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HK: Hadronen und Kerne
HK 47: Instrumentation V, Detector Systems
HK 47.4: Gruppenbericht
Mittwoch, 18. März 1998, 15:00–15:30, A
The spectrometer ANKE at COSY — •K. Sistemich2, S. Barsov1, U. Bechstedt2, N. Bongers2, G. Borchert2, W. Borgs2, M. Büscher2, R. Eßer3, D. Gotta2, M. Hartmann2, H. Junghans2, F. Klehr4, H.R. Koch2, R. Maier2, H. Ohm2, D. Prasuhn2, R. Schleichert2, A. Schneider2, H. Schneider2, Chr. Schneider5, O.W.B. Schult2, H. Seyfarth2, and H.J. Stein2 — 1High Energy Physics Department, Petersburg Nuclear Physics Institute, Russia — 2Institut für Kernphysik, Forschungszentrum Jülich — 3Institut für Kernphysik, Universität zu Köln — 4Zentralabteilung Technologie, Forschungszentrum Jülich — 5Institut für Hadronen- und Kernphysik, Forschungszentrum Rossendorf
The spectrometer ANKE has been completed and installed inside COSY. It consists of three dipole magnets, which allow the separation of products from proton-induced reactions in internal targets of hydrogen, deuterium or heavier nuclei from the circulating beam and to determine their momenta and emission angles. This can be achieved for ejectiles in forward and backward direction, for |ϑ| < 15∘ with positive and negative charge. Targets of C and CH2 fibers, cluster and pellet targets as well as a storage cell for polarized H or D will be used. The fields of the dipole magnets have been mapped with the GSI field measuring device and the focussing properties have been determined with the floating wire technique. The vacuum chambers of the dipoles have exit windows of aluminized carbon fiber foils. They have walls of only 2 mm thickness, which reduces eddy currents during acceleration and permits to use almost the full heights of the magnet gaps for the measurements.
The detector system presently installed at the spectrometer is being tuned for the investigation of the K+ production in proton-nucleus interaction at projectile energies far below the N-N threshold and, thus, to study nuclear medium effects. The study of coincidences between kaons and light particles like deuterons will be possible in spite of an intense background of protons and pions. The identification of kaons is achieved with time of flight and energy loss measurements and with the use of a very efficient, but demanding first level trigger.
The first experiments with ANKE are scheduled for the first half of 1998. Pion production, e.g. from the reaction p p → d π+ will serve for commissioning and calibration as well as for studies concerning the N-N final state interaction. Then, double differential cross sections for K+-d coincidences will be measured in order to gain information about the reaction mechanism of the subthreshold K+ production.