Non-radioisotopic gamma-ray calibration source for radiation detection instruments

C56-02a-273237 Radiation detection instruments are widely used in industrial radiography, radio spectroscopy, medicine, etc. Typical for these detectors routine calibration procedure uses up to a Category 2 radioisotope source as gamma-ray generator. However, the use of high-activity radioisotope sources (most often Cs-137 chloride) poses a radiological security risk since the sources have the potential to be lost or stolen and used in a radiological dispersal device or radiological exposure device. Accelerator based gamma-ray generators have the potential to be used in place of radioisotope sources, thus eliminating the security risk posed by radioisotopic sources. The 2021 National Academies of Sciences study on Radioactive Sources: Applications and Alternative Technologies highlighted a lack of progress in industry adopting alternative technologies for calibration systems due to a lack of viable, comparable, or cost-effective replacements. Proposed non-radioisotopic gamma-ray source designs must be reliable, robust to handle challenging environmental conditions, and should provide comparable dose rate, repeatability, and stability required for calibration. Euclid Beamlabs, LLC, in collaboration with Stanford Linear Accelerator Center and Argonne National Laboratory, submits this Phase I proposal to develop a compact accelerator-based (2.2 MeV electron beam energy) gamma-ray source for calibrations as a replacement for radioisotopic sources, which corresponds Cs-137 istope. We will design a portable light weight accelerator unit with integrated RF gun and gamma-ray convertor. Euclid has already developed an inexpensive 1 MeV accelerator for medical applications. This ultra-compact accelerator cavity is based on a brazeless design (Euclid Techlabs patent) with an internal field emission cathode (no additional high voltage electron gun) that is extremely robust, lightweight and portable. In phase I of the project, we will develop an RF design of the portable 2.2 MeV accelerating cavity with integrated RF gun and fabricate a mockup model for bench testing. We will optimize sensitivity to manufacturing errors and produce a final engineering design with the RF power supply system. The potential market for a non-radioisotopic gamma-ray source is significant, taking in account the current lack of a viable alternative to radioisotopic calibration systems constitutes a notable roadblock to the reduction of safety and security risks associated with Cs-137 worldwide. Finally, accelerator based gamma-ray sources can replace the need for radioisotope sources in calibration procedure of radiation detection instruments.