APPLICATIONS OF TECHNOLOGY:
- Interrogation systems for special nuclear materials (SNM)
- Nuclear experiments and detector calibration
- More efficient and safer than conventional high energy photon sources
- Inexpensive construction
- Can be used for isotope analysis of fissile material
Scientists at Berkeley Lab have invented a coaxial accelerator that efficiently produces gamma rays at discrete high energy levels (6 or 12 MeV) using a low energy ion beam accelerator. The monoenergetic gamma rays minimize the absorbed radiation dose and the need for heavy shielding, and they produce less photon background than the existing alternatives, such as bremstrahlung photon sources.
Several features of the device contribute to its efficiency and unprecedented ability to generate high ion currents, which translate directly to high photon fluxes. These features include an efficient DC high voltage stage, an innovative coaxial arrangement of accelerator electrodes, differential gas pumping, and secondary electron suppression via target biasing. The device is able to deliver a pulsed beam with pulse widths of a few hundred nanoseconds and repetition rates in the tens of kilohertz range. In addition, it can simultaneously use two or more target materials to generate photons with discrete energies. This feature can be used to provide supplementary information about detected SNMs, such as their isotopic enrichment ratios.
An inexpensive axial version of this invention has been constructed mostly from off-the-shelf parts for less than a quarter of the cost of other high energy electron accelerators. Both the axial and coaxial high energy gamma generators address the challenges facing existing accelerator-based photon sources such as reducing cost and background, increasing power efficiency, and minimizing the requirement for heavy and cumbersome shielding.
DEVELOPMENT STAGE: Proven principle.
STATUS: Published US Patent Application 12/512,424 available at www.uspto.gov. Available for licensing or collaborative research.
FOR MORE INFORMATION:
Reijonen J., N. Andresen, F. Gicquel, R. Gough, M. King, T. Kalvas, K.-N. Leung, T.-P. Lou, H. Vainionpaa, A. Antolak, D. Morse, B. Doyle, G. Miller, M. Piestrup. “Development of advanced neutron/gamma generators for imaging and active interrogation applications,” Proc SPIE. 6540P-1–P-12 (2007).
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REFERENCE NUMBER: IB-2341