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Your search keyword '"Carroll, J. J."' showing total 5 results
Start Over Author "Carroll, J. J." Topic nuclear theory
5 results on '"Carroll, J. J."'

1. Measurement of the Isolated Nuclear Two-Photon Decay in $^{72}\mathrm{Ge}$

Author

Freire-Fernández, D., Korten, W., Chen, R. J., Litvinov, S., Litvinov, Yu. A., Sanjari, M. S., Weick, H., Akinci, F. C., Albers, H. M., Armstrong, M., Banerjee, A., Blaum, K., Brandau, C., Brown, B. A., Bruno, C. G., Carroll, J. J., Chen, X., Chiara, Ch. J., Cortes, M. L., Dellmann, S. F., Dillmann, I., Dmytriiev, D., Forstner, O., Geissel, H., Glorius, J., Görgen, A., Górska, M., Griffin, C. J., Gumberidze, A., Harayama, S., Hess, R., Hubbard, N., Ide, K. E., John, Ph. R., Joseph, R., Jurado, B., Kalaydjieva, D., Kanika, K., Kondev, F. G., Koseoglou, P., Kosir, G., Kozhuharov, Ch., Kulikov, I., Leckenby, G., Lorenz, B., Marsh, J., Mistry, A., Ozawa, A., Pietralla, N., Podolyák, Zs., Polettini, M., Sguazzin, M., Sidhu, R. S., Steck, M., Stöhlker, Th., Swartz, J. A., Vesic, J., Walker, P. M., Yamaguchi, T., and Zidarova, R.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

The nuclear two-photon or double-gamma ($2\gamma$) decay is a second-order electromagnetic process whereby a nucleus in an excited state emits two gamma rays simultaneously. To be able to directly measure the $2\gamma$ decay rate in the low-energy regime below the electron-positron pair-creation threshold, we combined the isochronous mode of a storage ring with Schottky resonant cavities. The newly developed technique can be applied to isomers with excitation energies down to $\sim100$\,keV and half-lives as short as $\sim10$\,ms. The half-life for the $2\gamma$ decay of the first-excited $0^+$ state in bare $^{72}\mathrm{Ge}$ ions was determined to be $23.9\left(6\right)$\,ms, which strongly deviates from expectations., Comment: Submitted to Physical Review Letters, 8 pages, 3 figures, 2 tables, 7 equations

Published
2023

2. Executive Summary of the Topical Program: Nuclear Isomers in the Era of FRIB

Author

Misch, G. W., Mumpower, M. R., Kondev, F. G., Marley, S. T., Almaraz-Calderon, S., Brodeur, M., Brown, B. A., Carpenter, M. P., Carroll, J. J., Chiara, C. J., Chipps, K. A., Crider, B. P., Gade, A., Grzywacz, R., Jones, K. L., Kay, B. P., Kolos, K., Litvinov, Yu. A., Lopez-Caceres, S., Meyer, B. S., Minamisono, K., Morgan, G. E., Orford, R., Pain, S. D., Purcell, J., Ratkiewicz, A., Schatz, H., Sprouse, T. M., Sun, Y., Surman, R., Tannous, J. A., and Walker, P. M.

Subjects
Nuclear Theory, Nuclear Experiment
Abstract

We report on the Facility for Rare Isotope Beams (FRIB) Theory Alliance topical program "Nuclear Isomers in the Era of FRIB". We outline the many ways isomers influence and contribute to nuclear science and technology, especially in the four FRIB pillars: properties of rare isotopes, nuclear astrophysics, fundamental symmetries, and applications for the nation and society. We conclude with a resolution stating our recommendation that the nuclear physics community actively pursue isomer research. A white paper is forthcoming., Comment: 4 pages including references

Published
2023

3. Reexamination of $^{6}$Li scattering as a Probe to Investigate the Isoscalar Giant Resonances in Nuclei

Author

Zamora, J. C., Sullivan, C., Zegers, R. G. T., Aoi, N., Batail, L., Bazin, D., Carpenter, M., Carroll, J. J., Deloncle, I., Fang, Y. D., Fujita, H., Garg, U., Gey, G., Guess, C. J., Harakeh, M. N., Hoang, T. H., Hudson, E., Ichige, N., Ideguchi, E., Inoue, A., Isaak, J., Iwamoto, C., Kacir, C., Kobayashi, N., Koike, T., Raju, M. Kumar, Lipschutz, S., Liu, M., von Neumann-Cosel, P., Noji, S., Ong, H. J., Péru, S., Pereira, J., Schmitt, J., Tamii, A., Titus, R., Werner, V., Yamamoto, Y., Zhou, X., and Zhu, S.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

Inelastic ${}^{6}$Li scattering at 100 MeV/u on ${}^{12}$C and ${}^{93}$Nb have been measured with the high-resolution magnetic spectrometer Grand Raiden. The magnetic-rigidity settings of the spectrometer covered excitation energies from 10 to 40 MeV and scattering angles in the range $0^\circ < \theta_{\text{lab.}}< 2^\circ$. The isoscalar giant monopole resonance was selectively excited in the present data. Measurements free of instrumental background and the very favorable resonance-to-continuum ratio of ${}^{6}$Li scattering allowed for precise determination of the $E0$ strengths in ${}^{12}$C and ${}^{93}$Nb. It was found that the monopole strength in ${}^{12}$C exhausts $52 \pm 3^\text{(stat.)} \pm 8 ^\text{(sys.)}$\% of the energy-weighted sum rule (EWSR), which is considerably higher than results from previous $\alpha$-scattering experiments. The monopole strength in ${}^{93}$Nb exhausts $92 \pm 4^\text{(stat.)} \pm 10 ^\text{(sys.)}$\% of the EWSR, and it is consistent with measurements of nuclei with mass number of $A\approx90$. Such comparison indicates that the isoscalar giant monopole resonance distributions in these nuclei are very similar, and no influence due to nuclear structure was observed., Comment: 6 Figures

Published
2020
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4. The (Li-6,Li-6*[3.56 MeV]) reaction at 100 MeV/u as a probe of Gamow-Teller transition strengths in the inelastic scattering channel

Author

Sullivan, C., Zegers, R. G. T., Noji, S., Austin, Sam M., Schmitt, J., Aoi, N., Bazin, D., Carpenter, M., Carroll, J. J., Fujita, H., Garg, U., Gey, G., Guess, C. J., Hoang, T. H., Harakeh, M. N., Hudson, E., Ichige, N., Ideguchi, E., Inoue, A., Isaak, J., Iwamoto, C., Kacir, C., Koike, T., Kobayashi, N., Lipschutz, S., Liu, M., von Neumann-Cosel, P., Ong, H. J., Pereira, J., Raju, M. Kumar, Tamii, A., Titus, R., Werner, K., Yamamoto, Y., Fang, Y. D., Zamora, J. C., Zhu, S., Zhou, X., and Research unit Nuclear & Hadron Physics

Subjects
EXCITATIONS, HE-6 REACTION, NUCLEI, Nuclear Theory, R-PROCESS, NEUTRINO SCATTERING, SPIN PROBES, LI-6, Nuclear Experiment, INTERMEDIATE ENERGIES, DECAY, SUPERNOVA
Abstract

Background: Inelastic neutrino-nucleus scattering is important for understanding core-collapse supernovae and the detection of emitted neutrinos from such events in earth-based detectors. Direct measurement of the cross sections is difficult and has only been performed on a few nuclei. It is, therefore, important to develop indirect techniques from which the inelastic neutrino-nucleus scattering cross sections can be determined. Purpose: This paper presents a development of the (Li-6,Li-6*[T = 1, T-z = 0, 0(+), 3.56 MeV]) reaction at 100 MeV/u as a probe for isolating the isovector spin-transfer response in the inelastic channel (Delta S = 1, Delta T = 1, Delta T-z = 0) from which the Gamow-Teller transition strengths from nuclei of relevance for inelastic neutrino-nucleus scattering cross sections can be extracted. Method: By measuring the Li-6 ejectile in a magnetic spectrometer and selecting events in which the 3.56 MeV gamma ray from the decay of the Li-6*[3.56 MeV] state is detected, the isovector spin-transfer selectivity is obtained. High-purity germanium clover detectors served to detect the gamma rays. Doppler reconstruction was used to determine the gamma energy in the rest frame of Li-6. From the Li-6 and 3.56 MeV gamma-momentum vectors the excitation energy of the residual nucleus was determined. Results: In the study of the C-12(Li-6,Li-6*[3.56 MeV]) reaction, the isovector spin-transfer excitation-energy spectrum in the inelastic channel was successfully measured. The strong Gamow-Teller state in C-12 at 15.1 MeV was observed. Comparisons with the analog C-12(Li-6,He-6) reaction validate the method of extracting the Gamow-Teller strength. In measurements of the Mg-24, Nb-93(Li-6,Li-6*[3.56 MeV]) reactions, the 3.56 MeV gamma peak could not be isolated from the strong background in the gamma spectrum from the decay of the isoscalar excitations. It is argued that by using a gamma-ray tracking array instead of a clover array, it is feasible to extend the mass range over which the (Li-6,Li-6*) reaction can be used for extracting the isovector spin-transfer response up to mass numbers of similar to 25 and perhaps higher. Conclusions: It is demonstrated that the (Li-6,Li-6*[3.56 MeV]) reaction probe can be used to isolate the inelastic isovector spin-transfer response in nuclei. Application to nuclei with mass numbers of about 25 or more, however, will require a more efficient gamma-ray array with a better tracking capability.

Published
2018

5. Schottky mass measurements of heavy neutron-rich nuclides in the element range $70\leq Z\leq 79$ at the ESR

Author

Shubina, D., Cakirli, R. B., Litvinov, Yu. A., Blaum, K., Brandau, C., Bosch, F., Carroll, J. J., Casten, R. F., Cullen, D. M., Cullen, I. J., Deo, A. Y., Detwiler, B., Dimopoulou, C., Farinon, F., Geissel, H., Haettner, E., Heil, M., Kempley, R. S., Kozhuharov, C., Kn��bel, R., Kurcewicz, J., Kuzminchuk, N., Litvinov, S. A., Liu, Z., Mao, R., Nociforo, C., Nolden, F., Patyk, Z., Plass, W. R., Prochazka, A., Reed, M. W., Sanjari, M. S., Scheidenberger, C., Steck, M., St��hlker, Th., Sun, B., Swan, T. P. D., Trees, G., Walker, P. M., Weick, H., Winckler, N., Winkler, M., Woods, P. J., Yamaguchi, T., and Zhou, C.

Subjects
Nuclear Theory, FOS: Physical sciences, Nuclear Physics - Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

Storage-ring mass spectrometry was applied to neutron-rich $^{197}$Au projectile fragments. Masses of $^{181,183}$Lu, $^{185,186}$Hf, $^{187,188}$Ta, $^{191}$W, and $^{192,193}$Re nuclei were measured for the first time. The uncertainty of previously known masses of $^{189,190}$W and $^{195}$Os nuclei was improved. Observed irregularities on the smooth two-neutron separation energies for Hf and W isotopes are linked to the collectivity phenomena in the corresponding nuclei., 10 pages, 9 figures, 2 tables

Published
2013

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