Electrons from MAMI pass through a radiator and are bent by the tagger magnetic field into a Faraday cup in the wall of the A2 Hall. The Bremsstrahlung photons produced continue along the electron beam direction at the radiator. Some pass through a collimator in the tagger magnet return yoke, an experimental target in front of PiP and TOF and into a P2 ion chamber near the concrete door of the A2 hall. With each tagger channel we measure a \\ cross section = PIP/TOF counts coinc with tagger/(taggerscaler*etag*ePiP*eTOF)\\ into the PiP/TOF geometry, where tagger scaler is the number of counts in the scaler of a particular tagger channel, etag is the fraction of photons passing through the collimator (tagging efficiency), and ePiP and eTOF are detection efficiencies for PiP and TOF respectively. The tagged photon energy for each tagger channel can be worked out if we know the electron beam energy from MAMI and the tagger magnetic field.

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Dan Watts

Last modified: Fri Jan 18 15:45:25 GMT 2002