Ultrabright source produces MeV-class gamma rays

Researchers at Lawrence Livermore National Laboratory (Livermore, CA) have announced first light from a novel ultrabright gamma-ray source they call T-REX (Thomson-Radiated Extreme X-rays), intended for isotope-specific, high-resolution detection and imaging applications ranging from science experiments to detection of hidden nuclear materials.

Jun 1st, 2008

Researchers at Lawrence Livermore National Laboratory (Livermore, CA) have announced first light from a novel ultrabright gamma-ray source they call T-REX (Thomson-Radiated Extreme X-rays), intended for isotope-specific, high-resolution detection and imaging applications ranging from science experiments to detection of hidden nuclear materials. The light source is built around a dual-arm laser system.

One arm of the laser system produces fourth-harmonic 263 nm spatially and temporally flattop pulses that strike a photocathode; the resulting nanoCoulomb electron bunches are accelerated to 120 MeV via a five-stage linear accelerator while keeping their 2.5 mm-mrad emittance. The second arm of the laser system produces 1 J, 10 ps amplified pulses at 1064 nm, which are frequency-tripled to provide 100 mJ, 10 ps, 355 nm pulses; these are then focused on the high-energy electron beam. The result is about 106 0.776 MeV gamma-ray photons per pulse, as detected by a cesium iodide scintillator fiber-coupled to a multichannel plate and CCD sensor array. The peak brightness of T-REX tops 1017 photons/s/mm2/mrad2/0.1%bandwidth—a result that exceeds the gamma brightness of third-generation synchrotrons (such as the Advanced Photon Source in Argonne, IL) by six to nine orders of magnitude. Contact Christopher Barty at barty1@llnl.gov.

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