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Title: Low-background measurements of neutron emission from Ti metal in pressurized deuterium gas

Abstract

A wide variety of neutron detector systems have been used at various research facilities to search for anomalous neutron emission from deuterated metals. Some of these detector systems are summarized here together with possible sources of spurious signals from electronic noise. During the past two years, we have performed experiments to measure neutron emission from pressurized D{sub 2} gas mixed with various forms of titanium metal chips and sponge. Details concerning the neutron detectors, experimental procedures, and results have been reported previously. Our recent experiments have focused on increasing the low-level neutron emission and finding a way to trigger the emission. To improve our detection sensitivity, we have increased the shielding in our counting laboratory, changed to low-background {sup 3}He tubes, and set up additional detector systems in deep underground counting stations. This report is an update on this experimental work. 7 refs., 5 figs., 4 tabs.

Authors:
; ; ;
Publication Date:
Research Org.:
Los Alamos National Lab., NM (United States)
Sponsoring Org.:
USDOE; USDOE, Washington, DC (United States)
OSTI Identifier:
5039188
Report Number(s):
LA-UR-91-3077; CONF-9106280-1
ON: DE92000184; TRN: 91-032016
DOE Contract Number:
W-7405-ENG-36
Resource Type:
Conference
Resource Relation:
Conference: 2. annual conference on cold fusion, Como (Italy), 29 Jun - 4 Jul 1991
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; DEUTERIUM; NUCLEAR REACTIONS; NEUTRON DETECTORS; EFFICIENCY; TITANIUM; DEUTERATION; NEUTRON EMISSION; BACKGROUND RADIATION; COUNTING TECHNIQUES; NOISE; PERFORMANCE TESTING; PRESSURIZATION; SHIELDING; CHEMICAL REACTIONS; ELEMENTS; EMISSION; HYDROGEN ISOTOPES; ISOTOPES; LIGHT NUCLEI; MEASURING INSTRUMENTS; METALS; NUCLEI; ODD-ODD NUCLEI; RADIATION DETECTORS; RADIATIONS; STABLE ISOTOPES; TESTING; TRANSITION ELEMENTS; 440102* - Radiation Instrumentation- Radiation Dosemeters

Citation Formats

Menlove, H.O., Paciotti, M.A., Claytor, T.N., and Tuggle, D.G.. Low-background measurements of neutron emission from Ti metal in pressurized deuterium gas. United States: N. p., 1991. Web.
Menlove, H.O., Paciotti, M.A., Claytor, T.N., & Tuggle, D.G.. Low-background measurements of neutron emission from Ti metal in pressurized deuterium gas. United States.
Menlove, H.O., Paciotti, M.A., Claytor, T.N., and Tuggle, D.G.. Tue . "Low-background measurements of neutron emission from Ti metal in pressurized deuterium gas". United States. doi:. https://www.osti.gov/servlets/purl/5039188.
@article{osti_5039188,
title = {Low-background measurements of neutron emission from Ti metal in pressurized deuterium gas},
author = {Menlove, H.O. and Paciotti, M.A. and Claytor, T.N. and Tuggle, D.G.},
abstractNote = {A wide variety of neutron detector systems have been used at various research facilities to search for anomalous neutron emission from deuterated metals. Some of these detector systems are summarized here together with possible sources of spurious signals from electronic noise. During the past two years, we have performed experiments to measure neutron emission from pressurized D{sub 2} gas mixed with various forms of titanium metal chips and sponge. Details concerning the neutron detectors, experimental procedures, and results have been reported previously. Our recent experiments have focused on increasing the low-level neutron emission and finding a way to trigger the emission. To improve our detection sensitivity, we have increased the shielding in our counting laboratory, changed to low-background {sup 3}He tubes, and set up additional detector systems in deep underground counting stations. This report is an update on this experimental work. 7 refs., 5 figs., 4 tabs.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jan 01 00:00:00 EST 1991},
month = {Tue Jan 01 00:00:00 EST 1991}
}

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  • During the past year, we have measured neutron emission from samples of titanium (Ti) metal and sponge in pressurized D{sub 2} gas. In January 1990, we improved our sample preparation procedure and our detector sensitivity level so that the neutron-emission measurements are now reproducible, but not yet predictable. We have measured excess neutron emission from the majority of our most recent samples using our high-sensitivity neutron detectors. The improved sensitivity in our new detector system was obtained by using low-radioactive-background stainless steel tubes, a small detector volume with high efficiency, and additional cosmic-ray shielding. Our most sensitive detector consists ofmore » two independent segments making up inner and outer rings of {sup 3}He tubes. The combined total efficiency is 44%. In addition to inner and outer ring segments, we have three separate detector systems operating in parallel control experiments to monitor environmental change. We have measured neutron bursts from a variety of samples containing Ti metal and D{sub 2} gas. The low-multiplicity bursts, emitting from 2 to 10 n, occur much more frequently than the higher multiplicity bursts. By measuring high-mass samples (300 g Ti) over several weeks, with many liquid nitrogen temperature cycles, we have detected neutron emission above the background from most of the samples with a significance level of 3 to 9 {sigma}.« less
  • During the past year, we have measured neutron emission from samples of titanium (Ti) metal and sponge in pressurized D{sub 2} gas. In January 1990, we improved our sample preparation procedure and our detector sensitivity level so that the neutron-emission measurements are now reproducible, but not yet predictable. We have measured excess neutron emission from the majority of our most recent samples using our high-sensitivity neutron detectors. The improved sensitivity in our new detector system was obtained by using low-radioactive-background stainless steel tubes, a small detector volume with high efficiency, and additional cosmic-ray shielding. Our most sensitive detector consists ofmore » two independent segments making up inner and outer rings of {sup 3}He tubes. The combined total efficiency is 44%. In addition to inner and outer ring segments, we have three separate detector systems operating in parallel control experiments to monitor environmental change. We have measured neutron bursts from a variety of samples containing Ti metal and D{sub 2} gas. The low-multiplicity bursts, emitting from 2 to 10 n, occur much more frequently than the higher multiplicity bursts. By measuring high-mass samples (300 g Ti) over several weeks, with many liquid nitrogen temperature cycles, we have detected neutron emission above the background from most of the samples with a significance level of 3 to 9 {sigma}. 10 refs., 7 figs., 2 tabs.« less
  • Experiments using high-efficiency neutron detectors have detected neutron emission from various forms of Pd and Ti metal in pressurized D[sub 2] gas cells and D[sub 2]O electrolysis cells. Four independent neutron detectors based on [sup 3]He gas tubes were used. Both random neutrons (0.05-0.2 n/s) and time-correlated neutron bursts (10-280 n) of [le] 100-[mu]s duration were measured using time-correlation counting techniques. The majority of the neutron burst events occurred at [approximately][minus]30[degrees]C as the samples were warming up from the liquid nitrogen temperature.
  • Mass steam injection into the combustor of a Cheng Cycle turbine can influence combustion characteristics and pollutant formation. When using a Cheng Cycle system based on a Garrett 831 gas turbine liquid fuel, these influences were studied experimentally. Data obtained to date indicate that significant NO /SUB x/ reduction can be achieved without suffering combustion inefficiency or instability.