PARAMETRIC RADIATION AS AN INTENSE MONOCHROMATIC X-RAY SOURCE

PARAMETRIC-X-RADIATION (PXR) IS BEING INVESTIGATED IN PHASE I OF THIS PROJECT AS AN INTENSE, MONOCHROMATIC X-RAY SOURCE. THIS RADIATION IS HIGHLY COLLIMATED, HAS A BANDWIDTH OF 0.1% FULL WIDTH AT HALF MIXIMUM, AND AN INTENSITY EQUAL TO THAT OF SYNCHROTON RADIATION ON A PER ELECTRON BASIS. PXR IS PRODUCED BY A HIGH ENERGY (>1MEV) ELECTRON PASSING THROUGH A CRYSTALLINE STRUCTURE; AS THE ELECTRON PASSES THROUGH THE PLANES OF A CRYSTAL, IT EXCITES THE CRYSTALLINE ELECTRONS ALONG THE PLANES. IF THE PATH OF THE INCIDENT ELECTRON IS PROPERLY ALIGNED WITH RESPECT TO THE PLANES OF THE CRYSTAL, THE RADIATION GIVEN OFF BY THE EXCITATIONS AT THE SUCCESSIVE PLANES WILL ADD COHERENTLY, PRODUCING DIRECTIONAL MONOCHROMATIC RADIATION IN A PROCESS SIMILAR TO THE BRAGG DIFFRACTION OF X-RAYS. INDEED, THE ENERGY AND DIRECTION OF PXR IS GIVEN BY THE BRAGG RELATION FOR THE GIVEN GEOMETRY. BECAUSE PARAMETRIC RADIATION IS EMITTED AT AN ANGLE TO THE ELECTRON BEAM, IT IS EASILY SEPARATED FROM THE ELECTRON BEAM AND BREMSSTRAHLUNG. THIS FACT, ALONG WITH THE NARROW BANDWIDTH, COLLIMATION, AND INTENSITY OF PARAMETRIC RADIATION MAKE PXR A PROMISING X-RAYSOURCE FOR NONINVASIVE DIGITAL SUBTRACTION ANGIOGRAPHY AND OTHER APPLICATIONS THAT REQUIRE INTENSE, TUNABLE RADIATION PEAKS. THIS PROJECT INCLUDES (1) DETERMING THE MAXIMUM PARAMETRIC X-RAY INTENSITY THAT CAN BE ACHIEVED FROM A CRYSTAL BY ANALYZING THE EFFECT OF THE CRYSTAL COMPOSITION ON THE MAXIMUM SUSTAINABLE ELECTRON CURRENT AND THE RESULTING MAXIMUM X-RAY PRODUCTION, (2) STUDYING THE USE OF LAYERED SYNTHETIC MEDIA TO PRODUCE GREATER INTENSITY BY INCREASING THE BANDWIDTH OF THE RADIATION, AND (3) STUDYING THE USE OF MULTIPLE CRYSTALS TO INCREASE THE RADIATION INTENSITY. THE RESULTS OF THIS RESEARCH SHOULD ESTABLISH THE VIABILITY OF PXR AS AN INTENSE, COLLIMATED, MONOCHROMATIC X-RAY SOURCE.