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Manuscript Title: A Monte Carlo C-code for calculating transmission efficiency of recoil separators and viewing residue trajectories.
Authors: S. Nath
Program title: TERS
Catalogue identifier: AEBD_v1_0
Distribution format: tar.gz
Journal reference: Comput. Phys. Commun. 179(2008)492
Programming language: C.
Computer: The code has been developed and tested on a PC with Intel Pentium IV processor.
Operating system: Linux.
RAM: About 8 Mbytes
Keywords: Monte Carlo simulation, Recoil separator, Complete fusion reaction, Ion optics, Transmission efficiency.
PACS: 02.70.Uu, 29.30.h, 25.70.Jj, 41.85.p.
Classification: 17.7.

External routines: pgplot graphics subroutine library[1] should be installed in the system for generating residue trajectory plots.

Nature of problem:
Recoil separators are employed to select and identify nuclei of interest, produced in a nuclear reaction, rejecting unreacted beam and other undesired reaction products. It is important to know what fraction of the selected nuclei, leaving the target, reach the detection system. This information is crucial for determining absolute cross section of the studied reaction.

Solution method:
Interaction of projectiles with target nuclei is treated event by event, semimicroscopically. Position and angle (with respect to beam direction), energy and charge state of the reaction products are calculated by Monte Carlo method. Trajectory of each nuclei inside the separator is then calculated by ion optical transfer matrix method. Ratio of the number of trajectories completing their journey upto the detection system to the total number of trajectories is a direct measure of absolute transmission efficiency of the separator.

The present version of the code is applicable to complete fusion reactions only. The code can be applied to other types of reactions (e.g. few nucleon transfer) as well, by suitably modifying energy and angular distribution of reaction products. Also, ion optical specifications and acceptance are unique for each recoil separator. Transmission efficiency calculation has been done for a specific recoil separator, viz. the Heavy Ion Reaction Analyzer,[2,3] at IUAC. One has to make necessary changes in the code, while performing calculations for other recoil separators. Further, atomic number of the residual nucleus should not exceed 92, as the method used for calculating stopping power of ions [4] is valid for Z ≤ 92.

Running time:
From few seconds to several minutes depending on the reaction, number of events and separator layout.

[1] http://www.astro.caltech.edu/~tjp/pgplot/.
[2] A.K. Sinha, N. Madhavan, J.J. Das, P. Sugathan, D.O. Kataria, A.P. Patro, G.K. Mehta, Nucl. Instr. and Meth. A 339 (1994) 543.
[3] S. Nath, Nucl. Instr. and Meth. A 576 (2007) 403.
[4] J.F. Ziegler, J.P. Biersack, U. Littmark, The stopping and range of ions in solids, Vol. I (Pergamon Press, Oxford, 1984).