A novel method for obtaining continuous stopping power curves

A new method has been developed for obtaining continuous stopping power cur ves in transmission geometry. In the method both the incident energy of the particle and its energy after passing through the sample foil are extracte d directly from the semiconductor detector. Full range of energies is measu red simultaneously eliminating step-by-step measurements and providing cont inuous data. A time-of-flight (TOF) spectrometer provides unambiguous match ing of relevant particle groups from the run with and without absorber. Sui table energy distribution of incident particles was achieved by choosing th e right thickness and tilting angle of a scattering foil. The method is ver y fast and reliable. Sample results for stopping power values for Ar-40 in Au, Ni, and polycarbonate are presented and compared with SRIM-2000 calcula tions. It is proposed to adopt a suitable standard for specific energy loss measurements to avoid possible discrepancies in energy calibration, For in stance, Au or C would be good reference materials and all the new high prec ision data should be quoted not only in absolute values but also relative t o the standard material that was measured with the same set-up. Our new met hod provides sufficient accuracy and speed to make such an approach feasibl e. (C) 2001 Elsevier Science B.V. All rights reserved.