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Energy straggling of protons in Be, C, Al, and Si

Journal Article · · Phys. Rev., B: Solid State; (United States)

Ion backscattering from solid targets of elements with prominent structure in their (p, p) scattering cross section has been used to measure the energy straggling of protons in Be, C, Al, and Si. Single-crystal targets were used in order to minimize porosity, channeling, and surface-roughness effects. In order to obtain straggling parameters from the experimental data, corrections for contributions, other than those mentioned above, to the broadening of the observed spectra were made. The energy dependence of the stopping power of the target for the protons makes a significant contribution to the broadening of the observed backscattering spectra, and must be properly accounted for if precise values of the straggling parameters are to be obtained. A procedure is described for accomplishing this. Using the experimental technique and analysis procedure described, proton straggling was evaluated in Be, C, Al, and Si in the energy range of 100--3000 keV. The results are summarized by defining f equivalent ..cap omega../..cap omega../sub B/, where ..cap omega../sub B/ is the straggling predicted by the Bohr theory. The results are: Be (E/sub res/ = 2.530 MeV), f = 1.0/sup +0.3//sub -1.0/; C (E/sub res/ = 0.47 MeV), f = 0.0/sup +1.5//sub -0.0/; C (E/sub res/ = 1.73 MeV), f = 0.9 +- 0.1; Al (E/sub res/ = 2.480 MeV), f = 1.25 +- 0.2; Al (E/sub res/ = 2.555 MeV), f = 1.25 +- 0.2; Si (E/sub res/ = 1.682 MeV), f = 1.15 +- 0.2; Si (E/sub res/ = 2.099 MeV), f = 1.4 +- 0.3. In addition to the straggling results, relative elastic scattering cross sections were determined for protons on Be (2.25--2.85 MeV, theta/sub lab/ = 170/sup 0/) and on Al (2.4--2.6 MeV, theta/sub lab/ = 170/sup 0/).

Research Organization:
Sandia Laboratories, Albuquerque, New Mexico 87185
OSTI ID:
6480496
Journal Information:
Phys. Rev., B: Solid State; (United States), Journal Name: Phys. Rev., B: Solid State; (United States) Vol. 18:9; ISSN PLRBA
Country of Publication:
United States
Language:
English