Transverse momenta of helium fragments in gold fragmentation at 10.6 GeV/nucleon

The transverse momentum (pt) distributions of helium fragments from gold fragmentation on different nuclei of nuclear emulsion have been measured and a clear increase of average pt with target mass is seen. The pt distributions can be parameterized by a sum of three exponential functions of the form ∼ exp(- pt2/Bi). The differences in pt distributions in interactions on different targets can be explained by different contributions of the three exponential functions. These contributions depend on the projectile breakup in the collision, and for a given degree of the projectile breakup do not depend on the target mass. © Springer-Verlag 1997

Interactions of 10.6 GeV/n gold nuclei with light and heavy target nuclei in nuclear emulsion

We have investigated the particle production and fragmentation of nuclei participating in the interactions of 10.6 GeV/n gold nuclei in nuclear emulsions. A new criterion has been found to distinguish between the interactions of these gold nuclei with the light (H,C,N,O) and heavy (Ag, Br) target nuclei in the emulsion. This has allowed separate analyses of the multiplicity and pseudo-rapidity distributions of the singly charged particles emitted in Au-(H,C,N,O) and Au-(Ag,Br) interactions, as well as of the modes of breakup of the projectile and target nuclei. The pseudo-rapidity distributions show strong forward asymmetries, particularly for the interactions with the light nuclei. Heavy target nuclei produce a more severe breakup of the projectile gold nucleus than do the lighter targets. A negative correlation between the number of fragments emitted from the target nuclei and the degree of centrality of the collisions has been observed, which can be attributed to the total destruction of the relatively light target nuclei by these very heavy projectile nuclei. © 1994 Springer-Verlag

Interactions of 10.6 GeV/nucleon gold nuclei in nuclear emulsion

Stacks of nuclear emulsion were exposed at the Brookhaven AGS to a 10.6 GeV/n beam of gold nuclei in the BNL 868 experiment. A preliminary analysis of the main features of the interactions of these nuclei is reported here and compared with those observed previously at lower energies, E\u3c1 GeV/n. The multiplicity and pseudo-rapidity distributions of the singly charged particles emitted both in central and in minimum bias samples of interactions have been analyzed in order to look for any non random effects indicative of the nuclear state during the interactions. The fragmentation characteristics of the gold projectiles appear to be different at 10.6 GeV/n from those at ≦1 GeV/n incident energy. Fission of the gold projectiles, which was relatively frequent at low energy, is almost entirely suppressed. Some of alpha particles from the projectile are emitted with very large transverse momenta. In gold-emulsion interactions the residual target nuclei are significantly smaller than in oxygen and sulfur interactions in emulsion. © 1994 Springer-Verlag

Results from a large sample of MRPC-strip prototypes for the ALICE TOF detector

The MRPC (multi resistive plate chamber) strip is the basic element of the ALICE time-of-flight detector. A test of a large sample of MRPC-strip prototypes corresponding to 1.2% of the full detector was carried out during the autumn of 2002 at the CERN proton syncroton facility. This paper summarizes the main results obtained in terms of uniformity of response for all the tested channels

Operation of the Multigap Resistive Plate Chamber using a gas mixture free of flammable components

We have investigated the operation of the multigap resistive plate chamber (MRPC) for the ALICE-TOF system with a gas mixture free of flammable components. Two different gas mixtures, with and without iso-C4H10 have been used to measure the performance of the MRPC. The efficiency, time resolution, total charge, and the fast to total charge ratio have been found to be comparabl