Bulletin of the American Physical Society
2012 Fall Meeting of the APS Division of Nuclear Physics
Volume 57, Number 9
Wednesday–Saturday, October 24–27, 2012; Newport Beach, California
Session ND: Nuclear Structure VI |
Hide Abstracts |
Chair: Michael Kovash, University of Kentucky Room: Patio |
Saturday, October 27, 2012 8:30AM - 8:42AM |
ND.00001: Search for isomers in 254Rf J. Chen, F.G. Kondev, D. Seweryniak, M.P. Carpenter, M. Albers, M. Alcorta, P. Bertone, C.J. Chiara, J.P. Greene, C.R. Hoffman, R.V.F. Janssens, T.L. Khoo, T. Lauritsen, C. Nair, A. Rogers, G. Savard, S. Zhu, H. David, D. Doherty, P. Greenlees, J. Konki, S. Stolze, K. Hauschild, D.J. Hartley, S.S. Hota We have searched for predicted two- and four-quasiparticle isomers in $^{254}$Rf using the $^{50}$Ti + $^{206}$Pb heavy-ion fusion-evaporation reaction and the Argonne Fragment Mass Analyzer (FMA). The beam was produced by the ATLAS accelerator with an energy of 242.5 MeV and an intensity of $\sim$200 pnA. The recoiling reaction products were separated by the FMA, identified by their $m/q$ ratio using a Parallel Grid Avalanche Counter detector and implanted into a 160-by-160-strip Double-sided Silicon Strip Detector at the FMA focal plane where correlations between implants and their subsequent decays were established. The results of the experiment will be presented including the observation of spontaneous fission events correlated with mass 254 implants. [Preview Abstract] |
Saturday, October 27, 2012 8:42AM - 8:54AM |
ND.00002: Rare isotope production at the ALTO facility Karolina Kolos The ALTO facility (Acc\'el\'erateur Lin\'eaire et Tandem d'Orsay) at Institut de Physique Nucl\'eaire d'Orsay received its authorization for operating. The aim of this facility is to provide neutron rich isotope beams for both nuclear physics study (far from the valley of stability) and developments dedicated to next generation facilities such as SPIRAL2. The neutron rich isotopes are produced by photo-fission of $^{238}$U induced by the $50$~MeV $10 \mu$A electrons from the linear accelerator. The isotopes coming out from the fission target effuse towards an ion source and are extracted to the on line separator PARRNe. Additional experimental beam line has been constructed and a new detection system BEDO (BEta Decay studies at Orsay) has been mounted and commissioned. The central element of the BEDO is a complex of Compton suppressed germanium detectors and plastic scintillators dedicated to study beta-decay. Gamma rays from the beta decay of $^{84}$Ga isotopes were measured with the prototype of the BEDO system. The gallium atoms were selectively ionized with a newly developed laser ion source. We have improved level schemes of certain descendants of gallium: $^{83,84}$Ge and $^{84}$As. The experimental results will be presented and compared with the shell model calculation. [Preview Abstract] |
Saturday, October 27, 2012 8:54AM - 9:06AM |
ND.00003: Recent Measurements with the NIFFTE Fission TPC Rusty Towell The NIFFTE Time Projection Chamber (TPC) is a powerful tool being developed to take precision measurements of neutron-induced fission cross sections of transuranic elements. These improved data are needed for applications including the development of future generations of nuclear reactors. During the last run at the Los Alamos Neutron Science Center (LANSCE) the partially instrumented TPC took data with several different targets. Results from this run will be shared including an update on the measurement of the cross section ratio for U-238 to U-235. [Preview Abstract] |
Saturday, October 27, 2012 9:06AM - 9:18AM |
ND.00004: Spectroscopy of Neutron-rich $^{248-250}$Cf Nuclei S.S. Hota, P. Chowdhury, A.Y. Deo, C.J. Guess, E.G. Jackson, C.J. Lister, N. D'Olympia, T.L. Khoo, M.P. Carpenter, R.V.F. Janssens, I. Ahmad, J.P. Greene, D. Seweryniak, S. Zhu, P.F. Bertone, G. Henning, C.R. Hoffman, F.G. Kondev, T. Lauritsen, C.K. Nair, C.J. Chiara, S.K. Tandel In continuation of our high-spin studies in neutron-rich $^{244-246}$Pu, $^{246-249}$Cm nuclei, using deep-inelastic and transfer reactions [1], we report on new spectroscopic information in the N = 150-152 nuclei $^{248-250}$Cf. High-spin states in $^{248-250}$Cf nuclei were populated using a $^{208}$Pb beam incident on a radioactive $^{249}$Cf target, with prompt gamma rays detected by the Gammasphere array. The ground state bands of $^{248}$Cf and $^{250}$Cf have been extended to high-spins and the K$^{\pi }$ = 2$^{-}$ octupole band in $^{248}$Cf has been observed for the first time. In addition to the previously observed ground-state bands of $^{249}$Cf [1], a new pair of bands built on a neutron single-particle orbital has been identified. The new data will be presented in the context of the extended systematics of this region and available theoretical predictions for the neutron-rich, transplutonium N $\ge $ 150 nuclei. Possible connections to non-axial octupole collective effects will be discussed. \\[4pt] [1] S. K. Tandel \textit{et al.}, Phys. Rev. C \textbf{82}, 041301(R) (2010) [Preview Abstract] |
Saturday, October 27, 2012 9:18AM - 9:30AM |
ND.00005: Measuring (n,f) cross sections of plutonium nuclei via the surrogate method R.O. Hughes, C.W. Beausang, T.J. Ross, K. Gell, E. Good, T. Tarlow, J.T. Burke, R.J. Casperson, M. McCleskey, A. Saastamoinen, N. Cooper, P. Humby Neutron-induced cross section measurements of exotic nuclei provide a significant experimental challenge due to the need for radioactive targets and high neutron fluxes. Over the past few years the surrogate method has been shown to provide a means of indirectly measuring certain neutron-induced cross sections. Recent results benchmarking (p,t-f) and (p,d-f) reactions as surrogates for (n,f) cross section measurements in uranium nuclei show good agreement with literature data [1]. Building on this work, the use of (p,t-f) and (p,d-f) reactions has very recently been extended to surrogate measurements of the poorly established $^{236}$Pu(n,f) and $^{237}$Pu(n,f) cross sections. The experiment was performed at Texas A\&M University using a 30 MeV proton beam from the K150 cyclotron, incident on $^{239}$Pu and $^{235}$U targets. Charged particle-fission and charged particle-$\gamma$ coincidence data were collected using the combined silicon telescope and $\gamma$-ray array: STARLiTe. Preliminary results will be presented. This work was supported by DoE Grant Numbers: DE-FG52-09 NA29454 and DE-FG02-05 ER41379 (UR) and DE-AC52-07 NA27344 (LLNL).\\[4pt] [1] R.O. Hughes $\emph{et al.}$, PRC $\bf{85}$, 024613 (2012). [Preview Abstract] |
Saturday, October 27, 2012 9:30AM - 9:42AM |
ND.00006: State of the Art Reactor Antineutrino Spectrum Calculations A.A. Sonzogni, T.D. Johnson, E.A. McCutchan Nuclear reactors are copious producers of anti-neutrinos, with fluxes of around 10$^{20 }$ anti-neutrinos/second, a feature which has been exploited by experiments to measured neutrino properties. We have calculated the anti-neutrino spectrum for the neutron induced fission of actinide targets, mainly $^{235}$U, $^{238}$U and $^{239}$Pu. As an input we have used the recently released ENDF/B-VII.1 library, which includes the latest decay data, Q-values and theoretical calculations. The electron spectra from beta minus decay were benchmarked against different measurements. While several hundred fission fragments are produced, it is found that at the energies relevant for the $\bar{\nu} + p \rightarrow n + e^{+}$ reaction, fewer than 50 nuclides contribute more than 70 \% of the flux. Simple estimates of the flux uncertainty and ways to improve our knowledge of the flux will be presented. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700