J. L. Nagle

THE E864 LEAD-SCINTILLATING FIBER HADRONIC CALORIMETER

Abstract A large hadronic lead scintillating fiber calorimeter has been built and integrated into the AGS experiment E864 [C. Pruneau et al., E864 Collaboration, Proc. 6th Internal. Conf. on Calorimetry in High Energy Physics, 1996, Frascati, Italy; F. Rotondo et al., E864 Collaboration, Proc. Quark Matter96, Heidelberg, Germany, 20 May 1996] spectrometer to provide an independent measurement of the mass of particles produced in heavy ion collisions. The “spaghetti-type” calorimeter design and construction techniques are described in detail. Results from a prototype and the full implementation of the calorimeter are reported. The hadronic energy resolution of the calorimeter is found to be 6E/E = 0.035(± 0.005) + 0.344(± 0.008)/trE/GeV, in very good agreement with a FLUKA calculation. The hadronic time resolution is measured to be better than 400 ps. The combined calorimeter energy and time signals provide for a mass determination with good resolution. The mass resolution scales as δm/m = 0.026 + 0.347/√E(GeV) for velocities v/c

Scaling of deuteron production in ultrarelativistic nucleus-nucleus collisions

Abstract Deuteron production in S- and Pb-induced collisions at ultrarelativistic energies is studied in a transport model, treating the deuteron production by phase space coalescence. The production rate of deuterons as a function of rapidity, dN d dy , is approximately found to satisfy a simple scaling behavior in terms of the proton and the pion rapidity distributions, dN p dy and dN π dy , namely dN d dy ∼ ( dN p dy ) 2 /( dN π dy ) . The scaling is a consequence of the near equality of the freeze-out volumes the nucleons and mesons. Violation of the scaling is attributed to differences between these freeze-out volumes.

A high mass trigger for the E864 experiment at the AGS accelerator

Abstract The E864 experiment at the AGS is designed to carry out high sensitivity searches for a variety of possible new particles using relativistic heavy ion Au beams on Pb and Pt targets. In order to reach the desired sensitivities, a level-2 “late energy” trigger was built to select events in which a heavy particle is detected in a hadronic calorimeter with deposited energy and time-of-flight from the target exceeding preset values. The physics motivation for the trigger is discussed and and details of its hardware and software design are given. Performance results from recent E864 data taking runs are presented.

High rate multiplicity detector for relativistic heavy-ion collisions

Abstract We have constructed and operated a detector to measure the multiplicity of secondary particles produced in nucleus-nucleus collisions in the E878 experiment at the Brookhaven National Laboratory AGS facility. We describe the operation and performance of the detector in a high rate Au beam environment, and interpret the multiplicity data in terms of the impact parameters of the nucleus-nucleus collisions.