Search

The “Rutgers Annihilation Spectrometer” (RAS) measures cross sections for antiproton annihilations as a function of the pp mass, final-state multiplicities, and degree of non-peripheralism, with a resolution of ±5 MeV and typical statistics of 10 6 events per mass bin 5 MeV wide. The non-annihilation events are suppressed by anticoinciding the events in which charged particles are emitted within the forward cones defined by the lab polar angles 2 1 2 °, 5°, 10° and 20° (4 “degrees of non-peripheralism”), eliminating single meson exchange mechanisms which are non-resonant and highly peripheral. Measurements are done at 7 incident a momenta simultaneously. Scintillation counters are the only detectors used. On-line data acquisition is accomplished by a hard-wired electronic processor (“MEGAHPOL”) capable of sorting data on 100 000 incident antiprotons per second.