The SHI slow positron beam pulsing system using an induction cavity

We have developed a new slow positron beam pulsing system for the first time using an induction cavity. In the new system, slow positron beam bunching is performed by applying an induction cavity instead of a usual rf cavity. The induction cavity makes it possible to produce any kind of electric field change according to time. Hence the bunching efficiency of the induction cavity should be higher than that of the rf cavity which can produce only sine curves electric field change according to time. Variable-energy positron lifetime spectroscopy with the new slow positron beam pulsing system has been arranged. By using the new system, the positron lifetime in Cz–Si has been measured. A difference in positron lifetime between proton-irradiated and unirradiated Cz–Si has been observed. Hence proton induced defects in Cz–Si have been detected by using our new system. q1999 Elsevier Science B.V. All rights reserved