Novel High Duty Cycle FFAG Betatron for Radiological Source Replacement
- RadiaBeam Technologies, LLC, Santa Monica, CA (United States)
Category 1 radiological sources, such as those used for radiation therapy and industrial irradiation processes, represent a significant radiological hazard for users and the public, and pose a threat of diversion for terrorist attacks. Replacing such sources with accelerators would constitute a major advance in public safety, and in the long run offer reduced handling and maintenance costs of the systems themselves. However, the current state-of-the-art, kW-class linacs used for irradiation are a stagnant technology, and their capital cost, footprint, and operational utility are limited by the need for high-power microwave sources (i.e. klystrons) to power the linac. In this project, RadiaBeam is developing a novel, high average power betatron accelerator that we term the Radiatron. Betatrons are circular induction accelerators that are commonly used for low dose rate applications such as industrial radiography, and they have already effectively replaced Co-60 and Cs-137 in most cargo inspection applications. However, the power achievable by a conventional betatron is insufficient to replace Category 1 sources, such as those used in medical device sterilization, materials processing, and food irradiation. The Radiatron is a rethinking of the betatron using modern materials and design techniques but still relying on inductive coupling as the accelerating mechanism (using no RF power). The Radiatron incorporates two key improvements on the conventional betatron: the deployment of a Fixed Field Alternating Gradient (FFAG) focusing scheme; and the use of modern, lower-loss magnetic materials. These improvements, combined with an efficient, fast-switching IGBT power system, enables the Radiatron to achieve two orders of magnitude faster acceleration than a conventional betatron, as well as much higher current output and quasi-CW operation mode. RadiaBeam has been pursuing the development of the Radiatron for over a decade We received initial funding to develop the design of the accelerator through the DOE SBIR program (funded by the Office of High Energy Physics), as well as additional investment from Ion Beam Applications SA (IBA). As a result of these efforts, a significant portion of non-recurrent engineering and system components development has already been carried out: the FFAG magnetic lattice design of this machine has been designed and demonstrated, and many other key subsystems, i.e. induction core and power supply, have already been built and tested. The remaining most challenging aspect of the Radiatron system that is currently preventing it from reaching market is the design of the extraction system. Unlike conventional betatrons that generally use internal X-ray conversion targets, the very high average power beams (> 10 kW) required to replace Category 1 sources in irradiators require extraction of the beam to an external scan horn. Thus, in Phase I, RadiaBeam efforts has been focused on the design and simulations of the resonant extraction system, including the transport line after extraction, scanning system, and optional X-ray converter. The implications of the new extraction system on the magnets design have also been revisited and taken into the overall design considerations. Additional efforts involved design and engineering of the new injection system, and UHV chamber with a ceramic break. The Phase I demonstrated feasibility of the Radiatron extraction system and addressed engineering and integration challenges for other relevant subcomponents. The strategic goal of this project is to develop and demonstrate the high-average power Radiatron prototype for Category 1 irradiator replacement and other industrial applications.
- Research Organization:
- RadiaBeam Technologies, LLC, Santa Monica, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- SC0017689
- OSTI ID:
- 1475183
- Type / Phase:
- SBIR (Phase I)
- Report Number(s):
- DOE-RBT-17689
- Country of Publication:
- United States
- Language:
- English
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