Multiplicity array for E866 Au+Au collisions at 11.6 A-GeV/c

This talk will cover the technical details of the new multiplicity array that we are constructing for experiment E866 at the AGS. In a second talk at this meeting, R. Seto will outline the physics motivation for this device. The detector will measure the multiplicity of fast particles in each collision of Au+Au at 11.6 A-GeV/c. The array will also provide an estimate of the reaction plane of the event using the predicted azimuthal anisotropy of the produced pions. The array will have approximately 500 threshold Cerenkov modules, each made of lucite that has been doped with wavelength shifter. This material affords a good match with the sensitivity of the photocathode and minimizes the position dependence of each module. We will discuss the testing of prototype modules and the details of the array`s design and construction.