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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 results on the nickel phosphorus-coated surfaces may be interpreted as upper limits, yielding βNiPonSS<6.2×10−6 (90% C.L.) and βNiPonAl<7.0×10−6 (90% C.L.) for 50 μm thick …

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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, including …

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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 …

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Measurement Of The Neutron -Asymmetry Parameter A0 With Ultracold Neutrons, Bradley Plaster, R. Rios, Thomas J. Bowles, Leah J. Broussard, Richard Carr, Steven Clayton, Scott Currie, Bradley W. Filippone, Peter Geltenbort, Kevin P. Hickerson, J. Todd Hoagland, Gary E. Hogan, B. Hona, Anthoney T. Holley, Takeyasu M. Ito, Chenyu Liu, Jingyang Liu, Mark Makela, J. W. Martin, Daniel Melconian, Michael P. Mendenhall, Charles L. Morris, R. Mortensen, Robert W. Pattie, Margaret L. Pitt, John C. Ramsey, R. Russell, Andy Saunders, R. Schmid, Susan J. Seestrom, Sky Sjue, Walter E. Sondheim, E. Tatar, B. Tipton, Robert B. Vogelaar, Brittany Vorndick, Christopher Wrede, Y. P. Xu, H. Yan, Andrew R. Young, J. Yuan

Robert W. Pattie Jr.

We present a detailed report of a measurement of the neutron β-asymmetry parameter A0, the parity-violating angular correlation between the neutron spin and the decay electron momentum, performed with polarized ultracold neutrons (UCN). UCN were extracted from a pulsed spallation solid deuterium source and polarized via transport through a 7-T magnetic field. The polarized UCN were then transported through an adiabatic-fast-passage spin-flipper field region, prior to storage in a cylindrical decay volume situated within a 1-T 2 × 2π solenoidal spectrometer. The asymmetry was extracted from measurements of the decay electrons in multiwire proportional chamber and plastic scintillator detector packages …

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Determination Of The Axial-Vector Weak Coupling Constant With Ultracold Neutrons., J. Liu, Michael P. Mendenhall, Anthony T. Holley, Henning O. Back, Thomas J. Bowles, Leah J. Broussard, Richard Carr, Stephen Clayton, Scott Currie, Bradley W. Filippone, A. Garcı́A, Peter Geltenbort, Kevin P. Hickerson, J. Todd Hoagland, Gary E. Hogan, B. Hona, Takeyasu M. Ito, Chenyu Liu, Mark Makela, Russell R. Mammei, J.W. Martin, Daneil Melconian, Charles L. Morris, Robert W. Pattie, A. Pérez Galván, Margaret L. Pitt, Bradley Plaster, John C. Ramsey, R. Rios, R. Russell, Andy Saunders, Susan J. Seestrom, Walter E. Sondheim, E. Tatar, Robert B. Vogelaar, Brittany Vorndick, Christopher Wrede, H. Yan, Albert R. Young

Robert W. Pattie Jr.

A precise measurement of the neutron decay β asymmetry A0 has been carried out using polarized ultracold neutrons from the pulsed spallation ultracold neutron source at the Los Alamos Neutron Science Center. Combining data obtained in 2008 and 2009, we report A0=−0.11966±0.00089+0.00123−0.00140, from which we determine the ratio of the axial-vector to vector weak coupling of the nucleon gA/gV=−1.27590+0.00409−0.00445.

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First Measurement Of The Neutron Beta Asymmetry With Ultracold Neutrons, Robert W. Pattie, J. Anaya, Henning O. Back, J. G. Boissevain, Thomas J. Bowles, Leah J. Broussard, Richard Carr, D. J. Clark, Scott Currie, S. Du, Bradley W. Filippone, Peter Geltenbort, A. García, Ayman I. Hawari, Kevin P. Hickerson, R. Hill, M. Hino, S. A. Hoedl, Gary E. Hogan, Anthony T. Holley, Takeyasu M. Ito, T. Kawai, K. Kirch, S. Kitagaki, Steve K. Lamoreaux, Chenyu Liu, Jingyang Liu, Mark Makela, Russell R. Mammei, J. W. Martin, Daniel Melconian, N. Meier, Michael P. Mendenhall, Charles L. Morris, R. Mortensen, A. Pichlmaier, Margaret L. Pitt, Blakely Plaster, John C. Ramsey, Roger Rios, Konstantin Sabourov, A. L. Sallaska, Alexander Saunders, R. Schmid, Susan J. Seestrom, C. Servicky, Sky K. L. Sjue, D. Smith, Walter E. Sondheim, E. Tatar, W. Teasdale, Christopher R. Terai, B. Tipton, M. Utsuro, R. Bruce Vogelaar, Bernard Wehring, Y. P. Xu, Andrew R. Young, J. Yuan

Robert W. Pattie Jr.

We report the first measurement of an angular correlation parameter in neutron #1; decay using polarized ultracold neutrons (UCN). We utilize UCN with energies below about 200 neV, which we guide and store for #1;30 s in a Cu decay volume. The interaction of the neutron magnetic dipole moment with a static 7 T field external to the decay volume provides a 420 neV potential energy barrier to the spin state parallel to the field, polarizing the UCN before they pass through an adiabatic fast passage spin flipper and enter a decay volume, situated within a 1 T field in …

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Robert W. Pattie Jr.

A Multilayer Surface Detector For Ultracold Neutrons

Robert W. Pattie Jr.

Robert W. Pattie Jr.

Robert W. Pattie Jr.

Robert W. Pattie Jr.

Robert W. Pattie Jr.