skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: ANTIPROTON-NUCLEON CROSS SECTIONS FROM 0.5 TO 1.0 BEV (thesis)

Technical Report ·
OSTI ID:4137943

Antiproton-production and nucleon-interaction cross sections were determined for antiprotons in the energy range 0.5 to 1.0 bev. The production of antiprotons in hydrogen by 6.0-bev incident protons was investigated by observing the number of antiprotons produced in polyethylene and carbon targets within the Bevatron. The antiprotons were identified by a system of scintillation and velocity-selecting Cherenkov counters. The results indicated that antiproton production in hydrogen is negligible compared with production in carbon. The excitation function and momentum distribution were recorded for an proton production in carbon and compared with statistical model expectations. After the antiprotons made their exit from the Bevatron, they were directed by a system of bending and focusing magnets to a liquid hydrogen target. An array of plastic scintillation counters, which nearly surrounded the hydrogen target, was used to determine the p-p total, elastic, inelastic, and charge-exchange cross sections at five energies in the above energy range. It was found that the total cross sections are everywhere much larger than the n-n cross sections for comparable energies. Near 500 Mev the total p-p cross section is about 120 mb; it slowly decreases to 100 mb near 1 bev. The inelastic cross section, which is principally due to the annihilation process, represents nearly 2/3 of the total cross section. The elastic scattering distribution is highly peaked in the forward direction and can be fitted by optical-model analysis. The total and partial cross sections were also determined for the collisions of antiprotons with deuterons. The p-d cross sections were found to be approximately 1.8 times the p-p cross sections. Corrections were made for the shielding of nucleons within the deuteron so that the p-n interaction could be observed. The results indicate that the p-p and p-n cross sections are very nearly equal and that they satisfy the relations governed by charge independence. (auth)

Research Organization:
California. Univ., Berkeley. Lawrence Radiation Lab.
DOE Contract Number:
W-7405-ENG-48
NSA Number:
NSA-14-026198
OSTI ID:
4137943
Report Number(s):
UCRL-9288
Resource Relation:
Other Information: Orig. Receipt Date: 31-DEC-60
Country of Publication:
United States
Language:
English