This SBIR Phase 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 present lack of suitable sources of intense (> 107 e+/sec) 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 proposed source is based on a new approach to the generation of intense slow positron beams: the production of the short-lived (+-emitter 13N via the light ion reaction 12C(d,n)13N. A compact, low energy deuteron accelerator with a specially-designed target and tungsten moderator will provide slow positron fluxes of greater than 107 e+/sec. A field assisted moderator which has the potential for providing >108 e+/sec will also be investigated. The proposed Phase I study will determine the maximum positron beam intensity which is feasible with this source. The initial market for the 3N-based intense slow positron source 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.
