511 results on '"Reviol, W."'
Search Results
2. α decay of the neutron-deficient isotope At190
- Author
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Andreyev, AN, Seweryniak, D, Andel, B, Antalic, S, Doherty, DT, Korichi, A, Barton, C, Canete, L, Carpenter, MP, Clark, RM, Copp, PA, Cubiss, JG, Heery, J, Hrabar, Y, Huang, H, Huang, T, Karayonchev, V, Kondev, FG, Lauritsen, T, Liu, Z, Lotay, G, Müller-Gatermann, C, Nandi, S, Page, C, Potterveld, DH, Regan, PH, Reviol, W, Rudolph, D, Siciliano, M, Sidhu, RS, Sitarčík, A, Woods, PJ, Yue, Z, and Zhang, W
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Nuclear and Plasma Physics ,Synchrotrons and Accelerators ,Physical Sciences ,Nuclear and plasma physics - Abstract
The α decay of the neutron-deficient At190 isotope was observed following the Rh103(Zr90,3n)At190 reaction at Argonne National Laboratory. The reaction products were separated from the beam using the Argonne Gas-Filled Analyzer and implanted into a double-sided Si strip detector. The spatial and temporal correlations between implanted nuclei and subsequent α decays towards the known daughter isotope Bi186 were used to identify and characterize At190 nuclei. Two possible decay scenarios are proposed for the At190→Bi186 decay.
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- 2023
3. Dissipative reactions with intermediate-energy beams -- a novel approach to populate complex-structure states in rare isotopes
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Gade, A., Brown, B. A., Weisshaar, D., Bazin, D., Brown, K. W., Charity, R. J., Farris, P., Hill, A. M., Li, J., Longfellow, B., Rhodes, D., Reviol, W., and Tostevin, J. A.
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Nuclear Experiment ,Nuclear Theory - Abstract
A novel pathway for the formation of multi-particle-multi-hole (np-mh) excited states in rare isotopes is reported from highly energy- and momentum-dissipative inelastic-scattering events measured in reactions of an intermediate-energy beam of 38Ca on a Be target. The negative-parity,complex-structure final states in 38Ca were observed following the in-beam gamma-ray spectroscopy of events in the 9Be(38Ca,38Ca+gamma)X reaction in which the scattered projectile lost longitudinal momentum of order p = 700 MeV/c. The characteristics of the observed final states are discussed and found to be consistent with the formation of excited states involving the rearrangement of multiple nucleons in a single, highly-energetic projectile-target collision. Unlike the far-less dissipative, surface-grazing reactions usually exploited for the in-beam gamma-ray spectroscopy of rare isotopes, these more energetic collisions appear to offer a practical pathway to nuclear-structure studies of more complex multi-particle configurations in rare isotopes - final states conventionally thought to be out of reach with high-luminosity fast-beam-induced reactions., Comment: Accepted in Phys Rev Lett. arXiv admin note: text overlap with arXiv:2210.01106
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- 2022
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4. Exploiting dissipative reactions to perform in-beam $\gamma$-ray spectroscopy of the neutron-deficient isotopes \nuc{38,39}{Ca}
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Gade, A., Weisshaar, D., Brown, B. A., Bazin, D., Brown, K. W., Charity, R. J., Farris, P., Hill, A. M., Li, J., Longfellow, B., Rhodes, D., Reviol, W., and Tostevin, J. A.
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Nuclear Experiment - Abstract
The neutron-deficient Ca isotopes continue to attract attention due to their importance for testing isospin symmetry and their relevance in capture reactions of interest for nova nucleosynthesis and the shape of light curves in Type I X-ray bursts. To date, spectroscopic information on 38,39 Ca is largely limited to data on lower-spin excited states. Here, we report in-beam {\gamma}-ray spectroscopy of complementary higher-spin, complex-structure states in 39 Ca populated in fast-beam-induced, momentum-dissipative processes leading to neutron pickup onto excited configurations of the projectile, 9 Be(38 Ca , 39 Ca + {\gamma})X. Such a dissipative reaction was recently characterized for the case of inelastic scattering of 38 Ca off 9 Be, 9 Be(38 Ca, 38 Ca + {\gamma})X. Additional data and discussion on the nuclear structure of 38 Ca is also presented. An explanation for the more-complex-structure states, populated with small cross sections in one-nucleon knockout reactions, and observed in the tails of their longitudinal momentum distributions, is also offered., Comment: Submitted to Phys. Rev. C
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- 2022
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5. E2 Rotational Invariants of $0^+_1$ and $2^+_1$ states for $^{106}$Cd: the Emergence of Collective Rotation
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Gray, T. J., Allmond, J. M., Janssens, R. V. F., Korten, W., Stuchbery, A. E., Wood, J. L., Ayangeakaa, A. D., Bottoni, S., Bucher, B. M., Campbell, C. M., Carpenter, M. P., Crawford, H. L., David, H., Doherty, D., Fallon, P., Febbraro, M. T., Galindo-Uribarri, A., Gross, C. J., Komorowska, M., Kondev, F. G., Lauritsen, T., Macchiavelli, A. O., Napiorkowsi, P., Padilla-Rodal, E., Pain, S. D., Reviol, W., Sarantites, D. G., Savard, G., Seweryniak, D., Wu, C. Y., Yu, C. -H., and Zhu, S.
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Nuclear Experiment ,Nuclear Theory - Abstract
The collective structure of $^{106}$Cd is elucidated by multi-step Coulomb excitation of a 3.849 MeV/$A$ beam of $^{106}$Cd on a 1.1 mg/cm$^2$ $^{208}$Pb target using GRETINA-CHICO2 at ATLAS. Fourteen $E2$ matrix elements were obtained. The nucleus $^{106}$Cd is a prime example of emergent collectivity that possesses a simple structure: it is free of complexity caused by shape coexistence and has a small, but collectively active number of valence nucleons. This work follows in a long and currently active quest to answer the fundamental question of the origin of nuclear collectivity and deformation, notably in the cadmium isotopes. The results are discussed in terms of phenomenological models, the shell model, and Kumar-Cline sums of $E2$ matrix elements. The ${\langle 0_2^+ ||E2||2_1^+ \rangle}$ matrix element is determined for the first time, providing a total, converged measure of the electric quadrupole strength, $\langle Q^2 \rangle$, of the first-excited $2_1^+$ level relative to the $0_1^+$ ground state, which does not show an increase as expected of harmonic and anharmonic vibrations. Strong evidence for triaxial shapes in weakly collective nuclei is indicated; collective vibrations are excluded. This is contrary to the only other cadmium result of this kind in $^{114}$Cd by C. Fahlander et al., Nucl. Phys. A485, 327 (1988), which is complicated by low-lying shape coexistence near midshell., Comment: 7 pages, 4 figures
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- 2022
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6. Discovery of the new isotope Lr251: Impact of the hexacontetrapole deformation on single-proton orbital energies near the Z=100 deformed shell gap
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Huang, T, Seweryniak, D, Back, BB, Bender, PC, Carpenter, MP, Chowdhury, P, Clark, RM, Copp, PA, He, X-T, Herzberg, RD, Hoff, DEM, Jayatissa, H, Khoo, TL, Kondev, FG, Morgan, G, Morse, C, Korichi, A, Lauritsen, T, Müller-Gatermann, C, Potterveld, DH, Reviol, W, Rogers, AM, Saha, S, Savard, G, Sharma, K, Stolze, S, Waniganeththi, S, Wilson, GL, Wu, J, Xu, Y-F, and Zhu, S
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Nuclear and Plasma Physics ,Synchrotrons and Accelerators ,Physical Sciences ,Nuclear and plasma physics - Abstract
The products of the Tl203,205(Ti50,2n) fusion-evaporation reactions were studied using the recently commissioned Argonne Gas-Filled Analyzer at Argonne National Laboratory. Two α-decay activities with energies of 9210(19) and 9246(19) keV and half-lives of 42-14+42 and 24.4-4.5+7.0 ms were observed which were followed by the known α decays of Md247 and Es243. They are interpreted as originating from the 1/2-[521] and 7/2-[514] single-proton Nilsson states in the hitherto unknown isotope Lr251. From the measured Qα values the 1/2- level was placed 117(27) keV above the 7/2- level in Lr251 in contrast to Lr255 where the 1/2- level is the lowest. Also, the α decay of Lr253 was studied in more detail and a new α line at 8660(20) keV was found and a new half-life value of 2.46(32) s for an isomeric state in Lr253 was measured. The Lr251,253,255Qα values were compared with predictions of various mass models. The relative energies of the 1/2-[521] and 7/2-[514] single-proton Nilsson states in Lr251,253,255 isotopes were compared with results of the cranking shell model with pairing treated using the particle-number-conserving method. The level separation and, in particular, the level order change between Lr251 and Lr255 was reproduced only when the hexacontetrapole deformation 6 was included in the calculations.
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- 2022
7. The LSU-Argonne conversion electron spectrometer: A new detector for the X-Array and SATURN decay station
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Lopez-Caceres, S., Marley, S.T., Carpenter, M.P., Savard, G., Kondev, F.G., Copp, P., Reviol, W., Müller-Gatermann, C., Seweryniak, D., Clark, J.A., Santiago-Gonzalez, D., Morgan, G.E., Mitchell, A.J., Wilson, G.L., and Smith, M.L.
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- 2024
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8. Experimental and shell-model study of excited states in Fe292655 and related notes on Cu262955
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Rudolph, D, Andreoiu, C, Bentley, MA, Carpenter, MP, Charity, RJ, Clark, RM, Ekman, J, Fahlander, C, Fallon, P, Reviol, W, Sarantites, DG, and Seweryniak, D
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Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Nuclear & Particles Physics - Abstract
The fusion-evaporation reaction at 125-MeV beam energy was used to populate excited states in . Combining the Gammasphere spectrometer with ancillary devices including the Microball CsI(Tl) array and a shell of neutron detectors, a comprehensive level scheme could be derived. The experimental results are compared with theoretical results from shell-model calculations. Taking into account isospin-symmetry breaking terms is found to considerably improve the shell-model description for . This motivated a predictive case study of near-yrast states in the mirror nucleus .
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- 2021
9. In-beam $\gamma$-ray spectroscopy at the proton dripline: $^{40}$Sc
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Gade, A., Weisshaar, D., Brown, B. A., Tostevin, J. A., Bazin, D., Brown, K., Charity, R. J., Farris, P. J., Hill, A. M., Li, J., Longfellow, B., Reviol, W., and Rhodes, D.
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Nuclear Experiment - Abstract
We report on the first in-beam $\gamma$-ray spectroscopy of the proton-dripline nucleus $^{40}$Sc using two-nucleon pickup onto an intermediate-energy rare-isotope beam of $^{38}$Ca. The $^{9}$Be($^{38}$Ca,$^{40}$Sc$+\gamma$)X reaction at 60.9 MeV/nucleon mid-target energy selectively populates states in $^{40}$Sc for which the transferred proton and neutron couple to high orbital angular momentum. In turn, due to angular-momentum selection rules in proton emission and the nuclear structure and energetics of $^{39}$Ca, such states in $^{40}$Sc then exhibit $\gamma$-decay branches although they are well above the proton separation energy. This work uniquely complements results from particle spectroscopy following charge-exchange reactions on $^{40}$Ca as well as $^{40}$Ti EC/$\beta^+$ decay which both display very different selectivities. The population and $\gamma$-ray decay of the previously known first $(5^-)$ state at 892 keV and the observation of a new level at 2744 keV are discussed in comparison to the mirror nucleus and shell-model calculations. On the experimental side, this work shows that high-resolution in-beam $\gamma$-ray spectroscopy is possible with new generation Ge arrays for reactions induced by rare-isotope beams on the level of a few $\mu$b of cross section., Comment: Accepted for publication in Phys. Lett. B
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- 2020
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10. Invariant-mass spectroscopy of $^{14}$O excited states
- Author
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Charity, R. J., Brown, K. W., Okolowicz, J., Ploszajczak, M., Elson, J. E., Reviol, W., Sobotka, L. G., Buhro, W. W., Chajecki, Z., Lynch, W. G., Manfredi, J., Shane, R., Showalter, R. H., Tsang, M. B., Weisshaar, D., Winkelbauer, J. R., Bedoor, S., and Wuosmaa, A. H.
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Nuclear Experiment ,Nuclear Theory - Abstract
Excited states in $^{14}$O have been investigated both experimentally and theoretically. Experimentally, these states were produced via neutron-knockout reactions with a fast $^{15}$O beam and the invariant-mass technique was employed to isolate the 1$p$ and 2$p$ decay channels and determine their branching ratios. The spectrum of excited states was also calculated with the Shell Model Embedded in the Continuum that treats bound and scattering states in a unified model. By comparing energies, widths and decay branching patterns, spin and parity assignments for all experimentally observed levels below 8 MeV are made. This includes the location of the second 2$^{+}$ state that we find is in near degeneracy with the third 0$^{+}$ state. An interesting case of sequential 2$p$ decay through a pair of degenerate $^{13}$N excited states with opposite parities was found where the interference between the two sequential decay pathways produces an unusual relative-angle distribution between the emitted protons., Comment: 19 pages, 20 figures
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- 2019
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11. The rate of the astrophysical 48Cr(p,γ)49Mn reaction and its influence on the potential A = 48 waiting point in the rp process
- Author
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O'Shea, C., primary, Lotay, G., additional, Doherty, D.T., additional, Seweryniak, D., additional, Lau, R., additional, Bartram, G., additional, Byrne, S., additional, Canete, L., additional, Carpenter, M.P., additional, Chipps, K.A., additional, Copp, P.A., additional, Cousins, C., additional, Henderson, J., additional, Huang, T., additional, Jayatissa, H., additional, Kondev, F., additional, Müller-Gatermann, C., additional, Pain, S.D., additional, Paxman, C., additional, Reed, B.J., additional, Reviol, W., additional, Rogers, A.M., additional, Russell, R., additional, Schatz, H., additional, and Siciliano, M., additional
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- 2024
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12. Single-particle and collective excitations in the N=28 isotones Fe54 and Mn53
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Rudolph, D, Ragnarsson, I, Andreoiu, C, Bentley, MA, Carpenter, MP, Charity, RJ, Clark, RM, Ekman, J, Fahlander, C, Fallon, P, Reviol, W, Sarantites, DG, and Seweryniak, D
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Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Nuclear & Particles Physics - Abstract
The fusion-evaporation reaction S32+Si28 at 125 MeV beam energy was used to populate high-spin states in the semimagic N=28 nuclei Mn53 and Fe54. With a combination of the Gammasphere spectrometer and ancillary devices including the Microball CsI(Tl) array, extensive high-spin level schemes are derived. They exhibit rotational-like collective structures and competing single-particle excitations. The experimental results are compared with predictions from shell-model calculations, for which the inclusion of isopin-symmetry-breaking terms is found to improve the description. An interpretation of the high-spin states is put forward using cranked Nilsson-Strutinsky calculations, indicative of contributions from collective excitations beyond some 8-MeV excitation energy and highlighting the importance of the g9/2 intruder orbital in this energy range.
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- 2020
13. Single-particle and collective excitations in the N=28 isotones Fe 54 and Mn 53
- Author
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Rudolph, D, Ragnarsson, I, Andreoiu, C, Bentley, MA, Carpenter, MP, Charity, RJ, Clark, RM, Ekman, J, Fahlander, C, Fallon, P, Reviol, W, Sarantites, DG, and Seweryniak, D
- Abstract
The fusion-evaporation reaction S32+Si28 at 125 MeV beam energy was used to populate high-spin states in the semimagic N=28 nuclei Mn53 and Fe54. With a combination of the Gammasphere spectrometer and ancillary devices including the Microball CsI(Tl) array, extensive high-spin level schemes are derived. They exhibit rotational-like collective structures and competing single-particle excitations. The experimental results are compared with predictions from shell-model calculations, for which the inclusion of isopin-symmetry-breaking terms is found to improve the description. An interpretation of the high-spin states is put forward using cranked Nilsson-Strutinsky calculations, indicative of contributions from collective excitations beyond some 8-MeV excitation energy and highlighting the importance of the g9/2 intruder orbital in this energy range.
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- 2020
14. Invariant-mass spectroscopy of $^{18}$Ne, $^{16}$O, and $^{10}$C excited states formed in neutron transfer reactions
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Charity, R. J., Brown, K. W., Elson, J. M., Reviol, W., Sobotka, L. G., Buhro, W. W., Chajecki, Z., Lynch, W. G., Manfredi, J., Shane, R., Showalter, R. H., Tsang, M. B., Weisshaar, D., Winkelbauer, J., Bedoor, S., McNeel, D. G., and Wuosmaa, A. H.
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Nuclear Experiment - Abstract
Neutron transfer reactions with fast secondary beams of $^{17}$Ne, $^{15}$O, and $^9$C have been studied with the HiRA and CAESAR arrays. Excited states of $^{18}$Ne, $^{16}$O, and $^{10}$C in the continuum have been identified using invariant-mass spectroscopy. The best experimental resolution of these states is achieved by selecting events where the decay fragments are emitted transverse to the beam direction. We have confirmed a number of spin assignments made in previous works for the negative-parity states of $^{18}$Ne. In addition we have found new higher-lying excited states in $^{16}$O and $^{18}$Ne, some of which fission into two ground-state $^8$Be fragments. Finally for $^{10}$C, a new excited state was observed. These transfer reactions were found to leave the remnant of the $^9$Be target nuclei at very high excitation energies and maybe associated with the pickup of a deeply-bound $^9$Be neutron., Comment: 21 pages, 18 figures
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- 2018
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15. Understanding the Low-Energy Enhancement of the $\gamma$-ray Strength Function of $^{56}$Fe
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Jones, M. D., Macchiavelli, A. O., Wiedeking, M., Bernstein, L. A., Crawford, H. L., Campbell, C. M., Clark, R. M., Cromaz, M., Fallon, P., Lee, I. Y., Salathe, M., Wiens, A., Ayangeakaa, A. D., Bleuel, D. L., Bottoni, S., Carpenter, M. P., Davids, H. M., Elson, J., Görgen, A., Guttormsen, M., Janssens, R. V. F., Kinnison, J. E., Kirsch, L., Larsen, A. C., Lauritsen, T., Reviol, W., Sarantites, D. G., Siem, S., Voinov, A. V., and Zhu, S.
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Nuclear Experiment - Abstract
A model-independent technique was used to determine the $\gamma$-ray Strength Function ($\gamma$SF) of $^{56}$Fe down to $\gamma$-ray energies less than 1 MeV for the first time with GRETINA using the $(p,p')$ reaction at 16 MeV. No difference was observed in the energy dependence of the $\gamma$SF built on $2^{+}$ and $4^{+}$ final states, supporting the Brink hypothesis. In addition, angular distribution and polarization measurements were performed. The angular distributions are consistent with dipole radiation. The polarization results show a small bias towards magnetic character in the region of the enhancement.
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- 2018
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16. Intruder configurations of excited states in the neutron-rich isotopes P 33 and P 34
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Lubna, RS, Tripathi, V, Tabor, SL, Tai, PL, Kravvaris, K, Bender, PC, Volya, A, Bouhelal, M, Chiara, CJ, Carpenter, MP, Janssens, RVF, Lauritsen, T, McCutchan, EA, Zhu, S, Clark, RM, Fallon, P, MacChiavelli, AO, Paschalis, S, Petri, M, Reviol, W, and Sarantites, DG
- Abstract
Excited states in the neutron-rich isotopes P33 and P34 were populated by the O18+O18 fusion-evaporation reaction at Elab=24 MeV. The Gammasphere array was used along with the Microball particle detector array to detect γ transitions in coincidence with the charged particles emitted from the compound nucleus S36. The use of Microball enabled the selection of the proton emission channel. It also helped in determining the exact position and energy of the emitted proton; this was later employed in kinematic Doppler corrections. 16 new transitions and 13 new states were observed in P33 and 21 γ rays and 20 energy levels were observed in P34 for the first time. The nearly 4π geometry of Gammasphere allowed the measurement of γ-ray angular distributions leading to spin assignments for many states. The experimental observations for both isotopes were interpreted with the help of shell-model calculations using the (0+1)ω PSDPF interaction. The calculations accounted for both the 0p-0h and 1p-1h states reasonably well and indicated that 2p-2h excitations might dominate the higher-spin configurations in both P33 and P34.
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- 2018
17. Intruder configurations of excited states in the neutron-rich isotopes P33 and P34
- Author
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Lubna, RS, Tripathi, Vandana, Tabor, SL, Tai, P-L, Kravvaris, K, Bender, PC, Volya, A, Bouhelal, M, Chiara, CJ, Carpenter, MP, Janssens, RVF, Lauritsen, T, McCutchan, EA, Zhu, S, Clark, RM, Fallon, P, Macchiavelli, AO, Paschalis, S, Petri, M, Reviol, W, and Sarantites, DG
- Subjects
Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Nuclear & Particles Physics - Abstract
Excited states in the neutron-rich isotopes P33 and P34 were populated by the O18+O18 fusion-evaporation reaction at Elab=24 MeV. The Gammasphere array was used along with the Microball particle detector array to detect γ transitions in coincidence with the charged particles emitted from the compound nucleus S36. The use of Microball enabled the selection of the proton emission channel. It also helped in determining the exact position and energy of the emitted proton; this was later employed in kinematic Doppler corrections. 16 new transitions and 13 new states were observed in P33 and 21 γ rays and 20 energy levels were observed in P34 for the first time. The nearly 4π geometry of Gammasphere allowed the measurement of γ-ray angular distributions leading to spin assignments for many states. The experimental observations for both isotopes were interpreted with the help of shell-model calculations using the (0+1)ω PSDPF interaction. The calculations accounted for both the 0p-0h and 1p-1h states reasonably well and indicated that 2p-2h excitations might dominate the higher-spin configurations in both P33 and P34.
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- 2018
18. Examination of the low-energy enhancement of the γ -ray strength function of Fe 56
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Jones, MD, MacChiavelli, AO, Wiedeking, M, Bernstein, LA, Crawford, HL, Campbell, CM, Clark, RM, Cromaz, M, Fallon, P, Lee, IY, Salathe, M, Wiens, A, Ayangeakaa, AD, Bleuel, DL, Bottoni, S, Carpenter, MP, Davids, HM, Elson, J, Görgen, A, Guttormsen, M, Janssens, RVF, Kinnison, JE, Kirsch, L, Larsen, AC, Lauritsen, T, Reviol, W, Sarantites, DG, Siem, S, Voinov, AV, and Zhu, S
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nucl-ex - Abstract
A model-independent technique was used to determine the γ-ray strength function (γSF) of Fe56 down to γ-ray energies less than 1 MeV for the first time with GRETINA using the (p,p′) reaction at 16 MeV. No difference was observed in the energy dependence of the γSF built on 2+ and 4+ final states, supporting the Brink hypothesis. In addition, angular distribution and polarization measurements were performed. The angular distributions are consistent with dipole radiation. The polarization results show a small bias towards magnetic character in the region of the enhancement.
- Published
- 2018
19. Investigation of the \(\gamma \)-ray Properties of the \(2^+\) States in \(^{14}\)C
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Corbari, G., primary, Bottoni, S., additional, Ciemała, M., additional, Crespi, F.C.L., additional, Fornal, B., additional, Leoni, S., additional, Janssens, R.V.F., additional, Pain, S.D., additional, Siciliano, M., additional, Albanese, E., additional, Ayangeakaa, A.D., additional, Benzoni, G., additional, Carmichael, S., additional, Carpenter, M., additional, Chipps, K., additional, Cieplicka-Oryńczak, N., additional, Cizewski, A., additional, Copp, P., additional, Febbraro, M., additional, Forson, J., additional, Gamba, E., additional, Garland, H., additional, Gilardy, G., additional, Hooker, J., additional, Iskra, Ł.W., additional, Jayatissa, H., additional, Kondev, F., additional, Jones, K., additional, Jones, M.D., additional, Lauritsen, T., additional, Li, J., additional, Little, D., additional, Million, B., additional, Müller-Gatermann, C., additional, Palmisano, A., additional, Polettini, M., additional, Porzio, C., additional, Ratkiewicz, A., additional, Reviol, W., additional, Sensharma, N., additional, Seweryniak, D., additional, Sims, H., additional, Stolz, S., additional, Toomey, R., additional, Ummel, C., additional, Wieland, O., additional, Wilson, G., additional, Wu, J., additional, Zhu, S., additional, and Ziliani, S., additional
- Published
- 2024
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20. Results of the ASY-EOS experiment at GSI: The symmetry energy at suprasaturation density
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Russotto, P., Gannon, S., Kupny, S., Lasko, P., Acosta, L., Adamczyk, M., Al-Ajlan, A., Al-Garawi, M., Al-Homaidhi, S., Amorini, F., Auditore, L., Aumann, T., Ayyad, Y., Basrak, Z., Benlliure, J., Boisjoli, M., Boretzky, K., Brzychczyk, J., Budzanowski, A., Caesar, C., Cardella, G., Cammarata, P., Chajecki, Z., Chartier, M., Chbihi, A., Colonna, M., Cozma, M. D., Czech, B., De Filippo, E., Di Toro, M., Famiano, M., Gašparić, I., Grassi, L., Guazzoni, C., Guazzoni, P., Heil, M., Heilborn, L., Introzzi, R., Isobe, T., Kezzar, K., Kiš, M., Krasznahorkay, A., Kurz, N., La Guidara, E., Lanzalone, G., Fèvre, A. Le, Leifels, Y., Lemmon, R. C., Li, Q. F., Lombardo, I., Lukasik, J., Lynch, W. G., Marini, P., Matthews, Z., May, L., Minniti, T., Mostazo, M., Pagano, A., Pagano, E. V., Papa, M., Pawlowski, P., Pirrone, S., Politi, G., Porto, F., Reviol, W., Riccio, F., Rizzo, F., Rosato, E., Rossi, D., Santoro, S., Sarantites, D. G., Simon, H., Skwirczynska, I., Sosin, Z., Stuhl, L., Trautmann, W., Trifirò, A., Trimarchi, M., Tsang, M. B., Verde, G., Veselsky, M., Vigilante, M., Wang, Yongjia, Wieloch, A., Wigg, P., Winkelbauer, J., Wolter, H. H., Wu, P., Yennello, S., Zambon, P., Zetta, L., and Zoric, M.
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Nuclear Experiment - Abstract
Directed and elliptic flows of neutrons and light charged particles were measured for the reaction 197Au+197Au at 400 MeV/nucleon incident energy within the ASY-EOS experimental campaign at the GSI laboratory. The detection system consisted of the Large Area Neutron Detector LAND, combined with parts of the CHIMERA multidetector, of the ALADIN Time-of-flight Wall, and of the Washington-University Microball detector. The latter three arrays were used for the event characterization and reaction-plane reconstruction. In addition, an array of triple telescopes, KRATTA, was used for complementary measurements of the isotopic composition and flows of light charged particles. From the comparison of the elliptic flow ratio of neutrons with respect to charged particles with UrQMD predictions, a value \gamma = 0.72 \pm 0.19 is obtained for the power-law coefficient describing the density dependence of the potential part in the parametrization of the symmetry energy. It represents a new and more stringent constraint for the regime of supra-saturation density and confirms, with a considerably smaller uncertainty, the moderately soft to linear density dependence deduced from the earlier FOPI-LAND data. The densities probed are shown to reach beyond twice saturation., Comment: 25 pages, 22 figures, accepted for publication in Physical Review C
- Published
- 2016
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21. Cross-shell excitations in Si 31
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Tai, PL, Tabor, SL, Lubna, RS, Kravvaris, K, Bender, PC, Tripathi, V, Volya, A, Carpenter, MP, Janssens, RVF, Lauritsen, T, McCutchan, EA, Zhu, S, Clark, RM, Fallon, P, Paschalis, S, Petri, M, Macchiavelli, AO, Reviol, W, and Sarantites, DG
- Subjects
1.1 Normal biological development and functioning - Abstract
The Si31 nucleus was produced through the O18(O18, αn) fusion-evaporation reaction at Elab=24MeV. Evaporated α particles from the reaction were detected and identified in the Microball detector array for channel selection. Multiple γ-ray coincidence events were detected in Gammasphere. The energy and angle information for the α particles was used to determine the Si31 recoil kinematics on an event-by-event basis for a more accurate Doppler correction. A total of 22 new states and 52 new γ transitions were observed, including 14 from states above the neutron separation energy. The positive-parity states predicted by the shell-model calculations in the sd model space agree well with experiment. The negative-parity states were compared with shell-model calculations in the psdpf model space with some variations in the N=20 shell gap. The best agreement was found with a shell gap intermediate between that originally used for A≈20 nuclei and that previously adapted for P32,34. This variation suggests the need for a more universal cross-shell interaction.
- Published
- 2017
22. Triaxiality near the 110Ru ground state from Coulomb excitation
- Author
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Doherty, DT, Allmond, JM, Janssens, RVF, Korten, W, Zhu, S, Zielińska, M, Radford, DC, Ayangeakaa, AD, Bucher, B, Batchelder, JC, Beausang, CW, Campbell, C, Carpenter, MP, Cline, D, Crawford, HL, David, HM, Delaroche, JP, Dickerson, C, Fallon, P, Galindo-Uribarri, A, Kondev, FG, Harker, JL, Hayes, AB, Hendricks, M, Humby, P, Girod, M, Gross, CJ, Klintefjord, M, Kolos, K, Lane, GJ, Lauritsen, T, Libert, J, Macchiavelli, AO, Napiorkowski, PJ, Padilla-Rodal, E, Pardo, RC, Reviol, W, Sarantites, DG, Savard, G, Seweryniak, D, Srebrny, J, Varner, R, Vondrasek, R, Wiens, A, Wilson, E, Wood, JL, and Wu, CY
- Subjects
Nuclear & Particles Physics ,Mathematical Physics ,Astronomical and Space Sciences ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics - Abstract
A multi-step Coulomb excitation measurement with the GRETINA and CHICO2 detector arrays was carried out with a 430-MeV beam of the neutron-rich 110Ru (t1/2=12 s) isotope produced at the CARIBU facility. This represents the first successful measurement following the post-acceleration of an unstable isotope of a refractory element. The reduced transition probabilities obtained for levels near the ground state provide strong evidence for a triaxial shape; a conclusion confirmed by comparisons with the results of beyond-mean-field and triaxial rotor model calculations.
- Published
- 2017
23. Probing proton cross-shell excitations through the two-neutron removal from Ca38
- Author
-
Beck, T., primary, Gade, A., additional, Brown, B. A., additional, Tostevin, J. A., additional, Weisshaar, D., additional, Bazin, D., additional, Brown, K. W., additional, Charity, R. J., additional, Farris, P. J., additional, Gillespie, S. A., additional, Hill, A. M., additional, Li, J., additional, Longfellow, B., additional, Reviol, W., additional, and Rhodes, D., additional
- Published
- 2023
- Full Text
- View/download PDF
24. The observation of long-range three-body Coloumb effects in the decay of 16Ne
- Author
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Brown, K. W, Charity, R. J., Sobotka, L. G., Chajecki, Z., Grigorenko, L. V., Egorova, I. A., Parfenova, Yu. L., Zhukov, M. V., Bedoor, S., Buhro, W. W., Elson, J. M., Lynch, W. G., Manfredi, J., McNeel, D. G., Reviol, W., Shane, R., Showalter, R. H., Tsang, M. B., Winkelbauer, J. R., and Wuosmaa, A. H.
- Subjects
Nuclear Experiment ,Nuclear Theory - Abstract
The interaction of an $E/A$=57.6-MeV $^{17}$Ne beam with a Be target was used to populate levels in $^{16}$Ne following neutron knockout reactions. The decay of $^{16}$Ne states into the three-body $^{14}$O+$p$+$p$ continuum was observed in the High Resolution Array (HiRA). For the first time for a 2p emitter, correlations between the momenta of the three decay products were measured with sufficient resolution and statistics to allow for an unambiguous demonstration of their dependence on the long-range nature of the Coulomb interaction. Contrary to previous experiments, the intrinsic decay width of the $^{16}$Ne ground state was found to be narrow ($\Gamma<60$~keV), consistent with theoretical estimates., Comment: 6 pages, 5 figures
- Published
- 2014
- Full Text
- View/download PDF
25. High-spin transition quadrupole moments in neutron-rich Mo and Ru nuclei: testing $\gamma $ softness?
- Author
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Snyder, J. B., Reviol, W., Sarantites, D. G., Afanasjev, A. V., Janssens, R. V. F., Abusara, H., Carpenter, M. P., Chen, X., Chiara, C. J., Greene, J. P., Lauritsen, T., McCutchan, E. A., Seweryniak, D., and Zhu, S.
- Subjects
Nuclear Experiment - Abstract
The transition quadrupole moments, $Q_{t}$, of rotational bands in the neutron-rich, even-mass $^{102-108}$Mo and $^{108-112}$Ru nuclei were measured in the 8 to 16 $\hbar $ spin range with the Doppler-shift attenuation method. The nuclei were populated as fission fragments from $^{252}$Cf fission. The detector setup consisted of the Gammasphere spectrometer and the HERCULES fast-plastic array. At moderate spin, the $Q_{t}$ moments are found to be reduced with respect to the values near the ground states. Attempts to describe the observations in mean-field-based models, specifically cranked relativistic Hartree-Bogoliubov theory, illustrate the challenge theory faces and the difficulty to infer information on $\gamma $ softness and triaxiality from the data., Comment: 17 pages, 4 figures
- Published
- 2013
- Full Text
- View/download PDF
26. Lifetime Measurements in $^{182,186}$Pt}
- Author
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Walpe, J. C., Garg, U., Naguleswaran, S., Wei, J., Reviol, W., Ahmad, I., Carpenter, M. P., and Khoo, T. L.
- Subjects
Nuclear Experiment ,Nuclear Theory - Abstract
Lifetimes in the yrast bands of the nuclei $^{182,186}$Pt have been measured using the Doppler-shift Recoil Distance technique. The results in both cases {\em viz.} a sharp increase in B(E2) values at very low spins, may be interpreted as resulting from a mixing between two bands of different quadrupole deformations., Comment: 12 pages; 4 figures; submitted to PRC
- Published
- 2012
- Full Text
- View/download PDF
27. Evidence for Shape Co-existence at medium spin in 76Rb
- Author
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Wadsworth, R., Ragnarsson, I., Carlsson, B. G., Ma, Hai-Liang, Davies, P. J., Andreoiu, C., Austin, R. A. E., Carpenter, M. P., Dashdorj, D., Freeman, S. J., Garrett, P. E., Greene, J., Görgen, A., Jenkins, D. G., Johnston-Theasby, F., Joshi, P., Macchiavelli, A. O., Moore, F., Mukherjee, G., Reviol, W., Sarantites, D. G., Seweryniak, D., Svensson, C. E., and Valiente-Dobón, J. J.
- Subjects
Nuclear Experiment ,Nuclear Theory - Abstract
Four previously known rotational bands in 76Rb have been extended to moderate spins using the Gammasphere and Microball gamma ray and charged particle detector arrays and the 40Ca(40Ca,3pn) reaction at a beam energy of 165 MeV. The properties of two of the negative-parity bands can only readily be interpreted in terms of the highly successful Cranked Nilsson-Strutinsky model calculations if they have the same configuration in terms of the number of g9/2 particles, but they result from different nuclear shapes (one near-oblate and the other near-prolate). These data appear to constitute a unique example of shape co-existing structures at medium spins., Comment: Accepted for publication in Physics Letters B
- Published
- 2011
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- View/download PDF
28. Confirmation of a new resonance in Si26 and contribution of classical novae to the galactic abundance of Al26
- Author
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Canete, L., primary, Doherty, D. T., additional, Lotay, G., additional, Seweryniak, D., additional, Campbell, C. M., additional, Carpenter, M. P., additional, Catford, W. N., additional, Chipps, K. A., additional, Henderson, J., additional, Izzard, R. G., additional, Janssens, R. V. F., additional, Jayatissa, H., additional, José, J., additional, Kennington, A. R. L., additional, Kondev, F. G., additional, Korichi, A., additional, Lauritsen, T., additional, Müller-Gatermann, C., additional, Paxman, C., additional, Podolyák, Zs., additional, Reed, B. J., additional, Regan, P. H., additional, Reviol, W., additional, Siciliano, M., additional, Wilson, G. L., additional, Yates, R., additional, and Zhu, S., additional
- Published
- 2023
- Full Text
- View/download PDF
29. 100th Anniversary of the Compton Effect: Its Discovery and Present-Day Impact on Nuclear Physics
- Author
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Reviol, W., primary and Avila, M. L., additional
- Published
- 2023
- Full Text
- View/download PDF
30. First observation of a shape isomer and a low-lying strongly-coupled prolate band in neutron-deficient semi-magic Pb
- Author
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Zhang, W.Q., Andreyev, A.N., Liu, Z., Seweryniak, D., Huang, H., Li, Z.H., Li, J.G., Guo, C.Y., Doherty, D.T., Barzakh, A.E., Van Duppen, P., Cubiss, J.G., Andel, B., Antalic, S., Block, M., Bronis, A., Carpenter, M.P., Copp, P., Ding, B., Favier, Z., Giacoppo, F., Huang, T.H., Yu, X.H., Kindler, B., Kondev, F.G., Lauritsen, T., Li, G.S., Lommel, B., Lu, H.Y., Al Monthery, M., Mošať, P., Niu, Y.F., Raison, C., Reviol, W., Savard, G., Stolze, S., Wilson, G.L., Wu, H.Y., Wang, Z.H., Xu, F.R., Zeng, Q.B., and Zhou, X.H.
- Abstract
Prompt and delayed γ-ray spectroscopy of the neutron-deficient, semi-magic isotope $^{187}$Pb has been performed using the recoil-decay and isomer-decay tagging techniques at the Argonne Gas-Filled Analyzer. A new 5.15(15)-μs isomeric state at only 308 keV above the spherical 3/2$^{−}$ ground state is identified and classified as a shape isomer. A strongly-coupled band is observed on top of the isomer, which is nearly identical to the one built on the prolate 7/2$^{−}$[514] Nilsson state in the isotone $^{185}$Hg. Based on this similarity and on the result of the potential-energy surface calculations, the new isomer in $^{187}$Pb is proposed to originate from the same configuration. The retarded character of the 308-keV (7/2$^{−}$)→3/2gs− transition with a deduced B(E2)=5.6(2)×10−4 W.u. can be well explained by the significant difference between the prolate parent and spherical daughter configurations, leading to the shape isomerism. The excitation energy of the isomer is surprisingly low, being roughly half of the excitation energies of the known 0$^{+}$ intruder bandheads in the neighboring $^{186,188}$Pb isotopes. The combined results of the present work and the previous α-decay and laser spectroscopy studies present evidence for triple shape coexistence at low energy in the negative-parity configurations of $^{187}$Pb, which is well reproduced by the potential-energy surface calculations.
- Published
- 2023
31. Lifetime Measurements in 120Xe
- Author
-
Walpe, J. C., Davis, B. F., Naguleswaran, S., Reviol, W., Garg, U., Pan, Xing-Wang, Feng, Da Hsuan, and Saladin, J. X.
- Subjects
Nuclear Experiment ,Nuclear Theory - Abstract
Lifetimes for the lowest three transitions in the nucleus $^{120}$Xe have been measured using the Recoil Distance Technique. Our data indicate that the lifetime for the $2_{1}^{+} \to 0_{1}^{+}$ transition is more than a factor of two lower than the previously adopted value and is in keeping with more recent measurements performed on this nucleus. The theoretical implications of this discrepancy and the possible reason for the erroneous earlier results are discussed. All measured lifetimes in $^{120}$Xe, as well as the systematics of the lifetimes of the 2$_{1}^{+}$ states in Xe isotopes, are compared with predictions of various models. The available data are best described by the Fermion Dynamic Symmetry Model (FDSM)., Comment: 9 pages, RevTeX, 3 figures with Postscript file available on request at Umesh.Garg.1@nd.edu, pan@einstein.physics.drexel.edu. Submitted to Phys. Rev. C
- Published
- 1995
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- View/download PDF
32. Lifetimes of high-spin states in Kr-76
- Author
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Valiente-Dobon, JJ, Svensson, CE, O'Leary, CD, Ragnarsson, I, Andreoiu, C, Austin, RAE, Carpenter, MP, Dashdorj, D, Finlay, P, Freeman, SJ, Garrett, PE, Gorgen, A, Greene, J, Grinyer, GF, Hyland, B, Jenkins, D, Johnston-Theasby, F, Joshi, P, Kelsall, NS, Macchiavelli, AO, Moore, F, Mukherjee, G, Phillips, AA, Reviol, W, Sarantites, D, Schumaker, MA, Seweryniak, D, Smith, MB, Wadsworth, R, and Ward, D
- Subjects
Nuclear & Particles Physics ,Mathematical Sciences ,Physical Sciences - Published
- 2005
33. Lifetimes of high-spin states in 76Kr
- Author
-
Valiente-Dobón, JJ, Svensson, CE, O'Leary, CD, Ragnarsson, I, Andreoiu, C, Austin, RAE, Carpenter, MP, Dashdorj, D, Finlay, P, Freeman, SJ, Garrett, PE, Görgen, A, Greene, J, Grinyer, GF, Hyland, B, Jenkins, D, Johnston-Theasby, F, Joshi, P, Kelsall, NS, Macchiavelli, AO, Moore, F, Mukherjee, G, Phillips, AA, Reviol, W, Sarantites, D, Schumaker, MA, Seweryniak, D, Smith, MB, Wadsworth, R, and Ward, D
- Subjects
Mathematical Sciences ,Physical Sciences ,Nuclear & Particles Physics ,Mathematical sciences ,Physical sciences - Published
- 2005
34. Measurement of the B(E2↑) strengths of Ca36 and Ca38
- Author
-
Dronchi, N., primary, Weisshaar, D., additional, Brown, B. A., additional, Gade, A., additional, Charity, R. J., additional, Sobotka, L. G., additional, Brown, K. W., additional, Reviol, W., additional, Bazin, D., additional, Farris, P. J., additional, Hill, A. M., additional, Li, J., additional, Longfellow, B., additional, Rhodes, D., additional, Paneru, S. N., additional, Gillespie, S. A., additional, Anthony, A., additional, Rubino, E., additional, and Biswas, S., additional
- Published
- 2023
- Full Text
- View/download PDF
35. \(\gamma \) Decay from the Near-neutron-threshold \(2^{+}\) State in \(^{14}\)C: A Probe of Collectivization Phenomena in Light Nuclei
- Author
-
Corbari, G., primary, Bottoni, S., additional, Ciemala, M., additional, Crespi, F.C.L., additional, Leoni, S., additional, Fornal, B., additional, Janssens, R.V.F., additional, Pain, S.D., additional, Siciliano, M., additional, Albanese, E., additional, Ayangeakaa, A.D., additional, Benzoni, G., additional, Carmichael, S., additional, Carpenter, M., additional, Chipps, K., additional, Cieplicka, N., additional, Copp, P., additional, Forson, J., additional, Gamba, E., additional, Iskra, L.W., additional, Jayatissa, H., additional, Kondev, F., additional, Lauritsen, T., additional, Million, B., additional, Müller-Gatermann, C., additional, Palmisano, A., additional, Polettini, M., additional, Porzio, C., additional, Reviol, W., additional, Sensharma, N., additional, Seweryniak, D., additional, Ummel, C., additional, Wieland, O., additional, Wilson, G., additional, Zhu, S., additional, and Ziliani, S., additional
- Published
- 2023
- Full Text
- View/download PDF
36. “Phoswich Wall”: A charged-particle detector array for inverse-kinematic reactions with the Gretina/GRETA γ-ray arrays
- Author
-
Sarantites, D.G., Reviol, W., Elson, J.M., Kinnison, J.E., Izzo, C.J., Manfredi, J., Liu, J., Jung, H.S., and Goerres, J.
- Published
- 2015
- Full Text
- View/download PDF
37. Decay spectroscopy of the blocked fission product I130
- Author
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Mattera, A., primary, McCutchan, E. A., additional, Zhu, S., additional, Morse, C., additional, Carpenter, M. P., additional, Copp, P., additional, Müller-Gatermann, C., additional, Reviol, W., additional, Greene, J. P., additional, and Gott, M., additional
- Published
- 2022
- Full Text
- View/download PDF
38. Dissipative Reactions with Intermediate-Energy Beams: A Novel Approach to Populate Complex-Structure States in Rare Isotopes
- Author
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Gade, A., primary, Brown, B. A., additional, Weisshaar, D., additional, Bazin, D., additional, Brown, K. W., additional, Charity, R. J., additional, Farris, P., additional, Hill, A. M., additional, Li, J., additional, Longfellow, B., additional, Rhodes, D., additional, Reviol, W., additional, and Tostevin, J. A., additional
- Published
- 2022
- Full Text
- View/download PDF
39. Exploiting dissipative reactions to perform in-beam γ -ray spectroscopy of the neutron-deficient isotopes Ca38,39
- Author
-
Gade, A., primary, Weisshaar, D., additional, Brown, B. A., additional, Bazin, D., additional, Brown, K. W., additional, Charity, R. J., additional, Farris, P., additional, Hill, A. M., additional, Li, J., additional, Longfellow, B., additional, Rhodes, D., additional, Reviol, W., additional, and Tostevin, J. A., additional
- Published
- 2022
- Full Text
- View/download PDF
40. E2 rotational invariants of 01+ and 21+ states for 106Cd: The emergence of collective rotation
- Author
-
Gray, T.J., primary, Allmond, J.M., additional, Janssens, R.V.F., additional, Korten, W., additional, Stuchbery, A.E., additional, Wood, J.L., additional, Ayangeakaa, A.D., additional, Bottoni, S., additional, Bucher, B.M., additional, Campbell, C.M., additional, Carpenter, M.P., additional, Crawford, H.L., additional, David, H., additional, Doherty, D.T., additional, Fallon, P., additional, Febbraro, M.T., additional, Galindo-Uribarri, A., additional, Gross, C.J., additional, Komorowska, M., additional, Kondev, F.G., additional, Lauritsen, T., additional, Macchiavelli, A.O., additional, Napiorkowsi, P., additional, Padilla-Rodal, E., additional, Pain, S.D., additional, Reviol, W., additional, Sarantites, D.G., additional, Savard, G., additional, Seweryniak, D., additional, Wu, C.Y., additional, Yu, C.-H., additional, and Zhu, S., additional
- Published
- 2022
- Full Text
- View/download PDF
41. First observation of the decay of the 13/2+ isomer in 183Hg and B(M2) systematics of neutron transitions across the nuclear chart
- Author
-
Huang, H., primary, Zhang, W.Q., additional, Andreyev, A.N., additional, Liu, Z., additional, Seweryniak, D., additional, Li, Z.H., additional, Guo, C.Y., additional, Barzakh, A.E., additional, Van Duppen, P., additional, Andel, B., additional, Antalic, S., additional, Block, M., additional, Bronis, A., additional, Carpenter, M.P., additional, Copp, P., additional, Cubiss, J.G., additional, Ding, B., additional, Doherty, D.T., additional, Favier, Z., additional, Giacoppo, F., additional, Huang, T.H., additional, Kindler, B., additional, Kondev, F.G., additional, Lauritsen, T., additional, Li, J.G., additional, Li, G.S., additional, Lommel, B., additional, Lu, H.Y., additional, Al Monthery, M., additional, Mošať, P., additional, Niu, Y.F., additional, Raison, C., additional, Reviol, W., additional, Savard, G., additional, Stolze, S., additional, Wilson, G.L., additional, Wu, H.Y., additional, Wang, Z.H., additional, Xu, F.R., additional, Zeng, Q.B., additional, Yu, X.H., additional, Zeng, F.F., additional, and Zhou, X.H., additional
- Published
- 2022
- Full Text
- View/download PDF
42. E2 rotational invariants of And States for Cd: The emergence of collective rotation
- Author
-
Gray, T.J., Allmond, J.M., Janssens, R.V.F., Korten, W., Stuchbery, A.E., Wood, J.L., Ayangeakaa, A.D., Bottoni, S., Bucher, B.M., Campbell, C.M., Carpenter, M.P., Crawford, H.L., David, H., Doherty, D.T., Fallon, P., Febbraro, M.T., Galindo-Uribarri, A., Gross, C.J., Komorowska, M., Kondev, F.G., Lauritsen, T., Macchiavelli, A.O., Napiorkowsi, P., Padilla-Rodal, E., Pain, S.D., Reviol, W., Sarantites, D.G., Savard, G., Seweryniak, D., Wu, C.Y., Yu, C.H., and Zhu, S.
- Abstract
The collective structure of $^{106}$Cd is elucidated by multi-step Coulomb excitation of a 3.849 MeV/A beam of $^{106}$Cd on a 1.1 mg/cm$^{2}$ $^{208}$Pb target using GRETINA-CHICO2 at ATLAS. Fourteen E2 matrix elements were obtained. The nucleus $^{106}$Cd is a prime example of emergent collectivity that possesses a simple structure: it is free of complexity caused by shape coexistence and has a small, but collectively active number of valence nucleons. This work follows in a long and currently active quest to answer the fundamental question of the origin of nuclear collectivity and deformation, notably in the cadmium isotopes. The results are discussed in terms of phenomenological models, the shell model, and Kumar-Cline sums of E2 matrix elements. The 〈02+||E2||21+〉 matrix element is determined for the first time, providing a total, converged measure of the electric quadrupole strength, 〈Q2〉, of the first-excited 21+ level relative to the 01+ ground state, which does not show an increase as expected of harmonic and anharmonic vibrations. Strong evidence for triaxial shapes in weakly collective nuclei is indicated; collective vibrations are excluded. This is contrary to the only other cadmium result of this kind in $^{114}$Cd by C. Fahlander et al. (1988) [38], which is complicated by low-lying shape coexistence near midshell.
- Published
- 2022
43. Identification of excited states in 188Bi and 188Po
- Author
-
Zhang, W. Q., Andreyev, A. N., Liu, Z., Seweryniak, D., Huang, H., Li, Z. H., Li, J. G., Guo, C. Y., Barzakh, A. E., Van Duppen, P., Al Monthery, M., Andel, B., Antalic, S., Block, M., Bronis, A., Carpenter, M. P., Copp, P., Cubiss, J. G., Ding, B., Doherty, D. T., Favier, Z., Giacoppo, F., Huang, T. H., Kindler, B., Kondev, F. G., Lauritsen, T., Li, G. S., Lommel, B., Lu, H. Y., Moifmmode selse šaifmmode telse ť, P., Niu, Y. F., Raison, C., Reviol, W., Savard, G., Stolze, S., Wilson, G. L., Wu, H. Y., Wang, Z. H., Xu, F. R., Yu, X. H., Zeng, Q. B., and Zhou, X. H.
- Published
- 2022
44. First observation of the decay of the 13/2 Isomer in Hg and ( 2) Systematics of Neutron Transitions Across the Nuclear Chart
- Author
-
Huang, H., Zhang, W.Q., Andreyev, A.N., Liu, Z., Seweryniak, D., Li, Z.H., Guo, C.Y., Barzakh, A.E., Van Duppen, P., Andel, B., Antalic, S., Block, M., Bronis, A., Carpenter, M.P., Copp, P., Cubiss, J.G., Ding, B., Doherty, D.T., Favier, Z., Giacoppo, F., Huang, T.H., Kindler, B., Kondev, F.G., Lauritsen, T., Li, J.G., Li, G.S., Lommel, B., Lu, H.Y., Al Monthery, M., Mošať, P., Niu, Y.F., Raison, C., Reviol, W., Savard, G., Stolze, S., Wilson, G.L., Wu, H.Y., Wang, Z.H., Xu, F.R., Zeng, Q.B., Yu, X.H., Zeng, F.F., and Zhou, X.H.
- Abstract
The decay of the 13/2$^{+}$ isomeric state in $^{183}$Hg was observed for the first time following the α decay of the 13/2$^{+}$ isomer in $^{187}$Pb produced in the $^{142}$Nd($^{50}$Cr, 2p3n) reaction. Using α−γ delayed coincidence measurements, the half-life of this isomer was measured to be 290(30) μs. This isomer is proposed to deexcite by an unobserved low-energy M2 transition to the known 9/2$^{−}$ member of a strongly prolate-deformed 7/2$^{−}$[514] band, followed by a 105-keV M1 transition to the bandhead. A lower limit of B(M2) ≥ 0.018 W.u. was deduced for the unobserved transition. The presumed retardation is proposed to be due to the notable shape change between the initial, nearly spherical, and the final, strongly deformed, states. A similar scenario is also considered for the 13/2$^{+}$ isomer in $^{181}$Hg, suggesting both are cases of shape isomers. The B(M2) systematics of neutron transitions across the nuclear chart is discussed.
- Published
- 2022
45. Identification of excited states in Bi188 and Po188
- Author
-
Zhang, W. Q., primary, Andreyev, A. N., additional, Liu, Z., additional, Seweryniak, D., additional, Huang, H., additional, Li, Z. H., additional, Li, J. G., additional, Guo, C. Y., additional, Barzakh, A. E., additional, Van Duppen, P., additional, Al Monthery, M., additional, Andel, B., additional, Antalic, S., additional, Block, M., additional, Bronis, A., additional, Carpenter, M. P., additional, Copp, P., additional, Cubiss, J. G., additional, Ding, B., additional, Doherty, D. T., additional, Favier, Z., additional, Giacoppo, F., additional, Huang, T. H., additional, Kindler, B., additional, Kondev, F. G., additional, Lauritsen, T., additional, Li, G. S., additional, Lommel, B., additional, Lu, H. Y., additional, Mošať, P., additional, Niu, Y. F., additional, Raison, C., additional, Reviol, W., additional, Savard, G., additional, Stolze, S., additional, Wilson, G. L., additional, Wu, H. Y., additional, Wang, Z. H., additional, Xu, F. R., additional, Yu, X. H., additional, Zeng, Q. B., additional, and Zhou, X. H., additional
- Published
- 2022
- Full Text
- View/download PDF
46. Masses and Beta-decay Studies of Neutron-rich Nuclei using the X-array and Gammasphere
- Author
-
Kondev F.G., Hartley D.J., Orford R., Clark J.A, Savard G., Auranen K., Ayangeakaa A.D., Bottoni S., Carpenter M.P., Copp P., Hicks K., Hoffman C.R., Janssens R.V.F., Kay B.P., Lauritsen T., Li T., Marley S.T., Morgan G.E., Mukherjee G., Nandi S., Reviol W., Sethi J., Seweryniak D., Stolze S., Wu J., Yadav R., and Zhu S.
- Subjects
Physics ,QC1-999 - Abstract
Properties of neutron-rich nuclei in the A˜160 region are important for achieving a better understanding of the nuclear structure in this region where little is known owing to diffculties in the production of these nuclei at the present nuclear physics facilities. These properties are essential ingredients in the interpretation of the rareearth peak at A˜160 in the r process abundance distribution, since theoretical models are sensitive to nuclear structure input. Predicated on these ideas, we have initiated a new experimental program at Argonne National Laboratory. During the first experiment, beams from the Californium Rare Isotope Breeder Upgrade radioactive beam facility were used in conjunction with the SATURN decay station and the X-array. We focused initially on several odd-odd nuclei, where β decays of both the ground state and an excited isomer were investigated. Because of the spin difference, a variety of structures in the daughter nuclei were selectively populated and characterized based on their decay properties. Mass measurements using the Canadian Penning Trap aimed at establishing the excitation energy of the β-decaying isomers were also carried out. Evidence was found for a change in the single-particle structure, which in turn results in the formation of a sizable N=98 sub-shell gap at large deformation. Results from the first experimental campaign using the newly-commissioned β-decay station at Gammasphere are also presented.
- Published
- 2019
- Full Text
- View/download PDF
47. First observation of a shape isomer and a low-lying strongly-coupled prolate band in neutron-deficient semi-magic 187Pb
- Author
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Zhang, W.Q., primary, Andreyev, A.N., additional, Liu, Z., additional, Seweryniak, D., additional, Huang, H., additional, Li, Z.H., additional, Li, J.G., additional, Guo, C.Y., additional, Doherty, D.T., additional, Barzakh, A.E., additional, Van Duppen, P., additional, Cubiss, J.G., additional, Andel, B., additional, Antalic, S., additional, Block, M., additional, Bronis, A., additional, Carpenter, M.P., additional, Copp, P., additional, Ding, B., additional, Favier, Z., additional, Giacoppo, F., additional, Huang, T.H., additional, Yu, X.H., additional, Kindler, B., additional, Kondev, F.G., additional, Lauritsen, T., additional, Li, G.S., additional, Lommel, B., additional, Lu, H.Y., additional, Al Monthery, M., additional, Mošať, P., additional, Niu, Y.F., additional, Raison, C., additional, Reviol, W., additional, Savard, G., additional, Stolze, S., additional, Wilson, G.L., additional, Wu, H.Y., additional, Wang, Z.H., additional, Xu, F.R., additional, Zeng, Q.B., additional, and Zhou, X.H., additional
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- 2022
- Full Text
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48. In-beam studies of very neutron-deficient heavy nuclei
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Julin, R., Greenlees, P. T., Helariutta, K., Jones, P., Juutinen, S., Leppänen, A.-P., Kankaanpää, H., Keenan, A., Kettunen, H., Kuusiniemi, P., Leino, M., Muikku, M., Nieminen, P., Pakarinen, J., Rahkila, P., Uusitalo, J., Joss, D. T., Williams, S. J., Jenkins, D. G., Kelsall, N.-S., Wadsworth, R., Hauschild, K., Hürstel, A., Korten, W., Le Coz, Y., Andreyev, A. N., Van Duppen, P., Huyse, M., Van de Vel, K., Moore, C. J., O’Leary, C. D., Page, R. D., Taylor, M. J., Reviol, W., Smith, M. B., Äystö, Juha, editor, Dendooven, Peter, editor, Jokinen, Ari, editor, and Leino, Matti, editor
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- 2003
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49. E2 rotational invariants of <math altimg='si1.svg'><msubsup><mrow><mn>0</mn></mrow><mrow><mn>1</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msubsup></math> and <math altimg='si2.svg'><msubsup><mrow><mn>2</mn></mrow><mrow><mn>1</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msubsup></math> states for 106Cd: The emergence of collective rotation
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Gray, T.J., Allmond, J.M., Janssens, R.V.F., Korten, W., Stuchbery, A.E., Wood, J.L., Ayangeakaa, A.D., Bottoni, S., Bucher, B.M., Campbell, C.M., Carpenter, M.P., Crawford, H.L., David, H., Doherty, D.T., Fallon, P., Febbraro, M.T., Galindo-Uribarri, A., Gross, C.J., Komorowska, M., Kondev, F.G., Lauritsen, T., Macchiavelli, A.O., Napiorkowsi, P., Padilla-Rodal, E., Pain, S.D., Reviol, W., Sarantites, D.G., Savard, G., Seweryniak, D., Wu, C.Y., Yu, C.-H., Zhu, S., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay
- Subjects
Electromagnetic moments ,Shell model ,[PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th] ,Coulomb excitation ,Sum rules ,[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,Collective model - Abstract
International audience; The collective structure of 106Cd is elucidated by multi-step Coulomb excitation of a 3.849 MeV/A beam of 106Cd on a 1.1 mg/cm2208Pb target using GRETINA-CHICO2 at ATLAS. Fourteen E2 matrix elements were obtained. The nucleus 106Cd is a prime example of emergent collectivity that possesses a simple structure: it is free of complexity caused by shape coexistence and has a small, but collectively active number of valence nucleons. This work follows in a long and currently active quest to answer the fundamental question of the origin of nuclear collectivity and deformation, notably in the cadmium isotopes. The results are discussed in terms of phenomenological models, the shell model, and Kumar-Cline sums of E2 matrix elements. The 〈02+||E2||21+〉 matrix element is determined for the first time, providing a total, converged measure of the electric quadrupole strength, 〈Q2〉, of the first-excited 21+ level relative to the 01+ ground state, which does not show an increase as expected of harmonic and anharmonic vibrations. Strong evidence for triaxial shapes in weakly collective nuclei is indicated; collective vibrations are excluded. This is contrary to the only other cadmium result of this kind in 114Cd by C. Fahlander et al. (1988) [38], which is complicated by low-lying shape coexistence near midshell.
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- 2022
50. Identification of excited states in $^{188}\mathrm{Bi}$ and $^{188}\mathrm{Po}$
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Zhang, W.Q., Andreyev, A.N., Liu, Z., Seweryniak, D., Huang, H., Li, Z.H., Li, J.G., Guo, C.Y., Barzakh, A.E., van Duppen, P., Al Monthery, M., Andel, B., Antalic, S., Block, M., Bronis, A., Carpenter, M.P., Copp, P., Cubiss, J.G., Ding, B., Doherty, D.T., Favier, Z., Giacoppo, F., Huang, T.H., Kindler, B., Kondev, F.G., Lauritsen, T., Li, G.S., Lommel, B., Lu, H.Y., Mošať, P., Niu, Y.F., Raison, C., Reviol, W., Savard, G., Stolze, S., Wilson, G.L., Wu, H.Y., Wang, Z.H., Xu, F.R., Yu, X.H., Zeng, Q.B., Zhou, X.H., Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay
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[PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th] - Abstract
International audience; The neutron-deficient Bi188 and Po188 isotopes have been studied by γ-ray spectroscopy using the recoil-decay tagging technique with the Argonne Gas-Filled Analyzer. A new 0.25(5)-μs isomeric state and a prompt cascade formed by 319-, 366-, and 462-keV γ rays have been established on top of the (10−) α-decaying isomer in Bi188. The first excited (2+) state in Po188 was identified, its excitation energy of 242(2) keV continues the nearly constant trend for the first 2+ states in Po190,192,194. The state is most likely a member of a prolate rotational band built on the ground state, albeit mixing with other coexisting configurations cannot be excluded. The new results obtained in the present work provide new information to shape coexistence in bismuth and polonium isotopes near the neutron midshell at N=104. In this mass region, a reduction in the prompt γ-ray yield obtained with recoil decay tagging was observed for a few nuclides, and the possible reasons are presented.
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- 2022
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