the SHEs. Since the energy resolution of the SSD depends on the thickness of the dead layer, a back-illuminated SSD with a thin dead layer has been introduced for SHE research. To evaluate the dead layer thickness of the SSD, energy spectra were first investigated by irradiating 241Am α particles at incident angles of 0° and 45° for two types of SSD. The dead layer thicknesses of the SSDs were deduced by a computer simulation using the particle and heavy ion transport code system (PHITS).