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1

Intense fusion neutron sources  

NASA Astrophysics Data System (ADS)

The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 1015-1021 neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 1020 neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

Kuteev, B. V.; Goncharov, P. R.; Sergeev, V. Yu.; Khripunov, V. I.

2010-04-01

2

Intense fusion neutron sources  

SciTech Connect

The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 10{sup 15}-10{sup 21} neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 10{sup 20} neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

Kuteev, B. V. [Russian Research Centre Kurchatov Institute (Russian Federation); Goncharov, P. R.; Sergeev, V. Yu. [St. Petersburg State Polytechnic University (Russian Federation); Khripunov, V. I. [Russian Research Centre Kurchatov Institute (Russian Federation)

2010-04-15

3

Neutron sources and applications  

SciTech Connect

Review of Neutron Sources and Applications was held at Oak Brook, Illinois, during September 8--10, 1992. This review involved some 70 national and international experts in different areas of neutron research, sources, and applications. Separate working groups were asked to (1) review the current status of advanced research reactors and spallation sources; and (2) provide an update on scientific, technological, and medical applications, including neutron scattering research in a number of disciplines, isotope production, materials irradiation, and other important uses of neutron sources such as materials analysis and fundamental neutron physics. This report summarizes the findings and conclusions of the different working groups involved in the review, and contains some of the best current expertise on neutron sources and applications.

Price, D.L. [ed.] [Argonne National Lab., IL (United States); Rush, J.J. [ed.] [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

1994-01-01

4

Intense fusion neutron sources  

Microsoft Academic Search

The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 1015-1021 neutrons\\/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion

B. V. Kuteev; P. R. Goncharov; V. Yu. Sergeev; V. I. Khripunov

2010-01-01

5

Intense fusion neutron sources  

Microsoft Academic Search

The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects\\u000a of creating fission and fusion neutron sources with intensities of 10151021 neutrons\\/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes\\u000a and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of\\u000a fusion

B. V. Kuteev; P. R. Goncharov; V. Yu. Sergeev; V. I. Khripunov

2010-01-01

6

Italian neutron sources  

NASA Astrophysics Data System (ADS)

Many research activities, instrumental analysis, studies of radiation damage, etc., require neutron sources. The main neutron sources present in Italy are described in three different sections: nuclear research reactors, accelerator driven, and metrology stations. The nuclear research reactors of LENA (University of Pavia) and ENEA Casaccia are described in terms of irradiation facilities available, neutron flux for each of them and the main activities carried out by each research centre. In the second section, the Frascati Neutron Generator (FNG), the Frascati Beam-Test Facility (BTF) and their main features are reported. In the last section there is a detailed description of the institutional role and the main activities carried out in the field of neutron metrology by the National Institute for Metrology of Ionizing Radiation (INMRI) with a brief description of neutron sources of which the institute is endowed.

Prata, M.; Alloni, D.; De Felice, P.; Palomba, M.; Pietropaolo, A.; Pillon, M.; Quintieri, L.; Santagata, A.; Valente, P.

2014-11-01

7

Pulsed spallation neutron sources  

SciTech Connect

This paper reviews the early history of pulsed spallation neutron source development ar Argonne and provides an overview of existing sources world wide. A number of proposals for machines more powerful than currently exist are under development, which are briefly described. The author reviews the status of the Intense Pulsed Neutron Source, its instrumentation, and its user program, and provide a few examples of applications in fundamental condensed matter physics, materials science and technology.

Carpenter, J.M. [Argonne National Lab., IL (United States). Intense Pulsed Neutron Source Div.

1996-05-01

8

The Advanced Neutron Source  

SciTech Connect

The Advanced Neutron Source (ANS) is a new user experimental facility planned to be operational at Oak Ridge in the late 1990's. The centerpiece of the ANS will be a steady-state research reactor of unprecedented thermal neutron flux ({phi}{sub th} {approx} 9{center dot}10{sup 19} m{sup -2}{center dot}s{sup -1}) accompanied by extensive and comprehensive equipment and facilities for neutron-based research. 5 refs., 5 figs.

Hayter, J.B.

1989-01-01

9

Therapeutic aspects of radio-isotopes in hepatobiliary malignancy.  

PubMed

Liver tumours frequently present at a late stage and only a minority of patients are likely to benefit from resection or transplantation. Inoperable tumours carry a grave prognosis. External beam irradiation of the liver is dose-limited by the radiosensitivity of hepatocytes, particularly in the presence of cirrhosis, but internal radiation using radio-isotope sources can achieve more selective irradiation of the chosen field. Sealed sources are dose-limited by their effects on surrounding tissues, whereas with unsealed sources the dose of radio-isotope administered is limited by bone marrow suppression. Iridium-192 wires are most frequently employed as a sealed intracavitary source. They may be inserted surgically, transhepatically or endoscopically. Doses of up to 60 Gy can be delivered to a malignant biliary stricture without damage to the surrounding parenchyma. The incidence of cholangitis is low if treatment is administered after insertion of an endoprosthesis. Unsealed radio-isotope sources may be injected directly into the tumour, administered embolically via the hepatic artery in the form of microspheres or lipid droplets, or given via parenteral infusion attached to tumour-specific antibodies. Of these vehicles, the lipid agent Lipiodol appears to be the most effective and can deliver a potentially lethal dose of radiation to small tumours. Host reaction to the injected antibody remains a major drawback to the use of monoclonal antibodies as targeting agents. Iodine-131 is a beta- and gamma-emitter, producing a local tumoricidal effect and allowing accurate dosimetry by means of external scintigraphy. Yttrium-90 is a pure beta-emitter with a greater maximum beta energy and cytotoxic range; however, it is retained in bony tissues, resulting in a dose-related risk of marrow suppression. Bone absorption cannot be measured by external imaging owing to the absence of gamma emission. This lack of accurate dosimetry, coupled with the toxic side-effects of yttrium treatment, make iodine-131 the current isotope of choice. PMID:1655152

Novell, J R; Hilson, A; Hobbs, K E

1991-08-01

10

Intense pulsed neutron sources  

SciTech Connect

Accelerator requirements for pulsed spallation neutron sources are stated. Brief descriptions of the Argonne IPNS-I, the Japanese KENS, Los Alamos Scientific Laboratory WNR/PSR, the Rutherford Laboratory SNS, and the West German SNQ facilities are presented.

Kustom, R.L.

1981-01-01

11

Neutron source progress report  

Microsoft Academic Search

This document is a de-classified June 1948 progress report on neutron source development at Monsanto Chemical`s Mound facility. Specific sources reviewed are: (1) Postum-beryllium, (2) Postum-Boron and Postum-Fluoborate, and (3) Postum-Lithium and Postum-Sodium. Preparation of each source is discussed, and some of their physical properties are given.

L. Bentz; J. Birden; R. Hertz

1948-01-01

12

Ultrashort pulsed neutron source.  

PubMed

We report on a novel compact laser-driven neutron source with an unprecedented short pulse duration (<50??ps) and high peak flux (>10(18)??n/cm(2)/s), an order of magnitude higher than any existing source. In our experiments, high-energy electron jets are generated from thin (<3???m) plastic targets irradiated by a petawatt laser. These intense electron beams are employed to generate neutrons from a metal converter. Our method opens venues for enhancing neutron radiography contrast and for creating astrophysical conditions of heavy element synthesis in the laboratory. PMID:25396373

Pomerantz, I; McCary, E; Meadows, A R; Arefiev, A; Bernstein, A C; Chester, C; Cortez, J; Donovan, M E; Dyer, G; Gaul, E W; Hamilton, D; Kuk, D; Lestrade, A C; Wang, C; Ditmire, T; Hegelich, B M

2014-10-31

13

Fundamental Neutron Physics Beamline Spallation Neutron Source  

E-print Network

Fundamental Neutron Physics Beamline at the Spallation Neutron Source Overview and Status 21 that can utilize the full cold neutron energy spectrum. ­ The external facility will be appropriate for experiments that need ultra cold neutrons generated in superfluid Helium. · The beamlines consist of

14

SNS: Spallation Neutron Source  

NSDL National Science Digital Library

The Spallation Neutron Source (SNS) is an accelerator-based neutron source currently being built by the United States Department of Energy. Users can find out about upcoming workshops, conferences, and other events dealing with the accelerator, which is scheduled to be completed in 2006. By downloading a series of materials, users can learn about SNS's benefits and mechanisms. Researchers can discover SNS's mission, instrumentation, moderators, and detectors. The website provides live video of the construction site. Visitors can also learn about employment opportunities.

15

Accelerator-based Neutron Sources  

Microsoft Academic Search

Since the earliest experiments defining the properties of the neutron, accelerators have played an important role in providing neutrons for research and applications. For many years, neutrons produced at accelerator facilities have complemented capabilities available from reactor-based sources. Now, with the declining availability of reactor facilities, upgrades of existing accelerator facilities and proposed new, more powerful accelerator-based sources will be

James B. Ball

1997-01-01

16

RTGs - The powering of Ulysses. [Radio-isotope Thermoelectric Generator  

NASA Technical Reports Server (NTRS)

The radio-isotope thermoelectric generator (RTG) for Ulysses' electronic supply is described noting that lack of sufficient sunlight renders usual solar cell power generation ineffective due to increased distance from sun. The history of the RTG in the U.S.A. is reviewed citing the first RTG launch in 1961 with an electrical output of 2.7 W and the improved Ulysses RTG, which provides 285 W at mission beginning and 250 W at mission end. The RTG concept is discussed including the most recent RTG technology developed by the DOE, the General Purpose Heat Source RTG (GPHS-RTG). The system relies upon heat generated by radioactive decay using radioactive plutonium-238, which is converted directly to energy using the Seebeck method.

Mastal, E. F.; Campbell, R. W.

1990-01-01

17

Spallation Neutron Source Materials Studies  

Microsoft Academic Search

Operation of accelerator facilities such as Los Alamos Neutron Science Center (LANSCE), ISIS at Rutherford Appleton Laboratory, the Swiss Institute Neutron Source (SINQ) at Paul Scherrer Institute, and others has provided valuable information on materials performance in high energy particle beams and high energy neutron environments. The Accelerator Production of Tritium (APT) project is sponsoring an extensive series of tests

W. F. Sommer

1998-01-01

18

Neutron producing target for accelerator based neutron source for  

E-print Network

247 Neutron producing target for accelerator based neutron source for NCT V. Belov1 , S. Fadeev1, Russia Summary Neutron producing targets for novel accelerator based neutron source [1, 2] are presented Neutron producing target is one of the main elements of proposed accelerator based facility for neutron

Taskaev, Sergey Yur'evich

19

Curium-248 standard neutron source  

PubMed

A new standard neutron source based on curium-248 has been developed, prepared, and certified. The curium-248 isotope is more long-lived than californium-252. The active core of this source is a pellet made of an alloy of platinum with curium. The measured full neutron yield for this source is 2.30 x 10(4) s(-1) with 4% error at 0.95 confidence. PMID:11003529

Radchenko; Ryabinin; Andreytchuk; Gavrilov; Karelin

2000-10-01

20

Next Generation Spallation Neutron Sources  

NASA Astrophysics Data System (ADS)

Neutron Scattering Experiments are traditionally done at nuclear reactors where high neutron fluxes are available from fission inside the reactor core. Naturally these are cw sources, which makes a whole class of time resolved experiments difficult to perform. Pulsed neutron sources, based on the spallation of neutrons by impinging an intense proton beam on a high atomic number target material, have therefore generated a large interest ever since they were put into operation. So far the typical integrated neutron flux is one or two orders of magnitude smaller than in a reactor. With the Spallation Neutron Source (SNS*) at Oak Ridge National Lab and the Japanese Hadron Project (J-PARC) at JAERI in Japan two second generation facilities are under construction that will provide average neutron fluxes exceeding those of reactors and peak fluxes that will allow new science to be done. The European Spallation Source, a project that still is in the planning stage, would even go beyond that. The talk will start out with the existing Spallation Sources and give an overview about the two construction projects focusing on the SNS presently foreseen to be finished in 2006. * SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. SNS is a partnership of six national laboratories: Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos and Oak Ridge.

Holtkamp, Norbert

2004-05-01

21

Research on fusion neutron sources  

NASA Astrophysics Data System (ADS)

The use of fusion devices as powerful neutron sources has been discussed for decades. Whereas the successful route to a commercial fusion power reactor demands steady state stable operation combined with the high efficiency required to make electricity production economic, the alternative approach to advancing the use of fusion is free of many of complications connected with the requirements for economic power generation and uses the already achieved knowledge of Fusion physics and developed Fusion technologies. "Fusion for Neutrons" (F4N), has now been re-visited, inspired by recent progress achieved on comparably compact fusion devices, based on the Spherical Tokamak (ST) concept. Freed from the requirement to produce much more electricity than used to drive it, a fusion neutron source could be efficiently used for many commercial applications, and also to support the goal of producing energy by nuclear power. The possibility to use a small or medium size ST as a powerful or intense steady-state fusion neutron source (FNS) is discussed in this paper in comparison with the use of traditional high aspect ratio tokamaks. An overview of various conceptual designs of compact fusion neutron sources based on the ST concept is given and they are compared with a recently proposed Super Compact Fusion Neutron Source (SCFNS), with major radius as low as 0.5 metres but still able to produce several MW of neutrons in a steady-state regime.

Gryaznevich, M. P.

2012-06-01

22

Materials for spallation neutron sources  

SciTech Connect

The Workshop on Materials for Spallation Neutron Sources at the Los Alamos Neutron Science Center, February 6 to 10, 1995, gathered scientists from Department of Energy national laboratories, other federal institutions, universities, and industry to discuss areas in which work is needed, successful designs and use of materials, and opportunities for further studies. During the first day of the workshop, speakers presented overviews of current spallation neutron sources. During the next 3 days, seven panels allowed speakers to present information on a variety of topics ranging from experimental and theoretical considerations on radiation damage to materials safety issues. An attempt was made to identify specific problems that require attention within the context of spallation neutron sources. This proceedings is a collection of summaries from the overview sessions and the panel presentations.

Sommer, W.F.; Daemen, L.L. [comps.

1996-03-01

23

Spallation source neutron target systems  

SciTech Connect

This is the final report for a two-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project sought to design a next-generation spallation source neutron target system for the Manuel Lujan, Jr., Neutron Scattering Center (LANSCE) at Los Alamos. It has been recognized for some time that new advanced neutron sources are needed in the US if the country is to maintain a competitive position in several important scientific and technological areas. A recent DOE panel concluded that the proposed Advanced Neutron Source (a nuclear reactor at Oak Ridge National Laboratory) and a high-power pulsed spallation source are both needed in the near future. One of the most technically challenging designs for a spallation source is the target station itself and, more specifically, the target-moderator-reflector arrangement. Los Alamos has demonstrated capabilities in designing, building, and operating high-power spallation-neutron-source target stations. Most of the new design ideas proposed worldwide for target system design for the next generation pulsed spallation source have either been conceived and implemented at LANSCE or proposed by LANSCE target system designers. These concepts include split targets, flux-trap moderators, back scattering and composite moderators, and composite reflectors.

Russell, G.; Brown, R.; Collier, M.; Donahue, J. [and others

1996-07-01

24

The tokamak as a neutron source  

SciTech Connect

This paper describes the tokamak in its role as a neutron source, with emphasis on experimental results for D-D neutron production. The sections summarize tokamak operation, sources of fusion and non-fusion neutrons, principal neutron detection methods and their calibration, neutron energy spectra and fluxes outside the tokamak plasma chamber, history of neutron production in tokamaks, neutron emission and fusion power gain from JET and TFTR (the largest present-day tokamaks), and D-T neutron production from burnup of D-D tritons. This paper also discusses the prospects for future tokamak neutron production and potential applications of tokamak neutron sources. 100 refs., 16 figs., 4 tabs.

Hendel, H.W.; Jassby, D.L.

1989-11-01

25

Status of the advanced neutron source. [Advanced Neutron Source Reactor  

SciTech Connect

Research reactors in the United States are becoming more and more outdated, at a time when neutron scattering is being recognized as an increasingly important technique in areas vital to the US scientific and technological future. The last US research reactor was constructed over 25 years ago, whereas new facilities have been built or are under construction in Japan, Russia and, especially, Western Europe, which now has a commanding lead in this important field. Concern over this situation in the early 1980's by a number of organizations, including the National Academy of Sciences, led to a recommendation that design work start urgently on an advanced US neutron research facility. This recommendation is realized in the Advanced Neutron Source Project. The centerpiece of the Advanced Neutron Source will be a new research reactor of unprecedented flux (>7.5 {times} 10{sup 19} m{sup {minus}2}{center dot}s{sup {minus}1}), equipped with a wide variety of state-of-the-art spectrometers and diffractometers on hot, thermal, and cold neutron beams. Very cold and ultracold neutron beams will also be provided for specialized experiments. This paper will discuss the current status of the design and the plans for scattering instrumentation. 5 refs.

Hayter, J.B.

1990-01-01

26

FIGARO : measuring neutron emission spectra with a white neutron source /.  

SciTech Connect

Neutron emission spectra from reactions induced by fast neutrons are of importance in basic physics and applications. Very few data are available in the literature over a wide range of incident neutron energies such as produced with a white neutron source. The FIGARO facility at the WNR/LANSCE neutron source has been established to measure such neutron emission over a range of incident neutron energies from 1 to over 100 MeV. Using the time-of-flight technique twice (once to determine the incident neutron energy and again to determine the outgoing neutron energy), we are measuring neutron emission spectra for several reactions such as (n,n') and (n,f). Neutron emission from inelastic scattering gives information on the level density of excited states of the target nucleus. Our first measurements are on structural materials such as iron.

Haight, Robert C.; O'Donnell, J. M.; Zanini, L.; Devlin, M.; Rochman, D. (Dimitri)

2002-01-01

27

Neutron-emission measurements at a white neutron source  

SciTech Connect

Data on the spectrum of neutrons emittcd from neutron-induced reactions are important in basic nuclear physics and in applications. Our program studies neutron emission from inelastic scattering as well as fission neutron spectra. A ''white'' neutron source (continuous in energy) allows measurements over a wide range of neutron energies all in one experiment. We use the tast neutron source at the Los Alamos Neutron Science Center for incident neutron energies from 0.5 MeV to 200 MeV These experiments are based on double time-of-flight techniques to determine the energies of the incident and emitted neutrons. For the fission neutron measurements, parallel-plate ionization or avalanche detectors identify fission in actinide samples and give the required fast timing pulse. For inelastic scattering, gamma-ray detectors provide the timing and energy spectroscopy. A large neutron-detector array detects the emitted neutrons. Time-of-flight techniques are used to measure the energies of both the incident and emitted neutrons. Design considerations for the array include neutron-gamma discrimination, neutron energy resolution, angular coverage, segmentation, detector efficiency calibration and data acquisition. We have made preliminary measurements of the fission neutron spectra from {sup 235}U, {sup 238}U, {sup 237}Np and {sup 239}Pu. Neutron emission spectra from inelastic scattering on iron and nickel have also been investigated. The results obtained will be compared with evaluated data.

Haight, Robert C [Los Alamos National Laboratory

2010-01-01

28

Laser-Driven Neutron Sources  

NASA Astrophysics Data System (ADS)

We are investigating the possibility of applying fast pulse lasers to drive low cost, deuterium-tritium, point neutron source for fusion materials testing at high fluxes. Compared with conventional beam-target neutron sources with steady-state liquid cooling ,the driver energy here is removed by sacrificial vaporization of a target spot of a few-hundred-microns dimensions. The resulting small source volumes offer the potential for a high flux of 14MeV neutrons at close-coupled, miniaturized (*1mm) test specimens of fusion-relevant materials (e.g., vanadium alloys, SiC-SiC and C-C composites, etc). Recent effort has been devoted to a target based on D-T atomic gas clusters and experimental results will be reported elsewhere at this meeting [Ditmire et al]. Previous laser interaction measurements with clusters indicate very high (>80%) conversion efficiency of incident laser energy to fast ions. In our present target concept to exploit this phenomenon, the laser energy interacts with a central DT gas cluster and the escaping fast ions are absorbed in a surrounding DT ``collar" to produce 14MeV, beam-target neutrons. The collar may be solid DT or simply a higher-density, concentric gas cluster. With laser conditions of 100J, 100Hz (i.e., 10kW average power), we estimate steady-state, uncollided 14MeV neutron flux at a close-coupled material specimen of around1015cm-2s-1 at a laser intensity of 1017W/cm2.

Perkins, L. John; Ditmire, Todd; Logan, B. Grant; Powell, Howard

1999-11-01

29

Ion sources for sealed neutron tubes  

SciTech Connect

In this paper, we will compare a number of gas ion sources that can be used in sealed neutron tubes. The characteristics of the most popular ion source, the axial Penning discharge will be discussed as part of the zetatron neutron generator. Other sources to be discussed include the SAMIS source and RF ion source. {copyright} {ital 1997 American Institute of Physics.}

Burns, E.J. [Neutron Tube Department, Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185-0516 (United States); Bischoff, G.C. [Lockheed Martin Specialty Components, P.O. Box 2908, Largo, Florida 34649-2908 (United States)

1997-02-01

30

Californium-252 Neutron Sources for Medical Applications  

SciTech Connect

Californium-252 neutron sources are being prepared to investigate the value of this radionuclide in diagnosing and treating diseases. A source resembling a cell-loaded radium needle was developed for neutron therapy. Since therapy needles are normally implanted in the body, very conservative design criteria were established to prevent leakage of radioactive. Methods are being developed to prepare very intense californium sources that could be used eventually for neutron radiography and for diagnosis by neutron activation analysis. This paper discusses these methods.

Boulogne, A.R.

2001-08-29

31

Neutron calibration facility with radioactive neutron sources at KRISS.  

PubMed

For the purpose of radiation protection, the reference neutron field for calibration of neutron monitors was constructed using radioactive neutron sources-bare-(252)Cf, D(2)O-moderated (252)Cf and (241)Am-Be(alpha,n)-at Korea Research Institute of Standards and Science (KRISS). The well-specified neutron source with its emission rate and the anisotropy was installed at the centre of the neutron irradiation room, which is 6.6 x 7.6 x 6.3 m(3) in size. The neutron spectra of each source was measured using the Bonner sphere spectrometer (KRISS-BSS). Calculations using MCNP5 with realistic geometry and materials in the neutron irradiation room were performed. The calculations and measurements were found to be in good agreement, showing that the neutron calibration facility at KRISS is well established. PMID:17575300

Park, H; Kim, J; Choi, K-O

2007-01-01

32

Fission neutron source in Rome  

NASA Astrophysics Data System (ADS)

A fission neutron source is operating in Rome at the ENEA Casaccia Research Center since 1971, consisting of a low power fast reactor named RSV-Tapiro. it is employed for a variety of experiments, including dosimetry, material testing, radiation protection and biology. In particular, application to experimental radiobiology includes studies of the biological action of neutrons in the whole-body irradiated animal, or in specialized systems in vivo or in vitro. For his purpose a vertical irradiation facility was originally constructed. Recently, a new horizontal irradiation facility has been designed to allow the exposure of larger samples or larger sample batches at one time. Dosimetry at the sample irradiation positions is routinely carried out by the conventional method of using two ion chambers. This physical dosimetry has recently been compared with the results of biological dosimetry based on the detection of chromosomal aberrations in peripheral blood human lymphocytes irradiated in vitro. A characterization of the radiation quality in the two configurations has been carried out by tissue equivalent proportional counter microdosimetry measurements. Information about the main characteristics of the reactor and the two irradiation facilities is provided and relevant results of the various measurements are summarized. Radiobiological results obtained using this neutron source are also briefly outlined.

Coppola, Mario; Di Majo, V.; Ingrao, G.; Rebessi, S.; Testa, A.

1997-02-01

33

International workshop on cold neutron sources  

Microsoft Academic Search

The first meeting devoted to cold neutron sources was held at the Los Alamos National Laboratory on March 5 to 8, 1990. Cosponsored by Los Alamos and Oak Ridge National Laboratories, the meeting was organized as an International Workshop on Cold Neutron Sources and brought together experts in the field of cold-neutron-source design for reactors and spallation sources. Eighty-four people

G. J. Russell; C. D. West

1991-01-01

34

THE SPALLATION NEUTRON SOURCE PROJECT - PHYSICAL CHALLENGES.  

SciTech Connect

The Spallation Neutron Source (SNS) is designed to reach an average proton beam power of 1.4 MW for pulsed neutron production. This paper summarizes design aspects and physical challenges to the project.

WEI,J.

2002-06-03

35

14-MeV neutron pulse source  

NASA Astrophysics Data System (ADS)

In order to study the neutron measurement techniques set up in laser interaction experiments with D-T filled targets, we have designed and operated a 14-MeV neutron short pulse source. The device is a sealed neutron gas tube with a hot cathode supplied by an adjustable high-voltage pulse generator. Its principle consists in discharging a coaxial cable, held at the generator voltage, into the high-impedance neutron head. We then obtain a neutron pulse train with each pulse duration determined by the length of the cable. This source generates a total routine yield of 107 neutrons. A small sized head will be inserted into interaction chambers.

Garconnet, J. P.; de Mascureau, J.; Boutry, B.; Pauwels, J. C.; Bernardet, H.

1985-05-01

36

Ion sources for sealed neutron tubes  

SciTech Connect

Fast and thermal neutron activation analysis with sealed neutron generators has been used to detect oil (oil logging), hazardous waste, fissile material, explosives, and contraband (drugs). Sealed neutron generators, used in the above applications, must be small and portable, have good electrical efficiency and long life. The ion sources used in the sealed neutron tubes require high gas utilization efficiencies or low pressure operation with high ionization efficiencies. In this paper, the authors compare a number of gas ion sources that can be used in sealed neutron tubes. The characteristics of the most popular ion source, the axial Penning discharge will be discussed as part of the zetatron neutron generator. Other sources to be discussed include the SAMIS source and RF ion source.

Burns, E.J.T. [Sandia National Labs., Albuquerque, NM (United States). Neutron Tube Dept.; Bischoff, G.C. [Lockheed Martin Specialty Components, Largo, FL (United States)

1996-11-01

37

The continuous spallation neutron source SINQ  

Microsoft Academic Search

SINQ, at the Paul Scherrer Institut (PSI) in Villigen, Switzerland, is the first continuous spallation neutron source worldwide. The continuous flow of neutrons and the vertical target arrangement is responsible for an instrument suite characteristic of that installed at reactors. The neutrons are extracted by six double beam tubes which are all tangential with respect to the target: two of

Peter Allenspach

2000-01-01

38

New sources and instrumentation for neutron science  

NASA Astrophysics Data System (ADS)

Neutron-scattering research has a lot to do with our everyday lives. Things like medicine, food, electronics, cars and airplanes have all been improved by neutron-scattering research. Neutron research also helps scientists improve materials used in a multitude of different products, such as high-temperature superconductors, powerful lightweight magnets, stronger, lighter plastic products etc. Neutron scattering is one of the most effective ways to obtain information on both, the structure and the dynamics of condensed matter. Most of the world's neutron sources were built decades ago, and although the uses and demand for neutrons have increased throughout the years, few new sources have been built. The new construction, accelerator-based neutron source, the spallation source will provide the most intense pulsed neutron beams in the world for scientific research and industrial development. In this paper it will be described what neutrons are and what unique properties make them useful for science, how spallation source is designed to produce neutron beams and the experimental instruments that will use those beams. Finally, it will be described how past neutron research has affected our everyday lives and what we might expect from the most exciting future applications.

Gil, Alina

2011-04-01

39

Switchable radioactive neutron source device  

DOEpatents

This invention is a switchable neutron generating apparatus comprised of a pair of plates, the first plate having an alpha emitter section on it and the second plate having a target material portion on it which generates neutrons when its nuclei absorb an alpha particle. In operation, the alpha portion of the first plate is aligned with the neutron portion of the second plate to produce neutrons and brought out of alignment to cease production of neutrons. 3 figs.

Stanford, G.S.; Rhodes, E.A.; Devolpi, A.; Boyar, R.E.

1987-11-06

40

Neutron sources: present practice and future potential  

SciTech Connect

The present capability and future potential of accelerator-based monoenergetic and white neutron sources are outlined in the context of fundamental and applied neutron-nuclear research. The neutron energy range extends from thermal to 500+ MeV, and the time domain from steady-state to pico-second pulsed sources. Accelerator technology is summarized, including the production of intense light-ion, heavy-ion and electron beams. Target capabilities are discussed with attention to neutron-production efficiency and power-handling capabilities. The status of underlying neutron-producing reactions is summarized. The present and future use of neutron sources in: (i) fundamental neutron-nuclear research, (ii) nuclear-data acquisition, (iii) materials-damage studies, (iv) engineering test, and (v) biomedical applications are discussed. Emphasis is given to current status, near-term advances well within current technology, and to long-range projections.

Cierjacks, S.; Smith, A.B.

1988-01-01

41

Spallation Neutron Source reaches megawatt power  

ScienceCinema

The Department of Energy's Spallation Neutron Source (SNS), already the world's most powerful facility for pulsed neutron scattering science, is now the first pulsed spallation neutron source to break the one-megawatt barrier. "Advances in the materials sciences are fundamental to the development of clean and sustainable energy technologies. In reaching this milestone of operating power, the Spallation Neutron Source is providing scientists with an unmatched resource for unlocking the secrets of materials at the molecular level," said Dr. William F. Brinkman, Director of DOE's Office of Science.

Dr. William F. Brinkman

2010-01-08

42

Dose measurements around spallation neutron sources.  

PubMed

Neutron dose measurements and calculations around spallation sources appear to be of great importance in shielding research. Two spallation sources were irradiated by high-energy proton beams delivered by the Nuclotron accelerator (JINR), Dubna. Neutrons produced by the spallation sources were measured by using solid-state nuclear track detectors. In addition, neutron dose was calculated after polyethylene and concrete, using a phenomenological model based on empirical relations applied in high-energy physics. The study provides an analytical and experimental neutron benchmark analysis using the transmission factor and a comparison between the experimental results and calculations. PMID:18957519

Fragopoulou, M; Stoulos, S; Manolopoulou, M; Krivopustov, M; Zamani, M

2008-01-01

43

A Neutron Diffractometer for a Long Pulsed Neutron Source  

NASA Astrophysics Data System (ADS)

Long pulsed neutron sources are being actively developed as small university based sources and are being considered for the next generation of high powered sources, such as the European Neutron Source (ESS) and the Spallation Neutron Source (SNS) second target station. New instrumentation concepts will be required to effectively utilize the full spectrum of neutrons generated by these sources. Neutron diffractometers, which utilize time-of-flight (TOF) techniques for wavelength resolution, are particularly problematic. We describe an instrument for a long pulsed source that provides resolution comparable to that obtained on short pulsed sources without the need of long incident flight paths. We accomplish this by utilizing high speed choppers to impose a time structure on the spectrum of incident neutrons. By strategically positioning these choppers the response matrix assumes a convenient form that can be deconvoluted from the measured TOF spectrum to produce the diffraction pattern of the sample. We compare the performance of this instrument to other possible diffraction instruments that could be utilized on a long pulsed source.

Sokol, Paul; Wang, Cailin

44

Pulsed thermal neutron source at the fast neutron generator  

Microsoft Academic Search

A small pulsed thermal neutron source has been designed based on results of the MCNP simulations of the thermalization of 14MeV neutrons in a cluster-moderator which consists of small moderating cells decoupled by an absorber. Optimum dimensions of the single cell and of the whole cluster have been selected, considering the thermal neutron intensity and the short decay time of

Grzegorz Tracz; Krzysztof Drozdowicz; Barbara Gaba?ska; Ewa Krynicka

2009-01-01

45

Nested Focusing Optics for Compact Neutron Sources  

NASA Technical Reports Server (NTRS)

NASA's Marshall Space Flight Center, the Massachusetts Institute of Technology (MIT), and the University of Alabama Huntsville (UAH) have developed novel neutron grazing incidence optics for use with small-scale portable neutron generators. The technology was developed to enable the use of commercially available neutron generators for applications requiring high flux densities, including high performance imaging and analysis. Nested grazing incidence mirror optics, with high collection efficiency, are used to produce divergent, parallel, or convergent neutron beams. Ray tracing simulations of the system (with source-object separation of 10m for 5 meV neutrons) show nearly an order of magnitude neutron flux increase on a 1-mm diameter object. The technology is a result of joint development efforts between NASA and MIT researchers seeking to maximize neutron flux from diffuse sources for imaging and testing applications.

Nabors, Sammy A.

2015-01-01

46

Radio-isotope production using laser Wakefield accelerators  

SciTech Connect

A 10 Hz, 10 TW solid state laser system has been used to produce electron beams suitable for radio-isotope production. The laser beam was focused using a 30 cm focal length f/6 off-axis parabola on a gas plume produced by a high pressure pulsed gas jet. Electrons were trapped and accelerated by high gradient wakefields excited in the ionized gas through the self-modulated laser wakefield instability. The electron beam was measured to contain excesses of 5 nC/bunch. A composite Pb/Cu target was used to convert the electron beam into gamma rays which subsequently produced radio-isotopes through (gamma, n) reactions. Isotope identification through gamma-ray spectroscopy and half-life time measurements demonstrated that Cu{sup 61} was produced which indicates that 20-25 MeV gamma rays were produced, and hence electrons with energies greater than 25-30 MeV. The production of high energy electrons was independently confirmed using a bending magnet spectrometer. The measured spectra had an exponential distribution with a 3 MeV width. The amount of activation was on the order of 2.5 uCi after 3 hours of operation at 1 Hz. Future experiments will aim at increasing this yield by post-accelerating the electron beam using a channel guided laser wakefield accelerator.

Leemans, W.P.; Rodgers, D.; Catravas, P.E.; Geddes, C.G.R.; Fubiani, G.; Toth, C.; Esarey, E.; Shadwick, B.A.; Donahue, R.; Smith, A.; Reitsma, A.

2001-07-27

47

International workshop on cold neutron sources  

SciTech Connect

The first meeting devoted to cold neutron sources was held at the Los Alamos National Laboratory on March 5--8, 1990. Cosponsored by Los Alamos and Oak Ridge National Laboratories, the meeting was organized as an International Workshop on Cold Neutron Sources and brought together experts in the field of cold-neutron-source design for reactors and spallation sources. Eighty-four people from seven countries attended. Because the meeting was the first of its kind in over forty years, much time was spent acquainting participants with past and planned activities at reactor and spallation facilities worldwide. As a result, the meeting had more of a conference flavor than one of a workshop. The general topics covered at the workshop included: Criteria for cold source design; neutronic predictions and performance; energy deposition and removal; engineering design, fabrication, and operation; material properties; radiation damage; instrumentation; safety; existing cold sources; and future cold sources.

Russell, G.J.; West, C.D. (comps.) (Los Alamos National Lab., NM (United States)) [comps.; Los Alamos National Lab., NM (United States)

1991-08-01

48

Cyclotron-based neutron source for BNCT  

NASA Astrophysics Data System (ADS)

Kyoto University Research Reactor Institute (KURRI) and Sumitomo Heavy Industries, Ltd. (SHI) have developed a cyclotron-based neutron source for Boron Neutron Capture Therapy (BNCT). It was installed at KURRI in Osaka prefecture. The neutron source consists of a proton cyclotron named HM-30, a beam transport system and an irradiation & treatment system. In the cyclotron, H- ions are accelerated and extracted as 30 MeV proton beams of 1 mA. The proton beams is transported to the neutron production target made by a beryllium plate. Emitted neutrons are moderated by lead, iron, aluminum and calcium fluoride. The aperture diameter of neutron collimator is in the range from 100 mm to 250 mm. The peak neutron flux in the water phantom is 1.8109 neutrons/cm2/sec at 20 mm from the surface at 1 mA proton beam. The neutron source have been stably operated for 3 years with 30 kW proton beam. Various pre-clinical tests including animal tests have been done by using the cyclotron-based neutron source with 10B-p-Borono-phenylalanine. Clinical trials of malignant brain tumors will be started in this year.

Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Ogasawara, T.; Fujita, K.; Tanaka, H.; Sakurai, Y.; Maruhashi, A.

2013-04-01

49

Cyclotron-based neutron source for BNCT  

SciTech Connect

Kyoto University Research Reactor Institute (KURRI) and Sumitomo Heavy Industries, Ltd. (SHI) have developed a cyclotron-based neutron source for Boron Neutron Capture Therapy (BNCT). It was installed at KURRI in Osaka prefecture. The neutron source consists of a proton cyclotron named HM-30, a beam transport system and an irradiation and treatment system. In the cyclotron, H- ions are accelerated and extracted as 30 MeV proton beams of 1 mA. The proton beams is transported to the neutron production target made by a beryllium plate. Emitted neutrons are moderated by lead, iron, aluminum and calcium fluoride. The aperture diameter of neutron collimator is in the range from 100 mm to 250 mm. The peak neutron flux in the water phantom is 1.8 Multiplication-Sign 109 neutrons/cm{sup 2}/sec at 20 mm from the surface at 1 mA proton beam. The neutron source have been stably operated for 3 years with 30 kW proton beam. Various pre-clinical tests including animal tests have been done by using the cyclotron-based neutron source with {sup 10}B-p-Borono-phenylalanine. Clinical trials of malignant brain tumors will be started in this year.

Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Ogasawara, T.; Fujita, K. [Sumitomo Heavy Industries, Ltd (Japan); Tanaka, H.; Sakurai, Y.; Maruhashi, A. [Kyoto University Research Reactor Institute (Japan)

2013-04-19

50

Neutron fan beam source for neutron radiography purpose  

SciTech Connect

The development of the DIANE neutron radiography system included a sealed-tube neutron generator for this purpose and the optimization of the system's neutron beam quality in terms of divergence and useful thermal neutron yield for each 14-MeV neutron produced. Following this development, the concept of a DIANE fan beam source is herewith introduced. The goal which drives this design is one of economy: by simply increasing the aperture dimension of a conventional DIANE beam in one plane of its collimator axis to a small-angle, fan-shaped output, the useful beam area for neutron radiography would be substantially increased. Thus with the same source, the throughput, or number of objects under examination at any given time, would be augmented significantly. Presented here are the design of this thermal neutron source and the initial Monte Carlo calculations. Taking into account the experience with the conventional DIANE neutron radiography system, these result are discussed and the potential of and interest in such a fan-beam source are explored.

Le Tourneur, P.; Bach, P.; Dance, W. E. [SODERN, 20, avenue Descartes, 94451 Limeil Brevannes (France); Consultant, Dallas, Texas (United States)

1999-06-10

51

Neutron dosimetry at SLAC: Neutron sources and instrumentation  

SciTech Connect

This report summarizes in detail the dosimetric characteristics of the five radioisotopic type neutron sources ({sup 238}PuBe, {sup 252}Cf, {sup 238}PuB, {sup 238}PuF{sub 4}, and {sup 238}PuLi) and the neutron instrumentation (moderated BF{sub 3} detector, Anderson-Braun (AB) detector, AB remmeter, Victoreen 488 Neutron Survey Meter, Beam Shut-Off Ionization Chamber, {sup 12}C plastic scintillator detector, moderated indium foil detector, and moderated and bare TLDs) that are commonly used for neutron dosimetry at the Stanford Linear Accelerator Center (SLAC). 36 refs,. 19 figs.

Liu, J.C.; Jenkins, T.M.; McCall, R.C.; Ipe, N.E.

1991-10-01

52

10 CFR 39.55 - Tritium neutron generator target sources.  

Code of Federal Regulations, 2010 CFR

...false Tritium neutron generator target sources. 39...Section 39.55 Energy NUCLEAR REGULATORY COMMISSION...55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target source,...

2010-01-01

53

10 CFR 39.55 - Tritium neutron generator target sources.  

Code of Federal Regulations, 2011 CFR

...false Tritium neutron generator target sources. 39...Section 39.55 Energy NUCLEAR REGULATORY COMMISSION...55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target source,...

2011-01-01

54

10 CFR 39.55 - Tritium neutron generator target sources.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Tritium neutron generator target sources. 39.55 Section...Equipment 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target source, containing...

2012-01-01

55

10 CFR 39.55 - Tritium neutron generator target sources.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Tritium neutron generator target sources. 39.55 Section...Equipment 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target source, containing...

2013-01-01

56

10 CFR 39.55 - Tritium neutron generator target sources.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 false Tritium neutron generator target sources. 39.55 Section...Equipment 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target source, containing...

2014-01-01

57

Neutronic design for ESS-Bilbao neutron source  

NASA Astrophysics Data System (ADS)

The European Spallation Source-Bilbao (ESS-Bilbao) project plans to build an accelerator facility compliant with the ESS-AB requirements which will be able to drive several experimental stations for research purposes involving intense proton beams with currents up to 75 mA, 50 MeV of final energy, 1.5 ms of pulse length and up to 50 Hz repetition rate. The accelerator will also drive a compact neutron source which will provide useful neutron beams to carry out experiments on moderator optimization, neutron optics devices and general neutron instrumentation as well as preparation work for experiments to be carried out by neutron beam users at the large facilities.

Sordo, F.; Terrn, S.; Magn, M.; Muhrer, G.; Ghiglino, A.; Martnez, F.; de Vicente, P. J.; Vivanco, R.; Perlado, J. M.; Bermejo, F. J.

2013-04-01

58

External Source Effects and Neutronics in Accelerator-driven Systems  

E-print Network

External Source Effects and Neutronics in Accelerator-driven Systems Per Seltborg Licentiate Thesis the MUSE (MUltiplication of External Source) program. In these experiments, an intense external neutron; the neutron energy spectrum, the external neutron source efficiency (*) and the dynamic neutron source

Haviland, David

59

Advanced Neutron Source (ANS) Project progress report  

SciTech Connect

This report discusses the following topics on the advanced neutron source: quality assurance (QA) program; reactor core development; fuel element specification; corrosion loop tests and analyses; thermal-hydraulic loop tests; reactor control concepts; critical and subcritical experiments; material data, structural tests, and analysis; cold source development; beam tube, guide, and instrument development; hot source development; neutron transport and shielding; I C research and development; facility concepts; design; and safety.

McBee, M.R.; Chance, C.M. (eds.) (Oak Ridge National Lab., TN (USA)); Selby, D.L.; Harrington, R.M.; Peretz, F.J. (Oak Ridge National Lab., TN (USA))

1990-04-01

60

Modulating the Neutron Flux from a Mirror Neutron Source  

SciTech Connect

A 14-MeV neutron source based on a Gas-Dynamic Trap will provide a high flux of 14 MeV neutrons for fusion materials and sub-component testing. In addition to its main goal, the source has potential applications in condensed matter physics and biophysics. In this report, the author considers adding one more capability to the GDT-based neutron source, the modulation of the neutron flux with a desired frequency. The modulation may be an enabling tool for the assessment of the role of non-steady-state effects in fusion devices as well as for high-precision, low-signal basic science experiments favoring the use of the synchronous detection technique. A conclusion is drawn that modulation frequency of up to 1 kHz and modulation amplitude of a few percent is achievable. Limitations on the amplitude of modulations at higher frequencies are discussed.

Ryutov, D D

2011-09-01

61

Inertial electrostatic confinement (IEC) neutron sources  

SciTech Connect

Inertial electrostatic confinement (IEC) is one of the earliest plasma confinement concepts, having first been suggested by P.T. Farnsworth in the 1950s. The concept involves a simple apparatus of concentric spherical electrostatic grids or a combination of grids and magnetic fields. An electrostatic structure is formed from the confluence of electron or ion beams. Gridded IEC systems have demonstrated neutron yields as high as 2 x 10(exp 10) neutrons/sec in steady state. These systems have considerable potential as small, inexpensive, portable neutron sources for assaying applications. Neutron tomography is also a potential application. This paper discusses the IEC concept and how it can be adapted to a steady-state assaying source and an intense pulsed neutron source. Theoretical modeling and experimental results are presented.

Barnes, D.C.; Caramana, E.J.; Janssen, R.D.; Nystrom, W.D.; Tiouririne, T.N.; Trent, B.C.; Miley, G.H.; Javedani, J.

1995-01-01

62

Inertial electrostatic confinement (IEC) neutron sources  

SciTech Connect

Inertial Electrostatic Confinement (IEC) is one of the earliest plasma confinement concepts, having first been suggested by P.T. Farnsworth in the 1950s. The concept involves a simple apparatus of concentric spherical electrostatic grids or a combination of grids and magnetic fields. An electrostatic structure is formed from the confluence of electron or ion beams. Gridded IEC systems have demonstrated neutron yields as high as 2 {times} 10{sup 10} neutrons/sec in steady state. These systems have considerable potential as small, inexpensive, portable neutron sources for assaying applications. Neutron tomography is also a potential application. This paper discusses the IEC concept and how it can be adapted to a steady-state assaying source and an intense pulsed neutron source. Theoretical modeling and experimental results are presented.

Nebel, R.A.; Barnes, D.C.; Caramana, E.J.; Janssen, R.D.; Nystrom, W.D.; Tiouririne, T.N.; Trent, B.C. [Los Alamos National Lab., NM (United States); Miley, G.H.; Javedani, J. [Univ. of Illinois, Urbana, IL (United States)

1995-12-31

63

High Brightness Neutron Source for Radiography  

Microsoft Academic Search

This research and development program was designed to improve nondestructive evaluation of large mechanical objects by providing both fast and thermal neutron sources for radiography. Neutron radiography permits inspection inside objects that x-rays cannot penetrate and permits imaging of corrosion and cracks in low-density materials. Discovering of fatigue cracks and corrosion in piping without the necessity of insulation removal is

J. T. Cremer; Piestrup; A. Melvin; K. Charles; Jack Harris; David L. Williams; Glenn Jones; J. Vainionpaa; Fuller; J. Michael; Rothbart; H. George; J. Kwan; B. Ludewigt; Gough; Jani Reijonen; Ka-Ngo Leung

2008-01-01

64

Quantitative NDA of isotopic neutron sources.  

PubMed

A non-destructive method for assaying transuranic neutron sources was developed, using a combination of gamma-spectrometry and neutron correlation technique. Source strength or actinide content of a number of PuBe, AmBe, AmLi, (244)Cm, and (252)Cf sources was assessed, both as a safety issue and with respect to combating illicit trafficking. A passive neutron coincidence collar was designed with (3)He counters embedded in a polyethylene moderator (lined with Cd) surrounding the sources to be measured. The electronics consist of independent channels of pulse amplifiers and discriminators as well as a shift register for coincidence counting. The neutron output of the sources was determined by gross neutron counting, and the actinide content was found out by adopting specific spontaneous fission and (alpha,n) reaction yields of individual isotopes from the literature. Identification of an unknown source type and constituents can be made by gamma-spectrometry. The coincidences are due to spontaneous fission in the case of Cm and Cf sources, while they are mostly due to neutron-induced fission of the Pu isotopes (i.e. self-multiplication) and the (9)Be(n,2n)(8)Be reaction in Be-containing sources. Recording coincidence rate offers a potential for calibration, exploiting a correlation between the Pu amount and the coincidence-to-total ratio. The method and the equipment were tested in an in-field demonstration exercise, with participation of national public authorities and foreign observers. Seizure of the illicit transport of a PuBe source was simulated in the exercise, and the Pu content of the source was determined. It is expected that the method could be used for identification and assay of illicit, found, or not documented neutron sources. PMID:15996474

Lakosi, L; Nguyen, C T; Bagi, J

2005-01-01

65

Cryogenic hydrogen circulation system of neutron source  

SciTech Connect

Cold neutron sources of reactors and spallation neutron sources are classic high flux neutron sources in operation all over the world. Cryogenic fluids such as supercritical or supercooled hydrogen are commonly selected as a moderator to absorb the nuclear heating from proton beams. By comparing supercritical hydrogen circulation systems and supercooled hydrogen circulation systems, the merits and drawbacks in both systems are summarized. When supercritical hydrogen circulates as the moderator, severe pressure fluctuations caused by temperature changes will occur. The pressure control system used to balance the system pressure, which consists of a heater as an active controller for thermal compensation and an accumulator as a passive volume controller, is preliminarily studied. The results may provide guidelines for design and operation of other cryogenic hydrogen system for neutron sources under construction.

Qiu, Y. N. [Institute of Physics and Chemistry, Chinese Academy of Sciences, BJ100190 China and University of Chinese Academy of Sciences, Chinese Academy of Sciences, BJ100049 (China); Hu, Z. J.; Wu, J. H.; Li, Q.; Zhang, Y. [Institute of Physics and Chemistry, Chinese Academy of Sciences, BJ100190 (China); Zhang, P. [School of Energy and Power Engineering, HuaZhong University of Science and Technology, WH430074 (China); Wang, G. P. [Institute of High Energy Physics, Chinese Academy of Sciences, BJ100049 (China)

2014-01-29

66

Cryogenic hydrogen circulation system of neutron source  

NASA Astrophysics Data System (ADS)

Cold neutron sources of reactors and spallation neutron sources are classic high flux neutron sources in operation all over the world. Cryogenic fluids such as supercritical or supercooled hydrogen are commonly selected as a moderator to absorb the nuclear heating from proton beams. By comparing supercritical hydrogen circulation systems and supercooled hydrogen circulation systems, the merits and drawbacks in both systems are summarized. When supercritical hydrogen circulates as the moderator, severe pressure fluctuations caused by temperature changes will occur. The pressure control system used to balance the system pressure, which consists of a heater as an active controller for thermal compensation and an accumulator as a passive volume controller, is preliminarily studied. The results may provide guidelines for design and operation of other cryogenic hydrogen system for neutron sources under construction.

Qiu, Y. N.; Hu, Z. J.; Wu, J. H.; Li, Q.; Zhang, Y.; Zhang, P.; Wang, G. P.

2014-01-01

67

Characteristics of low energy accelerator neutron sources  

SciTech Connect

Energy and fluence monitors are recommended for D-D and D-T neutrons. Neutron flux density spectra were determined for extended samples using the foil activation and physical integration methods. The unfolding method was checked by TOF and pulse height response spectrometers. Signal-to-background ratio was optimized for D-D gas cell neutron sources. Results show that the contribution of Coulomb breakup neutrons from the beam stop materials to the background is dominant at incident deuteron energies below 10 MeV.

Csikai, J.; Grallert, A.; Olah, L. [Kossuth Univ., Debrecen (Hungary); Qaim, S.M. [Institut fuer Nuklearchemie, Juelich (Germany)

1994-12-31

68

Californium-252: A New Isotopic Source for Neutron Radiography  

SciTech Connect

This report discusses a new isotopic source for neutron radiography, Californium-252. Nuclear reactors are the usual source of neutrons for radiography, primarily because of their intense neutron beams. If neutron radiography is to have widespread use, intense transportable neutron sources are required that can be used in plants, in laboratories and in the field.

Reinig, W.C.

2001-08-29

69

Spallation neutron source target station issues  

Microsoft Academic Search

In many areas of physics, materials and nuclear engineering, it is extremely valuable to have a very intense source of neutrons so that the structure and function of materials can be studied. One facility proposed for this purpose is the National Spallation Neutron Source (NSNS). This facility will consist of two parts: (1) a high-energy (1 GeV) and high powered

Tony A. Gabriel; John N. Barnes; Lowell A. Charlton

1996-01-01

70

Pulsed thermal neutron source at the fast neutron generator.  

PubMed

A small pulsed thermal neutron source has been designed based on results of the MCNP simulations of the thermalization of 14 MeV neutrons in a cluster-moderator which consists of small moderating cells decoupled by an absorber. Optimum dimensions of the single cell and of the whole cluster have been selected, considering the thermal neutron intensity and the short decay time of the thermal neutron flux. The source has been built and the test experiments have been performed. To ensure the response is not due to the choice of target for the experiments, calculations have been done to demonstrate the response is valid regardless of the thermalization properties of the target. PMID:19223189

Tracz, Grzegorz; Drozdowicz, Krzysztof; Gaba?ska, Barbara; Krynicka, Ewa

2009-06-01

71

High Brightness Neutron Source for Radiography  

SciTech Connect

This research and development program was designed to improve nondestructive evaluation of large mechanical objects by providing both fast and thermal neutron sources for radiography. Neutron radiography permits inspection inside objects that x-rays cannot penetrate and permits imaging of corrosion and cracks in low-density materials. Discovering of fatigue cracks and corrosion in piping without the necessity of insulation removal is possible. Neutron radiography sources can provide for the nondestructive testing interests of commercial and military aircraft, public utilities and petrochemical organizations. Three neutron prototype neutron generators were designed and fabricated based on original research done at the Lawrence Berkeley National Laboratory (LBNL). The research and development of these generators was successfully continued by LBNL and Adelphi Technology Inc. under this STTR. The original design goals of high neutron yield and generator robustness have been achieved, using new technology developed under this grant. In one prototype generator, the fast neutron yield and brightness was roughly 10 times larger than previously marketed neutron generators using the same deuterium-deuterium reaction. In another generator, we integrate a moderator with a fast neutron source, resulting in a high brightness thermal neutron generator. The moderator acts as both conventional moderator and mechanical and electrical support structure for the generator and effectively mimics a nuclear reactor. In addition to the new prototype generators, an entirely new plasma ion source for neutron production was developed. First developed by LBNL, this source uses a spiral antenna to more efficiently couple the RF radiation into the plasma, reducing the required gas pressure so that the generator head can be completely sealed, permitting the possible use of tritium gas. This also permits the generator to use the deuterium-tritium reaction to produce 14-MeV neutrons with increases of yield of two orders of magnitude. The first fast neutron radiographic images were obtained using neutron cameras and a new fast neutron generator. These early images demonstrated the feasibility of using fast neutrons for imaging and penetrating thick objects of high density and imaging. Fast neutrons can be used to image low atomic number materials (e.g. plastics, explosives, lubricants and ceramics) that are shielded by high density materials (e.g. lead, tungsten and uranium). Fast neutron radiography could be used as a means to screen weapons for flaws and chemical stability. X-ray radiography can not easily do this. Fast neutron imaging is technically difficult and, consequently, a completely undeveloped market. Two of the generators were designed to have small source size and high brightness, ideal for fast-neutron imaging. With these generators we successfully used two fast neutron cameras: one developed by us, and another developed by a collaborator, Commonwealth Scientific and Industrial Research Organization, CSIRO. We have successfully used these cameras to obtain low resolution images of various objects such as pipe fittings filled with water and other mechanical objects. Higher resolution and contrast images are expected by decreasing the source size and increasing generator yield.

Cremer, J. T.; Piestrup, Melvin, A.; Gary, Charles, K.; Harris, Jack, L. Williams, David, J.; Jones, Glenn, E.; Vainionpaa, J. , H.; Fuller, Michael, J.; Rothbart, George, H.; Kwan, J., W.; Ludewigt, B., A.; Gough, R.., A..; Reijonen, Jani; Leung, Ka-Ngo

2008-12-08

72

Directional detection of a neutron source  

SciTech Connect

Advantages afforded by the development of new directional neutron detectors and imagers are discussed. Thermal neutrons have mean free paths in air of about 20 meters, and can be effectively imaged using coded apertures. Fission spectrum neutrons have ranges greater than 100 meters, and carry enough energy to scatter at least twice in multilayer detectors which can yield both directional and spectral information. Such strategies allow better discrimination between a localized spontaneous fission source and the low, but fluctuating, level of background neutrons generated by cosmic rays. A coded aperture thermal neutron imager will be discussed as well as a proton-recoil double-scatter fast-neutron directional detector with time-of-flight energy discrimination. (authors)

Vanier, P. E. [Brookhaven National Laboratory, Bldg. 197C, Upton, NY 11973 (United States); Forman, L. [Ion Focus Technology, 52 Pardam Knoll, Miller Place, 11764 (United States)

2006-07-01

73

An Accelerator Neutron Source for BNCT  

SciTech Connect

The overall goal of this project was to develop an accelerator-based neutron source (ABNS) for Boron Neutron Capture Therapy (BNCT). Specifically, our goals were to design, and confirm by measurement, a target assembly and a moderator assembly that would fulfill the design requirements of the ABNS. These design requirements were 1) that the neutron field quality be as good as the neutron field quality for the reactor-based neutron sources for BNCT, 2) that the patient treatment time be reasonable, 3) that the proton current required to treat patients in reasonable times be technologially achievable at reasonable cost with good reliability, and accelerator space requirements which can be met in a hospital, and finally 4) that the treatment be safe for the patients.

Blue, Thomas, E

2006-03-14

74

Phenomenological calculations of shielding spallation neutron sources  

NASA Astrophysics Data System (ADS)

The high level of radiation generated by a spallation source requires the design of an appropriate shielding to surround the source in order to fulfill radiation protection standards. A calculation of the spallation neutron attenuation is presented for various shielding materials, using a phenomenological model, based on the Moyer model. In the first step of the calculation, the interaction length of neutrons for each neutron energy and shielding material was estimated using inelastic cross-sections. In the second step the calculation deals with the attenuation of the neutron flux applying the Moyer model, for each material and neutron energy region. The transmission factors were calculated and compared with experimental data collected from the "Gamma-2" and the "E+T" projects running in JINR (Dubna, Russia). The results of the present work were also compared to the data obtained by different Monte Carlo codes such as MORSE, MCNPX, MARS14 and LAHET.

Fragopoulou, M.; Zamani, M.

2013-06-01

75

Novae, supernovae, and neutron sources  

NASA Technical Reports Server (NTRS)

The evolution of thermonuclear runaways is examined in two models of white dwarfs with extreme enhancements of C-12 in their envelopes to test the predictions of Hoyle and Clayton (1974) that novae will result from such stars and a large neutron flux will be produced. In agreement with these predictions, it is assumed that the large amount of C-12 is due to the accretion of hydrogen-rich material from a disk surrounding a carbon-oxygen white dwarf. The evolution of the two models is described in detail, and the results suggest that accretion of hydrogen-rich material will always result in a thermonuclear runaway, although mass ejection will not occur unless CNO nuclei are enhanced. It is noted that one model produces a substantial neutron flux for a short time which is sufficient to drive an intermediate neutron-capture process.

Starrfield, S.; Truran, J. W.; Sparks, W. M.

1975-01-01

76

Studies of D-Li neutron source: An overview  

Microsoft Academic Search

The construction of a neutron source facility able to reproduce the radiation environment predicted for a fusion reactor can be considered a very important milestone for the fusion program. Such a neutron source should allow materials testing over a wide range of neutron flux and neutron fluence. To date, none of the existing facilities reproduce the neutron flux with the

I. Gomes; D. L. Smith

1994-01-01

77

Cryogenic System for the Spallation Neutron Source  

Microsoft Academic Search

The Spallation Neutron Source (SNS) is a neutron-scattering facility being built at Oak Ridge, TN for the US Department of Energy. The SNS accelerator linac consists of superconducting radio-frequency (SRF) cavities in cryostats (cryomodules). The linac cryomodules are cooled to 2.1 K by a 2300 watt cryogenic refrigeration system. As an SNS partner laboratory, Jefferson Lab is responsible for the

D. Arenius; W. Chronis; J. Creel; K. Dixon; V. Ganni; P. Knudsen

2004-01-01

78

Neutron science opportunities at pulsed spallation neutron sources  

SciTech Connect

Using the IPNS Upgrade plan developed at Argonne National Laboratory as a worked example of the design of a pulsed spallation neutron source, this paper explores some of the scientific applications of an advanced facility for materials science studies and the instrumentation for those purposes.

Carpenter, J.M. [Argonne National Lab., IL (United States). Intense Pulsed Neutron Source

1996-12-31

79

Z-pinch plasma neutron sources  

SciTech Connect

A deuterium gas-puff load imploded by a multi-MA current driver from a large initial diameter could be a powerful source of fusion neutrons, a plasma neutron source (PNS). Unlike the beam-target neutrons produced in Z-pinch plasmas in the 1950s and deuterium-fiber experiments in the 1980s, the neutrons generated in deuterium gas-puffs with current levels achieved in recent experiments on the Z facility at Sandia National Laboratories could contain a substantial fraction of thermonuclear origin. For recent deuterium gas-puff shots on Z, our analytic estimates and one- and two-dimensional simulations predict thermal neutron yields {approx}3x10{sup 13}, in fair agreement with the yields recently measured on Z [C. A. Coverdale et al., Phys. Plasmas (to be published)]. It is demonstrated that the hypothesis of a beam-target origin of the observed fusion neutrons implies a very high Z-pinch-driver-to-fast-ions energy transfer efficiency, 5 to 10%, which would make a multi-MA deuterium Z-pinch the most efficient light-ion accelerator. No matter what mechanism is eventually determined to be responsible for generating fusion neutrons in deuterium gas-puff shots on Z, the deuterium neutron yield is shown to scale as Y{sub n}{approx}I{sub m}{sup 4}, where I{sub m} is the peak current of the pinch. Theoretical estimates and numerical modeling of deuterium gas-puff implosions demonstrate that the yields of thermonuclear fusion neutrons that can be produced on ZR and the next-generation machines are sufficiently high to make PNS the most powerful, cost- and energy-efficient laboratory sources of 2.5-14 MeV fusion neutrons, just like plasma radiation sources are the most powerful sources of soft and keV x rays. In particular, the predicted deuterium-tritium thermal neutron-producing capability of PNS driven by the next-generation ZR and ZX accelerators is {approx}5x10{sup 16} and {approx}10{sup 18}, respectively.

Velikovich, A. L.; Clark, R. W.; Davis, J.; Chong, Y. K.; Deeney, C.; Coverdale, C. A.; Ruiz, C. L.; Cooper, G. W.; Nelson, A. J.; Franklin, J.; Rudakov, L. I. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Chemical and Nuclear Engineering Department, University of New Mexico, Albuquerque, New Mexico 87131 (United States); Ktech Corporation, Albuquerque, New Mexico 87185 (United States); Icarus Research, Inc., Bethesda, Maryland 20824-0780 (United States)

2007-02-15

80

Z-pinch plasma neutron sources  

NASA Astrophysics Data System (ADS)

A deuterium gas-puff load imploded by a multi-MA current driver from a large initial diameter could be a powerful source of fusion neutrons, a plasma neutron source (PNS). Unlike the beam-target neutrons produced in Z-pinch plasmas in the 1950s and deuterium-fiber experiments in the 1980s, the neutrons generated in deuterium gas-puffs with current levels achieved in recent experiments on the Z facility at Sandia National Laboratories could contain a substantial fraction of thermonuclear origin. For recent deuterium gas-puff shots on Z, our analytic estimates and one- and two-dimensional simulations predict thermal neutron yields 31013, in fair agreement with the yields recently measured on Z [C. A. Coverdale et al., Phys. Plasmas (to be published)]. It is demonstrated that the hypothesis of a beam-target origin of the observed fusion neutrons implies a very high Z-pinch-driver-to-fast-ions energy transfer efficiency, 5 to 10%, which would make a multi-MA deuterium Z-pinch the most efficient light-ion accelerator. No matter what mechanism is eventually determined to be responsible for generating fusion neutrons in deuterium gas-puff shots on Z, the deuterium neutron yield is shown to scale as YnIm4, where Im is the peak current of the pinch. Theoretical estimates and numerical modeling of deuterium gas-puff implosions demonstrate that the yields of thermonuclear fusion neutrons that can be produced on ZR and the next-generation machines are sufficiently high to make PNS the most powerful, cost- and energy-efficient laboratory sources of 2.5-14MeV fusion neutrons, just like plasma radiation sources are the most powerful sources of soft and keV x rays. In particular, the predicted deuterium-tritium thermal neutron-producing capability of PNS driven by the next-generation ZR and ZX accelerators is 51016 and 1018, respectively.

Velikovich, A. L.; Clark, R. W.; Davis, J.; Chong, Y. K.; Deeney, C.; Coverdale, C. A.; Ruiz, C. L.; Cooper, G. W.; Nelson, A. J.; Franklin, J.; Rudakov, L. I.

2007-02-01

81

A neutron producing target for BINP accelerator-based neutron source B. Bayanova  

E-print Network

A neutron producing target for BINP accelerator-based neutron source B. Bayanova , E. Kashaeva b l e i n f o Keywords: Target Lithium Neutron capture therapy Epithermal neutrons a b s t r a c t An innovative accelerator-based neutron source for BNCT has just started operation at the Budker Institute

Taskaev, Sergey Yur'evich

82

THERMAL NEUTRON INTENSITIES IN SOILS IRRADIATED BY FAST NEUTRONS FROM POINT SOURCES. (R825549C054)  

EPA Science Inventory

Thermal-neutron fluences in soil are reported for selected fast-neutron sources, selected soil types, and selected irradiation geometries. Sources include 14 MeV neutrons from accelerators, neutrons from spontaneously fissioning 252Cf, and neutrons produced from alp...

83

Preliminary one-dimensional neutronics scoping study for a Californium-252 cold neutron source moderating device  

NASA Astrophysics Data System (ADS)

One-dimensional neutron transport calculations have been performed for a proposed Californium Cold Neutron Source experimental facility. The computations indicate that a peak cold neutron flux (flux below 10 meV) of 1.4 10 13 neutrons/m 2 s can be attained from a 500 mg californium neutron source. The cold neutron exit (leakage) current from the spherical cryostat containing the liquid deuterium is 2.2 10 12 neutrons/m 2 s.

Henderson, D. L.; Alsmiller, R. G.

1989-08-01

84

SUPERCONDUCTING LINAC FOR THE SPALLATION NEUTRON SOURCE  

SciTech Connect

The Spallation Neutron Source (SNS) linac is comprised of both normal and superconducting rf (SRF) accelerating structures. The SRF linac accelerates the beam from 186 to 1250 MeV through 117 elliptical, multi-cell niobium cavities. This paper describes the SRF linac architecture, physics design considerations, cavity commissioning, and the expected beam dynamics performance.

J. STOVALL; S. NATH; ET AL

2000-10-01

85

Superconducting cyclotron: neutron source for therapy  

Microsoft Academic Search

A neutron source for medical therapy purposes is described. The cyclotron consists of: an iron metal housing acting as a magnetic yoke, magnetic shield, radiation shield, and vacuum vessel; a pair of superconducting coils mounted in a cavity in the housing, the coils being cooled to superconducting temperatures; an ion orbiting region defined by pairs of sectoral-shaped rf electrode structures

C. B. Bigham; H. R. Schneider

1975-01-01

86

Secondary electron ion source neutron generator  

DOEpatents

A neutron generator employing an electron emitter, an ion source bombarded by the electrons from the electron emitter, a plasma containment zone, and a target situated between the plasma containment zone and the electron emitter is disclosed. The target contains occluded deuterium, tritium, or a mixture thereof. 4 figs.

Brainard, J.P.; McCollister, D.R.

1998-04-28

87

Secondary electron ion source neutron generator  

DOEpatents

A neutron generator employing an electron emitter, an ion source bombarded by the electrons from the electron emitter, a plasma containment zone, and a target situated between the plasma containment zone and the electron emitter. The target contains occluded deuterium, tritium, or a mixture thereof

Brainard, John P. (Albuquerque, NM); McCollister, Daryl R. (Albuquerque, NM)

1998-01-01

88

NEUTRON SOURCES FOR USE IN REACTOR STARTUP  

Microsoft Academic Search

The particular properties of the Westinghouse Testing Reactor are used ; in the design of the neutron sources to be used both in its startup and in the ; critical experiments. Specifically the WTR is a high flux irradiation facility ; using highly enriched U²³⁵ as fuel and light water as moderator and coolant. ; The amount of reactivity control

de Saint Maurice

1956-01-01

89

TRIUMF Ultra-cold Neutron Source Facility  

NASA Astrophysics Data System (ADS)

An ultra-cold neutron (UCN) source is planned for installation at TRIUMF, Canada, aiming to produce the world's highest density of UCNs using down-scattering of cold neutrons in superfluid helium. This project is a collaboration of Japan and Canada funded by JSPS (KEK) and CFI (University of Winnipeg). The first experiment using this UCN source will be the measurement of the electric dipole moment of the neutron (nEDM). Development of the UCN source and the prototype nEDM experiment will be done at RCNP, Japan in 2013-14. After that, the UCN source and the EDM apparatus will be moved and installed at TRIUMF. Beam commissioning is scheduled for 2015 and neutron EDM experiment is scheduled to start in 2016 at TRIUMF. The goal is to improve the current upper limit of nEDM of dn< 2.9x10-26e-cm by two order of magnitude at TRIUMF. An overview of the TRIUMF UCN facility including design of a new beam line, development of a spallation target, and re-configuring of the shielding arrangement will be presented in this talk.

Shin, Yun Chang

2012-10-01

90

Transmission Bragg edge spectroscopy measurements at ORNL Spallation Neutron Source  

Microsoft Academic Search

Results of neutron transmission Bragg edge spectroscopic experiments performed at the SNAP beamline of the Spallation Neutron Source are presented. A high resolution neutron counting detector with a neutron sensitive microchannel plate and Timepix ASIC readout is capable of energy resolved two dimensional mapping of neutron transmission with spatial accuracy of ~55 mum, limited by the readout pixel size, and

A. S. Tremsin; J. B. McPhate; J. V. Vallerga; O. H. W. Siegmund; W. B. Feller; H. Z. Bilheux; J. J. Molaison; C. A. Tulk; L. Crow; R. G. Cooper; D. Penumadu

2010-01-01

91

Neutron sources in nuclear astrophysics  

NASA Astrophysics Data System (ADS)

The excitations functions of the reactions 9Be((alpha) ,n)12C, 13C((alpha) ,n)16O, 17O((alpha) ,n)20Ne, 18O((alpha) ,n)21Ne, 21Ne((alpha) ,n)24Mg, 22Ne((alpha) ,n)25Mg, 25Mg((alpha) ,n)28Si and 26Mg((alpha) ,n)29Si have been measured at the 4 MV dynamitron accelerator in Stuttgart, Germany in the energy range of astrophysical interest, and from these S-factor- curves have been determined. Advanced techniques, especially with the windowless gastarget facility Rhinoceros have been applied. For neutron detection NE213 scintillation counters and a long counter like 4(pi) -detector have been used. A sensitivity limit in the range of 10-10b to 10-\\11b was reached with these experiments. Using our new experimental results astrophysical reaction rates have been calculated for all reactions except the Mg-reactions. Analytic expressions have been fitted to all reaction rates.

Kunz, Rino E.; Denker, A.; Drotleff, H. W.; Grosse, M.; Knee, H.; Kuechler, S.; Seidel, R.; Soine, M.; Hammer, J. W.

1995-03-01

92

Neutron source, neutron density and the origin of barium stars  

Microsoft Academic Search

The authors present new high resolution spectra of the MgH profiles in nine barium stars, and determine, by spectral synthesis techniques, the magnesium isotopic ratios in each star. When compared with recent AGB nucleosynthesis calculations, they can emphatically rule out the operation of the 22Ne(alpha, n)25Mg reaction as the neutron source responsible for the s-process enhancements observed in these barium

Robert A. Malaney; David L. Lambert

1988-01-01

93

Spallation neutron source and other high intensity froton sources  

SciTech Connect

This lecture is an introduction to the design of a spallation neutron source and other high intensity proton sources. It discusses two different approaches: linac-based and synchrotron-based. The requirements and design concepts of each approach are presented. The advantages and disadvantages are compared. A brief review of existing machines and those under construction and proposed is also given. An R&D program is included in an appendix.

Weiren Chou

2003-02-06

94

Portable, high intensity isotopic neutron source provides increased experimental accuracy  

NASA Technical Reports Server (NTRS)

Small portable, high intensity isotopic neutron source combines twelve curium-americium beryllium sources. This high intensity of neutrons, with a flux which slowly decreases at a known rate, provides for increased experimental accuracy.

Mohr, W. C.; Stewart, D. C.; Wahlgren, M. A.

1968-01-01

95

HIGH FLUENCE NEUTRON SOURCE FOR NONDESTRUCTIVE CHARACTERIZATION OF NUCLEAR WASTE  

EPA Science Inventory

We propose to research the basic plasma physics necessary to develop a high fluence neutron source based on the inertial electrostatically confined (IEC) plasma. An intense neutron source directly addresses the capability to characterize nuclear materials under difficult measurem...

96

Experience with position sensitive neutron detectors at the Intense Pulsed Neutron Source  

Microsoft Academic Search

At the Intense Pulsed Neutron Source (IPNS) pulses of protons accelerated in a synchrotron produce pulses of fast neutrons via the spallation process in an enriched uranium target. After moderation, the resulting pulses of slow neutrons are directed into beams which serve a variety of neutron scattering instruments. Currently there are thirteen neutron scattering instruments in operation or under development

R. K. Crawford; J. R. Haumann; A. J. Schultz; G. P. Felcher; J. E. Epperson; P. Thiyagarajan; D. G. Montague; R. J. Dejus

1990-01-01

97

Experience with position-sensitive neutron detectors at the Intense Pulsed Neutron Source  

Microsoft Academic Search

At the Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory, pulses of protons accelerated in a synchrotron produce pulses of fast neutrons via the spallation process in an enriched uranium target. After moderation, the resulting pulses of slow neutrons are directed into beams which serve a variety of neutron-scattering instruments. Currently there are thirteen neutron-scattering instruments in operation or

R. K. Crawford; J. R. Haumann; J. E. Epperson; P. Thiyagarajan; A. J. Schultz; G. P. Felcher; D. G. Montague; R. J. Dejus

1990-01-01

98

First neutron generation in the BINP accelerator based neutron source B. Bayanova  

E-print Network

First neutron generation in the BINP accelerator based neutron source B. Bayanova , A. Burdakova c l e i n f o Keywords: Epithermal neutrons Lithium target Neutron capture therapy Tandem accelerator a b s t r a c t Pilot innovative facility for neutron capture therapy was built at Budker

Taskaev, Sergey Yur'evich

99

neutron density. The neutron density (nn) of the source was modeled by solving the simul-  

E-print Network

neutron density. The neutron density (nn) of the source was modeled by solving the simul- taneousT is the thermal neutron velocity, l is the decay constant, Ns is the s-process abun- dance, bs? is the maxwellian-averaged neutron capture cross-section, and t0 is the average neutron exposure (21). The branching decay of 186Re

West, Stuart

100

Compact neutron source development at LBNL  

NASA Astrophysics Data System (ADS)

A compact neutron generator based on D-D or D-T fusion reactions is being developed at the Lawrence Berkeley National laboratory. The deuterium or tritium ions are produced in a radio-frequency (RF) driven multicusp plasma source. Seven beamlets are extracted and are accelerated to energy of 100 keV by means of a three-electrode electrostatic accelerator column. The ion beam then impinges on a titanium coated copper target where either the 2.4 MeV D-D or 13 MeV D-T neutrons are generated by fusion reaction. The development of the neutron tube is divided into three phases. First, the accelerator column is operated at hydrogen beam intensity of 15 mA. Second phase consists of deuterium beam runs at pulsed, low duty cycle 150 mA operation. The third phase consists of deuterium or tritium operation at 1.5 A beam current. Phase one is completed and the results of hydrogen beam testing are discussed. Low duty cycle 150 mA deuterium operation is being investigated. Neutron flux will be measured. Finally the phase three operation and the advance neutron generator designs are described.

Reijonen, Jani; Lou, Tak P.; Tolmachoff, Bryan; Leung, Ka-Ngo

2001-12-01

101

Neutron spin-echo spectrometer development for spallation sources  

Microsoft Academic Search

Neutron spin-echo spectrometers (NSE) are the neutron scattering instruments with the highest available energy resolution. Since new neutron sources like the ESS, SNS, JPNS will grow up in the next years one is interested to use those sources for a NSE. In this short report an overview of main challenges to adapt the existing NSE to spallation sources will be

M. Ohl; M. Monkenbusch; D. Richter

2003-01-01

102

Compact, inexpensive, epithermal neutron source for BNCT  

Microsoft Academic Search

A new rf-focused linac structure, designed specifically to increase the acceleration efficiency and reduce the cost of linac structures in the few-MeV range, may win the role as the optimum accelerator-based epithermal neutron source for the BNCT application. This new linac structure resembles a drift tube linac (DTL) with radio frequency quadrupole (RFQ) focusing incorporated into each drift tube, hence

D. A. Swenson

1999-01-01

103

Compact, inexpensive, epithermal neutron source for BNCT  

Microsoft Academic Search

A new rf-focused linac structure, designed specifically to increase the acceleration efficiency and reduce the cost of linac structures in the few-MeV range, may win the role as the optimum accelerator-based epithermal neutron source for the BNCT application. This new linac structure resembles a drift tube linac (DTL) with radio frequency quadrupole (RFQ) focusing incorporated into each ``drift tube,'' hence

D. A. Swenson

1999-01-01

104

Standard Neutron Sources. Bibliography No. 11; SOURCES ETALONS DE NEUTRONS. Bibliographie No. 11  

Microsoft Academic Search

Seventy-nine abstracts are presented on the methods and processes of ; neutron source calibration and the preparation and properties of standard sources. ; The abstracts are arranged chronologically and cover a period from l936 to 196l. ; (D.L.C.)

Desdevises

1961-01-01

105

Production, distribution and applications of californium-252 neutron sources  

Microsoft Academic Search

The radioisotope 252Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-yr half-life. A source the size of a persons little finger can emit up to 1011 neutrons s?1. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement and minerals, as well as for detection and

R. C. Martin; J. B. Knauer; P. A. Balo

2000-01-01

106

Experimental Neutron Source Facility Based on Accelerator Driven System  

NASA Astrophysics Data System (ADS)

An experimental neutron source facility has been developed for producing medical isotopes, training young nuclear professionals, providing capability for performing reactor physics, material research, and basic science experiments. It uses a driven subcritical assembly with an electron accelerator. The neutrons driving the subcritical assembly were generated from the electron interactions with a target assembly. Tungsten or uranium target material is used for the neutron production through photonuclear reactions. The neutron source intensity, spectrum, and spatial distribution have been studied to maximize the neutron yield and satisfy different engineering requirements. The subcritical assembly is designed to obtain the highest possible neutron flux intensity with a subcriticality of 0.98. Low enrichment uranium is used for the fuel material because it enhances the neutron source performance. Safety, reliability, and environmental considerations are included in the facility conceptual design. Horizontal neutron channels are incorporated for performing basic research including cold neutron source. This paper describes the conceptual design and summarizes some of the related analyses.

Gohar, Yousry

2010-06-01

107

Physics and technology of spallation neutron sources  

NASA Astrophysics Data System (ADS)

A substantial body of research is necessary in order to be able to make reliable predictions on the performance and safety of Accelerator Driven Systems (ADS), in particular of their spallation targets. So far, practical experience has resulted from the development of research neutron sources only. Next to fission and fusion, spallation is an efficient process for releasing neutrons from nuclei. Unlike the other two reactions, it is an endothermal process and can, therefore, not be used per se in energy generation. In order to sustain a spallation reaction, an energetic beam of particles, most commonly protons, must be supplied onto a heavy target. Spallation can, however, play an important role as a source of neutrons whose flux can be easily controlled via the driving beam. Although sophisticated Monte Carlo codes exist to compute all aspects of a spallation facility, many features can be understood on the basis of simple physics arguments. Technically a spallation facility is very demanding, not only because a reliable and economic accelerator of high power is needed to drive the reaction, but also, and in particular, because high levels of radiation and heat are generated in the target which are difficult to cope with. Radiation effects in a spallation environment are different from those commonly encountered in a reactor and are probably even more temperature dependent than the latter because of the high gas production rate. A commonly favored solution is the use of molten heavy metal targets. While radiation damage is not a problem in this case, except for the container, other issues need to be considered. R&D carried out for the development of spallation neutron sources will thus be beneficial also directly for ADS.

Bauer, G. S.

2001-05-01

108

Advanced Neutron Source: Plant Design Requirements  

SciTech Connect

The Advanced Neutron Source will be a new world-class facility for research using hot, thermal, cold, and ultra-cold neutrons. The heart of the facility will be a 330-MW (fission), heavy-water cooled and heavy-water moderated reactor. The reactor will be housed in a central reactor building, with supporting equipment located in an adjoining reactor support building. An array of cold neutron guides will fan out into a large guide hall, housing about 30 neutron research stations. Appropriate office, laboratory, and shop facilities will be included to provide a complete facility for users. The ANS is scheduled to begin operation at the Oak Ridge National Laboratory early in the next decade. This PDR document defines the plant-level requirements for the design, construction, and operation of ANS. It also defines and provides input to the individual System Design Description (SDD) documents. Together, this PDR document and the set of SDD documents will define and control the baseline configuration of ANS.

Not Available

1990-07-01

109

Unperturbed moderator brightness in pulsed neutron sources  

NASA Astrophysics Data System (ADS)

The unperturbed neutron brightness of a moderator can be defined from the number of neutrons leaving the surface of a moderator completely surrounded by a reflector. Without openings for beam extraction, it is the maximum brightness that can be theoretically achieved in a moderator. The unperturbed brightness of a cylindrical cold moderator filled with pure para-H2 was calculated using MCNPX; the moderator dimensions were optimised, for a fixed target and reflector geometry corresponding to the present concept for the ESS spallation source. This quantity does not depend on openings for beam extraction and therefore can be used for a first-round optimisation of a moderator, before effects due to beam openings are considered. We find that such an optimisation yields to a factor of 2 increase with respect to a conventional volume moderator, large enough to accommodate a viewed surface of 1212 cm2: the unperturbed neutron brightness is maximum for a disc-shaped moderator of 15 cm diameter, 1.4 cm height. The reasons for this increase can be related to the properties of the scattering cross-section of para-H2, to the added reflector around the exit surface in the case of a compact moderator, and to a directionality effect. This large optimisation gain in the unperturbed brightness hints towards similar potentials for the perturbed neutron brightness, in particular in conjunction with advancing the optical quality of neutron delivery from the moderator to the sample, where by Liouville theorem the brightness is conserved over the beam trajectory, except for absorption and similar type losses.

Batkov, K.; Takibayev, A.; Zanini, L.; Mezei, F.

2013-11-01

110

High electric field deuterium ion sources for neutron generators  

Microsoft Academic Search

Active interrogation systems for highly enriched uranium require improved fieldable neutron sources. The target technology for deuterium-tritium neutron generators is well understood and the most significant improvement can be achieved by improving the deuterium ion source through increased output and, in some cases, lifetime of the ion source. We are developing a new approach to a deuterium ion sources based

Birk Reichenbach

2009-01-01

111

Inertial electro-magnetostatic plasma neutron sources  

SciTech Connect

Two types of systems are being studied experimentally as D-T plasma neutron sources. In both concepts, spherical convergence of either electrons or ions or both is used to produce a dense central focus within which D-T fusion reactions produce 14 MeV neutrons. One concept uses nonneutral plasma confinement principles in a Penning type trap. In this approach, combined electrostatic and magnetic fields provide a vacuum potential well within which electrons are confined and focused. A small (6 mm radius) spherical machine has demonstrated a focus of 30 {micro}m radius, with a central density of up to 35 times the Brillouin density limit of a static trap. The resulting electron plasma of up to several 10{sup 13} cm{sup {minus}3} provides a multi-kV electrostatic well for confining thermonuclear ions as a neutron source. The second concept (Inertial Electrostatic Confinement, or IEC) uses a high-transparence grid to form a global well for acceleration and confinement of ions. Such a system has demonstrated steady neutron output of 2 {times} 10{sup 10} s{sup {minus}1}. The present experiment will scale this to >10{sup 11} s{sup {minus}1}. Advanced designs based on each concept have been developed recently. In these proposed approaches, a uniform-density electron sphere forms an electrostatic well for ions. Ions so trapped may be focused by spherical convergence to produce a dense core. An alternative approach produces large amplitude spherical oscillations of a confined ion cloud by a small, resonant modulation of the background electrons. In both the advanced Penning trap approach and the advanced IEC approach, the electrons are magnetically insulated from a large (up to 100 kV) applied electrostatic field. The physics of these devices is discussed, experimental design details are given, present observations are analyzed theoretically, and the performance of future advanced systems are predicted.

Barnes, D.C.; Nebel, R.A.; Schauer, M.M.; Pickrel, M.M. [Los Alamos National Lab., NM (United States)

1997-12-31

112

Superfluid-helium Ultracold Neutron Sources: Concepts for the European Spallation Source?  

NASA Astrophysics Data System (ADS)

Production of ultracold neutrons by conversion of cold neutrons in superfluid helium can be implemented in several ways, with the converter located either in-pile close to the core of a nuclear reactor or closely coupled to a neutron spallation source, or at the end of a neutron guide. This paper shall contribute to a discussion about source concepts for the ESS.

Zimmer, Oliver

113

Dual-mode operation of a neutron source, a concept  

NASA Technical Reports Server (NTRS)

Pulsed neutron source operates in conjunction with a photomultiplier tube coupled to a gamma ray scintillation crystal. This allows measurements of gamma radiation from both inelastic scattering and thermal neutron capture in a single experiment.

Givens, W. W.; Mills, W. R., Jr.

1969-01-01

114

New sources and instrumentation for neutrons in biology.  

PubMed

Neutron radiation offers significant advantages for the study of biological molecular structure and dynamics. A broad and significant effort towards instrumental and methodological development to facilitate biology experiments at neutron sources worldwide is reviewed. PMID:19132140

Teixeira, S C M; Ankner, J; Bellissent-Funel, M C; Bewley, R; Blakeley, M P; Coates, L; Dahint, R; Dalgliesh, R; Dencher, N; Dhont, J; Fischer, P; Forsyth, V T; Fragneto, G; Frick, B; Geue, T; Gilles, R; Gutberlet, T; Haertlein, M; Hau, T; Huler, W; Heller, W T; Herwig, K; Holderer, O; Juranyi, F; Kampmann, R; Knott, R; Kohlbrecher, J; Kreuger, S; Langan, P; Lechner, R; Lynn, G; Majkrzak, C; May, R; Meilleur, F; Mo, Y; Mortensen, K; Myles, D A A; Natali, F; Neylon, C; Niimura, N; Ollivier, J; Ostermann, A; Peters, J; Pieper, J; Rhm, A; Schwahn, D; Shibata, K; Soper, A K; Straessle, T; Suzuki, U-I; Tanaka, I; Tehei, M; Timmins, P; Torikai, N; Unruh, T; Urban, V; Vavrin, R; Weiss, K; Zaccai, G

2008-01-01

115

THE SPALLATION NEUTRON SOURCE PROJECT - PHYSICAL AND TECHNICAL CHALLENGES.  

SciTech Connect

The Spallation Neutron Source (SNS) is designed to reach an average proton beam power of 1.4 MW for pulsed neutron production. This paper summarizes design aspects and physical challenges to the project.

WEI,J.

2002-04-08

116

New sources and instrumentation for neutrons in biology  

PubMed Central

Neutron radiation offers significant advantages for the study of biological molecular structure and dynamics. A broad and significant effort towards instrumental and methodological development to facilitate biology experiments at neutron sources worldwide is reviewed. PMID:19132140

Teixeira, S.C.M.; Ankner, J.; Bellissent-Funel, M.C.; Bewley, R.; Blakeley, M.P.; Coates, L.; Dahint, R.; Dalgliesh, R.; Dencher, N.; Dhont, J.; Fischer, P.; Forsyth, V.T.; Fragneto, G.; Frick, B.; Geue, T.; Gilles, R.; Gutberlet, T.; Haertlein, M.; Hau, T.; Huler, W.; Heller, W.T.; Herwig, K.; Holderer, O.; Juranyi, F.; Kampmann, R.; Knott, R.; Kohlbrecher, J.; Kreuger, S.; Langan, P.; Lechner, R.; Lynn, G.; Majkrzak, C.; May, R.; Meilleur, F.; Mo, Y.; Mortensen, K.; Myles, D.A.A.; Natali, F.; Neylon, C.; Niimura, N.; Ollivier, J.; Ostermann, A.; Peters, J.; Pieper, J.; Rhm, A.; Schwahn, D.; Shibata, K.; Soper, A.K.; Straessle, T.; Suzuki, U.-i.; Tanaka, I.; Tehei, M.; Timmins, P.; Torikai, N.; Unruh, T.; Urban, V.; Vavrin, R.; Weiss, K.; Zaccai, G.

2008-01-01

117

Status of the intense pulsed neutron source  

SciTech Connect

Fortunately in spite of some premature reports of its impending demise, IPNS has passed the fourth anniversary of the first delivery of protons to the targets (May 5, 1981) and is approaching the fourth anniversary of its operation as a scattering facility (August 4, 1981). On June 10, 1984, the RCS delivered its one billionth pulse to the IPNS target - the total number of protons delivered to the targets amounted then to 75 stp cm/sup 3/ of H/sub 2/ gas. Since startup IPNS has improved steadily in terms of the performance of the Rapid Cycling Synchrotron, the source and its moderators and the scattering instruments, and a substantial and productive user program has evolved. This report summarizes the current status of the Intense Pulsed Neutron Source at Argonne National Laboratory. We include reference to recent accelerator operating experience, neutron facility operating experience, improvements to these systems, design work on the ASPUN high-current facility, booster target design, the new solid methane moderator, characterization of the room temperature moderators, and provide some examples of recent results from several of the spectrometers.

Carpenter, J.M.; Brown, B.S.; Kustom, R.L.; Lander, G.H.; Potts, C.W.; Schulke, A.W.; Wuestefeld, G.

1985-01-01

118

Field Ion Source Development for Neutron Generators  

SciTech Connect

An ion source based on the principles of electrostatic field desorption is being developed to improve the performance of existing compact neutron generators. The ion source is an array of gated metal tips derived from field electron emitter array microfabrication technology. A comprehensive summary of development and experimental activities is presented. Many structural modifications to the arrays have been incorporated to achieve higher tip operating fields, while lowering fields at the gate electrode to prevent gate field electron emission which initiates electrical breakdown in the array. The latest focus of fabrication activities has been on rounding the gate electrode edge and surrounding the gate electrode with dielectric material. Array testing results have indicated a steady progression of increased array tip operating fields with each new design tested. The latest arrays have consistently achieved fields beyond those required for the onset of deuterium desorption ({approx}20 V/nm), and have demonstrated the desorption of deuterium at fields up to 36 V/nm. The number of ions desorbed from an array has been quantified, and field desorption of metal tip substrate material from array tips has been observed for the first time. Gas-phase field ionization studies with {approx}10,000 tip arrays have achieved deuterium ion currents of {approx}50 nA. Neutron production by field ionization has yielded {approx}10{sup 2} n/s from {approx}1 mm{sup 2} of array area using the deuterium-deuterium fusion reaction at 90 kV.

B. Bargsten Johnson; P. R. Schwoebel; C. E. Holland; P. J. Resnick; K. L. Hertz; D. L. Chichester

2012-01-01

119

Using spallation neutron sources for defense research  

SciTech Connect

Advanced characterization techniques and accelerated simulation are the cornerstones of the Energy Department`s science-based program to maintain confidence in the safety, reliability, and performance of the US nuclear deterrent in an era of no nuclear testing. Neutrons and protons provided by an accelerator-based facility have an important role to play in this program, impacting several of the key stockpile stewardship and management issues identified by the Department of Defense. Many of the techniques used for defense research at a spallation source have been used for many years for the basic research community, and to a lesser extent by industrial scientists. By providing access to a broad spectrum of researchers with different backgrounds, a spallation source such as the Los Alamos Neutron Science Center is able to promote synergistic interaction between defense, basic and industrial researchers. This broadens the scientific basis of the stockpile stewardship program in the short term and will provide spin-off to industrial and basic research in the longer term.

Pynn, R.; Sterbenz, S.M.; Weinacht, D.J.

1996-12-31

120

Novel neutron focusing mirrors for compact neutron sources  

E-print Network

We demonstrated neutron beam focusing and neutron imaging using axisymmetric optics, based on pairs of confocal ellipsoid and hyperboloid mirrors. Such systems, known as Wolter mirrors, are commonly used in x-ray telescopes. ...

Gubarev, M.V.

121

Spallation Neutron Source Effects in a SubCritical System  

Microsoft Academic Search

Numerical simulations of a sub-critical system coupled to a neutron spallation source (1000 MeV protons impinging on a lead target) have been performed with the Monte Carlo code MCNPX and the deterministic code system ERANOS. The investigations have focused on the determination of the source neutron efficiency, ?*, i.e. the ratio of the average importance of external source neutrons to

P. Seltborg; R. Jacqmin

122

A cryogenic source for neutron radiography using a TRIGA reactor  

Microsoft Academic Search

A subthermal neutron radiographic facility has been established and successfully operated at General Atomic Company's TRIGA facility to interrogate materials exhibiting a Bragg edge in scattering cross section for neutrons below thermal energies. The facility makes use of the 1500 kW TRIGA Mark F as a neutron source, coupled to a moderator volume of solid methane maintained in the temperature

R. H. Chesworth; W. L. Whittemore

1980-01-01

123

HFIR cold neutron source moderator vessel design analysis  

SciTech Connect

A cold neutron source capsule made of aluminum alloy is to be installed and located at the tip of one of the neutron beam tubes of the High Flux Isotope Reactor. Cold hydrogen liquid of temperature approximately 20 degree Kelvin and 15 bars pressure is designed to flow through the aluminum capsule that serves to chill and to moderate the incoming neutrons produced from the reactor core. The cold and low energy neutrons thus produced will be used as cold neutron sources for the diffraction experiments. The structural design calculation for the aluminum capsule is reported in this paper.

Chang, S.J.

1998-04-01

124

Cryogenic System for the Spallation Neutron Source  

SciTech Connect

The Spallation Neutron Source (SNS) is a neutron-scattering facility being built at Oak Ridge, TN for the US Department of Energy. The SNS accelerator linac consists of superconducting radio-frequency (SRF) cavities in cryostats (cryomodules). The linac cryomodules are cooled to 2.1 K by a 2300 watt cryogenic refrigeration system. As an SNS partner laboratory, Jefferson Lab is responsible for the installed integrated cryogenic system design for the SNS linac accelerator consisting of major subsystem equipment engineered and procured from industry. Jefferson Lab's work included developing the major vendor subsystem equipment procurement specifications, equipment procurement, and the integrated system engineering support of the field installation and commissioning. The major cryogenic system components include liquid nitrogen storage, gaseous helium storage, cryogen distribution transfer line system, 2.1-K cold box consisting of four stages of cold compressors, 4.5-K cold box, warm helium compressors with its associated oil removal, gas management, helium purification, gas impurity monitoring systems, and the supportive utilities of electrical power, cooling water and instrument air. The system overview, project organization, the important aspects, and the capabilities of the cryogenic system are described.

Arenius, D.; Chronis, W.; Creel, J.; Dixon, K.; Ganni, V.; Knudsen, P. [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Avenue, Newport News, VA 23606 (United States)

2004-06-23

125

SPALLATION NEUTRON SOURCE BEAM CURRENT MONITOR ELECTRONICS.  

SciTech Connect

The Spallation Neutron Source (SNS) to be constructed at ORNL is a collaboration of six laboratories. Beam current monitors for SNS will be used to monitor H-minus and H-plus beams ranging from the 15 mA (tune-up in the Front End and Linac) to over 60 A fully accumulated in the Ring. The time structure of the beams to be measured range from 645 nsec ''mini'' bunches, at the 1.05 MHz ring revolution rate, to an overall 1 mS long macro pulse. Beam current monitors (BCMs) for SNS have requirements depending upon their location within the system. The development of a general approach to satisfy requirements of various locations with common components is a major design objective. This paper will describe the development of the beam current monitors and electronics.

KESSELMAN, M.

2001-06-18

126

Shielding Ddsign and analyses of KIPT neutron source facility.  

SciTech Connect

Argonne National Laboratory (ANL) of USA and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on the conceptual design development of a neutron source facility. An electron accelerator drives a sub-critical facility (ADS) is used for generating the neutron source. The facility will be utilized for performing basic and applied nuclear researches, producing medical isotopes, and training young nuclear specialists. Monte Carlo code MCNPX has been utilized as the major design tool for the design, due to its capability to transport electrons, photons, and neutrons at high energies. However the ADS shielding calculations with MCNPX need enormous computational resources and the small neutron yield per electron makes sampling difficulty for the Monte Carlo calculations. The high energy electrons (E > 100 MeV) generate very high energy neutrons and these neutrons dominant the total radiation dose outside the shield. The radiation dose caused by high energy neutrons is {approx}3-4 orders of magnitude higher than that of the photons. However, the high energy neutron fraction within the total generated neutrons is very small, which increases the sampling difficulty and the required computational time. To solve these difficulties, the user subroutines of MCNPX are utilized to generate a neutron source file, which record the generated neutrons from the photonuclear reactions caused by electrons. This neutron source file is utilized many times in the following MCNPX calculations for weight windows (importance function) generation and radiation dose calculations. In addition, the neutron source file can be sampled multiple times to improve the statistics of the calculated results. In this way the expensive electron transport calculations can be performed once with good statistics for the different ADS shielding problems. This paper presents the method of generating and utilizing the neutron source file by MCNPX for the ADS shielding calculation and similar accelerator facilities, and the accurate radiation dose analyses outside the shield using modest computational resources.

Zhong, Z.; Gohar, Y. (Nuclear Engineering Division)

2011-01-01

127

Electronic neutron sources for compensated porosity well logging  

NASA Astrophysics Data System (ADS)

The viability of replacing Americium-Beryllium (Am-Be) radiological neutron sources in compensated porosity nuclear well logging tools with D-T or D-D accelerator-driven neutron sources is explored. The analysis consisted of developing a model for a typical well-logging borehole configuration and computing the helium-3 detector response to varying formation porosities using three different neutron sources (Am-Be, D-D, and D-T). The results indicate that, when normalized to the same source intensity, the use of a D-D neutron source has greater sensitivity for measuring the formation porosity than either an Am-Be or D-T source. The results of the study provide operational requirements that enable compensated porosity well logging with a compact, low power D-D neutron generator, which the current state-of-the-art indicates is technically achievable.

Chen, A. X.; Antolak, A. J.; Leung, K.-N.

2012-08-01

128

First neutron generation in the BINP accelerator based neutron source.  

PubMed

Pilot innovative facility for neutron capture therapy was built at Budker Institute of Nuclear Physics, Novosibirsk. This facility is based on a compact vacuum insulation tandem accelerator designed to produce proton current up to 10 mA. Epithermal neutrons are proposed to be generated by 1.915 MeV protons bombarding a lithium target using (7)Li(p,n)(7)Be threshold reaction. The results of the first experiments on neutron generation are reported and discussed. PMID:19375928

Bayanov, B; Burdakov, A; Chudaev, V; Ivanov, A; Konstantinov, S; Kuznetsov, A; Makarov, A; Malyshkin, G; Mekler, K; Sorokin, I; Sulyaev, Yu; Taskaev, S

2009-07-01

129

Pulsed neutron sources for condensed-matter research  

SciTech Connect

The efforts around the world to provide higher neutron intensities are now focussed on accelerator-driven spallation sources in which neutrons are produced by bombardment of heavy metal targets with high energy protons. Spallation sources can be pulsed or quasi-continuous depending on the nature of the proton accelerator. Pulsed spallation sources, based on rapid cycling synchrotrons or storage rings, are especially attractive since a moderate average proton current (10/sup -5/ - 10/sup -3/A) can produce high instantaneous neutron intensities which can be used with time-of-flight methods to provide powerful neutron spectrometers.

Price, D.L.

1980-01-01

130

Performance of a Clad Tungsten Rod Spallation Neutron Source Target  

Microsoft Academic Search

Tungsten rods, slip-clad with Type 304L stainless steel, performed successfully as a spallation neutron source target operating to a peak fluence of 4 x 10²¹ p\\/cm². The target was used as a neutron source during the Accelerator Production of Tritium (APT) materials irradiation program at the Los Alamos Neutron Science Center. Tungsten rods of 2.642-mm diameter were slip-fit in Type

Walter F. Sommer; Stuart A. Maloy; McIntyre R. Louthan; Gordon J. Willcutt; Phillip D. Ferguson; Michael R. James

2005-01-01

131

Production, distribution and applications of californium-252 neutron sources.  

PubMed

The radioisotope 252Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-yr half-life. A source the size of a person's little finger can emit up to 10(11) neutrons s(-1). Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement and minerals, as well as for detection and identification of explosives, land mines and unexploded military ordinance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 yr of experience and by US Bureau of Mines tests of source survivability during explosions. The production and distribution center for the US Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). DOE sells 252Cf to commercial reencapsulators domestically and internationally. Sealed 252Cf sources are also available for loan to agencies and subcontractors of the US government and to universities for educational, research and medical applications. The REDC has established the Californium User Facility (CUF) for Neutron Science to make its large inventory of 252Cf sources available to researchers for irradiations inside uncontaminated hot cells. Experiments at the CUF include a land mine detection system, neutron damage testing of solid-state detectors, irradiation of human cancer cells for boron neutron capture therapy experiments and irradiation of rice to induce genetic mutations. PMID:11003521

Martin, R C; Knauer, J B; Balo, P A

2000-01-01

132

High-Power Linac for the Spallation Neutron Source  

Microsoft Academic Search

The Spallation Neutron Source (SNS) will be the world's most intense source of neutrons for fundamental science and industrial applications. Design and construction of this facility, located at Oak Ridge, is a joint venture between six DOE laboratories. Construction began in 1999 and is currently ahead of the scheduled 2006 completion date. Injecting a high-power, pulsed proton beam into a

D. J. Rej

2002-01-01

133

A capture-gated neutron spectrometer for characterization of neutron sources and their shields  

NASA Astrophysics Data System (ADS)

A portable capture-gated neutron spectrometer was designed and built. The spectrometer consists of a boron-loaded scintillator. Data acquisition is performed in list-mode. 252Cf and AmBe sources and various neutron and gamma shields were used to characterize the response of the device. It is shown that both the unfolded capture-gated neutron spectrum and the singles spectrum up to 5 MeV should be utilized. Source identification is then possible and important information is revealed regarding the surroundings of the source. The detector's discrimination of neutrons from photons is relatively good; specifically, one out of 105 photons is misclassified as a neutron and, more importantly, this misclassification rate can be calculated precisely for different measurement environments and can be taken into account in setting alarm limits for neutron detection. The source and source shield identification capabilities of the detector make it an interesting asset for security applications.

Holm, Philip; Perjrvi, Kari; Ristkari, Samu; Siiskonen, Teemu; Toivonen, Harri

2014-07-01

134

Neutrino Physics at Pulsed Spallation Neutron Sources  

NASA Astrophysics Data System (ADS)

The 2MW, 1Gev Spallation Neutron Source, under construction at ORNL, is an excellent example of a facility that offers unique opportunities for experiments relevant to particle physics, neutrino astrophysics, nuclear physics, and cosmology. Numerical feasibility studies have been carried out for experimental measurements of neutrino oscillation parameters, ?-nucleus reactions, for example: d(?_e,e^-)pp, ^16O(?_e,e^-) ^16F, ^12C(?_e,e^-) ^12N_gs, ^12C(?,?^`) ^12C, ^56Fe(?_e,e^-) ^56Co, and other reactions using the same techniques. In addition, precision measurements of both charge-current and neutral-current cross sections for electron-neutrino elastic scattering can be done at such facilities when the pulse duration allows the separation of ?_? from ?e and \\overline?_?. The above and other feasible reactions would be very useful in analyzing the data from the SNO and other solar neutrino experiments, in tuning nuclear models used in supernovae computations, and in shedding light on weak interactions in nuclei. A broad selection of neutrino physics topics will be discussed. The physics that will be discussed applies to any intense, pulsed, stopped pion source.

Avignone, Frank T., III

2001-10-01

135

Development of high intensity deuteron ion source for the fusion intense neutron source  

Microsoft Academic Search

A high intensity deuteron ion source has been developed in order to increase the neutron flax from the D-T neutron source for Fusion Neutronics Source at JAERI. It is possible to extract more than 50 mA of deuteron beam at the beam energy of 50 keV. The lifetime of the tungsten filaments utilized in the ion source has been achieved

M. Kinsho; M. Sugimoto; M. Seki; H. Oguri; Y. Okumura

2000-01-01

136

Production, Distribution, and Applications of Californium-252 Neutron Sources  

SciTech Connect

The radioisotope {sup 252}Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6-year half-life. A source the size of a person's little finger can emit up to 10{sup 11} neutrons/s. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement, and minerals, as well as for detection and identification of explosives, laud mines, and unexploded military ordnance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards, and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 years of experience and by U.S. Bureau of Mines tests of source survivability during explosions. The production and distribution center for the U. S Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL). DOE sells The radioisotope {sup 252}Cf is routinely encapsulated into compact, portable, intense neutron sources with a 2.6- year half-life. A source the size of a person's little finger can emit up to 10 neutrons/s. Californium-252 is used commercially as a reliable, cost-effective neutron source for prompt gamma neutron activation analysis (PGNAA) of coal, cement, and minerals, as well as for detection and identification of explosives, laud mines, and unexploded military ordnance. Other uses are neutron radiography, nuclear waste assays, reactor start-up sources, calibration standards, and cancer therapy. The inherent safety of source encapsulations is demonstrated by 30 years of experience and by U.S. Bureau of Mines tests of source survivability during explosions. The production and distribution center for the U. S Department of Energy (DOE) Californium Program is the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory(ORNL). DOE sells {sup 252}Cf to commercial reencapsulators domestically and internationally. Sealed {sup 252}Cf sources are also available for loan to agencies and subcontractors of the U.S. government and to universities for educational, research, and medical applications. The REDC has established the Californium User Facility (CUF) for Neutron Science to make its large inventory of {sup 252}Cf sources available to researchers for irradiations inside uncontaminated hot cells. Experiments at the CUF include a land mine detection system, neutron damage testing of solid-state detectors, irradiation of human cancer cells for boron neutron capture therapy experiments, and irradiation of rice to induce genetic mutations.

Balo, P.A.; Knauer, J.B.; Martin, R.C.

1999-10-03

137

An overview of the planned advanced neutron source facility  

SciTech Connect

The Advanced Neutron Source (ANS), now in the conceptual design stage, will be a new user facility for neutron research, including neutron beam experiments, materials irradiation testing and materials analysis capabilities, and production facilities for transuranic and lighter isotopes. The neutron source is to be the world's highest flux beam reactor and is based on existing reactor technology to minimize safety issues. The preferred fuel, U{sub 3}Si{sub 2}, has been tested in operating reactors in the United States, Japan, and Europe. The core is cooled, moderated, and reflected by heavy water, common practice for research reactors. 3 refs., 9 figs., 3 tabs.

West, C.D.

1990-01-01

138

Superthermal source of ultracold neutrons for fundamental physics experiments.  

PubMed

Ultracold neutrons (UCNs) play an important role for precise measurements of the properties of the neutron and its interactions. During the past 25 years, a neutron turbine coupled to a liquid deuterium cold neutron source at a high-flux reactor has defined the state of the art for UCN production, despite a long history of efforts towards a new generation of UCN sources. This Letter reports a world-best UCN density available for users, achieved with a new source based on conversion of cold neutrons in superfluid helium. A conversion volume of 5 liters provides at least 274,000 UCN in a single accumulation run. Cyclically repeated operation of the source has been demonstrated, as well. PMID:22026860

Zimmer, Oliver; Piegsa, Florian M; Ivanov, Sergey N

2011-09-23

139

Accelerator-based neutron source for the neutron-capture and fast neutron therapy at hospital  

NASA Astrophysics Data System (ADS)

The proton accelerator complex for neutron production in lithium target discussed, which can operate in two modes. The first provides a neutron beam kinematically collimated with good forward direction in 25 and average energy of 30 keV, directly applicable for neutron-capture therapy with high efficiency of proton beam use. The proton energy in this mode is 1.883-1.890 MeV that is near the threshold of the 7Li( p, n) 7Be reaction. In the second mode, at proton energy of 2.5 MeV, the complex-produced neutron beam with maximum energy board of 790 keV which can be used directly for fast neutron therapy and for neutron-capture therapy after moderation. The project of such a neutron source is based on the 2.5 MeV original electrostatic accelerator tandem with vacuum insulation developed at BINP which is supplied with a high-voltage rectifier. The rectifier is produced in BINP as a part of ELV-type industrial accelerator. Design features of the tandem determining its high reliability in operation with a high-current (up to 40 mA) H - ion beam are discussed. They are: the absence of ceramic accelerator columns around the beam passage region, good conditions for pumping out of charge-exchange gaseous target region, strong focusing optics and high acceleration rate minimizing the space charge effects. The possibility of stabilization of protons energy with an accuracy level of 0.1% necessary for operation in the near threshold region is considered. The design description of H - continuous ion source with a current of 40 mA is also performed. To operate with a 100 kW proton beam it is proposed to use liquid-lithium targets. A thin lithium layer on the surface of a tungsten disk cooled intensively by a liquid metal heat carrier is proposed for use in case of the vertical beam, and a flat liquid lithium jet flowing through the narrow nozzle - for the horizontal beam.

Bayanov, B. F.; Belov, V. P.; Bender, E. D.; Bokhovko, M. V.; Dimov, G. I.; Kononov, V. N.; Kononov, O. E.; Kuksanov, N. K.; Palchikov, V. E.; Pivovarov, V. A.; Salimov, R. A.; Silvestrov, G. I.; Skrinsky, A. N.; Soloviov, N. A.; Taskaev, S. Yu.

140

Advanced Neutron Source (ANS) Project Progress report, FY 1991  

SciTech Connect

This report discusses the following about the Advanced Neutron Source: Project Management; Research and Development; Fuel Development; Corrosion Loop Tests and Analyses; Thermal-Hydraulic Loop Tests; Reactor Control and Shutdown Concepts; Critical and Subcritical Experiments; Material Data, Structural Tests, and Analysis; Cold-Source Development; Beam Tube, Guide, and Instrument Development; Hot-Source Development; Neutron Transport and Shielding; I & C Research and Development; Design; and Safety.

Campbell, J.H. [ed.] [Oak Ridge National Lab., TN (United States); Selby, D.L.; Harrington, R.M. [Oak Ridge National Lab., TN (United States); Thompson, P.B. [Martin Marietta Energy Systems, Inc., (United States). Engineering Division

1992-01-01

141

Advanced Neutron Source (ANS) Project Progress report, FY 1991  

SciTech Connect

This report discusses the following about the Advanced Neutron Source: Project Management; Research and Development; Fuel Development; Corrosion Loop Tests and Analyses; Thermal-Hydraulic Loop Tests; Reactor Control and Shutdown Concepts; Critical and Subcritical Experiments; Material Data, Structural Tests, and Analysis; Cold-Source Development; Beam Tube, Guide, and Instrument Development; Hot-Source Development; Neutron Transport and Shielding; I C Research and Development; Design; and Safety.

Campbell, J.H. (ed.) (Oak Ridge National Lab., TN (United States)); Selby, D.L.; Harrington, R.M. (Oak Ridge National Lab., TN (United States)); Thompson, P.B. (Martin Marietta Energy Systems, Inc., (United States). Engineering Division)

1992-01-01

142

Pulsed neutron source cold moderators --- concepts, design and engineering  

SciTech Connect

Moderator design for pulsed neutron sources is becoming more and more an interface area between source designers and instrument designers. Although there exists a high degree of flexibility, there are also physical and technical limitations. This paper aims at pointing out these limitations and examining ways to extend the current state of moderator technology in order to make the next generation neutron sources even more versatile and flexible tools for science in accordance with the users' requirements. (auth)

Bauer, Guenter S.

1997-01-01

143

PLUTONIUM-BERYLLIUM NEUTRON SOURCES THEIR FABRICATION AND THEIR YIELD  

Microsoft Academic Search

An investigntion of the plutonium-beryllium phase diagram demonstrates ;\\u000a the suitability of these alloys and most particularly the intermetallic compound ;\\u000a PuBe for stable neutron sources. These sources are superior to polonium-;\\u000a beryllium sources in respect to sthbility of neutron yield as a iunction of time ;\\u000a and the prediotability of neutroc yield as a function of mass. The gamma-ray

R. E. Tate; A. S. Coffinberry

1958-01-01

144

Basic physics with spallation-neutron sources  

Microsoft Academic Search

The neutron has unique intrinsic properties widely used in basic and applied sciences. The neutron plays a well-known role in applied sciences and technology and is a unique probe well suited for the exploration of condensed-matter properties. But the neutron is also used for many other basic-physics studies, including nuclear physics, particle physics, fundamental physics, astrophysics, and cosmology. These last

Michaudon

1994-01-01

145

A Dipole Assisted IEC Neutron Source  

SciTech Connect

A potential opportunity to enhance Inertial Electrostatic Confinement (IEC) fusion exists by augmenting it with a magnetic dipole configuration. The theory is that the dipole fields will enhance the plasma density in the center region of the IEC and the combined IEC and dipole confinement properties will reduce plasma losses. To demonstrate that a hybrid Dipole-IEC configuration can provide an improved neutron source vs. a stand alone IEC, a first model Dipole-IEC experiment was benchmarked against a reference IEC. A triple Langmuir probe was used to find the electron temperature and density. It was found that the magnetic field increases the electron density by a factor of 16, the electron temperature decreases in the presence of a magnetic field, the discharge voltage decreases in the presence of a magnetic field, the potential of the dipole strongly influences the densities obtained in the center. The experimental set-up and plasma diagnostics are discussed in detail, as well as the results, and the developmental issues.

Prajakti Joshi Shrestha

2005-11-28

146

BINP accelerator based epithermal neutron source.  

PubMed

Innovative facility for neutron capture therapy has been built at BINP. This facility is based on compact vacuum insulation tandem accelerator designed to produce proton current up to 10 mA. Epithermal neutrons are proposed to be generated by 1.915-2.5 MeV protons bombarding a lithium target using (7)Li(p,n)(7)Be threshold reaction. In the article, diagnostic techniques for proton beam and neutrons developed are described, results of experiments on proton beam transport and neutron generation are shown, discussed, and plans are presented. PMID:21439836

Aleynik, V; Burdakov, A; Davydenko, V; Ivanov, A; Kanygin, V; Kuznetsov, A; Makarov, A; Sorokin, I; Taskaev, S

2011-12-01

147

A clean, bright, and versatile source of neutron decay products  

E-print Network

We present a case study on a new type of cold neutron beam station for the investigation of angular correlations in the beta-decay of free neutrons. With this beam station, called PERC, the 'active decay volume' lies inside the neutron guide, and the charged neutron decay products are magnetically guided towards the end of the neutron guide. Hence, the guide delivers at its exit a beam of decay electrons and protons, under well-defined and precisely variable conditions, which can be well separated from the cold neutron beam. In this way a general-purpose source of neutron decay products is obtained which can be used for various different experiments in neutron decay correlation spectroscopy. A gain in phase space density of several orders of magnitude can be achieved with PERC, as compared to existing neutron decay spectrometers. Neutron beam related background is separately measurable in PERC, and magnetic mirror effects on the charged neutron decay products and edge effects in the active neutron beam volume...

Dubbers, D; Baessler, S; Maerkisch, B; Schumann, M; Soldner, T; Zimmer, O

2007-01-01

148

A clean, bright, and versatile source of neutron decay products  

E-print Network

We present a case study on a new type of cold neutron beam station for the investigation of angular correlations in the beta-decay of free neutrons. With this beam station, called PERC, the 'active decay volume' lies inside the neutron guide, and the charged neutron decay products are magnetically guided towards the end of the neutron guide. Hence, the guide delivers at its exit a beam of decay electrons and protons, under well-defined and precisely variable conditions, which can be well separated from the cold neutron beam. In this way a general-purpose source of neutron decay products is obtained which can be used for various different experiments in neutron decay correlation spectroscopy. A gain in phase space density of several orders of magnitude can be achieved with PERC, as compared to existing neutron decay spectrometers. Neutron beam related background is separately measurable in PERC, and magnetic mirror effects on the charged neutron decay products and edge effects in the active neutron beam volume are both strongly suppressed. Therefore the spectra and angular distributions of the emerging decay particles will be distortion-free on the level of 10^-4, more than 10 times better than achieved today.

D. Dubbers; H. Abele; S. Baessler; B. Maerkisch; M. Schumann; T. Soldner; O. Zimmer

2007-09-27

149

Microtron MT 25 as a source of neutrons  

SciTech Connect

The objective was to describe Microtron MT25 as a source of neutrons generated by bremsstrahlung induced photonuclear reactions in U and Pb targets. Bremsstrahlung photons were produced by electrons accelerated at energy 21.6 MeV. Spectral fluence of the generated neutrons was calculated with MCNPX code and then experimentally determined at two positions by means of a Bonner spheres spectrometer in which the detector of thermal neutrons was replaced by activation Mn tablets or track detectors CR-39 with a {sup 10}B radiator. The measured neutron spectral fluence and the calculated anisotropy served for the estimation of neutron yield from the targets and for the determination of ambient dose equivalent rate at the place of measurement. Microtron MT25 is intended as one of the sources for testing neutron sensitive devices which will be sent into the space.

Kralik, M.; Solc, J. [Czech Metrology Institute, CZ-102 00 Prague 10 (Czech Republic); Chvatil, D.; Krist, P.; Turek, K. [Nuclear Physics Institute, p.r.i., AS CR, CZ-250 68 Rez (Czech Republic); Granja, C. [Institute of Experimental and Applied Physics, Horska 3a/22, CZ-128 00 Prague 2 (Czech Republic)

2012-08-15

150

Transmission Bragg edge spectroscopy measurements at ORNL Spallation Neutron Source  

NASA Astrophysics Data System (ADS)

Results of neutron transmission Bragg edge spectroscopic experiments performed at the SNAP beamline of the Spallation Neutron Source are presented. A high resolution neutron counting detector with a neutron sensitive microchannel plate and Timepix ASIC readout is capable of energy resolved two dimensional mapping of neutron transmission with spatial accuracy of ~55 ?m, limited by the readout pixel size, and energy resolution limited by the duration of the initial neutron pulse. A two dimensional map of the Fe 110 Bragg edge position was obtained for a bent steel screw sample. Although the neutron pulse duration corresponded to ~30 m energy resolution for 15.3 m flight path, the accuracy of the Bragg edge position in our measurements was improved by analytical fitting to a few m level. A two dimensional strain map was calculated from measured Bragg edge values with an accuracy of ~few hundreds ?istrain for 300s of data acquisition time.

Tremsin, A. S.; McPhate, J. B.; Vallerga, J. V.; Siegmund, O. H. W.; Feller, W. B.; Bilheux, H. Z.; Molaison, J. J.; Tulk, C. A.; Crow, L.; Cooper, R. G.; Penumadu, D.

2010-11-01

151

Physical design of target station and neutron instruments for China Spallation Neutron Source  

NASA Astrophysics Data System (ADS)

The China Spallation Neutron Source (CSNS) is the first accelerator-based multidiscipline user facility to produce pulsed neutrons by tungsten target under collision of a pulsed proton beam with a beam power of 100 kW at a repetition rate of 25 Hz. In this paper, we focus on the physical design of CSNS target station and neutron instruments. Under optimized design, the flat tungsten target and the compact target-moderator-reflector coupling enhance effective cold and thermal neutron output from moderators. Three wing-type moderators supply four different characteristics of neutrons to 19 beamlines primarily for neutron scattering applications. Layout of neutron instruments are conceptually planned for total 20 beamlines, the configuration and specification have been determined for three day-one neutron instruments. All designs are optimized for the Phase I of 100 kW with a upgradable capacity to 500 kW.

Wang, FangWei; Liang, TianJiao; Yin, Wen; Yu, QuanZhi; He, LunHua; Tao, JuZhou; Zhu, Tao; Jia, XueJun; Zhang, ShaoYing

2013-12-01

152

Neutron sources for test and calibration of neutron detectors for space research  

NASA Astrophysics Data System (ADS)

This work reports on the current status of neutron sources in the Czech Republic as calibrated and ESA compliant stations for space related applications such as the testing and calibration of neutron detectors and neutron sensitive devices as well as for studies of radiation effects of electric and electronic components. The work was carried out as part of the preparatory accession activities of the Czech Republic with ESA. The goal and one of the tasks is to test and evaluate neutron sensitive devices, both conventional and prototypes, developed at ESA and at the IEAP CTU Prague. The facilities consist of both fast and thermal neutron sources providing testing and absolute calibration of a wide range of neutron detectors. The evaluation and calibration of the sources were carried out in cooperation with the Nuclear Physics Institute, Academy of Sciences of the Czech Republic, the Research Center Rez, and the Czech Metrology Institute in Prague.

Granja, C.; Kralik, M.; Kohout, Z.; Masek, P.; Pospisil, S.; Solar, M.; Solc, J.; Vykydal, Z.; Owens, A.; Vacik, J.; Chvatil, D.; Bem, P.; Krist, P.; Stursa, J.; Rypar, V.

2012-02-01

153

LABORATORY EXPERIMENTS USING A PULSED NEUTRON SOURCE  

Microsoft Academic Search

Laboratory experiments using pulsed neutron techniques are valuable for ; giving physical interpretation of reactor theory. Three experiments illustrate ; different pulsed neutron measurements. In one case diffusion properties of a ; sample are measured by varying the geometry of the sample. In another the ; absorption cross section of a solute is measured by varying the sample without ;

R. B. Mesler; H. G. OBrien; D. Freed

1962-01-01

154

Inertial electrostatic confinement I(IEC) neutron sources  

SciTech Connect

Inertial Electrostatic Confinement (IEC) is one of the earliest plasma confinement concepts, having first been suggested by P.T. Farnsworth in the 1950s. The concept involves a simple apparatus of concentric spherical electrostatic grids or a combination of grids and magnetic fields. An electrostatic structure is formed from the confluence of electron or ion beams. Gridded IEC systems have demonstrated neutron yields as high as 2*10 [10]. neutrons/sec in steady state. These systems have considerable potential as small, inexpensive, portable neutron sources for assaying applications. Neutron tomography is also a potential application. This paper discusses the IEC concept and how it can be adapted to a steady-state assaying source and an intense pulsed neutron source. Theoretical modeling and experimental results are presented.

Nebel, R.A.; Barnes, D.C.; Caramana, E.J.; Janssen, R.D.; Nystrom, W.D.; Tiouririne, T.N.; Trent, B.C. [Los Alamos National Lab., NM (United States); Miley, G.H.; Javedani, J. [Illinois Univ., Urbana, IL (United States)

1995-12-01

155

The National Spallation Neutron Source Collaboration: Towards a new pulsed neutron source in the United States  

SciTech Connect

The US Department of Energy has commissioned Oak Ridge National Laboratory to initiate the conceptual design for a next-generation pulsed spallation neutron source. Current expectation is for a construction start in FY 1998, with commencement of operations in 2004. For this project, ORNL has entered into a collaborative arrangement with LBNL, BNL, LANL (and most recently ANL). The conceptual design study is now well underway, building on the strong base of the extensive work already performed by various Laboratories, as well as input from the user community (from special BESAC subpanels). Study progress, including accelerator configuration and plans for resolution of critical issues, is reported in this paper.

Appleton, B.R.; Ball, J.B.; Alonso, J.R. [Oak Ridge National Lab., TN (United States); Gough, R.A. [Lawrence Berkeley National Lab., CA (United States); Weng, W.T. [Brookhaven National Lab., Upton, NY (United States); Jason, A. [Los Alamos National Lab., NM (United States); The National Spallation Neutron Source Collaboration

1996-07-01

156

Monte-Carlo simulations of elastically backscattered neutrons from hidden explosives using three different neutron sources.  

PubMed

Calculations of elastically backscattered (EBS) neutrons from hidden explosives buried in soil were performed using Monte-Carlo N-particle transport code MCNP5. Three different neutron sources were used in the study. The study re-examines the performance of the neutron backscattering methods in providing identification of hidden explosives through their chemical composition. The EBS neutron energy spectra of fast and slow neutrons of the major constituent elements in soil and an explosive material in form of TNT have shown definite structures that can be used for the identification of a buried landmine. PMID:18823788

Elagib, I; Elsheikh, N; Alsewaidan, H; Habbani, F

2009-01-01

157

Facility for fast neutron irradiation tests of electronics at the ISIS spallation neutron source  

SciTech Connect

The VESUVIO beam line at the ISIS spallation neutron source was set up for neutron irradiation tests in the neutron energy range above 10 MeV. The neutron flux and energy spectrum were shown, in benchmark activation measurements, to provide a neutron spectrum similar to the ambient one at sea level, but with an enhancement in intensity of a factor of 10{sup 7}. Such conditions are suitable for accelerated testing of electronic components, as was demonstrated here by measurements of soft error rates in recent technology field programable gate arrays.

Andreani, C.; Pietropaolo, A.; Salsano, A. [Centro NAST, Universita degli Studi di Roma Tor Vergata (Italy); Gorini, G.; Tardocchi, M. [Dipartimento di Fisica 'G. Occhialini', Universita degli Studi di Milano-Bicocca (Italy); Paccagnella, A.; Gerardin, S. [Dipartimento di Ingegneria dell'Informazione, Universita di Padova (Italy); Frost, C. D.; Ansell, S. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom); Platt, S. P. [School of Computing, Engineering and Physical Sciences, University of Central Lancashire, Preston, Lancs. PR1 2HE (United Kingdom)

2008-03-17

158

Summary of alpha-neutron sources in GADRAS.  

SciTech Connect

A common source of neutrons for calibration and testing is alpha-neutron material, named for the alpha-neutron nuclear reaction that occurs within. This material contains a long-lived alpha-emitter and a lighter target element. When the alpha particle from the emitter is absorbed by the target, neutrons and gamma rays are released. Gamma Detector Response and Analysis Software (GADRAS) includes built-in alpha-neutron source definitions for AcC, AmB, AmBe, AmF, AmLi, CmC, and PuC. In addition, GADRAS users may create their own alpha-neutron sources by placing valid alpha-emitters and target elements in materials within their one-dimensional models (1DModel). GADRAS has the ability to use pre-built alpha-neutron sources for plotting or as trace-sources in 1D models. In addition, if any material (existing or user-defined) specified in a 1D model contains both an alpha emitter in conjunction with a target nuclide, or there is an interface between such materials, then the appropriate neutron-emission rate from the alpha-neutron reaction will be computed. The gamma-emissions from these sources are also computed, but are limited to a subset of nine target nuclides. If a user has experimental data to contribute to the alpha-neutron gamma emission database, it may be added directly or submitted to the GADRAS developers for inclusion. The gadras.exe.config file will be replaced when GADRAS updates are installed, so sending the information to the GADRAS developers is the preferred method for updating the database. This is also preferable because it enables other users to benefit from your efforts.

Mitchell, Dean James; Thoreson, Gregory G.; Harding, Lee T.

2012-05-01

159

Tagging fast neutrons from an (241)Am/(9)Be source.  

PubMed

Shielding, coincidence, and time-of-flight measurement techniques are employed to tag fast neutrons emitted from an (241)Am/(9)Be source resulting in a continuous polychromatic energy-tagged beam of neutrons with energies up to 7MeV. The measured energy structure of the beam agrees qualitatively with both previous measurements and theoretical calculations. PMID:25644080

Scherzinger, J; Annand, J R M; Davatz, G; Fissum, K G; Gendotti, U; Hall-Wilton, R; Hkansson, E; Jebali, R; Kanaki, K; Lundin, M; Nilsson, B; Rosborge, A; Svensson, H

2015-04-01

160

Some experiments on ultrasonic cavitation using a pulsed neutron source  

Microsoft Academic Search

Experiments on the prompt neutron-induced cavitation effect in tetrachloroethylene are described. Cavitation bubbles were detected by the fast acoustic signals they emit, probably during the collapse phase. Using a pulsed fast-neutron source phase locked to the acoustic field, and a time analyser, information was obtained on the history of bubbles which were nucleated at a known phase of the sound

R. Howlett

1968-01-01

161

Residual stress measurement using the pulsed neutron source at LANSCE  

Microsoft Academic Search

The presence of residual stress in engineering components can effect their mechanical properties and structural integrity. Neutron diffraction is the only measuring technique which can make spatially resolved non-destructive strain measurements in the interior of components. By recording the change in the crystalline interplanar spacing, elastic strains can be measured for individual lattice reflections. Using a pulsed neutron source, all

M. A. M. Bourke; J. A. Goldstone; T. M. Holden

1991-01-01

162

Materials compatibility studies for the Spallation Neutron Source  

Microsoft Academic Search

The Spallation Neutron Source (SNS) is a high power facility for producing neutrons that utilizes flowing liquid mercury inside an austenitic stainless steel container as the target for a 1.0 GeV proton beam. Type 316 SS has been selected as the container material for the mercury and consequences of exposure of 316 SS to radiation, thermal shock, thermal stress, cavitation

J. R. DiStefano; S. J. Pawel; E. T. Manneschmidt

1998-01-01

163

An ultra-cold neutron source at the MLNSC  

SciTech Connect

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors have carried out the research and development of an Ultra-Cold Neutron (UCN) source at the Manuel Lujan Neutron Scattering Center (MLNSC). A first generation source was constructed to test the feasibility of a rotor source. The source performed well with an UCN production rate reasonably consistent with that expected. This source can now provide the basis for further development work directed at using UCN in fundamental physics research as well as possible applications in materials science.

Bowles, T.J.; Brun, T.; Hill, R.; Morris, C.; Seestrom, S.J. [Los Alamos National Lab., NM (United States); Crow, L. [Univ. of Rhode Island, Kingston, RI (United States); Serebrov, A. [Petersburg Nuclear Physics Inst. (Russian Federation)

1998-11-01

164

Phase contrast neutron imaging at a medium intensity neutron source  

Microsoft Academic Search

Neutron Imaging is a technique for the nondestructive testing (NDT) of materials. It is characterized by its sensitivity to materials composed of low atomic number (Z) elements such as hydrogen. Enhancement of the spatial resolution and the contrast of the obtained images are primary objectives that are continuously being pursued in the development of this technique. An approach of improving

Kaushal K. Mishra; Ayman I. Hawari

2009-01-01

165

Advanced Neutron Source radiological design criteria  

SciTech Connect

The operation of the proposed Advanced Neutron Source (ANS) facility will present a variety of radiological protection problems. Because it is desired to design and operate the ANS according to the applicable licensing standards of the Nuclear Regulatory Commission (NRC), it must be demonstrated that the ANS radiological design basis is consistent not only with state and Department of Energy (DOE) and other usual federal regulations, but also, so far as is practicable, with NRC regulations and with recommendations of such organizations as the Institute of Nuclear Power Operations (INPO) and the Electric Power Research Institute (EPRI). Also, the ANS radiological design basis is in general to be consistent with the recommendations of authoritative professional and scientific organizations, specifically the National Council on Radiation Protection and Measurements (NCRP) and the International Commission on Radiological Protection (ICRP). As regards radiological protection, the principal goals of DOE regulations and guidance are to keep occupational doses ALARA [as low as (is) reasonably achievable], given the current state of technology, costs, and operations requirements; to control and monitor contained and released radioactivity during normal operation to keep public doses and releases to the environment ALARA; and to limit doses to workers and the public during accident conditions. Meeting these general design objectives requires that principles of dose reduction and of radioactivity control by employed in the design, operation, modification, and decommissioning of the ANS. The purpose of this document is to provide basic radiological criteria for incorporating these principles into the design of the ANS. Operations, modification, and decommissioning will be covered only as they are affected by design.

Westbrook, J.L.

1995-08-01

166

Compact, energy EFFICIENT neutron source: enabling technology for various applications  

SciTech Connect

A novel neutron source comprising of a deuterium beam (energy of about 100 KeV) injected into a tube filled with tritium gas and/or tritium plasma that generates D-T fusion reactions, whose products are 14.06 MeV neutrons and 3.52 MeV alpha particles, is described. At the opposite end of the tube, the energy of deuterium ions that did not interact is recovered. Beryllium walls of proper thickness can be utilized to absorb 14 MeV neutrons and release 2-3 low energy neutrons. Each ion source and tube forms a module. Larger systems can be formed from multiple units. Unlike currently proposed methods, where accelerator-based neutron sources are very expensive, large, and require large amounts of power for operation, this neutron source is compact, inexpensive, easy to test and to scale up. Among possible applications for this neutron source concept are sub-critical nuclear breeder reactors and transmutation of radioactive waste.

Hershcovitch, A.; Roser, T.

2009-12-01

167

Non-destructive actinide assay of neutron sources  

NASA Astrophysics Data System (ADS)

Transuranic neutron sources were assayed using ?-spectrometry and neutron counting, with respect to revealing illicit trafficking of radioactive and nuclear materials. Source type and constituents were identified by ?-spectrometry. For determining the source strength of 244Cm, 252Cf, AmBe, AmLi and 238PuBe sources, a passive neutron coincidence collar was used with 3He counters in two moderator configurations. The electronics consist of independent channels of pulse amplifiers and discriminators as well as a shift register for coincidence counting. From the neutron output of the sources measured by gross neutron counting, the actinide content (or activity) can be assessed by adopting specific spontaneous fission and (?, n) reaction yields of individual isotopes from the literature. Various types of the sources can be characterized by the ratio of the real coincidence counts to total (singles) counts, R/ T. This quantity is a specific constant for different types of spontaneously fissioning sources, not depending on their strength, while exhibits a power function increasing with the strength of (?, n) sources. An individual source of the latter type can additionally be characterized by the ratio of R/ T to the product of detection efficiency and a factor taking into account coincidence loss, irrespective of the instrumental details (detector type and size, moderator thickness, etc.).

Lakosi, Lszl; Nguyen, Cong Tam; Bagi, Jnos

2006-06-01

168

Satellite pulsed tiny neutron source at Kyoto University, Sakyo  

NASA Astrophysics Data System (ADS)

A pulsed neutron source facility will be constructed at Kyoto University, where the accelerated 3.5 MeV proton beam will bombard a Li or Be target to generate neutrons. The average current, the pulse width and the typical repetition rate are 100 ?A, 100 ?s and 70 Hz, respectively. The purposes of the system are neutron imaging, material science, fundamental physics, etc. This kind of compact facility, which can be distributed at modest cost, will help to incubate new ideas and promote growth of neutron science worldwide.

Iwashita, Y.; Nagae, T.; Tanimori, T.; Fujioka, H.; Shimizu, H. M.

2011-04-01

169

Spallation neutron source target station design, development, and commissioning  

NASA Astrophysics Data System (ADS)

The spallation neutron source target station is designed to safely, reliably, and efficiently convert a 1 GeV beam of protons to a high flux of about 1 meV neutrons that are available at 24 neutron scattering instrument beam lines. Research and development findings, design requirements, design description, initial checkout testing, and results from early operation with beam are discussed for each of the primary target subsystems, including the mercury target, neutron moderators and reflector, surrounding vessels and shielding, utilities, remote handling equipment, and instrumentation and controls. Future plans for the mercury target development program are also briefly discussed.

Haines, J. R.; McManamy, T. J.; Gabriel, T. A.; Battle, R. E.; Chipley, K. K.; Crabtree, J. A.; Jacobs, L. L.; Lousteau, D. C.; Rennich, M. J.; Riemer, B. W.

2014-11-01

170

High-power LINAC for the spallation neutron source  

Microsoft Academic Search

The Spallation Neutron Source is a $1.4B project for the U.S. Dept. of Energy to develop the world's most intense source of neutrons for fundamental science and industrial applications. Design and construction of this facility, located at Oak Ridge, is a joint venture between six DOE laboratories. Construction began in 1999 and is currently ahead of the scheduled 2006 completion

D. J. Rej

2001-01-01

171

Calculated neutron dose rates for implantable californium-252 sources  

Microsoft Academic Search

Fast neutron absorbed dose rates near 252Cf finite line sources in several infinite tissue compositions have been calculated. The neutron flux produced by a point source was calculated using the one-dimensional energy-dependent discrete ordinates computer code, DTF-IV. The calculations utilized an S-16 angular quadrature approximation, 21 energy groups and anisotropic scattering up to the third order in the cosine of

J P Windham; A Shapiro; J G Kereiakes

1972-01-01

172

Overview of target systems for the Spallation Neutron Source  

SciTech Connect

The purpose and requirements of target systems as well as the technologies that are being utilized to design and build a state-of-the-art neutron spallation source, the Spallation Neutron Source (SNS), are discussed. Emphasis is given to the technology issues that present the greatest scientific challenges. The present facility configuration, ongoing analysis, and the planned hardware research and development program are also described.

Gabriel, Tony A.; Barnes, John M.; Charlton, Lowell A. [and others; DiStefano, James; Farrell, Ken; Haines, John; Johnson, Jeffrey O.; Mansur, Louis K.; Pawel, Steve J.; Siman-Tov, Moshe; Taleyarkhan, Rusi; Wendel, Mark W.; McManamy, Thomas J.; Rennich, Mark J.

1997-01-01

173

Radionuclide neutron sources in calibration laboratory--neutron and gamma doses and their changes in time.  

PubMed

The calibration laboratory, having standard neutron fields of radionuclide sources, should perform regular measurements of fields' parameters in order to check their stability and to get knowledge of any changes. Usually, accompanying gamma radiation is not of serious concern, but some personal dosemeters, old neutron dose equivalent meters with scintillation detectors and the dose meters of mixed radiation require the determination of this component. In the Laboratory of Radiation Protection Measurements in the Institute of Atomic Energy, Poland, the fields of radionuclide neutron sources (252)Cf, (241)Am-Be and (239)Pu-Be were examined for nearly 20 y. A number of detectors and methods have been applied for the determination of neutron ambient dose equivalent rate and for the determination of neutron and gamma dose components. This paper presents the recent results of measurements of gamma and neutron dose and dose equivalent, compared with the results accumulated in nearly 20 y. PMID:17513855

Jzefowicz, K; Golnik, N; Tulik, P; Zielczynski, M

2007-01-01

174

Extraction of serum vitamin B12 for radio-isotopic and Lactobacillus leichmannii assay.  

PubMed

The protein precipitates discarded during the extraction process of the Lactobacillus leichmannii vitamin B12 assay have been shown to contain significant amounts of vitamin B12. This loss of vitamin B12 provide a satisfactory explanation for many of the descrepancies between the serum vitamin B12 values obtained by the L. leichmannii method and the radio-isotopic method of Raven et al (1969). It is possible to produce lower results by the method of Raven et al (1969)by incorporating into that method the L. leichmannii extraction process; it is also possible to produce higher results by the L. leichmannii method using a papain extraction process. PMID:1150894

Raven, J L; Robson, M B

1975-07-01

175

Brazilian gamma-neutron dosemeter: response to 241AmBe and 252Cf neutron sources.  

PubMed

With the aim of improving the monitoring of workers potentially exposed to neutron radiation in Brazil, the IPEN/CNEN-SP in association with PRO-RAD designed and developed a passive individual gamma-neutron mixed-field dosemeter calibrated to be used to (241)AmBe sources. To verify the dosimetry system response to different neutron spectra, prototypes were irradiated with a (252)Cf source and evaluated using the dose-calculation algorithm developed for (241)AmBe sources. PMID:21186217

Souto, E B; Campos, L L

2011-03-01

176

Fundamental Neutron Physics Beamline at the Spallation Neutron Source at ORNL  

E-print Network

We describe the Fundamental Neutron Physics Beamline (FnPB) facility located at the Spallation Neutron Source at Oak Ridge National Laboratory. The FnPB was designed for the conduct of experiments that investigate scientific issues in nuclear physics, particle physics, astrophysics and cosmology using a pulsed slow neutron beam. We present a detailed description of the design philosophy, beamline components, and measured fluxes of the polychromatic and monochromatic beams.

N. Fomin; G. L. Greene; R. Allen; V. Cianciolo; C. Crawford; T. Ito; P. R. Huffman; E. B. Iverson; R. Mahurin; W. M. Snow

2014-08-04

177

Application of a triga research reactor as the neutron source for a production neutron radiography facility  

Microsoft Academic Search

GA Technologies Inc. (GA) has developed a Stationary Neutron Radiography System (SNRS) using a 250-1000 kW TRIGA reactor as the neutron source. The partially below ground reactor will be equipped with four vertical beam tubes originating in the reactor graphite reflector and installed tangential to the core to provide a strong current of thermal neutrons with minimum gamma-ray contamination. The

Chesworth

1988-01-01

178

Fundamental neutron physics beamline at the spallation neutron source at ORNL  

NASA Astrophysics Data System (ADS)

We describe the Fundamental Neutron Physics Beamline (FnPB) facility located at the Spallation Neutron Source at Oak Ridge National Laboratory. The FnPB was designed for the conduct of experiments that investigate scientific issues in nuclear physics, particle physics, astrophysics and cosmology using a pulsed slow neutron beam. We present a detailed description of the design philosophy, beamline components, and measured fluxes of the polychromatic and monochromatic beams.

Fomin, N.; Greene, G. L.; Allen, R. R.; Cianciolo, V.; Crawford, C.; Tito, T. M.; Huffman, P. R.; Iverson, E. B.; Mahurin, R.; Snow, W. M.

2015-02-01

179

Triple GEM gas detectors as real time fast neutron beam monitors for spallation neutron sources  

NASA Astrophysics Data System (ADS)

A fast neutron beam monitor based on a triple Gas Electron Multiplier (GEM) detector was developed and tested for the ISIS spallation neutron source in U.K. The test on beam was performed at the VESUVIO beam line operating at ISIS. The 2D fast neutron beam footprint was recorded in real time with a spatial resolution of a few millimeters thanks to the patterned detector readout.

Murtas, F.; Croci, G.; Pietropaolo, A.; Claps, G.; Frost, C. D.; Perelli Cippo, E.; Raspino, D.; Rebai, M.; Rhodes, N. J.; Schooneveld, E. M.; Tardocchi, M.; Gorini, G.

2012-07-01

180

Design and Demonstration of a Quasi-monoenergetic Neutron Source  

SciTech Connect

The design of a neutron source capable of producing 24 and 70 keV neutron beams with narrow energy spread is presented. The source exploits near-threshold kinematics of the 7Li(p,n)7Be reaction while taking advantage of the interference `notches' found in the scattering cross-sections of iron. The design was implemented and characterized at the Center for Accelerator Mass Spectrometry at Lawrence Livermore National Laboratory. Alternative lters such as vanadium and manganese are also explored and the possibility of studying the response of di*erent materials to low-energy nuclear recoils using the resultant neutron beams is discussed.

Joshi, T.; Sangiorgio, Samuele; Mozin, Vladimir V.; Norman, E. B.; Sorensen, Peter F.; Foxe, Michael P.; Bench, G.; Bernstein, A.

2014-03-05

181

Design and demonstration of a quasi-monoenergetic neutron source  

E-print Network

The design of a neutron source capable of producing 24 and 70 keV neutron beams with narrow energy spread is presented. The source exploits near-threshold kinematics of the $^{7}$Li(p,n)$^{7}$Be reaction while taking advantage of the interference `notches' found in the scattering cross-sections of iron. The design was implemented and characterized at the Center for Accelerator Mass Spectrometry at Lawrence Livermore National Laboratory. Alternative filters such as vanadium and manganese are also explored and the possibility of studying the response of different materials to low-energy nuclear recoils using the resultant neutron beams is discussed.

T. H. Joshi; S. Sangiorgio; V. Mozin; E. B. Norman; P. Sorensen; M. Foxe; G. Bench; A. Bernstein

2014-05-13

182

New spallation neutron sources, their performance and applications  

SciTech Connect

Pulsed spallation sources now operating in the world are at the KEK Laboratory in Japan (the KENS source), at Los Alamos National Laboratory (WNR) and at Argonne National Laboratory (IPNS), both the latter being in the US. The Intense Pulsed Neutron Source (IPNS) is currently the world's most intense source with a peak neutron flux of 4 x 10/sup 14/ n cm/sup -2/s/sup -1/ at a repetition rate of 30 Hz, and globally producing approx. 1.5 x 10/sup 15/ n/sec. Present pulsed sources are still relatively weak compared to their potential. In 1985 the Rutherford Spallation Neutron Source will come on line, and eventually be approx. 30 more intense than the present IPNS. Later, in 1986 the WNR/PSR option at Los Alamos will make that facility of comparable intensity, while a subcritical fission booster at IPNS will keep IPNS competitive. These new sources will expand the applications of pulsed neutrons but are still based on accelerators built for other scientific purposes, usually nuclear or high-energy physics. Accelerator physicists are now designing machines expressly for spallation neutron research, and the proton currents attainable appear in the milliamps. (IPNS now runs at 0.5 GeV and 14 ..mu..A). Such design teams are at the KFA Laboratory Julich, Argonne National Laboratory and KEK. Characteristics, particularly the different time structure of the pulses, of these new sources will be discussed. S

Not Available

1985-01-01

183

A compact ion source for intense neutron generation  

NASA Astrophysics Data System (ADS)

Today, numerous applications for neutrons, beyond those of the nuclear power industry, are beginning to emerge and become viable. From neutron radiography which, not unlike conventional X-rays, can provide an in-depth image through various materials, to neutron radiotherapy, for the treatment of certain forms of cancer, all these applications promise to improve our quality of life. To meet the growing need for neutrons, greater demands are being made on the neutron 'generator' technology, demands for improved neutron output and reliability at reduced physical sizes and costs. One such example in the field of borehole neutron generators, where, through neutron activation analysis, the elemental composition, concentration and location in the surrounding borehole media can be ascertained. These generators, which commonly rely on the fusion of deuterium (D) and tritium (T) at energies of the order of one hundred thousand Volts, seem to defy their physical limitations to provide neutron outputs approaching a billion per second in packages no greater than two inches in diameter. In an attempt to answer this demand, we, at Lawrence Berkeley National Laboratory (LBNL), have begun developing a new generation of neutron generators making use of recent developments in ion source technology. The specific application which motivates this development is in the environmental monitoring field, where pollutants and their concentrations in the subsurface must be assessed. To achieve the desired direction of low-level concentrations and obtain a better directional sensitivity, a neutron output of 109 to 1010 D-T neutrons per second was targeted for generator package which can fit inside a ~5 cm diameter borehole. To accomplish this performance, a radio-frequency (RF)- driven ion source developed at LBNL was adapted to the requirements of this application. The advantages of this type of ion source are its intrinsic ability to tailor the delivery of RF power to the ion source and therefore control the neutron output (pulse width, repetition rate and magnitude) while operating at low pressures (~5 mTorr). In the experimental testing presented herein, a prototype, 5 cm-diameter, inductively driven ion source has produced unsaturated hydrogen beam current densities in excess of 1 A/cm2 and monatomic species fractions in excess of 90%. This satisfactory performance, with respect to the targeted neutron output, was achieved with a 2 MHz, 60 kW pulse of RF to produce a ~20?s plasma pulse at <100 Hz.

Perkins, Luke Torrilhon

184

78 FR 21567 - Installation of Radiation Alarms for Rooms Housing Neutron Sources  

Federal Register 2010, 2011, 2012, 2013, 2014

...NRC-2011-0251] Installation of Radiation Alarms for Rooms Housing Neutron Sources...regulations to require the installation of radiation alarms for rooms housing neutron sources...regulations to require installation of radiation alarms for rooms housing neutron...

2013-04-11

185

General Electric PETtrace cyclotron as a neutron source for boron neutron capture therapy  

Microsoft Academic Search

This research investigates the use of a PETtrace cyclotron produced by General Electric (GE) as a neutron source for boron neutron capture therapy (BNCT). The GE PETtrace was chosen for this investigation because this type of cyclotron is popular among nuclear pharmacies and clinics in many countries; it is compact and reliable; it produces protons with energies high enough to

Andrey Bosko

2005-01-01

186

Efficiency calibration of a large-area neutron detector by using Am\\/Be neutron source  

Microsoft Academic Search

Neutron detection efficiency for a long wedge-shaped plastic scintillation detector was measured by using the Am\\/Be neutron source. The overall efficiency attains 23% at around 2 MeV and decreases to 15% at about 5 MeV. The experimental results are in agreement with the Monte Carlo simulation calculations.

Q. Y. Hu; Y. L. Ye; Z. H. Li; X. Q. Li; D. X. Jiang; T. Zheng; Q. J. Wang; H. Hua; C. E. Wu; Z. Q. Chen; J. Ying; D. Y. Pang; G. L. Zhang; J. Wang

2005-01-01

187

The spallation neutron source SINQ and related dosimetry problems  

SciTech Connect

The spallation neutron source SINQ, presently under construction at Switzerland`s Paul Scherrer Institut, will handle the highest proton current of any comparable facility in the world: a continuous beam of 1.5 mA, 590 MeV protons from an isochronous ring cyclotron. For the users, SINQ as a neutron source should resemble closely a medium flux research reactor; the presence of high and medium energy particles creates new technical problems in design and operation. The engineering design for the major components is based on the results of neutronic calculations, using a code package built around the HETC program. At present, opportunities to verify the theoretical calculations experimentally are very limited. Safety factors have to be built in which conflict with the optimization of SINQ as a neutron source. To benchmark the calculational methods, a wide ranging diagnostic system will be required.

Janett, A.; Atchison, F.; Bauer, G.S. [Paul Scherrer Inst., Villigen PSI (Switzerland)

1994-12-31

188

Nuclear and dosimetric features of an isotopic neutron source  

NASA Astrophysics Data System (ADS)

A multisphere neutron spectrometer was used to determine the features of a 239PuBe neutron source that is used to operate the ESFM-IPN Subcritical Reactor. To determine the source main features it was located a 100 cm from the spectrometer which was a 6LiI(Eu) scintillator and 2, 3, 5, 8, 10 and 12 in.-diameter polyethylene spheres. Count rates obtained with the spectrometer were unfolded using the NSDUAZ code and neutron spectrum, total fluence, and ambient dose equivalent were determined. A Monte Carlo calculation was carried out to estimate the spectrum and integral features being less than values obtained experimentally due to the presence of 241Pu in the Pu used to fabricate the source. Actual neutron yield and the mass fraction of 241Pu was estimated.

Vega-Carrillo, H. R.; Hernndez-Dvila, V. M.; Rivera, T.; Snchez, A.

2014-02-01

189

Intrinsic neutron source strengths in uranium solutions  

NASA Astrophysics Data System (ADS)

Neutron production rates for 5 pct. enriched uranyl fluoride and 93 pct. uranyl nitrate solutions have been measured using a high efficiency neutron well counter. Measurements were made for both solution types as a function of sample volume. These results were extrapolated to zero sample volume to eliminate sample size effects, such as multiplication and absorption. For the 5 pct. enriched uranyl fluoride solution, a neutron production rate of 0.0414 (+ or -) 0.0041 n/s/ml was measured; for the 93 pct. enriched uranyl nitrate solution, a neutron production rate of 0.0232 (+ or -) 0.0023 n/s/ml was measured. The biggest uncertainty is in measuring the detector efficiency, and further work on this aspect of the experiment is planned. Calculations for the neutron production rates based on measured thick-target (alpha, n) production rates and the known alpha stopping powers are in reasonable agreement with the data for the uranyl nitrate solution, but are in poor agreement with the data for the uranyl fluoride solution.

Anderson, R. E.; Robba, A. A.; Seale, R. L.; Rutherford, D. A.; Butterfield, K. B.; Brunson, G. S.

190

Optimal Neutron Source & Beam Shaping Assembly for Boron Neutron Capture Therapy  

SciTech Connect

There were three objectives to this project: (1) The development of the 2-D Swan code for the optimization of the nuclear design of facilities for medical applications of radiation, radiation shields, blankets of accelerator-driven systems, fusion facilities, etc. (2) Identification of the maximum beam quality that can be obtained for Boron Neutron Capture Therapy (BNCT) from different reactor-, and accelerator-based neutron sources. The optimal beam-shaping assembly (BSA) design for each neutron source was also to e obtained. (3) Feasibility assessment of a new neutron source for NCT and other medical and industrial applications. This source consists of a state-of-the-art proton or deuteron accelerator driving and inherently safe, proliferation resistant, small subcritical fission assembly.

J. Vujic; E. Greenspan; W.E. Kastenber; Y. Karni; D. Regev; J.M. Verbeke, K.N. Leung; D. Chivers; S. Guess; L. Kim; W. Waldron; Y. Zhu

2003-04-30

191

GEM-based thermal neutron beam monitors for spallation sources  

NASA Astrophysics Data System (ADS)

The development of new large area and high flux thermal neutron detectors for future neutron spallation sources, like the European Spallation Source (ESS) is motivated by the problem of 3He shortage. In the framework of the development of ESS, GEM (Gas Electron Multiplier) is one of the detector technologies that are being explored as thermal neutron sensors. A first prototype of GEM-based thermal neutron beam monitor (bGEM) has been built during 2012. The bGEM is a triple GEM gaseous detector equipped with an aluminum cathode coated by 1 ?m thick B4C layer used to convert thermal neutrons to charged particles through the 10B(n,7Li)? nuclear reaction. This paper describes the results obtained by testing a bGEM detector at the ISIS spallation source on the VESUVIO beamline. Beam profiles (FWHMx=31 mm and FWHMy=36 mm), bGEM thermal neutron counting efficiency (?1%), detector stability (3.45%) and the time-of-flight spectrum of the beam were successfully measured. This prototype represents the first step towards the development of thermal neutrons detectors with efficiency larger than 50% as alternatives to 3He-based gaseous detectors.

Croci, G.; Claps, G.; Caniello, R.; Cazzaniga, C.; Grosso, G.; Murtas, F.; Tardocchi, M.; Vassallo, E.; Gorini, G.; Horstmann, C.; Kampmann, R.; Nowak, G.; Stoermer, M.

2013-12-01

192

Body composition to climate change studies - the many facets of neutron induced prompt gamma-ray analysis  

SciTech Connect

In-vivo body composition analysis of humans and animals and in-situ analysis of soil using fast neutron inelastic scattering and thermal neutron capture induced prompt-gamma rays have been described. By measuring carbon (C), nitrogen (N) and oxygen (O), protein, fat and water are determined. C determination in soil has become important for understanding below ground carbon sequestration process in the light of climate change studies. Various neutron sources ranging from radio isotopic to compact 14 MeV neutron generators employing the associated particle neutron time-of-flight technique or micro-second pulsing were implemented. Gamma spectroscopy using recently developed digital multi-channel analyzers has also been described.

Mitra,S.

2008-11-17

193

Neutron powder diffraction at a pulsed neutron source: a study of resolution effects  

Microsoft Academic Search

The General Purpose Powder Diffractometer (GPPD), a high resolution ( d\\/d = 0.002) time-of-flight instrument, exhibits a resolution function that is almost independent of d-spacing. Some of the special properties of time-of-flight scattering data obtained at a pulsed neutron source will be discussed. A method is described that transforms wavelength dependent data, obtained at a pulsed neutron source, so that

J. Jr. Faber; R. L. Hitterman

1985-01-01

194

Inertial electrostatic confinement (IEC) neutron sources  

Microsoft Academic Search

Inertial electrostatic confinement (IEC) is one of the earliest plasma confinement concepts, having first been suggested by P.T. Farnsworth in the 1950s. The concept involves a simple apparatus of concentric spherical electrostatic grids or a combination of grids and magnetic fields. An electrostatic structure is formed from the confluence of electron or ion beams. Gridded IEC systems have demonstrated neutron

R. A. Nebel; D. C. Barnes; E. J. Caramana; R. D. Janssen; W. D. Nystrom; T. N. Tiouririne; B. C. Trent; G. H. Miley; J. Javedani

1995-01-01

195

Lithium neutron producing target for BINP accelerator-based neutron source.  

PubMed

Pilot innovative accelerator-based neutron source for neutron capture therapy is under construction now at the Budker Institute of Nuclear Physics, Novosibirsk, Russia. One of the main elements of the facility is lithium target, that produces neutrons via threshold (7)Li(p,n)(7)Be reaction at 25 kW proton beam with energies 1.915 or 2.5 MeV. In the present report, the results of experiments on neutron producing target prototype are presented, the results of calculations of hydraulic resistance for heat carrier flow and lithium layer temperature are shown. Calculation showed that the lithium target could run up to 10 mA proton beam before melting. Choice of target variant is substantiated. Program of immediate necessary experiments is described. Target design for neutron source constructed at BINP is presented. Manufacturing the neutron producing target up to the end of 2004 and obtaining a neutron beam on BINP accelerator-based neutron source are planned during 2005. PMID:15308150

Bayanov, B; Belov, V; Kindyuk, V; Oparin, E; Taskaev, S

2004-11-01

196

Epithermal Neutron Source for Neutron Resonance Spectroscopy (NRS) using High Intensity, Short Pulse Lasers  

SciTech Connect

A neutron source for neutron resonance spectroscopy (NRS) has been developed using high intensity, short pulse lasers. This measurement technique will allow for robust measurements of interior ion temperature of laser-shocked materials and provide insight into equation of state (EOS) measurements. The neutron generation technique uses protons accelerated by lasers off of Cu foils to create neutrons in LiF, through (p,n) reactions with {sup 7}Li and {sup 19}F. The distribution of the incident proton beam has been diagnosed using radiochromic film (RCF). This distribution is used as the input for a (p,n) neturon prediction code which is compared to experimentally measured neutron yields. From this calculation, a total fluence of 1.8 x 10{sup 9} neutrons is infered, which is shown to be a reasonable amount for NRS temperature measurement.

Higginson, D P; McNaney, J M; Swift, D C; Bartal, T; Hey, D S; Pape, S L; Mackinnon, A; Mariscal, D; Nakamura, H; Nakanii, N; Beg, F N

2010-04-22

197

Source-Specific Neutron Detection Efficiencies of the TAMU Neutron Ball  

NASA Astrophysics Data System (ADS)

In this paper, we report neutron detection efficiencies for the TAMU Neutron Ball located at the Cyclotron Institute at Texas A&M University. The results discussed are for symmetric reactions of 70Zn, 64Zn and 64Ni at a beam energy of 35 MeV/nucleon. The overall neutron detection efficiency was found to be approximately 70%. We also briefly discuss the process of quasi-projectile (QP) reconstruction. The HIPSE-SIMON reaction simulation and de-excitation code is used in conjunction with a software filter which simulates the geometric and energetic acceptances of the Neutron Ball to provide QT (quasi-target) and QP-specific neutron detection efficiencies. These source-specific efficiencies can be used to estimate the number of free neutrons to associate with the QP during reconstruction of experimental data. With this information it is possible to study the decay processes of well-defined, exotic forms of nuclear matter.

Zarrella, Andrew; Marini, Paola; McIntosh, Alan B.; Cammarata, Paul; Heilborn, Lauren; Mabiala, Justin; May, Larry W.; Raphelt, Andrew; Yennello, Sherry

2013-03-01

198

Radio-isotopic calibration of the Late Eocene - Early Oligocene geomagnetic polarity time scale  

NASA Astrophysics Data System (ADS)

The Geomagnetic Polarity Time Scale (GPTS) has been the subject of several revisions over the last few decades, with a trend toward increasing reliance on astronomically tuned age models over traditional radio-isotopic calibration. In the 2012 Geological Time Scale (GTS12) a comparison between radio-isotopic and astronomical age models for the GPTS yielded partially divergent results, with discrepancies of up to 0.4 Myr in the age of magnetic reversals around the Eocene - Oligocene transition (Vandenberghe et al., 2012). Radio-isotopic constraints on the age of Late Eocene - Early Oligocene magnetic reversals are available from two key sedimentary successions which host datable volcanic tuffs: the marine record of the Umbria-Marche basin in Italy, and the terrestrial White River Group of North America, however concerns have been raised regarding both the accuracy of dates obtained from these successions, and the reliability of their magnetic polarity records (Hilgen and Kuiper, 2009). Here we present a fully integrated radio-isotopic and magnetostratigraphic dataset from the Late Eocene - Early Oligocene North American terrestrial succession with the aim of assessing the accuracy and precision of numerical ages derived from the GPTS. We developed a magnetic polarity record for two partially overlapping sections: Flagstaff Rim in Wyoming and Toadstool Geologic Park in Nebraska, which together provide coverage for the time interval between 36-31 Myr (C16n.2n - C12n) and calibrated this record using an age model based on 14 Pb/U weighted mean ID-TIMS dates obtained on zircons from primary air fall tuffs. The uncertainty of our age model includes random and systematic components for all radio-isotopic tie-points, as well as estimated uncertainties in the stratigraphic position of both the magnetic reversals and the dated tuffs. Our Pb/U dates are 0.4 - 0.8 Myr younger than previously published Ar/Ar data (Swisher and Prothero,1990, recalculated to 28.201 Myr for Fish Canyon sanidine). This, together with the detection of a previously unreported normal polarity zone in the Flagstaff Rim section, correlative to C15n, greatly reduces previously reported discrepancies in the correlation of marine and terrestrial records of the Eocene - Oligocene transition. Our interpolated magnetic reversal dates have uncertainties of 0.05 - 0.10 Myr, are consistent with relatively constant spreading rates for the South Atlantic magnetic anomaly profile of Cande and Kent (1992), and are in good agreement with the astronomically tuned time scale of Paelike et al (2006). A comparison with the astronomically tuned GTS12 record reveals a systematic discrepancy of ca. + 0.3 Myr for Late Eocene reversals. Cande, S.K., Kent, D.V. (1992), Journal of Geophysical Research - Solid Earth, 97, 13917-13951 Hilgen F.J., Kuiper, K.F. (2009) , Geological Society of America Special Papers, 452, 139-148 Paelike H., Norris, R.D., Herrle, J.O., Wilson, P.A., Coxall, H.K., Lear, C.H., Shackleton, N.J., Tripati, A.K., Wade, B.S. (2006), Science, 314, 1894-1898 Swisher, C.C., Prothero, D.R. (1990), Science, 249, 760-762 Vandenberghe N., Hilgen, F.J., Speijer, R.P. (2012), in Gradstein, F.M., Ogg, J.G., Schmitz, M.D., Ogg, G.M. (eds.) The Geologic Time Scale 2012, vol.2, 855-921

Sahy, Diana; Fischer, Anne U.; Condon, Daniel J.; Terry, Dennis O.; Hiess, Joe; Abels, Hemmo; Huesing, Silja K.; Kuiper, Klaudia F.

2013-04-01

199

High Intensity Accelerator and Neutron Source in China  

NASA Astrophysics Data System (ADS)

High intensity Accelerator is being studied all over world for numerous applications, which includes the waste transmutation, spallation neutron source and material irradiation facilities. The R/D activities of the technology of High intensity accelerator are also developed in China for some year, and have some good facilities around China. This paper will reports the status of some high intensity accelerators and neutron source in China, which including ADS/RFQ; CARR; CSNS; PKUNIFTY & CPHS. This paper will emphatically report the Compact Pulsed Hadron Source (CPHS) led by the Department of Engineering Physics of Tsinghua University in Beijing, China.

Guan, Xialing; Wei, J.; Loong, Chun

2011-06-01

200

Materials for cold neutron sources: Cryogenic and irradiation effects  

Microsoft Academic Search

Materials for the construction of cold neutron sources must satisfy a range of demands. The cryogenic temperature and irradiation create a severe environment. Candidate materials are identified and existing cold sources are briefly surveyed to determine which materials may be used. Aluminum- and magnesium-based alloys are the preferred materials. Existing data for the effects of cryogenic temperature and near-ambient irradiation

1990-01-01

201

Gyrotron-driven high current ECR ion source for boron-neutron capture therapy neutron generator  

NASA Astrophysics Data System (ADS)

Boron-neutron capture therapy (BNCT) is a perspective treatment method for radiation resistant tumors. Unfortunately its development is strongly held back by a several physical and medical problems. Neutron sources for BNCT currently are limited to nuclear reactors and accelerators. For wide spread of BNCT investigations more compact and cheap neutron source would be much more preferable. In present paper an approach for compact D-D neutron generator creation based on a high current ECR ion source is suggested. Results on dense proton beams production are presented. A possibility of ion beams formation with current density up to 600 mA/cm2 is demonstrated. Estimations based on obtained experimental results show that neutron target bombarded by such deuteron beams would theoretically yield a neutron flux density up to 61010 cm-2/s. Thus, neutron generator based on a high-current deuteron ECR source with a powerful plasma heating by gyrotron radiation could fulfill the BNCT requirements significantly lower price, smaller size and ease of operation in comparison with existing reactors and accelerators.

Skalyga, V.; Izotov, I.; Golubev, S.; Razin, S.; Sidorov, A.; Maslennikova, A.; Volovecky, A.; Kalvas, T.; Koivisto, H.; Tarvainen, O.

2014-12-01

202

Core Vessel Insert Handling Robot for the Spallation Neutron Source  

SciTech Connect

The Spallation Neutron Source provides the world's most intense pulsed neutron beams for scientific research and industrial development. Its eighteen neutron beam lines will eventually support up to twenty-four simultaneous experiments. Each beam line consists of various optical components which guide the neutrons to a particular instrument. The optical components nearest the neutron moderators are the core vessel inserts. Located approximately 9 m below the high bay floor, these inserts are bolted to the core vessel chamber and are part of the vacuum boundary. They are in a highly radioactive environment and must periodically be replaced. During initial SNS construction, four of the beam lines received Core Vessel Insert plugs rather than functional inserts. Remote replacement of the first Core Vessel Insert plug was recently completed using several pieces of custom-designed tooling, including a highly complicated Core Vessel Insert Robot. The design of this tool are discussed.

Graves, Van B [ORNL; Dayton, Michael J [ORNL

2011-01-01

203

BNL ACTIVITIES IN ADVANCED NEUTRON SOURCE DEVELOPMENT: PAST AND PRESENT  

SciTech Connect

Brookhaven National Laboratory has been involved in advanced neutron sources almost from its inception in 1947. These efforts have mainly focused on steady state reactors beginning with the construction of the first research reactor for neutron beams, the Brookhaven Graphite Research Reactor. This was followed by the High Flux Beam Reactor that has served as the design standard for all the subsequent high flux reactors constructed worldwide. In parallel with the reactor developments BNL has focused on the construction and use of high energy proton accelerators. The first machine to operate over 1 GeV in the world was the Cosmotron. The machine that followed this, the AGS, is still operating and is the highest intensity proton machine in the world and has nucleated an international collaboration investigating liquid metal targets for next generation pulsed spallation sources. Early work using the Cosmotron focused on spallation product studies for both light and heavy elements into the several GeV proton energy region. These original studies are still important today. In the sections below the authors discuss the facilities and activities at BNL focused on advanced neutron sources. BNL is involved in the proton source for the Spallation Neutron source, spectrometer development at LANSCE, target studies using the AGS and state-of-the-art neutron detector development.

HASTINGS,J.B.; LUDEWIG,H.; MONTANEZ,P.; TODOSOW,M.; SMITH,G.C.; LARESE,J.Z.

1998-06-14

204

A thermal neutron source imager using coded apertures  

SciTech Connect

To facilitate the process of re-entry vehicle on-site inspections, it would be useful to have an imaging technique which would allow the counting of deployed multiple nuclear warheads without significant disassembly of a missile`s structure. Since neutrons cannot easily be shielded without massive amounts of materials, they offer a means of imaging the separate sources inside a sealed vehicle. Thermal neutrons carry no detailed spectral information, so their detection should not be as intrusive as gamma ray imaging. A prototype device for imaging at close range with thermal neutrons has been constructed using an array of {sup 3}He position-sensitive gas proportional counters combined with a uniformly redundant coded aperture array. A sealed {sup 252}Cf source surrounded by a polyethylene moderator is used as a test source. By means of slit and pinhole experiments, count rates of image-forming neutrons (those which cast a shadow of a Cd aperture on the detector) are compared with the count rates for background neutrons. The resulting ratio, which limits the available image contrast, is measured as a function of distance from the source. The envelope of performance of the instrument is defined by the contrast ratio, the angular resolution, and the total count rate as a function of distance from the source. These factors will determine whether such an instrument could be practical as a tool for treaty verification.

Vanier, P.E.; Forman, L.; Selcow, E.C.

1995-08-01

205

Considerations for an Intense Source of Ultracold Neutrons at the European Long Pulse Spallation Source  

NASA Astrophysics Data System (ADS)

While intense reactor based sources of ultra-cold neutrons have been in operation for approximately three decades, it is only in the last few years that practical sources of UCN have been realized at spallation sources. Existing and proposed spallation based UCN sources employ two distinct strategies. In the first, the UCN converter (superfluid 4He, or solid D2) is placed in the immediate vicinity of the spallation target. In the second, a converter (usually superfluid He) is placed at the output end of a cold neutron guide fed by the spallation target cold source. Both of these approaches are considered in relation to the European Long Pulse Spallation Source.

Pendlebury, J. M.; Greene, G. L.

206

Active Neutron-Based Interrogation System with D-D Neutron Source for Detection of Special Nuclear Materials  

NASA Astrophysics Data System (ADS)

The detection of special nuclear materials (SNM) is an important issue for nuclear security. The interrogation systems used in a sea port and an airport are developed in the world. The active neutron-based interrogation system is the one of the candidates. We are developing the active neutron-based interrogation system with a D-D fusion neutron source for the nuclear security application. The D-D neutron source is a compact discharge-type fusion neutron source called IEC (Inertial-Electrostatic Confinement fusion) device which provides 2.45 MeV neutrons. The nuclear materials emit the highenergy neutrons by fission reaction. High-energy neutrons with energies over 2.45 MeV amount to 30% of all the fission neutrons. By using the D-D neutron source, the detection of SNMs is considered to be possible with the attention of fast neutrons if there is over 2.45 MeV. Ideally, neutrons at En>2.45 MeV do not exist if there is no nuclear materials. The detection of fission neutrons over 2.45 MeV are hopeful prospect for the detection of SNM with a high S/N ratio. In the future, the experiments combined with nuclear materials and a D-D neutron source will be conducted. Furthermore, the interrogation system will be numerically investigated by using nuclear materials, a D-D neutron source, and a steel container.

Takahashi, Y.; Misawa, T.; Yagi, T.; Pyeon, C. H.; Kimura, M.; Masuda, K.; Ohgaki, H.

2015-10-01

207

Neutron source reconstruction from pinhole imaging at National Ignition Facility  

NASA Astrophysics Data System (ADS)

The neutron imaging system at the National Ignition Facility (NIF) is an important diagnostic tool for measuring the two-dimensional size and shape of the neutrons produced in the burning deuterium-tritium plasma during the ignition stage of inertial confinement fusion (ICF) implosions at NIF. Since the neutron source is small (100 ?m) and neutrons are deeply penetrating (>3 cm) in all materials, the apertures used to achieve the desired 10-?m resolution are 20-cm long, single-sided tapers in gold. These apertures, which have triangular cross sections, produce distortions in the image, and the extended nature of the pinhole results in a non-stationary or spatially varying point spread function across the pinhole field of view. In this work, we have used iterative Maximum Likelihood techniques to remove the non-stationary distortions introduced by the aperture to reconstruct the underlying neutron source distributions. We present the detailed algorithms used for these reconstructions, the stopping criteria used and reconstructed sources from data collected at NIF with a discussion of the neutron imaging performance in light of other diagnostics.

Volegov, P.; Danly, C. R.; Fittinghoff, D. N.; Grim, G. P.; Guler, N.; Izumi, N.; Ma, T.; Merrill, F. E.; Warrick, A. L.; Wilde, C. H.; Wilson, D. C.

2014-02-01

208

Neutron source reconstruction from pinhole imaging at National Ignition Facility.  

PubMed

The neutron imaging system at the National Ignition Facility (NIF) is an important diagnostic tool for measuring the two-dimensional size and shape of the neutrons produced in the burning deuterium-tritium plasma during the ignition stage of inertial confinement fusion (ICF) implosions at NIF. Since the neutron source is small (?100 ?m) and neutrons are deeply penetrating (>3 cm) in all materials, the apertures used to achieve the desired 10-?m resolution are 20-cm long, single-sided tapers in gold. These apertures, which have triangular cross sections, produce distortions in the image, and the extended nature of the pinhole results in a non-stationary or spatially varying point spread function across the pinhole field of view. In this work, we have used iterative Maximum Likelihood techniques to remove the non-stationary distortions introduced by the aperture to reconstruct the underlying neutron source distributions. We present the detailed algorithms used for these reconstructions, the stopping criteria used and reconstructed sources from data collected at NIF with a discussion of the neutron imaging performance in light of other diagnostics. PMID:24593362

Volegov, P; Danly, C R; Fittinghoff, D N; Grim, G P; Guler, N; Izumi, N; Ma, T; Merrill, F E; Warrick, A L; Wilde, C H; Wilson, D C

2014-02-01

209

Plasma based 14 MeV neutron sources  

NASA Astrophysics Data System (ADS)

The utmost urgency to develop powerful 14 MeV neutron sources is now well understood among fusion community of engineers and material scientists. The time of influence of 14 MeV neutrons upon the fusion reactor components is estimated at 10-20 years and corresponds to a fluence of 1.5-4.5 1022 n/cm2. As yet, no reliable data are available on the behavior of reactor component materials exposed to such a flux. This creates a great deal of uncertainty in the performance and endurance predictions of future fusion reactor main components. The first wall flux from ITER will be approximately 1 MW year/m2 by the time that the choice of materials for DEMO will have to be made. A comparison of the desired flux from DEMO of 10-20 MW year/m2 shows quite clearly that ITER will provide too small a flux and too late in time to contribute usefully to the materials selection process. On the other hand, before DEMO is built, suitable materials for the first wall and other critical reactor elements must be selected. Thus, DEMO cannot be constructed without a wide program of material study (end-of-life, resistivity increase from neutron damage, H, He, dpa production rates, activation of nuclei, etc.) as well as the welds and brazes to be used in the reactor. To realize this program a high-flux neutron source of DT-neutrons, covering a sufficiently large test zone, should be rapidly constructed. At present, a number of proposals for 14 MeV neutron sources are known. Among these are: sources based on the acceleration of ions, interaction of ions with targets, volumetric plasma neutron sources based on tokamaks and mirrors, ``exotic'' schemes using ?-catalysis and lasers. In this paper the advantages and shortcomings of various approaches are discussed, from both the technical feasibility and economic points of view.

Kruglyakov, E. P.

1995-09-01

210

Apparatus for the measurement of total body nitrogen using prompt neutron activation analysis with californium-252.  

PubMed

Details of clinical apparatus designed for the measurement of total body nitrogen (as an indicator of body protein), suitable for the critically ill, intensive-care patient are presented. Californium-252 radio-isotopic neutron sources are used, enabling a nitrogen measurement by prompt neutron activation analysis to be made in 40 min with a precision of +/- 3.2% for a whole body dose equivalent of 0.145 mSv. The advantages of Californium-252 over alternative neutron sources are discussed. A comparison between two irradiation/detection geometries is made, leading to an explanation of the geometry adopted for the apparatus. The choice of construction and shielding materials to reduce the count rate at the detectors and consequently to reduce the pile-up contribution to the nitrogen background is discussed. Salient features of the gamma ray spectroscopy system to reduce spectral distortion from pulse pile-up are presented. PMID:3057210

Mackie, A; Hannan, W J; Smith, M A; Tothill, P

1988-01-01

211

Neutron dosimetry, moderated energy spectrum, and neutron capture therapy for californium-252 medical sources  

NASA Astrophysics Data System (ADS)

Examination of neutron dosimetry for 252Cf has been conducted using calculative and experimental means. Monte Carlo N-Particle (MCNP) transport code was used in a distributed computing environment as a parallel virtual machine (PVM) to determine the absorbed neutron dose and neutron energy spectrum from 252Cf in a variety of clinically relevant materials. Herein, a Maxwellian spectrum was used to model the 252Cf neutron emissions within these materials. 252Cf mixed-field dosimetry of Applicator Tube (AT) type sources was measured using 1.0 and 0.05 cm3 tissue-equivalent ion chambers and a miniature GM counter. A dosimetry protocol was formulated similar that of ICRU 45. The 252Cf AT neutron dosimetry was determined in the cylindrical coordinate system formalism recommended by the AAPM Task Group 43. These results demonstrated the overwhelming dependence of dosimetry on the source geometry factor as there was no significant neutron attenuation within the source or encapsulation. Gold foils and TLDs were used to measure the thermal flux in the vicinity of 252Cf AT sources to compare with the results calculated using MCNP. As the fast neutron energy spectrum did not markedly changed at increasing distances from the AT source, neutron dosimetry results obtained with paired ion chambers using fixed sensitivity factors agreed well with MCNP results and those in the literature. Calculations of moderated 252Cf neutron energy spectrum with various loadings of 10B and 157Gd were performed, in addition to analysis of neutron capture therapy dosimetry with these isotopes. Radiological concerns such as personnel exposure and shielding of 252Cf emissions were examined. Feasibility of a high specific-activity 252Cf HDR source was investigated through radiochemical and metallurgical studies using stand-ins such as Tb, Gd and 249Cf. Issues such as capsule burst strength due to helium production for a variety of proposed HDR sources were addressed. A recommended 252Cf source strength of at least 1mg was necessary for fabrication of a 252Cf HDR source.

Rivard, Mark Joseph

212

Energy-Resolving Neutron Transmission Radiography at the ISIS Pulsed Spallation Source With a High-Resolution Neutron Counting Detector  

Microsoft Academic Search

Neutron transmission radiography can be strongly enhanced by adding spectroscopic data spatially correlated with the attenuation coefficient. This can now be achieved at pulsed neutron sources, utilizing a neutron detector with high spatial and temporal resolution. The energy of transmitted neutrons can be recovered from their time-of-flight, simultaneously with the acquisition of the transmission radiographic image by a pixelated detector.

Anton S. Tremsin; Jason B. McPhate; Winfried A. Kockelmann; John V. Vallerga; Oswald H. W. Siegmund; W. Bruce Feller

2009-01-01

213

Energy-resolving neutron transmission radiography at the ISIS pulsed spallation source with a high-resolution neutron counting detector  

Microsoft Academic Search

Neutron transmission radiography can be strongly enhanced by adding spectroscopic data spatially correlated with the attenuation coefficient. This can now be achieved at pulsed neutron sources, utilizing a neutron detector with high spatial and temporal resolution. The energy of transmitted neutrons can be recovered from their time-of-flight, simultaneously with the acquisition of the transmission radiographic image by a pixilated detector.

Anton S. Tremsin; Jason B. McPhate; Winfried A. Kockelmann; John V. Vallerga; Oswald H. W. Siegmund; W. Bruce Feller

2008-01-01

214

Feasibility of sealed D-T neutron generator as neutron source for liver BNCT and its beam shaping assembly.  

PubMed

This paper involves the feasibility of boron neutron capture therapy (BNCT) for liver tumor with four sealed neutron generators as neutron source. Two generators are placed on each side of the liver. The high energy of these emitted neutrons should be reduced by designing a beam shaping assembly (BSA) to make them useable for BNCT. However, the neutron flux decreases as neutrons pass through different materials of BSA. Therefore, it is essential to find ways to increase the neutron flux. In this paper, the feasibility of using low enrichment uranium as a neutron multiplier is investigated to increase the number of neutrons emitted from D-T neutron generators. The neutron spectrum related to our system has a proper epithermal flux, and the fast and thermal neutron fluxes comply with the IAEA recommended values. PMID:24448270

Liu, Zheng; Li, Gang; Liu, Linmao

2014-04-01

215

The new cold neutron chopper spectrometer at the Spallation Neutron Source: design and performance.  

PubMed

The design and performance of the new cold neutron chopper spectrometer (CNCS) at the Spallation Neutron Source in Oak Ridge are described. CNCS is a direct-geometry inelastic time-of-flight spectrometer, designed essentially to cover the same energy and momentum transfer ranges as IN5 at ILL, LET at ISIS, DCS at NIST, TOFTOF at FRM-II, AMATERAS at J-PARC, PHAROS at LANSCE, and NEAT at HZB, at similar energy resolution. Measured values of key figures such as neutron flux at sample position and energy resolution are compared between measurements and ray tracing Monte Carlo simulations, and good agreement (better than 20% of absolute numbers) has been achieved. The instrument performs very well in the cold and thermal neutron energy ranges, and promises to become a workhorse for the neutron scattering community for quasielastic and inelastic scattering experiments. PMID:21895276

Ehlers, G; Podlesnyak, A A; Niedziela, J L; Iverson, E B; Sokol, P E

2011-08-01

216

The new cold neutron chopper spectrometer at the Spallation Neutron Source: Design and performance  

NASA Astrophysics Data System (ADS)

The design and performance of the new cold neutron chopper spectrometer (CNCS) at the Spallation Neutron Source in Oak Ridge are described. CNCS is a direct-geometry inelastic time-of-flight spectrometer, designed essentially to cover the same energy and momentum transfer ranges as IN5 at ILL, LET at ISIS, DCS at NIST, TOFTOF at FRM-II, AMATERAS at J-PARC, PHAROS at LANSCE, and NEAT at HZB, at similar energy resolution. Measured values of key figures such as neutron flux at sample position and energy resolution are compared between measurements and ray tracing Monte Carlo simulations, and good agreement (better than 20% of absolute numbers) has been achieved. The instrument performs very well in the cold and thermal neutron energy ranges, and promises to become a workhorse for the neutron scattering community for quasielastic and inelastic scattering experiments.

Ehlers, G.; Podlesnyak, A. A.; Niedziela, J. L.; Iverson, E. B.; Sokol, P. E.

2011-08-01

217

The new cold neutron chopper spectrometer at the Spallation Neutron Source: Design and performance  

SciTech Connect

The design and performance of the new cold neutron chopper spectrometer (CNCS) at the Spallation Neutron Source in Oak Ridge are described. CNCS is a direct-geometry inelastic time-of-flight spectrometer, designed essentially to cover the same energy and momentum transfer ranges as IN5 at ILL, LET at ISIS, DCS at NIST, TOFTOF at FRM-II, AMATERAS at J-PARC, PHAROS at LANSCE, and NEAT at HZB, at similar energy resolution. Measured values of key figures such as neutron flux at sample position and energy resolution are compared between measurements and ray tracing Monte Carlo simulations, and good agreement (better than 20% of absolute numbers) has been achieved. The instrument performs very well in the cold and thermal neutron energy ranges, and promises to become a workhorse for the neutron scattering community for quasielastic and inelastic scattering experiments.

Ehlers, G.; Podlesnyak, A. A.; Niedziela, J. L.; Iverson, E. B. [Neutron Scattering Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Sokol, P. E. [Department of Physics, Indiana University, Bloomington, Indiana 47405 (United States)

2011-08-15

218

The new Cold Neutron Chopper Spectrometer at the Spallation Neutron Source -- Design and Performance  

SciTech Connect

The design and performance of the new cold neutron chopper spectrometer (CNCS) at the Spallation Neutron Source in Oak Ridge are described. CNCS is a direct-geometry inelastic time-of-flight spectrometer, designed essentially to cover the same energy and momentum transfer ranges as IN5 at ILL, LET at ISIS, DCS at NIST, TOFTOF at FRM-II, AMATERAS at J-PARC, PHAROS at LANSCE, and NEAT at HZB, at similar energy resolution. Measured values of key figures such as neutron flux at sample position and energy resolution are compared between measurements and ray tracing Monte Carlo simulations, and good agreement (better than 20% of absolute numbers) has been achieved. The instrument performs very well in the cold and thermal neutron energy ranges, and promises to become a workhorse for the neutron scattering community for quasielastic and inelastic scattering experiments.

Ehlers, Georg [ORNL; Podlesnyak, Andrey A [ORNL; Niedziela, Jennifer L [ORNL; Iverson, Erik B [ORNL; Sokol, Paul E [ORNL

2011-01-01

219

A neutron producing target for BINP accelerator-based neutron source.  

PubMed

An innovative accelerator-based neutron source for BNCT has just started operation at the Budker Institute of Nuclear Physics, Novosibirsk. One of the main elements of the facility is a lithium target producing neutrons via the threshold (7)Li(p,n)(7)Be reaction at 25 kW proton beam with energies of 1.915 MeV or 2.5 MeV. The design of an optimal target and results of the investigation of radiation blistering of the lithium layer were presented at previous NCT Congresses. During the last two years the neutron target has been manufactured, assembled and placed in the facility. Optimization of the target is carried out with the Monte Carlo simulation code MCNP. In this article, the design of the target is discussed, results of all previous investigations are summarized, results of target testing and neutron generation are described, and results of simulation of neutron spectra are presented. PMID:19376729

Bayanov, B; Kashaeva, E; Makarov, A; Malyshkin, G; Samarin, S; Taskaev, S

2009-07-01

220

Proton Driver Linac for the Frankfurt Neutron Source  

SciTech Connect

The Frankfurt Neutron Source at the Stern-Gerlach-Zentrum (FRANZ) will deliver high neutron fluxes in the energy range of 1 to 500 keV. The Activation Mode provides a high averaged neutron flux created by a cw proton beam of up to 5 mA, while in the Compressor Mode intense neutron pulses of 1 ns length are formed with a repetition rate of up to 250 kHz. The Compressor Mode is well-suited for energy-dependent neutron capture measurements using the Time-of-Flight method in combination with a 4{pi} BaF{sub 2} detector array. The design of the proton driver linac for both operation modes is presented. This includes the volume type ion source, the ExB chopper located in the low energy section, the RFQ-IH combination for beam acceleration and the bunch compressor. Finally, the neutron production at the lithium-7 target and the resulting energy spectrum is described.

Wiesner, C.; Chau, L. P.; Dinter, H.; Droba, M.; Heilmann, M.; Joshi, N.; Maeder, D.; Metz, A.; Meusel, O.; Noll, D.; Podlech, H.; Ratzinger, U.; Reichau, H.; Schempp, A.; Schmidt, S.; Schweizer, W.; Volk, K.; Wagner, C. [Institut fuer Angewandte Physik, Goethe-Universitaet, Max-von-Laue-Str. 1, 60438 Frankfurt/Main (Germany); Reifarth, R. [Institut fuer Angewandte Physik, Goethe-Universitaet, Max-von-Laue-Str. 1, 60438 Frankfurt/Main (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany); Mueller, I.

2010-08-04

221

Neutron source investigations in support of the cross section program at the Argonne Fast-Neutron Generator  

Microsoft Academic Search

Experimental methods related to the production of neutrons for cross section studies at the Argonne Fast-Neutron Generator are reviewed. Target assemblies commonly employed in these measurements are described, and some of the relevant physical properties of the neutron source reactions are discussed. Various measurements have been performed to ascertain knowledge about these source reaction that is required for cross section

J. W. Meadows; D. L. Smith

1980-01-01

222

Low Energy Accelerator-Based Neutron Sources for Neutron Capture Therapy  

NASA Astrophysics Data System (ADS)

An epithermal neutron beam design for an accelerator -based neutron source for neutron capture therapy (NCT) has been studied. Calculation shows that, of many possible neutron-producing reactions, the Li-7(p,n)Be-7 and H-3(p,n)He -3 reactions are the more promising reactions for producing high neutron yields for NCT. The total neutron yield from the Li-7(p,n)Be-7 and H-3(p,n)He-3 reactions are 1.5 times 10^{-4} and 2.5 times 10^ {-4} neutrons/proton with 2.5 and 1.77 MeV protons, respectively. For a 20 mA proton beam (typical current has been achieved with Radio Frequency Quadrupole accelerators so far), the total neutron yield would be about 1.8 times 10^ {13} and 3.2 times 10^{13} neutrons/sec for the Li-7(p,n)Be-7 and H-3(p,n)He-3 reactions, respectively. The reactions must be coupled with a moderator to reduce the energy of the neutrons to an acceptable range. A three -dimensional Monte Carlo code (MCNP) was used to predict neutron flux and neutron and gamma doses. The modified moderator assembly consists of a cylindrical moderator surrounded by a cylindrical reflector. Li-6 with 0.05% atomic concentration was determined to be the concentration in the moderator and reflector, for mitigating the production of gamma rays by removing thermal neutrons. For the Li -7(p,n)Be-7 reaction and a 20 mA proton beam, BeO (20 cm thick, 25 cm diameter cylinder) and MgO (85 cm diameter cylinder) appear to be the optimum selection of moderator and reflector materials. The useful neutron (neutron energy > 1 eV) flux in air, calculated at the irradiation position, is 2.0 times 10^9 n/cm^2/s. For the H-3(p,n)He-3 reaction, rm Al_2O _3 as moderator (34 cm thick) and also as reflector material gave the best performance. The useful neutron flux, calculated in air at the irradiation position, is 2.4 times 10^9 n/cm^2/s.

Wu, Hsinshun (Terry).

223

High Flux Isotope Reactor cold neutron source reference design concept  

SciTech Connect

In February 1995, Oak Ridge National Laboratory`s (ORNL`s) deputy director formed a group to examine the need for upgrades to the High Flux Isotope Reactor (HFIR) system in light of the cancellation of the Advanced neutron Source Project. One of the major findings of this study was that there was an immediate need for the installation of a cold neutron source facility in the HFIR complex. In May 1995, a team was formed to examine the feasibility of retrofitting a liquid hydrogen (LH{sub 2}) cold source facility into an existing HFIR beam tube. The results of this feasibility study indicated that the most practical location for such a cold source was the HB-4 beam tube. This location provides a potential flux environment higher than the Institut Laue-Langevin (ILL) vertical cold source and maximizes the space available for a future cold neutron guide hall expansion. It was determined that this cold neutron beam would be comparable, in cold neutron brightness, to the best facilities in the world, and a decision was made to complete a preconceptual design study with the intention of proceeding with an activity to install a working LH{sub 2} cold source in the HFIR HB-4 beam tube. During the development of the reference design the liquid hydrogen concept was changed to a supercritical hydrogen system for a number of reasons. This report documents the reference supercritical hydrogen design and its performance. The cold source project has been divided into four phases: (1) preconceptual, (2) conceptual design and testing, (3) detailed design and procurement, and (4) installation and operation. This report marks the conclusion of the conceptual design phase and establishes the baseline reference concept.

Selby, D.L.; Lucas, A.T.; Hyman, C.R. [and others

1998-05-01

224

Optimization of an accelerator-based epithermal neutron source for neutron capture therapy.  

PubMed

A modeling investigation was performed to choose moderator material and size for creating optimal epithermal neutron beams for BNCT based on a proton accelerator and the (7)Li(p,n)(7)Be reaction as a neutrons source. An optimal configuration is suggested for the beam shaping assembly made from polytetrafluoroethylene and magnesium fluorine to be placed on high current IPPE proton accelerator KG-2.5. Results of calculation were experimentally tested and are in good agreement with measurements. PMID:15308184

Kononov, O E; Kononov, V N; Bokhovko, M V; Korobeynikov, V V; Soloviev, A N; Sysoev, A S; Gulidov, I A; Chu, W T; Nigg, D W

2004-11-01

225

Status report on the cold neutron source of the Garching neutron research facility FRM-II  

Microsoft Academic Search

The new high flux research reactor of the Technical University of Munich (Technische Universitt Mnchen, TUM) will be equipped with a cold neutron source (CNS). The centre of the CNS will be located in the D2O-reflector tank at 400mm from the reactor core axis close to the thermal neutron flux maximum. The power of 4500W developed by the nuclear heating

K. Gobrecht; E. Gutsmiedl; A. Scheuer

2002-01-01

226

Water-extended polyester neutron shield for a 252Cf neutron source.  

PubMed

A Monte Carlo study to determine the shielding features to neutrons of water-extended polyester was carried out. During calculations, (252)Cf and shielding were modelled and the neutron spectra as well as the H(10) were calculated in four sites. The calculation was extended to include a water shielding, the source in vacuum and in air. Besides neutron shielding characteristics, the Kerma in air due to gammas emitted by (252)Cf and due to capture gamma rays in the shielding were included. PMID:17496334

Vega-Carrillo, H R; Manzanares-Acua, E; Hernndez-Dvila, V M; Gallego, E; Lorente, A; Donaire, I

2007-01-01

227

Inertial-Electrostatic Confinement Neutron/Proton Source  

NASA Astrophysics Data System (ADS)

There is considerable demand in the scientific community for a neutron generator with an output of 106-108 neutrons/second (n/s) that can be switched on or off, emit fusion neutrons, be self-calibrating, and offer portable operation. An Inertial Electrostatic Confinement (IEC)-based neutron generator is proposed to meet these needs. In an IEC device, ion beams are injected into a spherical vacuum vessel containing one or more sets of spherical wire grids. A high fusion rate is generated in a dense plasma region created in the center of the innermost grid by intersecting ion beams and the associated potential well structure. Here, we describe a unique configuration, termed the IECGD, where a gaseous discharge in a single-gridded device serves as the ion source. Operation in the newly discovered "Star" discharge mode maximizes the effective grid transmission factor for ions. This configuration, then, provides a simple, rugged, low-cost fusion neutron source, operating in the 106 D-D n/s or 108 D-T n/s range. The extension to an intense MeV proton source is also possible. Experimental results for the IECGD are presented, with a discussion of corresponding theoretical studies using a Vlasov-Poisson solver (IXL) and an electrostatic particle-in-cell code (PDS1).

Miley, G. H.; Javedani, J.; Yamamoto, Y.; Nebel, R.; Nadler, J.; Gu, Y.; Satsangi, A.; Heck, P.

1994-03-01

228

Fission reactor neutron sources for neutron capture therapy--a critical review.  

PubMed

The status of fission reactor-based neutron beams for neutron capture therapy (NCT) is reviewed critically. Epithermal neutron beams, which are favored for treatment of deep-seated tumors, have been constructed or are under construction at a number of reactors worldwide. Some of the most recently constructed epithermal neutron beams approach the theoretical optimum for beam purity. Of these higher quality beams, at least one is suitable for use in high through-put routine therapy. It is concluded that reactor-based epithermal neutron beams with near optimum characteristics are currently available and more can be constructed at existing reactors. Suitable reactors include relatively low power reactors using the core directly as a source of neutrons or a fission converter if core neutrons are difficult to access. Thermal neutron beams for NCT studies with small animals or for shallow tumor treatments, with near optimum properties have been available at reactors for many years. Additional high quality thermal beams can also be constructed at existing reactors or at new, small reactors. Furthermore, it should be possible to design and construct new low power reactors specifically for NCT, which meet all requirements for routine therapy and which are based on proven and highly safe reactor technology. PMID:12749699

Harling, Otto K; Riley, Kent J

2003-01-01

229

Accelerator-based neutron source for boron neutron capture therapy (BNCT) and method  

DOEpatents

A source for boron neutron capture therapy (BNCT) comprises a body of photoneutron emitter that includes heavy water and is closely surrounded in heat-imparting relationship by target material; one or more electron linear accelerators for supplying electron radiation having energy of substantially 2 to 10 MeV and for impinging such radiation on the target material, whereby photoneutrons are produced and heat is absorbed from the target material by the body of photoneutron emitter. The heavy water is circulated through a cooling arrangement to remove heat. A tank, desirably cylindrical or spherical, contains the heavy water, and a desired number of the electron accelerators circumferentially surround the tank and the target material as preferably made up of thin plates of metallic tungsten. Neutrons generated within the tank are passed through a surrounding region containing neutron filtering and moderating materials and through neutron delimiting structure to produce a beam or beams of epithermal neutrons normally having a minimum flux intensity level of 1.0.times.10.sup.9 neutrons per square centimeter per second. Such beam or beams of epithermal neutrons are passed through gamma ray attenuating material to provide the required epithermal neutrons for BNCT use.

Yoon, Woo Y. (Idaho Falls, ID); Jones, James L. (Idaho Falls, ID); Nigg, David W. (Idaho Falls, ID); Harker, Yale D. (Idaho Falls, ID)

1999-01-01

230

Accelerator-based neutron source for boron neutron capture therapy (BNCT) and method  

DOEpatents

A source for boron neutron capture therapy (BNCT) comprises a body of photoneutron emitter that includes heavy water and is closely surrounded in heat-imparting relationship by target material; one or more electron linear accelerators for supplying electron radiation having energy of substantially 2 to 10 MeV and for impinging such radiation on the target material, whereby photoneutrons are produced and heat is absorbed from the target material by the body of photoneutron emitter. The heavy water is circulated through a cooling arrangement to remove heat. A tank, desirably cylindrical or spherical, contains the heavy water, and a desired number of the electron accelerators circumferentially surround the tank and the target material as preferably made up of thin plates of metallic tungsten. Neutrons generated within the tank are passed through a surrounding region containing neutron filtering and moderating materials and through neutron delimiting structure to produce a beam or beams of epithermal neutrons normally having a minimum flux intensity level of 1.0{times}10{sup 9} neutrons per square centimeter per second. Such beam or beams of epithermal neutrons are passed through gamma ray attenuating material to provide the required epithermal neutrons for BNCT use. 3 figs.

Yoon, W.Y.; Jones, J.L.; Nigg, D.W.; Harker, Y.D.

1999-05-11

231

Neutron Radiographic Inspection of Industrial Components using Kamini Neutron Source Facility  

NASA Astrophysics Data System (ADS)

Kamini (Kalpakkam Mini) reactor is a U233 fuelled, demineralised light water moderated and cooled, beryllium oxide reflected, low power (30 kW) nuclear research reactor. This reactor functions as a neutron source with a flux of 1012 n/cm2 s-1 at core centre with facilitates for carrying out neutron radiography, neutron activation analysis and neutron shielding experiments. There are two beam tubes for neutron radiography. The length/diameter ratio of the collimators is about 160 and the aperture size is 220 mm70 mm. Flux at the outer end of the beam tube is 106-107 n/cm2 s. The north end beam tube is for radiography of inactive object while the south side beam tube is for radiography of radioactive objects. The availability of high neutron flux coupled with good collimated beam provides high quality radiographs with short exposure time. The reactor being a unique national facility for neutron radiography has been utilized in the examination of irradiated components, aero engine turbine blades, riveted plates, automobile chain links and for various types of pyro devices used in the space programme. In this paper, an overview of the salient features of this reactor facility for neutron radiography and our experience in the inspection of a variety of industrial components will be given.

Raghu, N.; Anandaraj, V.; Kasiviswanathan, K. V.; Kalyanasundaram, P.

2008-03-01

232

Development of an IEC neutron source for NDE  

SciTech Connect

This paper concerns the development of a neutron so based on the inertial electrostatic confinement (IEC) of a low density fusion plasma in a gridded, spherically-focusing device. With the motivation of using such sources for nondestructive evaluation (NDE) applications, the focus of the development is on : Small size devices, sealed operation with D{sub 2} or D{sub 2}/T{sub 2} mixtures, Power-utilization and neutron-output optimization, and integration into an assay system. In this paper, we describe an experimental system that has been established for the development and testing of IEC neutron sources, and we present preliminary results of tests conducted for 25-cm and 15-cm diameter IEC devices.

Anderl, R.A,; Hartwell, J.K. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States); Nadler, J.H. [Illinois Univ., Urbana, IL (United States). Fusion Studies Lab.

1995-12-01

233

Residual stress measurement using the pulsed neutron source at LANSCE  

SciTech Connect

The presence of residual stress in engineering components can effect their mechanical properties and structural integrity. Neutron diffraction is the only measuring technique which can make spatially resolved non-destructive strain measurements in the interior of components. By recording the change in the crystalline interplanar spacing, elastic strains can be measured for individual lattice reflections. Using a pulsed neutron source, all the lattice reflections are recorded in each measurement which allows anisotropic effects to be studied. Measurements made at the Manuel Lujan Jr Neutron Scattering Centre (LANSCE) demonstrate the potential for stress measurements on a pulsed source and indicate the advantages and disadvantages over measurements made on a reactor. 15 refs., 7 figs.

Bourke, M.A.M.; Goldstone, J.A. (Los Alamos National Lab., NM (USA)); Holden, T.M. (Atomic Energy of Canada Ltd., Chalk River, ON (Canada))

1991-01-01

234

Characterization of neutron sources from spent fuel casks. [Skyshine  

SciTech Connect

In the interim period prior to the acceptance of spent fuel for disposal by the USDOE, utilities are beginning to choose dry cask storage as an alternative to pool re-racking, transshipments, or new pool construction. In addition, the current MRS proposal calls for interim dry storage of consolidated spent fuel in concrete casks. As part of the licensing requirements for these cask storage facilities, calculations are typically necessary to determine the yearly radiation dose received at the site boundary. Unlike wet facilities, neutron skyshine can be an important contribution to the total boundary dose from a dry storage facility. Calculation of the neutron skyshine is in turn heavily dependent on the source characteristics and source model selected for the analysis. This paper presents the basic source characteristics of the spent fuel stored in dry casks and discusses factors that must be considered in evaluating and modeling the radiation sources for the subsequent skyshine calculation. 4 refs., 1 tab.

Parks, C.V.; Pace, J.V. III

1987-01-01

235

Accelerator shield design of KIPT neutron source facility  

SciTech Connect

Argonne National Laboratory (ANL) of the United States and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on the design development of a neutron source facility at KIPT utilizing an electron-accelerator-driven subcritical assembly. Electron beam power is 100 kW, using 100 MeV electrons. The facility is designed to perform basic and applied nuclear research, produce medical isotopes, and train young nuclear specialists. The biological shield of the accelerator building is designed to reduce the biological dose to less than 0.5-mrem/hr during operation. The main source of the biological dose is the photons and the neutrons generated by interactions of leaked electrons from the electron gun and accelerator sections with the surrounding concrete and accelerator materials. The Monte Carlo code MCNPX serves as the calculation tool for the shield design, due to its capability to transport electrons, photons, and neutrons coupled problems. The direct photon dose can be tallied by MCNPX calculation, starting with the leaked electrons. However, it is difficult to accurately tally the neutron dose directly from the leaked electrons. The neutron yield per electron from the interactions with the surrounding components is less than 0.01 neutron per electron. This causes difficulties for Monte Carlo analyses and consumes tremendous computation time for tallying with acceptable statistics the neutron dose outside the shield boundary. To avoid these difficulties, the SOURCE and TALLYX user subroutines of MCNPX were developed for the study. The generated neutrons are banked, together with all related parameters, for a subsequent MCNPX calculation to obtain the neutron and secondary photon doses. The weight windows variance reduction technique is utilized for both neutron and photon dose calculations. Two shielding materials, i.e., heavy concrete and ordinary concrete, were considered for the shield design. The main goal is to maintain the total dose outside the shield boundary at less than 0.5-mrem/hr. The shield configuration and parameters of the accelerator building have been determined and are presented in this paper. (authors)

Zhong, Z.; Gohar, Y. [Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439 (United States)

2013-07-01

236

A Californium-252 Neutron Source for Student Use  

ERIC Educational Resources Information Center

Describes an undergraduate chemistry experiment which utilizes small samples of Californium 252 as a neutron source for the activation of 12 other elements. The students prepare decay curves of the radioactive isotopes and perform nondestructive activation analyses for gram amounts of some elements. (MLH)

Bowen, H. J.

1975-01-01

237

Application of Fusion Neutron Source for Denaturing of Plutonium  

Microsoft Academic Search

Potential of DT fusion neutron source to enhance proliferation resistance properties of plutonium by means of its isotopic denaturing is addressed. The approach is exemplified by denaturing of pure Pu and plutonium of typical LWR spent fuel through transmutation of neptunium. The essential feature of a fusion driven system proposed in the study is a zero mass balance of plutonium:

Alan TAKIBAYEV; Masaki SAITO; Hiroshi SAGARA

2007-01-01

238

OPERATION OF THE SUPERCONDUCTING LINAC AT THE SPALLATION NEUTRON SOURCE  

Microsoft Academic Search

At the Spallation Neutron Source, the first fully operational pulsed superconducting linac has been active for about two years. During this period, stable beam operation at 4.4 K has been achieved with beam for repetition rates up to 15 Hz and 30 Hz at 2.1 K. At the lower temperature 60 Hz RF pulses have been also used. Full beam

Isidoro E Campisi; Fabio Casagrande; Mark Champion; Mark T Crofford; Matthew P Howell; Yoon W Kang; Sang-Ho Kim; Zafer Kursun; Peter Ladd; Daniel S Stout; William Herb Strong

2007-01-01

239

Operation of the Superconducting Linac at the Spallation Neutron Source  

Microsoft Academic Search

At the Spallation Neutron Source, the first fully operational pulsed superconducting linac has been active for about two years. During this period, stable beam operation at 4.4 K has been achieved with beam for repetition rates up to 15 Hz and 30 Hz at 2.1 K. At the lower temperature 60 Hz RF pulses have been also used. Full beam

Isidoro E Campisi; Fabio Casagrande; Mark S Champion; M. Crofford; M. Howell; Y. Kang; S. H. Kim; Z. Kursun; P. Ladd; D. Stout; W. Strong

2008-01-01

240

R&D for the Spallation Neutron Source mercury target  

Microsoft Academic Search

An overview of the research and development program for the Spallation Neutron Source (SNS) is presented. The materials-related efforts in target development are emphasized in order to provide a perspective for a number of specialized papers that are included in these proceedings. We give a brief introduction and historical sketch of the SNS project. Part of the materials R&D consists

L. K Mansur; T. A Gabriel; J. R Haines; D. C Lousteau

2001-01-01

241

Materials for spallation neutron sources, with emphasis on SNS facility  

Microsoft Academic Search

The materials requirements in a high-power spallation neutron source like the SNS are particularly demanding. Materials at the target station are of special concern; these include the containment vessel and protective shroud for the mercury target material, beam windows, support structures, moderator housings, and beam tubes. The material chosen for the mercury containment vessel is Type 316 stainless steel (316SS).

Mansur

1999-01-01

242

Material issues relating to high power spallation neutron sources  

NASA Astrophysics Data System (ADS)

Innovative researches using neutrons are being performed at the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), in which a mercury target system is installed for MW-class pulse spallation neutron sources. In order to produce neutrons by the spallation reaction, proton beams are injected into the mercury target. At the moment, when the intense proton beam hits the target, pressure waves are generated in mercury because of the abrupt heat deposition. The pressure waves interact with the target vessel, leading to negative pressure that may cause cavitation along the vessel wall, i.e. on the interface between liquid and solid metals. On the other hand, the structural materials are subjected to irradiation damage due to protons and neutrons, very high cycle fatigue damages and so-called "liquid metal embrittlement". That is, the structural materials must be said to be exposed to the extremely severe environments. In the paper, research and development relating to the material issues in the high power spallation neutron sources that has been performed so far at J-PARC is summarized.

Futakawa, M.

2015-02-01

243

Evaluation of thermal neutron irradiation field using a cyclotron-based neutron source for alpha autoradiography.  

PubMed

It is important to measure the microdistribution of (10)B in a cell to predict the cell-killing effect of new boron compounds in the field of boron neutron capture therapy. Alpha autoradiography has generally been used to detect the microdistribution of (10)B in a cell. Although it has been performed using a reactor-based neutron source, the realization of an accelerator-based thermal neutron irradiation field is anticipated because of its easy installation at any location and stable operation. Therefore, we propose a method using a cyclotron-based epithermal neutron source in combination with a water phantom to produce a thermal neutron irradiation field for alpha autoradiography. This system can supply a uniform thermal neutron field with an intensity of 1.710(9) (cm(-2)s(-1)) and an area of 40mm in diameter. In this paper, we give an overview of our proposed system and describe a demonstration test using a mouse liver sample injected with 500mg/kg of boronophenyl-alanine. PMID:24560850

Tanaka, H; Sakurai, Y; Suzuki, M; Masunaga, S; Mitsumoto, T; Kinashi, Y; Kondo, N; Narabayashi, M; Nakagawa, Y; Watanabe, T; Fujimoto, N; Maruhashi, A; Ono, K

2014-06-01

244

Optimizing moderator dimensions for neutron scattering at the spallation neutron source.  

PubMed

In this work, we investigate the effect of neutron moderator dimensions on the performance of neutron scattering instruments at the Spallation Neutron Source (SNS). In a recent study of the planned second target station at the SNS facility, we have found that the dimensions of a moderator play a significant role in determining its surface brightness. A smaller moderator may be significantly brighter over a smaller viewing area. One of the immediate implications of this finding is that for modern neutron scattering instrument designs, moderator dimensions and brightness have to be incorporated as an integrated optimization parameter. Here, we establish a strategy of matching neutron scattering instruments with moderators using analytical and Monte Carlo techniques. In order to simplify our treatment, we group the instruments into two broad categories: those with natural collimation and those that use neutron guide systems. For instruments using natural collimation, the optimal moderator selection depends on the size of the moderator, the sample, and the moderator brightness. The desired beam divergence only plays a role in determining the distance between sample and moderator. For instruments using neutron optical systems, the smallest moderator available that is larger than the entrance dimension of the closest optical element will perform the best (assuming, as is the case here that smaller moderators are brighter). PMID:24387465

Zhao, J K; Robertson, J L; Herwig, Kenneth W; Gallmeier, Franz X; Riemer, Bernard W

2013-12-01

245

Optimizing moderator dimensions for neutron scattering at the spallation neutron source  

NASA Astrophysics Data System (ADS)

In this work, we investigate the effect of neutron moderator dimensions on the performance of neutron scattering instruments at the Spallation Neutron Source (SNS). In a recent study of the planned second target station at the SNS facility, we have found that the dimensions of a moderator play a significant role in determining its surface brightness. A smaller moderator may be significantly brighter over a smaller viewing area. One of the immediate implications of this finding is that for modern neutron scattering instrument designs, moderator dimensions and brightness have to be incorporated as an integrated optimization parameter. Here, we establish a strategy of matching neutron scattering instruments with moderators using analytical and Monte Carlo techniques. In order to simplify our treatment, we group the instruments into two broad categories: those with natural collimation and those that use neutron guide systems. For instruments using natural collimation, the optimal moderator selection depends on the size of the moderator, the sample, and the moderator brightness. The desired beam divergence only plays a role in determining the distance between sample and moderator. For instruments using neutron optical systems, the smallest moderator available that is larger than the entrance dimension of the closest optical element will perform the best (assuming, as is the case here that smaller moderators are brighter).

Zhao, J. K.; Robertson, J. L.; Herwig, Kenneth W.; Gallmeier, Franz X.; Riemer, Bernard W.

2013-12-01

246

Optimizing moderator dimensions for neutron scattering at the spallation neutron source  

SciTech Connect

In this work, we investigate the effect of neutron moderator dimensions on the performance of neutron scattering instruments at the Spallation Neutron Source (SNS). In a recent study of the planned second target station at the SNS facility, we have found that the dimensions of a moderator play a significant role in determining its surface brightness. A smaller moderator may be significantly brighter over a smaller viewing area. One of the immediate implications of this finding is that for modern neutron scattering instrument designs, moderator dimensions and brightness have to be incorporated as an integrated optimization parameter. Here, we establish a strategy of matching neutron scattering instruments with moderators using analytical and Monte Carlo techniques. In order to simplify our treatment, we group the instruments into two broad categories: those with natural collimation and those that use neutron guide systems. For instruments using natural collimation, the optimal moderator selection depends on the size of the moderator, the sample, and the moderator brightness. The desired beam divergence only plays a role in determining the distance between sample and moderator. For instruments using neutron optical systems, the smallest moderator available that is larger than the entrance dimension of the closest optical element will perform the best (assuming, as is the case here that smaller moderators are brighter)

Zhao, J. K.; Robertson, J. L.; Herwig, Kenneth W.; Gallmeier, Franz X.; Riemer, Bernard W. [Instrument and Source Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)] [Instrument and Source Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2013-12-15

247

Accelerator-based intense neutron source for materials R D  

SciTech Connect

Accelerator-based neutron sources for R D of materials in nuclear energy systems, including fusion reactors, can provide sufficient neutron flux, flux-volume, fluence and other attractive features for many aspects of materials research. The neutron spectrum produced from the D-Li reaction has been judged useful for many basic materials research problems, and to be a satisfactory approximation to that of the fusion process. The technology of high-intensity linear accelerators can readily be applied to provide the deuteron beam for the neutron source. Earlier applications included the Los Alamos Meson Physics Facility and the Fusion Materials Irradiation Test facility prototype. The key features of today's advanced accelerator technology are presented to illustrate the present state-of-the-art in terms of improved understanding of basic physical principles and engineering technique, and to show how these advances can be applied to present demands in a timely manner. These features include how to produce an intense beam current with the high quality required to minimize beam losses along the accelerator and transport system that could cause maintenance difficulties, by controlling the beam emittance through proper choice of the operating frequency, balancing of the forces acting on the beam, and realization in practical hardware. A most interesting aspect for materials researchers is the increased flexibility and opportunities for experimental configurations that a modern accelerator-based source could add to the set of available tools. 8 refs., 5 figs.

Jameson, R.A.

1990-01-01

248

New perspectives from new generations of neutron sources  

NASA Astrophysics Data System (ADS)

Since the early 1950s the vital multidisciplinary progress in understanding condensed matter is, in a substantial fraction, based on results of neutron scattering experiments. Neutron scattering is an inherently intensity limited method and after 50 years of considerable advanceprimarily achieved by improving the scattering instrumentsthe maturation of the technique of pulsed spallation sources now opens up the way to provide more neutrons with improved cost and energy efficiency. A quantitative analysis of the figure-of-merit of the specialized instruments for pulsed source operation shows that up to 2 orders of magnitude intensity gains can be achieved in the next decade, with the advent of high power spallation sources. The first stations on this road, the MW class short pulse spallation sources SNS in the USA (under commissioning), and J-PARC in Japan (under construction) will be followed by the 5 MW long pulse European Spallation Source (ESS). Further progress, that can be envisaged on the longer term, could amount to as much as another factor of 10 improvement. To cite this article: F. Mezei, C. R. Physique 8 (2007).

Mezei, Ferenc

2007-09-01

249

A Microfabricated Deuterium Ion Source for Compact Neutron Generators  

NASA Astrophysics Data System (ADS)

Active neutron interrogation is generally accepted as a reliable means of detecting the illicit transportation of special nuclear materials, in particular highly enriched uranium. The development of portable active neutron interrogation systems for field detection applications could be facilitated by the use of a new deuterium ion source which has the potential to advance many of the performance limiting aspects of exiting compact, accelerator-driven neutron generators. The ion source being investigated is a gated array of sharp metal tips that uses high electric fields to generate deuterium ion currents through the physical processes of field ionization and field desorption. The deuterium ions produced by the source are extracted and used to drive a D-D (or D-T) fusion reaction to create neutrons. The basic microstructure for the ion source array is derived from modern semiconductor microfabrication technology for field emitter arrays, though many structural modifications have been made in an attempt to reach the required operating fields of the ion generation processes. Pulsed (field desorption) and d.c. (field ionization) tests conducted with each array design type developed thus far indicate a steady improvement in array tip operating fields. Field ionization studies were conducted with arrays at source temperatures of 77 K and 293 K. Newly developed arrays have demonstrated field ionization currents upwards of 50 nA, which is roughly 50% of the maximum ion production possible, as presently fabricated. Neutron production by field ionization was demonstrated for the first time from the microfabricated arrays. A maximum neutron yield of 95 n/s (6300 n/s/cm2 of array active area) was observed from a 1.5 mm2 array using a D-D fusion reaction at -90 kV. Field desorption studies at 77 K and 293 K were conducted in parallel with field ionization testing. To date, the arrays have consistently demonstrated the field desorption of deuterium ions from array tip surfaces. The number of deuterium ions desorbed was quantified and found to be significantly less than predicted. The low deuterium ion yields have been attributed to the presence of surface contaminants that inhibit the adsorption of deuterium. As such, thermal and hydrogen plasma cleaning methods are being investigated to condition the array tip surfaces. For both field ionization and field desorption, improved array designs that can achieve higher tip operating fields are required before predicted neutron yields (>109 n/s/cm2) can be demonstrated.

Johnson, Benjamin Bargsten

250

The Spallation Neutron Source: A powerful tool for materials research  

SciTech Connect

When completed in 2006, the Spallation Neutron Source (SNS) will use an accelerator to produce the most intense beams of pulsed neutrons in the world. This unique facility is being built by a collaboration of six US Department of Energy laboratories and will serve a diverse community of users drawn from academia, industry, and government labs. The project continues on schedule and within budget, with commissioning and installation of all systems going well. Installation of 14 state-of-the-art instruments is under way, and design work is being completed for several others. These new instruments will enable inelastic and elastic-scattering measurements across a broad range of science such as condensed-matter physics, chemistry, engineering materials, biology, and beyond. Neutron Science at SNS will be complemented by research opportunities at several other facilities under way at Oak Ridge National Laboratory.

Mason, Thom [ORNL; Anderson, Ian S [ORNL; Ankner, John Francis [ORNL; Egami, Takeshi [ORNL; Ekkebus, Allen E [ORNL; Herwig, Kenneth W [ORNL; Hodges, Jason P [ORNL; Horak, Charlie M [ORNL; Horton, Linda L [ORNL; Klose, Frank Richard [ORNL; Mesecar, Andrew D. [University of Illinois, Chicago; Myles, Dean A A [ORNL; Ohl, M. [Forschungszentrum Julich, Julich, Germany; Zhao, Jinkui [ORNL

2006-01-01

251

Spallation ultracold neutron source of superfluid helium below 1 K.  

PubMed

For the production of high-density ultracold neutrons (UCNs), we placed 0.8 K superfluid helium in a cold neutron moderator. We resolved previous heat-load problems in the spallation neutron source that were particularly serious below 1 K. With a proton-beam power of 400 MeV1 ?A, a UCN production rate of 4 UCN cm(-3) s(-1) at the maximum UCN energy of E(c)=210 neV and a storage lifetime of 81 s were obtained. A cryogenic test showed that the production rate can be increased by a factor of 10 with the same storage lifetime by increasing the proton-beam power as well as (3)He pumping speed. PMID:22540705

Masuda, Yasuhiro; Hatanaka, Kichiji; Jeong, Sun-Chan; Kawasaki, Shinsuke; Matsumiya, Ryohei; Matsuta, Kensaku; Mihara, Mototsugu; Watanabe, Yutaka

2012-03-30

252

Shielding and neutronic optimization of the National Spallation Neutron Source (NSNS)  

SciTech Connect

Studies are now underway to establish initial design characteristics for the pulsed neutron source NSNS facility and to optimize the design. In this paper the methodology of calculation is presented together with the calculated facility characteristics. Optimization studies are discussed and initial results shown. This paper addresses the target station of the NSNS.

Charlton, L.A.; Barnes, J.M.; Johnson, J.O.; Gabriel, T.A.

1997-05-01

253

An Ultracold Neutron Source for 1. Introduction to Ultracold Neutrons (UCN)  

E-print Network

interacts with free neutron (UCN) target. 132Sn current 5e17 /s UCN density 2e4 /cc meter-long target sigma: gravity: V=mgh (h in source #12;UCN Physics fundamental interactions of UCN EDM gravity beta-decay nnbar oscillations

Martin, Jeff

254

Time-of-Flight Neutron Diffraction for Long Pulse Neutron Sources  

Microsoft Academic Search

The Time-of-Flight (TOF) method for neutron diffraction was proposed half a century ago by Buras and Leciejewicz [1] as a very efficient alternative to the crystal monochromator technique most often used at that time. It was the advent of the first pulsed spallation sources that has shown how farsighted this proposal was the diffractometers naturally based on the TOF method

F. Mezei; M. Russina; Gy. Kali

2012-01-01

255

Ion source antenna development for the Spallation Neutron Source  

Microsoft Academic Search

The operational lifetime of a radio-frequency (rf) ion source is generally governed by the length of time the insulating structure protecting the antenna survives during exposure to the plasma. Coating the antenna with a thin layer of insulating material is a common means of extending the life of such antennas. When low-power\\/low-duty factor rf excitation is employed, antenna lifetimes of

R. F. Welton; M. P. Stockli; Y. Kang; M. Janney; R. Keller; R. W. Thomae; T. Schenkel; S. Shukla

2002-01-01

256

Capabilities of a DT tokamak fusion neutron source for driving a spent nuclear fuel transmutation reactor  

Microsoft Academic Search

The capabilities of a DT fusion neutron source for driving a spent nuclear fuel transmutation reactor are characterized by identifying limits on transmutation rates that would be imposed by tokamak physics and engineering limitations on fusion neutron source performance. The need for spent nuclear fuel transmutation and the need for a neutron source to drive subcritical fission transmutation reactors are

W. M. Stacey

2001-01-01

257

Time-Resolved High Resolution Neutron Imaging Studies at the ORNL Spallation Neutron Source  

SciTech Connect

Our evaluation of a high-resolution digital imaging detector capable of providing millisecond time resolution and high sensitivity for neutrons is presented. This detector is a modified version of the high-resolution -ray imager developed previously at Radiation Monitoring Devices, Inc. (RMD, Inc.), and consists of an Electron Multiplying Charge Coupled Device (EMCCD) attached to a neutron-sensitive scintillator via a fiberoptic taper. By virtue of its internal gain, the EMCCD permits high speed readout without introducing additional noise, thereby enabling high frame rate operation with an enhanced signal-to-noise ratio (SNR). Detector sensitivity is enhanced through the use of a back-thinned EMCCD, which provides high quantum efficiency over a typical emission range for many neutron-sensitive scintillators. Preliminary evaluations conducted at the Liquids Reflectometer beam port of the Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory (ORNL) demonstrate that this new detector has the sensitivity to detect individual neutrons and the acquisition speed to perform energy-selective imaging with a temporal resolution of milliseconds. While substantial improvements in timing and imaging performance are planned, this prototype detector has already generated the first ever images of the SNS Liquids Reflectometer beam profile and was also used to demonstrate a technique for obtaining Bragg edge transmission imaging using energy-selective neutrons. The preliminary data, along with the detector design, evaluation, and planned developments are discussed in this paper.

Nagarkar, Vivek [RMD, Inc.; Penumadu, Dayakar [University of Tennessee, Knoxville (UTK); Shestakova,, Irina [RMD, Inc.; Thacker, Samta [RMD, Inc.; Miller, Stuart [RMD, Inc.; Ankner, John Francis [ORNL; Bilheux, Hassina Z [ORNL; Halbert, Candice E [ORNL

2009-01-01

258

The Neutron Science TeraGrid Gateway, a TeraGrid Science Gateway to Support the Spallation Neutron Source  

E-print Network

1 The Neutron Science TeraGrid Gateway, a TeraGrid Science Gateway to Support the Spallation Neutron Source John W. Cobb* , Al Geist* , James A. Kohl* , Stephen D. Miller , Peter F. Peterson] is entering its operational phase. An ETF science gateway effort is the Neutron Science TeraGrid Gateway (NSTG

Vazhkudai, Sudharshan

259

Post irradiation examination of the Spallation Neutron Source target vessels  

SciTech Connect

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is an accelerator-based pulsed neutron source that produces high-energy spallation neutrons by bombarding liquid mercury flowing through a stainless steel target vessel. During operation the proton beam and spallation neutrons produce radiation damage in the AISI 316L austenitic stainless steel target vessel and water-cooled shroud. The beam pulses also cause rapid heating of the liquid mercury, which may produce cavitation erosion damage on the inner surface of the target vessel. The cavitation erosion rate is thought to be highly sensitive to beam power and predicted to be the primary life-limiting factor of target vessel. Though mitigation of cavitation erosion and radiation damage to the target vessel will be a critical for successful high-power operation of the SNS facility, the effects of radiation damage and cavitation erosion to target vessels in liquid metal spallation systems are not well known. Therefore preparations are being undertaken to perform post irradiation examination (PIE) of the liquid mercury target vessel and water-cooled shroud after end-of-life occurs. An overview of the planned PIE for the SNS target vessel is presented here, including proposed techniques for specimen acquisition and subsequent material properties characterization.

McClintock, David A [ORNL; Ferguson, Phillip D [ORNL; Mansur, Louis K [ORNL

2010-01-01

260

Actinide/beryllium neutron sources with reduced dispersion characteristics  

DOEpatents

Neutron source comprising a composite, said composite comprising crystals comprising BeO and AmBe13, and an excess of beryllium, wherein the crystals have an average size of less than 2 microns; the size distribution of the crystals is less than 2 microns; and the beryllium is present in a 7-fold to a 75-fold excess by weight of the amount of AmBe13; and methods of making thereof.

Schulte, Louis D.

2012-08-14

261

Design of a tritium breeding blanket for volumetric neutron source  

Microsoft Academic Search

A water-cooled and austenitic stainless-steel-structured breeding blanket system is designed for a volumetric neutron source (VNS), based on a steady-state tokamak device. The designed VNS with super-conducting coils has a 4.5 m main radius and a total of 300 MW in fusion power. It yields the tritium consumption of approximately 10 kg per year with 50% availability. It is unrealistic

Y. Asaoka; Y. Ogawa; K. Okano; N. Inoue; Y. Murakami; K. Tomabechi; T. Yamamoto; T. Yoshida

1998-01-01

262

Inertial electrostatic confinement fusion neutron source R & D and issues  

Microsoft Academic Search

An inertial electrostatic confinement (IEC) fusion is the scheme of injecting the ions and electrons toward the spherical center, trapping both species in the electrostatic self-field and giving rise to fusion reactions in the dense core. An IEC is expected to have wide application from a small neutron source to a D-³He fusion reactor. Hirsch reported 10⁹ n\\/s deuterium-tritium (D-T)

Masami Ohnishi; Yasushi Yamamoto; Mitsunori Hasegawa

1997-01-01

263

Superconducting prototype cavities for the Spallation Neutron Source (SNS) project  

Microsoft Academic Search

The Spallation Neutron Source project includes a superconducting linac section in the energy range from 186 MeV to 1000 MeV. For this energy range two types of cavities are needed with geometrical ? values of ?=0.61 and ?=0.81. An aggressive cavity prototyping program is being pursued at Jefferson Lab, which calls for fabricating and testing four ?=0.61 cavities and two

Gianluigi Ciovati; P. Kneisel; J. Brawley; R. Bundy; I. Campisi; K. Davis; K. Macha; D. Machie; J. Mammosser; S. Morgan; R. Sundelin; L. Turlington; K. Wilson; M. Doleans; S. H. Kim; D. Mangra; D. Barni; C. Pagani; P. Pierini; K. Matsumoto; R. Mitchell; D. Schrage; R. Parodi; J. Sekutowicz; P. Ylae-Oijala

2001-01-01

264

Flow blockage analysis for the advanced neutron source reactor  

Microsoft Academic Search

The Advanced Neutron Source (ANS) reactor was designed to provide a research tool with capabilities beyond those of any existing reactors. One portion of its state-of-the-art design required high-speed fluid flow through narrow channels between the fuel plates in the core. Experience with previous reactors has shown that fuel plate damage can occur when debris becomes lodged at the entrance

T. K. Stovall; J. A. Crabtree; D. K. Felde; J. E. Park

1996-01-01

265

Conceptual design for one megawatt spallation neutron source at Argonne  

Microsoft Academic Search

A feasibility study of a spallation neutron source based on a rapid cycling synchrotron which delivers a proton beam of 2 GeV in energy and 0.5 mA time-averaged current at a 30-Hz repetition rate is presented. The lattice consists of 90-degree phase advance FODO cells with dispersion-free straight sections, and has a three-fold symmetry. The ring magnet system will be

Y. Chio; J. Bailey; B. Brown; F. Brumwell; J. Carpenter; K. Crawford; D. Horan; D. Jerng; R. Kelb; A. Knox; R. Kustom; E. Lessner; D. McGhee; F. Mills; H. Moe; R. Nielsen; C. Potts; A. Rauchas; K. Thompson

1993-01-01

266

EURAC: A liquid target neutron spallation source using cyclotron technology  

NASA Astrophysics Data System (ADS)

Euratom/JRC Ispra led some years ago the design of an accelerator based neutron spallation source EURAC, with special emphasis as a fusion material testing device. DENIM was involved in the development of the last version of this source. EURAC proposes to use a beam of 600 MeV or 1.5 GeV protons, produced by an effective and low cost ring cyclotron with a current of 6 mA impinging in a liquid lead, or lead-bismuth, target. It will use an advanced cyclotron technology which can be implemented in the next future, in the line of the actual technology of the upgraded SIN-type cyclotron. The adjacent rows to the target correspond to the lead, or Li17Pb83, cooled channels where the samples will be located. The available volumes there were shown enough for material testing purposes. Here, proposal of using those experimental areas to introduce small masses of radioactive wastes for testing of transmutation in spallation source is made. In addition, extrapolation of present conceptual design to make available larger volumes under flexible conditions seems to be possible. Neutrons leaking from the test zone drive a subcritical booster (< 10 MW) which could provide a thermal neutron flux trap with a liquid hidrogen moderator in the center.

Perlado, J. M.; Mnguez, E.; Sanz, J.; Piera, M.

1995-09-01

267

Design Issues for an Intense Neutron Calibration Source for ITER  

NASA Astrophysics Data System (ADS)

ITER needs to be able to calibrate its neutron diagnostics, in-situ. We are developing a design for a compact 10^11 n/sec DD neutron source using multiple deuterium ion beams impacting on a thin-film deuterated liquid propane jet target. This will be substantially higher flux than any commercial non-radioisotope neutron source. The system will be cooled by liquid nitrogen, and the beam source is differentially pumped from the target region, with no intervening windows. It must operate for weeks at a time, without maintenance, inside of ITER, with a minimum of interfering structures. We envision the substantial power (< 100 kW), cooling, and gas feed will enter the ITER vessel from the outside, via umbilical lines. The system should be movable, ideally fitting on the end of an ITER manipulator arm. Possible solutions to the overall design issues will be discussed. This work is supported by the Office of Fusion Energy Sciences, and DOE/LANL contract DE-AC52-06NA25396 and LANL-ITER contract FIA-09-035.

Wurden, G. A.; Park, Jaeyoung; Hwang, Y. S.

2010-11-01

268

The advanced neutron source research and development plan  

SciTech Connect

The Advanced Neutron Source (ANS) is being designed as a user-oriented neutron research laboratory centered around the most intense continuous beams of thermal and subthermal neutrons in the world (an order of magnitude more intense than beams available from the most advanced existing reactors). The ANS will be built around a new research reactor of 330-MW fission power, producing an unprecedented peak thermal flux of >7 {center_dot} 10{sup 19} {center_dot} m{sup -2} {center_dot} s{sup -1}. Primarily a research facility, the ANS will accommodate more than 1000 academic, industrial, and government researchers each year. They will conduct basic research in all branches of science as well as applied research leading to better understanding of new materials, including high temperature super conductors, plastics, and thin films. Some 48 neutron beam stations will be set up in the ANS beam rooms and the neutron guide hall for neutron scattering and for fundamental and nuclear physics research. There also will be extensive facilities for materials irradiation, isotope production, and analytical chemistry. The top level work breakdown structure (WBS) for the project. As noted in this figure, one component of the project is a research and development (R&D) program (WBS 1.1). This program interfaces with all of the other project level two WBS activities. Because one of the project guidelines is to meet minimum performance goals without relying on new inventions, this R&D activity is not intended to produce new concepts to allow the project to meet minimum performance goals. Instead, the R&D program will focus on the four objectives described.

Selby, D.L.

1995-08-01

269

Elemental composition in sealed plutonium-beryllium neutron sources.  

PubMed

Five sealed plutonium-beryllium (PuBe) neutron sources from various manufacturers were disassembled. Destructive chemical analyses for recovered PuBe materials were conducted for disposition purposes. A dissolution method for PuBe alloys was developed for quantitative plutonium (Pu) and beryllium (Be) assay. Quantitation of Be and trace elements was performed using plasma based spectroscopic instruments, namely inductively coupled plasma mass spectrometry (ICP-MS) and atomic emission spectrometry (ICP-AES). Pu assay was accomplished by an electrochemical method. Variations in trace elemental contents among the five PuBe sources are discussed. PMID:25464182

Xu, N; Kuhn, K; Gallimore, D; Martinez, A; Schappert, M; Montoya, D; Lujan, E; Garduno, K; Tandon, L

2014-10-22

270

Accelerator-based epithermal neutron sources for boron neutron capture therapy of brain tumors.  

PubMed

This paper reviews the development of low-energy light ion accelerator-based neutron sources (ABNSs) for the treatment of brain tumors through an intact scalp and skull using boron neutron capture therapy (BNCT). A major advantage of an ABNS for BNCT over reactor-based neutron sources is the potential for siting within a hospital. Consequently, light-ion accelerators that are injectors to larger machines in high-energy physics facilities are not considered. An ABNS for BNCT is composed of: (1) the accelerator hardware for producing a high current charged particle beam, (2) an appropriate neutron-producing target and target heat removal system (HRS), and (3) a moderator/reflector assembly to render the flux energy spectrum of neutrons produced in the target suitable for patient irradiation. As a consequence of the efforts of researchers throughout the world, progress has been made on the design, manufacture, and testing of these three major components. Although an ABNS facility has not yet been built that has optimally assembled these three components, the feasibility of clinically useful ABNSs has been clearly established. Both electrostatic and radio frequency linear accelerators of reasonable cost (approximately 1.5 M dollars) appear to be capable of producing charged particle beams, with combinations of accelerated particle energy (a few MeV) and beam currents (approximately 10 mA) that are suitable for a hospital-based ABNS for BNCT. The specific accelerator performance requirements depend upon the charged particle reaction by which neutrons are produced in the target and the clinical requirements for neutron field quality and intensity. The accelerator performance requirements are more demanding for beryllium than for lithium as a target. However, beryllium targets are more easily cooled. The accelerator performance requirements are also more demanding for greater neutron field quality and intensity. Target HRSs that are based on submerged-jet impingement and the use of microchannels have emerged as viable target cooling options. Neutron fields for reactor-based neutron sources provide an obvious basis of comparison for ABNS field quality. This paper compares Monte Carlo calculations of neutron field quality for an ABNS and an idealized standard reactor neutron field (ISRNF). The comparison shows that with lithium as a target, an ABNS can create a neutron field with a field quality that is significantly better (by a factor of approximately 1.2, as judged by the relative biological effectiveness (RBE)-dose that can be delivered to a tumor at a depth of 6cm) than that for the ISRNF. Also, for a beam current of 10 mA, the treatment time is calculated to be reasonable (approximately 30 min) for the boron concentrations that have been assumed. PMID:12749700

Blue, Thomas E; Yanch, Jacquelyn C

2003-01-01

271

Measurement of uranium and plutonium in solid waste by passive photon or neutron counting and isotopic neutron source interrogation  

SciTech Connect

A summary of the status and applicability of nondestructive assay (NDA) techniques for the measurement of uranium and plutonium in 55-gal barrels of solid waste is reported. The NDA techniques reviewed include passive gamma-ray and x-ray counting with scintillator, solid state, and proportional gas photon detectors, passive neutron counting, and active neutron interrogation with neutron and gamma-ray counting. The active neutron interrogation methods are limited to those employing isotopic neutron sources. Three generic neutron sources (alpha-n, photoneutron, and /sup 252/Cf) are considered. The neutron detectors reviewed for both prompt and delayed fission neutron detection with the above sources include thermal (/sup 3/He, /sup 10/BF/sub 3/) and recoil (/sup 4/He, CH/sub 4/) proportional gas detectors and liquid and plastic scintillator detectors. The instrument found to be best suited for low-level measurements (< 10 nCi/g) is the /sup 252/Cf Shuffler. The measurement technique consists of passive neutron counting followed by cyclic activation using a /sup 252/Cf source and delayed neutron counting with the source withdrawn. It is recommended that a waste assay station composed of a /sup 252/Cf Shuffler, a gamma-ray scanner, and a screening station be tested and evaluated at a nuclear waste site. 34 figures, 15 tables.

Crane, T.W.

1980-03-01

272

Advanced Neutron Source: Plant Design Requirements. Revision 4  

SciTech Connect

The Advanced Neutron Source will be a new world-class facility for research using hot, thermal, cold, and ultra-cold neutrons. The heart of the facility will be a 330-MW (fission), heavy-water cooled and heavy-water moderated reactor. The reactor will be housed in a central reactor building, with supporting equipment located in an adjoining reactor support building. An array of cold neutron guides will fan out into a large guide hall, housing about 30 neutron research stations. Appropriate office, laboratory, and shop facilities will be included to provide a complete facility for users. The ANS is scheduled to begin operation at the Oak Ridge National Laboratory early in the next decade. This PDR document defines the plant-level requirements for the design, construction, and operation of ANS. It also defines and provides input to the individual System Design Description (SDD) documents. Together, this PDR document and the set of SDD documents will define and control the baseline configuration of ANS.

Not Available

1990-07-01

273

Methods for lipid nanostructure investigation at neutron and synchrotron sources  

NASA Astrophysics Data System (ADS)

A lipid membrane is a main component of biological membranes. Contemporary bionanotechnologies use phospholipids and ceramides as basic components of drugs and cosmetic preparations. Phospholipids-based nanoparticles are used as drug carriers. Effective development of bionanotechnologies in Russia calls for creation of physical methods to diagnose the particle nanostructure which would be promising for application in pharmacology. Radiation with wavelengths of 1-10 is an adequate instrument for detecting the nanostructure of lipid bi- and monolayers. The review deals with methods that apply neutron scattering and synchrotron radiation for studying nanostructures of lipid membranes, phospholipid nanoparticles, and phospholipid monolayers on a water surface by techniques of diffraction, small-angle scattering, and reflectometry. The importance of the mutually complementary application of neutron and synchrotron radiation for solving urgent problems of membrane biophysics, microbiology, dermapharmacology, and bionanotechnologies is demonstrated by particular examples of studies of phospholipid membranes and ceramide-based membranes. The efficiency of development and application of new methods for solving urgent problems of biophysics is shown. The review is written on the basis of results obtained over the period of 1999-2010 at the Joint Institute for Nuclear Research (JINR) Laboratory of Neutron Physics in collaboration with the Pharmaceutical Departments of universities of France (Paris-Sud, Chatenay Malabry) and Germany (Martin Luther University, Halle). The experiments were performed at various European and Russian neutron and synchrotron sources.

Kiselev, M. A.

2011-03-01

274

Computational Benchmark Calculations Relevant to the Neutronic Design of the Spallation Neutron Source (SNS)  

SciTech Connect

The Spallation Neutron Source (SNS) will provide an intense source of low-energy neutrons for experimental use. The low-energy neutrons are produced by the interaction of a high-energy (1.0 GeV) proton beam on a mercury (Hg) target and slowed down in liquid hydrogen or light water moderators. Computer codes and computational techniques are being benchmarked against relevant experimental data to validate and verify the tools being used to predict the performance of the SNS. The LAHET Code System (LCS), which includes LAHET, HTAPE ad HMCNP (a modified version of MCNP version 3b), have been applied to the analysis of experiments that were conducted in the Alternating Gradient Synchrotron (AGS) facility at Brookhaven National Laboratory (BNL). In the AGS experiments, foils of various materials were placed around a mercury-filled stainless steel cylinder, which was bombarded with protons at 1.6 GeV. Neutrons created in the mercury target, activated the foils. Activities of the relevant isotopes were accurately measured and compared with calculated predictions. Measurements at BNL were provided in part by collaborating scientists from JAERI as part of the AGS Spallation Target Experiment (ASTE) collaboration. To date, calculations have shown good agreement with measurements.

Gallmeier, F.X.; Glasgow, D.C.; Jerde, E.A.; Johnson, J.O.; Yugo, J.J.

1999-11-14

275

Design and Applications of a {sup 252}Cf Cold Neutron Source  

SciTech Connect

The goal was to design a source of cold neutrons from such sources as {sup 252}Cf, {sup 241}Am-Be, {sup 244}Cm-Be, or {sup 124}Sb-Be and to find the limitations when such a source is applied to neutron activation analysis. Here, cold neutrons are neutrons with a kinetic energy < 0.01 eV. The initial kinetic energy of most of the neutrons produced from the decay of the {sup 252}Cf nucleus lies in the range from 0.5 to 10 MeV, so moderation is necessary to produce a significant quantity of cold neutrons from these initial neutrons. The same is true for the other three neutron sources. The general design that was selected for the cold neutron source has two moderation regions, and the geometry was restricted to cylindrical symmetry with the sample region along the cylindrical axis. The moderation regions may have different temperatures and may contain different moderating materials. The design tasks are then to find the optimum geometry, moderating materials, and moderating temperatures. A cold neutron flux in the sample region of 2.7 x 10 {sup -3} cold neutrons per source neutron is obtainable in a {sup 252}Cf cold neutron source that has polyethylene as the cold and thermal moderator or with trimethylbenzene as the cold moderator and polyethylene as the thermal moderator. The neutron fluxes obtained are probably within 10{percent} of the fluxes that would be obtained in an actual cold neutron source that is based on the model used. This flux of cold neutrons is adequate for sensitive prompt and delayed neutron activation analysis measurements. The results show that a useful flux of cold neutrons can be obtained from small amounts of {sup 252}Cf, {sup 241}Am, {sup 244}Cm, or {sup 124}Sb.

Elijah Johnson; Larry Robinson; Li Zhao

2000-11-12

276

Neutron source in the MCNPX shielding calculating for electron accelerator driven facility  

SciTech Connect

Argonne National Laboratory (ANL) of USA and Kharkov Inst. of Physics and Technology (KIPT) of Ukraine have been collaborating on the design development of an experimental neutron source facility. It is an accelerator driven system (ADS) utilizing a subcritical assembly driven by electron accelerator. The facility will be utilized for performing basic and applied nuclear researches, producing medical isotopes, and training young nuclear specialists. Monte Carlo code MCNPX has been utilized as a design tool due to its capability to transport electrons, photons, and neutrons at high energies. However the facility shielding calculations with MCNPX need enormous computational resources and the small neutron yield per electron makes sampling difficulty for the Monte Carlo calculations. A method, based on generating and utilizing neutron source file, was proposed and tested. This method reduces significantly the required computer resources and improves the statistics of the calculated neutron dose outside the shield boundary. However the statistical errors introduced by generating the neutron source were not directly represented in the results, questioning the validity of this methodology, because an insufficiently sampled neutron source can cause error on the calculated neutron dose. This paper presents a procedure for the validation of the generated neutron source file. The impact of neutron source statistic on the neutron dose is examined by calculating the neutron dose as a function of the number of electron particles used for generating the neutron source files. When the value of the calculated neutron dose converges, it means the neutron source has scored sufficient records and statistic does not have apparent impact on the calculated neutron dose. In this way, the validity of neutron source and the shield analyses could be verified. (authors)

Zhong, Z.; Gohar, Y. [Nuclear Engineering Div., Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

2012-07-01

277

Neutron characterization study for D-T, p-7Li neutron sources with new BCA based direct collision coupling method  

NASA Astrophysics Data System (ADS)

The T(D,n)4He and 7Li(p,n)7Be neutron sources have been used for decades in nuclear physics research, stellar nucleosynthesis research and neutron therapy research. In this work, the neutron characterization including neutron yield, spectra, and angular distribution for D-T and p-7Li sources have been studied with our new binary collision approximation (BCA) based direct collision coupling method. Distinguished from the traditional path integration method for getting the neutron weight, the new model establishes a relationship between the scattering cross section and the impact parameter, which allows the secondary neutron generation carrying out jointly with ions BCA tracking. The experimental measurements of neutron characterizations have been employed for these two reactions, and the new algorithm is validated.

Wang, Guan-bo; Yang, Xin; Qian, Da-zhi; Li, Run-dong; Tang, Bin

2014-09-01

278

Tomsk Polytechnic University cyclotron as a source for neutron based cancer treatment  

SciTech Connect

In this paper we present our cyclotron based neutron source with average energy 6.3 MeV generated during the 13.6 MeV deuterons interactions with beryllium target, neutron field dosimetry, and dosimetry of attendant gamma fields. We also present application of our neutron source for cancer treatment.

Lisin, V. A. [Cancer Research Institute, 5 Kooperativny St., Tomsk 634050 (Russian Federation) [Cancer Research Institute, 5 Kooperativny St., Tomsk 634050 (Russian Federation); Tomsk Polytechnic University, 30 Lenina av., Tomsk 634050 (Russian Federation); Bogdanov, A. V.; Golovkov, V. M.; Sukhikh, L. G.; Verigin, D. A., E-mail: verigin@tpu.ru [Tomsk Polytechnic University, 30 Lenina av., Tomsk 634050 (Russian Federation); Musabaeva, L. I. [Cancer Research Institute, 5 Kooperativny St., Tomsk 634050 (Russian Federation)] [Cancer Research Institute, 5 Kooperativny St., Tomsk 634050 (Russian Federation)

2014-02-15

279

Tomsk Polytechnic University cyclotron as a source for neutron based cancer treatment.  

PubMed

In this paper we present our cyclotron based neutron source with average energy 6.3 MeV generated during the 13.6 MeV deuterons interactions with beryllium target, neutron field dosimetry, and dosimetry of attendant gamma fields. We also present application of our neutron source for cancer treatment. PMID:24593651

Lisin, V A; Bogdanov, A V; Golovkov, V M; Musabaeva, L I; Sukhikh, L G; Verigin, D A

2014-02-01

280

DESIGN OPTIMIZATION AND THE PATH TOWARD SA2M W SPALLATION NEUTRON SOURCE  

Microsoft Academic Search

The Spallation Neutron Source (SNS) is designed to ul- timately reach an average proton beam power of 2 MW for pulsed neutron production. The SNS physics groups an- alyze the machine performance within the hardware con- straints, optimize the accelerator design, and establish the best path towards a 2 MW and higher spallation neutron source.

J. Wei; M. Blaskiewicz; N. Catalan-Lasheras; D. Davino; A. Fedotov; Y. Y. Lee; N. Malitsky; Y. Papaphilippou; D. Raparia; A. Shishlo; N. Tsoupas; W. Weng; S. Y. Zhang; R. Keller; J. Staples; J. Stovall; J. Billen; S. Kurennoy; S. Nath; H. Takeda; L. Young; R. Sundelin; A. Aleksandrov; Y. Cho; P. Chu; S. Cousineau; V. Danilov; M. Doleans; J. Galambos; J. Holmes; N. Holtkamp; S. Kim; R. Kustom; D. Jeon; E. Tanke; W. Wan

2001-01-01

281

Design optimization and the path towards a 2 MW Spallation Neutron Source  

Microsoft Academic Search

The Spallation Neutron Source (SNS) is designed to ultimately reach an average proton beam power of 2 MW for pulsed neutron production. The SNS physics groups analyze the machine performance within the hardware constraints, optimize the accelerator design, and establish the best path towards a 2 MW and higher Spallation Neutron Source

J. Wei; M. Blaskiewicz; N. Catalan-Lasheras; D. Davino; A. Fedotov; Y. Y. Lee; N. Malitsky; Y. Papaphilippou; D. Raparia; A. Shishlo; N. Tsoupas; W. Weng; S. Y. Zhang; R. Keller; J. Staples; J. Stovall; J. Billen; S. Kurennoy; S. Nath; H. Takeda; L. Young; R. Sundelin; A. Aleksandrov; Y. Cho; P. Chu; S. Cousineau; V. Danilov; M. Doleans; J. Galambos; J. Holmes; N. Holtkamp; S. Kim; R. Kustom; D. Jeon; E. Tanke; W. Wan

2001-01-01

282

Experimental tests with MISANS (Modulated Intensity Small Angle Neutron Scattering) at IPNS (Intense Pulsed Neutron Source).  

SciTech Connect

In this paper we describe the latest tests of the MISANS spectrometer at the IPNS in Argonne, USA. At this stage the time resolution and more importantly the contrast of the modulation at the detector is very low, nevertheless it was possible to perform a MISANS-measurement and test some features typical for a pulsed neutron source. The MISANS technique has a huge potential to improve its contrast and resolution towards a high resolution spin echo spectrometer.

Bleuel, M.; Gahler, R.; Lang, E.; Lal, J.; Inst. Laue Langevin

2009-01-01

283

Spallation neutron source saddle antenna H{sup -} ion source project  

SciTech Connect

In this project we are developing an H{sup -} source which will synthesize the most important developments in the field of negative ion sources to provide high current, high brightness, good lifetime, high reliability, and high power efficiency. We describe two planned modifications to the present spallation neutron source external antenna source in order to increase the plasma density near the output aperture: (1) replacing the present 2 MHz plasma-forming solenoid antenna with a 13 MHz saddle-type antenna and (2) replacing the permanent multicusp magnetic system with a weaker electromagnet.

Dudnikov, Vadim; Johnson, Rolland P. [Muons, Inc., Batavia, Illinois 60510 (United States); Dudnikova, Galina [University of Maryland, College Park, Maryland 20742 (United States); Stockli, Martin; Welton, Robert [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2010-02-15

284

Advanced Neutron Source Reactor thermal analysis of fuel plate defects  

SciTech Connect

The Advanced Neutron Source Reactor (ANSR) is a research reactor designed to provide the highest continuous neutron beam intensity of any reactor in the world. The present technology for determining safe operations were developed for the High Flux Isotope Reactor (HFIR). These techniques are conservative and provide confidence in the safe operation of HFIR. However, the more intense requirements of ANSR necessitate the development of more accurate, but still conservative, techniques. This report details the development of a Local Analysis Technique (LAT) that provides an appropriate approach. Application of the LAT to two ANSR core designs are presented. New theories of the thermal and nuclear behavior of the U{sub 3}Si{sub 2} fuel are utilized. The implications of lower fuel enrichment and of modifying the inspection procedures are also discussed. Development of the computer codes that enable the automate execution of the LAT is included.

Giles, G.E.

1995-08-01

285

Inertial electrostatic confinement fusion neutron source R & D and issues  

SciTech Connect

An inertial electrostatic confinement (IEC) fusion is the scheme of injecting the ions and electrons toward the spherical center, trapping both species in the electrostatic self-field and giving rise to fusion reactions in the dense core. An IEC is expected to have wide application from a small neutron source to a D-{sup 3}He fusion reactor. Hirsch reported 10{sup 9} n/s deuterium-tritium (D-T) neutron production in the device equipped with ion guns. Recently, Gu et al. measured 10{sup 6} n/s using a D{sub 2} gas discharge between the spherical wire cathode and the anode vacuum vessel, where the applied voltage is 60 kV and the current is 15 mA. We have also obtained similar neutron production at a lower voltage, {approximately}45 kV in a single-grid IEC device. Fusion reaction rates obtained by IEC experiments so far cannot be explained by a model of a simple potential well structure because the electrical potential peaked at the center prevents making a dense core. Hirsch proposed a multiwell structure called {open_quotes}poissors{close_quotes} to explain the experiments. It is generally believed that there may be some correlation between the potential well structure and the neutron production rate. The scaling of neutron production on the injected ion current is a most important aspect of the problem for the prospect of utilizing IEC for fusion energy. The potential structure and its behavior are keys to the physics in understanding the principle of an IEC.

Ohnishi, Masami; Yamamoto, Yasushi; Hasegawa, Mitsunori [Kyoto Univ. (Japan)] [and others

1997-12-01

286

General Electric PETtrace cyclotron as a neutron source for boron neutron capture therapy  

NASA Astrophysics Data System (ADS)

This research investigates the use of a PETtrace cyclotron produced by General Electric (GE) as a neutron source for boron neutron capture therapy (BNCT). The GE PETtrace was chosen for this investigation because this type of cyclotron is popular among nuclear pharmacies and clinics in many countries; it is compact and reliable; it produces protons with energies high enough to produce neutrons with appropriate energy and fluence rate for BNCT and it does not require significant changes in design to provide neutrons. In particular, the standard PETtrace 18O target is considered. The cyclotron efficiency may be significantly increased if unused neutrons produced during radioisotopes production could be utilized for other medical modalities such as BNCT at the same time. The resulting dose from the radiation emitted from the target is evaluated using the Monte Carlo radiation transport code MCNP at several depths in a brain phantom for different scattering geometries. Four different moderating materials of various thicknesses were considered: light water, carbon, heavy water, arid Fluental(TM). The fluence rate tally was used to calculate photon and neutron dose, by applying fluence rate-to-dose conversion factors. Fifteen different geometries were considered and a 30-cm thick heavy water moderator was chosen as the most suitable for BNCT with the GE PETtrace cyclotron. According to the Brookhaven Medical Research Reactor (BMRR) protocol, the maximum dose to the normal brain is set to 12.5 RBEGy, which for the conditions of using a heavy water moderator, assuming a 60 muA beam current, would be reached with a treatment time of 258 min. Results showed that using a PETtrace cyclotron in this configuration provides a therapeutic ratio of about 2.4 for depths up to 4 cm inside a brain phantom. Further increase of beam current proposed by GE should significantly improve the beam quality or the treatment time and allow treating tumors at greater depths.

Bosko, Andrey

287

Novel Large Area High Resolution Neutron Detector for the Spallation Neutron Source  

SciTech Connect

Neutron scattering is a powerful technique that is critically important for materials science and structural biology applications. The knowledge gained from past developments has resulted in far-reaching advances in engineering, pharmaceutical and biotechnology industries, to name a few. New facilities for neutron generation at much higher flux, such as the SNS at Oak Ridge, TN, will greatly enhance the capabilities of neutron scattering, with benefits that extend to many fields and include, for example, development of improved drug therapies and materials that are stronger, longer-lasting, and more impact-resistant. In order to fully realize this enhanced potential, however, higher neutron rates must be met with improved detection capabilities, particularly higher count rate capability in large size detectors, while maintaining practicality. We have developed a neutron detector with the technical and economic advantages to accomplish this goal. This new detector has a large sensitive area, offers 3D spatial resolution, high sensitivity and high count rate capability, and it is economical and practical to produce. The proposed detector technology is based on B-10 thin film conversion of neutrons in long straw-like gas detectors. A stack of many such detectors, each 1 meter in length, and 4 mm in diameter, has a stopping power that exceeds that of He-3 gas, contained at practical pressures within an area detector. With simple electronic readout methods, straw detector arrays can provide spatial resolution of 4 mm FWHM or better, and since an array detector of such form consists of several thousand individual elements per square meter, count rates in a 1 m^2 detector can reach 2?10^7 cps. Moreover, each individual event can be timetagged with a time resolution of less than 0.1 ?sec, allowing accurate identification of neutron energy by time of flight. Considering basic elemental cost, this novel neutron imaging detector can be commercially produced economically, probably at a small fraction of the cost of He-3 detectors. In addition to neutron scattering science, the fully developed base technology can be used as a rugged, low-cost neutron detector in area monitoring and surveying. Radiation monitors are used in a number of other settings for occupational and environmental radiation safety. Such a detector can also be used in environmental monitoring and remote nuclear power plant monitoring. For example, the Department of Energy could use it to characterize nuclear waste dumps, coordinate clean-up efforts, and assess the radioactive contaminants in the air and water. Radiation monitors can be used to monitor the age and component breakdown of nuclear warheads and to distinguish between weapons and reactor grade plutonium. The UN's International Atomic Energy Agency (IAEA) uses radiation monitors for treaty verification, remote monitoring, and enforcing the non-proliferation of nuclear weapons. As part of treaty verification, monitors can be used to certify the contents of containers during inspections. They could be used for portal monitoring to secure border checkpoints, sea ports, air cargo centers, public parks, sporting venues, and key government buildings. Currently, only 2% of all sea cargo shipped is inspected for radiation sources. In addition, merely the presence of radiation is detected and nothing is known about the radioactive source until further testing. The utilization of radiation monitors with neutron sensitivity and capability of operation in hostile port environments would increase the capacity and effectiveness of the radioactive scanning processes.

Lacy, Jeffrey L

2009-05-22

288

Neutron interrogation to identify chemical elements with an ion-tube neutron source (INS)  

SciTech Connect

A non-destructive analysis technique using a portable, electric ion-tube neutron source (INS) and gamma ray detector has been used to identify the key constituent elements in a number of sealed munitions, and from the elemental makeup, infer the types of agent within each. The high energy (14 MeV) and pulsed character of the neutron flux from an INS provide a method of measuring, quantitatively, the oxygen, carbon, and fluorine content of materials in closed containers, as well as the other constituents that can be measured with low-energy neutron probes. The broad range of elements that can be quantitatively measured with INS-based instruments provides a capability of verifying common munition fills; it provides the greatest specificity of any portable neutron-based technique for determining the full matrix of chemical elements in completely unrestricted sample scenarios. The specific capability of quantifying the carbon and oxygen content of materials should lead to a fast screening technique which, can discriminate very quickly between high-explosive and chemical agent-filled containers.

Alvarez, R.A.; Dougan, A.D.; Rowland, M.R.; Wang, T.F.

1994-04-07

289

Post-irradiation examination of the Spallation Neutron Source target module  

Microsoft Academic Search

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is an accelerator-based pulsed neutron source that produces high-energy spallation neutrons by bombarding liquid mercury flowing through a stainless steel target vessel. During operation the proton beam and spallation neutrons produce radiation damage in the AISI 316L austenitic stainless steel target vessel and water-cooled shroud. The beam pulses also cause

David A McClintock; Phillip D Ferguson; Louis K Mansur

2010-01-01

290

A compact neutron generator using a field ionization source  

SciTech Connect

Field ionization as a means to create ions for compact and rugged neutron sources is pursued. Arrays of carbon nano-#12;bers promise the high #12;eld-enhancement factors required for efficient field ionization. We report on the fabrication of arrays of #12;field emitters with a density up to 10{sup 6} tips/cm{sup 2} and measure their performance characteristics using electron field emission. The critical issue of uniformity is discussed, as are efforts towards coating the nano-fibers to enhance their lifetime and surface properties.

Persaud, Arun; Waldmann, Ole; Kapadia, Rehan; Takei, Kuniharu; Javey, Ali; Schenkel, Thomas

2011-10-31

291

A compact neutron generator using a field ionization source.  

PubMed

Field ionization as a means to create ions for compact and rugged neutron sources is pursued. Arrays of carbon nano-fibers promise the high field-enhancement factors required for efficient field ionization. We report on the fabrication of arrays of field emitters with a density up to 10(6)?tips?cm(2) and measure their performance characteristics using electron field emission. The critical issue of uniformity is discussed, as are efforts towards coating the nano-fibers to enhance their lifetime and surface properties. PMID:22380291

Persaud, Arun; Waldmann, Ole; Kapadia, Rehan; Takei, Kuniharu; Javey, Ali; Schenkel, Thomas

2012-02-01

292

Physics design of the National Spallation Neutron Source linac  

SciTech Connect

The National Spallation Neutron Source (NSNS) requires a linac that accelerates a H{sup {minus}} beam to 1.0 GeV. The linac starts with a radio-frequency quadrupole (RFQ) accelerator, which is followed by a drift-tube linac (DTL), a coupled-cavity drift-tube linac (CCDTL), and a conventional coupled-cavity linac (CCL). In this paper, the authors focus on the DTL, CCDTL, and CCL parts of the accelerator. They discuss the linac design parameters and beam dynamics issues. The design rationale of no separate matching sections between different accelerating sections maintains the current independence of beam behavior.

Takeda, H.; Billen, J.H.; Nath, S.

1997-10-01

293

Advanced Neutron Source (ANS) Project. Progress report FY 1993  

SciTech Connect

This report covers the progress made in 1993 in the following sections: (1) project management; (2) research and development; (3) design and (4) safety. The section on research and development covers the following: (1) reactor core development; (2) fuel development; (3) corrosion loop tests and analysis; (4) thermal-hydraulic loop tests; (5) reactor control and shutdown concepts; (6) critical and subcritical experiments; (7) material data, structure tests, and analysis; (8) cold source development; (9) beam tube, guide, and instrument development; (10) neutron transport and shielding; (11) I and C research and development; and (12) facility concepts.

Campbell, J.H. [ed.; Selby, D.L.; Harrington, R.M. [Oak Ridge National Lab., TN (United States); Thompson, P.B. [Martin Marietta Energy Systems, Inc., Oak Ridge, TN (United States). Engineering Div.

1994-01-01

294

A new fuel loading design for the Advanced Neutron Source  

SciTech Connect

A new fuel loading design has been developed for the Advanced Neutron Source Reactor. In this reactor the combination of a small core volume and high power results in a very high power density. Using a direct optimization procedure the thermal-hydraulic margins for oxide temperature drop, centerline temperature and incipient boiling (and thus critical heat flux) were maximized to increase the limiting thermal power from 298 MW to 346 MW compared to the previous fuel grading, while maintaining the desired peak reflector thermal flux.

Gehin, J.C.; Renier, J.P.; Worley, B.A.

1994-06-01

295

SPALLATION NEUTRON SOURCE RING-DESIGN AND CONSTRUCTION SUMMARY.  

SciTech Connect

After six years, the delivery of components for the Spallation Neutron Source (SNS) accumulator ring (AR) and the transport lines was completed in Spring 2005. Designed to deliver 1.5 MW beam power (1.5 x 10{sup 14} protons of 1 GeV kinetic energy at a repetition rate of 60 Hz), stringent measures were implemented in the fabrication, test, and assembly to ensure the quality of the accelerator systems. This paper summarizes the design, R&D, and construction of the ring and transport systems.

WEI,J.

2005-05-16

296

Creep analysis of fuel plates for the Advanced Neutron Source  

SciTech Connect

The reactor for the planned Advanced Neutron Source will use closely spaced arrays of fuel plates. The plates are thin and will have a core containing enriched uranium silicide fuel clad in aluminum. The heat load caused by the nuclear reactions within the fuel plates will be removed by flowing high-velocity heavy water through narrow channels between the plates. However, the plates will still be at elevated temperatures while in service, and the potential for excessive plate deformation because of creep must be considered. An analysis to include creep for deformation and stresses because of temperature over a given time span has been performed and is reported herein.

Swinson, W.F.; Yahr, G.T.

1994-11-01

297

Neutron source capability assessment for cumulative fission yields measurements  

SciTech Connect

A recent analysis of high-quality cumulative fission yields data for Pu-239 published in the peer-reviewed literature showed that the quoted experimental uncertainties do not allow a clear statement on how the fission yields vary as a function of energy. [Prussin2009] To make such a statement requires a set of experiments with well 'controlled' and understood sources of experimental errors to reduce uncertainties as low as possible, ideally in the 1 to 2% range. The Inter Laboratory Working Group (ILWOG) determined that Directed Stockpile Work (DSW) would benefit from an experimental program with the stated goal to reduce the measurement uncertainties significantly in order to make a definitive statement of the relationship of energy dependence to the cumulative fission yields. Following recent discussions between Lawrence Livermore National Laboratory (LLNL) and Los Alamos National Laboratory (LANL), there is a renewed interest in developing a concerted experimental program to measure fission yields in a neutron energy range from thermal energy (0.025 eV) to 14 MeV with an emphasis on discrete energies from 0.5 to 4 MeV. Ideally, fission yields would be measured at single energies, however, in practice there are only 'quasi-monoenergetic' neutrons sources of finite width. This report outlines a capability assessment as of June 2011 of available neutron sources that could be used as part of a concerted experimental program to measure cumulative fission yields. In a framework of international collaborations, capabilities available in the United States, at the Atomic Weapons Establishment (AWE) in the United Kingdom and at the Commissariat Energie Atomique (CEA) in France are listed. There is a need to develop an experimental program that will reduce the measurement uncertainties significantly in order to make a definitive statement of the relationship of energy dependence to the cumulative fission yields. Fission and monoenergetic neutron sources are available that could support these fission yield experiments in the US, as well as at AWE and CEA. Considerations that will impact the final choice of experimental venues are: (1) Availability during the timeframe of interest; (2) Ability to accommodate special nuclear materials; (3) Cost; (4) Availability of counting facilities; and (5) Expected experimental uncertainties.

Descalle, M A; Dekin, W; Kenneally, J

2011-04-06

298

Lithium target for accelerator based BNCT neutron source: Influence by the proton irradiation on lithium  

NASA Astrophysics Data System (ADS)

The neutron source for Boron Neutron Capture Therapy (BNCT) is in the transition stage from nuclear reactor to accelerator based neutron source. Generation of low energy neutron can be achieved by 7Li (p, n) 7Be reaction using accelerator based neutron source. Development of small-scale and safe neutron source is within reach. The melting point of lithium that is used for the target is low, and durability is questioned for an extended use at a high current proton beam. In order to test its durability, we have irradiated lithium with proton beam at the same level as the actual current density, and found no deterioration after 3 hours of continuous irradiation. As a result, it is suggested that lithium target can withstand proton irradiation at high current, confirming suitability as accelerator based neutron source for BNCT.

Fujii, R.; Imahori, Y.; Nakakmura, M.; Takada, M.; Kamada, S.; Hamano, T.; Hoshi, M.; Sato, H.; Itami, J.; Abe, Y.; Fuse, M.

2012-12-01

299

Generalization of the analytical solution of neutron point kinetics equations with time-dependent external source  

NASA Astrophysics Data System (ADS)

Point reactor kinetics equations with one group of delayed neutrons in the presence of the time-dependent external neutron source are solved analytically during the start-up of a nuclear reactor. Our model incorporates the random nature of the source and linear reactivity variation. We establish a general relationship between the expectation values of source intensity and the expectation values of neutron density of the sub-critical reactor by ignoring the term of the second derivative for neutron density in neutron point kinetics equations. The results of the analytical solution are in good agreement with the results obtained with numerical solution.

Seidi, M.; Behnia, S.; Khodabakhsh, R.

2014-09-01

300

Study on High Speed Lithium Jet For Neutron Source of Boron Neutron Capture Therapy (BNCT)  

NASA Astrophysics Data System (ADS)

The feasibility study of a liquid lithium type proton beam target was performed for the neutron source of the boron neutron capture therapy (BNCT). As the candidates of the liquid lithium target, a thin sheet jet and a thin film flow on a concave wall were chosen, and a lithium flow experiment was conducted to investigate the hydrodynamic stability of the targets. The surfaces of the jets and film flows with a thickness of 0.5 mm and a width of 50 mm were observed by means of photography. It has been found that a stable sheet jet and a stable film flow on a concave wall can be formed up to certain velocities by using a straight nozzle and a curved nozzle with the concave wall, respectively.

Takahashi, Minoru; Kobayashi, Tooru; Zhang, Mingguang; Mk, Michael; tefanica, Jir; Dostl, Vclav; Zhao, Wei

301

Detection of buried explosives using portable neutron sources with nanosecond timing.  

PubMed

Significant reduction of time needed to identify hidden explosives and other hazardous materials by the "neutron in, gamma out" method has been achieved by introducing timed (nanosecond) neutron sources-the so-called nanosecond neutron analysis technique. Prototype mobile device for explosives' detection based on a timed (nanosecond) isotopic (252)Cf neutron source has been created. The prototype is capable of identifying 400 g of hidden explosives in 10 min. Tests have been also made with a prototype device using timed (nanosecond) neutron source based on a portable D-T neutron generator with built-in segmented detector of accompanying alpha-particles. The presently achieved intensity of the neutron generator is 5x10(7)n/s into 4pi, with over 10(6) of these neutrons being correlated with alpha-particles detected by the built-in alpha-particle detector. Results of measurements with an anti-personnel landmine imitator are presented. PMID:15145438

Kuznetsov, A V; Evsenin, A V; Gorshkov, I Yu; Osetrov, O I; Vakhtin, D N

2004-07-01

302

Beam intensity increases at the intense pulsed neutron source accelerator  

SciTech Connect

The Intense Pulsed Neutron Source (IPNS) accelerator system has managed a 40% increase in time average beam current over the last two years. Currents of up to 15.6..mu..A (3.25 x 10/sup 12/ protons at 30 Hz) have been successfully accelerated and cleanly extracted. Our high current operation demands low loss beam handling to permit hands-on maintenance. Synchrotron beam handling efficiencies of 90% are routine. A new H/sup -/ ion source which was installed in March of 1983 offered the opportunity to get above 8 ..mu..A but an instability caused unacceptable losses when attempting to operate at 10 ..mu..A and above. Simple techniques to control the instabilities were introduced and have worked well. These techniques are discussed below. Other improvements in the regulation of various power supplies have provided greatly improved low energy orbit stability and contributed substantially to the increased beam current.

Potts, C.; Brumwell, F.; Norem, J.; Rauchas, A.; Stipp, V.; Volk, G.

1985-01-01

303

5 MW pulsed spallation neutron source, Preconceptual design study  

SciTech Connect

This report describes a self-consistent base line design for a 5 MW Pulsed Spallation Neutron Source (PSNS). It is intended to establish feasibility of design and as a basis for further expanded and detailed studies. It may also serve as a basis for establishing project cost (30% accuracy) in order to intercompare competing designs for a PSNS not only on the basis of technical feasibility and technical merit but also on the basis of projected total cost. The accelerator design considered here is based on the objective of a pulsed neutron source obtained by means of a pulsed proton beam with average beam power of 5 MW, in {approx} 1 {mu}sec pulses, operating at a repetition rate of 60 Hz. Two target stations are incorporated in the basic facility: one for operation at 10 Hz for long-wavelength instruments, and one operating at 50 Hz for instruments utilizing thermal neutrons. The design approach for the proton accelerator is to use a low energy linear accelerator (at 0.6 GeV), operating at 60 Hz, in tandem with two fast cycling booster synchrotrons (at 3.6 GeV), operating at 30 Hz. It is assumed here that considerations of cost and overall system reliability may favor the present design approach over the alternative approach pursued elsewhere, whereby use is made of a high energy linear accelerator in conjunction with a dc accumulation ring. With the knowledge that this alternative design is under active development, it was deliberately decided to favor here the low energy linac-fast cycling booster approach. Clearly, the present design, as developed here, must be carried to the full conceptual design stage in order to facilitate a meaningful technology and cost comparison with alternative designs.

Not Available

1994-06-01

304

Improvements to the internal and external antenna H(-) ion sources at the Spallation Neutron Source.  

PubMed

The Spallation Neutron Source (SNS), a large scale neutron production facility, routinely operates with 30-40 mA peak current in the linac. Recent measurements have shown that our RF-driven internal antenna, Cs-enhanced, multi-cusp ion sources injects ?55 mA of H(-) beam current (?1 ms, 60 Hz) at 65-kV into a Radio Frequency Quadrupole (RFQ) accelerator through a closely coupled electrostatic Low-Energy Beam Transport system. Over the last several years a decrease in RFQ transmission and issues with internal antennas has stimulated source development at the SNS both for the internal and external antenna ion sources. This report discusses progress in improving internal antenna reliability, H(-) yield improvements which resulted from modifications to the outlet aperture assembly (applicable to both internal and external antenna sources) and studies made of the long standing problem of beam persistence with the external antenna source. The current status of the external antenna ion source will also be presented. PMID:24593575

Welton, R F; Dudnikov, V G; Han, B X; Murray, S N; Pennisi, T R; Pillar, C; Santana, M; Stockli, M P; Turvey, M W

2014-02-01

305

Demonstration of a solid deuterium source of ultra-cold neutrons  

E-print Network

Ultra-cold neutrons (UCN), neutrons with energies low enough to be confined by the Fermi potential in material bottles, are playing an increasing role in measurements of fundamental properties of the neutron. The ability to manipulate UCN with material guides and bottles, magnetic fields, and gravity can lead to experiments with lower systematic errors than have been obtained in experiments with cold neutron beams. The UCN densities provided by existing reactor sources limit these experiments. The promise of much higher densities from solid deuterium sources has led to proposed facilities coupled to both reactor and spallation neutron sources. In this paper we report on the performance of a prototype spallation neutron-driven solid deuterium source. This source produced bottled UCN densities of 145 +/-7 UCN/cm3, about three times greater than the largest bottled UCN densities previously reported. These results indicate that a production UCN source with substantially higher densities should be possible.

A. Saunders; J. M. Anaya; T. J. Bowles; B. W. Filippone; P. Geltenbort; R. E. Hill; M. Hino; S. Hoedl; G. E. Hogan; T. M. Ito; K. W. Jones; T. Kawai; K. Kirch; S. K. Lamoreaux; C. -Y. Liu; M. Makela; L. J. Marek; J. W. Martin; C. L. Morris; R. N. Mortensen; A. Pichlmaier; S. J. Seestrom; A. Serebrov; D. Smith; W. Teasdale; B. Tipton; R. B. Vogelaar; A. R. Young; J. Yuan

2003-12-18

306

Modeling ion sources with application to neutron generation and surface treatment  

Microsoft Academic Search

We present simulation results of two ion sources: (i) a pulsed, cold cathode ion source used for generation of neutrons, and (ii) an anode layer ion source used for treatment of surfaces in industrial applications. We compare the simulation results with experiment: in case (i), we compare the neutron yield with measured yields, and in case (ii), we compare the

P. H. Stoltz

2008-01-01

307

The flow mechanism in the Chalk based on radio-isotope analyses of groundwater in the London Basin  

USGS Publications Warehouse

14C analyses of groundwaters from the Chalk of the London Basin are re-interpreted and the age of the groundwater is revised. Radio-isotope analyses are used to examine the flow mechanism in the aquifer. The evidence supports the view that a network of micro-fissures and larger intergranular pores in the matrix provides a significant part of the water pumped from Chalk wells and the major fissures distribute the water to the wells. Most of the matrix is fine-grained and contains a very old water. This diffuses into the micro-fissures and larger pores and is carried to the wells by the major fissures. ?? 1979.

Downing, R.A.; Pearson, F.J.; Smith, D.B.

1979-01-01

308

Validation of multigroup neutron cross sections for the Advanced Neutron Source against the FOEHN critical experimental measurements  

SciTech Connect

The FOEHN critical experiments were analyzed to validate the use of multigroup cross sections in the design of the Advanced Neutron Source. Eleven critical configurations were evaluated using the KENO, DORT, and VENTURE neutronics codes. Eigenvalue and power density profiles were computed and show very good agreement with measured values.

Smith, L.A.; Gehin, J.C.; Worley, B.A.; Renier, J.P.

1994-04-01

309

Assessment of restrictions imposed by neutron irradiation on the workability of a copper conductor in volumetric neutron source coils  

Microsoft Academic Search

The paper presents the results of the analysis of the irradiation conditions and the quantitative estimation of factors that control the lifetime of copper alloys as materials for a conductor in volumetric neutron source coils, as well the results of the analysis of the effect of neutron irradiation at Tirr?=?100C on the mechanical properties and electrical conductivity of copper alloys

S. A. Fabritsiev; E. A. Azizov; A. B. Mineev; V. A. Korotkov

2005-01-01

310

Characteristics comparison between a cyclotron-based neutron source and KUR-HWNIF for boron neutron capture therapy  

Microsoft Academic Search

At Kyoto University Research Reactor Institute (KURRI), 275 clinical trials of boron neutron capture therapy (BNCT) have been performed as of March 2006, and the effectiveness of BNCT has been revealed. In order to further develop BNCT, it is desirable to supply accelerator-based epithermal-neutron sources that can be installed near the hospital. We proposed the method of filtering and moderating

H. Tanaka; Y. Sakurai; M. Suzuki; S. Masunaga; Y. Kinashi; G. Kashino; Y. Liu; T. Mitsumoto; S. Yajima; H. Tsutsui; A. Maruhashi; K. Ono

2009-01-01

311

The Advanced Neutron Source (ANS) project: A world-class research reactor facility  

Microsoft Academic Search

This paper provides an overview of the Advanced Neutron Source (ANS), a new research facility being designed at Oak Ridge National Laboratory. The facility is based on a 330 MW, heavy-water cooled and reflected reactor as the neutron source, with a thermal neutron flux of about 7.510¹⁹m⁻²·sec⁻¹. Within the reflector region will be one hot source which will serve 2

P. B. Thompson; W. E. Meek

1993-01-01

312

NEUTRON ACTIVATION ANALYSIS APPLICATIONS AT THE SAVANNAH RIVER SITE USING AN ISOTOPIC NEUTRON SOURCE  

SciTech Connect

NAA using {sup 252}Cf is used to address important areas of applied interest at SRS. Sensitivity needs for many of the applications are not severe; analyses are accomplished using a 21 mg {sup 252}Cf NAA facility. Because NAA allows analysis of bulk samples, it offers strong advantages for samples in difficult-to-digest matrices when its sensitivity is sufficient. Following radiochemical separation with stable carrier addition, chemical yields for a number methods are determined by neutron activation of the stable carrier. In some of the cases where no suitable stable carriers exist, the source has been used to generate radioactive tracers to yield separations.

Diprete, D; C Diprete, C; Raymond Sigg, R

2006-08-14

313

Neutron resonance transmission spectroscopy with high spatial and energy resolution at the J-PARC pulsed neutron source  

NASA Astrophysics Data System (ADS)

The sharp variation of neutron attenuation at certain energies specific to particular nuclides (the lower range being from ~1 eV up to ~1 keV), can be exploited for the remote mapping of element and/or isotope distributions, as well as temperature probing, within relatively thick samples. Intense pulsed neutron beam-lines at spallation sources combined with a high spatial, high-timing resolution neutron counting detector, provide a unique opportunity to measure neutron transmission spectra through the time-of-flight technique. We present the results of experiments where spatially resolved neutron resonances were measured, at energies up to 50 keV. These experiments were performed with the intense flux low background NOBORU neutron beamline at the J-PARC neutron source and the high timing resolution (~20 ns at epithermal neutron energies) and spatial resolution (~55 ?m) neutron counting detector using microchannel plates coupled to a Timepix electronic readout. Simultaneous element-specific imaging was carried out for several materials, at a spatial resolution of ~150 ?m. The high timing resolution of our detector combined with the low background beamline, also enabled characterization of the neutron pulse itself - specifically its pulse width, which varies with neutron energy. The results of our measurements are in good agreement with the predicted results for the double pulse structure of the J-PARC facility, which provides two 100 ns-wide proton pulses separated by 600 ns, broadened by the neutron energy moderation process. Thermal neutron radiography can be conducted simultaneously with resonance transmission spectroscopy, and can reveal the internal structure of the samples. The transmission spectra measured in our experiments demonstrate the feasibility of mapping elemental distributions using this non-destructive technique, for those elements (and in certain cases, specific isotopes), which have resonance energies below a few keV, and with lower resolution for elements with relatively high resonance energies in the 1-30 keV range.

Tremsin, A. S.; Shinohara, T.; Kai, T.; Ooi, M.; Kamiyama, T.; Kiyanagi, Y.; Shiota, Y.; McPhate, J. B.; Vallerga, J. V.; Siegmund, O. H. W.; Feller, W. B.

2014-05-01

314

A Project of Boron Neutron Capture Therapy System based on a Proton Linac Neutron Source  

NASA Astrophysics Data System (ADS)

At present, the clinical trials of Boron Neutron Capture Therapy (BNCT) are being performed at research reactor facilities. However, an accelerator based BNCT has a merit that it can be built in a hospital. So, we just launched a development project for the BNCT based on an accelerator in order to establish and to spread the BNCT as an effective therapy in the near future. In the project, a compact proton linac installed in a hospital will be applied as a neutron source, and energy of the proton beam is planned to be less than about 10 MeV to reduce the radioactivity. The BNCT requires epithermal neutron beam with an intensity of around 1x109 (n/cm2/sec) to deliver the therapeutic dose to a deeper region in a body and to complete the irradiation within an hour. From this condition, the current of the proton beam required is estimated to be a few mA on average. Enormous heat deposition in the target is a big issue. We are aiming at total optimization of the accelerator based BNCT from the linac to the irradiation position. Here, the outline of the project is introduced and the moderator design is presented.

Kiyanagi, Yoshikai; Asano, Kenji; Arakawa, Akihiro; Fukuchi, Shin; Hiraga, Fujio; Kimura, Kenju; Kobayashi, Hitoshi; Kubota, Michio; Kumada, Hiroaki; Matsumoto, Hiroshi; Matsumoto, Akira; Sakae, Takeji; Saitoh, Kimiaki; Shibata, Tokushi; Yoshioka, Masakazu

315

Pre-conceptual design and preliminary neutronic analysis of the proposed National Spallation Neutron Source (NSNS)  

SciTech Connect

The Department of Energy (DOE) has initiated a pre-conceptual design study for the National Spallation Neutron Source (NSNS) and given preliminary approval for the proposed facility to be built at Oak Ridge National Laboratory (ORNL). The pre-conceptual design of the NSNS initially consists of an accelerator system capable of delivering a 1 to 2 GeV proton beam with 1 MW of beam power in an approximate 0.5 {micro}s pulse at a 60 Hz frequency onto a single target station. The NSNS will be upgradable to a significantly higher power level with two target stations (a 60 Hz station and a 10 Hz station). There are many possible layouts and designs for the NSNS target stations. This paper gives a brief overview of the proposed NSNS with respect to the target station, as well as the general philosophy adopted for the neutronic design of the NSNS target stations. A reference design is presented, and some preliminary neutronic results for the NSNS are briefly discussed.

Johnson, J.O.; Barnes, J.M.; Charlton, L.A. [Oak Ridge National Lab., TN (United States). Computational Physics and Engineering Div.

1997-03-01

316

Characteristics comparison between a cyclotron-based neutron source and KUR-HWNIF for boron neutron capture therapy  

NASA Astrophysics Data System (ADS)

At Kyoto University Research Reactor Institute (KURRI), 275 clinical trials of boron neutron capture therapy (BNCT) have been performed as of March 2006, and the effectiveness of BNCT has been revealed. In order to further develop BNCT, it is desirable to supply accelerator-based epithermal-neutron sources that can be installed near the hospital. We proposed the method of filtering and moderating fast neutrons, which are emitted from the reaction between a beryllium target and 30-MeV protons accelerated by a cyclotron accelerator, using an optimum moderator system composed of iron, lead, aluminum and calcium fluoride. At present, an epithermal-neutron source is under construction from June 2008. This system consists of a cyclotron accelerator, beam transport system, neutron-yielding target, filter, moderator and irradiation bed. In this article, an overview of this system and the properties of the treatment neutron beam optimized by the MCNPX Monte Carlo neutron transport code are presented. The distribution of biological effect weighted dose in a head phantom compared with that of Kyoto University Research Reactor (KUR) is shown. It is confirmed that for the accelerator, the biological effect weighted dose for a deeply situated tumor in the phantom is 18% larger than that for KUR, when the limit dose of the normal brain is 10 Gy-eq. The therapeutic time of the cyclotron-based neutron sources are nearly one-quarter of that of KUR. The cyclotron-based epithermal-neutron source is a promising alternative to reactor-based neutron sources for treatments by BNCT.

Tanaka, H.; Sakurai, Y.; Suzuki, M.; Masunaga, S.; Kinashi, Y.; Kashino, G.; Liu, Y.; Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Maruhashi, A.; Ono, K.

2009-06-01

317

Proposal for a New Integrated Circuit and Electronics Neutron Experiment Source at Oak Ridge National Laboratory  

SciTech Connect

Government and customer specifications increasingly require assessments of the single event effects probability in electronics from atmospheric neutrons. The accelerator that best simulates this neutron spectrum is the WNR facility (Los Alamos), but it is underfunded and oversubscribed for present and future needs. A new beam-line is proposed at the Oak Ridge National Laboratory, as part of the Spallation Neutron Source (SNS).

Ferguson, Phillip D [ORNL

2009-01-01

318

Study on an inertial electrostatic confinement fusion as a portable neutron source  

Microsoft Academic Search

The scaling of neutron generation versus ion current is important in evaluating the prospect of an inertial electrostatic confinement (IEC) as a neutron source. In this paper, the scaling of neutron generation versus ion current, I, based on the results of both the experiments and the numerical simulations is discussed. The experiments shows the scaling of I2, while the numerical

Masami Ohnishi; Yasushi Yamamoto; Mitsunori Hasegawa; Kiyoshi Yoshikawa; George H. Miley

1998-01-01

319

Calculations of anisotropy factors for radionuclide neutron sources due to scattering from source encapsulation and support structures.  

PubMed

A model has been developed for calculating the angular neutron fluence distributions for radionuclide neutron sources that are heavily encapsulated or surrounded by source support structures as a source holder and a source movement system. These structures may cause an anisotropic neutron fluence distribution. This should be taken into account in the neutron-measuring instruments calibration procedure. The calculations were made for two types of widely used neutron sources, (241)Am-Be and (252)Cf, by combining an in-house code simulating the (9)Be(alpha,n) reactions and the Monte Carlo code MCNP-4C. As a result, anisotropy factors in the direction perpendicular to the source capsule axis for bare neutron sources were evaluated to be 1.012, 1.030 and 1.039 for (252)Cf in a standard Amersham X1 capsule, (241)Am-Be in a X3 capsule and (241)Am-Be in a X4 capsule, respectively. These values are in reasonable agreement with the published data. If the support structures are included in the MCNP simulation, the anisotropy factors for these neutron sources increase by approximately 10%. PMID:17575299

Tsujimura, N; Yoshida, T; Momose, T

2007-01-01

320

On replacing Am-Be neutron sources in compensated porosity logging tools.  

PubMed

Authors explored the direct replacement of Am-Be neutron sources in neutron porosity logging tools through Monte Carlo simulations using MCNP5. (252)Cf and electronic accelerator neutron sources based on the Deuterium-Tritium fusion reaction were considered. Between the sources, a tradeoff was noted between sensitivity to the presence of hydrogen and uncertainty due to counting statistics. It was concluded that both replacement sources as well as accelerator sources based on the Deuterium-Deuterium fusion reaction warrant further consideration as porosity log sources. PMID:20047837

Peeples, Cody R; Mickael, Medhat; Gardner, Robin P

2010-01-01

321

Materials compatibility studies for the Spallation Neutron Source  

SciTech Connect

The Spallation Neutron Source (SNS) is a high power facility for producing neutrons that utilizes flowing liquid mercury inside an austenitic stainless steel container as the target for a 1.0 GeV proton beam. Type 316 SS has been selected as the container material for the mercury and consequences of exposure of 316 SS to radiation, thermal shock, thermal stress, cavitation and hot, flowing mercury are all being addressed by R and D programs. In addition, corrosion studies also include evaluation of Inconel 718 because it has been successfully used in previous spallation neutron systems as a window material. Two types of compatibility issues relative to 316 SS/mercury and Inconel 718/mercury are being examined: (1) liquid metal embrittlement (LME) and (2) temperature gradient mass transfer. Studies have shown that mercury does not easily wet type 316 SS below 275 C. In the LME experiments, attempts were made to promote wetting of the steel by mercury either by adding gallium to the mercury or coating the specimen with a tin-silver solder that the mercury easily wets. The latter proved more reliable in establishing wetting, but there was no evidence of LME in any of the constant extension rate tensile tests either at 23 or 100 C. Inconel 718 also showed no change in room temperature properties when tested in mercury or mercury-gallium. However, there was evidence that the fracture was less ductile. Preliminary evaluation of mass transfer of either type 316 SS or Inconel 718 in mercury or mercury-gallium at 350 C (maximum temperature) did not reveal significant effects. Two 5,000 h thermal convection loop tests of type 316 SS are in progress, with specimens in both hot and cold test regions, at 300 and 240 C, respectively.

DiStefano, J.R.; Pawel, S.J.; Manneschmidt, E.T.

1998-11-01

322

Measurement of the spectral fluence rate of reference neutron sources with a liquid scintillation detector.  

PubMed

Reference neutron sources such as (241)AmBe(alpha,n) and (252)Cf are commonly used to calibrate neutron detectors for radiation protection purposes. The calibration factors of these detectors depend on the spectral distribution of the neutron fluence from the source. Differences between the spectral fluence of the neutron source and the ISO-recommended reference spectra might be caused by the properties of the individual source. The spectral neutron fluence rates of different reference neutron sources used at PTB were measured with a liquid scintillation detector (NE213), using maximum entropy unfolding and a new, experimentally determined detector response matrix. The detector response matrix was determined by means of the time-of-flight technique at a pulsed neutron source with a broad energy distribution realised at the PTB accelerator facility. The results of the measurements of the reference sources are compared with the ISO-recommended reference spectra. For the PTB (241)AmBe(alpha,n) reference source, the spectral neutron fluence was determined by means of a high-resolution (3)He semiconductor sandwich spectrometer in 1982. These measurements were the basis for the ISO recommendations. The current measurements confirm the high-energy part (E(n) > 2 MeV) of this spectrum and demonstrate the suitability of this new method for high-resolution spectrometry of broad neutron spectra. PMID:17553863

Zimbal, A

2007-01-01

323

Optimizing Laser-accelerated Ion Beams for a Collimated Neutron Source  

SciTech Connect

High-flux neutrons for imaging and materials analysis applications have typically been provided by accelerator- and reactor-based neutron sources. A novel approach is to use ultraintense (>1018W/cm2) lasers to generate picosecond, collimated neutrons from a dual target configuration. In this article, the production capabilities of present and upcoming laser facilities are estimated while independently maximizing neutron yields and minimizing beam divergence. A Monte-Carlo code calculates angular and energy distributions of neutrons generated by D-D fusion events occurring within a deuterated target for a given incident beam of D+ ions. Tailoring of the incident distribution via laser parameters and microlens focusing modifies the emerging neutrons. Projected neutron yields and distributions are compared to conventional sources, yielding comparable on-target fluxes per discharge, shorter time resolution, larger neutron energies and greater collimation.

C.L. Ellison and J. Fuchs

2010-09-23

324

Simulation of a D-T neutron source for neutron scattering experiments  

NASA Astrophysics Data System (ADS)

A new generation of high-yield fusion-based neutron generators is being developed at Lawrence Berkeley National Laboratory. Novel design features provide the potential for neutron yields as high as 10 14 n/s in a compact geometry. Such high neutron yields make the neutron generator applicable to the production of thermal or cold neutrons for neutron scattering experiments. This paper describes a scheme to simulate a neutron scattering setup and to estimate neutron flux and resolution with the particle transport code MCNP. For an estimated resolution of 1-4%, depending on the scattered angle and neutron energy, a thermal neutron flux at the sample position of 710 5 n/cm2 s has been estimated. Such a neutron generator is particularly suitable for cold neutron scattering experiments due to relatively longer flight times.

Lou, T. P.; Ludewigt, B. A.; Vujic, J. L.; Leung, K.-N.

2004-04-01

325

Advanced Neutron Source (ANS) Project progress report, FY 1994  

SciTech Connect

The President`s budget request for FY 1994 included a construction project for the Advanced Neutron Source (ANS). However, the budget that emerged from the Congress did not, and so activities during this reporting period were limited to continued research and development and to advanced conceptual design. A significant effort was devoted to a study, requested by the US Department of Energy (DOE) and led by Brookhaven National Laboratory, of the performance and cost impacts of reducing the uranium fuel enrichment below the baseline design value of 93%. The study also considered alternative core designs that might mitigate those impacts. The ANS Project proposed a modified core design, with three fuel elements instead of two, that would allow operation with only 50% enriched uranium and use existing fuel technology. The performance penalty would be 15--20% loss of thermal neutron flux; the flux would still just meet the minimum design requirement set by the user community. At the time of this writing, DOE has not established an enrichment level for ANS, but two advisory committees have recommended adopting the new core design, provided the minimum flux requirements are still met.

Campbell, J.H.; King-Jones, K.H. [eds.; Selby, D.L.; Harrington, R.M. [Oak Ridge National Lab., TN (United States); Thompson, P.B. [Martin Marietta Energy Systems, Inc., Oak Ridge, TN (United States). Central Engineering Services

1995-01-01

326

(252)Cf-source-driven neutron noise analysis method  

NASA Astrophysics Data System (ADS)

The Cf-252-source-driven neutron noise analysis method has been tested in a wide variety of experiments that have indicated the broad range of applicability of the method. The neutron multiplication factor k(sub eff) has been satisfactorily determined for a variety of materials including uranium metal, light water reactor fuel pins, fissile solutions, fuel plates in water, and interacting cylinders. For a uranyl nitrate solution tank which is typical of a fuel processing or reprocessing plant, the k(sub eff) values were satisfactorily determined for values between 0.92 and 0.5 using a simple point kinetics interpretation of the experimental data. The short measurement times, in several cases as low as 1 min, have shown that the development of this method can lead to a practical subcriticality monitor for many in-plant applications. The further development of the method will require experiments oriented toward particular applications including dynamic experiments and the development of theoretical methods to predict the experimental observables.

Mihalczo, J. T.; King, W. T.; Blakeman, E. D.

327

Quantifying time in sedimentary successions by radio-isotopic dating of ash beds  

NASA Astrophysics Data System (ADS)

Sedimentary rock sequences are an accurate record of geological, chemical and biological processes throughout the history of our planet. If we want to know more about the duration or the rates of some of these processes, we can apply methods of absolute age determination, i.e. of radio-isotopic dating. Data of highest precision and accuracy, and therefore of highest degree of confidence, are obtained by chemical abrasion, isotope-dilution, thermal ionization mass spectrometry (CA-ID-TIMS) 238U-206Pb dating techniques, applied to magmatic zircon from ash beds that are interbedded with the sediments. This techniques allows high-precision estimates of age at the 0.1% uncertainty for single analyses, and down to 0.03% uncertainty for groups of statistically equivalent 206Pb/238U dates. Such high precision is needed, since we would like the precision to be approximately equivalent or better than the (interpolated) duration of ammonoid zones in the Mesozoic (e.g., Ovtcharova et al. 2006), or to match short feedback rates of biological, climatic, or geochemical cycles after giant volcanic eruptions in large igneous provinces (LIP's), e.g., at the Permian/Triassic or the Triassic/Jurassic boundaries. We also wish to establish as precisely as possible temporal coincidence between the sedimentary record and short-lived volcanic events within the LIP's. Precision and accuracy of the U-Pb data has to be traceable and quantifiable in absolute terms, achieved by direct reference to the international kilogram, via an absolute calibration of the standard and isotopic tracer solutions. Only with a perfect control on precision and accuracy of radio-isotopic data, we can confidently determine whether two ages of geological events are really different, and avoid mistaking interlaboratory or interchronometer biases for age difference. The development of unprecedented precision of CA-ID-TIMS 238U-206Pb dates led to the recognition of protracted growth of zircon in a magmatic liquid (see, e.g., Schoene et al. 2012), which then becomes transferred into volcanic ashes as excess dispersion of 238U-206Pb dates (see, e.g., Guex et al. 2012). Zircon is crystallizing in the magmatic liquid shortly before the volcanic eruption; we therefore aim at finding the youngest zircon date or youngest statistically equivalent cluster of 238U-206Pb dates as an approximation of ash deposition (Wotzlaw et al. 2013). Time gaps between last zircon crystallization and eruption ("?t") may be as large as 100-200 ka, at the limits of analytical precision. Understanding the magmatic crystallization history of zircon is the fundamental background for interpreting ash bed dates in a sedimentary succession. Ash beds of different stratigraphic position and age my be generated within different magmatic systems, showing different crystallization histories. A sufficient number of samples (N) is therefore of paramount importance, not to lose the stratigraphic age control in a given section, and to be able to discard samples with large ?t - but, how large has to be "N"? In order to use the youngest zircon or zircons as an approximation of the age of eruption and ash deposition, we need to be sure that we have quantitatively solved the problem of post-crystallization lead loss - but, how can we be sure?! Ash bed zircons are prone to partial loss of radiogenic lead, because the ashes have been flushed by volcanic gases, as well as brines during sediment compaction. We therefore need to analyze a sufficient number of zircons (n) to be sure not to miss the youngest - but, how large has to be "n"? Analysis of trace elements or oxygen, hafnium isotopic compositions in dated zircon may sometimes help to distinguish zircon that is in equilibrium with the last magmatic liquid, from those that are recycled from earlier crystallization episodes, or to recognize zircon with partial lead loss (Schoene et al. 2010). Respecting these constraints, we may arrive at accurate correlation of periods of global environmental and biotic disturbance (from ash bed analysis

Schaltegger, Urs

2014-05-01

328

Calculations of helium production in materials irradiated at spallation neutron sources  

Microsoft Academic Search

Experience with materials irradiated in fission reactor neutron environments has shown that radiation-produced helium can exacerbate the degradation of properties caused by radiation-produced defects and defect clusters. Whereas fission-reactor neutron energies extend up to 10 MeV, the neutrons and protons at spallation neutron sources reach up to 1,000 to 2,000 MeV, and He production is much greater. For example, calculations

R. K. Corzine; D. J. Dudziak; M. S. Wechsler; M. H. Barnett; L. K. Mansur

1998-01-01

329

Conceptual design of a high-intensity positron source for the Advanced Neutron Source  

SciTech Connect

The Advanced Neutron Source (ANS) is a planned new basic and applied research facility based on a powerful steady-state research reactor that provides neutrons for measurements and experiments in the fields of materials science and engineering, biology, chemistry, materials analysis, and nuclear science. The useful neutron flux will be at least five times more than is available in the world`s best existing reactor facility. Construction of the ANS provides a unique opportunity to build a positron spectroscopy facility (PSF) with very-high-intensity beams based on the radioactive decay of a positron-generating isotope. The estimated maximum beam current is 1000 to 5000 times higher than that available at the world`s best existing positron research facility. Such an improvement in beam capability, coupled with complementary detectors, will reduce experiment durations from months to less than one hour while simultaneously improving output resolution. This facility will remove the existing barriers to the routine use of positron-based analytical techniques and will be a giant step toward realization of the full potential of the application of positron spectroscopy to materials science. The ANS PSF is based on a batch cycle process using {sup 64}Cu isotope as the positron emitter and represents the status of the design at the end of last year. Recent work not included in this report, has led to a proposal for placing the laboratory space for the positron experiments outside the ANS containment; however, the design of the positron source is not changed by that relocation. Hydraulic and pneumatic flight tubes transport the source material between the reactor and the positron source where the beam is generated and conditioned. The beam is then transported through a beam pipe to one of several available detectors. The design presented here includes all systems necessary to support the positron source, but the beam pipe and detectors have not been addressed yet.

Hulett, L.D.; Eberle, C.C.

1994-12-01

330

Room-temperature LINAC structures for the spallation neutron source  

SciTech Connect

Los Alamos National Laboratory is building room-temperature rf accelerating structures for the Spallation Neutron Source (SNS). These structures, for H{sup -} ions, consist of six 402.5-MHz, 2-MW drift-tube linac (DTL) tanks from 2.5 to 87 MeV followed by four 805-MHz, 4-MW coupled-cavity linac (CCL) modules to 186 MeV. The DTL uses permanent magnet quadrupoles inside the drift tubes arranged in a 6{beta}{lambda} FFODDO lattice with every third drift tube available for diagnostics and steering. The CCL uses a 13{beta}{lambda} FODO electromagnetic quadrupole lattice. Diagnostics and magnets occupy the 2.5{beta}{lambda} spaces between 8-cavity segments. This paper discusses design of the rf cavities and low-power modeling work.

Billen, J. H. (James H.); Young, L. M. (Lloyd M.); Kurennoy, S. (Sergey); Crandall, K. R. (Kenneth R.)

2001-04-01

331

Electron Cloud Mitigation in the Spallation Neutron Source Ring  

SciTech Connect

The Spallation Neutron Source (SNS) accumulator ring is designed to accumulate, via H{sup -} injection, protons of 2 MW beam power at 1 GeV kinetic energy at a repetition rate of 60 Hz [1]. At such beam intensity, electron-cloud is expected to be one of the intensity-limiting mechanisms that complicate ring operations. This paper summarizes mitigation strategy adopted in the design, both in suppressing electron-cloud formation and in enhancing Landau damping, including tapered magnetic field and monitoring system for the collection of stripped electrons at injection, TiN coated beam chamber for suppression of the secondary yield, clearing electrodes dedicated for the injection region and parasitic on BPMs around the ring, solenoid windings in the collimation region, and planning of vacuum systems for beam scrubbing upon operation.

Wei, J.; Blaskiewicz, Michael; Brodowski, J.; Cameron, P.; Davino, Daniele; Fedotov, A.; He, P.; Hseuh, H.; Lee, Y.Y.; Ludewig, H.; Meng, W.; Raparia, D.; Tuozzolo, J.; Zhang, S.Y.; Catalan-Lasheras, N.; Macek, R.J.; Furman, Miguel A.; Aleksandrov, A.; Cousineau, S.; Danilov, V.; Henderson, S.; /Brookhaven /CERN /LANL, Ctr. for Nonlinear Studies /LBL, Berkeley /Oak Ridge /SLAC

2008-03-17

332

SPALLATION NEUTRON SOURCE HIGH-POWER PROTECTION MODULE TEST STAND  

SciTech Connect

The Spallation Neutron Source (SNS) High-Power Protection Module (HPM) provides interlocks and fast shutdown for the radio frequency (RF) system to protect the accelerating structures and high power RF (HPRF) Distribution System. The HPM has required some functional upgrades since the start of beam operations and an upgrade to the HPM test stand was required to support these added features. The HPM test stand currently verifies functionality, RF channel calibration, and measurement of the speed of shutdown to ensure the specifications are met. The upgraded test stand was implemented in a Field Programmable Gate Array (FPGA) to allow for future growth and flexibility. Work is currently progressing on automation of the test stand to better perform the required module calibration schedule.

Lee, Sung-Woo [ORNL] [ORNL; Ball, Jeffrey Allen [ORNL] [ORNL; Crofford, Mark T [ORNL] [ORNL; Davidson Jr, Taylor L [ORNL] [ORNL; Jones, Stacey L [ORNL] [ORNL; Hardek, Thomas W [ORNL] [ORNL

2010-01-01

333

On accelerator-based neutron sources and neutron field characterization with low energy neutron spectrometer based on position sensitive 3He counter.  

PubMed

The development of new neutron sources for BNCT applications, based on particle accelerators is currently underway all over the world. Though nuclear reactors were used for a long time as the only neutron source available having the requested flux levels, the accelerator-based ones have recently been investigated on the other hand due to its easy-to-use and acceptable performances. However, when using an accelerator, various secondary particles would be emitted which forms a troublesome background. Moreover, the neutrons produced have usually an energy spectrum somewhat different from the requested one and thus should be largely moderated. An additional issue to be taken into account is the patient positioning, which should be close to the neutron source, in order to take advantage of a neutron flux level high enough to limit the BNCT treatment time within 1h. This implies that, inside a relatively narrow space, neutrons should be moderated, while unnecessary secondary particles should be shielded. Considering that a background-free neutron field from an accelerator-driven neutron source dedicated to BNCT application is generally difficult to be provided, the characterization of such a neutron field will have to be clearly assessed. In the present study, a low energy neutron spectrometer has been thus designed and is now being developed to measure the accelerator-based neutron source performance. The presently proposed spectrometer is based on a (3)He proportional counter, which is 50 cm long and 5 cm in diameter, with a gas pressure of 0.5 MPa. It is quite unique that the spectrometer is set up in parallel with the incident neutron beam and a reaction depth distribution is measured by it as a position sensitive detector. Recently, a prototype detector has been developed and the signal test is now underway. In this paper, the feature of the accelerator-based neutron sources is outlined and importance of neutron field characterization is discussed. And the developed new low energy neutron spectrometer for the characterization is detailed. PMID:19376716

Murata, I; Miyamaru, H; Kato, I; Mori, Y

2009-07-01

334

Determining 252Cf source strength by absolute passive neutron correlation counting  

NASA Astrophysics Data System (ADS)

Physically small, lightly encapsulated, radionuclide sources containing 252Cf are widely used for a vast variety of industrial, medical, educational and research applications requiring a convenient source of neutrons. For many quantitative applications, such as detector efficiency calibrations, the absolute strength of the neutron emission is needed. In this work we show how, by using a neutron multiplicity counter the neutron emission rate can be obtained with high accuracy. This provides an independent and alternative way to create reference sources in-house for laboratories such as ours engaged in international safeguards metrology. The method makes use of the unique and well known properties of the 252Cf spontaneous fission system and applies advanced neutron correlation counting methods. We lay out the foundation of the method and demonstrate it experimentally. We show that accuracy comparable to the best methods currently used by national bodies to certify neutron source strengths is possible.

Croft, S.; Henzlova, D.

2013-06-01

335

High-Power Linac for the Spallation Neutron Source  

NASA Astrophysics Data System (ADS)

The Spallation Neutron Source (SNS) will be the worlds most intense source of neutrons for fundamental science and industrial applications. Design and construction of this facility, located at Oak Ridge, is a joint venture between six DOE laboratories. Construction began in 1999 and is currently ahead of the scheduled 2006 completion date. Injecting a high-power, pulsed proton beam into a mercury target produces neutrons. In this talk, we review the physics requirements, design, and status of the construction of the 1-GeV, 1.4-MW average power RF linac for SNS. The accelerator consists of a drift tube linac (DTL), a coupled-cavity linac (CCL), and a superconducting rf (SRF) linac. The phase and quadrupole settings are set to avoid structure and parametric resonances, with coherent resonances posing minimal risk for emittance growth. The DTL is 37 m long and accelerates the ions to 87 MeV. The CCL is 55 m long and accelerates the ions to 186 MeV. The rf structure design and stability for both the DTL and CCL have been validated with scale models. The SRF linac has a modular design to accelerate ions to 1000 MeV, with a straightforward upgrade to 1.3 GeV at a later date. 3D particle-in-cell simulations of beam dynamics are performed to validate performance. The accelerator utilizes 93 MW of pulsed power operating continuously at 60-Hz with an 8factor. Approximately one hundred 402.5 or 805-MHz klystrons, with outputs between 0.55 and 5 MW, are used. The klystrons are powered by a novel converter-modulator that takes advantage of recent advances in IGBT switch plate assemblies and low-loss material cores for boost transformer. Beam diagnostics include position, phase, profile, and current monitors. They are designed to enable accurate beam steering and matching, and to minimize beam loss that would lead to activation and prevent hands-on maintenance.

Rej, D. J.

2002-04-01

336

Constraints on neutron star models of gamma-burst sources from the Einstein Observatory  

NASA Technical Reports Server (NTRS)

Six Einstein observations of five gamma-ray burst sources are presented and discussed. With one possible exception, no point source was detected in any of the observations. The data are interpreted in the framework of neutron star models for gamma bursters. Upper limits are derived for the surface temperatures of the neutron stars assumed to be responsible for the bursts. It is shown that the lack of soft X-ray emission may impose stringent constraints on accretion rates onto neutron stars.

Pizzichini, G.; Gottardi, M.; Atteia, J.-L.; Barat, C.; Hurley, K.; Niel, M.; Vedrenne, G.; Laros, J. G.; Cline, T. L.; Desai, U. D.

1986-01-01

337

Some neutron and gamma radiation characteristics of plutonium cermet fuel for isotopic power sources  

NASA Technical Reports Server (NTRS)

Gamma and neutron measurements on various types of plutonium sources are presented in order to show the effects of O-17, O-18 F-19, Pu-236, age of the fuel, and size of the source on the gamma and neutron spectra. Analysis of the radiation measurements shows that fluorine is the main contributor to the neutron yields from present plutonium-molybdenum cermet fuel, while both fluorine and Pu-236 daughters contribute significantly to the gamma ray intensities.

Neff, R. A.; Anderson, M. E.; Campbell, A. R.; Haas, F. X.

1972-01-01

338

Thermophysical properties of saturated light and heavy water for Advanced Neutron Source applications  

Microsoft Academic Search

The Advanced Neutron Source is an experimental facility being developed by Oak Ridge National Laboratory. As a new nuclear fission research reactor of unprecedented flux, the Advanced Neutron Source Reactor will provide the most intense steady-state beams of neutrons in the world. The high heat fluxes generated in the reactor [303 MW(t) with an average power density of 4.5 MW\\/L

A. Crabtree; M. Siman-Tov

1993-01-01

339

Powerful pulsed neutron sources for research with a pulsed magnetic field  

Microsoft Academic Search

The prospects for neutron investigations into the magnetic properties of condensed matter with the use of powerful pulsed\\u000a neutron sources [Japan Spallation Neutron Source (JSNS) (Tokai, Japan), TIRAN (Zababakhin All-Russia Research Institute of\\u000a Technical Physics, Russian Federal Nuclear Center, Snezhinsk, Russia), Large Hadron Collider (LHC) (CERN)] and pulsed magnetic\\u000a fields are considered. It is demonstrated that the diffraction measurements of

V. V. Nietz

2008-01-01

340

LOW LOSS DESIGN OF THE LINAC AND ACCUMULATOR RING FOR THE SPALLATION NEUTRON SOURCE  

Microsoft Academic Search

The Spallation Neutron Source (SNS) is a second generation pulsed neutron source and is presently in the fourth year of a seven-year construction cycle at Oak Ridge National Laboratory. A collaboration of six national laboratories (ANL, BNL, LANL, LBNL, ORNL, TJNAF) is responsible for the design and construction of the various subsystems. The operation of the facility will begin in

2003-01-01

341

A portable neutron\\/tunable X-ray source based on inertial electrostatic confinement  

Microsoft Academic Search

Portable neutron sources are of strong interest for uses such as industrial neutron activation analysis and various medical research applications. The inertial electrostatic confinement (IEC) device under development at the University of Illionis is intended for such uses and also provides a tunable X-ray source (required reverse bias and added electron emitters). The IEC operates as an accelerator plasma-target type

George H. Miley

1999-01-01

342

Inertial-Electrostatic Confinement Neutron\\/Proton Source  

Microsoft Academic Search

There is considerable demand in the scientific community for a neutron generator with an output of 106-108 neutrons\\/second (n\\/s) that can be switched on or off, emit fusion neutrons, be self-calibrating, and offer portable operation. An Inertial Electrostatic Confinement (IEC)-based neutron generator is proposed to meet these needs. In an IEC device, ion beams are injected into a spherical vacuum

G. H. Miley; J. Javedani; Y. Yamamoto; R. Nebel; J. Nadler; Y. Gu; A. Satsangi; P. Heck

1994-01-01

343

Development of an epithermal\\/fast neutron scattering technique for void fraction measurement in two-phase systems with portable neutron sources  

Microsoft Academic Search

A technique to measure void fraction in a two-phase flow system using the multiple scattering of neutrons from portable neutron sources was investigated. There exists evidence from a previous investigation with a neutron beam extracted from a nuclear research reactor, that the basic technique is attractive. The counting rate of multiply-scattered, thermalized neutrons was found to be nearly linear with

Peter S. L. Yuen

1985-01-01

344

Physics Analysis and Optimization Studies for a Fusion Neutron Source Based on a Gas Dynamic Trap  

NASA Astrophysics Data System (ADS)

To further investigate the fusion neutron source based on a gas dynamic trap (GDT), characteristics of the GDT were analyzed and physics analyses were made for a fusion neutron source based on the GDT concept. The prior design of a GDT-based fusion neutron source was optimized based on a refreshed understanding of GDT operation. A two-step progressive development route of a GDT-based fusion neutron source was suggested. Potential applications of GDT are discussed. Preliminary analyses show that a fusion neutron source based on the GDT concept is suitable for plasma-material interaction research, fusion material and subcomponent testing, and capable of driving a proof-of-principle fusion fission hybrid experimental facility.

Du, Hongfei; Chen, Dehong; Duan, Wenxue; Jiang, Jieqiong; Wu, Yican; FDS Team

2014-12-01

345

Computer simulations for rf design of a Spallation Neutron Source external antenna H ion source  

SciTech Connect

Electromagnetic modeling of the multicusp external antenna H ion source for the Spallation Neutron Source SNS has been performed in order to optimize high-power performance. During development of the SNS external antenna ion source, antenna failures due to high voltage and multicusp magnet holder rf heating concerns under stressful operating conditions led to rf characteristics analysis. In rf simulations, the plasma was modeled as an equivalent lossy metal by defining conductivity as . Insulation designs along with material selections such as ferrite and Teflon could be included in the computer simulations to compare antenna gap potentials, surface power dissipations, and input impedance at the operating frequencies, 2 and 13.56 MHz. Further modeling and design improvements are outlined in the conclusion.

Lee, Sung-Woo [ORNL] [ORNL; Goulding, Richard Howell [ORNL] [ORNL; Kang, Yoon W [ORNL] [ORNL; Shin, Ki [ORNL] [ORNL; Welton, Robert F [ORNL] [ORNL

2010-01-01

346

Modelling of an imaging beamline at the ISIS pulsed neutron source  

NASA Astrophysics Data System (ADS)

A combined neutron imaging and neutron diffraction facility, IMAT, is currently being built at the pulsed neutron spallation source ISIS in the U.K. A supermirror neutron guide is required to combine imaging and diffraction modes at the sample position in order to obtain suitable time of flight resolutions for energy selective imaging and diffraction experiments. IMAT will make use of a straight neutron guide and we consider here the optimization of the supermirror guide dimensions and characterisation of the resulting beam characteristics, including the homogeneity of the flux distribution in space and energy and the average and peak neutron fluxes. These investigations take into account some main design criteria: to maximise the neutron flux, to minimise geometrical artefacts in the open beam image at the sample position and to obtain a good energy resolution whilst retaining a large neutron bandwidth. All of these are desirable beam characteristics for the proposed imaging and diffraction analysis modes of IMAT.

Burca, G.; Kockelmann, W.; James, J. A.; Fitzpatrick, M. E.

2013-10-01

347

Materials Compatibility Studies for the Spallation Neutron Source  

SciTech Connect

The Spallation Neutron Source (SNS) is a high power facility for producing neutrons that utilizes flowing liquid mercury inside an austenitic stainless steel container as the target for a 1.0 GeV proton beam. The energy deposited in the target is transported by two separate mercury flow streams: one to transport heat in the interior target region and one to cool the stainless steel container. Three-dimensional computational fluid dynamics simulations have been performed to predict temperature, velocity, and pressure distributions in the target. Results have generally shown that the power deposited in the bulk mercury can be effectively transported with reasonable flow rates and the bulk mercury temperature should not exceed 160{deg}C. Assuming good thermal contact, the maximum stainless steel wall temperature should be 130 {deg}C. Type 316 SS has been selected as the container material for the mercury and consequences of exposure of 316 SS to radiation, thermal shock, thermal stress, cavitation and hot, flowing mercury are all being addressed by R&D programs. In addition, corrosion studies include evaluation of Inconel 718 because it has been successfully used in previous water cooled spallation neutron systems as a window material. With type 316 SS selected to contain the mercury target of the SNS, two types of compatibility issues have been examined: LME and temperature gradient mass transfer. Studies have shown that mercury does not easily wet type 316 SS below 275{deg}C. In the LME experiments, attempts were made to promote wetting of the steel by mercury either by adding gallium to the mercury or coating the specimen with a tin-silver solder that the mercury easily wets. The latter proved more reliable in establishing wetting, but there was no evidence of LME in any of the constant extension rate tensile tests either at 23 or 100 {deg}C. Inconel 718 also showed no change in room temperature properties when tested in mercwy or mercury-gallium. However, there was evidence that the fracture was less ductile. Preliminary evaluation of mass transfer of either type 304 SS, 316 SS, and Inconel 718 in mercury or mercury-gallium at 300-3500 C (maximum temperature) did not reveal significant effects. Two 5000 h thermal convection loop tests of type 316 SS are in progress, with specimens in both hot and cold test regions, at 300 and 240{deg}C, respectively.

DiStefano, J.R.; Manneschmidt, E.T.; Pawel, S.J.

1998-09-01

348

A neutron resonance capture analysis experimental station at the ISIS spallation source.  

PubMed

Neutron resonance capture analysis (NRCA) is a nuclear technique that is used to determine the elemental composition of materials and artifacts (e.g., bronze objects) of archaeological interest. NRCA experiments are mostly performed at the GELINA facility in Belgium, a pulsed neutron source operating with an electron linear accelerator. Very intense fluxes of epithermal neutrons are also provided by spallation neutron sources, such as the ISIS spallation neutron source in the United Kingdom. In the present study, the suitability of the Italian Neutron Experimental Station (INES) beam line for NRCA measurements is assessed using a compact (n, ?) resonance detector made of a Yttrium-Aluminum-Perovskite (YAP) scintillation crystal coupled with a silicon photomultiplier (SiPM) readout. The measurements provided a qualitative recognition of the composition of the standard sample, a lower limit for the sensitivity for NRCA for almost-in-traces elements, and an estimation of the relative isotopic concentration in the sample. PMID:20828445

Pietropaolo, Antonino; Gorini, Giuseppe; Festa, Giulia; Reali, Enzo; Grazzi, Francesco; Schooneveld, Erik M

2010-09-01

349

Multiplicity correlation between neutrons and gamma-rays emitted from SNM and non-SNM sources  

NASA Astrophysics Data System (ADS)

The challenge in detection and identification of Special Nuclear Materials (SNM) is to discriminate between the time-correlated neutrons and gamma-rays emitted from SNM and those originating from non-correlated or differently-correlated environmental non-SNM sources. Time-correlated neutron and gamma-ray bursts can be generated by penetrating components of cosmic radiation. The characteristic features or attributes of correlated signatures can be revealed by analyzing the joint probability density functions (JPDFs) of various parameters of neutrons and gamma-rays. Monte Carlo simulations of SNM and cosmic-ray (non-SNM) sources of neutrons and gamma-rays are performed. For both SNM and non-SNM sources, energy-lifetime JPDF of neutrons, energy-lifetime JPDF of gamma-rays, and JPDFs of neutron-gamma-ray multiplicity are evaluated. Mean values, standard deviations, covariance and correlation are estimated. It is found that the number (multiplicity) of neutrons and gamma-rays emitted from an SNM source is moderately correlated (?0.48). The multiplicity of neutrons and gamma-rays generated by cosmic-ray showers at sea level is only weakly correlated (?-0.046). The exploitation of neutron-gamma-ray multiplicity correlation in detectors can provide a tool to discriminate non-SNM sources.

Miloshevsky, Gennady; Hassanein, Ahmed

2015-01-01

350

Improvement in the practical implementation of neutron source strength calibration using prompt gamma rays.  

PubMed

In this study, the neutron emission rate from neutron sources using prompt gamma rays in hydrogen was determined, and several improvements were applied. Using Monte Carlo calculations, the best positions for the source, moderator and detector relative to each other were selected. For (241)Am-Be and (252)Cf sources, the sizes for polyethylene spheres with the highest efficiency were 12- and 10-inch, respectively. In addition, a new shielding cone was designed to account for scattered neutrons and gamma rays. The newly designed shielding cone, which is 45 cm in length, provided suitable attenuation for the source radiation. PMID:23672963

Khabaz, Rahim; Rene Vega-Carrillo, Hector

2013-08-01

351

The Neutron Energy Spectrum Study from the Phase II Solid Methane Moderator at the LENS Neutron Source  

E-print Network

Neutron energy spectrum measurements from a solid methane moderator were performed at the Low Energy Neutron Source (LENS) at Indiana University Cyclotron Facility (IUCF) to verify our neutron scattering model of solid methane. The time-of-flight method was used to measure the energy spectrum of the moderator in the energy range of 0.1$meV\\sim$ 1$eV$. Neutrons were counted with a high efficiency $^{3}{He}$ detector. The solid methane moderator was operated in phase II temperature and the energy spectra were measured at the temperatures of 20K and 4K. We have also tested our newly-developed scattering kernels for phase II solid methane by calculating the neutron spectral intensity expected from the methane moderator at the LENS neutron source using MCNP (Monte Carlo N-particle Transport Code). Within the expected accuracy of our approximate approach, our model predicts both the neutron spectral intensity and the optimal thickness of the moderator at both temperatures. The predictions are compared to the measured energy spectra. The simulations agree with the measurement data at both temperatures.

Yunchang Shin; W. Mike Snow; Christopher M. Lavelle; David V. Baxter; Xin Tong; Haiyang Yan; Mark Leuschner

2007-11-19

352

Neutron guide optimisation for a time-of-flight neutron imaging instrument at the European Spallation Source.  

PubMed

A neutron transport system for the planned imaging instrument ODIN at the future European Spallation Source (ESS) based on neutron optical components was designed and optimized. Different ways of prompt pulse suppression were studied. The spectral performance of the optimal neutron guide configuration is presented. In addition, the influence of the gaps in the guide system needed for the required chopper configuration was investigated. Given that the requirements for an imaging instrument located on a long guide system and hosting a complex chopper system are extremely demanding in terms of spectral and divergence needs, this study can be beneficial for a wide range of instruments in various ways. PMID:25835677

Hilger, A; Kardjilov, N; Manke, I; Zendler, C; Lieutenant, K; Habicht, K; Banhart, J; Strobl, M

2015-01-12

353

Development of k0-INAA standardization method by neutron activation with Am-Be source.  

PubMed

The k(0)-standardization method on the (241)Am-Be isotopic neutron source has been studied and developed. In this paper, the characteristics of the neutron spectrum in an isotropic neutron field of (241)Am-Be isotopic neutron sources was experimentally determined by dual monitor method using measured cadmium ratios of (197)Au(n, ?)(198)Au and (98)Mo(n, ?)(99)Mo(?(-))(99m)Tc reactions. Application of the k(0)-standardization method for the determination of elemental concentrations such as Al, Mn and Na in cement is carried out as well. The obtained results are in agreement with other analyses. PMID:22136815

Phuong, Huynh T; Nhon, Mai V; Oanh, Luu D H

2012-03-01

354

Spin-Echo Resolved Grazing Incidence Scattering (SERGIS) at Pulsed and CW Neutron Sources  

NASA Astrophysics Data System (ADS)

We have used SERGIS to probe the surface structure of a silicon diffraction grating of period 140 nm. Experiments were performed at: the Los Alamos Neutron Science Center (LANSCE) pulsed neutron source and the National Institute of Standards and Technology (NIST) continuous wave (CW) reactor neutron source. Although both sets of data show peaks of the spin echo polarization at integer multiples of the grating period, as expected, the results differ in detail. We have developed a dynamical theory, based on a Bloch wave expansion, to describe neutron diffraction from a grating. The theory explains the differences between the two sets of data without any adjustable parameters.

Ashkar, Rana; Stonaha, P.; Washington, A.; Shah, V. R.; Fitzsimmons, M. R.; Maranville, B.; Majkrzak, C. F.; Lee, W. T.; Pynn, Roger

2010-11-01

355

Startup of the High-Intensity Ultracold Neutron Source at the Paul Scherrer Institute  

E-print Network

Ultracold neutrons (UCN) can be stored in suitable bottles and observed for several hundreds of seconds. Therefore UCN can be used to study in detail the fundamental properties of the neutron. A new user facility providing ultracold neutrons for fundamental physics research has been constructed at the Paul Scherrer Institute, the PSI UCN source. Assembly of the facility finished in December 2010 with the first production of ultracold neutrons. Operation approval was received in June 2011. We give an overview of the source and the status at startup.

Bernhard Lauss

2012-02-27

356

Supercool Neutrons (Ultracold Neutrons)  

E-print Network

? How to make lots of neutrons. Interesting properties of ultracold neutrons (UCN) Supercool source of ultracold neutrons #12; What are neutrons? Neutrons are a basic constituent of matter. The atomic nucleus is made of neutrons and protons. property neutron proton electric charge 0 1e

Martin, Jeff

357

Novel neutron sources at the Radiological Research Accelerator Facility.  

PubMed

Since the 1960s, the Radiological Research Accelerator Facility (RARAF) has been providing researchers in biology, chemistry and physics with advanced irradiation techniques, using charged particles, photons and neutrons.We are currently developing a unique facility at RARAF, to simulate neutron spectra from an improvised nuclear device (IND), based on calculations of the neutron spectrum at 1.5 km from the epicenter of the Hiroshima atom bomb. This is significantly different from a standard fission spectrum, because the spectrum changes as the neutrons are transported through air, and is dominated by neutron energies between 0.05 and 8 MeV. This facility will be based on a mixed proton/deuteron beam impinging on a thick beryllium target.A second, novel facility under development is our new neutron microbeam. The neutron microbeam will, for the first time, provide a kinematically collimated neutron beam, 10-20 micron in diameter. This facility is based on a Proton Microbeam, impinging on a thin lithium target near the threshold of the (7)Li(p,n)(7)Be reaction. This novel neutron microbeam will enable studies of neutron damage to small targets, such as single cells, individual organs within small animals or microelectronic components. PMID:22545061

Xu, Yanping; Garty, Guy; Marino, Stephen A; Massey, Thomas N; Randers-Pehrson, Gerhard; Johnson, Gary W; Brenner, David J

2012-03-16

358

Novel neutron sources at the Radiological Research Accelerator Facility  

NASA Astrophysics Data System (ADS)

Since the 1960s, the Radiological Research Accelerator Facility (RARAF) has been providing researchers in biology, chemistry and physics with advanced irradiation techniques, using charged particles, photons and neutrons. We are currently developing a unique facility at RARAF, to simulate neutron spectra from an improvised nuclear device (IND), based on calculations of the neutron spectrum at 1.5 km from the epicenter of the Hiroshima atom bomb. This is significantly different from a standard fission spectrum, because the spectrum changes as the neutrons are transported through air, and is dominated by neutron energies between 0.05 and 8 MeV. This facility will be based on a mixed proton/deuteron beam impinging on a thick beryllium target. A second, novel facility under development is our new neutron microbeam. The neutron microbeam will, for the first time, provide a kinematically collimated neutron beam, 10-20 micron in diameter. This facility is based on a proton microbeam, impinging on a thin lithium target near the threshold of the 7Li(p,n)7Be reaction. This novel neutron microbeam will enable studies of neutron damage to small targets, such as single cells, individual organs within small animals or microelectronic components.

Xu, Y.; Garty, G.; Marino, S. A.; Massey, T. N.; Randers-Pehrson, G.; Johnson, G. W.; Brenner, D. J.

2012-03-01

359

A parameter study to determine the optimal source neutron energy in boron neutron capture therapy of brain tumours.  

PubMed

The values of the parameters used in boron neutron capture therapy (BNCT) to calculate a given dose to human tissue vary with patients due to different physical, biological and/or medical circumstances. Parameters include the tissue dimensions, the 10B concentration and the relative biological effectiveness (RBE) factors for the different dose components associated with BNCT. Because there is still no worldwide agreement on RBE values, more often than not, average values for these parameters are used. It turns out that the RBE-problem can be circumvented by taking into account all imaginable parameter values. Approaching this quest from another angle: the outcome will also provide the parameters (and values) which influence the optimal source neutron energy. For brain tumours it turns out that the 10B concentration, the RBE factors for 10B as well as fast neutrons, together with the dose limit set for healthy tissue, affect the optimal BNCT source neutron energy. By using source neutrons of a few keV together with neutrons of a few eV, it ensures that, under all imaginable circumstances, a maximum of alpha (and lithium) particles can be delivered in the tumour. PMID:15509065

Nievaart, V A; Moss, R L; Kloosterman, J L; van der Hagen, T H J J; van Dam, H

2004-09-21

360

Simulation of H- ion source extraction systems for the Spallation Neutron Source with Ion Beam Simulator.  

PubMed

A three-dimensional ion optical code IBSimu, which is being developed at the University of Jyva?skyla?, features positive and negative ion plasma extraction models and self-consistent space charge calculation. The code has been utilized for modeling the existing extraction system of the H(-) ion source of the Spallation Neutron Source. Simulation results are in good agreement with experimental data. A high-current extraction system with downstream electron dumping at intermediate energy has been designed. According to the simulations it provides lower emittance compared to the baseline system at H(-) currents exceeding 40 mA. A magnetic low energy beam transport section consisting of two solenoids has been designed to transport the beam from the alternative electrostatic extraction systems to the radio frequency quadrupole. PMID:22380214

Kalvas, T; Welton, R F; Tarvainen, O; Han, B X; Stockli, M P

2012-02-01

361

Control system for the Spallation Neutron Source H- source test facility Allison scannera)  

NASA Astrophysics Data System (ADS)

Spallation Neutron Source is currently in progress of a multiyear plan to ramp ion beam power to the initial design power of 1.4 MW. Key to reaching this goal is understanding and improving the operation of the H- ion source. An Allison scanner was installed on the ion source in the test facility to support this improvement. This paper will discuss the hardware and the software control system of the installed Allison scanner. The hardware for the system consists of several parts. The heart of the system is the scanner head, complete with associated bias plates, slits, and signal detector. There are two analog controlled high voltage power supplies to bias the plates in the head, and a motor with associated controller to position the head in the beam. A multifunction data acquisition card reads the signals from the signal detector, as well as supplies the analog voltage control for the power supplies. To synchronize data acquisition with the source, the same timing signal that is used to trigger the source itself is used to trigger data acquisition. Finally, there is an industrial personal computer to control the rest of the hardware. Control software was developed using National Instruments LABVIEW, and consists of two parts: a data acquisition program to control the hardware and a stand alone application for offline user data analysis.

Long, C. D.; Stockli, M. P.; Gorlov, T. V.; Han, B.; Murray, S. N.; Pennisi, T. R.

2010-02-01

362

Towards a consistent model for Neutron-Star Sources  

E-print Network

We are still far from understanding how pulsars pulse, how neutron stars are born, what neutron stars can emit, and in which way they do this. In this short communication, I list 18 alternatives -- several of them old, a few of them new -- which are handled differently by different authors but all of which are crucial for a model of neutron stars to be viable.

W. Kundt

2002-08-30

363

Assessment of the roles of the Advanced Neutron Source Operators  

SciTech Connect

The Advanced Neutron Source (ANS) is unique in the extent to which human factors engineering (HFE) principles are being applied at the conceptual design stage. initial HFE accomplishments include the development of an ANS HFE program plan, operating philosophy, and functional analysis. In FY 1994, HFE activities focused on the role of the ANS control room reactor operator (RO). An operator-centered control room model was used in conjunction with information gathered from existing ANS system design descriptions and other literature to define a list of RO responsibilities. From this list, a survey instrument was developed and administered to ANS design engineers, operations management personnel at Oak Ridge National Laboratory`s High Flux Isotope Reactor (HFIR), and HFIR ROs to detail the nature of the RO position. Initial results indicated that the RO will function as a high-level system supervisor with considerable monitoring, verification, and communication responsibilities. The relatively high level of control automation has resulted in a reshaping of the RO`s traditional safety and investment protection roles.

Hill, W.E.; Houser, M.M.; Knee, H.E.; Spelt, P.F.

1995-03-01

364

Mercury Cavitation Phenomenon in Pulsed Spallation Neutron Sources  

SciTech Connect

Innovative researches will be performed at Materials and Life Science Experimental Facility in J-PARC, in which a mercury target system will be installed as MW-class pulse spallation neutron sources. Proton beams will be injected into mercury target to induce the spallation reaction. At the moment the intense proton beam hits the target, pressure waves are generated in the mercury because of the abrupt heat deposition. The pressure waves interact with the target vessel leading to negative pressure that may cause cavitation along the vessel wall. Localized impacts by micro-jets and/or shock waves which are caused by cavitation bubble collapse impose pitting damage on the vessel wall. The pitting damage which degrades the structural integrity of target vessels is a crucial issue for high power mercury targets. Micro-gas-bubbles injection into mercury may be useful to mitigate the pressure wave and the pitting damage. The visualization of cavitation-bubble and gas-bubble collapse behaviors was carried out by using a high-speed video camera. The differences between them are recognized.

Futakawa, Masatoshi; Naoe, Takashi [Japan Atomic Energy Agency Tokai-mura, Naka-gun, Ibaraki-ken, 319-1195 (Japan); Kawai, Masayoshi [KEK Tsukuba-shi, Ibaraki-ken, 305-0801 (Japan)

2008-06-24

365

Advanced neutron source reactor probabilistic flow blockage assessment  

SciTech Connect

The Phase I Level I Probabilistic Risk Assessment (PRA) of the conceptual design of the Advanced Neutron Source (ANS) Reactor identified core flow blockage as the most likely internal event leading to fuel damage. The flow blockage event frequency used in the original ANS PRA was based primarily on the flow blockage work done for the High Flux Isotope Reactor (HFIR) PRA. This report examines potential flow blockage scenarios and calculates an estimate of the likelihood of debris-induced fuel damage. The bulk of the report is based specifically on the conceptual design of ANS with a 93%-enriched, two-element core; insights to the impact of the proposed three-element core are examined in Sect. 5. In addition to providing a probability (uncertainty) distribution for the likelihood of core flow blockage, this ongoing effort will serve to indicate potential areas of concern to be focused on in the preliminary design for elimination or mitigation. It will also serve as a loose-parts management tool.

Ramsey, C.T.

1995-08-01

366

Fuel qualification plan for the Advanced Neutron Source Reactor  

SciTech Connect

This report describes the development and qualification plan for the fuel for the Advanced Neutron Source. The reference fuel is U{sub 3}Si{sub 2}, dispersed in aluminum and clad in 6061 aluminum. This report was prepared in May 1994, at which time the reference design was for a two-element core containing highly enriched uranium (93% {sup 235}U) . The reactor was in the process of being redesigned to accommodate lowered uranium enrichment and became a three-element core containing a higher volume fraction of uranium enriched to 50% {sup 235}U. Consequently, this report was not issued at that time and would have been revised to reflect the possibly different requirements of the lower-enrichment, higher-volume fraction fuel. Because the reactor is now being canceled, this unrevised report is being issued for archival purposes. The report describes the fabrication and inspection development plan, the irradiation tests and performance modeling to qualify performance, the transient testing that is part of the safety program, and the interactions and interfaces of the fuel development with other tasks.

Copeland, G.L.

1995-07-01

367

RESULTS OF FIRST EXPERIMENTS ON NEUTRON GENERATION IN THE VITA NEUTRON SOURCE  

E-print Network

as activation detector due to capture of epithermal neutrons by iodine also. Bubble detectors were used were performed by means of PRIZMA code. Calculation of speed of detector activation had been carried of neutron generation for boron neutron capture therapy had been confirmed by current experiment

Taskaev, Sergey Yur'evich

368

Fundamental Problems of Neutron Physics at the Spallation Neutron Source at the ORNL  

Microsoft Academic Search

We propose to provide theoretical support for the experimental program in fundamental neutron physics at the SNS. This includes the study of neutron properties, neutron beta-decay, parity violation effects and time reversal violation effects. The main purpose of the proposed research is to work on theoretical problems related to experiments which have a high priority at the SNS. Therefore, we

Vladimir Gudkov

2008-01-01

369

Advanced Neutron Source Cross Section Libraries (ANSL-V): ENDF/B-V based multigroup cross-section libraries for advanced neutron source (ANS) reactor studies  

SciTech Connect

Pseudo-problem-independent, multigroup cross-section libraries were generated to support Advanced Neutron Source (ANS) Reactor design studies. The ANS is a proposed reactor which would be fueled with highly enriched uranium and cooled with heavy water. The libraries, designated ANSL-V (Advanced Neutron Source Cross Section Libraries based on ENDF/B-V), are data bases in AMPX master format for subsequent generation of problem-dependent cross-sections for use with codes such as KENO, ANISN, XSDRNPM, VENTURE, DOT, DORT, TORT, and MORSE. Included in ANSL-V are 99-group and 39-group neutron, 39-neutron-group 44-gamma-ray-group secondary gamma-ray production (SGRP), 44-group gamma-ray interaction (GRI), and coupled, 39-neutron group 44-gamma-ray group (CNG) cross-section libraries. The neutron and SGRP libraries were generated primarily from ENDF/B-V data; the GRI library was generated from DLC-99/HUGO data, which is recognized as the ENDF/B-V photon interaction data. Modules from the AMPX and NJOY systems were used to process the multigroup data. Validity of selected data from the fine- and broad-group neutron libraries was satisfactorily tested in performance parameter calculations.

Ford, W.E. III; Arwood, J.W.; Greene, N.M.; Moses, D.L.; Petrie, L.M.; Primm, R.T. III; Slater, C.O.; Westfall, R.M.; Wright, R.Q.

1990-09-01

370

Simulation calculations of transmissions for neutron total cross-section measurements of MAs and LLFPs by complementary use of a compact accelerator-driven neutron source  

NASA Astrophysics Data System (ADS)

We performed simulation calculations of neutron transmission spectra for minor actinide and long-lived fission product samples with pulsed neutron beams produced by the two neutron sources: the Accurate Neutron-Nucleus Reaction measurement Instrument (ANNRI) at the Japan Spallation Neutron Source (JSNS) that provides the world's most intense pulsed neutron beam, and a compact accelerator-driven neutron source. For the both cases, we assumed to put a neutron detector at downstream of the sample and took into account the detector efficiency of neutrons to estimate statistics. ANNRI gives high statistical neutron transmission spectra. Therefore, it is useful for obtaining the total cross-section data through the transmission spectra for the small amount sample or the small cross-section regions between the resonances not only for monitoring the beam condition during the neutron capture-reaction measurements at ANNRI. On the other hand, a compact neutron source shows transmission spectra at resonances with less deformation by its single bunch beam. This implies that the compact neutron source is useful for assigning the resonances and the resonance analysis.

Kino, Koichi; Hiraga, Fujio; Kamiyama, Takashi; Kiyanagi, Yoshiaki; Igashira, Masayuki

371

Experimental verification of beam characteristics for cyclotron-based epithermal neutron source (C-BENS).  

PubMed

A cyclotron-based epithermal neutron source has been developed for boron neutron capture therapy. This system consists of a cyclotron accelerator producing 1.1-mA proton beams with an energy of 30 MeV, a beam transport system coupled with a beryllium neutron production target, and a beam-shaping assembly (BSA) with a neutron collimator. In our previous work, the BSA was optimized to obtain sufficient epithermal neutron fluxes of ~10(9) cm(-2) s(-1) using a Monte Carlo simulation code. In order to validate the simulation results, irradiation tests using multi-foil activation at the surface of a gamma-ray shield located behind the collimator and water phantom experiments using a collimated epithermal neutron beam were performed. It was confirmed experimentally that the intensity of the epithermal neutrons was 1.210(9) cm(-2) s(-1). PMID:21463945

Tanaka, H; Sakurai, Y; Suzuki, M; Masunaga, S; Mitsumoto, T; Fujita, K; Kashino, G; Kinashi, Y; Liu, Y; Takada, M; Ono, K; Maruhashi, A

2011-12-01

372

Development of Measurement Methods for Detection of Special Nuclear Materials using D-D Pulsed Neutron Source  

NASA Astrophysics Data System (ADS)

For detection of hidden special nuclear materials (SNMs), we have developed an active neutron-based interrogation system combined with a D-D fusion pulsed neutron source and a neutron detection system. In the detection scheme, we have adopted new measurement techniques simultaneously; neutron noise analysis and neutron energy spectrum analysis. The validity of neutron noise analysis method has been experimentally studied in the Kyoto University Critical Assembly (KUCA), and was applied to a cargo container inspection system by simulation.

Misawa, Tsuyoshi; Takahashi, Yoshiyuki; Yagi, Takahiro; Pyeon, Cheol Ho; Kimura, Masaharu; Masuda, Kai; Ohgaki, Hideaki

2015-10-01

373

Shielding design studies for a neutron irradiator system based on a 252Cf source.  

PubMed

This study aims to investigate a shielding design against neutrons and gamma rays from a source of 252Cf, using Monte Carlo simulation. The shielding materials studied were borated polyethylene, borated-lead polyethylene and stainless steel. The Monte Carlo code MCNP4B was used to design shielding for 252Cf based neutron irradiator systems. By normalising the dose equivalent rate values presented to the neutron production rate of the source, the resulting calculations are independent of the intensity of the actual 252Cf source. The results show that the total dose equivalent rates were reduced significantly by the shielding system optimisation. PMID:11707031

da Silva, A X; Crispim, V R

2001-01-01

374

The ideal neutron energy spectrum of 241AmLi(?,n)10B sources.  

PubMed

The pure and unperturbed (ideal, at birth) spectra of (241)AmLi(?,n)(10)B sources were determined using Monte Carlo simulations, along with the neutron spectrum measured outside a source's encapsulation. Various parameters that affect photon and neutron yields and energy distributions were investigated. The source's microparticle size was deduced. Subsequently, the calculated theoretical neutron energy spectra of the (241)AmLi(?,n) reaction were compared to both the ideal spectra and the calculation of Geiger and van der Zwan predominantly used since early 1970s. PMID:22871444

Tagziria, H; Looman, M

2012-10-01

375

Application of fission track detectors to californium-252 neutron dosimetry in tissue near the radiation source  

Microsoft Academic Search

Fission track detectors were applied to a unique problem in neutron dosimetry. Measurements of neutron doses were required at locations within a tumor of 1 cm diameter implanted on the back of a mouse and surrounded by a square array of four ²⁵²Cf medical sources. Measurements made in a tissue-equivalent mouse phantom showed that the neutron dose rate to the

Richard A. Oswald; L. H. Lanzl; M. Rozenfeld

1981-01-01

376

Powder diffraction in materials science using the KENS cold-neutron source  

SciTech Connect

Since superconductivity fever spread around the world, neutron powder diffraction has become very popular and been widely used by crystallographers, physicists, chemists, mineralogists, and materials scientists. The purpose of present paper is to show, firstly, important characteristics of time-of-flight TOF powder diffraction using cold-neutron source in the study of materials science, and, secondly, recent studies on the structure and function of batteries at the Neutron Science Laboratory (KENS) in the High Energy Accelerator Research Organization (KEK).

Kamiyama, T.; Oikawa, K. [Univ. of Tsukuba (Japan). Inst. of Materials Science; Akiba, E. [National Inst. of Materials and Chemical Research, Tsukuba (Japan)] [and others

1997-12-01

377

Initial in-reactor performance of the Cornell cold neutron source  

Microsoft Academic Search

The Cornell Cold Neutron Beam Facility consists of two major subsystems, a cold neutron source (CNS) and a 13-m-long curved neutron guide. This paper describes the initial in-reactor performance tests of the CNS. The results agree closely with predictions from out-of-reactor tests and meet the design criteria for safety and simplicity of operation. This phase of the project has therefore

S. A. Spern; D. D. Clark; A. G. Atwood

1996-01-01

378

Plasma and current drive parameter options for a megawatt range fusion neutron source  

Microsoft Academic Search

Tokamak-based MW-range fusion neutron sources are needed for the development of innovative neutron technologies, mainly for the control of sub-critical active zones of fast nuclear reactors, for closing the nuclear fuel cycle, for neutron research purposes and also for nuclear technologies relevant to DEMO. In this paper a possibility of reducing the tokamak size while achieving steady-state plasma discharges with

B. V. Kuteev; A. A. Borisov; A. A. Golikov; V. I. Khripunov; V. E. Lukash; E. V. Popova; P. V. Savrukhin; P. R. Goncharov; V. Yu. Sergeev; M. Gryaznevich

2009-01-01

379

EURAC : a concept for a EURopean ACcelerator Neutron Source  

Microsoft Academic Search

Simulation with charaed oarticles : doa-rates 5 lo-' wsec** The Joint Research Centre (JRC) has conducted studies on the feasibility of spallation neutrons to simulate the Tokamak fusion reactor first wall conditions. It can be shown that spalla- tion neutrons, produced by 600 MeV protons impinging on a thin lead target are simulating the fusion reactor first wall con- ditions

W. Kley; G. R. Bishop; J. M. Perlado; A. Sinha

380

Radiation shielding design of BNCT treatment room for D-T neutron source.  

PubMed

Recent studies have shown that D-T neutron generator can be used as a proper neutron source for Boron Neutron Capture Therapy (BNCT) of deep-seated brain tumors. In this paper, radiation shielding calculations have been conducted based on the computational method for designing a BNCT treatment room for a recent proposed D-T neutron source. By using the MCNP-4C code, the geometry of the treatment room has been designed and optimized in such a way that the equivalent dose rate out of the treatment room to be less than 0.5?Sv/h for uncontrolled areas. The treatment room contains walls, monitoring window, maze and entrance door. According to the radiation protection viewpoint, dose rate results of out of the proposed room showed that using D-T neutron source for BNCT is safe. PMID:25732097

Pouryavi, Mehdi; Farhad Masoudi, S; Rahmani, Faezeh

2015-05-01

381

A laser-induced repetitive fast neutron source applied for gold activation analysis  

SciTech Connect

A laser-induced repetitively operated fast neutron source was developed for applications in laser-driven nuclear physics research. The developed neutron source, which has a neutron yield of approximately 4 Multiplication-Sign 10{sup 5} n/pulse and can be operated up to a pulse repetition rate of 10 Hz, was applied for a gold activation analysis. Relatively strong delayed gamma spectra of the activated gold were measured at 333 keV and 355 keV, and proved the possibility of the neutron source for activation analyses. In addition, the nuclear reactions responsible for the measured gamma spectra of gold were elucidated by the 14 MeV fast neutrons resulting from the D(t,n)He{sup 4} nuclear reaction, for which the required tritium originated from the primary fusion reaction, D(d,p)T{sup 3}.

Lee, Sungman; Park, Sangsoon; Lee, Kitae; Cha, Hyungki [Quantum Optics Division, Korea Atomic Energy Research Institute, Daejeon 305-600 (Korea, Republic of)

2012-12-15

382

High-Resolution Measurements of Neutron Energy Spectra from Americium-Beryllium and Americium-Boron Neutron Sources  

NASA Astrophysics Data System (ADS)

Available from UMI in association with The British Library. A Helium-3 sandwich spectrometer incorporating two semiconductor detectors was designed and constructed to enable the measurement of high resolution neutron energy spectra in the energy range from 100 keV to 15 MeV. The instrument is novel in respect of the inclusion of an anode wire which enables the gas chamber to function as a gas proportional counter. Few similar instruments have been constructed and no similar instrument is known to be currently (1990) in use in the UK. The efficiency of the spectrometer was determined experimentally, using a Californium-252 spontaneous fission source, in the low-scatter facility of the National physical Laboratory. A Monte Carlo code has been written to determine the absolute efficiency over an energy range from 81 keV to 20 MeV. The calculated values were used to extrapolate the measured efficiency to higher energies. Furthermore the Monte Carlo code was used to determine certain operating parameters to optimise the efficiency of the spectrometer. The neutron energy spectra from two different size standard Am-Be neutron sources and a standard Am-B neutron source available at NPL were measured. Although these types of neutron sources have been subject to energy spectra measurements elsewhere, the present work improves considerably on the previous poorer energy resolution and energy range. The new data indicates for the three neutron sources studied that the ambient dose equivalent, H*(10) per unit fluence, for each, were identical, being within 2% of 3.70 E-10 Sv cm^2.

Marsh, James W.

383

An accelerator-based epithermal photoneutron source for boron neutron capture therapy  

SciTech Connect

Boron neutron capture therapy is an experimental binary cancer radiotherapy modality in which a boronated pharmaceutical that preferentially accumulates in malignant tissue is first administered, followed by exposing the tissue in the treatment volume to a thermal neutron field. Current usable beams are reactor-based but a viable alternative is the production of an epithermal neutron beam from an accelerator. Current literature cites various proposed accelerator-based designs, most of which are based on proton beams with beryllium or lithium targets. This dissertation examines the efficacy of a novel approach to BNCT treatments that incorporates an electron linear accelerator in the production of a photoneutron source. This source may help to resolve some of the present concerns associated with accelerator sources, including that of target cooling. The photoneutron production process is discussed as a possible alternate source of neutrons for eventual BNCT treatments for cancer. A conceptual design to produce epithermal photoneutrons by high photons (due to bremsstrahlung) impinging on deuterium targets is presented along with computational and experimental neutron production data. A clinically acceptable filtered epithermal neutron flux on the order of 10{sup 7} neutrons per second per milliampere of electron current is shown to be obtainable. Additionally, the neutron beam is modified and characterized for BNCT applications by employing two unique moderating materials (an Al/AlF{sub 3} composite and a stacked Al/Teflon design) at various incident electron energies.

Mitchell, H.E.

1996-04-01

384

Calculation of the top beryllium shim plate worths for the syrian miniature neutron source reactor  

Microsoft Academic Search

A calculation of the reactivity worths of the top beryllium shim plates in the Miniature Neutron Source Reactor (MNSR) is presented. Modification of the earlier developed 3-D (r, ?, z) neutronic model, as well a 2-D model, for the MNSR are discussed. Results of the 2-D and 3-D models are compared. Both results agree very well with the corresponding experimentally

K. Khattab; I. Khamis

2004-01-01

385

Fabrication and characterization of the source grating for visibility improvement of neutron phase imaging with gratings  

SciTech Connect

The fabrication of gratings including metal deposition processes for highly neutron absorbing lines is a critical issue to achieve a good visibility of the grating-based phase imaging system. The source grating for a neutron Talbot-Lau interferometer is an array of Gadolinium (Gd) structures that are generally made by sputtering, photo-lithography, and chemical wet etching. However, it is very challenging to fabricate a Gd structure with sufficient neutron attenuation of approximately more than 20 {mu}m using a conventional metal deposition method because of the slow Gd deposition rate, film stress, high material cost, and so on. In this article, we fabricated the source gratings for neutron Talbot-Lau interferometers by filling the silicon structure with Gadox particles. The new fabrication method allowed us a very stable and efficient way to achieve a much higher Gadox filled structure than a Gd film structure, and is even more suitable for thermal polychromatic neutrons, which are more difficult to stop than cold neutrons. The newly fabricated source gratings were tested at the polychromatic thermal neutron grating interferometer system of HANARO at the Korea Atomic Energy Research Institute, and the visibilities and images from the neutron phase imaging system with the new source gratings were compared with those fabricated by a Gd deposition method.

Kim, Jongyul [Neutron Science Division, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Nuclear and Quantum Engineering Department, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); Lee, Kye Hong; Lim, Chang Hwy; Kim, Taejoo [Neutron Science Division, Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Ahn, Chi Won [Nano Fusion Technology Division, National Nanofab Center, Daejeon 305-701 (Korea, Republic of); Cho, Gyuseong [Nuclear and Quantum Engineering Department, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); Lee, Seung Wook [School of Mechanical Engineering, Pusan National University, Pusan 609-735 (Korea, Republic of)

2013-06-15

386

Materials research and development for the spallation neutron source mercury target  

Microsoft Academic Search

In the Spallation Neutron Source target, the structural material will be exposed to intense pulsed fluxes of high-energy protons and neutrons, which produce radiation damage. These pulsed fluxes also lead to pressure pulses created by beam heating. In turn, the pressure pulses give rise to fluctuating stresses in the 316 LN austenitic stainless steel target vessel, and to cavitation in

L. K. Mansur

2003-01-01

387

Gas dynamic trap as high power 14 MeV neutron source  

Microsoft Academic Search

It is now widely recognized that further progress toward a commercial fusion reactor critically depends on the availability of low activated materials to be operated for many years in the fusion neutron environment without degradation of their properties. Therefore, high power neutron source (NS) for extensive material tests is in great demand. The realistic NS can be built on the

P. A. Bagryansky; A. A. Ivanov; E. P. Kruglyakov; A. M. Kudryavtsev; Yu. A. Tsidulko; A. V. Andriyash; A. L. Lukin; Yu. N. Zouev

2004-01-01

388

Heuristic derivation of the Rossi-alpha formula for a pulsed neutron source  

Microsoft Academic Search

Expressions for the Rossi-alpha distribution for a pulsed neutron source were derived using a heuristic derivation based on the method of joint detection probability. This heuristic technique was chosen over the more rigorous master equation method due to its simplicity and the complementary of both techniques. The derived equations also take into account the presence of delayed neutrons and intrinsic

P. Baeten

2004-01-01

389

Thermal-hydraulic analysis of the Advanced Neutron Source reactor refueling process  

Microsoft Academic Search

The Advanced Neutron Source Reactor (ANSR) is being designed to become the world's most advanced reactor for neutron scattering research. It is both moderated and cooled by heavy water (D[sub 2]O) and uses a core of highly enriched uranium silicide fuel in a plate geometry. During the refueling process of the ANSR, the spent fuel must be moved from within

Y. Elkassabgi; G. L. Yoder; W. R. Gambill

1994-01-01

390

HYSPEC : A CRYSTAL TIME OF FLIGHT HYBRID SPECTROMETER FOR THE SPALLATION NEUTRON SOURCE  

Microsoft Academic Search

This document lays out a proposal by the Instrument Development Team (IDT) composed of scientists from leading Universities and National Laboratories to design and build a conceptually new high-flux inelastic neutron spectrometer at the pulsed Spallation Neutron Source (SNS) at Oak Ridge. This instrument is intended to supply users of the SNS and scientific community, of which the IDT is

S. M. SHAPIRO; I. A. ZALIZNYAK

2002-01-01

391

Intense Pulsed Neutron Source progress report for 1991  

SciTech Connect

The IPNS Progress Report 10th Anniversary Edition is being published in recognition of the first ten years of successful IPNS operation. To emphasize the significance of this milestone, we wanted this report to stand apart from the previous IPNS Progress Reports, and the best way to do this, we thought, was to make the design and organization of the report significantly different. In their articles, authors were asked to emphasize not only advances made since IPNS began operating but also the groundwork that was laid at its predecessor facilities - Argonne`s ZING-P and ZING-P` prototype pulsed neutron sources and CP-5 reactor. Each article stands as a separate chapter in the report, since each represents a particular instrument or class of instruments, system, technique, or area of research. In some cases, contributions were similar to review articles in scientific journals, complete with extensive lists of references. Ten-year cumulative lists of members of IPNS committees and of scientists who have visited or done experiments at IPNS were assembled. A list of published and ``in press`` articles in journals, books, and conference proceedings, resulting from work done at IPNS during the past ten years, was compiled. And archival photographs of people and activities during the ten-year history of IPNS were located and were used liberally throughout the report. The titles of the chapters in this report are: accelerator; computer; radiation effects; powder; stress; single crystal; superconductivity; amorphous; small angle; reflection; quasielastic; inelastic; inelastic magnetic; deep inelastic; user program; the future; and publications.

Not Available

1991-12-31

392

Intense Pulsed Neutron Source progress report for 1991  

SciTech Connect

The IPNS Progress Report 10th Anniversary Edition is being published in recognition of the first ten years of successful IPNS operation. To emphasize the significance of this milestone, we wanted this report to stand apart from the previous IPNS Progress Reports, and the best way to do this, we thought, was to make the design and organization of the report significantly different. In their articles, authors were asked to emphasize not only advances made since IPNS began operating but also the groundwork that was laid at its predecessor facilities - Argonne's ZING-P and ZING-P' prototype pulsed neutron sources and CP-5 reactor. Each article stands as a separate chapter in the report, since each represents a particular instrument or class of instruments, system, technique, or area of research. In some cases, contributions were similar to review articles in scientific journals, complete with extensive lists of references. Ten-year cumulative lists of members of IPNS committees and of scientists who have visited or done experiments at IPNS were assembled. A list of published and in press'' articles in journals, books, and conference proceedings, resulting from work done at IPNS during the past ten years, was compiled. And archival photographs of people and activities during the ten-year history of IPNS were located and were used liberally throughout the report. The titles of the chapters in this report are: accelerator; computer; radiation effects; powder; stress; single crystal; superconductivity; amorphous; small angle; reflection; quasielastic; inelastic; inelastic magnetic; deep inelastic; user program; the future; and publications.

Not Available

1991-01-01

393

76 FR 76327 - Installation of Radiation Alarms for Rooms Housing Neutron Sources  

Federal Register 2010, 2011, 2012, 2013, 2014

...NUCLEAR REGULATORY COMMISSION...NRC-2011-0251] Installation of Radiation Alarms for Rooms Housing...Neutron Sources AGENCY: Nuclear Regulatory Commission...require installation of radiation alarms for rooms housing...December 2011. For the Nuclear Regulatory...

2011-12-07

394

Designing and testing the neutron source deployment system and calibration plan for a dark matter detector  

E-print Network

In this thesis, we designed and tested a calibration and deployment system for the MiniCLEAN dark matter detector. The deployment system uses a computer controlled winch to lower a canister containing a neutron source into ...

Westerdale, Shawn (Shawn S.)

2011-01-01

395

Monte Carlo calculation of skyshine'' neutron dose from ALS (Advanced Light Source)  

SciTech Connect

This report discusses the following topics on skyshine'' neutron dose from ALS: Sources of radiation; ALS modeling for skyshine calculations; MORSE Monte-Carlo; Implementation of MORSE; Results of skyshine calculations from storage ring; and Comparison of MORSE shielding calculations.

Moin-Vasiri, M.

1990-06-01

396

Studies in neutron phase space cooling for cold and ultra-cold neutron sources  

Microsoft Academic Search

This thesis addresses problems in the phase space compression of neutrons in two different energy regimes. The first part applies to the cold neutron regime. We constructed a microscopic model for the neutron dynamic structure factor S(Q, o) of solid methane in phase II. The model treats the effects of molecular translations, intra-molecular vibrations and intra-molecular rotations as uncoupled. Total

Yunchang Shin

2008-01-01

397

Determination of a CR-39 detector response to neutrons from an Am-Be source.  

PubMed

A comparison of experimental and calculated responses of a CR-39 detector to neutron spectra from an Am-Be source is presented. Code named Neutron_CR-39.F90 has been used to calculate the neutron dose equivalent as well as the track density. Conversion coefficient (sensitivity), between track density in track/cm(2) and neutron dose equivalent in mSv, was calculated and good agreement with experimental data was found. Sensitivity increases linearly with removed layer in the range between 6 ?m and 24 ?m. PMID:24814609

Milenkovic, B; Stevanovic, N; Nikezic, D; Kosutic, D

2014-08-01

398

Separation of beam and electrons in the spallation neutron source H{sup -} ion source  

SciTech Connect

The Spallation Neutron Source (SNS) requires an ion source producing an H{sup {minus}} beam with a peak current of 35mA at a 6.2 percent duty factor. For the design of this ion source, extracted electrons must be transported and dumped without adversely affecting the H{sup {minus}} beam optics. Two issues are considered: (1) electron containment transport and controlled removal; and (2) first-order H{sup {minus}} beam steering. For electron containment, various magnetic, geometric and electrode biasing configurations are analyzed. A kinetic description for the negative ions and electrons is employed with self-consistent fields obtained from a steady-state solution to Poisson`s equation. Guiding center electron trajectories are used when the gyroradius is sufficiently small. The magnetic fields used to control the transport of the electrons and the asymmetric sheath produced by the gyrating electrons steer the ion beam. Scenarios for correcting this steering by split acceleration and focusing electrodes will be considered in some detail.

Whealton, J.H.; Raridon, R.J. [Oak Ridge National Lab., TN (United States); Leung, K.N. [Lawrence Berkeley National Lab., CA (United States)

1997-12-01

399

Advances in the Rietveld method for time-of-flight neutron powder diffraction at pulsed neutron sources  

Microsoft Academic Search

The recent development of accelerator-based pulsed neuron sources has led to the widespread use of the time-of-flight technique for neutron powder diffraction. The properties of the pulsed source make possible unusually high resolution over a wide range of d spacings, high count rates, and the ability to collect complete data at fixed scattering angles. The peak shape and other instrument

W. I. F. David; J. D. Jorgensen

1990-01-01

400

Geometrical effects on thermal neutron reflection of hydrogenous moderators using 241Am-Be source  

Microsoft Academic Search

The variation of thermal reflection parameter with thicknesses of water and paraffin moderators was measured using an instrument consisting of 1 Ci 241AmBe isotopic neutron source and 3He neutron detector. Based on experimental data obtained from two different sourcedetectorsample geometries, analytical expressions were derived for calculation of reflection parameters for various moderator thicknesses. The measured data for the two geometries

E. H. K. Akaho; S. A. Jonah; C. P. K Dagadu; B. T. Maakuu; P. S. Adu; S. Anim-Sampong; A. W. K. Kyere

2001-01-01

401

Measurements of energy spectra and doses in liquid air of neutrons from a californium-252 source  

Microsoft Academic Search

To provide data for testing nitrogen and oxygen cross-section sets, transport of neutrons from a ²⁵²Cf source was investigated in a large volume of liquid air. Neutron energy spectra and doses were measured at distances between 30 and 230 cm from the source. Proton recoil proportional counters and NE-213 scintillation detectors were used to obtain energy spectra from 40 keV

K. Clausen; U. Roose; P. Schneider-Kuehnle; F. W. Buchholz; L. Schaenzler; S. Stueker; G. Tumbraegel; M. Weinert

1977-01-01

402

Rietveld refinement with time-of-flight powder diffraction data from pulsed neutron sources  

Microsoft Academic Search

The recent development of accelerator-based pulsed neutron sources has led to the widespread use of the time-of-flight technique for neutron powder diffraction. The properties of the pulsed source make possible unusually high resolution over a wide range of d spacings, high count rates, and the ability to collect complete data at fixed scattering angles. The peak shape and other instrument

W. I. F. David; J. D. Jorgensen

1990-01-01

403

Comparison of flux density distributions from massive or ring-shaped isotopic neutron sources  

Microsoft Academic Search

A comparison has been made between flux density distributions from massive and ring-shaped cylindrical isotopic neutron sources.\\u000a A considerable gain in direct fast neutron flux is obtained for the latter geometry as well as a neat separation of fast and\\u000a thermal flux density maxima along the axis of the source. Applications of these favourable properties are discussed.

L. Alaerts; J. P. Op De Beeck; J. Hoste

1975-01-01

404

Study on low activation decoupler material for MW-class spallation neutron sources  

Microsoft Academic Search

The Japan Spallation Neutron Source (JSNS) at the Japan Proton Accelerator Research Complex (J-PARC) has started its operation on May 30, 2008. The AgInCd (AIC) alloy was adopted as a decoupler material for two decoupled moderators. A high decoupling energy at 1eV was for the first time achieved in MW-class spallation neutron sources due to the adoption of the AIC

M. Harada; M. Teshigawara; F. Maekawa; M. Futakawa

2010-01-01

405

Preliminary probabilistic design accident evaluation of the cold source facilities of the advanced neutron source  

SciTech Connect

Consistent with established Advanced Neutron Source (ANS) project policy for the use of probabilistic risk assessment (PRA) in design, a task has been established to use PRA techniques to help guide the design and safety analysis of the ANS cold sources. The work discussed in this report is the first formal output of the cold source PRA task. The major output at this stage is a list of design basis accidents, categorized into approximate frequency categories. This output is expected to focus attention on continued design work to define and optimize the design such that design basis accidents are better defined and have acceptable outcomes. Categorizing the design basis events (DBEs) into frequency categories should prove helpful because it will allow appropriate acceptance criteria to be applied. Because the design of the cold source is still proceeding, it is beyond the scope of this task to produce detailed event probability calculations or even, in some cases, detailed event sequence definitions. That work would take place as a logically planned follow-on task, to be completed as the design matures. Figure 1.1 illustrates the steps that would typically be followed in selecting design basis accidents with the help of PRA. Only those steps located above the dashed line on Fig. 1.1 are included in the scope of the present task. (Only an informal top-level failure modes and effects analysis was done.) With ANS project closeout expected in the near future, the scope of this task has been abbreviated somewhat beyond the state of available design information on the ANS cold sources, or what could be achieved in a reasonable time. This change was necessary to ensure completion before the closeout and because the in-depth analytical support necessary to define fully some of the accidents has already been curtailed.

Harrington, R.M.; Ramsey, C.T.

1995-08-01

406

BINP accelerator based epithermal neutron source V. Aleynik a  

E-print Network

to a directed neutron flow and low background radiation. All problems of a lithium target have been solved. To determine the total beam current in different parts of the facility, a target like a copper cone with water

Taskaev, Sergey Yur'evich

407

Gamma-ray measurements at the WNR white neutron source  

Microsoft Academic Search

Photon production data have been acquired in the incident neutron energy range, 1 < E{sub n} < 400 MeV, for a number of target nuclei, gamma-ray energy ranges, and reactions, using the continuous-energy neutron beam of the WNR facility at Los Alamos. Gamma-ray production measurements using high resolution Ge detectors have been employed for gamma-rays in the energy range, 0.1

R. O. Nelson; S. A. Wender; D. R. Mayo

1994-01-01

408

The dependence of the gravity effect in elliptic neutron guides on the source size  

NASA Astrophysics Data System (ADS)

Elliptic neutron guides are expected to be widely used for construction of long neutron beamlines at the future European Spallation Source and other facilities due to their superiour transmission properties compared to conventional straight guides. At the same time, neutrons traveling long distances are subject to the action of gravity that can significantly modify their flight paths. In this work, the influence of gravity on a neutron beam propagating through elliptic guides is studied for the first time in a systematic way with Monte-Carlo simulations. It is shown that gravity leads to significant distortions of the phase space during propagation through long elliptic guides, but this effect can be recovered by a sufficiently large source size. The results of this analysis should be taken into account during design of long neutron instruments at the ESS and other facilities.

Nekrassov, D.; Zendler, C.; Lieutenant, K.

2014-07-01

409

Prompt-gamma neutron activation analysis system design: effects of D-T versus D-D neutron generator source selection  

Technology Transfer Automated Retrieval System (TEKTRAN)

Prompt-gamma neutron activation analysis (PGNAA) is used for the non-invasive measurement of human body composition. Advancements in portable, compact neutron generator design have made those devices attractive as neutron sources. Two distinct generators are available: D-D with 2.5 MeV, and D-T wi...

410

Prompt-gamma neutron activation analysis system design: Effects of D-T versus D-D neutron generator source selection  

Technology Transfer Automated Retrieval System (TEKTRAN)

Prompt-gamma neutron activation (PGNA) analysis is used for the non-invasive measurement of human body composition. Advancements in portable, compact neutron generator design have made those devices attractive as neutron sources. Two distinct generators are available: D-D with 2.5 MeV and D-T with...

411

Accelerator driven subcritical system as a future neutron source in Kyoto University Research Reactor Institute (KURRI) Basic study on neutron multiplication in the accelerator driven subcritical reactor  

Microsoft Academic Search

A basic study on the nuclear characteristics in the accelerator driven subcritical reactor (ADSR) was performed through a series of neutronics calculations in view of a future neutron source in Kyoto University Research Reactor Institute (KURRI) for the joint use program among researchers of Japanese universities. In this series of calculations, it was assumed that three kinds of monoenergetic neutrons

S. Shiroya; H. Unesaki; Y. Kawase; H. Moriyama; M. Inoue

2000-01-01

412

Evaluation of neutron sources for ISAGE-in-situ-NAA for a future lunar mission.  

PubMed

For a future Moon landing, a concept for an in-situ NAA involving age determination using the (40)Ar-(39)Ar method is developed. A neutron source (252)Cf is chosen for sample irradiation on the Moon. A special sample-in-source irradiation geometry is designed to provide a homogeneous distribution of neutron flux at the irradiation position. Using reflector, the neutron flux is likely to increase by almost 200%. Sample age of 1Ga could be determined. Elemental analysis using INAA is discussed. PMID:21680192

Li, X; Breitkreutz, H; Burfeindt, J; Bernhardt, H-G; Trieloff, M; Hopp, J; Jessberger, E K; Schwarz, W H; Hofmann, P; Hiesinger, H

2011-11-01

413

An Ultracold Neutron Source for 1. Introduction to Ultracold Neutrons (UCN)  

E-print Network

Recoil separator 132Sn stored in ring interacts with free neutron (UCN) target. 132Sn current 5e17 /s UCNV Interactions: gravity: V=mgh (h density. TRIUMF has the potential to be a world leader in this regard. #12;Gravity V = mgh For a neutron

Martin, Jeff

414

How Argonne's Intense Pulsed Neutron Source came to life and gained its niche : the view from an ecosystem perspective  

Microsoft Academic Search

At first glance the story of the Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory (ANL) appears to have followed a puzzling course. When researchers first proposed their ideas for an accelerator-driven neutron source for exploring the structure of materials through neutron scattering, the project seemed so promising that both Argonne managers and officials at the laboratory's funding agency,

C. Westfall

2008-01-01

415

Irradiation facility for boron neutron capture therapy application based on a rf-driven D-T neutron source and a new beam shaping assembly (abstract)  

NASA Astrophysics Data System (ADS)

Selecting the best neutron source for boron neutron capture therapy (BNCT) requires optimizing neutron beam parameters. This involves solving many complex problems. Safety issues related to the use of nuclear reactor in hospital environments, as well as lower costs have led to interest in the development of accelerator-driven neutron sources. The BNCT research programs at the Nuclear Departments of Pisa and Genova Universities (DIMNP and DITEC) focus on studies of new concepts for accelerator-based DT neutron sources. Simple and compact accelerator designs using relatively low deuteron beam energy, 100 keV, have been developed which, in turn, can generate high neutron yields. New studies have been started for optimization of moderator materials for the 14.1 MeV DT neutrons. Our aim is to obtain an epithermal neutron beam for therapeutic application at the exit end, with minimal beam intensity losses, the specific goal is to achieve an epithermal neutron flux of at least of 1109 n/cm2 s at the beam port, with low gamma and fast neutron dose contamination. According to the most recent neutron BNCT beam parameters some moderating and spectrum shifter materials and geometrical configurations have thus far been tested, and neutron and gamma beam data at beam port have been computed. A possible beam shaping assembly model has been designed. This research demonstrates that a DT neutron source could be successfully implemented for BNCT application, with performance surpassing the minimum requirements stated above, using DT neutron sources with yields in the range 1013-1014 n/s. The latest Monte Carlo simulation results of an accelerator based facility which relies on a rf-driven DT fusion neutron generator will be presented.

Cerullo, N.; Esposito, J.; Leung, K. N.

2002-02-01

416

A Fast Pulsed Neutron Source for Time-of-Flight Detection of Nuclear Materials and Explosives  

NASA Astrophysics Data System (ADS)

AASC has built a fast pulsed neutron source based on the Dense Plasma Focus (DPF). The more current version stores only 100 J but fires at 10-50 Hz and emits 106n/pulse at a peak current of 100 kA. Both sources emit 2.450.1 MeV (DD) neutron pulses of 25-40 ns width. Such fast, quasi-monoenergetic pulses allow time-of-flight detection of characteristic emissions from nuclear materials or high explosives. A test is described in which iron targets were placed at different distances from the point neutron source. Detectors such as Stilbene and LaBr3 were used to capture inelastically induced, 847 keV gammas from the iron target. Shielding of the source and detectors eliminated most (but not all) of the source neutrons from the detectors. Gated detection, pulse shape analysis and time-of-flight discrimination enable separation of gamma and neutron signatures and localization of the target. A Monte Carlo simulation allows evaluation of the potential of such a fast pulsed source for a field-portable detection system. The high rep-rate source occupies two 200 liter drums and uses a cooled DPF Head that is <500 cm3 in volume.

Krishnan, Mahadevan; Bures, Brian; James, Colt; Madden, Robert; Hennig, Wolfgang; Breus, Dimitry; Asztalos, Stephen; Sabourov, Konstantin; Lane, Stephen

2011-12-01

417

Fundamental Problems of Neutron Physics at the Spallation Neutron Source at the ORNL  

SciTech Connect

We propose to provide theoretical support for the experimental program in fundamental neutron physics at the SNS. This includes the study of neutron properties, neutron beta-decay, parity violation effects and time reversal violation effects. The main purpose of the proposed research is to work on theoretical problems related to experiments which have a high priority at the SNS. Therefore, we will make a complete analysis of beta-decay process including calculations of radiative corrections and recoil corrections for angular correlations for polarized neutron decay, with an accuracy better that is supposed to be achieved in the planning experiments. Based on the results of the calculations, we will provide analysis of sensitivity of angular correlations to be able to search for the possible extensions of the Standard model. Also we will help to plan other experiments to address significant problems of modern physics and will work on their theoretical support.

Vladimir Gudkov

2008-07-16

418

Time-Resolved High Resolution Neutron Imaging Studies at the ORNL Spallation Neutron Source  

Microsoft Academic Search

Our evaluation of a high-resolution digital imaging detector capable of providing millisecond time resolution and high sensitivity for neutrons is presented. This detector is a modified version of the high-resolution gamma-ray imager developed previously at Radiation Monitoring Devices, Inc. (RMD, Inc.), and consists of an Electron Multiplying Charge Coupled Device (EMCCD) attached to a neutron-sensitive scintillator via a fiberoptic taper.

Vivek V. Nagarkar; Dayakar Penumadu; Irina Shestakova; Samta C. Thacker; Stuart R. Miller; John F. Ankner; Hassina Z. Bilheux; Candice E. Halbert

2009-01-01

419

A Targeted Search for Point Sources of EeV Neutrons  

NASA Astrophysics Data System (ADS)

A flux of neutrons from an astrophysical source in the Galaxy can be detected in the Pierre Auger Observatory as an excess of cosmic-ray air showers arriving from the direction of the source. To avoid the statistical penalty for making many trials, classes of objects are tested in combinations as nine "target sets," in addition to the search for a neutron flux from the Galactic center or from the Galactic plane. Within a target set, each candidate source is weighted in proportion to its electromagnetic flux, its exposure to the Auger Observatory, and its flux attenuation factor due to neutron decay. These searches do not find evidence for a neutron flux from any class of candidate sources. Tabulated results give the combined p-value for each class, with and without the weights, and also the flux upper limit for the most significant candidate source within each class. These limits on fluxes of neutrons significantly constrain models of EeV proton emission from non-transient discrete sources in the Galaxy.

Aab, A.; Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Samarai, I. Al; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Aramo, C.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Badescu, A. M.; Barber, K. B.; Buml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blmer, H.; Boh?ov, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Chavez, A. G.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Collica, L.; Coluccia, M. R.; Conceio, R.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Criss, A.; Cronin, J.; Curutiu, A.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; de Jong, S. J.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Daz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; Dova, M. T.; Ebr, J.; Engel, R.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fernandes, M.; Fick, B.; Figueira, J. M.; Filevich, A.; Filip?i?, A.; Fox, B. D.; Fratu, O.; Frhlich, U.; Fuchs, B.; Fuji, T.; Gaior, R.; Garca, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gate, F.; Gemmeke, H.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Giller, M.; Glaser, C.; Glass, H.; Gomez Albarracin, F.; Gmez Berisso, M.; Gmez Vitale, P. F.; Gonalves, P.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Hasankiadeh, Q. D.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Hrandel, J. R.; Horvath, P.; Hrabovsk, M.; Huber, D.; Huege, T.; Insolia, A.; Isar, P. G.; Islo, K.; Jandt, I.; Jansen, S.; Jarne, C.; Josebachuili, M.; Kp, A.; Kambeitz, O.; Kampert, K. H.; Kasper, P.; Katkov, I.; Kgl, B.; Keilhauer, B.; Keivani, A.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Krause, R.; Krohm, N.; Krmer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kunka, N.; La Rosa, G.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leo, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; Lpez, R.; Lopez Agera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Malacari, M.; Maldera, S.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Mari?, I. C.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martnez Bravo, O.; Martraire, D.; Masas Meza, J. J.; Mathes, H. J.; Mathys, S.; Matthews, A. J.; Matthews, J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Messina, S.; Meyhandan, R.; Mi?anovi?, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morello, C.; Moreno, J. C.; Mostaf, M.; Moura, C. A.; Muller, M. A.; Mller, G.; Mnchmeyer, M.; Mussa, R.; Navarra, G.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Noka, L.; Ochilo, L.; Olinto, A.; Oliveira, M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Papenbreer, P.; Parente, G.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; Pe?ala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Peters, C.; Petrera, S.; Petrolini, A.; Petrov, Y.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Porcelli, A.; Porowski, C.; Privitera, P.; Prouza, M.; Purrello, V.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.

2014-07-01

420

High energy particle background at neutron spallation sources and possible solutions  

NASA Astrophysics Data System (ADS)

Modern spallation neutron sources are driven by proton beams ~ GeV energies. Whereas low energy particle background shielding is well understood for reactors sources of neutrons (~20 MeV), for high energies (100s MeV to multiple GeV) there is potential to improve shielding solutions and reduce instrument backgrounds significantly. We present initial measured data on high energy particle backgrounds, which illustrate the results of particle showers caused by high energy particles from spallation neutron sources. We use detailed physics models of different materials to identify new shielding solutions for such neutron sources, including laminated layers of multiple materials. In addition to the steel and concrete, which are used traditionally, we introduce some other options that are new to the neutron scattering community, among which there are copper alloys as used in hadronic calorimeters in high energy physics laboratories. These concepts have very attractive energy absorption characteristics, and simulations predict that the background suppression could be improved by one or two orders of magnitude. These solutions are expected to be great benefit to the European Spallation Source, where the majority of instruments are potentially affected by high energy backgrounds, as well as to existing spallation sources.

Cherkashyna, N.; Kanaki, K.; Kittelmann, T.; Filges, U.; Deen, P.; Herwig, K.; Ehlers, G.; Greene, G.; Carpenter, J.; Connatser, R.; Hall-Wilton, R.; Bentley, P. M.

2014-07-01

421

Modified big bang nucleosynthesis with nonstandard neutron sources  

NASA Astrophysics Data System (ADS)

During big bang nucleosynthesis, any injection of extra neutrons around the time of the Be7 formation, i.e. at a temperature of order T ?50 keV, can reduce the predicted freeze-out amount of Be7+Li7 that otherwise remains in sharp contradiction with the Spite plateau value inferred from the observations of Pop II stars. However, the growing confidence in the primordial D /H determinations puts a strong constraint on any such scenario. We address this issue in detail, analyzing different temporal patterns of neutron injection, such as decay, annihilation, resonant annihilation, and oscillation between mirror and standard model world neutrons. For this latter case, we derive the realistic injection pattern taking into account thermal effects (damping and refraction) in the primordial plasma. If the extra-neutron supply is the sole nonstandard mechanism operating during the big bang nucleosynthesis, the suppression of lithium abundance below Li /H?1.910-10 always leads to the overproduction of deuterium, D /H?3.610-5, well outside the error bars suggested by recent observations.

Coc, Alain; Pospelov, Maxim; Uzan, Jean-Philippe; Vangioni, Elisabeth

2014-10-01

422

Modified big bang nucleosynthesis with non-standard neutron sources  

E-print Network

During big bang nucleosynthesis, any injection of extra neutrons around the time of the $^7$Be formation, i.e. at a temperature of order $T \\simeq 50$~keV, can reduce the predicted freeze-out amount of $^7$Be + $^7$Li that otherwise remains in sharp contradiction with the Spite plateau value inferred from the observations of Pop II stars. However, the growing confidence in the primordial D/H determinations puts a strong constraint on any such scenario. We address this issue in detail, analyzing different temporal patterns of neutron injection, such as decay, annihilation, resonant annihilation, and oscillation between mirror and standard model world neutrons. For this latter case, we derive the realistic injection pattern taking into account thermal effects (damping and refraction) in the primordial plasma. If the extra neutron supply is the sole non-standard mechanism operating during the BBN, the suppression of lithium abundance below Li/H~$\\leq 1.9 \\times 10^{-10}$ always leads to the overproduction of deuterium, D/H~$\\geq 3.6 \\times 10^{-5}$, well outside the error bars suggested by recent observations.

Alain Coc; Maxim Pospelov; Jean-Philippe Uzan; Elisabeth Vangioni

2014-05-07

423

Relation of university research reactors to the advanced neutron source  

Microsoft Academic Search

For the past two decades, the Europeans have had a model enterprise for the execution and exploitation of neutron research. It is based on a single large and highly capable central facility - the Institut Laue-Langevin (ILL) - and a considerable number of smaller research reactors at universities and government laboratories in various countries. New experimental techniques and instruments have

J. B. Hayter; T. J. McManamy; C. D. West

1994-01-01

424

Standardisation of water-moderated 241Am-Be neutron source using De Pangher neutron long counter: experimental and Monte Carlo modelling.  

PubMed

A convenient neutron source is made for calibration of neutron survey instruments and personal dosimeters that are used in various nuclear installations such as fuel reprocessing, waste management, fuel fabrication and oil and well logging facilities, etc. This source consists of a bare (241)Am-Be neutron source placed at the centre of a 15-cm radius stainless steel spherical shell filled with distilled water. This paper describes the standardisation of the source at Bhabha Atomic Research Centre, using De Pangher neutron long counter both experimentally and using the Monte Carlo simulation. The ratio of neutron yield of water moderated to the bare (241)Am-Be neutron source was found to be 0.573. From the simulation, the neutron-fluence-weighted average energy of water-moderated (241)Am-Be source (fluence-weighted average energy of 2.25 MeV, dose-weighted average energy of 3.55 MeV) was found to be nearly the same as that of a (252)Cf source (fluence-weighted average energy of 2.1 MeV, dose-weighted average energy of 2.3 MeV). This source can be used for calibration in addition to (252)Cf, to study the variation in response of neutron monitoring instruments. PMID:21498862

Ghodke, Shobha; Kumari, Sujatha; Singh, Yashoda; Sathian, V; Mahant, A K; Sharma, D N

2012-02-01

425

Monte-Carlo simulations of small angle neutron scattering instruments at European spallation source  

NASA Astrophysics Data System (ADS)

Monte-Carlo simulations of small angle neutron scattering (SANS) instruments have been performed using the VITESS software package in order to investigate the performance of such neutron spectrometers at high-power spallation sources as European spallation source (ESS). The performed simulations show that a low Q-range SANS instrument down to Q=310-4 -1 can be suitably built using a 60 m free neutron flight path (30 m collimation length and 30 m sample to detector distance) and a wavelength range up to 20 . Free neutron flight paths of 30 and 4 m with wavelength ranges of 4.6-6.5 and of 4.6-10 cover accessible Q-ranges of 210 -3-610 -2 and 210 -2-0.45 -1, respectively, with fair resolution and large overlap regions. The total length of the instrument would be 66 m from source to detector. Instruments with significantly larger neutron flight paths show no further gain in its performance. Highest count rates were received at the proposed long pulse target station of ESS with up to an order of magnitude intensity gain compared to the proposed short pulse target station of ESS or the ILL as neutron source in the three wavelength ranges anticipated.

Lieutenant, K.; Gutberlet, T.; Wiedenmann, A.; Mezei, F.

2005-11-01

426

The Neutron Science TeraGrid Gateway, a TeraGrid Science Gateway to Support the Spallation Neutron Source  

SciTech Connect

The National Science Foundation's (NSF's) Extensible Terascale Facility (ETF), or TeraGrid [1] is entering its operational phase. An ETF science gateway effort is the Neutron Science TeraGrid Gateway (NSTG.) The Oak Ridge National Laboratory (ORNL) resource provider effort (ORNL-RP) during construction and now in operations is bridging a large scale experimental community and the TeraGrid as a large-scale national cyberinfrastructure. Of particular emphasis is collaboration with the Spallation Neutron Source (SNS) at ORNL. The U.S. Department of Energy's (DOE's) SNS [2] at ORNL will be commissioned in spring of 2006 as the world's brightest source of neutrons. Neutron science users can run experiments, generate datasets, perform data reduction, analysis, visualize results; collaborate with remotes users; and archive long term data in repositories with curation services. The ORNL-RP and the SNS data analysis group have spent 18 months developing and exploring user requirements, including the creation of prototypical services such as facility portal, data, and application execution services. We describe results from these efforts and discuss implications for science gateway creation. Finally, we show incorporation into implementation planning for the NSTG and SNS architectures. The plan is for a primarily portal-based user interaction supported by a service oriented architecture for functional implementation.

Cobb, John W [ORNL; Geist, Al [ORNL; Kohl, James Arthur [ORNL; Miller, Stephen D [ORNL; Peterson, Peter F [ORNL; Pike, Gregory [ORNL; Reuter, Michael A [ORNL; Swain, William [ORNL; Vazhkudai, Sudharshan S [ORNL; Vijayakumar, Nithya N [ORNL

2006-01-01

427

Neutron production using a pyroelectric driven target coupled with a gated field ionization source  

SciTech Connect

A palm sized, portable neutron source would be useful for widespread implementation of detection systems for shielded, special nuclear material. We present progress towards the development of the components for an ultracompact neutron generator using a pulsed, meso-scale field ionization source, a deuterated (or tritiated) titanium target driven by a negative high voltage lithium tantalate crystal. Neutron production from integrated tests using an ion source with a single, biased tungsten tip and a 3 Multiplication-Sign 1 cm, vacuum insulated crystal with a plastic deuterated target are presented. Component testing of the ion source with a single tip produces up to 3 nA of current. Dielectric insulation of the lithium tantalate crystals appears to reduce flashover, which should improve the robustness. The field emission losses from a 3 cm diameter crystal with a plastic target and 6 cm diameter crystal with a metal target are compared.

Ellsworth, J. L.; Tang, V.; Falabella, S. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550 (United States); Naranjo, B.; Putterman, S. [University of California Los Angeles, 405 Hilgard Ave., Los Angeles, CA 90095 (United States)

2013-04-19

428

Performance evaluation of the source description of the THOR BNCT epithermal neutron beam.  

PubMed

This paper aims to evaluate the performance of the source description of the THOR BNCT beam via different measurement techniques in different phantoms. The measurement included (1) the absolute reaction rate measurement of a set of triple activation foils, (2) the neutron and gamma-ray dose rates measured using the paired ionization chamber method, and (3) the relative reaction rate distributions obtained using the indirect neutron radiography. Three source descriptions, THOR-Y09, surface source file RSSA, and THOR-50C, were tested. The comparison results concluded that THOR-Y09 is a well-tested source description not only for neutron components, but also for gamma-ray component. PMID:21570855

Liu, Yuan-Hao; Tsai, Pi-En; Yu, Hui-Ting; Lin, Yi-Chun; Huang, Yu-Shiang; Huang, Chun-Kai; Liu, Yen-Wan Hsueh; Liu, Hong-Ming; Jiang, Shiang-Huei

2011-12-01

429

Secondary Startup Neutron Sources as a Source of Tritium in a Pressurized Water Reactor (PWR) Reactor Coolant System (RCS)  

SciTech Connect

The hypothesis of this paper is that the Zircaloy clad fuel source is minimal and that secondary startup neutron sources are the significant contributors of the tritium in the RCS that was previously assigned to release from fuel. Currently there are large uncertainties in the attribution of tritium in a Pressurized Water Reactor (PWR) Reactor Coolant System (RCS). The measured amount of tritium in the coolant cannot be separated out empirically into its individual sources. Therefore, to quantify individual contributors, all sources of tritium in the RCS of a PWR must be understood theoretically and verified by the sum of the individual components equaling the measured values.

Shaver, Mark W.; Lanning, Donald D.

2010-02-01

430

Proceedings of the workshop on ion source issues relevant to a pulsed spallation neutron source: Part 2 workshop presentations  

SciTech Connect

As part of the Lawrence Berkeley Laboratory Pulsed Spallation Source study, this Workshop was convened to address ion-source technology`s present status with respect to the next-generation Pulsed Spallation Source in the 1-5 MW range for the neutron scattering community. Considerations of Low Energy Beam Transport (LEBT) parameters and designs were included in the discussions throughout the Workshop. Ion-source requirements and actually-achieved performances were assessed, resulting in a determination of research and development requirements to bridge the gap. Part 1 of these Proceedings summarizes the Workshop; Part 2 contains viewgraphs of Workshop presentations.

Schroeder, L.; Leung, Ka-Ngo; Alonso, J. [eds.

1994-10-01

431

Verifying the Asymmetric Multiple Position Neutron Source (AMPNS) method using the TRIGA reactor  

SciTech Connect

A new experimental/analytical method has been developed using the Penn State Breazeale (TRIGA) reactor, to measure the k{sub eff} of a damaged core, e.g., the TMI-2 core, and unfold its k{sub infinity} distribution. This new method, the Asymmetric Multiple Position Neutron Source (AMPNS) method, uses the response of several neutron detectors in fixed positions around the core periphery (and possibly in the core) when a neutron source is placed sequentially in different discrete core positions. Experiments have been performed with the Penn State Breazeale TRIGA Reactor (PSBR) and analyzed with appropriate neutron calculations, using PSU-LEOPARD and EXTERMINATOR-II (EXT-II), to verify the method.

Kim, Soon-Sam; Leyine, S.H. [Pennsylvania State University, College Park, PA (United States)

1984-07-01

432

Evaluation of the characteristics of the neutron reference field using D2O-moderated 252Cf source.  

PubMed

The ambient/personal dose equivalent per fluence for D(2)O moderated (252)Cf neutron source was determined by measurement. An appropriate subtraction of the scattered neutrons is required for the accurate measurement of direct neutrons. A cubic shadow object was used for the subtraction of the scattered neutrons from the surroundings. The scattered neutrons to be subtracted vary with the position of the shadow object due to the large volume of the source. Using the Monte Carlo code MCNP-4C, the optimum positions of the shadow object were surveyed for subtracting the scattered neutrons. The energy spectra of direct neutrons were measured in the optimum position. The dosimetric parameters for the D(2)O moderated (252)Cf neutron source were reasonable, taking into account the uncertainties of the parameters. PMID:17525058

Kowatari, M; Fujii, K; Takahashi, M; Yoshizawa, M; Shimizu, S; Kawasaki, K; Yamaguchi, Y

2007-01-01

433

Ultracold neutron source at the PULSTAR reactor: Engineering design and cryogenic testing  

NASA Astrophysics Data System (ADS)

Construction is completed and commissioning is in progress for an ultracold neutron (UCN) source at the PULSTAR reactor on the campus of North Carolina State University. The source utilizes two stages of neutron moderation, one in heavy water at room temperature and the other in solid methane at ~ 40 K, followed by a converter stage, solid deuterium at 5 K, that allows a single down scattering of cold neutrons to provide UCN. The UCN source rolls into the thermal column enclosure of the PULSTAR reactor, where neutrons will be delivered from a bare face of the reactor core by streaming through a graphite-lined assembly. The source infrastructure, i.e., graphite-lined assembly, heavy-water system, gas handling system, and helium liquefier cooling system, has been tested and all systems operate as predicted. The research program being considered for the PULSTAR UCN source includes the physics of UCN production, fundamental particle physics, and material surface studies of nanolayers containing hydrogen. In the present paper we report details of the engineering and cryogenic design of the facility as well as results of critical commissioning tests without neutrons.

Korobkina, E.; Medlin, G.; Wehring, B.; Hawari, A. I.; Huffman, P. R.; Young, A. R.; Beaumont, B.; Palmquist, G.

2014-12-01

434

Feasibility study of a volumetric neutron source based on a superconducting tokamak device  

Microsoft Academic Search

We design a volumetric neutron source based on a steady-state tokamak device with superconducting coils. It is found that the neutron flux of 1 MW\\/m2 is available in the medium-sized device (R=4.5 m, a=1.0 m, ?=1.8 and Ip=5.6 MA) under the conditions of H=2 and ?N=3 with a NBI power of 60 MW. We demonstrate the controllability of the current

Y. Ogawa; T. Amano; Y. Asaoka; R. Hiwatari; N. Inoue; Y. Murakami; K. Okano; K. Tokimatsu; K. Tomabechi; T. Yamamoto; T. Yoshida

1997-01-01

435

Compact, Energy Self-Sustaining Neutron Source: Enabling Technology for Various Applications  

Microsoft Academic Search

In this novel neutron source, a deuterium beam (energy of about 100 keV) is to be injected through a Plasma Window into a tube filled with tritium gas or tritium plasma to generate D-T fusion reactions whose products are 14.06 MeV neutrons and 3.52 MeV alpha particles. At the opposite end of the tube, the energy of deuterium ions that

Ady Hershcovitch; W. Horak; B. Johnson; M. Todosow; T. Roser; M. Driscoll

2008-01-01

436

A volumetric neutron source for fusion nuclear technology testing and development  

Microsoft Academic Search

Research and development (R&D) needs to construct and operate fusion nuclear technology (FNT) components for DEMO have been investigated. Non-fusion facilities, i.e. non-neutron test stands, fission reactors and accelerator- based neutron sources, can and should play a role in FNT R&D because of their availability and low cost. However, none of the FNT critical issues will be resolved by testing

Mohamed A. Abdou

1995-01-01

437

Research and Development of Compact Neutron Sources based on Inertial Electrostatic Confinement Fusion  

Microsoft Academic Search

Recent progress is described in the research and development of an inertial-electrostatic confinement fusion (IECF) device. Use of a water-cooling jacket with non-uniform thickness shows promising success for landmine detection application, such as effective channeling of neutron flux toward the target and a very stable dc yield in excess of 107 D-D neutrons\\/sec. Addition of an ion source to the

Kai Masuda; Teruhisa Takamatsu; Kiyoshi Yoshikawa; Tsuyoshi Misawa; Seiji Shiroya; Yoshiyuki Takahashi; Takeshi Fujimoto; Tomoya Nakagawa; Taiju Kajiwara; Kazunobu Nagasaki

2009-01-01

438

Commissioning of the Superconducting Linac at the Spallation Neutron Source (SNS)  

Microsoft Academic Search

The use of superconducting radiofrequency (SRF) cavities in particle accelerator is becoming more widespread. Among the projects that make use of that technology is the Spallation Neutron Source, where H-ions are accelerated to about 1 GeV, mostly making use of niobium elliptical cavities. SNS will use the accelerated short (about 700 ns) sub-bunches of protons to generate neutrons by spallation,

Sang-Ho Kim; Isidoro E. Campisi

2007-01-01

439

Inertial-confinement ion-beam wet-wood-burner fusion neutron source  

Microsoft Academic Search

The scientific feasibility of a wet-wood-burner (WWB) concept of a fusion neutron source that is based on direct interaction between a deuterium ion beam and a tritium target is investigated. Simple one- and two-dimensional analytic models are developed and used for estimating the range of neutron yields and fusion energy gains, Q, attainable from the inertial confinement ion beam WWB

A. Birnboim; E. Greenspan; D. Shvarts

1979-01-01

440

Baseline design of a low energy neutron source at ESS-Bilbao  

NASA Astrophysics Data System (ADS)

This article briefly describes the basic design of the ESS-Bilbao neutron target station as well as its expected neutronic performance. The baseline engineering design, associated ancillary systems, and plant layout for the facility is now complete. A rotating target composed of twenty beryllium plates has been selected as the best choice in terms of both neutron yield and engineering complexity. It will provide neutron beams with a source term of 1015 n s?1 resulting from the direct 9Be(p, xn) reaction using a 75 mA proton beam at 50 MeV. The design envisages a target station equipped with two fully optimized moderators capable of withstanding a proton-beam power of 112 kW. This design is flexible enough to accommodate future upgrades in final proton energy. The envisaged neutron-beam brightness will enable several applications, including the use of cold and thermal neutrons for condensed matter research as well as fast-neutron irradiation studies. We close by discussing the role that this facility may play once the European Spallation Source becomes operational in Lund, Sweden.

Sordo, F.; Fernandez-Alonso, F.; Gonzalez, Miguel A.; Ghiglino, A.; Magn, M.; Terrn, S.; Martnez, F.; de Vicente, J. P.; Vivanco, R.; Bermejo, F. J.; Perlado, J. M.

2014-10-01

441

Progress toward the development and testing of source reconstruction methods for NIF neutron imaginga)  

NASA Astrophysics Data System (ADS)

Development of analysis techniques for neutron imaging at the National Ignition Facility is an important and difficult task for the detailed understanding of high-neutron yield inertial confinement fusion implosions. Once developed, these methods must provide accurate images of the hot and cold fuels so that information about the implosion, such as symmetry and areal density, can be extracted. One method under development involves the numerical inversion of the pinhole image using knowledge of neutron transport through the pinhole aperture from Monte Carlo simulations. In this article we present results of source reconstructions based on simulated images that test the methods effectiveness with regard to pinhole misalignment.

Loomis, E. N.; Grim, G. P.; Wilde, C.; Wilson, D. C.; Morgan, G.; Wilke, M.; Tregillis, I.; Merrill, F.; Clark, D.; Finch, J.; Fittinghoff, D.; Bower, D.

2010-10-01

442

Collinear Cluster Tripartition as a Neutron Source--Evaluation of the Setup Parameters  

SciTech Connect

Forthcoming experiments aimed at studying the mechanism of collinear cluster tripartition are planning to be performed with the new facility. Charged products will be registered with the double arm time-of-flight spectrometer composed of mosaics of PIN -diodes and MCP (micro channel plates) based timing detectors. Several tens of {sup 3}He-filled counters will be gathered round the {sup 252}Cf source. In order to choose an optimal configuration of the neutron detector and other parameters of the experiment special modeling has performed using both 'neutron barrel' and known MCNP code. The first test run of the new facility is in progress also its 'neutron skin' in under construction.

Kamanin, D. V.; Kuznetsova, E. A.; Aleksandrov, A. A.; Aleksandrova, I. A.; Borzakov, S. B.; Chelnokov, M. L.; Pham Minh, D.; Kondratyev, N. A.; Kopach, Yu. N.; Panteleev, Ts.; Penionzhkevich, Yu. E.; Svirikhin, A. I.; Sokol, E. A.; Testov, D. A.; Zhuchko, V. E.; Yeremin, A. V. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Pyatkov, Yu. V. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Moscow Engineering Physics Institute, 115409 Moscow (Russian Federation); Jacobs, N. [Faculty of Military Science, Military Academy, Stellenbosch University, Saldanha 7395 (South Africa); Ryabov, Yu. V. [Institute for Nuclear Research RAN, 117312 Moscow (Russian Federation)

2010-04-30

443

Development of target system for intense neutron source of p-Li reaction.  

PubMed

A target cooling system was developed for an intense neutron source of p-Li reaction. The system consists of target cooling devices and protection devices for lithium evaporation. A pin-structure cooling device was developed to enhance cooling power. Functional graded material was utilized for the evaporation of lithium. Test experiments were performed by using the neutron exposure accelerator system for biological effect experiments (NASBEE) at the National Institute of Radiological Sciences (NIRS) in Japan. The target system was confirmed to be applicable for accelerator-based boron neutron capture therapy. PMID:24786900

Kamada, So; Takada, Masashi; Suda, Mitsuru; Hamano, Tsuyoshi; Imaseki, Hitoshi; Hoshi, Masaharu; Fujii, Ryo; Nakamura, Masaru; Sato, Hitoshi; Higashimata, Atsushi; Arai, Seiji

2014-06-01

444

Detailed flux calculations for the conceptual design of the Advanced Neutron Source Reactor  

SciTech Connect

A detailed MCNP model of the Advanced Neutron Source Reactor has been developed. All reactor components inside the reflector tank were included, and all components were highly segmented. Neutron and photon multigroup flux spectra have been calculated for each segment in the model, and thermal-to-fast neutron flux ratios were determined for each component segment. Axial profiles of the spectra are provided for all components of the reactor. Individual segment statistical uncertainties were limited wherever possible, and the group fluxes for all important reflector components have a standard deviation below 10%.

Wemple, C.A. [EG and G Idaho, Inc., Idaho Falls, ID (United States)

1995-05-01

445

Lowering the enrichment of the Syrian miniature neutron source reactor  

Microsoft Academic Search

An investigation of lowering the fuel enrichment of MNSR was realized. A 3-D neutronic model was developed for the analysis of the reactor. It was found that lower number of fuel elements is needed when UO2 is used with 5.45g of 235U content in each fuel rod. Sensitivity of the reactor to the purity of the beryllium reflector proved to

I Khamis; K Khattab

1999-01-01

446

Ring energy and current considerations for spallation neutron source  

Microsoft Academic Search

The most desirable energy E{sub o} of protons from the synchrotron and thus beam current {bar I} to produced a given beam power P{sub B} involves a balanced consideration of neutron production capability, accelerator beam stability, user requirements, and cost considerations. The present solution consists of two 3.6-GeV rings with a 600-MeV Linac injector, a compromise between conflicting factors of

Blumberg

1994-01-01

447