The SAS Gamma-Ray Spectrometer For High Repetition Rate Laser Applications*

A new type of compact high-resolution high-sensitivity gamma-ray spectrometer for short-pulse

0.5-50 MeV gamma-rays has been developed by combining the principles of pixelated scintillators

and attenuation spectrometers. The first prototype of this scintillator attenuation

spectrometer (SAS) was tested successfully on Trident laser experiments and later improved

versions have been used extensively in Texas Petawatt laser experiments in Austin TX and 

OMEGA-EP laser experiments at LLE, Rochester NY. The SAS spectrometer is ideally suited

to diagnose gamma-rays from high-repetition-rate laser and HED experiments since it does not require the

use of image plates or radiographic films.  Instead the scintillation light profiles are recorded

by a CCD camera with millisecond time exposure.  Hence the SAS can be used in laser and HED

experiments of up to kHz repetition rates.  Here we provide a concise description of the design principles,

capabilities and preliminary results of the SAS from recent short-pulse laser experiments.