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Search Publications by: Jeffrey S. Nico (Fed)

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Displaying 26 - 50 of 159

Nonproportionality in the scintillation light yield of bismuth germanate

November 11, 2014
Author(s)
Thomas R. Gentile, M J. Bales, H Breuer, T E. Chupp, Kevin J. Coakley, R L. Cooper, Jeffrey S. Nico, B. O'Neill
We present measurements of nonproportionality in the scintillation light yield of bismuth germanate (BGO) for gamma-rays with energies between 6 keV and 662 keV. The scintillation light was read out by avalanche photodiodes (APDs) with both the BGO

Fast Neutron Detection with a Segmented Spectrometer

November 3, 2014
Author(s)
Jeffrey S. Nico, T J. Langford, Christopher D. Bass, H Breuer, Craig Heimbach, D. K. Erwin
A fast neutron spectrometer consisting of segmented plastic scintillator and He-3 proportional counters was constructed for the measurement of neutrons in the energy range 1 MeV to 200 MeV. We discuss its design, principles of operation, and the method of

International Key Comparison of Neutron Fluence Measurements in Monoenergetic Neutron Fields – CCRI(III)-K11

November 3, 2014
Author(s)
Maynard S. Dewey, V. Gressier, A. C. Bonaldi, David M. Gilliam, H. Harano, A. Masuda, T Matsumoto, N. Moiseev, Jeffrey S. Nico, R. Notle, S. Oberstedt, N. J. Roberts, S. Rottger, D. J. Thomas
To ensure the validity of their national standards, National Metrology Institutes, NMIs, participate regularly in international comparisons. In the area of neutron metrology, Section III of the Consultative Committee for Ionizing Radiation is in charge of

Significant disparity in base and sugar damage in DNA by neutron and electron irradiation

July 1, 2014
Author(s)
Pawel Jaruga, Jeffrey S. Nico, Lisa R. Karam, Olga Timofeeva, William Blakely, M Miral Dizdar, D Pang
In this study a comparison of the effects of high-LET neutrons with low-LET electrons on irradiation of aqueous DNA solutions was investigated to characterize for potential neutron signatures on DNA damage induction. Ionizing radiations generate numerous

Improved Determination of the Neutron Lifetime

December 2, 2013
Author(s)
Jeffrey S. Nico, A. T. Yue, Maynard S. Dewey, David M. Gilliam, G L. Greene, A. Laptev, William M. Snow, F. E. Wiefeldt
The most precise determination of the neutron lifetime using the beam method was completed in 2005 and reported a result of tau_n = (886.3 ± 1.2 [stat] ± 3.2 [sys]) s. The dominant uncertainties were attributed to the absolute determination of the fluence

Event Identification in He-3 Proportional Counters Using Risetime Discrimination

April 2, 2013
Author(s)
Jeffrey S. Nico, T J. Langford, Christopher D. Bass, E J. Beise, D. K. Erwin, Craig Heimbach
We present a straightforward method for particle identification and background rejection in He-3 proportional counters for use in neutron detection. By measuring the risetime and pulse height of the preamplifier signals, one may define a region in the

Search for a T-odd, P-even Triple Correlation in Neutron Decay

September 14, 2012
Author(s)
Jeffrey S. Nico, T E. Chupp, K P. Coulter, R L. Cooper, S. J. Freeman, B. K. Fujikawa, A. Garcia, Gordon L. Jones, Hans P. Mumm, Alan K. Thompson, C A. Trull, F. E. Wiefeldt, J. F. Wilkerson
Time-reversal-invariance (T) violation, or equivalently, assuming charge-conjugation-parity-time-reversal (CPT) invariance, CP violation may explain the observed cosmological baryon asymmetry as well as signal physics beyond the Standard Model. In the

A New Limit on Time-Reversal Violation in Beta Decay

September 2, 2012
Author(s)
Hans P. Mumm, T E. Chupp, K P. Coulter, R L. Cooper, S J. Freedman, B. K. Fujikawa, A. Garcia, Gordon L. Jones, Jeffrey S. Nico, Alan K. Thompson, C A. Trull, J. F. Wilkerson, F. E. Wiefeldt
We report the results of an improved determination of the triple correlation DP • (p_e × p_v) that can be used to limit possible time-reversal invariance in the beta decay of polarized neutrons and constrain extensions to the Standard Model. Our result is

A gamma and X-ray dector for cryogenic, high magnetic field applications

July 13, 2012
Author(s)
Thomas R. Gentile, R L. Cooper, R. Alarcon, M J. Bales, E J. Beise, H Breuer, J. Byrne, T E. Chupp, Kevin J. Coakley, Maynard S. Dewey, Changbo Fu, Hans P. Mumm, Jeffrey S. Nico, B. O'Neill, K. Pulliam, Alan Keith Thompson, F E. Wietfeldt
As part of an experiment to measure the spectrum of photons emitted in beta-decay of the free neu- tron, we developed and operated a detector consisting of 12 bismuth germanate (BGO) crystals coupled to avalanche photodiodes (APDs). The detector was

Magnetic field effects on large area avalanche photodiodes at cryogenic temperatures

August 30, 2011
Author(s)
Thomas R. Gentile, C. D. Bass, Jeffrey S. Nico, H Breuer, R Farrell
We present results for detection of X-rays by large area avalanche photodiodes (APDs) in strong magnetic fields and at cryogenic temperatures. Whereas at room temperature we observe essentially no effects on the response, at cryogenic temperature we

Fast Neutron Detection with Li-6-loaded Liquid Scintillator

April 12, 2011
Author(s)
David M. Gilliam, B Fisher, J N. Abdurashitov, Kevin Coakley, V N. Gavrin, Jeffrey S. Nico, A A. Shikhin, Alan Keith Thompson, Dominic F. Vecchia, V E. Yants
We report on the development of a fast neutron detector using a liquid scintillator doped with enriched 6Li. The lithium was introduced in the form of an aqueous LiCl micro-emulsion with a di-isopropylnaphthalene based liquid scintillator. A 6Li

An Upper Bound on Parity Violating Neutron Spin Rotation in He-4

January 31, 2011
Author(s)
Jeffrey S. Nico, William M. Snow, Christopher D. Bass, Tiffany D. Bass, B. E. Crawford, K. F. Gan, B R. Heckel, D Lou, D M. Markoff, A M. Micherdzinska, Hans P. Mumm, A. K. Opper, M Sarsour, E I. Sharapov, H E. Swanson, S. C. Walbridge, V Zhumabekova
We report an upper bound on parity violating neutron spin rotation in He-4. This experiment is the most sensitive search for neutron weak optical activity yet performed. Our result for the neutron spin rotation angle per unit length in He-4 is dphi/dz = (
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