Design and performance characteristics of the E769 beamline transition radiation detector

A transition radiation detector (TRD) was designed and built for E769, a Fermilab fixed target experiment for use in separating pions from protons or kaons in a 250-GeV/c positive beam at the Tagged Photon Laboratory. Requirements placed on the detector were that it operate in a high rate (≈2 MHz) environment and that it be relatively easy to build since it had to be ready approximately one year from the date of its inception. The short time available precluded exposing prototypes to a test beam, making it necessary to rely on source testing and Monte Carlo programs to predict the detector performance. When operated in the beam, the detector performance was in good agreement with these predictions. For a pion detection efficiency of 87%, the contamination by protons of a sample of TRD tagged pions was 2%