Benchmarking a surrogate reaction for neutron capture

Hatarik, R.; Bernstein, L. A.; Cizewski, J. A.; Bleuel, D. L.; Burke, J. T.; Escher, Jutta; Gibelin, J.; Goldblum, B. L.; Hatarik, A. M.; Lesher, S. R.; O’Malley, P. D.; Phair, L.; Rodriguez‐Vieitez, Elena; Swan, T.; Wiedeking, M.

doi:10.1103/physrevc.81.011602

Cited by 31 publications

(49 citation statements)

References 27 publications

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“…While this has a smaller effect on the extraction of fission cross sections [9], the γ-ray emission of the compound nucleus can be quite sensitive to the initial J π distribution [14,15,[17][18][19][20][21]. Therefore, in order to extract (n, γ) cross sections from surrogate data it becomes necessary to take into account the J π distribution of the decaying compound nucleus.…”

Section: Introductionmentioning

confidence: 99%

Spin differences in the Zr90 compound nucleus induced by (p,p′) ,
Ota
¹
,
Burke
²
,
Casperson
³

et al. 2015
Phys. Rev. C
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The effect of the production mechanism on the decay of a compound nucleus is investigated. The nucleus 90 Zr was produced by three different reactions, namely 90 Zr(p, p ) 90 Zr, 91 Zr(p, d) 90 Zr, and 92 Zr(p, t) 90 Zr, which served as surrogate reactions for 89 Zr(n, γ). The spin-parity (J π ) distributions of the states populated by these reactions were studied to investigate the surrogate reaction approach, which aims at indirectly determining cross sections for compound-nuclear reactions involving unstable targets such as 89 Zr. Discrete γ-rays, associated with transitions in 90 Zr and 89 Zr, were measured in coincidence with light ions for scattering angles of 25-60 • and 90 Zr excitation energies extending above the neutron separation energy. The measured transition systematics were used to gain insights into the J π distributions of 90 Zr. The 90 Zr(p, p ) reaction was found to produce fewer γ-rays associated with transitions involving high spin states (J = 6-8 ) than the other two reactions, suggesting that inelastic scattering preferentially populates states in 90 Zr that have lower spins than those populated in the transfer reactions investigated. The γ-ray production was also observed to vary by factors of 2-3 with the angle at which the outgoing particle was detected. These findings are relevant to the application of the surrogate reaction approach.

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Section: Introductionmentioning

confidence: 99%

Spin differences in the Zr90 compound nucleus induced by (p,p′) ,
Ota
¹
,
Burke
²
,
Casperson
³

et al. 2015
Phys. Rev. C
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“…The question then arises as to why our surrogate 232 Th(n,γ) cross section data show good agreement with the direct measurements in the 500 keV-1 MeV range, when other (n,γ) surrogate measurements (e.g. Scielzo et al [10]) do not. This may be due to the fact that level densities in the actinides are higher and thus decay probabilities are not as sensitive to differences in entry spin distributions as in the lanthanides.…”

Section: Resultsmentioning

confidence: 99%

“…It was shown that the likely explanation of the observed discrepancies was due to the strong spin-dependence of the decay probability at low energies, and hence any angular momentum mismatch between the direct and indirect reactions would produce a large difference in the indirect and direct measurements because the highest l-waves favor gamma decay leading to an overestimate of the cross section. Hatarik et al [10] have proposed a method where this overestimation of the decay probability is corrected via the subtraction of components from higher spin states and appears to be a promising line of further inquiry.…”

Section: Resultsmentioning

confidence: 99%

“…Another (n,γ) measurement has been performed using the surrogate ratio method (SRM) to extract indirectly the 235 U(n,γ) cross section [6]. The surrogate ratio method [7,8,9,10] is a different technique which relies on a comparison of two neighboring final nuclei created under the same experimental conditions, where one of the surrogate cross sections is known from direct measurements.…”

Section: Introductionmentioning

confidence: 99%

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Indirect (n,γ) cross sections of thorium cycle nuclei using the surrogate method

et al. 2012

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Indirect neutron capture (n,γ) cross sections have been extracted for the key thorium cycle nuclei 232 Th, 231 Pa and 230 Th using the surrogate reaction method. Final nucleus gamma decay probabilities were measured between the neutron binding energy and around 1MeV above it using the 232 Th(d,p) 233 Th, 232 Th( 3 He,t) 232 Pa and 232 Th( 3 He,α) 231 Th reactions in experiments with the Cactus gamma-detector array and Silicon Ring charged particle detectors at the Oslo Cyclotron Laboratory. Since the neutron capture cross section for 232 Th is already well known from direct measurements a comparison with these results provides a stringent test of the applicability of the surrogate method in the actinide region for indirect (n,γ) cross section measurements. In addition, a new technique for correcting measured gamma ray decay probabilities below the neutron emission energy threshold is proposed and used. We find good agreement between indirect and direct (n,γ) cross section measurements in the range 500 keV -1 MeV, but large discrepancies outside this range. Explanations for the observed differences are proposed. PACS number(s): 24.87.+y, 24.10.-i, 25.45.-z, 25.55.-e

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“…This effort was recently expanded to include the determination of neutron capture cross sections. Two approaches have been applied to tag the γ-decay channel in the indirect determination of neutron capture cross sections using the surrogate method: discrete tagging [8][9][10][11] and statistical tagging [12,13].…”

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confidence: 99%

Indirect determination of neutron capture cross sections on spherical and near-spherical nuclei using the surrogate method

et al. 2012

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The 92 Mo(n,γ) cross section was obtained using both the absolute surrogate approach and surrogate ratio method (SRM), relative to the 94 Mo(n,γ) cross section, in an equivalent neutron energy range of 80 to 890 keV. Excited 93 Mo and 95 Mo nuclei were populated using the 92 Mo(d, p) and 94 Mo(d, p) reactions, respectively. Both discrete and statistical tagging approaches were employed to identify the γ-decay channel and were examined in terms of their sensitivity to the initial angular momentum population distribution. The absolute surrogate 92 Mo(n,γ) cross sections disagree with evaluated neutron capture cross section data by as much as a factor of four, whereas the results obtained using the SRM trend more favorably with the evaluated result. Experimental results suggest that discrete and statistical tagging approaches may sample different contributions of the γ-cascade for near-spherical nuclei. This work represents the first use of the surrogate method in the determination of neutron capture cross sections on spherical and quasi-spherical nuclei in the mass-90 region and provides a possible pathway to extend the SRM to a broader mass range.

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Benchmarking a surrogate reaction for neutron capture

Cited by 31 publications

References 27 publications

Spin differences in the Zr90 compound nucleus induced by (p,p′) ,
Ota
¹
,
Burke
²
,
Casperson
³

et al. 2015
Phys. Rev. C
Self Cite
23
3
28
0
View full text Add to dashboard Cite

Spin differences in the Zr90 compound nucleus induced by (p,p′) ,
Ota
¹
,
Burke
²
,
Casperson
³

et al. 2015
Phys. Rev. C
Self Cite
23
3
28
0
View full text Add to dashboard Cite

Indirect (n,γ) cross sections of thorium cycle nuclei using the surrogate method

Indirect determination of neutron capture cross sections on spherical and near-spherical nuclei using the surrogate method

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Benchmarking a surrogate reaction for neutron capture

Cited by 31 publications

References 27 publications

Spin differences in the Zr90 compound nucleus induced by (p,p′) , Ota1, Burke2, Casperson3 et al. 2015Phys. Rev. CSelf Cite233280View full textAdd to dashboardCite

Spin differences in the Zr90 compound nucleus induced by (p,p′) , Ota1, Burke2, Casperson3 et al. 2015Phys. Rev. CSelf Cite233280View full textAdd to dashboardCite

Indirect (n,γ) cross sections of thorium cycle nuclei using the surrogate method

Indirect determination of neutron capture cross sections on spherical and near-spherical nuclei using the surrogate method

Contact Info

Product

Resources

About

Spin differences in the Zr90 compound nucleus induced by (p,p′) ,
Ota
¹
,
Burke
²
,
Casperson
³

et al. 2015
Phys. Rev. C
Self Cite
23
3
28
0
View full text Add to dashboard Cite

Spin differences in the Zr90 compound nucleus induced by (p,p′) ,
Ota
¹
,
Burke
²
,
Casperson
³

et al. 2015
Phys. Rev. C
Self Cite
23
3
28
0
View full text Add to dashboard Cite