Charge-exchange effects in the energy-loss straggling of /sup 16/O ions in Al
The energy-loss straggling of /sup 16/O ions incident at energies from 5 to 50 MeV on Al foils of thickness 100 to 500 ..mu..g/cm/sup 2/ has been measured. Although the collisional straggling at energies above 25 MeV is expected to be appropriately described by the Bethe-Livingston theory of straggling, the data give values about a factor of 2 greater than this theory. The uniformity of the foils was studied and the limits to systematic errors that arise from this source were found to be small. The difference between the Bethe-Livingston theory and experiment is interpreted in terms of charge-exchange fluctuations. Monte-Carlo calculations have been made for /sup 16/O ions at 40 MeV (where only two charge states predominate), and the charge-exchange cross sections (8 x 10/sup -18/ cm/sup 2//atom for sigma/sub 7/+/sub arrow-right8/+ and sigma/sub 8/+/sub arrow-right7/+) required to produce a fit to the data are found to be similar in magnitude to those measured by Macdonald and Martin for 40-MeV /sup 16/O incident on N/sub 2/ and Ar gas targets.
- Research Organization:
- Nuclear Physics Division, A.E.R.E., Harwell, Didcot, United Kingdom
- OSTI ID:
- 7208058
- Journal Information:
- Phys. Rev., A; (United States), Journal Name: Phys. Rev., A; (United States) Vol. 17:3; ISSN PLRAA
- Country of Publication:
- United States
- Language:
- English
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