Proton resonance spectroscopy in sup 40 Ca

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:5594893

Warthen, B J

The differential cross sections for the {sup 39}K(p,p{sub o}){sup 39}K and {sup 39}K-(p,{alpha}{sub o}){sup 36}Ar reactions have been measured for E{sub p} = 1.90 to 4.02 MeV at laboratory angles {theta} = 90{degree}, 108{degree}, 150{degree} and 165{degree}. Data were taken with the Triangle Universities Nuclear Laboratory (TUNL) KN Van de Graaff accelerator and the associated high resolution system. The targets consisted of 1-2 {mu}g/cm{sup 2} of potassium carbonate (K{sub 2}CO{sub 3}), enriched to 99.97% {sup 39}K, evaporated onto gold coated carbon backings. Excitation functions were measured in proton energy steps varying from 100 to 400 3V. The energy region studied corresponds to an excitation energy range in the {sup 40}Ca nucleus of E{sub x} = 10.2 to 12.3 MeV. A multi-level multi-channel R-matrix based computer code was used to fit the experimental excitation functions. Resonance parameters obtained include resonance energy, spin, parity, partial widths, and channel spin and orbital angular momentum mixing ratios. Of the 248 resonances observed in the proton channel, 148 were also observed in the alpha channel. A fit to the observed level density yielded a nuclear temperature of 1.5 MeV. The data were compared with predictions of statistical theories of energy levels for both level spacing and reduced width distributions. The alpha reduced widths agree with the Porter-Thomas distribution and suggest that only 5-10% of the states with alpha widths were not observed. The summed strength in each of the alpha channels represents a significant fraction of the Wigner limit for these channels. The proton channels, on the other hand, generally have much smaller fractions. The two proton s-wave strength functions are equal and thus show no evidence for spin-exchange forces in the nucleon-nucleus interaction.

• Research Organization: Duke Univ., Durham, NC (USA)
• OSTI ID: 5594893
• Country of Publication: United States
• Language: English

Related Subjects

651520* -- Nuclear Properties & Reactions
A=39-58
Experimental
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALKALINE EARTH ISOTOPES
ALPHA PARTICLES
ANGULAR MOMENTUM
ARGON 36
ARGON ISOTOPES
BARYON REACTIONS
BARYON-BARYON INTERACTIONS
CALCIUM 40
CALCIUM ISOTOPES
CHARGED PARTICLES
CHARGED-PARTICLE REACTIONS
COMPARATIVE EVALUATIONS
CROSS SECTIONS
DATA
DIFFERENTIAL CROSS SECTIONS
DIRECT REACTIONS
ELASTIC SCATTERING
ENERGY RANGE
EVEN-EVEN NUCLEI
EXCITATION FUNCTIONS
EXPERIMENTAL DATA
FUNCTIONS
HADRON REACTIONS
HADRON-HADRON INTERACTIONS
INFORMATION
INTERACTIONS
ISOTOPES
LIGHT NUCLEI
MATRICES
MEV RANGE
MEV RANGE 01-10
MIXING RATIO
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
NUCLEON-NUCLEON INTERACTIONS
NUMERICAL DATA
PARITY
PARTICLE INTERACTIONS
PARTICLE PROPERTIES
PICKUP REACTIONS
POTASSIUM 39 TARGET
PROTON REACTIONS
R MATRIX
RESONANCE
SCATTERING
SPECTROSCOPY
SPIN
SPIN EXCHANGE
STABLE ISOTOPES
TARGETS
TRANSFER REACTIONS