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FRAGT IS CHARGE BARYON WITH PATH < 4 CM.
FRAGT IS CHARGE BARYON WITH PATH < 4 CM.
FRAGT IS CHARGE BARYON WITH PATH < 4 CM.
We have measured the charge-changing cross sections of 10.6 GeV/nucleon Au197 nuclei interacting in targets of CH2 (polyethylene), C, Al, Cu, Sn, and Pb. Cross sections for H are calculated from those measured in C and CH2. The total charge-changing cross sections are higher than those measured at energies of ≤1 GeV/nucleon. The measured cross sections for the heavier targets are somewhat larger than those predicted by a model based on data taken at lower energies with lighter targets. Partial charge-changing cross sections for the production of fragments from the incident Au projectiles were measured for charge changes (ΔZ) from ΔZ=+1,80Hg, down to approximately ΔZ=-29,50Sn. In comparison to lower energy measurements, these partial cross sections are found to be smaller for small ΔZ and larger or the same for large ΔZ. The H partial cross sections are found to follow a power law in ΔZ similar to that for heavier targets, instead of the exponential form observed at lower energies. Factorization is found to hold for all partial cross sections with ΔZ greater than two. In the heavier targets, the cross sections for one and two proton removal have significant contributions from electromagnetic dissociation. The electromagnetic dissociation contribution to the total cross section is derived and found to be relatively small, but with a strong dependence on the charge of the target nuclei of the form ZT1.75±0.01.
TARGET NUCLEUS=CH2(POLYETHYLENE).
TARGET NUCLEUS=CH2(POLYETHYLENE).
Relativistic iron, lanthanum, holmium, and gold projectile nuclei with several different energies have been fragmented in targets of polyethylene, carbon, aluminum, copper, and lead. Our detectors cleanly resolve the individual charges of the heaviest of these fragments and provide some limited information on the masses. We have measured 1256 elemental partial cross sections for the production of fragments from interactions in these target materials. Values have been derived for another 417 cross sections in a hydrogen medium. These cross sections depend on the energy and mass of the projectile nuclei as well as on the nature of the target. Total charge-changing cross sections were also found, but only in a composite target, and have been shown to be weakly dependent on energy. The mean mass losses observed for fragments that have lost a few protons show that typically many neutrons are lost with each proton, producing fragment nuclei that must be highly proton rich, and consequently very unstable. The cross sections for charge pickup on heavy targets show a rapid increase with decreasing energy, particularly for the heaviest targets. The systematics of the dependencies of the partial cross sections will be discussed in a companion paper.
TARGET NUCLEUS=CH2.
No description provided.
No description provided.
Measurements of the partial charge-changing cross sections for the fragmentation of relativistic iron, lanthanum, holmium, and gold nuclei of several different energies incident on targets of polyethylene, carbon, aluminum, and copper have been reported in an accompanying paper. This paper describes the systematics of the variations of these cross sections with energy, projectile, target, and fragment. We have been able to generate a seven-parameter global fit to 795 measured cross sections for the heavy targets which fits the data with a standard deviation of 7%. We have also generated a similar global fit to 303 measured cross sections for a hydrogen target which fits the data with a standard deviation of 10%. These representations imply that the hypothesis of limiting fragmentation is only accurate to some 20–30 %. Weak factorization can apply, but fits that are marginally better, and more physically plausible, can be obtained without factorization. We have identified, and discussed, a number of caveats to the applicability of these fits outside, and inside, the range of energies and masses covered. Excessively large cross sections for the loss of a single proton from the projectile nuclei suggest electromagnetic dissociation. The cross sections for fragments that experience large charge changes appear to become independent of the size of the charge change. Very heavy projectiles have a significant probability of experiencing fission.
No description provided.
No description provided.
No description provided.
Electromagnetic fission cross sections of a 120 MeV/nucleon U238 beam incident on five targets, Be9, Al27, Cunat, Agnat, and Unat, have been extracted from measurements of projectile velocity fission fragments. The nuclear interaction contributions to the experimentally observed cross sections were determined by extrapolation from the Be target data using a geometrical scaling model and by an empirical decomposition of the fission charge distributions. The results are compared to model calculations in which electric quadrupole excitations have been included.
ELECTROMAGNETIC FISSION CROSS SECTIONS WERE DETERMINED FOR AL, CU, AG AND U TARGET, BE DATA IN TABLE CORRESPONDS TO NUCLEAR INTERACTION.
We used CR39 plastic nuclear track detectors (C12H18O7) in combination with automatic track measurement to determine total charge changing and partial cross sections for the production of fragments of chargeZ=6 andZ=7 in collisions of16O beam nuclei at energies of 60 GeV/nucleon and 200 GeV/nucleon in targets H, C, CR39, CH2, Al, Cu, Ag and Pb. Total charge changing cross sections due to the process of electromagnetic dissociation are calculated based on a theoretical model and found to be consistent with total and partial electromagnetic dissociation cross sections derived from this experiment. The energy dependence of pure nuclear fragmentation is investigated.
OBS = TOTAL CHARGE CHANGING CROSS SECTION.
No description provided.
No description provided.
We used CR39 plastic nuclear track detectors (C12H18O7) in combination with automatic track measurement techniques to determine total charge changing and partial cross sections for the production of fragments of chargeZ F =6 toZ F =15 in collisions of32S beam nuclei at energies of 0.7, 1.2 and 200 GeV/nucleon in targets H, C, CR39, CH2, Al, Cu, Ag and Pb. By application of factorization rules measured partial cross sections are separated into pure nuclear and electromagnetic components. Total and partial cross sections for electromagnetic dissociation are compared with theoretical models. The energy dependence of pure nuclear cross sections is investigated.
No description provided.
NUCLEUS=12C 18H 7O.
NUCLEUS=18C 38H 7O.
Inclusive cross sections for high energy interactions at 0.9, 2.3, 3.6, and 13.5 GeV/nucleon of O16 with C, CR-39 (C12H18O7), CH2, Al, Cu, Ag, and Pb targets were measured. The total charge-changing cross sections and partial charge-changing cross sections for the production of fragments with charge Z=6 and Z=7 are compared to previous experiments at 60 and 200 GeV/nucleon. The contributions of Coulomb dissociation to the total cross sections are calculated. Using factorization rules the partial electromagnetic cross sections are separated from the nuclear components. Energy dependence of both components are investigated and discussed.
No description provided.
We have investigated the fragmentation of 3.65 GeV/nucleon O16, Mg24, and S32 projectiles on C, Al, Cu, Ag, and Pb targets using solid state nuclear track detectors. Track counting was performed by an automatic measuring system. Total charge changing and the partial cross sections for the production of fragments with charges 9≤Z≤15 for S32 projectiles and of charge 6≤Z≤11 for Mg24 were determined. Comparison with theoretical models and other experimental data is made.
No description provided.
The fragmentation of 1.2 GeV per nucleon La139 nuclei has been studied. Total charge changing cross sections for H (CH2-C), C, and Pb target nuclei, and elemental production cross sections for C and CH2 targets for 1≤ΔZ≤30 have been measured. For heavy projectile fragments, the projected transverse momenta extracted are generally larger than predicted by models based on the internal momenta of nucleons in nuclei. Fits to the heavy fragment momentum distributions yield additional transverse momenta or ‘‘bounce-off’’ which range from ≃500 to 1000 MeV/c.
No description provided.
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