Bulletin of the American Physical Society
2007 Annual Meeting of the Division of Nuclear Physics
Volume 52, Number 10
Wednesday–Saturday, October 10–13, 2007; Newport News, Virginia
Session BH: Applications of Nuclear Physics |
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Chair: Geoffrey Greene, Oak Ridge National Laboratory Room: Newport News Marriott at City Center Blue Point I |
Thursday, October 11, 2007 2:00PM - 2:12PM |
BH.00001: Nuclear Physics on Critical Path for Space Missions Ram Tripathi Protection from hazards of space radiation has been identified as one of the five NASA's critical areas for human space flights. The space radiation environment consists of galactic cosmic rays (GCR), solar particle events (SPE), trapped radiation, and includes ions of all the known elements over a very broad energy range. These ions penetrate spacecraft materials producing nuclear fragments and secondary particles that damage biological tissues, microelectronic devices, and materials. One of the major considerations in human exploration and development of space is protecting astronauts, habitat and electronics against the hazards of severe deep space radiation. Accurate risk assessments critically depend on the accuracy of the input information about the interaction of ions with materials, electronics and tissues. Due to paucity of the huge amount of needed experimental input data about the interaction of radiation, it is imperative to develop reliable accurate models of nuclear reactions and structures that form the basic input ingredients. State-of-the-art nuclear cross sections models have been developed at the NASA Langley Research center. The vital role and importance of nuclear physics for space missions would be discussed. [Preview Abstract] |
Thursday, October 11, 2007 2:12PM - 2:24PM |
BH.00002: Can we use the equivalent sphere model to approximate organ doses in space radiation environments? Zi-Wei Lin For space radiation protection it is often useful to calculate dose or dose equivalent in blood forming organs (BFO). It has been customary to use a 5cm equivalent sphere to approximate the BFO dose. However, many previous studies have concluded that a 5cm sphere gives very different dose values from the exact BFO values. A study by Bier, Townsend and Maxson (Adv. Space Res. 21, 1998) concludes that a 9cm sphere is a reasonable approximation for BFO doses in solar particle event environments. In this study we use a deterministic radiation transport to investigate the reason behind these observations and to extend earlier studies. We take different space radiation environments, including solar particle events and galactic cosmic rays at different solar modulation, and calculate the dose and dose equivalent in the skin, eye and BFO using their thickness distribution functions from the Computerized Anatomical Man model. We then determine in which cases and at what radius parameters the equivalent sphere model is a reasonable approximation. [Preview Abstract] |
Thursday, October 11, 2007 2:24PM - 2:36PM |
BH.00003: Preliminary tests of a high performance LaBr$_{3}$ gamma imager for small animals . Jianguo Qian, Eric Bradley, Stan Majewski, John Mckisson, Vladimir Popov, James Proffitt, Margaret Saha, Jonathan Sutton, Andrew Weisenberger, Robert Welsh, Amir Yazdi A novel medical gamma ray imager comprised of an array of four Hamamatsu H9500 position sensitive photomultiplier tubes (PSPMT) coupled directly to a single slab of LaBr$_{3}$ scintillator has been designed and tested. The phototube-scintillator array, fabricated by Bicron-St. Gobain Inc (France), is the first such device made. A special resistive readout array designed here permits signals from the 256 anode pads in each PSPMT to be read out on only 16 data lines. Preliminary tests of uniformity, sensitivity and resolution will be described along with initial images of mice obtained with this new device. [Preview Abstract] |
Thursday, October 11, 2007 2:36PM - 2:48PM |
BH.00004: Polarization and Relaxation of Radon Eric Tardiff, Timothy Chupp, Wolfgang Lorenzon, Sarah Nuss-Warren, John Behr, Matthew Pearson, Kerim Gulyuz, Richard Lefferts, Norbert Pietralla, Georgi Rainovski, Jerry Sell, Gene Sprouse The polarization and relaxation of $^{209}$Rn collected in coated and uncoated glass optical pumping cells was studied at SUNY Stony Brook's Francium Lab. On the order of one million atoms per shot were collected and polarized by spin exchange with laser-polarized rubidium. Gamma-ray anisotropies were measured as a signal of the alignment (the second order moment of the polarization) resulting from the combination of polarization and quadrupole relaxation at the cell walls. The temperature dependence over the range 130$^\circ$C to 220$^\circ$C shows the anisotropies increasing with increasing temperature as the ratio of the spin exchange polarization rate to the wall relaxation rate increases faster than the rubidium polarization decreases. Subsequent rubidium fluorescence polarimetry studies determine the level of rubidium polarization in the cells under similar conditions. Polarization relaxation rates, promising for electric dipole moment measurements of octupole-deformed radon isotopes, have been extracted from the gamma-ray data, and improved limits on the multipole mixing ratios of some of the main gamma-ray transitions have been determined. [Preview Abstract] |
Thursday, October 11, 2007 2:48PM - 3:00PM |
BH.00005: Updated Decay Data Library for Actinides F.G. Kondev, I. Ahmad, J.P. Greene, A.L. Nichols, M.A. Kellett Accurate decay data for actinide nuclides and their decay chains are important in the nuclear fuel cycles of both thermal and fast reactors. These data have also found increasing application in many other power-related fields such as fuel manufacture and reprocessing, waste storage and management, nuclear facility design, safety assessments and safeguards/proliferation issues. Specific requirements for improved actinide decay data have been outlined in a recent review by Nichols [1]. As a consequence of this review and debate within the nuclear data community, an IAEA Coordinated Research Project (CRP) on ``Updated Decay Data Library for Actinides'' was initiated in October 2005. Staff from various research laboratories in seven countries and one international body are involved in these efforts to quantify with greater accuracy the complete decay data for almost 40 actinides and 45 of their daughters. An overview of the IAEA CRP programme will be presented, including the present status of the on-going work. Results from new measurements of the decay properties of a number of nuclei, such as $^{240}$Pu, $^{243-246}$Cm and $^{249,250}$Cf, will also be presented and discussed. This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357. \newline [1] A.L. Nichols, Appl. Radiat. Isot. 55, 23-70 (2001). [Preview Abstract] |
Thursday, October 11, 2007 3:00PM - 3:12PM |
BH.00006: Neutron-Induced Partial Gamma-Ray Cross-Section Measurements on Uranium at TUNL A. Hutcheson, A.S. Crowell, J.H. Esterline, B. Fallin, C.R. Howell, M. Kiser, A.P. Tonchev, W. Tornow, J.H. Kelley, C.T. Angell, M. Boswell, H.J. Karwowski, R.S. Pedroni, G.J. Weisel, J.A. Becker, D. Dashdorj, R.A. Macri, R.O. Nelson Precision measurements have been performed on $^{235,238}$U targets at Triangle Universities Nuclear Laboratory using a and monoenergetic neutron beam. The excitation function of (n,2n) reaction has been studied with incident energies between 5 and 15 MeV and beam flux of 104 n s$^{-1}$ cm$^{-2}$ at target position. Multiple (n,n') and (n,2n) partial cross sections have been measured using clover and planar HPGE detectors in this energy range, and results will be compared with the Hauser-Feshbach model. A more in-depth explanation of the techniques and analysis will be presented. [Preview Abstract] |
Thursday, October 11, 2007 3:12PM - 3:24PM |
BH.00007: Measurement of the $^{241}$Am(n,2n) reaction cross section from 7.6 to 14.5 MeV A. Tonchev, C. Angell, J. Becker, E. Bond, D. Dashdorj, B. Fallin, J. Fitzpatrick, C. Howell, A. Hutcheson, H. Karwowski, J. Kelley, R. Macri, R. Pedroni, A. Slemmons, M. Stoyer, W. Tornow, D. Vieira, J. Wilhelmy, C. Wu High-precision measurements of the $^{241}$Am(n,2n)$^{240}$Am reaction have been performed with neutron energies from 7.6 to 14.5 MeV. The monoenergetic neutron beams were produced via the $^{2}$H(d,n)$^{3}$He reaction using the 10 MV Tandem accelerator at TUNL. The radioactive targets consisted of 1mg highly-enriched $^{241}$Am, sandwiched between three different thin monitor foils. They were irradiated with a neutron flux of 3x10$^{7}$ n cm$^{-2}$s$^{-1}$. After each irradiation the induced activity in the targets and monitors was measured off-line with 60{\%} HPGe detectors. Our neutron induced cross sections will be compared with recent literature results and statistical model calculations. [Preview Abstract] |
Thursday, October 11, 2007 3:24PM - 3:36PM |
BH.00008: The Explanation of Quantum Teleportation and Entanglement Swapping Russell Moon, Victor Vasiliev According to the Vortex Theory, the rotation of a particle causes the surrounding three-dimensional space to rotate creating the particle's electromagnetic characteristic. Because three-dimensional space is the surface of fourth-dimensional space, this rotation extends slightly downward into the fourth-dimensional volume beneath. If two photons possessing complementary polarizations are ``entangled'', this extreme closeness forces their rotations extending into fourth-dimensional space to join together forming a vortex. When the particles are separated, the vortex between them remains. A change in the orientation of a photon at one end of the vortex travels in a wave down the length of the vortex creating a change in the orientation of the photon at the other end. Entangled separated particles of matter such as electrons are similarly connected and effected by each other. The breaking and reconnecting of these vortices also explains the phenomenon of entanglement swapping. 1 R.G. Moon, \textit{The Possible Existence of a New Particle: the Neutral Pentaquark}? Book of materials, The Scientific Seminar Ecology and Space 1, February 22, 2005, Saint-Petersburg, Russia, 2005. [Preview Abstract] |
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