RADIOCHEMICAL STUDIES OF (P,BE-7) REACTIONS ON BIOLOGICALLY RELEVANT ELEMENTS IN THE PROTON ENERGY-RANGE OF 50 TO 350 MEV

Excitation functions for the (p,Be-7) reaction on natural C, N, O, F, Na, Al, Si, P, S, Cl, Ca and Fe were measured for proton energies from 50 up to 350 MeV using the stacked-foil technique. The data for P, S, Cl and Ca were determined for the first time, and some new informatio n was obtained for Fe in the energy range between 100 and 200 MeV. Whe reas in many cases the 7Be activity could be measured non-destructivel y via gamma-ray spectrometry, in targets containing P, S, Cl, Ca and F e it could only be determined after a radiochemical separation. The cr oss sections range between 220 mu b and 12 mb. The excitation function s show only a low energy dependence in the investigated energy range. A systematic survey of the data revealed that the (p,7Be) cross sectio n decreases with the increasing mass number of the target element. An estimate of the Be-7-activity formed in the tissue as a result of prot on radiation therapy is presented.