NOVEL NON-RADIOISOTOPIC PORTABLE CALIBRATION SYSTEM

C56-02a-272165Source-based (Cs-137 or Co-60) calibration systems produce gamma radiation fields of known energy and intensity for calibration of radiation monitoring equipment, dosimeters, and industrial/medical radiation technologies to ensure their accurate operation. These calibration systems are essential for the safe and correct use of such devices. However, the use of high- activity radioisotope sources poses a radiological security risk. End users of such calibration systems are willing to consider the use of non-radioisotopic source-based approaches if the design can be validated. There is currently no portable x-ray, or other non-radioisotopic system that provides the gamma-ray dose rate, repeatability, and stability needed for these calibrations. It is proposed that a custom designed x-ray tube combined with a moderate sized pulsed power driver can be used to replace the radioactive Cs-137 source in portable calibrators. The x-ray tube will approximate the energy spectrum of a cesium source. The pulsed power system will be carefully designed for extensive in-field use and include a unique built-in dosimeter to self-calibrate the system output for the desired dose rate, repeatability, and stability for a long operational life. In Phase I, it is proposed to investigate x-ray tube designs that will feature a large area electron emitter based on a multiple blade cylindrical cathode. This will reduce heat damage in the cathode and increase the lifetime of the tube. These types of designs have been explored with simulations in the past. In particular, the effort will evaluate designs to reduce the heating problems and lifetime issues of these previous designs, while maintaining reliability, stability, and power requirements for a portable system. A non-radioisotopic x-ray source of high dose rate, repeatability, and stability is of interest for both government and industry users who need to calibrate their instruments. The commercial potential of this solution, when developed to end products, includes portable and non-portable calibrators, industrial x-ray-based imaging systems, as well as some medical uses.