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1.
在目前的氘氚中子发生器源中子分析过程中,固体氚靶中氚浓度深度分布信息的缺失是普遍遇到的问题。为解决此问题,本文建立了利用伴随粒子能谱反演氚浓度深度分布的模型,采用来自氚钛靶的α实验能谱作为模型测试对象,通过该模型获得了氚钛靶中氚浓度深度分布的数据。结果表明,氚浓度随氚钛靶深度的增加呈双峰趋势,两峰之间的氚浓度波谷位于靶中0.94 μm处,该深度正是入射氘粒子的射程极限。所得的氚浓度深度分布趋势与其他实验方法测量结果相符,表明该模型能为氘氚中子发生器的源中子分析提供即时的氚浓度深度分布信息。 相似文献
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S. Gottesfeld R. E. Anderson D. A. Baker R. D. Bolton K. B. Butterfield F. H. Garzon C. A. Goulding M. W. Johnson E. M. Leonard T. E. Springer T. Zawodzinski 《Journal of Fusion Energy》1990,9(3):287-297
This paper reports a collaborative effort of a team which formed at Los Alamos to investigate the announcement that cold fusion may be occurring in electrochemical cells using palladium cathodes and platinum anodes in a LiOD electrolyte. Four electrochemical cells were construced and operated for 3–5 weeks under various geometrical and electrical conditions. Nuclear diagnostic measurements included high and low resolution gamma-ray spectroscopy, integral neutron counting with well detectors and banks of3He tubes, and neutron spectroscopy withNE-213 scintillators. For one of the cells, the deuterium loading of the cathode was determined from resistance measurements to beD/Pd 0.8. No conclusive evidence was found for the production of neutrons or 2.223-MeV gammas above levels consistent with background. The results of the measurements of tritium levels in the cell electrolytes are also reported. Experiments to reproduce the observation of neutrons from high pressureTi-D
2 gas experiments were also performed with negative results.Work supported by the U.S. Department of Energy under contract with the University of California. 相似文献
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David Albagli Ron Ballinger Vince Cammarata X. Chen Richard M. Crooks Catherine Fiore Marcel P. J. Gaudreau I. Hwang C. K. Li Paul Linsay Stanley C. Luckhardt Ronald R. Parker Richard D. Petrasso Martin O. Schloh Kevin W. Wenzel Mark S. Wrighton 《Journal of Fusion Energy》1990,9(2):133-148
Results of experiments intended to reproduce cold fusion phenomena originally reported by Fleischmann, Pons, and Hawkins are
presented. These experiments were performed on a pair of matched electrochemical cells containing 0.1×9 cm Pd rods that were
operated for 10 days. The cells were analyzed by the following means: (1) constant temperature calorimetry, (2) neutron counting
and γ-ray spectroscopy, (3) mass spectral analysis of4He in effluent gases, and4He and3He within the Pd metal, (4) tritium analysis of the electrolyte solution, and (5) x-ray photoelectron spectroscopy of the
Pd cathode surface. Within estimated levels of accuracy, no excess power output or any other evidence of fusion products was
detected. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(8):667-672
In-situ measurements of the depth profiles of tritium in a titanium tritide target for generating 14-MeV neutrons have been made with the method of the ion beam analysis using the T(d, α)n nuclear reaction. The initial distribution of tritium in the unirradiated target has been observed to be nearly uniform over the depths. After the irradiation of 390-keV D3 + ions at a temperature of about 10°C a dip has been found in the depth profile around the depth of the projected range of the ions. By the successive isochronal anneal-ings at temperatures below 130°C the tritium has been uniformly redistributed. The behavior of tritium in the target and the effectiveness of the depth profiling for evaluating the energy spectrum and the yield of source neutrons are discussed. 相似文献
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H. S. Bosch G. A. Wurden J. Gernhardt F. Karger J. Perchermeier 《Journal of Fusion Energy》1990,9(2):165-186
Following the report of Fleischmann and Pons,(1) we (The Bavarian Bubble Bottle Team) have attempted to reproduce their claims of cold nuclear fusion, and failed. We note
that our measurements would not be able to detect neutrons at the level of Joneset al.(2) Three electrolytic cell experiments were conducted using palladium cathodes and Platinum anodes, in a 0.1-Molar solution
of LiD in heavy water, without any signs of neutrons, tritium, or gammas above backgrounds, and within ±0.3 watt accuracy
calorimetry, no excess heating. Excess heating at the levels of F&P would have been easily detected, if present. Intrinsic
tritium, differing from each D2O bottle tested, was however observed. The longest duration experiment ran for 21 days, and was an attempt to duplicate the
large “melting incident” of F&P. This was terminated on April 28, 1989, by throwing the vacuum-cast 22 gram, deuterium-loaded
palladium cathode directly into liquid nitrogen, immediately next to a bare BF3 counter (backed by 25 cm of moderator), in order to attempt one of the Italian ENEA neutron production variants. No neutrons
above backgrounds were seen, while counting for 1 hour, and also none while the piece warmed to room temperature over the
next hour. Post-mortem analysis of the darkened, hardened Pd piece showed large crystal grains (up to 2 mm × 2 mm), and continuing
evolution of gas bubbles at the grain boundaries even days after the experiment was ended. eight weeks after loading, the
catalytically-active palladium piece continued to create heavy water (with exposure to oxygen in the air). 相似文献
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M. Chen S. G. Steadman M. P. J. Gaudreau S. C. Luckhardt R. R. Parker D. Albagli V. Cammarata M. Schloh M. S. Wrighton K. Kwok C. Thieme D. I. Lowenstein R. Debbe J. J. Reilly 《Journal of Fusion Energy》1990,9(2):155-159
An 80-MeV/c negative muon beam from the Alternating Gradient Synchrotron at Brookhaven National Laboratory was used to investigate
the stopping of muons inside Pd, Ti, and Y targets saturated with deuterium. Neutron emission from the targets was measured
with an array of3He detectors, and in some runs, the temperature of the target was monitored as a function of time, with and without a flux
of muons on the target. The neutron rates were also measured for Pd cathodes in an active electrochemical cell similar in
design to those used in so-called “cold fusion” experiments, and the electrolyte solution was analyzed for excess tritium.
No evidence was found for muon-catalyzed fusion at rates consistent with those claimed in “cold fusion” experiments. Neutron
production from catalyzed fusion due to the presence of deuterium in palladium deuteride, PdD0.7, exposed to muons was determined to be 0.0±0.03 (stat.) ±0.25 (syst.) neutrons per stopped muon. 相似文献
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By means of a fast neutron scintillation spectrometer with one hydrogen-containing detector, the spectra of fast reactor neutrons after passing through various thicknesses of lead, graphite, and iron were measured in the range 0.7–11 MeV. The measurements were carried out in a water-moderated water-cooled experimental reactor in barrier geometry. The results of the experiments enabled us to determine the deformation of the neutron spectrum in relation to the penetration through the layers of material, and to calculate the relaxation lengths and the removal Cross sections. These quantities were punished earlier for fission spectrum neutrons in the energy range 0.7–3 MeV.Translated from Atomnaya Énergiya, Vol. 16, No. 1, pp. 32–40, January, 1964 相似文献
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采用氚化钛源原位辐照和加速器低能电子束加速辐照实验,研究基于氚化钛/单晶硅PN结器件的氚辐伏电池模型和实验室组阵型电池原型样机的长期稳定性。测试电池模型和电池样机的氚辐伏输出随辐照时间的变化,分析辐照对单晶硅PN结型器件的本征暗特性和器件表面层材料缺陷的影响。结果表明,氚化钛源原位辐照电池模型在115 d的辐照中辐伏输出没有明显的衰减,辐照后单晶硅器件的本征暗特性曲线变化微小。电池模型的加速器低能电子束加速辐照实验表明,加速辐照在相同电子注量下对电池造成远大于氚源原位辐照的性能损伤,但损伤仅在辐照最初期快速产生,随后基本保持稳定,电子顺磁能谱(ESR)测试加速辐照60 min单晶硅器件材料的缺陷没有明显增加。组阵型实验室电池原型样机在64个月的室温储存中,基本单元的辐伏输出性能衰减比氚的自发衰变衰减有小幅增大,增大幅度小于11.4%;另外,组阵中单元之间串并联电连接有部分失效,这是后续应重点关注的问题。 相似文献
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《Fusion Engineering and Design》2014,89(9-10):2164-2168
Titanium is contained in lithium titanate which is a tritium breeding material candidate. In the nuclear design, accurate nuclear data are needed. However, few benchmark experiments had been performed for titanium. We performed a benchmark experiment with a titanium assembly and a DT neutron source at JAEA/FNS. The titanium assembly was covered with Li2O blocks in order to reduce background neutrons. Dosimetry reaction rates were measured with niobium, indium and gold foils inside the assembly. And fission rates of 235U were measured by using micro fission chambers. This experiment was analyzed by using the Monte Carlo neutron transport code MCNP5-1.40 with recent nuclear data libraries of ENDF/B-VII.0, ENDF/B-VII.1, JEFF-3.1.2, JENDL-4.0 and JENDL-4.0u1. The calculation results were compared with the measured one in order to validate the nuclear data libraries of titanium. The calculated results with ENDF/B-VII.1 agreed with the measured one the best because the (n,2n) and (n,n′cont) reaction cross section data and resonance parameters were improved. 相似文献
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The intensity of a Ra-Be neutron source is measured by means of the activity induced by the neutrons in an aqueous solution of potassium permanganate. The major part of the activity Mn56 produced by the capture of neutrons slowed down in the water was separated in the form of manganese dioxide fay ordinary filtering. To take account of the neutrons captured by the hydrogen, the ratio of the effective cross sections for capture of thermal neutrons by manganese and by hydrogen was measured and found to be
. It was found that the intensity of the two sources studied amounts to 10,600 ± 500 neutrons/sec per milligram of radium.Work carried out in 1051. Printed in reports of the Academy of Sciences of the USSR in 1951 and 1952. 相似文献
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钯银合金膜可用于熔盐堆尾气中气态氚(HT和T2)的分离与纯化。本文研究了厚度为80 μm的钯银合金膜在纯H2气氛中及Ar气存在下对H2的分离效果。结果表明,渗氢过程中氢原子在膜内部的体相扩散是控制速率的关键。Ar气存在时,在钯银合金膜工作温度为480 ℃、混合气体进气流速为100 mL/min、氢分压差为20~100 kPa的条件下,钯银合金膜对H2气的渗透通量随氢分压差的增大而增加,随Ar气浓度的升高而减小。在氢分压差相同的条件下,纯氢的渗透通量明显高于Ar-H2混合气的渗透通量,说明钯银合金膜受Ar气的影响分离效果变差。渗氢后的钯银合金膜表面变得光滑,有晶界形成。 相似文献
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The natural tendency of identical bosons to clump in ordinary space is ascribed to a symmetry force, whose action is equivalent to the effects of the wavefunction for a collection of degenerate bosons. The symmetry force is hypothesized to produce clusters of deuterons in the lattice for a high enough stoichiometric ratio of deuterons to Pd atoms and to catalyze tunneling to achieve cold fusion. A semiempirical power law is derived as a function of the number of deuterons,N, in a representative cluster: for large enoughN the fusion products are He4 plus heat, while for small clusters the fusion rate is much lower and the Oppenheimer-Phillips process favors the production of tritium over neutrons. Pulsed production of heat and neutrons is suggested. Finally, three additional roles in physics for the symmetry force are hypothesized. 相似文献
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Confirmatory experiments were conducted to assess the potential for nuclear fusion related emissions of neutrons and tritium during neutron-seeded acoustic cavitation of deuterated acetone. Corresponding control experiments were conducted with normal acetone. Statistically significant (5–11S.D. increased) emissions of 2.45 MeV neutrons and tritium were measured during cavitation experiments with chilled deuterated acetone. Control experiments with normal acetone and irradiation alone did not result in tritium activity or neutron emissions. Insights from imaging studies of bubble clusters and shock trace signals relating to bubble nuclear fusion are discussed. 相似文献
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用厚靶氘氚(D-T)反应中子产额的计算方法模拟计算了入射氘离子能量为120 keV时D-T中子源的中子产额。研究了氘离子源产生的束流中单原子氘离子(D+)及双原子氘离子(D2+)比例对中子产额的影响。结果表明,提高D+比例,同时降低D2+比例将有效提高中子产额。另外还研究了不同靶膜材料及组分引起的中子产额变化。表明中子产额与靶膜中氚的含量成正比,与靶膜元素的原子质量成反比。同时分析讨论了离子源品质及靶参数对中子源整体性能的影响,得出离子源束流品质的提高对中子源整体的设计至关重要。最后,模拟计算了靶膜表面有氧化层情况下中子产额的变化,并与实验结果作了对比。在此基础上提出了一种新的靶设计方案,并对其物理可行性进行了研究。 相似文献
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H. O. Menlove M. M. Fowler E. Garcia M. C. Miller M. A. Paciotti R. R. Ryan S. E. Jones 《Journal of Fusion Energy》1990,9(4):495-506
Experiments using high-efficiency neutron detectors have detected neutron emission from various forms of Pd and Ti metal in pressurized D2 gas cells and D2O electrolysis cells. Four independent neutron detectors based on3He gas tubes were used. Both random neutrons (0.05–0.2 n/s) and time-correlated neutron bursts (10–280 n) of 100-s duration were measured using time-correlation counting techniques. The majority of the neutron burst events occurred at –30°C as the samples were warming up from the liquid nitrogen temperature. 相似文献
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R. T. Santoro R. G. Alsmiller Jr. J. M. Barnes G. T. Chapman J. S. Tang 《Journal of Fusion Energy》1982,2(6):403-412
Integral experiments that measure the transport of 14 MeV neutrons through a 0.30-m-diameter duct having a length-to-diameter ratio of 2.83 that is partially plugged with a 0.15 m diameter, 0.51 m long shield comprised of alternating layers of stainless steel type 304 and borated polyethylene have been carried out at the Oak Ridge National Laboratory. Measured and calculated neutron and gamma ray energy spectra are compared at several locations relative to the mouth of the duct. The measured spectra were obtained using an NE-213 liquid scintillator detector with pulse shape discrimination methods used to simultaneously resolve neutron and gamma ray events. The calculated spectra were obtained using a computer code network that incorporates two radiation transport methods: discrete ordinates (with P3 multigroup cross sections) and Monte Carlo (with continuous point cross sections). The two radiation transport methods are required to account for neutrons that singly scatter from the duct to the detectors. The calculated and measured neutron energy spectra above 850 keV agree within 5–50% depending on detector location and neutron energy. The calculated and measured gamma ray energy spectra above 750 keV are also in favorable agreement, 5–50%, depending on detector location and gamma ray energy. 相似文献