Effects of hadron irradiation on scintillating fibers

Trackers based on scintillating-fiber technology are being considered by the Solenoidal Detector Collaboration at SSC and the DO collaboration at Fermilab. Some 600 fibers in the Fermilab Tevatron CO area were irradiated, thereby obtaining a hadronic irradiation at realistic rates. Four-meter-long samples of ten Bicron polystyrene-based fibre types, maintained in air, dry nitrogen, argon, and vacuum atmospheres within stainless-steel tubes, were irradiated for seven weeks at various distances from the accelerator beam pipes. Maximum doses, measured by thermoluminescence detectors, were about 80 krad. Fiber properties, particularly light yield and attenuation length, were measured over a one-year period. A description of the work together with the results is presented. At the doses achieved, corresponding to a few years of actual fiber-tracking detector operation, little degradation was observed. Recovery after several days' exposure to air was noted. Properties of unirradiated samples kept in darkness show no changes after one year. >