A detailed study of plastic scintillating strips with axial wavelength shifting fiber and VLPC readout

The upgrade of the Dφ detector at Fermilab is scheduled to run in 1999. One component of the upgrade is a cylindrically shaped preshower detector, placed on the outside of a solenoidal magnet that will surround the tracking volume. The technology for this detector will be plastic scintillating strips, with axial wavelength shifting (WLS) fiber and Visible Light Photon Counter (VLPC) readout. The VLPCs, with their quantum efficiency of ~70%, perform much better than traditional photomultipliers. We have performed extensive tests on different detector variations; investigating different scintillators, WLS fibers, and construction techniques. Prototype modules were placed in a cosmic ray test stand and over 120000 clean events per detector variant were collected. The large event sample and superior performance afforded by the VLPCs allow precise characterisation of the detector response. In this paper, we present results of our test programs, including uniformity of response, yields and interchannel crosstalk. We have achieved effective attenuation lengths exceeding 11 meters and yields of 4.5 photoelectrons per millimeter of scintillator traversed. An additional factor of 2 increase in yield seems achievable