Improvement of thickness and uniformity of isotopically enriched ~(12)C targets on backings by the HIVIPP method

摘要

We have made enriched ~(12)C targets to accurately measure the cross-section of the ~(12)C(α,y)~(16)O reaction, which is very important in nuclear astrophysics. Isotopically enriched ~(12)C targets for studying this small cross-section, especially for use with an intense pulsed α beam was desired to meet the following requirements: (1) use of impurity-free enriched ~(12)C, (2) stability for a long time measurement and (3) uniform thickness in the range 200-300 μg/cm~2. To meet these experimental requirements, isotopically enriched amorphous ~(12)C powder was converted into graphite powder in an electric furnace at a temperature of 3000 K and subsequently the graphite powder was deposited on a thick Au backing via the HIVIPP method. Targets thus prepared could be made thicker than 200μg/cm~2. They had a good uniformity and a very high stability against irradiation with high intensity ion beams.