Dr. Andrey Mishin will be the featured speaker at this month's Nuclear & Plasma Sciences Society meeting. His presentation, Portable Linear Accelerators for Industrial and Medical Applications, discusses portable microwave linear accelerators for electron beam curing of composites, non-destructive testing, radiation therapy and other commercial applications.

Comparatively light-weight electron beam sources allow curing of graphite composites with thickness up to 3 cm when irradiated from one side and 7 cm when irradiated from two sides in time periods of several minutes to several hours, depending on electron beam power generated.

The same systems with lower electron beam power are used for non-destructive evaluation (NDE) and testing of thick and dense objects using radiation flux produced by an electron beam stopped in a heavy metal target.

It is possible to mount any of these portable linac heads on a robotic or C-arm for radiation processing purposes. Some of these systems can be transported in a truck.

The speaker will discuss a variety of linacs for a broad range of applications including systems for medical applications, synchrotron light sources, microwave pulse compression (SLED-cavities) and sterilization. The accelerator sections are also applicable to free electron lasers, etc. Two medical systems, the Mobetron and Cyberknife, have been developed at Schonberg Research Corporation (SRC) together with the spin-off companies Intraop and Accuray, respectively.

Along with standard systems, a number of new products are being developed as the range of parameters is broadened. New products will make it possible to build comparatively inexpensive electron beam sources with average beam power from 10 to 100 kW and energy from 1 to 10 MeV. This development is focused on portable systems with beam power in the 1 to 35 kW range which can be mounted on a crane or a robot.

In order to reduce mass and weight of powerful electron beam systems operating at 10 MeV electron energy and delivering beam powers exceeding 10 kW, one needs to pursue a technical strategy of reducing applied high voltages at the key system elements. This, in turn, requires several original concepts to be applied to the accelerator structure design:

1. Electron guns operating below 20 kV
2. Linac designs with low-voltage injection
3. Acceleration without an external focusing system, whenever possible
4. Maximum simplicity and serviceability in the system design
5. New designs using a maximum of standard elements
6. Use of advanced microwave power sources

As an example of advanced microwave sources, a magnetron with high peak and average power (10 MW and 30 kW, respectively) operating at a frequency of 1818 MHz is being upgraded to 50 kW of average output power. Experimental characteristics will be presented. Also, unique, multiple-beam S-band klystrons are being used in portable systems with low cathode voltage, permitting cathode operation in air.

These magnetrons and klystrons can be used on particle accelerators for various scientific applications as well as for beam processing needs, such as sterilization, electron beam curing, etc. These and other applications will be described.

Andrey V. Mishin graduated from the Moscow Engineering Physics Institute in 1985, where he earned his Ph.D. degree in 1992. Dr. Mishin has 14 years experience in particle accelerator and microwave systems design, development, manufacturing and program management. He joined Schonberg Research Corporation (SRC), Santa Clara in 1993 where he is presently Vice President and Technical Director. In 1994, he co-founded Traspace International Corporation, representing several companies, including SRC and Toriy, a manufacturer of advanced microwave equipment.
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SLAC # Take Sand Hill Road east from I-280 or west from the Stanford University campus. Continue to the main SLAC entrance at 2575 Sand Hill Rd. After the guard shack, turn right and proceed past Building 41, the A&E building. Park in Lot F or G by the Fire Station (Building 82.) Enter Building 44, the Test Lab Bldg, at the north entrance which faces the A&E building. The Klystron Conference Room (Room 131) will be on your left.