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Manuscript Title: Energy-loss straggling of heavy charged particles.
Authors: R.G. Clarkson, N. Jarmie
Program title: STRAGL
Catalogue identifier: ABON_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 2(1971)433
Programming language: Fortran.
Computer: CDC 6600.
Operating system: SCOPE 3.0.
RAM: 45K words
Word size: 60
Keywords: Nuclear physics, Energy straggling, Energy loss, Particle beams, Vavilov distribution, Distant collision Correction, Thin absorbers, Landau distribution, Atomic physics.
Classification: 17.2.

Nature of problem:
STRAGL calculates the energy-loss distribution (straggling) of a monoenergetic beam of charged particles, heavier than electrons, after it has passed through a thin absorber.

Solution method:
The energy-loss distribution is calculated using the formulas of Vavilov with the modification due to Shulek et al. which includes the effects of bound electrons. The calculation extends and corrects the older regions of the Landau distribution and the gaussian straggling distribution . The mean ionization potential of the absorber can either be supplied or will be calculated by the program. The output listing provides various parameters of interest used in the calculation, the mean energy loss, most probable energy loss, and the fwhm of the energy distribution. The distribution is then plotted on the listing directly, and a table is printed that lists the values of the distribution directly in probability per unit energy versus the energy loss.

The beam is assumed to be monoenergetic and heavier than electrons. There is no high energy limit. The low energy and the large thickness limits are determined by the restriction that the mean energy loss should not be more than 10 to 20% of the initial particle energy. For very thin absorbers (for example, a few keV energy loss), the calculation also fails: for details see the main text.