Stellar krypton cross sections at kT = 25 and 52 keV

Journal Article · Sun Mar 01 04:00:00 EST 1987 · Phys. Rev. C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.35.936· OSTI ID:6003708

Kaeppeler, F; Naqvi, A A; Al-Ohali, M

Studies of neutron capture nucleosynthesis in the s process usually refer to a thermal energy of kT = 30 keV, corresponding to a temperature of T = 3.5 x 10/sup 8/ K. This convention is justified as stellar neutron capture rates are in general not sensitive to temperature because of the approximate E/sub n//sup -1/2/ dependence of most capture cross sections. But several important exceptions of this rule require more detailed information on the variation of the average stellar cross section with temperature. We show that activation measurements can be performed in a quasistellar neutron spectrum for kT = 52 keV, using kinematically collimated neutrons from the /sup 3/H(p,n) reaction. Neutron capture cross sections were measured in this spectrum and at kT = 25 keV for /sup 86/Kr(n,..gamma..) and for the reaction /sup 84/Kr(n,..gamma..) /sup 85/Kr/sup m/, which populates the isomeric state in /sup 85/Kr. In this way, the respective 30 keV cross sections of 3.5 +- 0.3 and 16.7 +- 1.2 mb could be derived by interpolation.

• Research Organization: Kernforschungszentrum Karlsruhe, Institut fuer Kernphysik, D-7500 Karlsruhe, Federal Republic of Germany
• OSTI ID: 6003708
• Journal Information: Phys. Rev. C; (United States), Journal Name: Phys. Rev. C; (United States) Vol. 35:3; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

651620* -- Nuclear Properties & Reactions
A=59-89
Experimental
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BARYON REACTIONS
CAPTURE
CROSS SECTIONS
ENERGY DEPENDENCE
GAMMA SPECTRA
HADRON REACTIONS
KRYPTON 84 TARGET
KRYPTON 86 TARGET
NEUTRON REACTIONS
NEUTRON SPECTRA
NUCLEAR REACTIONS
NUCLEON REACTIONS
NUCLEOSYNTHESIS
S PROCESS
SPECTRA
STAR EVOLUTION
SYNTHESIS
TARGETS