Charles Maguire

Alpha-particle emission in deeply inelastic reactions of 204-MeV /sup 16/O+/sup 93/Nb

Angular and energy correlations have been measured for ..cap alpha.. particles emitted in coincidence with projectilelike fragments from deeply inelastic collisions of 204-MeV /sup 16/O with /sup 93/Nb. Anisotropic emission of fast ..cap alpha.. particles is observed; however, the main results of this and similar experiments can be reproduced by model calculations which assume the ..cap alpha.. particles are evaporated from fully accelerated fragments and take the angular distribution of projectilelike fragments into account.

Event reconstruction in the PHENIX central arm spectrometers

The central arm spectrometers for the PHENIX experiment at the Relativistic Heavy Ion Collider have been designed for the optimization of particle identification in relativistic heavy ion collisions. The spectrometers present a challenging environment for event reconstruction due to a very high track multiplicity in a complicated, focusing, magnetic field. In order to meet this challenge, nine distinct detector types are integrated for charged particle tracking, momentum reconstruction. and particle identification. The techniques which have been developed for the task of event reconstruction are described.

Some properties of slow plastic scintillators

Abstract The decay times for two new plastic scintillators, the Nuclear Enterprises NE115 and the Bicron BC444, have been measured. They were determined to be 344 and 287 ns respectively. The light yield from an NE115 scintillator was also measured as a function of energy in the range 22.3–59.8 MeV. A good fit to these data points was obtained with the polynomial y = ax 1.06 , indicating minimal nonlinear effects for this scintillator in this energy range.

PHENIX on-line and off-line computing

Data handling in PHENIX is carried out by the On-Line Computing System (ONCS) and Off-Line Computing System (Off-Line). ONCS provides the overall control and monitoring of the front-end electronics, trigger and data acquisition system and detector ancillary systems. It configures and initializes the on-line system, monitors and controls the data flow, coordinates calibration processes, interlocks the data acquisition process with the slow control subsystems and performs a number of other functions. ONCS uses CORBA software to monitor and control the hardware. Off-Line provides all aspects of data handling not directly connected to the collection of data and monitoring, such as event simulation and reconstruction, data analysis and information management. The impact of the unprecedented data volumes on the design is presented, along with a detailed discussion of the tasks and methods of simulating, obtaining and monitoring the data.

Large-angle enhancements in the 16O(6Li, α)18F reaction at 48 MeV☆

Abstract The elastic scattering of 6 Li + 16 O at 48 MeV has been measured and fitted with an optical model calculation. Measurements have been made of the 16 O( 6 Li, α)F reaction at 48 MeV populating the 1 + g.s., 3 + 0.927 MeV and 5 + 1.122 MeV states in 18 F. The data exhibit cross sections at large angles comparable to those at forward angles, and have been compared with exact finite-range DWBA calculations. Exchange contributions were included for the 1 + g.s. and were unable to account for the large-angle data. Calculated statistical compound nucleus cross sections were approximately a factor of 100 below the data. The same conclusions are reached for previously published data at 34 MeV.

Calorimeter/absorber optimization for a RHIC dimuon experiment

The RD-10 R&D effort on calorimeter/absorber optimization for a RHIC experiment has an extended run in 1991 using the A2 test beam at the AGS. Measurements were made of the leakage of particles behind various hadron calorimeters. Behavior of the calorimeter/absorber as a muon-identifier was studied. First comparisons of results from test measurements to calculated results using the GHEISHA code were made.

Non-equilibrium particle emission in heavy-ion fusion-evaporation reactions

Abstract Non-equilibrium particle emission occurring in heavy-ion fusion-evaporation reactions is analyzed in terms of the moving source model. Different projectile-target combinations are seen to give different source characteristics depending upon the particle being detected. Non-equilibrium particle production in a heavy projectile reaction, 28Si + 40Ca, is practically non-existent even at a relatively high projectile velocity above the Coulomb barrier.