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Selected Works

2018

Nuclear

Articles 1 - 6 of 6

Full-Text Articles in Physics

Tim_Rinn_Final_Disertation.Pdf, Timothy T. Rinn Nov 2018

Tim_Rinn_Final_Disertation.Pdf, Timothy T. Rinn

Timothy Rinn

No abstract provided.

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Search For The Neutron Decay N → X + Γ , Where X Is A Dark Matter Particle, Zhoawen Tang, Marie Blatnik, Leah J. Broussard, J. H. Choi, Stephen M. Clayton, Christopher Cude-Woods, Scott Currie, D. E. Fellers, E. M. Fries, Peter Geltenbort, F. Gonzalez, Kevin P. Hickerson, Takeyasu M. Ito, Chen Y. Liu, S. W. T. Macdonald, Mark Makela, Christopher L. Morris, C. M. O'Shaughnessy, Robert W. Pattie Jr., Bradley R. Plaster, D. J. Salvat, Alexander Saunders, Zhehui Wang, Albert R. Young, B. A. Zeck Jul 2018

Search For The Neutron Decay N → X + Γ , Where X Is A Dark Matter Particle, Zhoawen Tang, Marie Blatnik, Leah J. Broussard, J. H. Choi, Stephen M. Clayton, Christopher Cude-Woods, Scott Currie, D. E. Fellers, E. M. Fries, Peter Geltenbort, F. Gonzalez, Kevin P. Hickerson, Takeyasu M. Ito, Chen Y. Liu, S. W. T. Macdonald, Mark Makela, Christopher L. Morris, C. M. O'Shaughnessy, Robert W. Pattie Jr., Bradley R. Plaster, D. J. Salvat, Alexander Saunders, Zhehui Wang, Albert R. Young, B. A. Zeck

Robert W. Pattie Jr.

Fornal and Grinstein recently proposed that the discrepancy between two different methods of neutron lifetime measurements, the beam and bottle methods, can be explained by a previously unobserved dark matter decay mode, n→X+γ. We perform a search for this decay mode over the allowed range of energies of the monoenergetic γ ray for X to be dark matter. A Compton-suppressed high-purity germanium detector is used to identify γ rays from neutron decay in a nickel-phosphorous-coated stainless-steel bottle. A combination of Monte Carlo and radioactive source calibrations is used to determine the absolute efficiency for detecting γ …

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Search For Dark Matter Decay Of The Free Neutron From The Ucna Experiment: N → Χ + E^+E^−, Xiaohui Sun, Edith Adamek, Bruno Allgeier, Matthias A. Blatnik, Thomas J. Bowles, Leah J. Broussard, Matthew A. Brown, Richard Carr, Steven M. Clayton, Chris Cude-Woods, Sonja Currie, Eric B. Dees, Xingxing Ding, Bradley W. Filippone, A. Bello García, Peter Geltenbort, Salajeghe Hasan, Kevin P. Hickerson, J. Todd Hoagland, R. Hong, Gary E. Hogan, Anthony T. Holley, Takeyasu M. Ito, Amanda L. Knecht, Chao-Yu Liu, Jingyang Liu, María Makela, Russel Mammei, J. W. Martin, Dan Melconian, Michael P. Mendenhall, Stephen D. Moore, Charles L. Morris, Sushil Nepal, N. Vahedi Nouri, Robert W. Pattie Jr., A. Pérez Galván, David G. Phillips, Richard H. Picker, Margaret L. Pitt, Blakely A. Plaster, Jana C. Ramsey, R. Barreto Rios, Daniel J. Salvat, Andy Saunders, Walter Sondheim, S. Sjue, Steven Slutsky, Charles Swank, Gyani Swift, E. Tatar, R. Bruce Vogelaar, Brittany Vorndick, Z. Wang, Wanchun Wei, J. Wexler, T. Womack, Christopher Wrede, Andrew R. Young, B. A. Zeck May 2018

Search For Dark Matter Decay Of The Free Neutron From The Ucna Experiment: N → Χ + E^+E^−, Xiaohui Sun, Edith Adamek, Bruno Allgeier, Matthias A. Blatnik, Thomas J. Bowles, Leah J. Broussard, Matthew A. Brown, Richard Carr, Steven M. Clayton, Chris Cude-Woods, Sonja Currie, Eric B. Dees, Xingxing Ding, Bradley W. Filippone, A. Bello García, Peter Geltenbort, Salajeghe Hasan, Kevin P. Hickerson, J. Todd Hoagland, R. Hong, Gary E. Hogan, Anthony T. Holley, Takeyasu M. Ito, Amanda L. Knecht, Chao-Yu Liu, Jingyang Liu, María Makela, Russel Mammei, J. W. Martin, Dan Melconian, Michael P. Mendenhall, Stephen D. Moore, Charles L. Morris, Sushil Nepal, N. Vahedi Nouri, Robert W. Pattie Jr., A. Pérez Galván, David G. Phillips, Richard H. Picker, Margaret L. Pitt, Blakely A. Plaster, Jana C. Ramsey, R. Barreto Rios, Daniel J. Salvat, Andy Saunders, Walter Sondheim, S. Sjue, Steven Slutsky, Charles Swank, Gyani Swift, E. Tatar, R. Bruce Vogelaar, Brittany Vorndick, Z. Wang, Wanchun Wei, J. Wexler, T. Womack, Christopher Wrede, Andrew R. Young, B. A. Zeck

Robert W. Pattie Jr.

It has been proposed recently that a previously unobserved neutron decay branch to a dark matter particle (χ) could account for the discrepancy in the neutron lifetime observed in experiments that use two different measurement techniques. One of the possible final states discussed includes a single χalong with an e+e− pair. We use data from the UCNA (Ultracold Neutron Asymmetry) experiment to set limits on this decay channel. Coincident electron-like events are detected with ∼4π acceptance using a pair of detectors that observe a volume of stored ultracold neutrons. The summed kinetic energy …

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Hyperpolarization Of Silicon Nanoparticles With Tempo Radicals, Jingzhe Hu, Nicholas Whiting, Pratip Bhattacharya Mar 2018

Hyperpolarization Of Silicon Nanoparticles With Tempo Radicals, Jingzhe Hu, Nicholas Whiting, Pratip Bhattacharya

Nicholas Whiting

Silicon-based particles can be hyperpolarized via dynamic nuclear polarization to enhance 29Si magnetic resonance signals. Application of this technique to nanoscale silicon particles has been limited because of the low signal enhancements achieved; it is hypothesized that this is due to the low number of endogenous electronic defects inherent to the particles. We introduce a method of incorporating exogenous radicals into silicon nanoparticle suspensions in order to improve the hyperpolarization of 29Si nuclear spins to levels sufficient for in vivo MR imaging. Calibration of radical concentrations and polarization times are reported for a variety of silicon particle sizes (30−200 nm …

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Performance Of The Upgraded Ultracold Neutron Source At Los Alamos National Laboratory And Its Implication For A Possible Neutron Electric Dipole Moment Experiment, Takeyasu M. Ito, Evan R. Adamek, Nathan B. Callahan, J. H. Choi, Stephen M. Clayton, Chris Cude-Woods, Scott Currie, Xinjian Ding, D. E. Fellers, Peter Geltenbort, Steve K. Lamoreaux, C. Y. Liu, S. Macdonald, Mark Makela, Charles L. Morris, Robert W. Pattie Jr., John Clinton Ramsey, Daniel J. Salvat, Andy Saunders, Edward I. Sharapov, S. Sjue, A. P. Sprow, Zebo Tang, H. L. Weaver, Wanchun Wei, Andrew R. Young Jan 2018

Performance Of The Upgraded Ultracold Neutron Source At Los Alamos National Laboratory And Its Implication For A Possible Neutron Electric Dipole Moment Experiment, Takeyasu M. Ito, Evan R. Adamek, Nathan B. Callahan, J. H. Choi, Stephen M. Clayton, Chris Cude-Woods, Scott Currie, Xinjian Ding, D. E. Fellers, Peter Geltenbort, Steve K. Lamoreaux, C. Y. Liu, S. Macdonald, Mark Makela, Charles L. Morris, Robert W. Pattie Jr., John Clinton Ramsey, Daniel J. Salvat, Andy Saunders, Edward I. Sharapov, S. Sjue, A. P. Sprow, Zebo Tang, H. L. Weaver, Wanchun Wei, Andrew R. Young

Robert W. Pattie Jr.

The ultracold neutron (UCN) source at Los Alamos National Laboratory (LANL), which uses solid deuterium as the UCN converter and is driven by accelerator spallation neutrons, has been successfully operated for over 10 years, providing UCN to various experiments, as the first production UCN source based on the superthermal process. It has recently undergone a major upgrade. This paper describes the design and performance of the upgraded LANL UCN source. Measurements of the cold neutron spectrum and UCN density are presented and compared to Monte Carlo predictions. The source is shown to perform as modeled. The UCN density measured at …

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Hyperpolarized Porous Silicon Nanoparticles: Potential Theragnostic Material For 29si Magnetic Resonance Imaging, Hyeonglim Seo, Ikjang Choi, Nicholas Whiting, Jingzhe Hu, Quy S. Luu, Shivanand Pudakalakatti, Caitlin Mccowan, Yaewon Kim, Niki Zacharias Millward, Seunghyun Lee, Pratip Bhattacharya, Youngbok Lee Dec 2017

Hyperpolarized Porous Silicon Nanoparticles: Potential Theragnostic Material For 29si Magnetic Resonance Imaging, Hyeonglim Seo, Ikjang Choi, Nicholas Whiting, Jingzhe Hu, Quy S. Luu, Shivanand Pudakalakatti, Caitlin Mccowan, Yaewon Kim, Niki Zacharias Millward, Seunghyun Lee, Pratip Bhattacharya, Youngbok Lee

Nicholas Whiting

Porous silicon nanoparticles have recently garnered attention as potentially-promising biomedical platforms for drug delivery and medical diagnostics. Here, we demonstrate porous silicon nanoparticles as contrast agents for 29Si magnetic resonance imaging. Size-controlled porous silicon nanoparticles were synthesized by magnesiothermic reduction of silica nanoparticles and were surface activated for further functionalization. Particles were hyperpolarized via dynamic nuclear polarization to enhance their 29Si MR signals; the particles demonstrated long 29Si spin-lattice relaxation (T1) times (~25 mins), which suggests potential applicability for medical imaging. Furthermore, 29Si hyperpolarization levels were sufficient to allow 29Si MRI in phantoms. These results underscore the potential of porous …

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