Measurements of the neutron transmission and capture cross sections in /sup 204/Pb

Journal Article · Fri Jun 01 00:00:00 EDT 1984 · Phys. Rev. C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.29.2126· OSTI ID:6528446

Horen, D J; Macklin, R L; Harvey, J A; Hill, N W

High resolution neutron transmission measurements have been performed on /sup 204/Pb in the energy interval E = 0.4--105 keV. The transmission data were analyzed using a multilevel R-matrix code to deduce resonance parameters. Previously obtained neutron capture data were reanalyzed in the interval 2.6--86 keV. Values of GGAMMA/sub n/GAMMA/sub ..gamma..//GAMMA were determined from the capture data. For those resonances where GAMMA/sub n/ could be determined from the transmission data, the capture data were analyzed to extract GAMMA/sub ..gamma../. Our results yield an average capture for a stellar temperature kT = 30 keV of 89.5 +- 4.5 mb. The s-wave level density for /sup 205/Pb corresponding to the neutron energy range investigated (i.e., Eapprox.105 keV) relative to that for /sup 207/Pb (which has about the same neutron separation energy) is greater by about a factor of 10. The average s-wave strength function in this energy region is determined as S/sub 0/ = 0.93 x 10/sup -4/. This is an order of magnitude greater than that for a similar energy region in /sup 206/Pb+n where a doorway is observed at Eapprox.500 keV. However, the strength function in the initial E = 0--100 keV in /sup 204/Pb+n is almost identical to the average value of that for /sup 206/Pb+n when the averaging interval for the latter is taken as E/sub n/roughly-equal0--1000 keV (i.e., over the doorway state). This suggests that the s-wave doorway state observed in the higher mass lead isotopes is completely mixed with ''background'' states in /sup 205/Pb, and most likely no intermediate structure will be observed in the s-wave strength function for the /sup 204/Pb+n reaction.

• Research Organization: Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
• OSTI ID: 6528446
• Journal Information: Phys. Rev. C; (United States), Journal Name: Phys. Rev. C; (United States) Vol. 29:6; ISSN PRVCA
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BARYON REACTIONS
BETA DECAY RADIOISOTOPES
CAPTURE
DATA
ELECTRON CAPTURE RADIOISOTOPES
ENERGY LEVELS
ENERGY RANGE
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
FUNCTIONS
HADRON REACTIONS
HEAVY NUCLEI
INFORMATION
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
KEV RANGE
LEAD 204 TARGET
LEAD 205
LEAD ISOTOPES
MATRICES
NEUTRON REACTIONS
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
NUMERICAL DATA
PARTIAL WAVES
R MATRIX
RADIOISOTOPES
RESONANCE
S WAVES
SECONDS LIVING RADIOISOTOPES
STRENGTH FUNCTIONS
TARGETS
TRANSMISSION
YEARS LIVING RADIOISOTOPES