Shell structure at N=28 near the dripline: Spectroscopy of {sup 42}Si, {sup 43}P, and {sup 44}S

Journal Article · Fri Sep 15 04:00:00 EDT 2006 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.74.034313· OSTI ID:20863785

Fridmann, J; Wiedenhoever, I; Baby, L T; Cottle, P D; Diffenderfer, E; Kemper, K W ^[1]; Gade, A; Bazin, D; Brown, B A; Campbell, C M; Cook, J M; Dinca, D -C; Glasmacher, T; Hansen, P G; Lecouey, J L; Mueller, W F; Terry, J R; Yoneda, K; Zwahlen, H ^[2]; Rodriguez-Vieitez, E ^[3]

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1. Department of Physics, Florida State University, Tallahassee, Florida 32306-4350 (United States)
2. National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824-1321 (United States)
3. Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

Measurements of the N=28 isotones {sup 42}Si, {sup 43}P, and {sup 44}S using one- and two-proton knockout reactions from the radioactive beam nuclei {sup 44}S and {sup 46}Ar are reported. The knockout reaction cross sections for populating {sup 42}Si and {sup 43}P and a 184 keV {gamma}-ray observed in {sup 43}P establish that the d{sub 3/2} and s{sub 1/2} proton orbits are nearly degenerate in these nuclei and that there is a substantial Z=14 subshell closure separating these two orbits from the d{sub 5/2} orbit. The increase in the inclusive two-proton knockout cross section from {sup 42}Si to {sup 44}S demonstrates the importance of the availability of valence protons for determining the cross section. New calculations of the two-proton knockout reactions that include diffractive effects are presented. In addition, it is proposed that a search for the d{sub 5/2} proton strength in {sup 43}P via a higher statistics one-proton knockout experiment could help determine the size of the Z=14 closure.

• OSTI ID: 20863785
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 3 Vol. 74; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ARGON 46
CROSS SECTIONS
GAMMA RADIATION
ISOTONIC NUCLEI
KEV RANGE
KNOCK-OUT REACTIONS
NUCLEAR STRUCTURE
ORBITS
PHOSPHORUS 43
PROTONS
SILICON 42
SPECTROSCOPY
STATISTICS
VALENCE