Title: Measurement of the ${}^{115}\mathrm{In} (\gamma ,{\gamma }^{\text{'}}){}^{115m}\mathrm{In}$ inelastic scattering cross section in the 1.8 to 3.7 MeV energy range with monoenergetic photon beams

Abstract

For the first time the excitation cross section of $$^{115}\mathrm{In}$$ to its first excited state at 336.24 keV has been measured with monoenergetic photon beams at 15 energies between 1.8 and 3.7 MeV. The measurements were performed at the High-Intensity Gamma-ray Source ($$\mathrm{HI}{\gamma}\mathrm{S}$$) facility with natural In targets and incident photon fluxes ranging from $$0.7\times{}{10}^{7}{\gamma}/({\mathrm{cm}}^{2}{s})$$ to $$3.2\times{}{10}^{7}{\gamma}/({\mathrm{cm}}^{2}{s})$$. The inelastic scattering cross section was obtained from the yield of the 336.24 keV deexcitation $${\gamma}$$ rays. The cross-section values varied between < 0.05 and 28.7 $${\mu}\mathrm{b}$$ at 1.8 and 3.7 MeV, respectively. Compared to standard photon inelastic scattering cross-section data in this energy range of medium-mass nuclei, these extremely small values are not completely unexpected, given the nature of the low-lying nuclear levels of $$^{115}\mathrm{In}$$. Model calculations, however, overestimate the measured cross-section data by approximately one order of magnitude. Using different choices for the $$E1 {\gamma}$$-ray strength function, the data can be well described. Finally, the data are important for improving our knowledge of the level scheme of $$^{115}\mathrm{In}$$, especially spin and parity assignments of already known states.

Authors:

Tornow, W. ^[1]; Bhike, M. ^[1]; Finch, S. W. ^[1]; Krishichayan, . ^[1]; Tonchev, A. P. ^[2]

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+ Show Author Affiliations

1. Duke Univ., Durham, NC (United States). Dept. of Physics; Triangle Universities Nuclear Lab., Durham, NC (United States)
2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Nuclear and Chemical Sciences Division

Publication Date:

Thu Dec 06 00:00:00 EST 2018

Research Org.:

Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Duke Univ., Durham, NC (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Nuclear Physics (NP)

OSTI Identifier:

1529175

Alternate Identifier(s):

OSTI ID: 1484685; OSTI ID: 1484826

Report Number(s):

LLNL-JRNL-759602
Journal ID: ISSN 2469-9985; PRVCAN; 947977

Grant/Contract Number:  

AC52-07NA27344; FG02-97ER41033

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review C

Additional Journal Information:

Journal Volume: 98; Journal Issue: 6; Journal ID: ISSN 2469-9985

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

73 NUCLEAR PHYSICS AND RADIATION PHYSICS; electromagnetic transitions; energy levels & level densities; nuclear reactions; nuclear spin & parity; photonuclear reactions