The Kaon Spectrometer At Sis

A double-focussing QD magnetic spectrometer has been developed and installed at the SIS heavy-ion facility at GSI in Darmstadt. The spectrometer's primary purpose is to study meson production in energetic nucleus-nucleus collisions in detail. Its compact design is matched to the requirements of kaon detection with short flight path (5-6.5 m), large solid angle (up to 35 msr), wide momentum acceptance (p(max)/p(min) congruent-to 2), maximum momentum 1.6 GeV/c (1.9 GeV/c at reduced solid angle) and reasonable momentum resolution (congruent-to 1% without and congruent-to 10(-3) with ray tracing). A focal-plane length of about 1.5 m allows the efficient use of the detectors necessary for particle identification and ray-tracing, involving wire chambers, time-of-flight scintillators and Cherenkov detectors. Collisions can be characterized by two multiple-module plastic-scintillator hodoscopes detecting reaction fragments in the forward hemisphere. While the primary purpose for the construction of the spectrometer is the measurement of kaons, it can serve as a general purpose magnetic spectrometer. Its large solid angle also allows the study of two-particle correlations.