Open Access. Powered by Scholars. Published by Universities.®

Physics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 30 of 34

Full-Text Articles in Physics

Ucna/Ucna+, Robert Pattie Aug 2019

Ucna/Ucna+, Robert Pattie

Robert W. Pattie Jr.

The neutron provides a simple yet dynamic nuclear system to study the Standard Model of Particle Physics. The process of transforming a neutron into a proton, an electron, and an anti-neutrino contains a wealth of information in the decay rate and the kinematics of the emitted particles. Precision measurements of angular correlations in neutron β-decay can lend insight to the structure of the weak interaction and probe for physics beyond the Standard Model. The UCNA experiment at the Los Alamos Neutron Science Center is the only experiment to use ultracold neutrons to perform such a measurement, determining the β-asymmetry parameter ...


Solid Deuterium Surface Degradation At Ultracold Neutron Sources, Alexander Anghel, Thomas L. Bailey, George Bison, Bertrand Blau, Leah J. Broussard, Stephen M. Clayton, Christopher Cude-Woods, Manfred Daum, Ayman I. Hawari, Nora Hild, Paul R. Huffman, Takeyasu M. Ito, Klaus Kirch, E. Korobkina, Bernhard Lauss, Kent Leung, E. M. Lutz, Mark Makela, G. Medlin, C. L. Morris, Robert W. Pattie, Dieter Ries, Alexander Saunders, Phillip Schmidt-Wellenburg, Vadim Talanov, Albert R. Young, Bernard Wehring, C. White, Michael Wohlmuther, Geza Zsigmond Aug 2018

Solid Deuterium Surface Degradation At Ultracold Neutron Sources, Alexander Anghel, Thomas L. Bailey, George Bison, Bertrand Blau, Leah J. Broussard, Stephen M. Clayton, Christopher Cude-Woods, Manfred Daum, Ayman I. Hawari, Nora Hild, Paul R. Huffman, Takeyasu M. Ito, Klaus Kirch, E. Korobkina, Bernhard Lauss, Kent Leung, E. M. Lutz, Mark Makela, G. Medlin, C. L. Morris, Robert W. Pattie, Dieter Ries, Alexander Saunders, Phillip Schmidt-Wellenburg, Vadim Talanov, Albert R. Young, Bernard Wehring, C. White, Michael Wohlmuther, Geza Zsigmond

Robert W. Pattie Jr.

Solid deuterium (sD  is used as an efficient converter to produce ultracold neutrons (UCN). It is known that the sD must be sufficiently cold, of high purity and mostly in its ortho-state in order to guarantee long lifetimes of UCN in the solid from which they are extracted into vacuum. Also the UCN transparency of the bulk sD  material must be high because crystal inhomogeneities limit the mean free path for elastic scattering and reduce the extraction efficiency. Observations at the UCN sources at Paul Scherrer Institute and at Los Alamos National Laboratory consistently show a decrease of the UCN ...


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, nX+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 rays arising ...


Status Of The Ucnτ Experiment, Robert W. Pattie Jr. May 2018

Status Of The Ucnτ Experiment, Robert W. Pattie Jr.

Robert W. Pattie Jr.

The neutron is the simplest nuclear system that can be used to probe the structure of the weak interaction and search for physics Beyond the Standard Model. Measurements of neutron lifetime and β-decay correlation coefficients with precisions of 0.02% and 0.1%, respectively, would allow for stringent constraints on new physics. The UCNτ experiment uses an asymmetric magneto-gravitational UCN trap with in situ counting of surviving neutrons to measure the neutron lifetime, \tau_n=877.7(0.7)_{stat}(+0.3 /-0.1 )_{sys}s. I will discuss the recent result from UCNτ, the status ...


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 (Ee+e) from ...


Measurement Of The Neutron Lifetime Using A Magneto-Gravitational Trap And In Situ Detection, Robert W. Pattie Jr., Nathan B. Callahan, Chris Cude-Woods, Edith R. Adamek, Leah J. Broussard, Stephen M. Clayton, Scott A. Currie, Eric B. Dees, Xiaoping Ding, Egbert M. Engel, D. E. Fellers, William Fox, Peter Geltenbort, Kevin P. Hickerson, Mark A. Hoffbauer, Anthony T. Holley, A. Komives, Chen Liu, S. W. T. Macdonald, Mark Makela, Christopher L. Morris, Joseph D. Ortiz, John C. Ramsey, Daniel J. Salvat, Alexander Saunders, Susan J. Seestrom, E. I. Sharapov, S. K. Sjue, Zebo Tang, J. Vanderwerp, Bruce Vogelaar, P. L. Walstrom, Zhehui Wang, Wei Wei, H. L. Weaver, Judith W. Wexler, Tanner L. Womack, Andrew R. Young, B. A. Zeck May 2018

Measurement Of The Neutron Lifetime Using A Magneto-Gravitational Trap And In Situ Detection, Robert W. Pattie Jr., Nathan B. Callahan, Chris Cude-Woods, Edith R. Adamek, Leah J. Broussard, Stephen M. Clayton, Scott A. Currie, Eric B. Dees, Xiaoping Ding, Egbert M. Engel, D. E. Fellers, William Fox, Peter Geltenbort, Kevin P. Hickerson, Mark A. Hoffbauer, Anthony T. Holley, A. Komives, Chen Liu, S. W. T. Macdonald, Mark Makela, Christopher L. Morris, Joseph D. Ortiz, John C. Ramsey, Daniel J. Salvat, Alexander Saunders, Susan J. Seestrom, E. I. Sharapov, S. K. Sjue, Zebo Tang, J. Vanderwerp, Bruce Vogelaar, P. L. Walstrom, Zhehui Wang, Wei Wei, H. L. Weaver, Judith W. Wexler, Tanner L. Womack, Andrew R. Young, B. A. Zeck

Robert W. Pattie Jr.

The precise value of the mean neutron lifetime, tn, plays an important role in nuclear and particle physics and cosmology. It is used to predict the ratio of protons to helium atoms in the primordial universe and to search for physics beyond the Standard Model of particle physics. We eliminated loss mechanisms present in previous trap experiments by levitating polarized ultracold neutrons above the surface of an asymmetric storage trap using a repulsive magnetic field gradient so that the stored neutrons do not interact with material trap walls. As a result of this approach and the use of an in ...


New Result For The Neutron Β -Asymmetry Parameter A 0 From Ucna, Michael Brown, E. B. Dees, E. Adamek, B. Allgeier, M. Blatnik, Thomas J. Bowles, L. J. Broussard, Richard Carr, Stephen M. Clayton, C. Cude-Woods, S. A. Currie, Xiaoping Ding, B. W. Filippone, A. Garcia, Peter Geltenbort, Siraj S. Hasan, Kevin P. Hickerson, J. Hoagland, R. Hong, Gary E. Hogan, A. T. Holley, Takeyasu M. Ito, A. Knecht, C.-Y. Liu, J. Liu, M. Makela, J. W. Martin, Daniel G. Melconian, M. P. Mendenhall, S. D. Moore, Sandhya Nepal, N. Nouri, Robert W. Pattie Jr., A. Pérez Galván, David G. Phillips, Richard H. Picker, Margaret L. Pitt, Bradley R. Plaster, J. C. Ramsey, R. Rios, Daniel J. Salvat, Andy Saunders, Walter E. Sondheim, S.J. Seestrom, Sky Sjue, Steven Slutsky, Xiaohui Sun, Charles Swank, Gyani Swift, E. Tatar, R. Bruce Vogelaar, Brittany Vorndick, Z. Wang, J. Wexler, Tanner Womack, Christopher Wrede, Albert Young, B.A. Zeck Mar 2018

New Result For The Neutron Β -Asymmetry Parameter A 0 From Ucna, Michael Brown, E. B. Dees, E. Adamek, B. Allgeier, M. Blatnik, Thomas J. Bowles, L. J. Broussard, Richard Carr, Stephen M. Clayton, C. Cude-Woods, S. A. Currie, Xiaoping Ding, B. W. Filippone, A. Garcia, Peter Geltenbort, Siraj S. Hasan, Kevin P. Hickerson, J. Hoagland, R. Hong, Gary E. Hogan, A. T. Holley, Takeyasu M. Ito, A. Knecht, C.-Y. Liu, J. Liu, M. Makela, J. W. Martin, Daniel G. Melconian, M. P. Mendenhall, S. D. Moore, Sandhya Nepal, N. Nouri, Robert W. Pattie Jr., A. Pérez Galván, David G. Phillips, Richard H. Picker, Margaret L. Pitt, Bradley R. Plaster, J. C. Ramsey, R. Rios, Daniel J. Salvat, Andy Saunders, Walter E. Sondheim, S.J. Seestrom, Sky Sjue, Steven Slutsky, Xiaohui Sun, Charles Swank, Gyani Swift, E. Tatar, R. Bruce Vogelaar, Brittany Vorndick, Z. Wang, J. Wexler, Tanner Womack, Christopher Wrede, Albert Young, B.A. Zeck

Robert W. Pattie Jr.

Background: The neutron β-decay asymmetry parameter A0 defines the angular correlation between the spin of the neutron and the momentum of the emitted electron. Values for A0 permit an extraction of the ratio of the weak axial-vector to vector coupling constants, λgA/gV, which under assumption of the conserved vector current hypothesis (gV=1) determines gA. Precise values for gA are important as a benchmark for lattice QCD calculations and as a test of the standard model.

Purpose: The UCNA experiment, carried out at the Ultracold Neutron (UCN) source at the ...


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 ...


First Direct Constraints On Fierz Interference In Free-Neutron Β Decay, Kevin P. Hickerson, Xiaohui Sun, Yelena Bagdasarova, David Bravo-Berguño, Leah J. Broussard, Peter Brown, Richard Carr, Scott Currie, Xinjian Ding, Bradley W. Filippone, Alejandro García, Peter Geltenbort, J. Todd Hoagland, A. T. Holley, Ran Hong, Takeyasu M. Ito, Andreas Knecht, Chao-Yu Liu, Jiang-Lai Liu, Mark Makela, Russell R. Mammei, J. W. Martin, Dan Melconian, Michael P. Mendenhall, Spencer D. Moore, Christopher L. Morris, Robert W. Pattie, A. Pérez Galván, Ruediger Picker, Margaret L. Pitt, Bradley R. Plaster, John C. Ramsey, Roger H. Rios, A. Saunders, Susan J. Seestrom, Eduard I. Sharapov, Walter E. Sondheim, Erdinch Tatar, R. Bruce Vogelaar, Brittney Vorndick, Christopher Wrede, Andrew R. Young, B. A. Zeck Nov 2017

First Direct Constraints On Fierz Interference In Free-Neutron Β Decay, Kevin P. Hickerson, Xiaohui Sun, Yelena Bagdasarova, David Bravo-Berguño, Leah J. Broussard, Peter Brown, Richard Carr, Scott Currie, Xinjian Ding, Bradley W. Filippone, Alejandro García, Peter Geltenbort, J. Todd Hoagland, A. T. Holley, Ran Hong, Takeyasu M. Ito, Andreas Knecht, Chao-Yu Liu, Jiang-Lai Liu, Mark Makela, Russell R. Mammei, J. W. Martin, Dan Melconian, Michael P. Mendenhall, Spencer D. Moore, Christopher L. Morris, Robert W. Pattie, A. Pérez Galván, Ruediger Picker, Margaret L. Pitt, Bradley R. Plaster, John C. Ramsey, Roger H. Rios, A. Saunders, Susan J. Seestrom, Eduard I. Sharapov, Walter E. Sondheim, Erdinch Tatar, R. Bruce Vogelaar, Brittney Vorndick, Christopher Wrede, Andrew R. Young, B. A. Zeck

Robert W. Pattie Jr.

Precision measurements of free-neutron β decay have been used to precisely constrain our understanding of the weak interaction. However, the neutron Fierz interference term bn, which is particularly sensitive to beyond-standard-model tensor currents at the TeV scale, has thus far eluded measurement. Here we report the first direct constraints on this term, finding bn=0.067±0.005stat+0.090−0.061sys, consistent with the standard model. The uncertainty is dominated by absolute energy reconstruction and the linearity of the β spectrometer energy response.


Evaluation Of Commercial Nickel–Phosphorus Coating For Ultracold Neutron Guides Using A Pinhole Bottling Method, Robert W. Pattie, Evan R. Adamek, T. Brenner, A. Brandt, Leah J. Broussard, Nathan Callahan, Stephen M. Clayton, Chris Cude-Woods, Scott A. Currie, Peter Geltenbort, Takeyasu M. Ito, T. Lauer, Chenyu Liu, Jaroslaw Majewski, Mark F. Makela, Yasuhiro Masuda, Christopher L. Morris, John C. Ramsey, Daniel J. Salvat, Alexander Saunders, Juri Schroffenegger, Zebo Tang, Wanchun Wei, Zhehui Wang, Erik B. Watkins, Albert R. Young, B.A. Zeck Aug 2017

Evaluation Of Commercial Nickel–Phosphorus Coating For Ultracold Neutron Guides Using A Pinhole Bottling Method, Robert W. Pattie, Evan R. Adamek, T. Brenner, A. Brandt, Leah J. Broussard, Nathan Callahan, Stephen M. Clayton, Chris Cude-Woods, Scott A. Currie, Peter Geltenbort, Takeyasu M. Ito, T. Lauer, Chenyu Liu, Jaroslaw Majewski, Mark F. Makela, Yasuhiro Masuda, Christopher L. Morris, John C. Ramsey, Daniel J. Salvat, Alexander Saunders, Juri Schroffenegger, Zebo Tang, Wanchun Wei, Zhehui Wang, Erik B. Watkins, Albert R. Young, B.A. Zeck

Robert W. Pattie Jr.

We report on the evaluation of commercial electroless nickel phosphorus (NiP) coatings for ultracold neutron (UCN) transport and storage. The material potential of 50μm thick NiP coatings on stainless steel and aluminum substrates was measured to be V F=213(5.2)neV using the time-of-flight spectrometer ASTERIX at the Lujan Center. The loss per bounce probability was measured in pinhole bottling experiments carried out at ultracold neutron sources at Los Alamos Neutron Science Center and the Institut Laue-Langevin. For these tests a new guide coupling design was used to minimize gaps between the guide sections. The observed UCN loss ...


A New Method For Measuring The Neutron Lifetime Using An In Situ Neutron Detector, Christopher L. Morris, Edith R. Adamek, Leah J. Broussard, Nathan B. Callahan, Stephen M. Clayton, Chris Cude-Woods, Scott A. Currie, Xiaoping Ding, Walter Fox, Kevin P. Hickerson, Mark A. Hoffbauer, Anthony T. Holley, A. Komives, Chen Y. Liu, Mark Makela, Robert W. Pattie, John C. Ramsey, Daniel J. Salvat, Alexander Saunders, Susan J. Seestrom, E. I. Sharapov, S. K. Sjue, Zhijing Tang, J. Vanderwerp, R. Bruce Vogelaar, Peter L. Walstrom, Zhehui Wang, Wanchun Wei, Judith W. Wexler, Tanner L. Womack, Andrew R. Young, B. A. Zeck May 2017

A New Method For Measuring The Neutron Lifetime Using An In Situ Neutron Detector, Christopher L. Morris, Edith R. Adamek, Leah J. Broussard, Nathan B. Callahan, Stephen M. Clayton, Chris Cude-Woods, Scott A. Currie, Xiaoping Ding, Walter Fox, Kevin P. Hickerson, Mark A. Hoffbauer, Anthony T. Holley, A. Komives, Chen Y. Liu, Mark Makela, Robert W. Pattie, John C. Ramsey, Daniel J. Salvat, Alexander Saunders, Susan J. Seestrom, E. I. Sharapov, S. K. Sjue, Zhijing Tang, J. Vanderwerp, R. Bruce Vogelaar, Peter L. Walstrom, Zhehui Wang, Wanchun Wei, Judith W. Wexler, Tanner L. Womack, Andrew R. Young, B. A. Zeck

Robert W. Pattie Jr.

In this paper, we describe a new method for measuring surviving neutrons in neutron lifetime measurements using bottled ultracold neutrons (UCN), which provides better characterization of systematic uncertainties and enables higher precision than previous measurement techniques. An active detector that can be lowered into the trap has been used to measure the neutron distribution as a function of height and measure the influence of marginally trapped UCN on the neutron lifetime measurement. In addition, measurements have demonstrated phase-space evolution and its effect on the lifetime measurement.


Detection System For Neutron Β Decay Correlations In The Ucnb And Nab Experiments, Leah J. Broussard, B. A. Zeck, Edith R. Adamek, Stephan Baeßler, Noah Birge, Marie Blatnik, J. David Bowman, Astrid E. Brandt, A. E. Brandt, Matthew Brown, John F. Burkhart, Nathan B. Callahan, Steven M. Clayton, Christopher B. Crawford, Chris Cude-Woods, Scott Currie, Eric B. Dees, Xinjian Ding, Nadia Fomin, Emil Frlez, Jason Fry, Frederick E. Gray, Said Hasan, Kevin P. Hickerson, J. Todd Hoagland, Anthony T. Holley, Takeyasu M. Ito, Andreas Klein, Hengne Li, Chenyu Liu, Mark F. Makela, P. L. Mcgaughey, J. Mirabal-Martinez, Charles L. Morris, Jose D. Ortiz, Robert W. Pattie Jr., Seppo I. Penttilä, Brad Plaster, Dinko Počanić, John C. Ramsey, A. Salas-Bacci, Daniel J. Salvat, Alexander Saunders, Susan J. Seestrom, Sky Sjue, Aron Sprow, Z. Tang, R. Bruce Vogelaar, Brittany Vorndick, Z. Wang, Wanchun Wei, J. Wexler, W. S. Wilburn, T. L. Womack, A. R. Young Mar 2017

Detection System For Neutron Β Decay Correlations In The Ucnb And Nab Experiments, Leah J. Broussard, B. A. Zeck, Edith R. Adamek, Stephan Baeßler, Noah Birge, Marie Blatnik, J. David Bowman, Astrid E. Brandt, A. E. Brandt, Matthew Brown, John F. Burkhart, Nathan B. Callahan, Steven M. Clayton, Christopher B. Crawford, Chris Cude-Woods, Scott Currie, Eric B. Dees, Xinjian Ding, Nadia Fomin, Emil Frlez, Jason Fry, Frederick E. Gray, Said Hasan, Kevin P. Hickerson, J. Todd Hoagland, Anthony T. Holley, Takeyasu M. Ito, Andreas Klein, Hengne Li, Chenyu Liu, Mark F. Makela, P. L. Mcgaughey, J. Mirabal-Martinez, Charles L. Morris, Jose D. Ortiz, Robert W. Pattie Jr., Seppo I. Penttilä, Brad Plaster, Dinko Počanić, John C. Ramsey, A. Salas-Bacci, Daniel J. Salvat, Alexander Saunders, Susan J. Seestrom, Sky Sjue, Aron Sprow, Z. Tang, R. Bruce Vogelaar, Brittany Vorndick, Z. Wang, Wanchun Wei, J. Wexler, W. S. Wilburn, T. L. Womack, A. R. Young

Robert W. Pattie Jr.

We describe a detection system designed for precise measurements of angular correlations in neutron β decay. The system is based on thick, large area, highly segmented silicon detectors developed in collaboration with Micron Semiconductor, Ltd. The prototype system meets specifications for β electron detection with energy thresholds below 10 keV, energy resolution of ∼3 keV FWHM, and rise time of ∼50 ns with 19 of the 127 detector pixels instrumented. Using ultracold neutrons at the Los Alamos Neutron Science Center, we have demonstrated the coincident detection of β particles and recoil protons from neutron β decay. The fully instrumented detection ...


Overview Of Neutron Beta Correlation Parameter Analysis From The Ucna Experiment, Xuan Sun, Robert W. Pattie Jr. Jan 2017

Overview Of Neutron Beta Correlation Parameter Analysis From The Ucna Experiment, Xuan Sun, Robert W. Pattie Jr.

Robert W. Pattie Jr.

The UCNA experiment, operated at the Ultracold Neutron Facility at the Los Alamos Neutron Science Center, uses ultracold neutrons (UCN) to measure the free-neutron β-decay correlation parameter, A, between the neutron spin direction and β momentum direction. Measurements of A presently provide the most precise value of gA/gV , the ratio of the axial-vector and vector coupling constants of the nucleon weak interaction. The UCNA experiment has previously analyzed and reported on a measurement of A from a 2010 dataset. Additional datasets were also taken in 2011-2012 and 2012-2013. Improvements in energy calibrations, polarimetry, and statistics are expected to provide ...


Preliminary Results From The Ucnτ Experiment, Robert W. Pattie Jr. Jan 2017

Preliminary Results From The Ucnτ Experiment, Robert W. Pattie Jr.

Robert W. Pattie Jr.

There is currently a 4σ discrepancy between measurements of the neutron lifetime performed using cold neutron beams and those performed with ultracold neutron (UCN) storage vessels. The UCNτ experiment uses an asymmetric magneto-gravitational UCN trap with {\it in situ} counting of surviving neutrons to measure the neutron lifetime. This design eliminates a major systematic of previous bottle experiments related to the loss of UCN on material trap walls and with unloading neutrons from the storage vessel. A new {\it in situ} detection system was used in the 2015-2016 run that was able to measure the population of surviving ...


Total Cross Sections For Ultracold Neutrons Scattered From Gases, Susan J. Seestrom, Evan Adamek, Dave Barlow, Marie Blatnik, Leah Broussard, Nathan Callahan, Steven Clayton, Chris Cude-Woods, Scott A. Currie, Eric Dees, Walt Fox, Mark A. Hoffbauer, Kevin Hickerson, Adam Holley, Chen Y. Liu, Mark F. Makela, Jason J. Medina, Deborah J. Morley, Christopher L. Morris, Robert W. Pattie Jr., John C. Ramsey, A. Roberts, D. J. Salvat, A. Saunders, E. I. Sharapov, S.K.L. Sjue, B. A. Slaughter, P. L. Walstrom, Z. Wang, J. Wexler, T. L. Womack, A. R. Young, J. Vanderwerp, B. A. Zeck Dec 2016

Total Cross Sections For Ultracold Neutrons Scattered From Gases, Susan J. Seestrom, Evan Adamek, Dave Barlow, Marie Blatnik, Leah Broussard, Nathan Callahan, Steven Clayton, Chris Cude-Woods, Scott A. Currie, Eric Dees, Walt Fox, Mark A. Hoffbauer, Kevin Hickerson, Adam Holley, Chen Y. Liu, Mark F. Makela, Jason J. Medina, Deborah J. Morley, Christopher L. Morris, Robert W. Pattie Jr., John C. Ramsey, A. Roberts, D. J. Salvat, A. Saunders, E. I. Sharapov, S.K.L. Sjue, B. A. Slaughter, P. L. Walstrom, Z. Wang, J. Wexler, T. L. Womack, A. R. Young, J. Vanderwerp, B. A. Zeck

Robert W. Pattie Jr.

We have followed up on our previous measurements of upscattering of ultracold neutrons (UCN) from a series of gases by making measurements of total cross sections on the following gases hydrogen, ethane, methane, isobutene, n-butane, ethylene, water vapor, propane, neopentane, isopropyl alcohol, and 3 He. The values of these cross sections are important for estimating the loss rate of trapped neutrons due to residual gas and are relevant to neutron lifetime measurements using UCN. The effects of the UCN velocity and path-length distributions were accounted for in the analysis using a Monte Carlo transport code. Results are compared to our ...


Position-Sensitive Detection Of Ultracold Neutrons With An Imaging Camera And Its Implications To Spectroscopy, Wanchun Wei, Leah J. Broussard, Mark A. Hoffbauer, Mark Makela, Charles L. Morris, Zebo Tang, Evan R. Adamek, Nathan B. Callahan, Stephen M. Clayton, Chris Cude-Woods, Scott Currie, Eric B. Dees, Xinjian Ding, Peter Geltenbort, Kevin P. Hickerson, Anthony T. Holley, Takeyasu M. Ito, Kent K. Leung, Chenyu Y. Liu, Deborah J. Morley, Jose D. Ortiz, Robert W. Pattie, John C. Ramsey, Alexander Saunders, Susan J. Seestrom, Eduard I. Sharapov, S. K. Sjue, Judith Wexler, Tanner L. Womack, Albert R. Young, B. A. Zeck, Zhehui Wang Sep 2016

Position-Sensitive Detection Of Ultracold Neutrons With An Imaging Camera And Its Implications To Spectroscopy, Wanchun Wei, Leah J. Broussard, Mark A. Hoffbauer, Mark Makela, Charles L. Morris, Zebo Tang, Evan R. Adamek, Nathan B. Callahan, Stephen M. Clayton, Chris Cude-Woods, Scott Currie, Eric B. Dees, Xinjian Ding, Peter Geltenbort, Kevin P. Hickerson, Anthony T. Holley, Takeyasu M. Ito, Kent K. Leung, Chenyu Y. Liu, Deborah J. Morley, Jose D. Ortiz, Robert W. Pattie, John C. Ramsey, Alexander Saunders, Susan J. Seestrom, Eduard I. Sharapov, S. K. Sjue, Judith Wexler, Tanner L. Womack, Albert R. Young, B. A. Zeck, Zhehui Wang

Robert W. Pattie Jr.

Position-sensitive detection of ultracold neutrons (UCNs) is demonstrated using an imaging charge-coupled device (CCD) camera. A spatial resolution less than 15μmhas been achieved, which is equivalent to a UCN energy resolution below 2 pico-electron-volts through the relation δE=m0gδx. Here, the symbols δEδxm0 and gare the energy resolution, the spatial resolution, the neutron rest mass and the gravitational acceleration, respectively. A multilayer surface convertor described previously is used to capture UCNs and then emits visible light for CCD imaging. Particle identification and noise rejection are discussed through the use of light intensity profile analysis. This ...


Measurement Of Spin-Flip Probabilities For Ultracold Neutrons Interacting With Nickel Phosphorus Coated Surfaces, Zhaowen Tang, Evan Robert Adamek, Aaron Brandt, Nathan Brannan Callahan, Steven M. Clayton, Scott Allister Currie, Takeyasu M. Ito, Mark F. Makela, Yasuhiro Masuda, Christopher L. Morris, Robert Wayne Pattie, John Clinton Ramsey, Daniel J. Salvat, Daniel J. Salvat, Alexander Saunders, Albert R. Young Aug 2016

Measurement Of Spin-Flip Probabilities For Ultracold Neutrons Interacting With Nickel Phosphorus Coated Surfaces, Zhaowen Tang, Evan Robert Adamek, Aaron Brandt, Nathan Brannan Callahan, Steven M. Clayton, Scott Allister Currie, Takeyasu M. Ito, Mark F. Makela, Yasuhiro Masuda, Christopher L. Morris, Robert Wayne Pattie, John Clinton Ramsey, Daniel J. Salvat, Daniel J. Salvat, Alexander Saunders, Albert R. Young

Robert W. Pattie Jr.

We report a measurement of the spin-flip probabilities for ultracold neutrons interacting with surfaces coated with nickel phosphorus. For 50 μm thick nickel phosphorus coated on stainless steel, the spin-flip probability per bounce was found to be βNiPonSS=(3.3−5.6+1.8)×10−6. For 50 μm thick nickel phosphorus coated on aluminum, the spin-flip probability per bounce was found to be βNiPonAl=(3.6−5.9+2.1)×10−6. For the copper guide used as reference, the spin flip probability per bounce was found to be βCu=(6.7−2.5+5.0)×10−6. The ...


Neutron-Antineutron Oscillations: Theoretical Status And Experimental Prospects, David G. Phillips, William M. Snow, Kaladi Babu, S. Banerjee, David V. Baxter, Zurab Berezhiani, Marc Bergevin, Satyaki Bhattacharya, Gustaaf Brooijmans, Luis Castellanos, Mark C. Chen, C.E. Coppola, Ramanath K. Cowsik, J.A. Crabtree, Pragya Das, Eric Dees, Aleksander D. Dolgov, Phillip D. Ferguson, Matthew Frost, Tony A. Gabriel, A. Gal, Franz X. Gallmeier, Kenneth S. Ganezer, E. Golubeva, Geoffrey L. Greene, B. Hartfiel, Ayman Hawari, Lawrence H. Heilbronn, Colin D. Johnson, Yu A. Kamyshkov, Boris O. Kerbikov, Masaaki Kitaguchi, B.Z. Kopeliovich, V.B. Kopeliovich, Vadim A. Kuzmin, Chenyu Liu, P. Mcgaughey, M. Mocko, Rabindra N. Mohapatra, Nikolai V. Mokhov, Guenter Muhrer, H.P. Pieter Mumm, Lev B. Okun, Robert W. Pattie, C. Quigg, E. Ramberg, A. Ray, A. Roy, A. Ruggles, U. Sarkar, Andy Saunders, A. P. Serebrovv, H. M. Shimizu, R. Shrock, A. K. Sikdara, Sky Sjue, S. Striganov, L. W. Townsend, R. Tschirhart, A. Vainshtein, R Van Kooten, Z. Wang, A. R. Young Feb 2016

Neutron-Antineutron Oscillations: Theoretical Status And Experimental Prospects, David G. Phillips, William M. Snow, Kaladi Babu, S. Banerjee, David V. Baxter, Zurab Berezhiani, Marc Bergevin, Satyaki Bhattacharya, Gustaaf Brooijmans, Luis Castellanos, Mark C. Chen, C.E. Coppola, Ramanath K. Cowsik, J.A. Crabtree, Pragya Das, Eric Dees, Aleksander D. Dolgov, Phillip D. Ferguson, Matthew Frost, Tony A. Gabriel, A. Gal, Franz X. Gallmeier, Kenneth S. Ganezer, E. Golubeva, Geoffrey L. Greene, B. Hartfiel, Ayman Hawari, Lawrence H. Heilbronn, Colin D. Johnson, Yu A. Kamyshkov, Boris O. Kerbikov, Masaaki Kitaguchi, B.Z. Kopeliovich, V.B. Kopeliovich, Vadim A. Kuzmin, Chenyu Liu, P. Mcgaughey, M. Mocko, Rabindra N. Mohapatra, Nikolai V. Mokhov, Guenter Muhrer, H.P. Pieter Mumm, Lev B. Okun, Robert W. Pattie, C. Quigg, E. Ramberg, A. Ray, A. Roy, A. Ruggles, U. Sarkar, Andy Saunders, A. P. Serebrovv, H. M. Shimizu, R. Shrock, A. K. Sikdara, Sky Sjue, S. Striganov, L. W. Townsend, R. Tschirhart, A. Vainshtein, R Van Kooten, Z. Wang, A. R. Young

Robert W. Pattie Jr.

The observation of neutrons turning into antineutrons would constitute a discovery of fundamental importance for particle physics and cosmology. Observing the n–n̄ transition would show that baryonnumber (B) is violated by two units and that matter containing neutrons is unstable. It would provide a clue to how the matter in our universe might have evolved from the B=0 early universe. If seen at rates observable in foreseeable next-generation experiments, it might well help us understand the observed baryon asymmetry of the universe. A demonstration of the violation of B–L by 2 units would have a profound ...


A Multilayer Surface Detector For Ultracold Neutrons Sep 2015

A Multilayer Surface Detector For Ultracold Neutrons

Robert W. Pattie Jr.

A multilayer surface detector for ultracold neutrons (UCNs) is described. The top 10B layer is exposed to the vacuum chamber and directly captures UCNs. The ZnS:Ag layer beneath the 10B layer is a few microns thick, which is sufficient to detect the charged particles from the 10B(n,α)7Li neutron-capture reaction, while thin enough so that ample light due to α and 7Li escapes for detection by photomultiplier tubes. One-hundred-nm thick 10B layer gives high UCN detection efficiency, as determined by the mean UCN kinetic energy, detector materials and others. Low background ...


Determination Of The Free Neutron Lifetime, J. David Bowman, Leah J. Broussard, Stephen M. Clayton, M. S. Dewey, Nadia Fomin, Keith B. Grammer, G. L. Greene, Paul R. Huffman, Anthony T. Holley, Geoffrey L. Jones, Chenyu Liu, Mark Makela, Michael P. Mendenhall, Charles L. Morris, Jonathan Mulholland, K. M. Nollett, Robert W. Pattie, Seppo Penttila, M. Ramsey-Musolf, Daniel J. Salvat, Andy Saunders, Susan J. Seestrom, William M. Snow, A. Steyerl, F. E. Wietfeldt, Albert R. Young, Andrew T. Yue Oct 2014

Determination Of The Free Neutron Lifetime, J. David Bowman, Leah J. Broussard, Stephen M. Clayton, M. S. Dewey, Nadia Fomin, Keith B. Grammer, G. L. Greene, Paul R. Huffman, Anthony T. Holley, Geoffrey L. Jones, Chenyu Liu, Mark Makela, Michael P. Mendenhall, Charles L. Morris, Jonathan Mulholland, K. M. Nollett, Robert W. Pattie, Seppo Penttila, M. Ramsey-Musolf, Daniel J. Salvat, Andy Saunders, Susan J. Seestrom, William M. Snow, A. Steyerl, F. E. Wietfeldt, Albert R. Young, Andrew T. Yue

Robert W. Pattie Jr.

We present the status of current US experimental efforts to measure the lifetime of the free neutron by the "beam" and "bottle" methods. BBN nucleosynthesis models require accurate measurements with 1 second uncertainties, which are currently feasible. For tests of physics beyond the standard model, future efforts will need to achieve uncertainties well below 1 second. We outline paths achieve both.


Detector Prototype Evaluation At Spallation Neutron Sources, Robert W. Pattie Jr. Jul 2014

Detector Prototype Evaluation At Spallation Neutron Sources, Robert W. Pattie Jr.

Robert W. Pattie Jr.

No abstract provided.


Measurement Of The Half-Life Of The T=1/2 Mirror Decay Of Ne-19 And Its Implication On Physics Beyond The Standard Model, Leah J. Broussard, Henning O. Back, Mitzi S. Boswell, A. S. Crowell, Peter Dendooven, G. S. Giri, Calvin R. Howell, M. F. Kidd, Klaus Jungmann, Wilbert L. Kruithof, A. Mol, Cornelis J. G. Onderwater, Robert W. Pattie Jr., Praveen D. Shidling, M. Sohani, D. J. Van Der Hoek, A. Rogachevskiy, Emil Traykov, Oscar O. Versolato, Lorenz Willmann, Hans W. Wilschut, Andrew T. Young May 2014

Measurement Of The Half-Life Of The T=1/2 Mirror Decay Of Ne-19 And Its Implication On Physics Beyond The Standard Model, Leah J. Broussard, Henning O. Back, Mitzi S. Boswell, A. S. Crowell, Peter Dendooven, G. S. Giri, Calvin R. Howell, M. F. Kidd, Klaus Jungmann, Wilbert L. Kruithof, A. Mol, Cornelis J. G. Onderwater, Robert W. Pattie Jr., Praveen D. Shidling, M. Sohani, D. J. Van Der Hoek, A. Rogachevskiy, Emil Traykov, Oscar O. Versolato, Lorenz Willmann, Hans W. Wilschut, Andrew T. Young

Robert W. Pattie Jr.

The 1 2 þ → 1 2 þ superallowed mixed mirror decay of 19Ne to 19F is excellently suited for high precision studies of the weak interaction. However, there is some disagreement on the value of the half-life. In a new measurement we have determined this quantity to be T1=2 ¼ 17.2832 #1; 0.0051ðstatÞ #1; 0.0066ðsystÞ s, which differs from the previous world average by 3 standard deviations. The impact of this measurement on limits for physics beyond the standard model such as the presence of tensor currents is discussed.


A Method For Measuring Coherent Elastic Neutrino-Nucleus Scattering At A Far Off-Axis High-Energy Neutrino Beam Target Apr 2014

A Method For Measuring Coherent Elastic Neutrino-Nucleus Scattering At A Far Off-Axis High-Energy Neutrino Beam Target

Robert W. Pattie Jr.

We present an experimental method for measuring the process of coherent elastic neutrino-nucleus scattering (CENNS). This method uses a detector situated transverse to a high-energy neutrino beam production target. This detector would be sensitive to the low-energy neutrinos arising from decay-at-rest pions in the target. We discuss the physics motivation for making this measurement and outline the predicted backgrounds and sensitivities using this approach. We report a measurement of neutron backgrounds as found in an off-axis surface location of the Fermilab Booster Neutrino Beam (BNB) target. The results indicate that the Fermilab BNB target is a favorable location for a ...


Characterization Of Large Area, Thick, And Segmented Silicon Detectors For Neutron Β-Decay Experiments, Americo Salas-Bacci, Patrick L. Mcgaughey, Stephan Baeßler, Leah Broussard, Mark F. Makela, J. Mirabal, Robert W. Pattie, Dinko Počanić, Sky K.L. Sjue, Seppo I. Penttila, Wesley S. Wilburn, Albert R. Young, B.A. Zeck, Zhehui Wang Dec 2013

Characterization Of Large Area, Thick, And Segmented Silicon Detectors For Neutron Β-Decay Experiments, Americo Salas-Bacci, Patrick L. Mcgaughey, Stephan Baeßler, Leah Broussard, Mark F. Makela, J. Mirabal, Robert W. Pattie, Dinko Počanić, Sky K.L. Sjue, Seppo I. Penttila, Wesley S. Wilburn, Albert R. Young, B.A. Zeck, Zhehui Wang

Robert W. Pattie Jr.

The “Nab” and “UCNB” collaborations have proposed to measure the correlation parameters in neutron β-decay at Oak Ridge and Los Alamos National Laboratory, using a novel detector design. Two large area, thick, hexagonal-segmented silicon detectors containing 127 pixels per detector will be used to detect the proton and electron from neutron decay. Both silicon detectors are connected by magnetic field lines of a few Tesla field strength, and set on an electrostatic potential, such that protons can be accelerated up to 30 keV in order to be detected. Characteristics of the detector response to low energy conversion electrons and protons ...


The Upscattering Of Ultracold Neutrons From The Polymer (C6h12)N, Eduard I. Sharapov, Christopher L. Morris, Mark Makela, Andy Saunders, Evan R. Adamek, Leah J. Broussard, Chris B. Cude-Woods, Deion E. Fellers, Peter Geltenbort, Monika Hartl, Siraj I. Hasan, Kevin P. Hickerson, Gary E. Hogan, Anthony T. Holley, C. M. Lavelle, Chen-Yu Liu, Michael P. Mendenhall, Jose Ortiz, Robert W. Pattie, David G. Phillips, John Ramsey, Daniel J. Salvat, Susan J. Seestrom, Erik Shaw, Sky Sjue, Walter E. Sondheim, Brittany Vorndick, Zhehui Wang, Tanner L. Womack, Andrew R. Young, B. A. Zeck Dec 2013

The Upscattering Of Ultracold Neutrons From The Polymer (C6h12)N, Eduard I. Sharapov, Christopher L. Morris, Mark Makela, Andy Saunders, Evan R. Adamek, Leah J. Broussard, Chris B. Cude-Woods, Deion E. Fellers, Peter Geltenbort, Monika Hartl, Siraj I. Hasan, Kevin P. Hickerson, Gary E. Hogan, Anthony T. Holley, C. M. Lavelle, Chen-Yu Liu, Michael P. Mendenhall, Jose Ortiz, Robert W. Pattie, David G. Phillips, John Ramsey, Daniel J. Salvat, Susan J. Seestrom, Erik Shaw, Sky Sjue, Walter E. Sondheim, Brittany Vorndick, Zhehui Wang, Tanner L. Womack, Andrew R. Young, B. A. Zeck

Robert W. Pattie Jr.

It is generally accepted that the main cause of ultracold neutron (UCN) losses in storage traps is upscattering to the thermal energy range by hydrogen adsorbed on the surface of the trap walls. However, the data on which this conclusion is based are poor and contradictory. Here we report a measurement, performed at the Los Alamos National Laboratory UCN source, of the average energy of the flux of upscattered neutrons after the interaction of UCN with hydrogen bound in the semicrystalline polymer PMP (trade name TPX), [C6H12]n. Our analysis, performed with the mcnp code which applies ...


Limits On Tensor Coupling From Neutron Β Decay, Robert W. Pattie, Kevin P. Hickerson, Andrew R. Young Oct 2013

Limits On Tensor Coupling From Neutron Β Decay, Robert W. Pattie, Kevin P. Hickerson, Andrew R. Young

Robert W. Pattie Jr.

Limits on the tensor couplings generating a Fierz interference term b in mixed Gamow-Teller Fermi decays can be derived by combining data from measurements of angular correlation parameters in neutron decay, the neutron lifetime, and GV=GFVud as extracted from measurements of the Ftvalues from the 0+→0+ superallowed decay data set. These limits are derived by comparing the neutron β-decay rate as predicted in the standard model with the measured decay rate while allowing for the existence of beyond the standard model (BSM) couplings. We analyze limits derived from the electron-neutrino asymmetry ...


Measurements Of Ultracold Neutron Upscattering And Absorption In Polyethylene And Vanadium, Eduard I. Sharapov, Charles L. Morris, Mark Makela, Andy Saunders, Evan R. Adamek, Yelena Bagdasarova, Leah J. Broussard, Chris Cude-Woods, Deon E. Fellers, Peter Geltenbort, Siraj I. Hasan, Kevin P. Hickerson, Gary Hogan, Anthony T. Holley, Chen-Yu Liu, Michael P. Mendenhall, Jose Ortiz, Robert W. Pattie Jr., David G. Phillips, John Ramsey, D. J. Salvat, Susan J. Seestrom, E. Shaw, Sky Sjue, Walter E. Sondheim, Brittany Vorndick, Zhehui Wang, Tanner L. Womack, Andrew R. Young, B. A. Zeck Sep 2013

Measurements Of Ultracold Neutron Upscattering And Absorption In Polyethylene And Vanadium, Eduard I. Sharapov, Charles L. Morris, Mark Makela, Andy Saunders, Evan R. Adamek, Yelena Bagdasarova, Leah J. Broussard, Chris Cude-Woods, Deon E. Fellers, Peter Geltenbort, Siraj I. Hasan, Kevin P. Hickerson, Gary Hogan, Anthony T. Holley, Chen-Yu Liu, Michael P. Mendenhall, Jose Ortiz, Robert W. Pattie Jr., David G. Phillips, John Ramsey, D. J. Salvat, Susan J. Seestrom, E. Shaw, Sky Sjue, Walter E. Sondheim, Brittany Vorndick, Zhehui Wang, Tanner L. Womack, Andrew R. Young, B. A. Zeck

Robert W. Pattie Jr.

The study of neutron cross sections for elements used as efficient “absorbers” of ultracold neutrons (UCN) is crucial for many precision experiments in nuclear and particle physics, cosmology and gravity. In this context, “absorption” includes both the capture and upscattering of neutrons to the energies above the UCN energy region. The available data, especially for hydrogen, do not agree between themselves or with the theory. In this report we describe measurements performed at the Los Alamos National Laboratory UCN facility of the UCN upscattering cross sections for vanadium and for hydrogen in CH2 using simultaneous measurements of the radiative ...


Project X: Physics Opportunities, Andreas S. Kronfeld, Robert S. Tschirhart, Usama Al-Binni, Wolfgang Altmannshofer, Charles Ankenbrandt, Kaladi Babu, Sunanda Banerjee, Matthew Bass, Brian Batell, David V. Baxter, Zurab Berezhiani, Marc Bergevin, Robert Bernstein, Sudeb Bhattacharya, Mary Bishai, Thomas Blum, S. Alex Bogacz, Stephen J. Brice, Joachim Brod, Alan Bross, Michael Buchoff, Thomas W. Burgess, Marcela Carena, Luis A. Castellanos, Subhasis Chattopadhyay, Mu-Chun Chen, Daniel Cherdack, Norman H. Christ, Tim Chupp, Vincenzo Cirigliano, Pilar Coloma, Christopher E. Coppola, Ramanath Cowsik, J. Allen Crabtree, André De Gouvêa, Jean-Pierre Delahaye, Dmitri Denisov, Patrick Deniverville, Ranjan Dharmapalan, Alexander Dolgov, Georgi Dvali, Estia Eichten, Jürgen Engelfried, Phillip D. Ferguson, Tony Gabriel, Avraham Gal, Franz Gallmeier, Kenneth S. Ganezer, Susan Gardner Jul 2013

Project X: Physics Opportunities, Andreas S. Kronfeld, Robert S. Tschirhart, Usama Al-Binni, Wolfgang Altmannshofer, Charles Ankenbrandt, Kaladi Babu, Sunanda Banerjee, Matthew Bass, Brian Batell, David V. Baxter, Zurab Berezhiani, Marc Bergevin, Robert Bernstein, Sudeb Bhattacharya, Mary Bishai, Thomas Blum, S. Alex Bogacz, Stephen J. Brice, Joachim Brod, Alan Bross, Michael Buchoff, Thomas W. Burgess, Marcela Carena, Luis A. Castellanos, Subhasis Chattopadhyay, Mu-Chun Chen, Daniel Cherdack, Norman H. Christ, Tim Chupp, Vincenzo Cirigliano, Pilar Coloma, Christopher E. Coppola, Ramanath Cowsik, J. Allen Crabtree, André De Gouvêa, Jean-Pierre Delahaye, Dmitri Denisov, Patrick Deniverville, Ranjan Dharmapalan, Alexander Dolgov, Georgi Dvali, Estia Eichten, Jürgen Engelfried, Phillip D. Ferguson, Tony Gabriel, Avraham Gal, Franz Gallmeier, Kenneth S. Ganezer, Susan Gardner

Robert W. Pattie Jr.

Part 2 of "Project X: Accelerator Reference Design, Physics Opportunities, Broader Impacts". In this Part, we outline the particle-physics program that can be achieved with Project X, a staged superconducting linac for intensity-frontier particle physics. Topics include neutrino physics, kaon physics, muon physics, electric dipole moments, neutron-antineutron oscillations, new light particles, hadron structure, hadron spectroscopy, and lattice-QCD calculations. Part 1 is available as arXiv:1306.5022 [physics.acc-ph] and Part 3 is available as arXiv:1306.5024 [physics.acc-ph].


Precision Measurement Of The Neutron Beta-Decay Asymmetry, Michael P. Mendenhall, Robert W. Pattie, Yelena Bagdasarova, David B. Berguno, Leah J. Broussard, Richard Carr, Scott Currie, Xinjian Ding, Bradley W. Filippone, Alejandro Garcia, Peter Geltenbort, Kevin P. Hickerson, J. Todd Hoagland, Anthony T. Holley, Ran Hong, Takeyasu M. Ito, Andreas Knecht, Chenyu Liu, J. L. Liu, Mark Makela, Russell R. Mammei, J. W. Martin, Dan Melconian, Spencer D. Moore, Christopher L. Morris, Margaret L. Pitt, Blakely Plaster, John C. Ramsey, Roger Rios, Andy Saunders, Susan J. Seestrom, Eduard I. Sharapov, Walter E. Sondheim, E. Tatar, Robert B. Vogelaar, Brittany Vorndick, Christopher Wrede, Andrew R. Young, B. A. Zeck Mar 2013

Precision Measurement Of The Neutron Beta-Decay Asymmetry, Michael P. Mendenhall, Robert W. Pattie, Yelena Bagdasarova, David B. Berguno, Leah J. Broussard, Richard Carr, Scott Currie, Xinjian Ding, Bradley W. Filippone, Alejandro Garcia, Peter Geltenbort, Kevin P. Hickerson, J. Todd Hoagland, Anthony T. Holley, Ran Hong, Takeyasu M. Ito, Andreas Knecht, Chenyu Liu, J. L. Liu, Mark Makela, Russell R. Mammei, J. W. Martin, Dan Melconian, Spencer D. Moore, Christopher L. Morris, Margaret L. Pitt, Blakely Plaster, John C. Ramsey, Roger Rios, Andy Saunders, Susan J. Seestrom, Eduard I. Sharapov, Walter E. Sondheim, E. Tatar, Robert B. Vogelaar, Brittany Vorndick, Christopher Wrede, Andrew R. Young, B. A. Zeck

Robert W. Pattie Jr.

A new measurement of the neutron β-decay asymmetry A0 has been carried out by the UCNA collaboration using polarized ultracold neutrons (UCN) from the solid deuterium UCN source at the Los Alamos Neutron Science Center (LANSCE). Improvements in the experiment have led to reductions in both statistical and systematic uncertainties leading to A0 = −0.11954(55)stat.(98)syst., corresponding to the ratio of axial-vector to vector coupling λ ≡ gA/gV = −1.2756(30). 


Performance Of The Los Alamos National Laboratory Spallation-Driven Solid-Deuterium Ultra-Cold Neutron Source, Andrew Saunders, Mark Makela, Yelena Bagdasarova, Henning O. Back, J. Boissevain, Leah J. Broussard, Thomas J. Bowles, R. Carr, Scott A. Currie, Bradley Filippone, A. García, Peter Geltenbort, Kevin P. Hickerson, R. E. Hill, J. Todd Hoagland, S. Hoedl, Anthony T. Holley, Gary E. Hogan, Takeyasu M. Ito, Steve Lamoreaux, Chen-Yu Liu, J. Liu, Russell R. Mammei, J. Martin, Dan Melconian, Michael P. Mendenhall, Charles L. Morris, R. N. Mortensen, Robert W. Pattie, Margaret Pitt, Bradley Plaster, John Ramsey, R. Rios, A. Sallaska, Susan J. Seestrom, E. I. Sharapov, Sky Sjue, Walter E. Sondheim, W. Teasdale, Andrew R. Young, Brittany Vorndick, Robert B. Vogelaar, Zhehui Wang, Yanping Xu Dec 2012

Performance Of The Los Alamos National Laboratory Spallation-Driven Solid-Deuterium Ultra-Cold Neutron Source, Andrew Saunders, Mark Makela, Yelena Bagdasarova, Henning O. Back, J. Boissevain, Leah J. Broussard, Thomas J. Bowles, R. Carr, Scott A. Currie, Bradley Filippone, A. García, Peter Geltenbort, Kevin P. Hickerson, R. E. Hill, J. Todd Hoagland, S. Hoedl, Anthony T. Holley, Gary E. Hogan, Takeyasu M. Ito, Steve Lamoreaux, Chen-Yu Liu, J. Liu, Russell R. Mammei, J. Martin, Dan Melconian, Michael P. Mendenhall, Charles L. Morris, R. N. Mortensen, Robert W. Pattie, Margaret Pitt, Bradley Plaster, John Ramsey, R. Rios, A. Sallaska, Susan J. Seestrom, E. I. Sharapov, Sky Sjue, Walter E. Sondheim, W. Teasdale, Andrew R. Young, Brittany Vorndick, Robert B. Vogelaar, Zhehui Wang, Yanping Xu

Robert W. Pattie Jr.

In this paper, we describe the performance of the Los Alamos spallation-driven solid-deuterium ultracold neutron (UCN) source. Measurements of the cold neutron flux, the very low energy neutron production rate, and the UCN rates and density at the exit from the biological shield are presented and compared to Monte Carlo predictions. The cold neutron rates compare well with predictions from the Monte Carlo code MCNPX and the UCN rates agree with our custom UCN Monte Carlo code. The source is shown to perform as modeled. The maximum delivered UCN density at the exit from the biological shield is 52(9 ...