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Physics

Nuclear physics

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Displaying 126 - 150 of 245

The 12C(n,2n)11C Cross Section from Threshold to 26.5 MeV

February 20, 2018
Author(s)
Ryan P. Fitzgerald, M Yuly, T Eckert, G Hartshaw, S. J. Padalino, D. N. Polsin, M. Russ, A. T. Simone, C R. Brune, T N. Massey, C. E. Parker, T. C. Sangster, S P. Regan
The 12C(n, 2n)11C cross section was measured from just below threshold to 26.5 MeV using the pelletron accelerator at Ohio University. Monoenergetic neutrons, produced via the 3H(d,n)4He reaction, were allowed to strike targets of polyethylene and graphite

Increased interference fringe visibility from the post fabrication heat treatment of a perfect crystal silicon neutron interferometer

February 8, 2018
Author(s)
Michael G. Huber, Muhammad D. Arif, Thomas H. Gnaupel-Herold, Michelle E. Jamer, Ben Heacock, David G. Cory, R. Haun, Joachim Nsofini, Dimitry A. Pushin, Ivar Taminiau, A.R. Young
We find that annealing a previously chemically etched interferometer at 800 °C dramatically increased the interference fringe visibility from 23 % to 90 %. The Bragg plane misalignments were also measured before and after annealing using neutron rocking

Activity measurements of the radionuclides 18F and 64Cu for the NIST, USA in the ongoing comparisons BIPM.RI(II)-K4.F-18 and BIPM.RI(II)-K4.Cu-64

January 1, 2018
Author(s)
Denis E. Bergeron, Jeffrey T. Cessna, Ryan P. Fitzgerald, Leticia S. Pibida, Brian E. Zimmerman, Carine Michotte, Manuel Nonis, Andrew Fenwick, Kelly Ferreira, John Keightley
In 2016, comparisons of activity measurements of 18F and 64Cu using the Transfer Instrument of the International Reference System (SIRTI) took place at the National Institute of Standards and Technology (NIST, USA). This is the first SIRTI comparison for

Natural Uranium Radioactivity Solution Standard: SRM 4321d

December 27, 2017
Author(s)
Ronald Colle, Lizbeth Laureano-Perez, Svetlana Nour, Jerome J. LaRosa, Brian E. Zimmerman, Leticia S. Pibida, Denis E. Bergeron
A new natural uranium solution standard has been produced and will be disseminated by the National Institute of Standards and Technology (NIST) as Standard Reference Material 4321d. The standard is certified for the massic activities of 234U, 235U, and

Two determinations of the Ge-68 half-life

October 19, 2017
Author(s)
Denis E. Bergeron, Jeffrey T. Cessna, Brian E. Zimmerman
In nuclear medicine, 68Ge is used to generate 68Ga for imaging by positron emission tomography (PET) and sealed sources containing 68Ge/68Ga in equilibrium have been adopted as long-lived calibration surrogates for the more common PET nuclide, 18F. We

Monte Carlo modelling of live-timed anticoincidence (LTAC) counting for Cu-64

September 20, 2017
Author(s)
Denis E. Bergeron, Ryan P. Fitzgerald
The radionuclide copper-64 is a promising candidate for nuclear medicine, but its complex decay creates challenges in the primary standardization of its activity. Monte Carlo simulations of live timed anticoincidence (LTAC) counting of 64Cu were used to

Phase stability and lithium loading capacity in a liquid scintillation cocktail

August 2, 2017
Author(s)
Denis E. Bergeron, Mark A. Tyra, Hans P. Mumm
Liquid scintillation cocktails loaded with neutron capture agents such as 6Li are used in both neutron and neutrino detectors. For detectors designed to operate over extended timespans, long-term stability can be a concern. We demonstrate the

aCORN: an experiment to measure the electron-antineutrino correlation coefficient in free neutron decay

August 1, 2017
Author(s)
Maynard S. Dewey, Fred B. Bateman, Wangchun Chen, Thomas R. Gentile, Md. T. Hassan, Michael P. Mendenhall, Jeffrey S. Nico, Brian Collett, Jim Byrne, William Byron, Guillaume Darius, Christina DeAngelis, Gordon L. Jones, Alexander Komives, Alexander Laptev, George Noid, Hyeonseo Park, Ed Stephenson, I Stern, K Stockton, Bob Trull, Fred Wietfeldt, B G. Yerozolimsky
We describe an apparatus used to measure the electron-neutrino angular correlation coefficient, a, in free neutron decay. The apparatus employs a novel measurement technique in which the angular correlation is converted into a proton time-of-flight

Noise Refocusing in a Five-blade Neutron Interferometer

August 1, 2017
Author(s)
Michael G. Huber, Muhammad D. Arif, Dimitry A. Pushin, David G. Cory, Dusan Sarenac, Joachim Nsofini, Kamyar Ghofrani
We provide a quantum information description of a proposed five-blade neutron interferometer geometry and show that it is robust against low-frequency mechanical vibrations and dephasing due to the dynamical phase. The extent to which the dynamical phase

Precision measurement of the radiative beta decay of the free neutron

June 30, 2017
Author(s)
Christopher D. Bass, Maynard S. Dewey, Thomas R. Gentile, Hans Pieter Mumm, Alan Keith Thompson, M J. Bales, R. Alarcon, E J. Beise, H Breuer, Jim Byrne, T E. Chupp, Kevin Coakley, R L. Cooper, B. O'Neill, F E. Wietfeldt
The theory of quantum electrodynamics predicts that a continuous spectrum of photons is emitted in the beta decay of the free neutron in addition to a proton, an electron, and an antineutrino. We report the first precision test of the shape of the photon

A Backscatter-Suppressed Beta Spectrometer

June 16, 2017
Author(s)
Maynard S. Dewey, Taufique Hassan, Fred B. Bateman, Brian Collett, Guillaume Darius, Christina DeAngelis, Gordon L. Jones, Alexander Komives, Alexander Laptev, Michael Mendenhall, Jeffrey S. Nico, George Noid, Ed Stephenson, Fred Wietfeldt, Isaac Stern, Bob Trull
Backscatter of electrons from a beta spectrometer, with incomplete energy deposition, can lead to undesirable effects in many types of experiments. We present and discuss the design and operation of a backscatter-suppressed beta spectrometer that was

Decoupling of a Neutron Interferometer from Temperature Gradients

December 16, 2016
Author(s)
Michael G. Huber, Muhammad D. Arif, P. Saggu, T. Mineeva, David Cory, Robert Haun, Ben Heacock, K Li, J. Nsofini, D. Sarenac, Chandra Shahi, V Skavysh, Mike Snow, S. Werner, A.R. Young, Dmitry Pushin
Neutron interferometry enables precision measurements that are typically operated within elaborate, multi-layered facilities which provide substantial shielding from environmental noise. These facilities are necessary to maintain the coherence requirements