Inner hole states in /sup 207/Pb via the /sup 208/Pb(/sup 3/He,. cap alpha. ) /sup 207/Pb reaction at 70 MeV

Journal Article · Thu Nov 30 23:00:00 EST 1978 · Phys. Rev., C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.18.2475· OSTI ID:6505327

Gales, S; Crawley, G M; Weber, D; Zwieglinski, B

The /sup 208/Pb(/sup 3/He,..cap alpha..)/sup 207/Pb reaction at 70 MeV incident energy was used to populate hole states up to 28 MeV excitation energy in /sup 207/Pb. A split-pole spectrometer was used for particle analysis and detection. For the excitation energy range between 0 to 4.5 MeV, about eleven well resolved states are excited. These levels contain the main part of the spectroscopic strengths of the 3p/sub 1/2/, 2f/sub 5/2/, 3p/sub 3/2/, 2f/sub 7/2/, 1i/sub 13/2/, and 1h/sub 9/2/ neutron subshells. Three additional regions of enhanced cross sections, centered at 5.5, 8.5, and 14 MeV excitation energy in /sup 207/Pb, are also observed. The 65 keV energy resolution of the present study revealed fine structure in the peak previously observed around 8.5 MeV in /sup 207/Pb. About fifteen levels or groups of levels are populated between 4.5 and 10.5 MeV, and angular distributions have been extracted for each individual peak as well as for the gross structures. A distorted-wave Born-approximation analysis of the data was carried out and shows that the missing l = 3 and 5 strengths in /sup 207/Pb are located in some strong peaks at 5.13, 5.62, and 6.37 MeV. Thus the full sum rule is obtained for the neutron subshells between N = 126 and N = 82. The highly fragmented peak located at 8.5 MeV excitation energy is shown to arise from 1h/sub 11/2/ neutron pickup. Finally, the large structure, 7 MeV wide and centered around 14 MeV, observed for the first time in this work is tentatively interpreted as arising from neutron pickup from the 1g/sub 9/2/ inner shell. The T/sub greater-than/ components of the deeply-bound state are also observed between 20 to 24 MeV in /sup 207/Pb and therefore from the sum-rule analysis, centroid energies and total strengths for each inner subshell are deduced.

• Research Organization: Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824
• OSTI ID: 6505327
• Journal Information: Phys. Rev., C; (United States), Journal Name: Phys. Rev., C; (United States) Vol. 18:6; ISSN PRVCA
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA SPECTRA
ANGULAR MOMENTUM
BORN APPROXIMATION
CHARGED-PARTICLE REACTIONS
CROSS SECTIONS
DIRECT REACTIONS
DWBA
ENERGY LEVELS
ENERGY RANGE
EQUATIONS
EVEN-ODD NUCLEI
HEAVY NUCLEI
HELIUM 3 REACTIONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LEAD 207
LEAD 208 TARGET
LEAD ISOTOPES
MAGNETIC SPECTROMETERS
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
MEV RANGE
MEV RANGE 10-100
NUCLEAR MODELS
NUCLEAR REACTIONS
NUCLEI
ONE-NUCLEON TRANSFER REACTIONS
PARITY
PARTICLE PROPERTIES
PICKUP REACTIONS
RADIOISOTOPES
SECONDS LIVING RADIOISOTOPES
SHELL MODELS
SPECTRA
SPECTROMETERS
SPECTROSCOPIC FACTORS
SPIN
STABLE ISOTOPES
SUM RULES
TARGETS
TRANSFER REACTIONS