Gillis Dyer | Searcharxiv

arXiv2019

A Scintillator Attenuation Spectrometer For Intense Gamma-Rays

A new type of compact high resolution high sensitivity gamma ray spectrometer for short pulse intense 250 keV to 50 MeV gamma rays has been developed by combining the principles of scintillators and attenuation spectrometers. The first prototype of this scintillator attenuation spectrometer or SAS was tested successfully in Trident laser experiments at LANL. Later versions have been used extensively in the Texas Petawatt laser experiments in Austin TX, and more recently in OMEGAEP laser experiments at LLE, Rochester, NY. The SAS is particularly useful for high repetition rate laser applications. Here we give a concise description of the design principles, capabilities and sample preliminary results of the SAS.

physics.ins-det↗

arXiv2014

Ultra-Intense Gamma-Rays Created Using the Texas Petawatt Laser

In a series of experiments at the Texas Petawatt Laser (TPW) in Austin, TX, we have used attenuation spectrometers, dosimeters, and a new Forward Compton Electron Spectrometer (FCES) to measure and characterize the angular distribution, fluence, and energy spectrum of the X-rays and gamma rays produced by the TPW striking multi-millimeter thick gold targets. Our results represent the first such measurements at laser intensities > 10 21 W*cm-2 and pulse durations < 150 fs. We obtain a maximum yield of X-ray and gamma ray energy with respect to laser energy of 4% and a mean yield of 2%. We futher obtain a Full Width Half Maximum (FWHM) of the gamma distribution of 37°. We were able to characterize the gamma-ray spectrum from 3 MeV to 90 MeV using a Forward Compton Electron Spectrometer, with an energy resolution of 0.5 MeV and mean kT of ~ 6 MeV.. We were able to characterize the spectrum from 1 to 7 MeV using a Filter Stack Spectrometer, measuring a mean gamma-ray temperature for the spectrum from 3 to 7 MeV of 2.1 MeV.

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