Relativistic heavy ion fragmentation at HISS (Heavy Ion Spectrometer System)

Technical Report · Mon Oct 01 04:00:00 EDT 1990

DOI:https://doi.org/10.2172/6028607· OSTI ID:6028607

Tull, C E

An experiment was conducted at the Lawrence Berkeley Laboratory to measure projectile fragmentation of relativistic heavy ions. Charge identification was obtained by the use of a Cerenkov Hodoscope operating above the threshold for total internal reflection, while velocity measurement was performed by use of a second set of Cerenkov radiators operating at the threshold for total internal reflection. Charge and mass resolution for the system was {sigma}{sub Z} = 0.2 e and {sigma}{sub A} = 0.2 u. Measurements of the elemental and isotopic production cross sections for the fragmentation of {sup 40}Ar at 1.65{center dot}A GeV have been compared with an Abrasion-Ablation Model based on the evaporation computer code GEMINI. The model proves to be an accurate predictor of the cross sections for fragments between Chlorine and Boron. The measured cross section were reproduced using simple geometry with charge dispersions induced by zero-point vibrations of the giant dipole resonance for the prompt abrasion stage, and injecting an excitation energy spectrum based on a final state interaction with scaling factor E{sub fsi} = 38.8 MeV/c. Measurement of the longitudinal momentum distribution widths for projectile fragments are consistent with previous experiment and can be interpreted as reflecting the Fermi momentum distribution in the initial projectile nucleus. Measurement of the transverse momentum indicate an additional, unexplained dependence of the reduced momentum widths on fragment mass. This dependence has the same sign and similar slope to previously measured fragments of {sup 139}La, and to predictions based on phase-space constraints on the final state of the system.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6028607
• Report Number(s): LBL-29718; ON: DE91007741
• Country of Publication: United States
• Language: English

Related Subjects

651520* -- Nuclear Properties & Reactions
A=39-58
Experimental
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ARGON 40 TARGET
CALIBRATION
CHARGED-PARTICLE REACTIONS
CHERENKOV COUNTERS
CROSS SECTIONS
DATA
DRIFT CHAMBERS
EXPERIMENTAL DATA
FINAL-STATE INTERACTIONS
FISSION FRAGMENTS
GIANT RESONANCE
HEAVY ION REACTIONS
HODOSCOPES
INFORMATION
INTERACTIONS
LINEAR MOMENTUM
MASS RESOLUTION
MEASURING INSTRUMENTS
MULTIPLICITY
MULTIWIRE PROPORTIONAL CHAMBERS
NUCLEAR FRAGMENTATION
NUCLEAR FRAGMENTS
NUCLEAR REACTIONS
NUMERICAL DATA
PROPORTIONAL COUNTERS
RADIATION DETECTORS
RESOLUTION
RESONANCE
TARGETS