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Title: Energy-loss straggling caused by the inhomogeneity of target material

Abstract

Rutherford backscattering spectroscopy (RBS) accompanying with the sharp 4.808-MeV resonance of proton beams in carbon has been applied to examine the energy-loss straggling in detail, which causes the broadening of proton beam energy in the penetrating path. In the present measurements, RBS peak profiles of homogeneous and inhomogeneous carbon materials have been obtained with an incident energy of 5.5 MeV. Careful analyses of those profiles have revealed that the energy-loss straggling can be separated into two parts; one is collision straggling and the other is density straggling. The collision straggling is caused by the statistical fluctuation in collisions of proton with target atoms, which has been intensively studied since the theoretical work by Bohr [Philos. Mag. 30, 581 (1915)]. The density straggling is caused by the statistical fluctuation in local density of target material, which has been discussed in the present work. The random inhomogeneity as a measure of the fluctuation in the local density is introduced into the existing theory of the energy-loss straggling. Following the theoretical treatment, we have successfully deduced the random inhomogeneity of various carbon materials and the spatial spread of 4.808-MeV resonance protons in the materials. Some applications of the present method for the RBSmore » with the sharp resonance are also presented.« less

Authors:
 [1]
  1. Radioisotope Research Center, Kyoto University, Kyoto 606-8501 (Japan)
Publication Date:
OSTI Identifier:
20787872
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 99; Journal Issue: 3; Other Information: DOI: 10.1063/1.2168299; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CARBON; COLLISIONS; ENERGY LOSSES; MEV RANGE 01-10; PROTON BEAMS; RANDOMNESS; RESONANCE; RUTHERFORD BACKSCATTERING SPECTROSCOPY

Citation Formats

Tosaki, Mitsuo. Energy-loss straggling caused by the inhomogeneity of target material. United States: N. p., 2006. Web. doi:10.1063/1.2168299.
Tosaki, Mitsuo. Energy-loss straggling caused by the inhomogeneity of target material. United States. doi:10.1063/1.2168299.
Tosaki, Mitsuo. Wed . "Energy-loss straggling caused by the inhomogeneity of target material". United States. doi:10.1063/1.2168299.
@article{osti_20787872,
title = {Energy-loss straggling caused by the inhomogeneity of target material},
author = {Tosaki, Mitsuo},
abstractNote = {Rutherford backscattering spectroscopy (RBS) accompanying with the sharp 4.808-MeV resonance of proton beams in carbon has been applied to examine the energy-loss straggling in detail, which causes the broadening of proton beam energy in the penetrating path. In the present measurements, RBS peak profiles of homogeneous and inhomogeneous carbon materials have been obtained with an incident energy of 5.5 MeV. Careful analyses of those profiles have revealed that the energy-loss straggling can be separated into two parts; one is collision straggling and the other is density straggling. The collision straggling is caused by the statistical fluctuation in collisions of proton with target atoms, which has been intensively studied since the theoretical work by Bohr [Philos. Mag. 30, 581 (1915)]. The density straggling is caused by the statistical fluctuation in local density of target material, which has been discussed in the present work. The random inhomogeneity as a measure of the fluctuation in the local density is introduced into the existing theory of the energy-loss straggling. Following the theoretical treatment, we have successfully deduced the random inhomogeneity of various carbon materials and the spatial spread of 4.808-MeV resonance protons in the materials. Some applications of the present method for the RBS with the sharp resonance are also presented.},
doi = {10.1063/1.2168299},
journal = {Journal of Applied Physics},
number = 3,
volume = 99,
place = {United States},
year = {Wed Feb 01 00:00:00 EST 2006},
month = {Wed Feb 01 00:00:00 EST 2006}
}
  • The purpose of the present paper is to describe the effects of target electron collisions on proton energy loss straggling in plasmas at any degeneracy. Targets are considered fully ionized so electronic energy loss is only due to the free electrons. The analysis is focused on targets with electronic density around solid values n{sub e}{approx_equal}10{sup 23} cm{sup -3} and with temperature around T{approx_equal}10 eV; these targets are in the limit of weakly coupled electron gases. These types of plasma targets have not been studied extensively, though they are very important for inertial confinement fusion. The energy loss straggling is obtainedmore » from an exact quantum-mechanical evaluation, which takes into account the degeneracy of the target plasma, and later it is compared with common classical and degenerate approximations. Then electron collisions in the exact quantum-mechanical straggling calculation are considered. Now the energy loss straggling is enhanced for energies smaller than the energy before the maximum, then decreases around this maximum, and finally tends to the same values with respect to noncollisional calculation. Differences with the same results but not taking into account these collisions are as far as 17% in the cases analyzed. As an example, proton range distributions have been calculated to show the importance of an accurate energy straggling calculation.« less
  • The energy-loss straggling and energy width of states of slow ions interacting with a homogeneous electron gas are evaluated within a quadratic response theory and the random-phase approximation. These results are compared with corresponding results determined from a fully nonlinear scattering theory approach. The quadratic response theory is shown to be a good approximation for high electron densities and small ion charges. {copyright} {ital 1997} {ital The American Physical Society}