Absence of isoscalar monopole strength in {sup 56}Fe and {sup 58}Ni

Journal Article · Sun Oct 01 04:00:00 EDT 1995 · Bulletin of the American Physical Society

OSTI ID:256473

Clark, H L; Lui, W; Youngblood, D H

Measurements with 240 MeV {alpha} particle inelastic scattering with excellent peak/background ratios at small scattering angles including 0{degrees} were made on {sup 56}Fe and {sup 58}Ni using the multipole-dipole-multipole spectrometer at Texas A&M University. Beam was delivered to the spectrometer through a beam analysis system having two bends of 88{degrees} and 87{degrees} respectively. A slit placed after the first 88{degrees} bend was used to define the beam. Slits placed after the second bend (87{degrees}) were used to eliminate slit scattered particles. Comparison of the results of a multiple peak fit to the{sup 58}Ni spectra after continuum subtraction to DWBA calculations revealed about 32% of the E0 EWSR and 58% of the E2 EWSR in the peak, in agreement with previous works. Fits to the angular distribution of the continuum for E{sub x} = 25 MeV show that <15% of the E0 EWSR is present in the continuum. Hence 50% of the EO EWSR must lie above E{sub x} = 25 MeV in {sup 58}Ni. Similar results were obtained for {sup 56}Fe. Reasonable assumptions then lead to a lower limit for the centroid of the GMR strength of 25 MeV in {sup 58}Ni which corresponds to E{sub x}>96/A{sup 1/3} much higher than the approximately 80/A{sup 1/3} expected.

• OSTI ID: 256473
• Report Number(s): CONF-9510116--
• Journal Information: Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 10 Vol. 40; ISSN 0003-0503; ISSN BAPSA6
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ALPHA REACTIONS
DWBA
INELASTIC SCATTERING
IRON 56
NICKEL 58