Calibration of Phoswich Modules for Use in Experiments 859 and 866 at the Brookhaven AGS

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Gamma-ray peak shapes from cadmium zinc telluride detectors

We report the results of a study of the peak shapes in the gamma spectra measured using several 5 x 5 x 5 mm{sup 3} cadmium zinc telluride (CZT) detectors. A simple parameterization involving a Gaussian and an exponential low energy tail describes the peak shapes sell. We present the variation of the parameters with gamma energy. This type of information is very useful in the analysis of complex gamma spectra consisting of many peaks

Exclusive light particle measurements for the system 19^{19}F + 12^{12}C at 96 MeV

Decay sequence of hot {31}^P nucleus has been investigated through exclusive light charged particle measurements in coincidence with individual evaporation residues using the reaction {19}^F (96 MeV) + {12}^C. Information on the sequential decay chain have been extracted by confronting the data with the predictions of the statistical model. It is observed from the present analysis that such exclusive light charged particle data may be used as a powerful tool to probe the decay sequence of the hot light compound systems.Comment: 13 pages, 8 figures, Physical Review C (in press

Strangeness Enhancement in p+Ap+A and S+AS+A Interactions at SPS Energies

The systematics of strangeness enhancement is calculated using the HIJING and VENUS models and compared to recent data on $\,pp\,$, $\,pA\,$ and $\,AA\,$ collisions at CERN/SPS energies ($200A\,\, GeV\,$). The HIJING model is used to perform a {\em linear} extrapolation from $pp$ to $AA$. VENUS is used to estimate the effects of final state cascading and possible non-conventional production mechanisms. This comparison shows that the large enhancement of strangeness observed in $S+Au$ collisions, interpreted previously as possible evidence for quark-gluon plasma formation, has its origins in non-equilibrium dynamics of few nucleon systems. % Strangeness enhancement %is therefore traced back to the change in the production dynamics %from $pp$ to minimum bias $pS$ and central $SS$ collisions. A factor of two enhancement of $\Lambda^{0}$ at mid-rapidity is indicated by recent $pS$ data, where on the average {\em one} projectile nucleon interacts with only {\em two} target nucleons. There appears to be another factor of two enhancement in the light ion reaction $SS$ relative to $pS$, when on the average only two projectile nucleons interact with two target ones.Comment: 29 pages, 8 figures in uuencoded postscript fil

Au+Au Reactions at the AGS: Experiments E866 and E917

Particle production and correlation functions from Au+Au reactions have been measured as a function of both beam energy (2-10.7AGeV) and impact parameter. These results are used to probe the dynamics of heavy-ion reactions, confront hadronic models over a wide range of conditions and to search for the onset of new phenomena.Comment: 12 pages, 14 figures, Talk presented at Quark Matter '9

Monte Carlo study of a high-sensitivity gamma-ray detection system

The authors use Monte Carlo calculations to study a new design for a high-sensitivity gamma-ray detection system. The system uses an array of high-purity germanium detectors operating with an event-mode data acquisition system. The calculations show that the proposed design could produce a factor of 10 increase in the sensitivity of these measurements compared to currently employed systems

Gamma ray line shapes from cadmium zinc telluride detectors: An interim report

CdZn telluride (CZT) gamma ray detectors, operating at ambient temperatures, are potentially useful for safeguards applications such as assay and isotopic analysis of nuclear materials in the field. To analyze the complex gamma spectra, the gamma line shapes, including the amplitude and shape of the tail, must be understood. We have studied the line shapes in spectra taken with a CZT 5x5x5 mm detector. Standard gamma sources covering the energy range 59 to 661 keV were used. After background subtraction, the peaks were fit to a sum of a Gaussian and an exponential tail confined to the lower energy side of the Gaussian. The energy dependence of the various parameters that describe the gamma lines are graphed. The variance of the Gaussian increases linearly with gamma energy. Slope of the exponential tail varies strongly with energy at low gamma energy and then becomes nearly constant. Tail amplitude is larger for CZT than for a Ge detector. Tail cutoff parameter is not a very sensitive parameter for describing the line shape. Using these line shape parameters, gamma spectra at 90-100 keV from small uranium samples with 2 to 75% 235U were analyzed: the x rays from 235U decay and the gammas from 238U-234Th were used to determine the 235/238 ratio. This ratio could be determined to a few percent accuracy if the 235U enrichment did not exceed about 50%

Target rapidity baryon distributions in {sup 28}Si + {sup 197}Au and {sup 197}Au + {sup 197}Au collisions at 14.6 and 11.7 A{center_dot}GeV/c

Proton and deuteron kinetic energy spectra have been measured at target rapidities for both minimum bias and central collisions of 14.6 A{center_dot}GeV/c {sup 28}Si and 11.7 A{center_dot}GeV/c {sup 197}Au beams with a {sup 197}Au target. The spectra were measured from a low energy threshold of approximately E{sub kin}=35 MeV to well over 200 MeV for laboratory angles of 50{degree} to 130{degree} ({vert_bar}{eta}{vert_bar} {le}0.76). The acceptance-corrected spectra have been fit over a limited range of kinetic energies using a Boltzmann distribution. The integrated yields and the inverse slope parameters are presented as a function of centrality for the {sup 28}Si + {sup 197}Au reaction and as a function of trigger for the {sup 197}Au + {sup 197}Au reaction. These quantities are also compared with the proton spectra generated using both the ARC and RQMD codes