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Manuscript Title: Identification of nuclear reactions registered in ionographic detectors.
Authors: M. Ortega, A. Vidal-Quadras, M. Tomas, F. Fernandez, V. Gandia, C. Jacquot
Program title: JOTOV
Catalogue identifier: ABKF_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 11(1976)287
Programming language: Fortran.
Computer: UNIVAC 1108.
Operating system: EXEC 8.
RAM: 24K words
Word size: 36
Peripherals: disc.
Keywords: Nuclear physics, Reaction, Ionographic detector, General experiment, Minimization, Chi-square probability, Intermediate energy, Range-energy relation, Analysis.
Classification: 17.4.

Nature of problem:
A nuclear reaction appears in a ionographic detector as an interaction star whose geometry can be accurately measured. Identity and energy of incoming beam are known but identity of target and emergent prongs are not. Once a target has been assumed and a charge and mass number hypothesis (Z,A) has been made for each prong, the complete kinematics of the reaction can be established. All possible hypotheses are examined under the requirements of conservation of momentum and total energy.

Solution method:
The chi-square function is minimized by the method of Lagrange multipliers, the conservation of momentum and energy giving the four constraints. This leads to a system of non-linear equations which are solved by an iterative procedure. Convergence of parameters and conservation values is tested during the resolution.

Running time:
Typical CPU times for identification of one event in nuclear emulsion are:
                                                                    
 -------------------------------------------------------------------     
 Beam           Possible targets        Number of Prongs     Time (s)    
 --------------------------------------------------------------------    
 Alpha          C,N,O                   4                     20         
 Alpha          C,N,O                   5                     45         
 ALpha          C,N,O                   6                    150         
 Proton         C,N,O                   4                      4         
 Proton         C,N,O                   5                     18         
 Proton         C,N,O                   6                     80         
 Proton         C,N,O                   7                    145         
 -------------------------------------------------------------------- 
These times represent an average over a great number of events.