Liquid Deuterium Neutron Attenuator for Broad-Band Photon Beam Facility

The photo-production facility at Fermilab utilizes a two section liquid deuterium attenuator, 103 feet in length, to reduce the neutron flux and produce a pure high energy photon beam. The facility is located in the Proton East experimental hall. The facility also includes nine 10 foot long sweeping magnets. A unique refrigeration system supplies mechanically refrigerated helium gas trace cooling to condense deuterium directly in a flask. The control system permits remote operation of the cryogenic system and also acts as an interface to the Proton Area operations computer. The computer can be used to monitor the operating parameters and for partial control of the system. The facility is presently in use as part of the Proton Area experimental program.