There is an ongoing effort to replace high activity radioactive sources that could pose a risk for use as terrorist weapons with non-radioisotope based technologies. Currently radioactive sources serve a number of critical needs including the treatment and diagnosis of disease, inspection and certification of critical mechanical structures, the sterilization of food and medical products, and in petroleum exploration. A specific critical need is an alternative 137Cs blood irradiators used at blood banks to inactivate T-lymphocytes in blood products to prevent Transfusion Associated Graft-Versus-Host Disease (TA-GVHD). In this program National Nanomaterials proposes to develop a compact high power density x-ray source for irradiating blood samples as a replacement for the gamma rays produced by 137Cs that are presently used. This new X-ray based irradiator will be capable of delivering a minimum of 1500 centigrays (cGy) or 15 grays to all points within the irradiator without exceeding 3 x that dose anywhere within the irradiated volume. To accomplish this, National Nanomaterials will develop an irradiator using a compact, high current density, uniform field emission electron sources to generate the x-rays. In Phase I of the program, National Nanomaterials will build and optimize a high current density, uniform emission 1 & quot;x1 & quot; field emission x-ray source. These electrons will be accelerated directly into a tungsten anode to generate the x-rays. These sources will serve as the building blocks of the irradiator system to be constructed and tested in Phase II. Commercial Applications and Other
Benefits: The development of X-ray system to replace current 137Cs Blood irradiations will have significant sales once the product is developed. National security dictates that blood irradiation system must move from Cs to X-ray sources so all of the Cs based systems will need to be replaced. Once the graphene is shown to be an excellent electron source for x-ray tubes, National Nanomaterials will examine other markets for field emission sources which will provide additional revenue. These include production of compact traveling wave tubes for satellite communication, cathodes for other x-ray systems, and rad hard electrical devices.
