A novel method for obtaining continuous stopping power curves

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Vol. 183; no. 3; pp. 203 - 211
• Main Authors: Trzaska, W.H., Alanko, T., Lyapin, V., Räisänen, J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2001
• Subjects: 40Ar; Stopping power; Time-of-flight; Stopping power; 34.50.Bw; 81.05.Bx; 40Ar; Time-of-flight
• ISSN: 0168-583X; 1872-9584
• DOI: 10.1016/S0168-583X(01)00728-5

A new method has been developed for obtaining continuous stopping power curves in transmission geometry. In the method both the incident energy of the particle and its energy after passing through the sample foil are extracted directly from the semiconductor detector. Full range of energies is measured simultaneously eliminating step-by-step measurements and providing continuous data. A time-of-flight (TOF) spectrometer provides unambiguous matching of relevant particle groups from the run with and without absorber. Suitable energy distribution of incident particles was achieved by choosing the right thickness and tilting angle of a scattering foil. The method is very fast and reliable. Sample results for stopping power values for 40Ar in Au, Ni, and polycarbonate are presented and compared with SRIM-2000 calculations. It is proposed to adopt a suitable standard for specific energy loss measurements to avoid possible discrepancies in energy calibration. For instance, Au or C would be good reference materials and all the new high precision data should be quoted not only in absolute values but also relative to the standard material that was measured with the same set-up. Our new method provides sufficient accuracy and speed to make such an approach feasible.