Bulletin of the American Physical Society
2018 Annual Meeting of the APS Four Corners Section
Volume 63, Number 16
Friday–Saturday, October 12–13, 2018; University of Utah, Salt Lake City, Utah
Session L06: Nuclear Physics |
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Chair: Eric Hirschmann, Brigham Young University Room: CSC 210 |
Saturday, October 13, 2018 11:20AM - 11:44AM |
L06.00001: Laser-driven pulsed neutrons for detection of nuclear material Invited Speaker: Andrea Favalli At Los Alamos National Laboratory (LANL), we have pioneered a short duration yet extremely intense neutron source using a short-pulse laser. At the Trident laser facility, one of the most intense and powerful short-pulse lasers in the world, a laser beam can be concentrated to peak intensity up to 1021 W/cm2. The beam, interacting with an ultrathin (sub-micron) deuterated plastic foil target, drives a high-energy deuteron beam, which produces neutrons in a beryllium converter. This neutron source features high intensity and directionality, >1010 fast neutrons per sr per shot, with extremely short neutron pulse duration i.e. on the order of a few nanoseconds. One of the motivations for such a source is the capability to perform nondesctructive assay of special nuclear material for nuclear material accountancy, nuclear safeguards and national security applications. Dedicated experimental campaigns were conducted at LANL to investigate the merits and applicability of such an approach to active interrogation of uranium and plutonium materials. Results of these measurements have provided the first of a kind experimental demonstration of active interrogation using high-intensity laser-driven neutron source and demonstrate feasibility of interrogation using a single laser-driven neutron pulse. Presentation will report on laser-plasma acceleration of ions, and subsequent neutron productions, and active interrogation of nuclear material. The experimental results obtained will be presented and discussed. |
Saturday, October 13, 2018 11:44AM - 11:56AM |
L06.00002: Alpha particle formation in neutron star crusts with an improved trial wave function for nuclear Quantum Monte Carlo Cody Lee Petrie, Kevin E Schmidt Quantum Monte Carlo (QMC) calculations have given us insights into many aspects of nuclear physics, from the properties of atomic nuclei to the structure and formation of neutron stars. The combined accuracy and simplicity of the nuclear trial wave function plays a key role in QMC calculations. A more accurate trial wave function could open the door to larger systems and new physics for Auxiliary Field Diffusion Monte Carlo calculations. We have developed a new trial wave function which includes up to 4 correlated particles at a time. We have used this wave function to calculate the binding energies of $^{4}$He, $^{16}$O, $^{40}$Ca, and symmetric nuclear matter at saturation density and show that the energy is decreased for each system compared to calculations with only 2 correlated particles at a time. We also discuss the application of this improved wave function to alpha particle clustering in nearly neutron matter near the transition density between the inner crust and mantel of a neutron star. |
Saturday, October 13, 2018 11:56AM - 12:08PM |
L06.00003: 2.7 years of beta-decay-rate ratio measurements in a controlled environment Quinton Dayle McKnight, Scott Douglas Bergeson, Justin Peatross, Michael Ware We report nearly continuous beta-decay-rate measurements of Na-22, Cl-36, Co-60, Sr-90, and Cs-137 over a period of 2.7 years using four Geiger-Muller tubes. We carefully control the ambient pressure and temperature for the detectors, sources, and electronics in order to minimize environmentally-dependent systematic drifts in the measurement chains. We show that the amplitudes of an annual oscillation in the decay rates are zero with an uncertainty of 0.004%. |
Saturday, October 13, 2018 12:08PM - 12:20PM |
L06.00004: Tests of \textit{ab initio} nuclear theory via the isobaric multiplet mass equation in $T=1$ superallowed beta decay systems Matthew S Martin, Kyle G Leach, Jason D Holt Precision measurements of superallowed $0^+\to0^+$ nuclear beta decay currently provide the most precise value of the vector coupling in the weak interaction. The extraction of this quantity from these experiments assume that isospin symmetry is exact, thus requiring that theoretical isospin-symmetry-breaking (ISB) corrections must be applied.
Using \textit{ab initio} chiral effective field theory methods to calculate binding energies of the $T=1$ superallowed beta chain and the isobaric multiplet mass equation we hope to extract ISB corrections to $\mathcal{F}t$ values and compare to experimental data. This should give enough confidence in the \textit{ab initio} methods to perform precise Standard Model tests of the weak interaction. |
Saturday, October 13, 2018 12:20PM - 12:32PM |
L06.00005: The discontinuities in twist-3 GPDs Fatma Aslan, Matthias Burkardt We find in one-loop calculations and spectator models that twist-3 GPDs exhibit discontinuities. In the forward limit these discontinuities grow into Dirac delta functions. Neglecting these Dirac delta functions leads to an apparent violation of sum rules for twist-3 PDFs. We calculate quasi-PDFs and identify the Dirac delta function terms with momentum components in the nucleon state that do not scale as the nucleon is boosted to the infinite momentum frame. |
Saturday, October 13, 2018 12:32PM - 12:44PM |
L06.00006: Graphic Methods for Electrical Pulse Classification Michael Vernon Nelson Research projects in many fields, such as nuclear physics, where this project originated, have to analyze mass amounts of data with very little of it being of interest. Thousands of fission events can be observed and recorded in a second, and yet perhaps only a few events of interest happen per minute. Still, every individual event must be analyzed to some degree before being set aside, and thousands of targeted events must still be found, identified, recorded, and analyzed in detail. This presentation will outline some of the difficulties in data analysis and visualization that were encountered and will demonstrate some of the more useful and interesting techniques learned to handle them. These include the automation of non-critical event analysis, data visualization, and optimization methods for mathematical analysis of mass data. Data visualization techniques will be covered in special detail, with an emphasis on the usefulness of charts and graphs in both data visualization and filtering. |
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