EFFECTS OF A HADRON IRRADIATION ON SCINTILLATING FIBERS

Trackers based on scintillating-fiber technology are being considered by the Solenoidal Detector Collaboration at SSC and the D0 collaborati on at Fermilab. An important issue is the effect of the radiation exis ting in the detector cores on fiber properties. Most studies of radiat ion damage in scintillators have irradiated small bulk samples rather than fibers, and have used X-rays, Co-60 gammas, or electron beams, of ten at accelerated rates. We have irradiated some 600 fibers in the Fe rmilab Tevatron C0 area, thereby obtaining a hadronic irradiation at r ealistic rates. Four-meter-long samples of ten Bicron polystyrene-base d fiber types, maintained in air, dry nitrogen, argon, and vacuum atmo spheres within stainless-steel tubes, were irradiated for seven weeks at various distances from the accelerator beam pipes. Maximum doses, m easured by thermoluminescence detectors, were about 80 Krad. Fiber pro perties, particularly light yield and attenuation length, have been me asured over a one-year period. A description of the work together with the results is presented. At the doses achieved, corresponding to a f ew years of actual fiber-tracking detector operation, little degradati on is observed. In addition, recovery after several days' exposure to air has been noted. Properties of unirradiated samples kept in darknes s show no changes after one year.