NSF Award
9712258
9712258 Shefer This Small Business Innovation Research Phase II project will develop the first turn-key, self-shielded accelerator-based intense positron beam source for use in research and industrial laboratories. Positron beams are powerful diagnostic probes for the nondestructive evaluation of metals, semiconductors, and polymers as well as for fundamental investigations of materials structure. A major impediment to the further development and use of positron-based diagnostics is the lack of suitable sources of intense slow positron beams. Presently-available radioisotope or electron LINAC sources are much too large and expensive for use in a laboratory or industrial environment. The positron source is based on the production of the short-lived (+-emitter 13N via the light ion reaction 12C(d,n)13N. The Phase I study showed that a low energy deuteron accelerator with a specially-designed carbon target and positron moderator will be able to provide slow positron fluxes equal to or greater than 107 e+/sec. The source, to be constructed in Phase II, will utilize a compact, high current accelerator. In addition to providing a relatively intense beam, the accelerator-based source will be easy to operate, and will contain little residual radioactivity when not in use. The initial market for the 13N-based intense slow positron source developed in this program will be university and industrial laboratories in the U.S. and abroad which are already using positron beams. The availability of the proposed source will facilitate the more widespread use of positron-based diagnostic techniques for semiconductors and metals. If these techniques come into routine use, the customer base for a diagnostic instrument based on this source may include the majority of semiconductor manufacturing facilities. ***
