Member of the E687 Collaboration and the F.O.C.U.S. Collaboration
Maker of the Outer Electromagnetic Calorimeter
Check out the Outer em Calorimeter (a collection of images)
The Outer Electromagnetic of the E687/E831 experiment is a lead-scintillator sandwich calorimeter, covering the angular laboratory region from 25mrad to 155mrad, and characterised by 23 longitudinal samplings, 7 independent views, fine lateral segmentation (3.3 cm wide counters), 20% energy sampling fraction.
The E687 experiment studies the photoproduction and decay of charm particles using a high-energy (300-600GeV), high-intensity, wide-band photon beam. The spectrometer consists of a high-resolution silicon microstrip detector, a large aperture dipole magnet, a two-station multiwire proportional chambers, a second dipole and again a stack of three proportional chambers. Three Cerenkov counters along the spectrometer provide particle identification and a hadronic calorimeter permits to trigger on events with hadron in the final state, to reject electromagnetic interaction and to identify muons. Two lead-scintillator electromagnetic calorimeters, one at small and one at large angles, detect photons, reenforce and extend the electron-pion identification beyond the energy limit of the Cerenkov counters. This complement of detectors permits the observation of a wide variety of charmed baryon and meson productions and decays.
During the 1990-91 fixed target run at FERMILAB, some 80 thousand charm decays were completely reconstructed from about 500 millions hadronic triggers. Physics publications include precision measurements of lifetimes, semileptonic decays, Dalitz analyses, search for direct CP violation in the D meson system and study of QCD production mechanisms.
The experiment will take data during the next FERMILAB fixed-target run with an upgraded spectrometer, aiming to increase the charm statistics by a factor 10.