Improved Capillary Guided Laser Wakefield Accelerators based on Diamond Materials

Detection of smuggled nuclear materials concealed in cargo containers is an essential need for homeland security. A low cost and efficient method of scanning bulk cargo is to use a tunable energy gamma ray source. Laser plasma accelerators can currently produce (through Thomson backscattering) a gamma beam with the needed energy and positional scanning capability but are limited in intensity because of the low thermal conductivity of the sapphire capillary structure. We propose to develop a structure from artificial diamond that is compatible with the required intensity. Diamond has the highest thermal conductivity of any material, about 50 times larger than sapphire. Development of a diamond capillary structure will permit portable laser plasma sources of the requisite intensity to be constructed. We will complete thermal simulations of sapphire and diamond capillary devices. A diamond capillary device will be designed and fabricated. Initial testing of the structure will be performed at LBNL and the results evaluated. Commercial Applications and Benefits: Success of the proposed program will be a key step towards development of very compact, portable, and cost effective accelerators and gamma ray sources with applications in homeland security, basic research, and medicine.