LaBr 3:Ce scintillators for in-beam gamma-ray spectroscopy with fast beams of rare isotopes

Abstract

The scintillator material LaBr 3:Ce, which was discovered in 2001, has grown in popularity for a variety of applications in homeland security and nuclear medicine. In this paper we investigate its use for nuclear science spectroscopy applications in the context of in-beam gamma-ray spectroscopy with fast ion beams. In such experiments, the Doppler broadening of the gamma-ray line measured with a finite-size detector in the laboratory fundamentally limits the achievable energy resolution. For a typical experiment this effect is of the order of 3%. With the intrinsic energy resolution of LaBr 3:Ce better than 3% FWHM at 662 keV, and its favorable stopping power, it could be a nearly ideal scintillator for gamma-ray spectroscopy applications with fast beams. Results from in-beam gamma-ray spectroscopy measurements using two LaBr 3:Ce scintillators are presented and compared to results from segmented germanium detectors. Results from these measurements suggest that LaBr 3:Ce based scintillation arrays can provide a viable tool for many experiments. Additionally, we show that the excellent timing properties of LaBr 3:Ce can significantly reduce background events in the gamma-ray spectra.