Lithium fluoride (LiF) crystal for parametric X-ray (PXR) production

Parametric X-ray (PXR) production is reported using lithium fluoride (LiF) as a target crystal interacting with 56 MeV electrons from the Rensselaer Polytechnic Institute (RPI) linear accelerator. Target crystals of Si, Ge, W, Cu, HOPG (graphite), and LiF have been studied. LiF shows the most promise for achieving an intense, quasi-monochromatic X-ray source for energies less than 40 keV. At these energies, photon absorption demands a low Z PXR target crystal for optimum yield. While HOPG graphite also meets this criterion, LiF can produce PXR with an energy linewidth narrower than achievable with graphite with 0.4° mosaic spread and at larger Bragg angles than necessary to produce equivalent PXR energies with graphite. PXR from 1.5 mm-thick LiF crystals is produced with electron beam currents up to 1.3 μA. Bragg and Laue geometries for PXR production with large LiF crystals (5 cm diameter) are compared for their Bremsstrahlung production. Reflection of PXR using a second crystal was experimentally performed.