RadPhi TechNote
radphi-2004-301
March 10, 2004
The analysis of data taken with the Radphi experiment in summer 2000 has been hindered by the lack of a reliable method for associating an event in the detector with the energy of the photon in the beam that produced it. In principle the energy of the beam is tagged on an event-by-event basis by a coincidence between the detector and one of the channels of the tagging counters. This association is complicated by the fact that accidental coincidences with the tagger make event-by-event association ambiguous. Furthermore many of the interactions in the target that produce sufficient gamma energy to satisfy the trigger also include charged particles to which the calorimeters are largely insensitive. The result is that studies that look for association between the tagger channel and total energy in the detector have shown little if any correlation. This report shows how these problems can be overcome. An excellent agreement between the tagger channel and measured energy is demonstrated, in quantitative agreement with the resolution expected based upon prior studies of meson widths. The analysis procedures that incorporate the method are explained, and the total event yields obtained using photon tagging are provided.
This material is based upon work supported by the National Science Foundation under Grant No. 0303512.