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Physics

Nuclear physics

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Displaying 76 - 100 of 136

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

The PROSPECT Physics Program

October 17, 2016
Author(s)
Hans P. Mumm, Michael P. Mendenhall
The Precision Reactor Oscillation and Spectrum Experiment, PROSPECT, is designed to make a precise measurement of the antineutrino spectrum from a highly-enriched uranium reactor and probe eV-scale sterile neutrinos by searching for neutrino oscillations

First application of superconducting transition-edge-sensor microcalorimeters to hadronic-atom x-ray spectroscopy

September 30, 2016
Author(s)
Douglas Bennett, W.Bertrand (Randy) Doriese, Joseph Fowler, Johnathon Gard, James P. Hays-Wehle, Gene C. Hilton, Carl D. Reintsema, Daniel Swetz, Joel Ullom
High-resolution pionic-atom x-ray spectroscopy was performed with an x-ray spectrometer based on a 240-pixel array of superconducting transition-edge-sensor (TES)microcalorimeters at the πM1 beam line of the Paul Scherrer Institute. The pionic-carbon 4 → 3

Evidence against solar influence on nuclear decay constants

August 24, 2016
Author(s)
Denis E. Bergeron, Ryan P. Fitzgerald, Leticia S. Pibida, Stefaan Pomme
The exponential decay of radionuclides as a function of time is a cornerstone of nuclear physics and radionuclide metrology. Decay constants for spontaneous radioactive decay are considered invariable in time and space. This convenient trait allows

A 3He beam stop for minimizing gamma-ray and fast-neutron background

August 6, 2016
Author(s)
Danyal J. Turkoglu, Robert G. Downing, Wangchun Chen, Dagistan Sahin, Jeremy C. Cook
Prompt gamma-ray activation analysis facilities with high neutron currents (≥109 s-1) generate triton-induced fast neutrons from 6Li-loaded collimators and beam stops at rates that soon damage gamma-ray detectors. We develop an alternative beam stop design

Precision measurement of the radiative beta decay of the free neutron

June 14, 2016
Author(s)
Jeffrey S. Nico, Kevin J. Coakley, Maynard S. Dewey, Thomas R. Gentile, Hans P. Mumm, Alan Keith Thompson, M J. Bales, R. Alarcon, C. D. Bass, E J. Beise, H Breuer, Jim Byrne, R L. Cooper, B. O'Neill, F E. Wietfeldt, T E. Chupp
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

Invited Article: MiniTimeCube

June 13, 2016
Author(s)
Hans P. Mumm
We present the development of the miniTimeCube (mTC), the world’s smallest neutrino detector. The mTC is a multipurpose detector, aiming to detect not only neutrinos but also fast/thermal neutrons and gammas. Potential applications include the

Micellar phase boundaries under the influence of ethyl alcohol

May 16, 2016
Author(s)
Denis E. Bergeron
The Compton spectrum quenching technique is used to monitor the effect of ethyl alcohol (EtOH) additions on phase boundaries in two systems. In toluenic solutions of the nonionic surfactant, Triton X-100, EtOH shifts the boundary separating the first clear

Comparison of C-14 liquid scintillation counting at NIST and NRC Canada

March 1, 2016
Author(s)
Denis E. Bergeron, Raphael Galea, Lizbeth Laureano-Perez, Brian E. Zimmerman
An informal bilateral comparison of 14C liquid scintillation (LS) counting at the National Research Council of Canada (NRC) and the National Institute of Standards and Technology (NIST) has been completed. Two solutions, one containing 14C-labeled sodium

Absolute Energy Calibration of X-ray TESs with 0.04 eV Uncertainty at 6.4 keV in a Hadron-Beam Environment

January 19, 2016
Author(s)
Hideyuki Tatsuno, William B. Doriese, Douglas A. Bennett, Catalina Curceanu, Joseph W. Fowler, Johnathon D. Gard, Fredrick P. Gustafsson, Tadashi Hashimoto, Ryugo S. Hayano, James P. Hays-Wehle, Gene C. Hilton, Mihail Iliescu, Shigeru Ishimoto, Kenta Itahashi, Masashiko Iwasaki, Keisuke Kuwabara, Yue Ma, Johann Marton, Hirofumi Noda, Galen C. O'Neil, Shinji Okada, Haruhiko Outa, Carl D. Reintsema, Masaharu Sato, Daniel R. Schmidt, Hexi Shi, Ken Suzuki, Takatoshi Suzuki, Jens Uhlig, Joel N. Ullom, Eberhard Widmann, Shinya Yamada, Johann Zmeskal, Daniel S. Swetz
A performance evaluation of superconducting transition-edge sensors (TESs) in the environment of a pion beam line at a particle accelerator is presented. Averaged across the 209 functioning sensors in the array, the achieved energy resolution is 5.2 eV

Background Radiation Measurements at High Power Research Reactors

January 11, 2016
Author(s)
Hans P. Mumm
Research reactors typically host a wide range of activities that make use of the intense neutron fluxes generated at these facilities. Recent interest in performing measurements with relatively low event rates, e.g. reactor antineutrino detection, at these
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