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Nuclear

University of Richmond

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Full-Text Articles in Physical Sciences and Mathematics

G Factor Of The 2+1 State Of 172Hf, Z. Berant, E. Oster, R. J. Casperson, A. Wolf, V. Werner, A. Heinz, R. F. Casten, G. Gurdal, E. A. Mccutchan, D. S. Brenner, J. R. Terry, R. Winkler, E. Williams, J. Qian, A. Schmidt, M. K. Smith, T. Ahn, C. W. Beausang, P. H. Regan, T. J. Ross, M. Bunce, B. Darakchieva, D. A. Meyer, J. Leblanc, K. Dudziak, C. Bauer, G. Henning Nov 2009

G Factor Of The 2+1 State Of 172Hf, Z. Berant, E. Oster, R. J. Casperson, A. Wolf, V. Werner, A. Heinz, R. F. Casten, G. Gurdal, E. A. Mccutchan, D. S. Brenner, J. R. Terry, R. Winkler, E. Williams, J. Qian, A. Schmidt, M. K. Smith, T. Ahn, C. W. Beausang, P. H. Regan, T. J. Ross, M. Bunce, B. Darakchieva, D. A. Meyer, J. Leblanc, K. Dudziak, C. Bauer, G. Henning

Physics Faculty Publications

The g factor of the 2+1 state of 172Hf was measured using the perturbed angular correlation technique in a static external magnetic field. The result, g(2+1) = 0.25(5), is discussed in relation to the systematics of the previously reported g factors in the Hf isotopes and compared with the predictions of several models. An interesting outcome of the analysis presented in this paper is the agreement between the calculated g factors within the interacting boson approximation (IBA) and the results of a large-scale shell model calculation. This agreement supports the emphasis in the …

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Electroexcitation Of Nucleon Resonances From Clas Data On Single Pion Electroproduction, I. G. Aznauryan, Gerard P. Gilfoyle, Et. Al. Nov 2009

Electroexcitation Of Nucleon Resonances From Clas Data On Single Pion Electroproduction, I. G. Aznauryan, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

We present results on the electroexcitation of the low mass resonances ∆(1232)P33, N(1440)P11, N(1520)D13, and N(1535)S11 in a wide range of Q2. The results were obtained in the comprehensive analysis of data from the Continuous Electron Beam Accelerator Facility (CEBAF) large acceptance spectrometer (CLAS) detector at the Thomas Jefferson National Accelerator Facility (JLab) on differential cross sections, longitudinally polarized beam asymmetries, and longitudinal target and beam-target asymmetries for π electroproduction off the proton. The data were analyzed using two conceptually different approaches—fixed-t dispersion …

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Differential Cross Sections For The Reactions Γp→Pη And Γp→Pη', M. Williams, Gerard P. Gilfoyle, Et. Al. Oct 2009

Differential Cross Sections For The Reactions Γp→Pη And Γp→Pη', M. Williams, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

High-statistics differential cross sections for the reactions γp → pη and γp → pη' have been measured using the CEBAF large acceptance spectrometer (CLAS) at Jefferson Lab for center-of-mass energies from near threshold up to 2.84 GeV. The η' results are the most precise to date and provide the largest energy and angular coverage. The η measurements extend the energy range of the world’s large-angle results by approximately 300 MeV. These new data, in particular the η' measurements, are likely to help constrain the analyses being performed to search for new baryon resonance states.

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Photoproduction Of Π​+Π​- Meson Pairs On The Proton, M. Battaglieri, Gerard P. Gilfoyle, Et. Al. Oct 2009

Photoproduction Of Π​+Π​- Meson Pairs On The Proton, M. Battaglieri, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

The exclusive reaction γp → pπ+π- was studied in the photon energy range 3.0–3.8 GeV and the momentum transfer range 0:4 < -t < 1:0 GeV2. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. In this kinematic range, the integrated luminosity was about 20 pb-1. The reaction was isolated by detecting the π+ and proton in CLAS, and reconstructing the π- via the missing-mass technique. Moments of the di-pion decay angular distributions were derived from the experimental data. Differential cross sections for the S, P, and D …

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Photodisintegration Of 4He Into P + T, R. Nasseripour, Gerard P. Gilfoyle, Et. Al. Oct 2009

Photodisintegration Of 4He Into P + T, R. Nasseripour, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

The two-body photodisintegration of 4He into a proton and a triton has been studied using the CEBAF Large-Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. Real photons produced with the Hall-B bremsstrahlung-tagging system in the energy range from 0.35 to 1.55 GeV were incident on a liquid 4He target. This is the first measurement of the photodisintegration of 4He above 0.4 GeV. The differential cross sections for the γ 4He → pt reaction were measured as a function of photon-beam energy and proton-scattering angle and are compared with the latest model calculations by J.M. …

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Beam Spin Asymmetries In Deeply Virtual Compton Scattering (Dvcs) With Clas At 4.8 Gev, G. Gavalian, Gerard P. Gilfoyle, Et. Al. Sep 2009

Beam Spin Asymmetries In Deeply Virtual Compton Scattering (Dvcs) With Clas At 4.8 Gev, G. Gavalian, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

We report measurements of the beam spin asymmetry in deeply virtual Compton scattering (DVCS) at an electron beam energy of 4.8 GeV using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The DVCS beam spin asymmetry has been measured in a wide range of kinematics, 1.0 < Q2 < 2.8 (GeV/c)2, 0.12 < xB < 0.48, and 0.1 < −t < 0.8 (GeV/c)2, using the reaction ep → e' p X. The number of H(e, e' γ p) and H(e, e'π0p) events are separated in each (Q2, xB, t …

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High-K Multi-Quasiparticle States And Rotational Bands In 255103Lr., H. B. Jeppesen, R. M. Clark, K. E. Gregorich, A. V. Afanasjev, M. N. Ali, J. M. Allmond, C. W. Beausang, M. Cromaz, M. A. Deleplanque, I. Dragojevic, J. Dvorak, P. A. Ellison, P. Fallon, M. A. Garcia, J. M. Gates, S. Gros, I. Y. Lee, A. O. Macchiavelli, S. L. Nelson, H. Nitsche, L. Stavsetra, F. S. Stephens, M. Wiedeking Aug 2009

High-K Multi-Quasiparticle States And Rotational Bands In 255103Lr., H. B. Jeppesen, R. M. Clark, K. E. Gregorich, A. V. Afanasjev, M. N. Ali, J. M. Allmond, C. W. Beausang, M. Cromaz, M. A. Deleplanque, I. Dragojevic, J. Dvorak, P. A. Ellison, P. Fallon, M. A. Garcia, J. M. Gates, S. Gros, I. Y. Lee, A. O. Macchiavelli, S. L. Nelson, H. Nitsche, L. Stavsetra, F. S. Stephens, M. Wiedeking

Physics Faculty Publications

Two isomeric states have been identified in 255Lr. The decay of the isomers populates rotational structures. Comparison with macroscopic-microscopic calculations suggests that the lowest observed sequence is built upon the [624]9/2+ Nilsson state. However, microscopic cranked relativistic Hartree-Bogoliubov (CRHB) calculations do not reproduce the moment of inertia within typical accuracy. This is a clear challenge to theories describing the heaviest elements.

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Π+ Photoproduction On The Proton For Photon Energies From 0.725 To 2.875 Gev, M. Dugger, Gerard P. Gilfoyle, Et. Al. Jun 2009

Π+ Photoproduction On The Proton For Photon Energies From 0.725 To 2.875 Gev, M. Dugger, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

Differential cross sections for the reaction γp → nπ+ have been measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged photon beam with energies from 0.725 to 2.875 GeV. Where available, the results obtained here compare well with previously published results for the reaction. Agreement with the SAID andMAID analyses is found below 1 GeV. The present set of cross sections has been incorporated into the SAID database, and exploratory fits have been made up to 2.7 GeV. Resonance couplings have been extracted and compared to previous determinations. With the addition of these cross sections to the …

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Relative 235U(N,Γ) And (N,F) Cross Sections From 235U(D,Pγ) And (D,Pf), J. M. Allmond, L. A. Bernstein, C. W. Beausang, L. Phair, D. L. Bleuel, J. T. Burke, J. Escher, K. E. Evans, B. L. Goldblum, R. Hatarik, H. B. Jeppesen, S. R. Lesher, M. A. Mcmahan, J. O. Rasmussen, N. D. Scielzo, M. Wiedeking May 2009

Relative 235U(N,Γ) And (N,F) Cross Sections From 235U(D,Pγ) And (D,Pf), J. M. Allmond, L. A. Bernstein, C. W. Beausang, L. Phair, D. L. Bleuel, J. T. Burke, J. Escher, K. E. Evans, B. L. Goldblum, R. Hatarik, H. B. Jeppesen, S. R. Lesher, M. A. Mcmahan, J. O. Rasmussen, N. D. Scielzo, M. Wiedeking

Physics Faculty Publications

The internal surrogate ratio method allows for the determination of an unknown cross section, such as (n,γ), relative to a better-known cross section, such as (n,f), by measuring the relative exit-channel probabilities of a surrogate reaction that proceeds through the same compound nucleus. The validity of the internal surrogate ratio method is tested by comparing the relative γ and fission exit-channel probabilities of a 236U∗ compound nucleus, formed in the 235U(d,p) reaction, to the known 235U(n,γ) and (n,f) cross sections. A model-independent method for measuring the …

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Surrogate Ratio Method In The Actinide Region Using The (Α,Α'F) Reaction, S. R. Lesher, J. T. Burke, L. A. Bernstein, H. Ai, C. W. Beausang, D. L. Bleuel, R. M. Clark, F. S. Dietrich, J. Escher, P. Fallon, J. Gibelin, B. L. Goldblum, I. Y. Lee, A. O. Macchiavelli, M. A. Mcmahan, K. Moody, E. B. Norman, L. Phair, E. Rodriguez-Vieitez, N. D. Scielzo, M. Wiedeking Apr 2009

Surrogate Ratio Method In The Actinide Region Using The (Α,Α'F) Reaction, S. R. Lesher, J. T. Burke, L. A. Bernstein, H. Ai, C. W. Beausang, D. L. Bleuel, R. M. Clark, F. S. Dietrich, J. Escher, P. Fallon, J. Gibelin, B. L. Goldblum, I. Y. Lee, A. O. Macchiavelli, M. A. Mcmahan, K. Moody, E. B. Norman, L. Phair, E. Rodriguez-Vieitez, N. D. Scielzo, M. Wiedeking

Physics Faculty Publications

In the Surrogate Method, the measured decay probability of a compound nucleus formed via a direct reaction is used to extract the cross section for a reaction with a different entrance channel that proceeds through the same compound nucleus. An extension of the Surrogate Method, the Surrogate Ratio Method (SRM), uses a ratio of measured decay probabilities to infer an unknown cross section relative to a known one. To test the SRM we compare the direct-reaction-induced fission probability ratio of 234U(α, α’ f ) to 236U(α, α’f ) with the ratio of cross sections …

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Search For The Photoexcitation Of Exotic Mesons In The Π​+Π​+Π- System, M. Nozar, Gerard P. Gilfoyle, Et. Al. Mar 2009

Search For The Photoexcitation Of Exotic Mesons In The Π​+Π​+Π- System, M. Nozar, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

A search for exotic mesons in the π+π+π- system photoproduced by the charge exchange reaction γp → π+π+π- was carried out by the CLAS Collaboration at Jefferson Lab. A tagged-photon beam with energies in the 4.8 to 5.4 GeV range, produced through bremsstrahlung from a 5.744 GeV electron beam, was incident on a liquid-hydrogen target. A partial wave analysis was performed on a sample of 83 000 events, the highest such statistics to date in this reaction at these energies. The main objective of this study was to look …

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Measurement Of Direct Ƒ0(980) Photoproduction On The Proton, M. Battaglieri, Gerard P. Gilfoyle, Et. Al. Mar 2009

Measurement Of Direct Ƒ0(980) Photoproduction On The Proton, M. Battaglieri, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

We report on the results of the first measurement of exclusive ƒ0(980) meson photoproduction on protons for Eγ = 3.0–3.8 GeV and -t = 0.4–1.0 GeV2. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. The resonance was detected via its decay in the π+ π- channel by performing a partial wave analysis of the reaction γ p → pπ+π-. Clear evidence of the ƒ0(980) meson was found in the interference between P and S waves at Mπ+π …

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Multi-Quasiparticle States In 256Rf, H. B. Jeppesen, I. Dragojevic, R. M. Clark, K. E. Gregorich, M. N. Ali, J. M. Allmond, C. W. Beausang, D. L. Bleuel, M. Cromaz, M. A. Deleplanque, P. A. Ellison, P. Fallon, M. A. Garcia, J. M. Gates, J. P. Greene, S. Gros, I. Y. Lee, H. L. Liu, A. O. Macchiavelli, S. L. Nelson, H. Nitsche, J. R. Pavan, L. Stavsetra, F. S. Stephens, M. Wiedeking, R. Wyss, F. R. Xu Mar 2009

Multi-Quasiparticle States In 256Rf, H. B. Jeppesen, I. Dragojevic, R. M. Clark, K. E. Gregorich, M. N. Ali, J. M. Allmond, C. W. Beausang, D. L. Bleuel, M. Cromaz, M. A. Deleplanque, P. A. Ellison, P. Fallon, M. A. Garcia, J. M. Gates, J. P. Greene, S. Gros, I. Y. Lee, H. L. Liu, A. O. Macchiavelli, S. L. Nelson, H. Nitsche, J. R. Pavan, L. Stavsetra, F. S. Stephens, M. Wiedeking, R. Wyss, F. R. Xu

Physics Faculty Publications

Excited states in 256Rf were populated via the 208Pb(50Ti,2n) fusion–evaporation reaction. Delayed γ-ray and electron decay spectroscopy was performed and three isomeric states in 256Rf have been identified. A fourth low-energy nonyrast state was identified from the γ-ray decay of one of the higher lying isomers. The states are interpreted as multi-quasiparticle excitations.

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Electroproduction Of Pπ+​Π- Off Protons At 0.2 < Q2 < 0.6 Gev2 And 1.3 < W < 1.57 Gev With The Clas Detector, G. V. Fedotov, Gerard P. Gilfoyle, Et. Al. Jan 2009

Electroproduction Of Pπ+​Π- Off Protons At 0.2 < Q2 < 0.6 Gev2 And 1.3 < W < 1.57 Gev With The Clas Detector, G. V. Fedotov, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

This paper reports on the most comprehensive data set obtained on differential and fully integrated cross sections for the process ep → e'pπ+π −. The data were collected with the CLAS detector at Jefferson Laboratory. Measurements were carried out in the as yet unexplored kinematic region of photon virtuality 0.2 < Q2 < 0.6 GeV2 and invariant mass of the final hadron system W from 1.3 to 1.57 GeV. For the first time, nine independent one-fold differential cross sections were determined in each bin of W and Q2 covered by the measurements. A phenomenological analysis of the data …

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Investigation Into The B(E2) Anomaly In 144Nd Using Coulomb Excitation, C. R. Fitzpatrick, V. Werner, R. F. Casten, E. Williams, H. Ai, C. W. Beausang, R. Cakirli, G. Gurdal, A. Heinz, E. A. Mccutchan, D. A. Meyer, E. Novitski, J. Qian, R. Winkler Sep 2008

Investigation Into The B(E2) Anomaly In 144Nd Using Coulomb Excitation, C. R. Fitzpatrick, V. Werner, R. F. Casten, E. Williams, H. Ai, C. W. Beausang, R. Cakirli, G. Gurdal, A. Heinz, E. A. Mccutchan, D. A. Meyer, E. Novitski, J. Qian, R. Winkler

Physics Faculty Publications

The ratio of B(E2) strengths between the lowest lying members of the ground state band in 144Nd, B4/2 = B(E2; 4+1 → 2+1)/B(E2; 2+1 → 0+1), which is used to quantify collectivity in nonmagic nuclei, has been remeasured by means of Coulomb excitation. Ambiguities in literature values for this ratio have been resolved. The results are discussed in terms of the interplay of collective and single-particle degrees of freedom, and in the context of the formation of collective structures in the A = 140 mass region, and more …

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Enhanced Mixing Of Intrinsic States In Deformed Hf Nuclei, E. A. Mccutchan, R. F. Casten, V. Werner, E. Williams, R. Winkler, A. Wolf, Z. Berant, G. Gurdal, J. Qian, H. Ai, L. Amon, C. W. Beausang, D. S. Brenner, R. Cakirli, R. J. Casperson, C. R. Fitzpatrick, D Franks, A. B. Garnsworthy, A. Heinz, R. Luttke, A. F. Mertz, Y. Oktem, N. Pietralla, P. H. Regan, B. Shoraka, J. R. Terry, N. J. Thompson May 2008

Enhanced Mixing Of Intrinsic States In Deformed Hf Nuclei, E. A. Mccutchan, R. F. Casten, V. Werner, E. Williams, R. Winkler, A. Wolf, Z. Berant, G. Gurdal, J. Qian, H. Ai, L. Amon, C. W. Beausang, D. S. Brenner, R. Cakirli, R. J. Casperson, C. R. Fitzpatrick, D Franks, A. B. Garnsworthy, A. Heinz, R. Luttke, A. F. Mertz, Y. Oktem, N. Pietralla, P. H. Regan, B. Shoraka, J. R. Terry, N. J. Thompson

Physics Faculty Publications

Excited low-spin, nonyrast states in 170,172,174Hf were populated in β + /∈decay and studied through off-beam γ-ray spectroscopy. New coincidence data allowed for a substantial revision of the level schemes of Hf170,172 and a confirmation of the level scheme of 174Hf. The Hf isotopes represent a unique situation in which a crossing of collective intrinsic excitations occurs, enhancing significantly the effects of mixing. Using branching ratios from excited 2+ states, this mixing is followed and studied. The resulting mixing matrix elements are found to be ∼30 keV—an …

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Measurement Of Conversion Coefficients In Normal And Triaxial Strongly Deformed Bands In 167Lu, G. Gurdal, C. W. Beausang, D. S. Brenner, H. Ai, R. F. Casten, B. Crider, A. Heinz, E. Williams, D. J. Hartley, M. P. Carpenter, A. A. Hecht, R.V. F. Janssens, T.` Lauritsen, C. J. Lister, R. Raabe, D. Seweryniak, S. Zhu, J. X. Saladin Feb 2008

Measurement Of Conversion Coefficients In Normal And Triaxial Strongly Deformed Bands In 167Lu, G. Gurdal, C. W. Beausang, D. S. Brenner, H. Ai, R. F. Casten, B. Crider, A. Heinz, E. Williams, D. J. Hartley, M. P. Carpenter, A. A. Hecht, R.V. F. Janssens, T.` Lauritsen, C. J. Lister, R. Raabe, D. Seweryniak, S. Zhu, J. X. Saladin

Physics Faculty Publications

Internal conversion coefficients have been measured for transitions in both normal deformed and triaxial strongly deformed bands in 167Lu using the Gammasphere and ICE Ball spectrometers. The results for all in-band transitions are consistent with E2 multipolarity. Upper limits are determined for the internal conversion coefficients for linking transitions between TSD Band 2 and TSD Band 1, the nw = 1 and nw = 0 wobbling bands, respectively.

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G Factor Of The 2+1 State Of 170Hf, A. Wolf, Z. Berant, A. Heinz, V. Werner, E. A. Mccutchan, G. Gurdal, R. Cakirli, Y. Oktem, J. Ai, L. Amon, C. W. Beausang, D. S. Brenner, R. F. Casten, R. J. Casperson, K. Dusling, C. R. Fitzpatrick, A. B. Gransworthy, N. Pietralla, J. Qian, P. H. Regan, N. J. Thompson, E. Williams, R. Winkler Oct 2007

G Factor Of The 2+1 State Of 170Hf, A. Wolf, Z. Berant, A. Heinz, V. Werner, E. A. Mccutchan, G. Gurdal, R. Cakirli, Y. Oktem, J. Ai, L. Amon, C. W. Beausang, D. S. Brenner, R. F. Casten, R. J. Casperson, K. Dusling, C. R. Fitzpatrick, A. B. Gransworthy, N. Pietralla, J. Qian, P. H. Regan, N. J. Thompson, E. Williams, R. Winkler

Physics Faculty Publications

The g factor of the 2+1 state of 170Hf was measured by perturbed γ-γ angular correlation in a static external magnetic field. The result, g(2+1) = 0.28(5), extends the systematics of g factors of even-even Hf isotopes to N = 98 and enables a better test of theoretical models. The g(2+1) experimental values of these isotopes exhibit a remarkable constancy as a function of neutron number. This phenomenon, which was also observed for other isotopic chains in the Gd–W range, is explained in terms of a recently proposed empirical …

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High-Spin States In 191, 193Au And 192Pt: Evidence For Oblate Deformation And Triaxial Shapes, Y. Oktem, D. L. Balabanski, B. Akkus, C. W. Beausang, M. Bostan, R. Cakirli, R. F. Casten, M. Danchev, M. Djongolov, M. N. Erduran, S. Erturk, K. A. Gladniski, G. Gurdal, J. Tm. Goon, D. J. Hartley, A. A. Hecht, R. Krucken, N. Nikolov, J. R. Novak, G. Rainovski, L. L. Riedinger, I. Yigitoglu, N. V. Zamfir, O. Zeidan Oct 2007

High-Spin States In 191, 193Au And 192Pt: Evidence For Oblate Deformation And Triaxial Shapes, Y. Oktem, D. L. Balabanski, B. Akkus, C. W. Beausang, M. Bostan, R. Cakirli, R. F. Casten, M. Danchev, M. Djongolov, M. N. Erduran, S. Erturk, K. A. Gladniski, G. Gurdal, J. Tm. Goon, D. J. Hartley, A. A. Hecht, R. Krucken, N. Nikolov, J. R. Novak, G. Rainovski, L. L. Riedinger, I. Yigitoglu, N. V. Zamfir, O. Zeidan

Physics Faculty Publications

High-spin states of 191, 193Au and 192Pt have been populated in the 186W(11B, xn) and 186W(11B, p4n) reactions, respectively, at a beam energy of 68 MeV and their γ decay was studied using the YRAST Ball detector array at the Wright Nuclear Structure Laboratory at Yale University. The level scheme of 193Au has been extended up to Iπ = 55/2+. New transitions were observed also in 191Au and 192Pt. Particle-plus-Triaxial-Rotor (PTR) and Total Routhian Surface (TRS) calculations were performed to determine the equilibrium deformations of the …

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Absolute And Relative Surrogate Measurements Of The 236U(N,F) Cross Section As A Probe Of Angular Momentum Effects, B. F. Lyles, L. A. Bernstein, J. T. Burke, F. S. Dietrich, J. Escher, I. Thompson, D. L. Bleuel, R. M. Clark, P. Fallon, J. Gibelin, A. O. Macchiavelli, M. A. Mcmahan, L. Phair, E. Rodriguez-Vieitez, M. Wiedeking, C. W. Beausang, S. R. Lesher, B. Darakchieva, M. Evtimova Jul 2007

Absolute And Relative Surrogate Measurements Of The 236U(N,F) Cross Section As A Probe Of Angular Momentum Effects, B. F. Lyles, L. A. Bernstein, J. T. Burke, F. S. Dietrich, J. Escher, I. Thompson, D. L. Bleuel, R. M. Clark, P. Fallon, J. Gibelin, A. O. Macchiavelli, M. A. Mcmahan, L. Phair, E. Rodriguez-Vieitez, M. Wiedeking, C. W. Beausang, S. R. Lesher, B. Darakchieva, M. Evtimova

Physics Faculty Publications

Using both the absolute and relative surrogate techniques, the 236U(n,f) cross section was deduced over an equivalent neutron energy range of 0 to 20 MeV. A 42 MeV 3He beam from the 88 Inch Cyclotron at Lawrence Berkeley National Laboratory was used to perform a (3He,α) pickup reaction on targets of 235U (Jπ=7/2−) and 238U (Jπ = 0+) and the fission decay probabilities were determined. The 235U(3He,αf) and 238U(3He,αf) were surrogates for 233 …

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Spin Dependence Of K Mixing, Strong Configuration Mixing, And Electromagnetic Properties Of 178Hf, A. B. Hayes, D. Cline, C. Y. Wu, H. Ai, H. Amro, C. W. Beausang, R. F. Casten, J. Gerl, A. A. Hecht, A. Heinz, H. Hua, R. O. Hughes, R.V. F. Janssens, C. J. Lister, A. O. Macchiavelli, D. A. Meyer, E. F. Moore, P. Napiorkowski, R. C. Pardo, Ch. Schlegel, D. Seweryniak, M. W. Simon, J. Srebrny, R. Teng, K. Vetter, H. J. Wollersheim Mar 2007

Spin Dependence Of K Mixing, Strong Configuration Mixing, And Electromagnetic Properties Of 178Hf, A. B. Hayes, D. Cline, C. Y. Wu, H. Ai, H. Amro, C. W. Beausang, R. F. Casten, J. Gerl, A. A. Hecht, A. Heinz, H. Hua, R. O. Hughes, R.V. F. Janssens, C. J. Lister, A. O. Macchiavelli, D. A. Meyer, E. F. Moore, P. Napiorkowski, R. C. Pardo, Ch. Schlegel, D. Seweryniak, M. W. Simon, J. Srebrny, R. Teng, K. Vetter, H. J. Wollersheim

Physics Faculty Publications

The combined data of two Coulomb excitation experiments has verified the purely electromagnetic population of the Kπ = 4+, 6+, 8−, and 16+rotational bands in 178Hf via 2≤ν ≤14 K-forbidden transitions, quantifying the breakdown of the K-selection rule with increasing spin in the low-K bands. The γ -, 4+, and 6+bands were extended, and four new states in a rotational band were tentatively assigned to a previously known Kπ = 0+band. The quasiparticle structure of the 6+( …

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Isospin Purity Of T=1 States In The A=38 Nuclei Studied Via Lifetime Measurements In K38, F. M. Prados Estevez, A. M. Bruce, M. J. Taylor, H. Amro, C. W. Beausang, R. F. Casten, J. J. Ressler, C. J. Barton, C. Chandler, G. Hammond Jan 2007

Isospin Purity Of T=1 States In The A=38 Nuclei Studied Via Lifetime Measurements In K38, F. M. Prados Estevez, A. M. Bruce, M. J. Taylor, H. Amro, C. W. Beausang, R. F. Casten, J. J. Ressler, C. J. Barton, C. Chandler, G. Hammond

Physics Faculty Publications

The Doppler Shift Attenuation Method was used to measure lifetimes for levels in 38K at excitation energies of 1698, 2404, 2830, 2996, and 3671 keV, populated using the 40Ca(d, α) 38K reaction at a beam energy of 4.5 MeV. Values of 109(29), 95(22), 457(63), 130(40), and 160(50) fs, respectively, were measured and are compared with previous values obtained using different stopping powers. The matrix element for the transition between the Jπ = 2+ T=1 and 0+ T=1 states in this Tz = 0 nucleus is compared with the analogous transition in the other nuclei in the T = 1 triplet, …

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Revisiting Anomalous B(E2;4+1→2+1)/B(E2;2+1→0+1) Values In 98Ru And 180Pt, E. Williams, C. Plettner, E. A. Mccutchan, H. Levine, N. V. Zamfir, R. Cakirli, R. F. Casten, H. Ai, C. W. Beausang, G. Gurdal, A. Heinz, J. Qian, D. A. Meyer, N. Pietralla, V. Werner Aug 2006

Revisiting Anomalous B(E2;4+1→2+1)/B(E2;2+1→0+1) Values In 98Ru And 180Pt, E. Williams, C. Plettner, E. A. Mccutchan, H. Levine, N. V. Zamfir, R. Cakirli, R. F. Casten, H. Ai, C. W. Beausang, G. Gurdal, A. Heinz, J. Qian, D. A. Meyer, N. Pietralla, V. Werner

Physics Faculty Publications

Recently, a set of nine nonmagic nuclei with anomalous values of the B(E2) ratio B4/2 ≡ B(E2; 4+1 → 2+1)/B(E2; 2+1 → 0+1) were identified. Such values are outside the range allowed by current collective models. In the present work, the B(E2; 4+1 → 2+1) values for two of these nuclei, 98Ru and 180Pt, were re-measured to determine if the current literature values for these nuclei are correct. 98 …

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Collectivity And Configuration Mixing In 186,188Pb And 194Po, T. Grahn, A. Dewald, O. Moller, R. Julin, C. W. Beausang, S. Christen, I. G. Darby, S. Eeckhaudt, P. T. Greenlees, A. Gorgen, K. Helariutta, J. Jolie, P. Jones, S. Juutinen, H. Kettunen, T. Kroll, R. Krucken, Y. Le Coz, M. Leino, A. P. Leppanen, P. Maierbeck, D. A. Meyer, B. Melon, P. Nieminen, M. Nyman, R. D. Page, J. Pakarinen, P. Petkov, P. Rahkila, B. Saha, M. Sandzelius, J. Saren, C. Scholey, J. Uusitalo Aug 2006

Collectivity And Configuration Mixing In 186,188Pb And 194Po, T. Grahn, A. Dewald, O. Moller, R. Julin, C. W. Beausang, S. Christen, I. G. Darby, S. Eeckhaudt, P. T. Greenlees, A. Gorgen, K. Helariutta, J. Jolie, P. Jones, S. Juutinen, H. Kettunen, T. Kroll, R. Krucken, Y. Le Coz, M. Leino, A. P. Leppanen, P. Maierbeck, D. A. Meyer, B. Melon, P. Nieminen, M. Nyman, R. D. Page, J. Pakarinen, P. Petkov, P. Rahkila, B. Saha, M. Sandzelius, J. Saren, C. Scholey, J. Uusitalo

Physics Faculty Publications

Lifetimes of prolate intruder states in 186Pb and oblate intruder states in 194Po have been determined by employing, for the first time, the recoil-decay tagging technique in recoil distance Doppler-shift lifetime measurements. In addition, lifetime measurements of prolate states in 188Pb up to the 8+state were carried out using the recoil-gating method. The B(E2) values have been deduced from which deformation parameters lβ2l = 0.29(5) and lβ2l = 0.17(3) for the prolate and the oblate bands, respectively, have been extracted. The results also shed new light on the …

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Deducing The 237U(N,F) Cross Section Using The Surrogate Ratio Method, J. T. Burke, L. A. Bernstein, J. Escher, L. Ahle, J. A. Church, F. S. Dietrich, K. Moody, E. B. Norman, L. Phair, P. Fallon, R. M. Clark, M. A. Deleplanque, M. Descovich, M. Cromaz, I. Y. Lee, A. O. Macchiavelli, M. A. Mcmahan, E. Rodriguez-Vieitez, F. S. Stephens, H. Ai, C. Plettner, C. W. Beausang, B. Crider May 2006

Deducing The 237U(N,F) Cross Section Using The Surrogate Ratio Method, J. T. Burke, L. A. Bernstein, J. Escher, L. Ahle, J. A. Church, F. S. Dietrich, K. Moody, E. B. Norman, L. Phair, P. Fallon, R. M. Clark, M. A. Deleplanque, M. Descovich, M. Cromaz, I. Y. Lee, A. O. Macchiavelli, M. A. Mcmahan, E. Rodriguez-Vieitez, F. S. Stephens, H. Ai, C. Plettner, C. W. Beausang, B. Crider

Physics Faculty Publications

We have deduced the cross section for 237U(n, f) over an equivalent neutron energy range from 0 to 20 MeV using the surrogate ratio method. A 55 MeV4He beam from the 88 inch cyclotron at Lawrence Berkeley National Laboratory was used to induce fission in the following reactions: 238U(α, αf) and 236U(α, αf). The 238U reaction was a surrogate for 237U(n, f), and the 236U reaction was used as a surrogate for 235U(n, f). Scattered α particles were detected in a fully depleted segmented silicon telescope array …

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First Investigation Of Excited States In The Odd-Proton Nucleus Fr209, D. A. Meyer, C. W. Beausang, J. J. Ressler, H. Ai, H. Amro, M. Babilon, R. F. Casten, C. R. Fitzpatrick, G. Gurdal, A. Heinz, E. A. Mccutchan, C. Plettner, J. Qian, N. J. Thomas, V. Werner, E. Williams, N. V. Zamfir, Jing-Ye Zhang Feb 2006

First Investigation Of Excited States In The Odd-Proton Nucleus Fr209, D. A. Meyer, C. W. Beausang, J. J. Ressler, H. Ai, H. Amro, M. Babilon, R. F. Casten, C. R. Fitzpatrick, G. Gurdal, A. Heinz, E. A. Mccutchan, C. Plettner, J. Qian, N. J. Thomas, V. Werner, E. Williams, N. V. Zamfir, Jing-Ye Zhang

Physics Faculty Publications

Excited states in 209Fr were produced following the 176Yb(37Cl, 4n) reaction. An excitation function was measured with data taken at 173, 179, and 185 MeV. Recoiling fusion-evaporation products were separated using the SASSYER gas-filled spectrometer. HPGe clover detectors of the YRAST Ball array at the target position and at the focal plane were used to detect prompt and delayed gamma ray decays, providing the first spectroscopic information about prompt and delayed transitions in 209Fr. The decay from a proposedπ i13/2 configuration isomer was observed in 209Fr, and its half-life was measured …

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Breakdown Of K Selection In 178Hf, A. B. Hayes, D. Cline, C. Wu, J. Ai, H. Amro, C. W. Beausang, R. F. Casten, J. Gerl, A. A. Hecht, A. Heinz, R. O. Hughes, R.V. F. Janssens, C. J. Lister, A. O. Macchiavelli, D. A. Meyer, E. F. Moore, P. Napiorkowski, R. C. Pardo, Ch. Schlegel, D. Seweryniak, M. W. Simon, J. Srebrny, R. Teng, K. Vetter, H. J. Wollersheim Feb 2006

Breakdown Of K Selection In 178Hf, A. B. Hayes, D. Cline, C. Wu, J. Ai, H. Amro, C. W. Beausang, R. F. Casten, J. Gerl, A. A. Hecht, A. Heinz, R. O. Hughes, R.V. F. Janssens, C. J. Lister, A. O. Macchiavelli, D. A. Meyer, E. F. Moore, P. Napiorkowski, R. C. Pardo, Ch. Schlegel, D. Seweryniak, M. W. Simon, J. Srebrny, R. Teng, K. Vetter, H. J. Wollersheim

Physics Faculty Publications

Coulomb activation of the four quasiparticle Kπ = 16+ 178Hf isomer (t 1/2 = 31 y) has led to the measurement of a set of Eλ matrix elements coupling the isomer band to the ground band. The present data combined with earlier 178Hf Coulomb excitation data have probed the K components in the wave functions and revealed the onset and saturation of K mixing in low-K bands, whereas the mixing is negligible in the high-K bands. The implications can be applied to other quadrupole-deformed nuclei.

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Measuring Reaction Probability Ratios To Simulate Neutron-Induced Cross-Sections Of Short-Lived Nuclei, C. Plettner, H. Ai, C. W. Beausang, L. A. Bernstein, L. Ahle, H. Amro, M. Babilon, J. T. Burke, J. A. Caggiano, R. F. Casten, J. A. Church, J. R. Cooper, B. Crider, G. Gurdal, A. Heinz, E. A. Mccutchan, K. Moody, J. A. Punyon, J. Qian, J. J. Ressler, A. Schiller, E. Williams, W. Younes Sep 2005

Measuring Reaction Probability Ratios To Simulate Neutron-Induced Cross-Sections Of Short-Lived Nuclei, C. Plettner, H. Ai, C. W. Beausang, L. A. Bernstein, L. Ahle, H. Amro, M. Babilon, J. T. Burke, J. A. Caggiano, R. F. Casten, J. A. Church, J. R. Cooper, B. Crider, G. Gurdal, A. Heinz, E. A. Mccutchan, K. Moody, J. A. Punyon, J. Qian, J. J. Ressler, A. Schiller, E. Williams, W. Younes

Physics Faculty Publications

Measuring the neutron-induced fission cross-sections of short-lived nuclei represents an experimental challenge due to target activity and the low intensity of neutron beams. One way to alleviate the problems inherent in the direct measurement is to use the surrogate method, where one measures the decay probability of the same compound nucleus formed using a charged beam and a stable target. The decay probability of the compound nucleus is then used to estimate the neutron-induced cross-section. As an extension to the surrogate method, we introduce a new method of reporting the fission probabilities of two compound nuclei as a ratio, which …

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Quadrupole Moment Measurements Of Tsd1 And Tsd2 Bands In 167Lu, G. Gurdal, H. Amro, C. W. Beausang, D. S. Brenner, M. P. Carpenter, R. F. Casten, C. Engelhardt, G. B. Hagemann, C. R. Hansen, D. J. Hartley, B. Herskind, H. Hubel, T. L. Khoo, T. Lauritsen, W. C. Ma, D. A. Meyer, E. F. Moore, A. Neusser, P. Bringel, D. G. Roux, G. Sletten, R. B. Yadav, Y. Zhang Sep 2005

Quadrupole Moment Measurements Of Tsd1 And Tsd2 Bands In 167Lu, G. Gurdal, H. Amro, C. W. Beausang, D. S. Brenner, M. P. Carpenter, R. F. Casten, C. Engelhardt, G. B. Hagemann, C. R. Hansen, D. J. Hartley, B. Herskind, H. Hubel, T. L. Khoo, T. Lauritsen, W. C. Ma, D. A. Meyer, E. F. Moore, A. Neusser, P. Bringel, D. G. Roux, G. Sletten, R. B. Yadav, Y. Zhang

Physics Faculty Publications

The triaxial strongly deformed (TSD) bands in 167Lu were populated by the 123Sb(48Ca, 4n) reaction with a beam energy of 203 MeV. Gamma rays, requiring fivefold or more in prompt coincidence, were detected with the Gammasphere spectrometer. Of particular interests are TSD bands 1 and 2 which have previously been interpreted as zero phonon and one phonon wobbling bands, respectively. Using the Doppler shift attenuation method (DSAM), a preliminary transition quadrupole moment of 6.9+0.3−0.3 eb was extracted for the TSD1 band. Data analysis continues for TSD2 which is considerably more weakly populated.

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Isomers And Seniority In The Trans-Pb Nuclei, J. J. Ressler, C. W. Beausang, R. F. Casten, N. V. Zamfir, H. Ai, H. Amro, M. Babilon, R. Cakirli, J. A. Caggiano, G. Gurdal, A. Heinz, R. O. Hughes, S. D. Langdown, E. A. Mccutchan, D. A. Meyer, C. Plettner, J. Qian, P. H. Regan, M.J. S. Sciacchitano, N. J. Thomas, E. Williams, A. Yamamoto Sep 2005

Isomers And Seniority In The Trans-Pb Nuclei, J. J. Ressler, C. W. Beausang, R. F. Casten, N. V. Zamfir, H. Ai, H. Amro, M. Babilon, R. Cakirli, J. A. Caggiano, G. Gurdal, A. Heinz, R. O. Hughes, S. D. Langdown, E. A. Mccutchan, D. A. Meyer, C. Plettner, J. Qian, P. H. Regan, M.J. S. Sciacchitano, N. J. Thomas, E. Williams, A. Yamamoto

Physics Faculty Publications

Low-energy excited states of 210Ra and 208Ra were investigated at the Wright Nuclear Structure Laboratory of Yale University. Fusion evaporation recoils were selected using the gas-filled spectrometer, SASSYER. Delayed γ -rays, following isomeric decays, were detected at the focal plane of SASSYER with a small array of HPGe detectors. Transitions following the proposed J π = 8+ isomers were observed, and the half-lives measured. The experiments are discussed and results compared to expectations from the seniority scheme.

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