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Your search keyword '"Hughes, R.O."' showing total 23 results
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23 results on '"Hughes, R.O."'

3. The hyperion particle-γ detector array

Author

Hughes, R.O., Harke, J.T., Casperson, R.J., Ota, S., Fisher, S., Parker, J., Beausang, C.W., Dag, M., Humby, P., Koglin, J., McCleskey, E., McIntosh, A.B., Saastamoinen, A., Tamashiro, A.S., Wilson, E., and Wu, T.C.

Published
2017
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7. Capture cross sections from (p,d) reactions

Author

Escher J.E., Burke J.T., Casperson R.J., Hughes R.O., Ota S., and Scielzo N.D.

Subjects
Physics, QC1-999
Abstract

Cross sections for compound-nuclear reactions involving unstable targets are important for many applications, but can often not be measured directly. Several indirect methods have been proposed to determine neutron capture cross sections for unstable isotopes. We consider an approach that aims at constraining statistical calculations of capture cross sections with data obtained from light-ion transfer reactions such as (p,d). We discuss the theoretical descriptions that have to be developed in order to extract meaningful cross section constraints from such data and show some benchmark results.

Published
2017
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8. Calculations of Compound Nucleus Spin-Parity Distributions Populated via the (p,t) Reaction in Support of Surrogate Neutron Capture Measurements

Author

Benstead J., Tostevin J.A., Escher J.E., Burke J.T., Hughes R.O., Ota S., Casperson R.J., and Thompson I.J.

Subjects
Physics, QC1-999
Abstract

The surrogate reaction method may be used to determine the cross section for neutron induced reactions not accessible through standard experimental techniques. This is achieved by creating the same compound nucleus as would be expected in the desired reaction, but through a different incident channel, generally a direct transfer reaction. So far, the surrogate technique has been applied with reasonable success to determine the fission cross section for a number of actinides, but has been less successful when applied to other reactions, e.g. neutron capture, due to a ‘spin-parity mismatch’. This mismatch, between the spin and parity distributions of the excited levels of the compound nucleus populated in the desired and surrogate channels, leads to differing decay probabilities and hence reduces the validity of using the surrogate method to infer the cross section in the desired channel. A greater theoretical understanding of the expected distribution of levels excited in both the desired and surrogate channels is therefore required in order to attempt to address this mismatch and allow the method to be utilised with greater confidence. Two neutron transfer reactions, e.g. (p,t), which allow the technique to be utilised for isotopes further removed from the line of stability, are the subject of this study. Results are presented for the calculated distribution of compound nucleus states populated in 90Zr, via the 90Zr(p,t)90Zr reaction, and are compared against measured data at an incident proton energy of 28.56 MeV.

Published
2016
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9. Exploring the spin states of 90Zr populated by (p,p’), (p,d), and (p,t) reactions

Author

Ota S., Burke J.T., Casperson R.J., Escher J.E., Hughes R.O., Ressler J.J., Scielzo N.D., Thompson I.J., Austin R.A.E., Abromeit B., Foley N.J., McCleskey E., McCleskey M., Park H. I., Saastamoinen A., and Ross T. J.

Subjects
Physics, QC1-999
Abstract

The 90Zr nucleus was produced by three different reactions: 90Zr(p,p’), 91Zr(p,d), and 92Zr(p,t), and the spin-parity (Jπ) population of the 90Zr states produced by these reactions was studied to investigate the surrogate reaction approach, which aims at indirectly determining cross sections for compound-nuclear reactions involving unstable targets such as 89Zr(n,γ). Discrete γ-rays, associated with the de-excitation of 90Zr and 89Zr, were measured in coincidence with light ions at 90Zr excitation energies extending above the neutron separation energy. Low-lying states populated by (p,d) and (p,t) reactions agreed well with the previous measurements. The measured γ transition systematics were used to gain insights into the Jπ distribution of 90Zr around the neutron separation energy and it was found that the (p,p’) reaction preferentially produces lower J states than (p,d) and (p,t) reactions in the studied energy region.

Published
2016
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10. 87Y(n,γ) and 89,90Zr(n,γ) cross sections from a surrogate reaction approach

Author

Ota Shuya, Burke J.T., Casperson R.J., Escher J.E., Hughes R.O., Ressler J.J., Scielzo N.D., Thompson I., Austin R.A.E., McCleskey E., McCleskey M., Saastamoinen A., and Ross T.

Subjects
Physics, QC1-999
Abstract

The surrogate reaction approach is an indirect method for determining nuclear reaction cross sections which cannot be measured directly or predicted reliably. While recent studies demonstrated the validity of the surrogate reaction approach for studying fission cross sections for short-lived actinides, its applicability for radiative neutron capture reactions ((n,γ)) is still under investigation. We studied the γ decay of excited 88Y and 90,91Zr nuclei produced by 89Y(p,d), 91Zr(p,d), and 92Zr(p,d) reactions, respectively, in order to infer the 87Y(n,γ) and 89, 90Zr(n,γ) cross sections. The experiments were carried out at the K150 Cyclotron facility at Texas A&M University with a 28.5-MeV proton beam. The reaction deuterons were measured at forward angles of 25-60° with the array of three segmented Micron S2 silicon detectors. The compound nuclei with energies up to a few MeV above the neutron separation thresholds were populated. The coincident γ-rays were measured with the array of five Compton-suppressed HPGe clover detectors.

Published
2015
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11. Validating (d,pγ) as a Surrogate for Neutron Capture

Author

Ratkiewicz A., Cizewski J.A., Pain S.D., Adekola A.S., Burke J.T., Casperson R.J., Fotiades N., McCleskey M., Burcher S., Shand C.M., Austin R.A.E., Baugher T., Carpenter M.P., Devlin M., Escher J.E., Hardy S., Hatarik R., Howard M.E., Hughes R.O., Jones K.L., Kozub R.L., Lister C.J., Manning B., O’Donnell J.M., Peters W.A., Ross T.J., Scielzo N.D., Seweryniak D., and Zhu S.

Subjects
Physics, QC1-999
Abstract

The r-process is responsible for creating roughly half of the elements heavier than iron. It has recently become understood that the rates at which neutron capture reactions proceed at late times in the r-process may dramatically affect the final abundance pattern. However, direct measurements of neutron capture reaction rates on exotic nuclei are exceptionally difficult, necessitating the development of indirect approaches such as the surrogate technique. The (d,pγ) reaction at low energies was identified as a promising surrogate for the (n,γ) reaction, as both reactions share many characteristics. We report on a program to validate (d,pγ) as a surrogate for (n,γ) using 95Mo as a target. The experimental campaign includes direct measurements of the γ-ray intensities from the decay of excited states populated in the 95Mo(n,γ) and 95Mo(d,pγ) reactions.

Published
2015
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12. Crystal structure of the tandem SAM domains from human SARM1

Author

Horsefield, S., primary, Burdett, H., additional, Zhang, X., additional, Manik, M.K., additional, Shi, Y., additional, Chen, J., additional, Tiancong, Q., additional, Gilley, J., additional, Lai, J., additional, Gu, W., additional, Rank, M., additional, Deerain, N., additional, Casey, L., additional, Ericsson, D.J., additional, Foley, G., additional, Hughes, R.O., additional, Bosanac, T., additional, von Itzstein, M., additional, Rathjen, J.P., additional, Nanson, J.D., additional, Boden, M., additional, Dry, I.B., additional, Williams, S.J., additional, Staskawicz, B.J., additional, Coleman, M.P., additional, Ve, T., additional, Dodds, P.N., additional, and Kobe, B., additional

Published
2019
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13. Crystal structure of the TIR domain from human SARM1 in complex with glycerol

Author

Horsefield, S., primary, Burdett, H., additional, Zhang, X., additional, Manik, M.K., additional, Shi, Y., additional, Chen, J., additional, Tiancong, Q., additional, Gilley, J., additional, Lai, J., additional, Gu, W., additional, Rank, M., additional, Deerain, N., additional, Casey, L., additional, Ericsson, D.J., additional, Foley, G., additional, Hughes, R.O., additional, Bosanac, T., additional, von Itzstein, M., additional, Rathjen, J.P., additional, Nanson, J.D., additional, Boden, M., additional, Dry, I.B., additional, Williams, S.J., additional, Staskawicz, B.J., additional, Coleman, M.P., additional, Ve, T., additional, Dodds, P.N., additional, and Kobe, B., additional

Published
2019
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14. Crystal structure of the TIR domain G601P mutant from human SARM1, crystal form 1

Author

Horsefield, S., primary, Burdett, H., additional, Zhang, X., additional, Manik, M.K., additional, Shi, Y., additional, Chen, J., additional, Tiancong, Q., additional, Gilley, J., additional, Lai, J., additional, Gu, W., additional, Rank, M., additional, Casey, L., additional, Ericsson, D.J., additional, Foley, G., additional, Hughes, R.O., additional, Bosanac, T., additional, von Itzstein, M., additional, Rathjen, J.P., additional, Nanson, J.D., additional, Boden, M., additional, Dry, I.B., additional, Williams, S.J., additional, Staskawicz, B.J., additional, Coleman, M.P., additional, Ve, T., additional, Dodds, P.N., additional, and Kobe, B., additional

Published
2019
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15. Crystal structure of the TIR domain H685A mutant from human SARM1

Author

Horsefield, S., primary, Burdett, H., additional, Zhang, X., additional, Manik, M.K., additional, Shi, Y., additional, Chen, J., additional, Tiancong, Q., additional, Gilley, J., additional, Lai, J., additional, Gu, W., additional, Rank, M., additional, Casey, L., additional, Ericsson, D.J., additional, Foley, G., additional, Hughes, R.O., additional, Bosanac, T., additional, von Itzstein, M., additional, Rathjen, J.P., additional, Nanson, J.D., additional, Boden, M., additional, Dry, I.B., additional, Williams, S.J., additional, Staskawicz, B.J., additional, Coleman, M.P., additional, Ve, T., additional, Dodds, P.N., additional, and Kobe, B., additional

Published
2019
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16. Crystal structure of the TIR domain from the grapevine disease resistance protein RUN1 in complex with NADP+ and Bis-Tris

Author

Horsefield, S., primary, Burdett, H., additional, Zhang, X., additional, Manik, M.K., additional, Shi, Y., additional, Chen, J., additional, Tiancong, Q., additional, Gilley, J., additional, Lai, J., additional, Gu, W., additional, Rank, M., additional, Casey, L., additional, Ericsson, D.J., additional, Foley, G., additional, Hughes, R.O., additional, Bosanac, T., additional, von Itzstein, M., additional, Rathjen, J.P., additional, Nanson, J.D., additional, Boden, M., additional, Dry, I.B., additional, Williams, S.J., additional, Staskawicz, B.J., additional, Coleman, M.P., additional, Ve, T., additional, Dodds, P.N., additional, and Kobe, B., additional

Published
2019
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17. Crystal structure of selenomethionine labelled tandem SAM domains (L446M:L505M:L523M mutant) from human SARM1

Author

Horsefield, S., primary, Burdett, H., additional, Zhang, X., additional, Manik, M.K., additional, Shi, Y., additional, Chen, J., additional, Tiancong, Q., additional, Gilley, J., additional, Lai, J., additional, Gu, W., additional, Rank, M., additional, Deerain, N., additional, Casey, L., additional, Ericsson, D.J., additional, Foley, G., additional, Hughes, R.O., additional, Bosanac, T., additional, von Itzstein, M., additional, Rathjen, J.P., additional, Nanson, J.D., additional, Boden, M., additional, Dry, I.B., additional, Williams, S.J., additional, Staskawicz, B.J., additional, Coleman, M.P., additional, Ve, T., additional, Dodds, P.N., additional, and Kobe, B., additional

Published
2019
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18. Crystal structure of the TIR domain G601P mutant from human SARM1, crystal form 2

Author

Horsefield, S., primary, Burdett, H., additional, Zhang, X., additional, Manik, M.K., additional, Shi, Y., additional, Chen, J., additional, Tiancong, Q., additional, Gilley, J., additional, Lai, J., additional, Gu, W., additional, Rank, M., additional, Casey, L., additional, Ericsson, D.J., additional, Foley, G., additional, Hughes, R.O., additional, Bosanac, T., additional, von Itzstein, M., additional, Rathjen, J.P., additional, Nanson, J.D., additional, Boden, M., additional, Dry, I.B., additional, Williams, S.J., additional, Staskawicz, B.J., additional, Coleman, M.P., additional, Ve, T., additional, Dodds, P.N., additional, and Kobe, B., additional

Published
2019
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19. Crystal structure of the TIR domain from human SARM1 in complex with ribose

Author

Horsefield, S., primary, Burdett, H., additional, Zhang, X., additional, Manik, M.K., additional, Shi, Y., additional, Chen, J., additional, Tiancong, Q., additional, Gilley, J., additional, Lai, J., additional, Gu, W., additional, Rank, M., additional, Deerain, N., additional, Casey, L., additional, Ericsson, D.J., additional, Foley, G., additional, Hughes, R.O., additional, Bosanac, T., additional, von Itzstein, M., additional, Rathjen, J.P., additional, Nanson, J.D., additional, Boden, M., additional, Dry, I.B., additional, Williams, S.J., additional, Staskawicz, B.J., additional, Coleman, M.P., additional, Ve, T., additional, Dodds, P.N., additional, and Kobe, B., additional

Published
2019
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20. In-beam γ -ray spectroscopy studies of medium-spin states in the odd-odd nucleus Re 186

Author

Ideguchi, E., Janssens, R.V.F., Hoffman, C.R., McClory, J.W., Lauritsen, T., Dracoulis, G.D., Wilson, A.N., Watanabe, H., Odahara, A., Nieminen, P., Noji, S., Stuchbery, A.E., Ong, H.J., Chiara, C.J., Fang, Y.D., Tran, D.T., Lane, G.J., Byrne, A.P., Carpenter, M.P., Kondev, F.G., Kanaya, S., Davidson, P.M., Hughes, R.O., Carroll, J.J., Matters, D.A., Kibédi, T., Kay, B.P., Aoi, N., Ayyad, Y., Zhu, S., and Yamamoto, Y.

Abstract

Excited states in Re186 with spins up to J=12 were investigated in two separate experiments using W186(d,2n) reactions at beam energies of 12.5 and 14.5 MeV. Two- and threefold γ-ray coincidence data were collected using the CAESAR and CAGRA spectrometers, respectively, each composed of Compton-suppressed high-purity germanium detectors. Analysis of the data revealed rotational bands built on several two-quasiparticle intrinsic states, including a long-lived Kπ=(8+) isomer. Configuration assignments were supported by an analysis of in-band properties, such as gK-gR values. The excitation energies of the observed intrinsic states were compared with results from multi-quasiparticle blocking calculations, based on the Lipkin-Nogami pairing approach, that included contributions from the residual proton-neutron interactions.

Published
2017
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22. Exploring the spin states of90Zr populated by (p,p’), (p,d), and (p,t) reactions

Author

Ota, S., primary, Burke, J.T., additional, Casperson, R.J., additional, Escher, J.E., additional, Hughes, R.O., additional, Ressler, J.J., additional, Scielzo, N.D., additional, Thompson, I.J., additional, Austin, R.A.E., additional, Abromeit, B., additional, Foley, N.J., additional, McCleskey, E., additional, McCleskey, M., additional, Park, H. I., additional, Saastamoinen, A., additional, and Ross, T. J., additional

Published
2016
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23. 87Y(n,γ) and89,90Zr(n,γ) cross sections from a surrogate reaction approach

Author

Ota, Shuya, primary, Burke, J.T., additional, Casperson, R.J., additional, Escher, J.E., additional, Hughes, R.O., additional, Ressler, J.J., additional, Scielzo, N.D., additional, Thompson, I., additional, Austin, R.A.E., additional, McCleskey, E., additional, McCleskey, M., additional, Saastamoinen, A., additional, and Ross, T., additional

Published
2015
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