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1. Fast Neutron Detection with a Segmented Spectrometer
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 meth ...
2. International Key Comparison of Neutron Fluence Measurements in Monoenergetic Neutron Fields ‹ CCRI(III)-K11
Maynard S Dewey, V. Gressier, A. C. Bonaldi, David McLarty 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 char ...
3. Significant disparity in base and sugar damage in DNA by neutron and electron irradiation
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 ...
4. Improved Determination of the Neutron Lifetime
Jeffrey S Nico, A. T. Yue, Maynard S Dewey, David McLarty Gilliam, G L. Greene, A. Laptev, W 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 f ...
5. Event Identification in He-3 Proportional Counters Using Risetime Discrimination
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 th ...
6. Characterization of a 6Li-loaded liquid organic scintillator for fast neutron spectrometry and thermal neutron detection
Jeffrey S Nico, C. D. Bass, E J Beise, Craig Heimbach, T. Langford
We present the characterization of a liquid scintillator incorporating an aqueous solution of enriched lithium chloride to produce a scintillator with 0.40% 6Li. We report on its performance in terms of optical properties and neutron response. We inc ...
7. Search for a T-odd, P-even Triple Correlation in Neutron Decay
Jeffrey S Nico, T E. Chupp, K P Coulter, R L Cooper, S. J. Freeman, B. K. Fujikawa, A. Garcia, G 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 th ...
8. A New Limit on Time-Reversal Violation in Beta Decay
Hans P Mumm, T E. Chupp, K P Coulter, R L Cooper, S J Freedman, B. K. Fujikawa, A. Garcia, G 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 resu ...
9. A gamma and X-ray dector for cryogenic, high magnetic field applications
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, Brian O'Neill, K. Pulliam, Alan K 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 wa ...
10. Magnetic field effects on large area avalanche photodiodes at cryogenic temperatures
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