A microbeam irradiator without an accelerator

The stand-alone microbeam, under development at RARAF, presents a novel approach to biological microbeam irradiation studies. Foregoing a conventional accelerator as a source of energetic ions, we propose to use a small, high-specific-activity, alpha emitter. Alpha particles emitted from this source are focused using a compound magnetic lens consisting of 24 permanent magnets arranged in two quadrupole triplets. Using a ‘‘home made’’ 6.5 mCi Polonium source, a 1 alpha particle/s, 10 lm diameter microbeam can be realized. As the alpha source energy is constant, once the microbeam has been set up, no further adjustments are necessary apart from a periodic replacement of the source. The use of permanent magnets eliminates the need for bulky power supplies and cooling systems required by other types of ion lenses and greatly simplifies operation. It also makes the microbeam simple and cheap enough to be realized in any large lab. 2005 Elsevier B.V. All rights reserved. PACS: 41.90.+e; 41.85.Ew; 06.60.Sx