A WIDE-BAND PHOTON-BEAM AT THE FERMILAB TEVATRON TO STUDY HEAVY FLAVORS

For many years, the use of high energy photon beams has been recognize d as a good technique for the investigation of charmed particles [1]. The cross section is a relatively large fraction (approximately 1%) of the total hadronic cross section at high energies. The challenge was to develop a high energy and high intensity beam that produces enough charmed particles to obtain very high statistics so that one can answe r detailed questions about charm production and decays. The Fermilab w ide band photon beam is an attempt to meet that challenge. The beamlin e configuration and capabilities have evolved since the test run in 19 85 and the first physics run in 1987-88. For the 1990-91 data run, imp rovements were made to increase the photon yield and to improve the ph oton energy tagging resolution. Althought the main emphasis of this re port is on the original 1985-88 beam configuration, two fully operatio nal upgrades for the 1990-91 run, namely the incident electron beam mo mentum tagging spectrometer and the LD2 primary beam target, are descr ibed. The beam was also given the capability of transporting simultane ously e+ and e- beams. The performance of this ''double-band'' configu ration was studied briefly duing the 1990-91 running period and will b e described in a future publication. A description of the Fermilab E68 7 spectrometer utilizing this photon beam facility has recently been p ublished [2].