Quasielastic scattering using the (p,n) reaction at 795 MeV

Thesis/Dissertation · Sat Aug 01 04:00:00 EDT 1992

OSTI ID:10174082

Prout, D L

A survey in nuclear mass and in momentum transfer of cross sections and analyzing powers in the quasielastic region has been made using the (p,n) reaction. The measurements were performed at an energy of 795 MeV at the Neutron Time of Flight Facility and the Weapons Neutron Research line at LAMPF. The (p,n) reaction isolates the isovector ({rvec {tau}}{sub 1} {center_dot} {rvec {tau}}{sub 2}) part of the nucleon nucleus interaction. Standard models of quasielastic scattering were able to describe the magnitude and shape of the double differential cross sections very well if account was taken of a significant background from double scattering. In contrast, the quasielastic response was shifted to much higher excitation energy than what was expected. This was true for all nuclei at moderate to large momenta transfers. Neither the Coulomb energy shift nor RPA calculations with the standard particle hole (p-h) interactions could account for this large shift. The data argue for a repulsive interaction in both the transverse and longitudinal channels of the p-h interaction. A suppression of the quasielastic analyzing power compared to the free nucleon nucleon analyzing power was found in {sup nat}C at all the angles measured. The same region in {sup nat}Pb showed little or no suppression. Part of the suppression in the {sup nat}C data may be accounted for by relativistic models of the nucleus employing large vector and scalar potentials with an effective mass of .85 times the free nucleon mass. The relatively larger contribution of double scattering {sup nat}Pb({rvec p}, n) than to {sup nat}C({rvec p}, n) may account for the difference in analyzing power for these two targets in the quasielastic region.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 10174082
• Report Number(s): LA--12360-T; ON: DE92040323
• Country of Publication: United States
• Language: English

Related Subjects

663430
663520
663580
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
A = 190-219
A = 6-19
ANALYZING POWER
CARBON
CROSS SECTIONS
DATA ACQUISITION SYSTEMS
LEAD
MOMENTUM TRANSFER
NUCLEON-INDUCED REACTIONS AND SCATTERING
NUCLEON-NUCLEON INTERACTIONS
PROTON REACTIONS
QUASI-ELASTIC SCATTERING