Discriminant analysis and secondary-beam charge recognition

Lukasik, J.; Adrich, P.; Aumann, T.; Bacri, C. O.; Barczyk, T.; Bassini, R.; Bianchin, S.; Boiano, C.; Botvina, A. S.; Boudard, A.; Brzychczyk, J.; Chbihi, A.; Cibor, J.; Czech, B.; Ducret, J. -E.; Emling, H.; Frankland, J.; Hellstrom, M.; Henzlova, D.; Imme, G.; Iori, I.; Johansson, H.; Kezzar, K.; Lafriakh, A.; Le Fevre, A.; Le Gentil, E.; Leifels, Y.; Luhning, J.; Lynch, W. G.; Lynen, U.; Majka, Z.; Mocko, M.; Muller, W. F. J.; Mykulyak, A.; De Napoli, M.; Orth, H.; Otte, A. N.; Palit, R.; Pawlowski, P.; Pullia, A.; Raciti, G.; Rapisarda, E.; Sann, H.; Schwarz, C.; Sfienti, C.; Simon, H.; Summerer, K.; Trautmann, W.; Tsang, M. B.; Verde, G.; Volant, C.; Wallace, M.; Weick, H.; Wiechula, J.; Wieloch, A.; Zwieglinski, B.

doi:10.1016/j.nima.2008.01.071

The discriminant-analysis method has been applied to optimize the exotic-beam charge recognition in a projectile fragmentation experiment. The experiment was carried out at the GSI using the fragment separator (FRS) to produce and select the relativistic secondary beams, and the ALADIN setup to measure their fragmentation products following collisions with Sn target nuclei. The beams of neutron poor isotopes around La-124 and Sn-107 were selected to study the isospin dependence of the limiting temperature of heavy nuclei by comparing with results for stable Sn-124 projectiles. A dedicated detector to measure the projectile charge upstream of the reaction target was not used, and alternative methods had to be developed. The presented method, based on the multivariate discriminant analysis, allowed to increase the efficacy of charge recognition up to about 90%, which was about 20% more than achieved with the simple scalar methods. ()C 2008 Elsevier B.V. All rights reserved.