K-shell ionization in proton-barium collisions accompanied by resonance reactions

Miscellaneous · Fri Jan 01 00:00:00 EST 1988

OSTI ID:6903713

Spooner, D W

The effects of nuclear reactions on inner-shell ionization of atoms were studied with protons incident upon isotopically enriched barium targets. A cooled detector system, capable of identifying protons responsible for K-shell ionization in zero-impact-parameter collisions, was developed to measure coincidences between Ba x-rays and protons scattered to an angle of 172{degree}. Several aspects of atomic ionization were investigated by this method. A very large (>200%) variation of the K-shell ionization probability (P{sub k}) was observed in elastic scattering of protons from {sup 138}Ba as the proton energy was tuned across an isobaric analog resonance (IAR) at 10.0 MeV. Measurements of the energy dependence of P{sub K} during inelastic IAR scattering to the first excited state of {sup 138}Ba were performed. The data are in good agreement with the behavior predicted for this system, in which the ionization process is modified both by the interference effect and the reduced velocity of the particle on the way out of the collision. The effects of compound-inelastic scattering are considered. Compound-nucleus (CN) x-rays were detected in elastic and inelastic proton scattering at projectile energies near the isobaric analog resonance at 9.3 MeV in {sup 134}Ba. The observed ratio of CN x-rays to target x-rays in elastic scattering, 0.05 {plus minus} 0.03, is consistent with a compound-elastic cross section of 4.0 {plus minus} 1.0 mb/sr which is obtained from a fit to the elastic scattering excitation function. A compound-nucleus lifetime of (18{plus minus} {sup 27}{sub 11}) {center dot} 10{sup {minus}17} sec is determined, corresponding to a nuclear level width of 1 {plus minus} {sup 2}{sub 0.6} eV.

• Research Organization: Stanford Univ., CA (USA)
• OSTI ID: 6903713
• Resource Relation: Other Information: Thesis (Ph. D)
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BARIUM
ION-ATOM COLLISIONS
BARIUM 138 TARGET
PROTON REACTIONS
HYDROGEN IONS 1 PLUS
CROSS SECTIONS
ENERGY LOSSES
IONIZATION
ISOBARIC ANALOGS
MEV RANGE 01-10
SCATTERING
X RADIATION
ALKALINE EARTH METALS
ATOM COLLISIONS
BARYON REACTIONS
CATIONS
CHARGED PARTICLES
CHARGED-PARTICLE REACTIONS
COLLISIONS
ELECTROMAGNETIC RADIATION
ELEMENTS
ENERGY LEVELS
ENERGY RANGE
HADRON REACTIONS
HYDROGEN IONS
ION COLLISIONS
IONIZING RADIATIONS
IONS
LOSSES
METALS
MEV RANGE
NUCLEAR REACTIONS
NUCLEON REACTIONS
RADIATIONS
TARGETS
640304* - Atomic
Molecular & Chemical Physics- Collision Phenomena
651720 - Nuclear Properties & Reactions
A=90-149
Experimental