Inertial electrostatic confinement I(IEC) neutron sources

International Nuclear Information System (INIS)

Nebel, R.A.; 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

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

Using FLUKA to Study Concrete Square Shield Performance in Attenuation of Neutron Radiation Produced by APF Plasma Focus Neutron Source

Science.gov (United States)

Nemati, M. J.; Habibi, M.; Amrollahi, R.

2013-04-01

In 2010, representatives from the Nuclear Engineering and physics Department of Amirkabir University of Technology (AUT) requested development of a project with the objective of determining the performance of a concrete shield for their Plasma Focus as neutron source. The project team in Laboratory of Nuclear Engineering and physics department of Amirkabir University of Technology choose some shape of shield to study on their performance with Monte Carlo code. In the present work, the capability of Monte Carlo code FLUKA will be explored to model the APF Plasma Focus, and investigating the neutron fluence on the square concrete shield in each region of problem. The physical models embedded in FLUKA are mentioned, as well as examples of benchmarking against future experimental data. As a result of this study suitable thickness of concrete for shielding APF will be considered.

NSPEC - A neutron spectrum code for beam-heated fusion plasmas

International Nuclear Information System (INIS)

Scheffel, J.

1983-06-01

A 3-dimensional computer code is described, which computes neutron spectra due to beam heating of fusion plasmas. Three types of interactions are considered; thermonuclear of plasma-plasma, beam-plasma and beam-beam interactions. Beam deposition is modelled by the NFREYA code. The applied steady state beam distribution as a function of pitch angle and velocity contains the effects of energy diffusion, friction, angular scattering, charge exchange, electric field and source pitch angle distribution. The neutron spectra, generated by Monte-Carlo methods, are computed with respect to given lines of sight. This enables the code to be used for neutron diagnostics. (author)

The continued development of the Spallation Neutron Source external antenna H- ion source

International Nuclear Information System (INIS)

Welton, R. F.; Carmichael, J.; Fuga, R.; Goulding, R. H.; Han, B.; Kang, Y.; Lee, S. W.; Murray, S. N.; Pennisi, T.; Potter, K. G.; Santana, M.; Stockli, M. P.; Desai, N. J.

2010-01-01

The U.S. Spallation Neutron Source (SNS) is an accelerator-based, pulsed neutron-scattering facility, currently in the process of ramping up neutron production. In order to ensure that the SNS will meet its operational commitments as well as provide for future facility upgrades with high reliability, we are developing a rf-driven, H - ion source based on a water-cooled, ceramic aluminum nitride (AlN) plasma chamber. To date, early versions of this source have delivered up to 42 mA to the SNS front end and unanalyzed beam currents up to ∼100 mA (60 Hz, 1 ms) to the ion source test stand. This source was operated on the SNS accelerator from February to April 2009 and produced ∼35 mA (beam current required by the ramp up plan) with availability of ∼97%. During this run several ion source failures identified reliability issues, which must be addressed before the source re-enters production: plasma ignition, antenna lifetime, magnet cooling, and cooling jacket integrity. This report discusses these issues, details proposed engineering solutions, and notes progress to date.

The plasma focus as a large fluence neutron source

International Nuclear Information System (INIS)

Zucker, O.; Bostick, W.; Long, J.; Luce, J.; Sahlin, H.

1977-01-01

A continuously operated, 1 pps, dense-plasma-focus device capable of delivering a minimum of 10 15 neutrons per pulse for material testing purposes is described. With I 5 scaling, predicted from analysis of existing machines, yields of 10 16 -10 17 neutrons per pulse are postulated. The average power consumption, which has become a major issue as a result of the energy crisis is shown to be highly favorable. A novel approach to the capacitor bank and switch design allowing repetitive operation is discussed. (Auth.)

Optimisation of the neutron source based on gas dynamic trap for transmutation of radioactive wastes

Science.gov (United States)

Anikeev, Andrey V.

2012-06-01

The Budker Institute of Nuclear Physics in collaboration with the Russian and foreign organizations develop the project of 14 MeV neutron source, which can be used for fusion material studies and for other application. The projected neutron source of plasma type is based on the plasma Gas Dynamic Trap (GDT), which is a special magnetic mirror system for plasma confinement. Presented work continues the subject of development the GDT-based neutron source (GDT-NS) for hybrid fusion-fission reactors. The paper presents the results of recent numerical optimization of such neutron source for transmutation of the long-lives radioactive wastes in spent nuclear fuel.

Influence of neutron scattering and source extent on the measurement of neutron energy spectra at ASDEX

International Nuclear Information System (INIS)

Huebner, K.; Baetzner, R.; Roos, M.; Robouch, B.V.; Ingrosso, L.; Wurz, H.

1987-08-01

The problem of nuclear emulsion measurements at ASDEX is considered. Besides the application of the VINIA-3DAMC software, this needs a description of the plasma neutron source, a model of the ASDEX structure, and calculation of the response of the nuclear emulsion to the incoming spectral neutron fluence. The latter is essential for comparing the numerical results with measurements at ASDEX. To treat this part, the NEPMC software was developed. The aim of the present work is to demonstrate the feasibility, reliability and usefulness of the method. Therefore simplified treatments for the ASDEX model, the plasma neutron source and the track statistics in the NEPMC software were used. Such calculations are of interest not only for nuclear emulsion measurements as well as any other neutron diagnostics, but also for all problems of neutron shielding for other diagnostics. (orig./GG)

Dense Plasma Focus - From Alternative Fusion Source to Versatile High Energy Density Plasma Source for Plasma Nanotechnology

Science.gov (United States)

Rawat, R. S.

2015-03-01

The dense plasma focus (DPF), a coaxial plasma gun, utilizes pulsed high current electrical discharge to heat and compress the plasma to very high density and temperature with energy densities in the range of 1-10 × 1010 J/m3. The DPF device has always been in the company of several alternative magnetic fusion devices as it produces intense fusion neutrons. Several experiments conducted on many different DPF devices ranging over several order of storage energy have demonstrated that at higher storage energy the neutron production does not follow I4 scaling laws and deteriorate significantly raising concern about the device's capability and relevance for fusion energy. On the other hand, the high energy density pinch plasma in DPF device makes it a multiple radiation source of ions, electron, soft and hard x-rays, and neutrons, making it useful for several applications in many different fields such as lithography, radiography, imaging, activation analysis, radioisotopes production etc. Being a source of hot dense plasma, strong shockwave, intense energetic beams and radiation, etc, the DPF device, additionally, shows tremendous potential for applications in plasma nanoscience and plasma nanotechnology. In the present paper, the key features of plasma focus device are critically discussed to understand the novelties and opportunities that this device offers in processing and synthesis of nanophase materials using, both, the top-down and bottom-up approach. The results of recent key experimental investigations performed on (i) the processing and modification of bulk target substrates for phase change, surface reconstruction and nanostructurization, (ii) the nanostructurization of PLD grown magnetic thin films, and (iii) direct synthesis of nanostructured (nanowire, nanosheets and nanoflowers) materials using anode target material ablation, ablated plasma and background reactive gas based synthesis and purely gas phase synthesis of various different types of

Dense Plasma Focus - From Alternative Fusion Source to Versatile High Energy Density Plasma Source for Plasma Nanotechnology

International Nuclear Information System (INIS)

Rawat, R S

2015-01-01

The dense plasma focus (DPF), a coaxial plasma gun, utilizes pulsed high current electrical discharge to heat and compress the plasma to very high density and temperature with energy densities in the range of 1-10 × 10 10 J/m 3 . The DPF device has always been in the company of several alternative magnetic fusion devices as it produces intense fusion neutrons. Several experiments conducted on many different DPF devices ranging over several order of storage energy have demonstrated that at higher storage energy the neutron production does not follow I 4 scaling laws and deteriorate significantly raising concern about the device's capability and relevance for fusion energy. On the other hand, the high energy density pinch plasma in DPF device makes it a multiple radiation source of ions, electron, soft and hard x-rays, and neutrons, making it useful for several applications in many different fields such as lithography, radiography, imaging, activation analysis, radioisotopes production etc. Being a source of hot dense plasma, strong shockwave, intense energetic beams and radiation, etc, the DPF device, additionally, shows tremendous potential for applications in plasma nanoscience and plasma nanotechnology. In the present paper, the key features of plasma focus device are critically discussed to understand the novelties and opportunities that this device offers in processing and synthesis of nanophase materials using, both, the top-down and bottom-up approach. The results of recent key experimental investigations performed on (i) the processing and modification of bulk target substrates for phase change, surface reconstruction and nanostructurization, (ii) the nanostructurization of PLD grown magnetic thin films, and (iii) direct synthesis of nanostructured (nanowire, nanosheets and nanoflowers) materials using anode target material ablation, ablated plasma and background reactive gas based synthesis and purely gas phase synthesis of various different types of

Home brew technetium : clinical scale desktop plasma fusion neutron source to produce Tc99m as an alternative to industrial scale fission reactor sources

International Nuclear Information System (INIS)

Bosi, S.G.; Khachan, J.; Oborn, B.M.

2011-01-01

Full text: Tc-99m (decay product of Mo-99) accounts for ∼ 90% of world's production of radiopharmaceuticals. Recent unexpected shutdowns of two fission reactors and routine maintenance closures .e created a global shortage of Tc-99m, hence the large global effort to find alternative sources. This project aims to design and produce a novel prototype Mo-99/Tc-99m source. An operational desktop neutron source is available at the University of Sydney, employing a deuterium fusion-plasma to create 2.45 MeV neutrons. These neutrons will be used to activate Mo-98 thin an activation vessel. In one embodiment, the activation vessel contains an aqueous slurry or gel containing Mo-98 which converts to 0-99 upon activation. The decay product Tc-99m could then be milked, similar to existing Tc-99m generators. Monte Carlo will be :ed to assess yield versus size and geometry for various vessel designs. The neutron source filled with deuterium operating at 250 W, produces 3 x 106 neutrons continuously. The neutron flux can be increased ∼ 100-fold if the fill gas is 50% tritium and by another ∼ 100-1000-fold by increasing the power. This is being designed for local use, perhaps on the scale f one or a few hospitals, so the yield would not need to be industrial ;ale as with fission reactor sources. This device is low cost <$300 K) compared with cyclotrons and fission reactors.

Proceedings of the Japan-U.S. workshop P-119 on 14 MeV neutron source for material R and D based on plasma devices

International Nuclear Information System (INIS)

Miyahara, A.; Coensgen, F.H.

1988-06-01

In addition to the development of an adequate means to contain reacting D-T plasma in the range of 100 million deg K, the successful development of nuclear fusion as an energy source requires the development of new long-lived, low-activation materials. These new fusion reactor materials should not become radioactive when subjected to intense neutron irradiation for a long period. If the induced radioactivity cannot be entirely avoided, it must be short-lived and at relatively low level. The material development is already in progress using existing fission irradiation facilities and low level 14 MeV neutron sources. But the final selection and qualification of fusion reactor materials will require end of life testing. The neutron irradiation facilities for this purpose, the approximation of D-T neutron spectrum and the design of fusion material irradiation test (FMIT) are discussed. The workshop P-119 was organized to promote the development of plasma-based neutron sources. The presentation of each concept included its physics basis, neutron field characteristics, the required research and development and their schedules, and the rough estimation of the costs for development, construction and operation. (K.I.)

Laser heated solenoid as a neutron source facility

International Nuclear Information System (INIS)

Steinhauer, L.C.; Rose, P.H.

1975-01-01

Conceptual designs are presented for a radiation test facility based on a laser heated plasma confined in a straight solenoid. The thin plasma column, a few meters in length and less than a centimeter in diameter, serves as a line source of neutrons. Test samples are located within or just behind the plasma tube, at a radius of 1-2 cm from the axis. The plasma is heated by an axially-directed powerful long-wavelength laser beam. The plasma is confined radially in the intense magnetic field supplied by a pulsed solenoid surrounding the plasma tube. The facility is pulsed many times a second to achieve a high time-averaged neutron flux on the test samples. Based on component performance achievable in the near term (e.g., magnetic field, laser pulse energy) and assuming classical physical processes, it appears that average fluxes of 10 13 to 10 14 neutrons/cm 2 -sec can be achieved in such a device. The most severe technical problems in such a facility appear to be rapid pulsing design and lifetime of some electrical and laser components

Neutronics of pulsed spallation neutron sources

International Nuclear Information System (INIS)

Watanabe, Noboru

2003-01-01

Various topics and issues on the neutronics of pulsed spallation neutron sources, mainly for neutron scattering experiments, are reviewed to give a wide circle of readers a better understanding of these sources in order to achieve a high neutronic performance. Starting from what neutrons are needed, what the spallation reaction is and how to produce slow-neutrons more efficiently, the outline of the target and moderator neutronics are explained. Various efforts with some new concepts or ideas have already been devoted to obtaining the highest possible slow-neutron intensity with desired pulse characteristics. This paper also reviews the recent progress of such efforts, mainly focused on moderator neutronics, since moderators are the final devices of a neutron source, which determine the source performance. Various governing parameters for neutron-pulse characteristics such as material issues, geometrical parameters (shape and dimensions), the target-moderator coupling scheme, the ortho-para-hydrogen ratio, poisoning, etc are discussed, aiming at a high performance pulsed spallation source

RF H-minus ion source development in China spallation neutron source

Science.gov (United States)

Chen, W.; Ouyang, H.; Xiao, Y.; Liu, S.; Lü, Y.; Cao, X.; Huang, T.; Xue, K.

2017-08-01

China Spallation Neutron Source (CSNS) phase-I project currently uses a Penning surface plasma H- ion source, which has a life time of several weeks with occasional sparks between high voltage electrodes. To extend the life time of the ion source and prepare for the CSNS phase-II, we are trying to develop a RF negative hydrogen ion source with external antenna. The configuration of the source is similar to the DESY external antenna ion source and SNS ion source. However several changes are made to improve the stability and the life time. Firstly, Si3N4 ceramic with high thermal shock resistance, and high thermal conductivity is used for plasma chamber, which can endure an average power of 2000W. Secondly, the water-cooled antenna is brazed on the chamber to improve the energy efficiency. Thirdly, cesium is injected directly to the plasma chamber if necessary, to simplify the design of the converter and the extraction. Area of stainless steel exposed to plasma is minimized to reduce the sputtering and degassing. Instead Mo, Ta, and Pt coated materials are used to face the plasma, which makes the self-cleaning of the source possible.

Neutronics of pulsed spallation neutron sources

CERN Document Server

Watanabe, N

2003-01-01

Various topics and issues on the neutronics of pulsed spallation neutron sources, mainly for neutron scattering experiments, are reviewed to give a wide circle of readers a better understanding of these sources in order to achieve a high neutronic performance. Starting from what neutrons are needed, what the spallation reaction is and how to produce slow-neutrons more efficiently, the outline of the target and moderator neutronics are explained. Various efforts with some new concepts or ideas have already been devoted to obtaining the highest possible slow-neutron intensity with desired pulse characteristics. This paper also reviews the recent progress of such efforts, mainly focused on moderator neutronics, since moderators are the final devices of a neutron source, which determine the source performance. Various governing parameters for neutron-pulse characteristics such as material issues, geometrical parameters (shape and dimensions), the target-moderator coupling scheme, the ortho-para-hydrogen ratio, po...

High Brightness Neutron Source for Radiography. Final report

International Nuclear Information System (INIS)

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

2008-01-01

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

Design of a linear neutron source

International Nuclear Information System (INIS)

Buzarbaruah, N.; Dutta, N.J.; Bhardwaz, J.K.; Mohanty, S.R.

2015-01-01

Highlights: • This paper reports the design of a linear neutron source based on inertial electrostatic confinement fusion scheme. • The voltage and current that is to be applied to the grid is computed theoretically. • Neutron production rate is theoretically estimated and found to be of the order of 10 7 –10 8 neutrons/s. • Electric potential distribution and ion trajectories are studied using SIMION code. • Optimized condition for the inner grid transparency has been found out. - Abstract: In this paper, we present the design of a linear neutron source based on the concept of inertial electrostatic confinement fusion. The source mainly comprises of a concentric coaxial cylindrical grid assembly housed inside a double walled cylindrical vacuum chamber, a gas injection system, a high voltage feedthrough and a high voltage negative polarity power supply. The inner grid will be kept at a high negative potential with respect to the outer grid that will be grounded. The effect of grid transparency on electric potential distribution and ion trajectories has been studied using SIMION. A diffuse deuterium plasma will be initially created by making filament discharge and subsequently, on application of high negative voltage to the inner grid, deuterons will be accelerated towards the axis of the device. These deuterons will oscillate in the negative potential and consequently fuse in between the grids to produce neutrons. This source is expected to produce 10 7 –10 8 neutrons/s. The proposed linear neutron source will be operated both in the continuous and pulse modes and it will be utilized for a few near term applications namely fusion reactor material studies and explosive detection

An accelerated beam-plasma neutron/proton source and early application of a fusion plasma

International Nuclear Information System (INIS)

Ohnishi, M.; Yoshikawa, K.; Yamamoto, Y.; Hoshino, C.; Masuda, K.; Miley, G.; Jurczyk, B.; Stubbers, R.; Gu, Y.

1999-01-01

We measured the number of the neutrons and protons produced by D-D reactions in an accelerated beam-plasma fusion and curried out the numerical simulations. The linear dependence of the neutron yield on a discharge current indicates that the fusion reactions occur between the background gas and the fast particles. i.e. charge exchanged neutrals and accelerated ions. The neutron yield divided by (fusion cross section x ion current x neutral gas pressure) still possesses the dependence of the 1.2 power of discharge voltage. which shows the fusion reactions are affected by the electrostatic potential built-up in the center. The measured proton birth profiles suggest the existence of a double potential well, which is supported by the numerical simulations. (author)

Design considerations for neutron activation and neutron source strength monitors for ITER

International Nuclear Information System (INIS)

Barnes, C.W.; Jassby, D.L.; LeMunyan, G.; Roquemore, A.L.

1997-01-01

The International Thermonuclear Experimental Reactor will require highly accurate measurements of fusion power production in time, space, and energy. Spectrometers in the neutron camera could do it all, but experience has taught us that multiple methods with redundancy and complementary uncertainties are needed. Previously, conceptual designs have been presented for time-integrated neutron activation and time-dependent neutron source strength monitors, both of which will be important parts of the integrated suite of neutron diagnostics for this purpose. The primary goals of the neutron activation system are: to maintain a robust relative measure of fusion energy production with stability and wide dynamic range; to enable an accurate absolute calibration of fusion power using neutronic techniques as successfully demonstrated on JET and TFTR; and to provide a flexible system for materials testing. The greatest difficulty is that the irradiation locations need to be close to plasma with a wide field of view. The routing of the pneumatic system is difficult because of minimum radius of curvature requirements and because of the careful need for containment of the tritium and activated air. The neutron source strength system needs to provide real-time source strength vs. time with ∼1 ms resolution and wide dynamic range in a robust and reliable manner with the capability to be absolutely calibrated by in-situ neutron sources as done on TFTR, JT-60U, and JET. In this paper a more detailed look at the expected neutron flux field around ITER is folded into a more complete design of the fission chamber system

Pulsed neutron generators based on plasma focus devices of low energy

International Nuclear Information System (INIS)

Silva, Patricio; Moreno, Jose; Soto, Leopoldo

2003-01-01

The plasma focus is a pulsed neutron source especially suited for applications because it reduces the danger of contamination of conventional isotopic radioactive sources. As first stage of a program to design a repetitive pulsed neutron generator for industrial applications we constructed two very small plasma focus operating at an energy level of the order of a) tens of joules (PF-50J, 160nF capacitor bank, 20-35 kV, 32-100J, ∼150ns first quarter of period) and b) hundred of joules (PF-400J, 880nF, 20-35kV, 176-539J, ∼300ns first quarter of period). In this article we present results related to design and construction of these small plasma foci (PF-50J and PF-400J). Neutron yield vs. deuterium. pressure has been obtained, a maximum emission of the order of 7x10 4 and 10 6 neutrons per shot has been measured in the PF-50J and PF-400J respectively (author)

Calibration of a detector by activation with a continuous neutron source used as a transfer standard for measuring pulsed neutron beams

International Nuclear Information System (INIS)

Moreno, Jose; Silva, Patricio; Birstein, Lipo; Soto, Leopoldo

2002-01-01

This paper presents a method for calibrating activation detectors. These detectors will be used as transfer standard in measuring neutron fluxes produced by pulsed plasma sources. A standard neutron source is used as a secondary standard. The activation detector is being shielded in order to substantially reduce detection of gamma emission coming from the source. The detector's calibration factor is obtained by considering also the standard neutron source as a free source of gamma radiation so that the measurements can be done without quickly withdrawing the neutron source as it is usually done. This will substantially simplify the traditionally established method (JM)

Neutron cooling and cold-neutron sources (1962); Refroidissement des neutrons et sources de neutrons froids (1962)

Energy Technology Data Exchange (ETDEWEB)

Jacrot, B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1962-07-01

Intense cold-neutron sources are useful in studying solids by the inelastic scattering of neutrons. The paper presents a general survey covering the following aspects: a) theoretical considerations put forward by various authors regarding thermalization processes at very low temperatures; b) the experiments that have been carried out in numerous laboratories with a view to comparing the different moderators that can be used; c) the cold neutron sources that have actually been produced in reactors up to the present time, and the results obtained with them. (author) [French] Des sources intenses de neutrons froids sont utiles pour l'etude des solides par diffusion inelastique des neutrons. On presente une revue d'ensemble: a) des considerations theoriques faites par divers auteurs sur les processus de thermalisation a tres basse temperature; b) des experiences faites dans de nombreux laboratoires pour comparer les divers moderateurs possibles; c) des sources de neutrons froids effectivement realisees dans des piles a ce jour, et des resultats obtenus avec ces sources. (auteur)

Surface plasma source with saddle antenna radio frequency plasma generator.

Science.gov (United States)

Dudnikov, V; Johnson, R P; Murray, S; Pennisi, T; Piller, C; Santana, M; Stockli, M; Welton, R

2012-02-01

A prototype RF H(-) surface plasma source (SPS) with saddle (SA) RF antenna is developed which will provide better power efficiency for high pulsed and average current, higher brightness with longer lifetime and higher reliability. Several versions of new plasma generators with small AlN discharge chambers and different antennas and magnetic field configurations were tested in the plasma source test stand. A prototype SA SPS was installed in the Spallation Neutron Source (SNS) ion source test stand with a larger, normal-sized SNS AlN chamber that achieved unanalyzed peak currents of up to 67 mA with an apparent efficiency up to 1.6 mA∕kW. Control experiments with H(-) beam produced by SNS SPS with internal and external antennas were conducted. A new version of the RF triggering plasma gun has been designed. A saddle antenna SPS with water cooling is fabricated for high duty factor testing.

Neutron source

International Nuclear Information System (INIS)

Cason, J.L. Jr.; Shaw, C.B.

1975-01-01

A neutron source which is particularly useful for neutron radiography consists of a vessel containing a moderating media of relatively low moderating ratio, a flux trap including a moderating media of relatively high moderating ratio at the center of the vessel, a shell of depleted uranium dioxide surrounding the moderating media of relatively high moderating ratio, a plurality of guide tubes each containing a movable source of neutrons surrounding the flux trap, a neutron shield surrounding one part of each guide tube, and at least one collimator extending from the flux trap to the exterior of the neutron source. The shell of depleted uranium dioxide has a window provided with depleted uranium dioxide shutters for each collimator. Reflectors are provided above and below the flux trap and on the guide tubes away from the flux trap

Beryllium neutron activation detector for pulsed DD fusion sources

International Nuclear Information System (INIS)

Talebitaher, A.; Springham, S.V.; Rawat, R.S.; Lee, P.

2011-01-01

A compact fast neutron detector based on beryllium activation has been developed to perform accurate neutron fluence measurements on pulsed DD fusion sources. It is especially well suited to moderate repetition-rate ( 9 Be(n,α) 6 He cross-section, energy calibration of the proportional counters, and numerical simulations of neutron interactions and beta-particle paths using MCNP5. The response function R(E n ) is determined over the neutron energy range 2-4 MeV. The count rate capability of the detector has been studied and the corrections required for high neutron fluence measurements are discussed. For pulsed DD neutron fluencies >3×10 4 cm -2 , the statistical uncertainty in the fluence measurement is better than 1%. A small plasma focus device has been employed as a pulsed neutron source to test two of these new detectors, and their responses are found to be practically identical. Also the level of interfering activation is found to be sufficiently low as to be negligible.

Spallation neutron sources

International Nuclear Information System (INIS)

Fraser, J.S.; Bartholomew, G.A.

1983-01-01

The principles and theory of spallation neutron sources are outlined and a comparison is given with other types of neutron source. A summary of the available accelerator types for spallation neutron sources and their advantages and disadvantages is presented. Suitable target materials are discussed for specific applications, and typical target assemblies shown. (U.K.)

Palm top plasma focus device as a portable pulsed neutron source

International Nuclear Information System (INIS)

Rout, R. K.; Niranjan, Ram; Srivastava, R.; Rawool, A. M.; Kaushik, T. C.; Gupta, Satish C.; Mishra, P.

2013-01-01

Development of a palm top plasma focus device generating (5.2 ± 0.8) × 10 4 neutrons/pulse into 4π steradians with a pulse width of 15 ± 3 ns is reported for the first time. The weight of the system is less than 1.5 kg. The system comprises a compact capacitor bank, a triggered open air spark gap switch, and a sealed type miniature plasma focus tube. The setup is around 14 cm in diameter and 12.5 cm in length. The energy driver for the unit is a capacitor bank of four cylindrical commercially available electrolytic capacitors. Each capacitor is of 2 μF capacity, 4.5 cm in diameter, and 9.8 cm in length. The cost of each capacitor is less than US$ 10. The internal diameter and the effective length of the plasma focus unit are 2.9 cm and 5 cm, respectively. A DC to DC converter power supply powered by two rechargeable batteries charges the capacitor bank to the desired voltage and also provides a trigger pulse of −15 kV to the spark gap. The maximum energy of operation of the device is 100 J (8 μF, 5 kV, 59 kA) with deuterium gas filling pressure of 3 mbar. The neutrons have also been produced at energy as low as 36 J (3 kV) of operation. The neutron diagnostics are carried out with a bank of 3 He detectors and with a plastic scintillator detector. The device is portable, reusable, and can be operated for multiple shots with a single gas filling.

Measurement of angular distribution of neutrons emitted from plasma focus using NTD

International Nuclear Information System (INIS)

Antanasijevic, R.; Maric, Z.; Banjanac, R.; Dragic, A.; Stanojevic, J.; Dordevic, D.; Joksimovic, D.; Udovicic, V.; Vukovic, J.

1999-01-01

Mica detectors together with thick uranium foils were used for detection and angular distribution measurement of the neutrons emitted from the d-plasma focus (DPF). The distance between detectors and plasma pinch was 4 cm. For reason of detector protection from the thermal shock, they were covered with the mica layer of 1 mm thickness. Annealing of the detectors were measured after the irradiation with neutrons from an Am-Be source and treated with thermal shock H-plasma focus (HPF). Geometry of detectors in both experiments was the same

Measurement of angular distribution of neutrons emitted from plasma focus using NTD

Energy Technology Data Exchange (ETDEWEB)

Antanasijevic, R.; Maric, Z.; Banjanac, R.; Dragic, A.; Stanojevic, J.; Dordevic, D.; Joksimovic, D.; Udovicic, V.; Vukovic, J

1999-06-01

Mica detectors together with thick uranium foils were used for detection and angular distribution measurement of the neutrons emitted from the d-plasma focus (DPF). The distance between detectors and plasma pinch was 4 cm. For reason of detector protection from the thermal shock, they were covered with the mica layer of 1 mm thickness. Annealing of the detectors were measured after the irradiation with neutrons from an Am-Be source and treated with thermal shock H-plasma focus (HPF). Geometry of detectors in both experiments was the same.

Measurement of angular distribution of neutrons emitted from plasma focus using NTD

CERN Document Server

Antanasijevic, R; Banjanac, R; Dragic, A; Stanojevic, J; Dordevic, D; Joksimovic, D; Udovicic, V; Vukovic, J

1999-01-01

Mica detectors together with thick uranium foils were used for detection and angular distribution measurement of the neutrons emitted from the d-plasma focus (DPF). The distance between detectors and plasma pinch was 4 cm. For reason of detector protection from the thermal shock, they were covered with the mica layer of 1 mm thickness. Annealing of the detectors were measured after the irradiation with neutrons from an Am-Be source and treated with thermal shock H-plasma focus (HPF). Geometry of detectors in both experiments was the same.

Pulsed neutron sources for epithermal neutrons

International Nuclear Information System (INIS)

Windsor, C.G.

1978-01-01

It is shown how accelerator based neutron sources, giving a fast neutron pulse of short duration compared to the neutron moderation time, promise to open up a new field of epithermal neutron scattering. The three principal methods of fast neutron production: electrons, protons and fission boosters will be compared. Pulsed reactors are less suitable for epithermal neutrons and will only be briefly mentioned. The design principle of the target producing fast neutrons, the moderator and reflector to slow them down to epithermal energies, and the cell with its beam tubes and shielding will all be described with examples taken from the new Harwell electron linac to be commissioned in 1978. A general comparison of pulsed neutron performance with reactors is fraught with difficulties but has been attempted. Calculation of the new pulsed source fluxes and pulse widths is now being performed but we have taken the practical course of basing all comparisons on extrapolations from measurements on the old 1958 Harwell electron linac. Comparisons for time-of-flight and crystal monochromator experiments show reactors to be at their best at long wavelengths, at coarse resolution, and for experiments needing a specific incident wavelength. Even existing pulsed sources are shown to compete with the high flux reactors in experiments where the hot neutron flux and the time-of-flight methods can be best exploited. The sources under construction can open a new field of inelastic neutron scattering based on energy transfer up to an electron volt and beyond

Reactor Neutron Sources

International Nuclear Information System (INIS)

Aksenov, V.L.

1994-01-01

The present status and the prospects for development of reactor neutron sources for neutron scattering research in the world are considered. The fields of application of neutron scattering relative to synchrotron radiation, the creation stages of reactors (steady state and pulsed) and their position in comparison with spallation neutron sources at present and in the foreseen future are discussed. (author). 15 refs.; 8 figs.; 3 tabs

Neutron sources and applications

Energy Technology Data Exchange (ETDEWEB)

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

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.

Neutron sources and applications

International Nuclear Information System (INIS)

Price, D.L.; Rush, J.J.

1994-01-01

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

Elaboration of the principal design characteristics of the magnetic system for the hydrogen prototype of the neutron source

International Nuclear Information System (INIS)

Aleksandrov, A.S.; Gorbovskij, A.I.; Mishagin, V.V.

1994-01-01

The paper reviews designs of magnets and vacuum system of the Hydrogen Prototype of the Neutron Source. An idea of this neutron source is based on the use of neutral-beam-driven plasma in an axisymmetric magnetic mirror to generate high flux D-T neutrons. Preliminary evaluations have shown that such a source has several potential advantages when is used for fusion material and component tests. The Hydrogen Prototype is essentially full scale model of the source but operated with a hydrogen plasma. 10 refs.; 6 figs.; 1 tab

Accelerator based continuous neutron source.

CERN Document Server

Shapiro, S M; Ruggiero, A G

2003-01-01

Until the last decade, most neutron experiments have been performed at steady-state, reactor-based sources. Recently, however, pulsed spallation sources have been shown to be very useful in a wide range of neutron studies. A major review of neutron sources in the US was conducted by a committee chaired by Nobel laureate Prof. W. Kohn: ''Neutron Sources for America's Future-BESAC Panel on Neutron Sources 1/93''. This distinguished panel concluded that steady state and pulsed sources are complementary and that the nation has need for both to maintain a balanced neutron research program. The report recommended that both a new reactor and a spallation source be built. This complementarity is recognized worldwide. The conclusion of this report is that a new continuous neutron source is needed for the second decade of the 20 year plan to replace aging US research reactors and close the US neutron gap. it is based on spallation production of neutrons using a high power continuous superconducting linac to generate pr...

Lunar neutron source function

International Nuclear Information System (INIS)

Kornblum, J.J.

1974-01-01

The search for a quantitative neutron source function for the lunar surface region is justified because it contributes to our understanding of the history of the lunar surface and of nuclear process occurring on the moon since its formation. A knowledge of the neutron source function and neutron flux distribution is important for the interpretation of many experimental measurements. This dissertation uses the available pertinent experimental measurements together with theoretical calculations to obtain an estimate of the lunar neutron source function below 15 MeV. Based upon reasonable assumptions a lunar neutron source function having adjustable parameters is assumed for neutrons below 15 MeV. The lunar neutron source function is composed of several components resulting from the action of cosmic rays with lunar material. A comparison with previous neutron calculations is made and significant differences are discussed. Application of the results to the problem of lunar soil histories is examined using the statistical model for soil development proposed by Fireman. The conclusion is drawn that the moon is losing mass

Properties of neutron sources

International Nuclear Information System (INIS)

1987-03-01

The Conference presentations were divided into sessions devoted to the following topics: white neutron sources, primarily pulsed (6 papers); fast neutron fields (5 papers); Californium-252 prompt fission neutron spectra (14 papers); monoenergetic sources and filtered beams (11 papers); 14 MeV neutron sources (10 papers); selected special application (one paper); and a general interest session (4 papers). Individual abstracts were prepared separately for the papers

Spallation Neutron Source (SNS)

Data.gov (United States)

Federal Laboratory Consortium — The SNS at Oak Ridge National Laboratory is a next-generation spallation neutron source for neutron scattering that is currently the most powerful neutron source in...

Effects of gas chamber geometry and gas flow on the neutron production in a fast plasma focus neutron source

International Nuclear Information System (INIS)

Tarifeño-Saldivia, Ariel; Soto, Leopoldo

2014-01-01

This work reports that gas chamber geometry and gas flow management substantially affect the neutron production of a repetitive fast plasma focus. The gas flow rate is the most sensitive parameter. An appropriate design of the gas chamber combined with a suitable flow-rate management can lead to improvements in the neutron production of one order of magnitude working in a fast repetitive mode. (paper)

Spallation neutrons pulsed sources

International Nuclear Information System (INIS)

Carpenter, J.

1996-01-01

This article describes the range of scientific applications which can use these pulsed neutrons sources: Studies on super fluids, measures to verify the crawling model for the polymers diffusion; these sources are also useful to study the neutron disintegration, the ultra cold neutrons. In certain applications which were not accessible by neutrons diffusion, for example, radiations damages, radionuclides production and activation analysis, the spallation sources find their use and their improvement will bring new possibilities. Among others contributions, one must notice the place at disposal of pulsed muons sources and neutrinos sources. (N.C.). 3 figs

The desing study of high voltage plasma focus for a large fluence neutron source by using a water capacitor bank

International Nuclear Information System (INIS)

Ueno, Isao; Kobata, Tadasuke

1983-01-01

A new possibility for high intensity neutron source (HINS) would be opened by the plasma focus device if we have a high voltage capacitor bank. A scaling law of neutron yield for D-T gas discharge in plasma focus device is obtained after Imshennik, Filippov and Filippova. The resulting scaling law shows the realizability of the D-T HINS by the use of plasma focus, provided that the device is operated under a high voltage condition. Until now, it has been difficult to construct the high voltage capacitor bank of long life, for example with V 0 =300kV, C 0 =200μF and L 0 --5nH necessary in the level of HINS. It becomes possible to design this capacitor bank by using the coaxial water capacitor which has been developed for the electron and ion beam accelerator. The size of a capacitor designed for V 0 =300kV, C 0 =1μF is phi5m x 22m. Two hundred capacitors are used in parallel in order to get the 200μF. (author)

Neutron spectra produced by moderating an isotopic neutron source

International Nuclear Information System (INIS)

Carrillo Nunnez, Aureliano; Vega Carrillo, Hector Rene

2001-01-01

A Monte Carlo study has been carried out to determine the neutron spectra produced by an isotopic neutron source inserted in moderating media. Most devices used for radiation protection have a response strongly dependent on neutron energy. ISO recommends several neutron sources and monoenergetic neutron radiations, but actual working situations have broad spectral neutron distributions extending from thermal to MeV energies, for instance, near nuclear power plants, medical applications accelerators and cosmic neutrons. To improve the evaluation of the dosimetric quantities, is recommended to calibrate the radiation protection devices in neutron spectra which are nearly like those met in practice. In order to complete the range of neutron calibrating sources, it seems useful to develop several wide spectral distributions representative of typical spectra down to thermal energies. The aim of this investigation was to use an isotopic neutron source in different moderating media to reproduce some of the neutron fields found in practice. MCNP code has been used during calculations, in these a 239PuBe neutron source was inserted in H2O, D2O and polyethylene moderators. Moderators were modeled as spheres and cylinders of different sizes. In the case of cylindrical geometry the anisotropy of resulting neutron spectra was calculated from 0 to 2 . From neutron spectra dosimetric features were calculated. MCNP calculations were validated by measuring the neutron spectra of a 239PuBe neutron source inserted in a H2O cylindrical moderator. The measurements were carried out with a multisphere neutron spectrometer with a 6LiI(Eu) scintillator. From the measurements the neutron spectrum was unfolded using the BUNKIUT code and the UTA4 response matrix. Some of the moderators with the source produce a neutron spectrum close to spectra found in actual applications, then can be used during the calibration of radiation protection devices

The secondary neutron sources for generation of particular neutron fluxes

International Nuclear Information System (INIS)

Tracz, G.

2007-07-01

The foregoing paper presents the doctor's thesis entitled '' The secondary neutron sources for generation of particular neutron fluxes ''. Two secondary neutron sources have been designed, which exploit already existing primary sources emitting neutrons of energies different from the desired ones. The first source is devoted to boron-neutron capture therapy (BNCT). The research reactor MARIA at the Institute of Atomic Energy in Swierk (Poland) is the primary source of the reactor thermal neutrons, while the secondary source should supply epithermal neutrons. The other secondary source is the pulsed source of thermal neutrons that uses fast 14 MeV neutrons from a pulsed generator at the Institute of Nuclear Physics PAN in Krakow (Poland). The physical problems to be solved in the two mentioned cases are different. Namely, in order to devise the BNCT source the initial energy of particles ought to be increased, whilst in the other case the fast neutrons have to be moderated. Slowing down of neutrons is relatively easy since these particles lose energy when they scatter in media; the most effective moderators are the materials which contain light elements (mostly hydrogen). In order to increase the energy of neutrons from thermal to epithermal (the BNCT case) the so-called neutron converter should be exploited. It contains a fissile material, 235 U. The thermal neutrons from the reactor cause fission of uranium and fast neutrons are emitted from the converter. Then fissile neutrons of energy of a few MeV are slowed down to the required epithermal energy range. The design of both secondary sources have been conducted by means of Monte Carlo simulations, which have been carried out using the MCNP code. In the case of the secondary pulsed thermal neutron source, some of the calculated results have been verified experimentally. (author)

Absolute calibration of TFTR neutron detectors for D-T plasma operation

International Nuclear Information System (INIS)

Jassby, D.L.; Johnson, L.C.; Roquemore, A.L.; Strachan, J.D.; Johnson, D.W.; Medley, S.S.; Young, K.M.

1995-03-01

The two most sensitive TFTR fission-chamber detectors were absolutely calibrated in situ by a D-T neutron generator (∼5 x 10 7 n/s) rotated once around the torus in each direction, with data taken at about 45 positions. The combined uncertainty for determining fusion neutron rates, including the uncertainty in the total neutron generator output (±9%), counting statistics, the effect of coil coolant, detector stability, cross-calibration to the current mode or log Campbell mode and to other fission chambers, and plasma position variation, is about ±13%. The NE-451 (ZnS) scintillators and 4 He proportional counters that view the plasma in up to 10 collimated sightlines were calibrated by scanning. the neutron generator radially and toroidally in the horizontal midplane across the flight tubes of 7 cm diameter. Spatial integration of the detector responses using the calibrated signal per unit chord-integrated neutron emission gives the global neutron source strength with an overall uncertainty of ±14% for the scintillators and ±15% for the 4 He counters

Development of a High Fluence Neutron Source for Nondestructive Characterization of Nuclear Waste

International Nuclear Information System (INIS)

Pickrell, Mark M.

1999-01-01

We are addressing the need to measure nuclear wastes, residues, and spent fuel in order to process these for final disposition. For example, TRU wastes destined for the WIPP must satisfy extensive characterization criteria outlined in the Waste Acceptance Criteria, the Quality Assurance Program Plan, and the Performance Demonstration Plan. Similar requirements exist for spent fuel and residues. At present, no nondestructive assay (NDA) instrumentation is capable of satisfying all of the PDP test cycles (particularly for Remote-Handled TRU waste). One of the primary methods for waste assay is by active neutron interrogation. The objective of this project is to improve the capability of all active neutron systems by providing a higher intensity neutron source (by about a factor of 1,000) for essentially the same cost, power, and space requirements as existing systems. This high intensity neutron source is an electrostatically confined (IEC) plasma device. The IEC is a symmetric sphere that was originally developed in the 1960s as a possible fusion reactor. It operates as DT neutron generator. Although it is not likely that this device will scale to fusion reactor levels, previous experiments1 have demonstrated a neutron yield of 2 x 1010 neutrons/second on a table-top device that can be powered from ordinary laboratory circuits (9 kilowatts). Subsequently, the IEC physics has been extensively studied at the University of Illinois and other locations. We have established theoretically the basis for scaling the output up to 1 x 1011 neutrons/second. In addition, IEC devices have run for cumulative times approaching 10,000 hours, which is essential for practical application to NDA. They have been operated in pulsed and continuous mode. The essential features of the IEC plasma neutron source, compared to existing sources of the same cost, size and power consumption, are: Table 1: Present and Target Operating Parameters for Small Neutron Generators Parameter Present IEC

Neutron Imaging at Compact Accelerator-Driven Neutron Sources in Japan

Directory of Open Access Journals (Sweden)

Yoshiaki Kiyanagi

2018-03-01

Full Text Available Neutron imaging has been recognized to be very useful to investigate inside of materials and products that cannot be seen by X-ray. New imaging methods using the pulsed structure of neutron sources based on accelerators has been developed also at compact accelerator-driven neutron sources and opened new application fields in neutron imaging. The world’s first dedicated imaging instrument at pulsed neutron sources was constructed at J-PARC in Japan owing to the development of such new methods. Then, usefulness of the compact accelerator-driven neutron sources in neutron science was recognized and such facilities were newly constructed in Japan. Now, existing and new sources have been used for neutron imaging. Traditional imaging and newly developed pulsed neutron imaging such as Bragg edge transmission have been applied to various fields by using compact and large neutron facilities. Here, compact accelerator-driven neutron sources used for imaging in Japan are introduced and some of their activities are presented.

US-Japan IEC Workshop on Small Plasma and Accelerator Neutron Sources. Final report

International Nuclear Information System (INIS)

Miley, George H.

2008-01-01

The history of IEC development will be briefly described, and some speculation about future directions will be offered. The origin of IEC is due to the brilliance of Phil Farnsworth, inventor of electronic TV in the US. Early experiments were pioneered in the late 1960s by Robert Hirsch who later became head of the DOE fusion program. At that time studies of IEC physics quickly followed at the University of Illinois and at Penn State University. However, despite many successes in this early work, IEC research died as DOE funding stopped in the mid 1980s. In the early 90's, R. W. Bussard of EMC revived work with a new major project based on a magnetic assisted IEC. While doing supportive studies for that project, G. Miley proposed a grided 'STAR mode' IEC as a neutron source for NAA. This concept was later used commercially by Daimler-Benz in Germany to analysis impurities in incoming ores. This represented a first practical application of the IEC. During this period other research groups at LANL, U of Wisconsin and Kyoto University entered IEC research with innovative new concepts and approaches to IEC physics and applications. Much of this work is documented in the present and in past US-Japan Workshops. At present we stand on the threshold of a new area of IEC applications as neutron source, for isotope production, and as a plasma source. These applications provide a way to continue IEC understanding and technology development with the ultimate goal being a fusion power plant. Indeed, a distinguishing feature of the IEC vs. other fusion confinement approaches is the unique opportunity for 'spin off' applications along the way to a power producing plant.

The Los Alamos Neutron Science Center Spallation Neutron Sources

International Nuclear Information System (INIS)

Nowicki, Suzanne F.; Wender, Stephen A.; Mocko, Michael

2017-01-01

The Los Alamos Neutron Science Center (LANSCE) provides the scientific community with intense sources of neutrons, which can be used to perform experiments supporting civilian and national security research. These measurements include nuclear physics experiments for the defense program, basic science, and the radiation effect programs. This paper focuses on the radiation effects program, which involves mostly accelerated testing of semiconductor parts. When cosmic rays strike the earth's atmosphere, they cause nuclear reactions with elements in the air and produce a wide range of energetic particles. Because neutrons are uncharged, they can reach aircraft altitudes and sea level. These neutrons are thought to be the most important threat to semiconductor devices and integrated circuits. The best way to determine the failure rate due to these neutrons is to measure the failure rate in a neutron source that has the same spectrum as those produced by cosmic rays. Los Alamos has a high-energy and a low-energy neutron source for semiconductor testing. Both are driven by the 800-MeV proton beam from the LANSCE accelerator. The high-energy neutron source at the Weapons Neutron Research (WNR) facility uses a bare target that is designed to produce fast neutrons with energies from 100 keV to almost 800 MeV. The measured neutron energy distribution from WNR is very similar to that of the cosmic-ray-induced neutrons in the atmosphere. However, the flux provided at the WNR facility is typically 5×107 times more intense than the flux of the cosmic-ray-induced neutrons. This intense neutron flux allows testing at greatly accelerated rates. An irradiation test of less than an hour is equivalent to many years of neutron exposure due to cosmic-ray neutrons. The low-energy neutron source is located at the Lujan Neutron Scattering Center. It is based on a moderated source that provides useful neutrons from subthermal energies to ~100 keV. The characteristics of these sources

The Los Alamos Neutron Science Center Spallation Neutron Sources

Science.gov (United States)

Nowicki, Suzanne F.; Wender, Stephen A.; Mocko, Michael

The Los Alamos Neutron Science Center (LANSCE) provides the scientific community with intense sources of neutrons, which can be used to perform experiments supporting civilian and national security research. These measurements include nuclear physics experiments for the defense program, basic science, and the radiation effect programs. This paper focuses on the radiation effects program, which involves mostly accelerated testing of semiconductor parts. When cosmic rays strike the earth's atmosphere, they cause nuclear reactions with elements in the air and produce a wide range of energetic particles. Because neutrons are uncharged, they can reach aircraft altitudes and sea level. These neutrons are thought to be the most important threat to semiconductor devices and integrated circuits. The best way to determine the failure rate due to these neutrons is to measure the failure rate in a neutron source that has the same spectrum as those produced by cosmic rays. Los Alamos has a high-energy and a low-energy neutron source for semiconductor testing. Both are driven by the 800-MeV proton beam from the LANSCE accelerator. The high-energy neutron source at the Weapons Neutron Research (WNR) facility uses a bare target that is designed to produce fast neutrons with energies from 100 keV to almost 800 MeV. The measured neutron energy distribution from WNR is very similar to that of the cosmic-ray-induced neutrons in the atmosphere. However, the flux provided at the WNR facility is typically 5×107 times more intense than the flux of the cosmic-ray-induced neutrons. This intense neutron flux allows testing at greatly accelerated rates. An irradiation test of less than an hour is equivalent to many years of neutron exposure due to cosmic-ray neutrons. The low-energy neutron source is located at the Lujan Neutron Scattering Center. It is based on a moderated source that provides useful neutrons from subthermal energies to ∼100 keV. The characteristics of these sources, and

New neutron imaging using pulsed sources. Characteristics of a pulsed neutron source and principle of pulsed neutron imaging

International Nuclear Information System (INIS)

Kiyanagi, Yoshiaki

2012-01-01

Neutron beam is one of important tools to obtain the transmission image of an object. Until now, steady state neutron sources such as reactors are mainly used for this imaging purpose. Recently, it has been demonstrated that pulsed neutron imaging based on accelerator neutron sources can provide a real-space distribution of physical information of materials such as crystallographic structure, element, temperature, hydrogen bound state, magnetic field and so on, by analyzing wavelength dependent transmission spectrum, which information cannot be observed or difficult to obtain with a traditional imaging method using steady state neutrons. Here, characteristics of the pulsed neutron source and principle of the pulsed neutron imaging are explained as a basic concept of the new method. (author)

Helicon plasma generator-assisted surface conversion ion source for the production of H(-) ion beams at the Los Alamos Neutron Science Center.

Science.gov (United States)

Tarvainen, O; Rouleau, G; Keller, R; Geros, E; Stelzer, J; Ferris, J

2008-02-01

The converter-type negative ion source currently employed at the Los Alamos Neutron Science Center (LANSCE) is based on cesium enhanced surface production of H(-) ion beams in a filament-driven discharge. In this kind of an ion source the extracted H(-) beam current is limited by the achievable plasma density which depends primarily on the electron emission current from the filaments. The emission current can be increased by increasing the filament temperature but, unfortunately, this leads not only to shorter filament lifetime but also to an increase in metal evaporation from the filament, which deposits on the H(-) converter surface and degrades its performance. Therefore, we have started an ion source development project focused on replacing these thermionic cathodes (filaments) of the converter source by a helicon plasma generator capable of producing high-density hydrogen plasmas with low electron energy. In our studies which have so far shown that the plasma density of the surface conversion source can be increased significantly by exciting a helicon wave in the plasma, and we expect to improve the performance of the surface converter H(-) ion source in terms of beam brightness and time between services. The design of this new source and preliminary results are presented, along with a discussion of physical processes relevant for H(-) ion beam production with this novel design. Ultimately, we perceive this approach as an interim step towards our long-term goal, combining a helicon plasma generator with an SNS-type main discharge chamber, which will allow us to individually optimize the plasma properties of the plasma cathode (helicon) and H(-) production (main discharge) in order to further improve the brightness of extracted H(-) ion beams.

Helicon plasma generator-assisted surface conversion ion source for the production of H- ion beams at the Los Alamos Neutron Science Centera)

Science.gov (United States)

Tarvainen, O.; Rouleau, G.; Keller, R.; Geros, E.; Stelzer, J.; Ferris, J.

2008-02-01

The converter-type negative ion source currently employed at the Los Alamos Neutron Science Center (LANSCE) is based on cesium enhanced surface production of H- ion beams in a filament-driven discharge. In this kind of an ion source the extracted H- beam current is limited by the achievable plasma density which depends primarily on the electron emission current from the filaments. The emission current can be increased by increasing the filament temperature but, unfortunately, this leads not only to shorter filament lifetime but also to an increase in metal evaporation from the filament, which deposits on the H- converter surface and degrades its performance. Therefore, we have started an ion source development project focused on replacing these thermionic cathodes (filaments) of the converter source by a helicon plasma generator capable of producing high-density hydrogen plasmas with low electron energy. In our studies which have so far shown that the plasma density of the surface conversion source can be increased significantly by exciting a helicon wave in the plasma, and we expect to improve the performance of the surface converter H- ion source in terms of beam brightness and time between services. The design of this new source and preliminary results are presented, along with a discussion of physical processes relevant for H- ion beam production with this novel design. Ultimately, we perceive this approach as an interim step towards our long-term goal, combining a helicon plasma generator with an SNS-type main discharge chamber, which will allow us to individually optimize the plasma properties of the plasma cathode (helicon) and H- production (main discharge) in order to further improve the brightness of extracted H- ion beams.

Helicon plasma generator-assisted surface conversion ion source for the production of H- ion beams at the Los Alamos Neutron Science Center

International Nuclear Information System (INIS)

Tarvainen, O.; Rouleau, G.; Keller, R.; Geros, E.; Stelzer, J.; Ferris, J.

2008-01-01

The converter-type negative ion source currently employed at the Los Alamos Neutron Science Center (LANSCE) is based on cesium enhanced surface production of H - ion beams in a filament-driven discharge. In this kind of an ion source the extracted H - beam current is limited by the achievable plasma density which depends primarily on the electron emission current from the filaments. The emission current can be increased by increasing the filament temperature but, unfortunately, this leads not only to shorter filament lifetime but also to an increase in metal evaporation from the filament, which deposits on the H - converter surface and degrades its performance. Therefore, we have started an ion source development project focused on replacing these thermionic cathodes (filaments) of the converter source by a helicon plasma generator capable of producing high-density hydrogen plasmas with low electron energy. In our studies which have so far shown that the plasma density of the surface conversion source can be increased significantly by exciting a helicon wave in the plasma, and we expect to improve the performance of the surface converter H - ion source in terms of beam brightness and time between services. The design of this new source and preliminary results are presented, along with a discussion of physical processes relevant for H - ion beam production with this novel design. Ultimately, we perceive this approach as an interim step towards our long-term goal, combining a helicon plasma generator with an SNS-type main discharge chamber, which will allow us to individually optimize the plasma properties of the plasma cathode (helicon) and H - production (main discharge) in order to further improve the brightness of extracted H - ion beams

Sources of polarized neutrons

International Nuclear Information System (INIS)

Walter, L.

1983-01-01

Various sources of polarized neutrons are reviewed. Monoenergetic source produced with unpolarized or polarized beams, white sources of polarized neutrons, production by transmissions through polarized hydrogen targets and polarized thermal neutronsare discussed, with appropriate applications included. (U.K.)

Neutron emission in neutral beam heated KSTAR plasmas and its application to neutron radiography

Energy Technology Data Exchange (ETDEWEB)

Kwak, Jong-Gu, E-mail: jgkwak@nfri.re.kr; Kim, H.S.; Cheon, M.S.; Oh, S.T.; Lee, Y.S.; Terzolo, L.

2016-11-01

Highlights: • We measured the neutron emission from KSTAR plasmas quantitatively. • We confirmed that neutron emission is coming from neutral beam-plasma interactions. • The feasibility study shows that the fast neutron from KSTAR could be used for fast neutron radiography. - Abstract: The main mission of Korea Superconducting Tokamak Advanced Research (KSTAR) program is exploring the physics and technologies of high performance steady state Tokamak operation that are essential for ITER and fusion reactor. Since the successful first operation in 2008, the plasma performance is enhanced and duration of H-mode is extended to around 50 s which corresponds to a few times of current diffusion time and surpassing the current conventional Tokamak operation. In addition to long-pulse operation, the operational boundary of the H-mode discharge is further extended over MHD no-wall limit(β{sub N} ∼ 4) transiently and higher stored energy region is obtained by increased total heating power (∼6 MW) and plasma current (I{sub p} up to 1 MA for ∼10 s). Heating system consists of various mixtures (NB, ECH, LHCD, ICRF) but the major horse heating resource is the neutral beam(NB) of 100 keV with 4.5 MW and most of experiments are conducted with NB. So there is a lot of production of fast neutrons coming from via D(d,n){sup 3}He reaction and it is found that most of neutrons are coming from deuterium beam plasma interaction. Nominal neutron yield and the area of beam port is about 10{sup 13}–10{sup 14}/s and 1 m{sup 2} at the closest access position of the sample respectively and neutron emission could be modulated for application to the neutron radiography by varying NB power. This work reports on the results of quantitative analysis of neutron emission measurements and results are discussed in terms of beam-plasma interaction and plasma confinement. It also includes the feasibility study of neutron radiography using KSTAR.

Thermal neutron source study

International Nuclear Information System (INIS)

Holden, T.M.

1983-05-01

The value of intense neutron beams for condensed matter research is discussed with emphasis on the complementary nature of steady state and pulsed neutron sources. A large body of information on neutron sources, both existing and planned, is then summarized under four major headings: fission reactors, electron accelerators with heavy metal targets, pulsed spallation sources and 'steady state' spallation sources. Although the cost of a spallation source is expected to exceed that of a fission reactor of the same flux by a factor of two, there are significant advantages for a spallation device such as the proposed Electronuclear Materials Test Facility (EMTF)

Neutron PSDs for the next generation of spallation neutron sources

CERN Document Server

Eijk, C W

2002-01-01

A review of R and D for neutron PSDs to be used at anticipated new spallation neutron sources: the Time-of-Flight system facility, European Spallation Source, Spallation Neutron Source and Neutron Arena, is presented. The gas-filled detectors, scintillation detectors and hybrid systems are emphasized.

Status of spallation neutron source

Energy Technology Data Exchange (ETDEWEB)

Oyama, Yukio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1997-03-01

Existing and planned facilities using proton accelerator driven spallation neutron source are reviewed. These include new project of neutron science proposed from Japan Atomic Energy Research Institute. The present status of facility requirement and accelerator technology leads us to new era of neutron science such as neutron scattering research and nuclear transmutation study using very intense neutron source. (author)

Radiography using californium-252 neutron sources

International Nuclear Information System (INIS)

Ray, J.W.

1975-01-01

The current status in the technology of neutron radiography using californium-252 neutron sources is summarized. Major emphasis is on thermal neutron radiography since it has the widest potential applicability at the present time. Attention is given to four major factors which affect the quality and useability of thermal neutron radiography: source neutron thermalization, neutron beam extraction geometry, neutron collimator dimensions, and neutron imaging methods. Each of these factors has a major effect on the quality of the radiographs which are obtained from a californium source neutron radiography system and the exposure times required to obtain the radiographs; radiograph quality and exposure time in turn affect the practicality of neutron radiography for specific nondestructive inspection applications. A brief discussion of fast neutron radiography using californium-252 neutron sources is also included. (U.S.)

H- radio frequency source development at the Spallation Neutron Source.

Science.gov (United States)

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

2012-02-01

The Spallation Neutron Source (SNS) now routinely operates nearly 1 MW of beam power on target with a highly persistent ∼38 mA peak current in the linac and an availability of ∼90%. H(-) beam pulses (∼1 ms, 60 Hz) are produced by a Cs-enhanced, multicusp ion source closely coupled with an electrostatic low energy beam transport (LEBT), which focuses the 65 kV beam into a radio frequency quadrupole accelerator. The source plasma is generated by RF excitation (2 MHz, ∼60 kW) of a copper antenna that has been encased with a thickness of ∼0.7 mm of porcelain enamel and immersed into the plasma chamber. The ion source and LEBT normally have a combined availability of ∼99%. Recent increases in duty-factor and RF power have made antenna failures a leading cause of downtime. This report first identifies the physical mechanism of antenna failure from a statistical inspection of ∼75 antennas which ran at the SNS, scanning electron microscopy studies of antenna surface, and cross sectional cuts and analysis of calorimetric heating measurements. Failure mitigation efforts are then described which include modifying the antenna geometry and our acceptance∕installation criteria. Progress and status of the development of the SNS external antenna source, a long-term solution to the internal antenna problem, are then discussed. Currently, this source is capable of delivering comparable beam currents to the baseline source to the SNS and, an earlier version, has briefly demonstrated unanalyzed currents up to ∼100 mA (1 ms, 60 Hz) on the test stand. In particular, this paper discusses plasma ignition (dc and RF plasma guns), antenna reliability, magnet overheating, and insufficient beam persistence.

Use of delayed gamma rays for active non-destructive assay of {sup 235}U irradiated by pulsed neutron source (plasma focus)

Energy Technology Data Exchange (ETDEWEB)

Andola, Sanjay; Niranjan, Ram [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kaushik, T.C., E-mail: tckk@barc.gov.in [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Rout, R.K. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kumar, Ashwani; Paranjape, D.B.; Kumar, Pradeep; Tomar, B.S.; Ramakumar, K.L. [Radioanalytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Gupta, S.C. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

2014-07-01

A pulsed neutron source based on plasma focus device has been used for active interrogation and assay of {sup 235}U by monitoring its delayed high energy γ-rays. The method involves irradiation of fissile material by thermal neutrons obtained after moderation of a burst of neutrons emitted upon fusion of deuterium in plasma focus (PF) device. The delayed gamma rays emitted from the fissile material as a consequence of induced fission were detected by a large volume sodium iodide (NaI(Tl)) detector. The detector is coupled to a data acquisition system of 2k input size with 2k ADC conversion gain. Counting was carried out in pulse height analysis mode for time integrated counts up to 100 s while the temporal profile of delayed gamma has been obtained by counting in multichannel scaling mode with dwell time of 50 ms. To avoid the effect of passive (natural) and active (from surrounding materials) backgrounds, counts have been acquired for gamma energy between 3 and 10 MeV. The lower limit of detection of {sup 235}U in the oxide samples with this set-up is estimated to be 14 mg.

Outline of spallation neutron source engineering

Energy Technology Data Exchange (ETDEWEB)

Watanabe, Noboru [Center for Neutron Science, Tokai Research Establishment, Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan)

2001-01-01

Slow neutrons such as cold and thermal neutrons are unique probes which can determine structures and dynamics of condensed matter in atomic scale. The neutron scattering technique is indispensable not only for basic sciences such as condensed matter research and life science, but also for basic industrial technology in 21 century. It is believed that to survive in the science-technology competition in 21 century would be almost impossible without neutron scattering. However, the intensity of neutrons presently available is much lower than synchrotron radiation sources, etc. Thus, R and D of intense neutron sources become most important. The High-Intensity Proton Accelerator Project is now being promoted jointly by Japan Atomic Energy Research Institute and High Energy Accelerator Research Organization, but there has so far been no good text which covers all the aspects of pulsed spallation neutron sources. The present review was prepare aiming at giving a better understanding on pulsed spallation neutron sources not only to neutron source researchers but also more widely to neutron scattering researchers and accelerator scientists in this field. The contents involve, starting from what is neutron scattering and what neutrons are necessary for neutron scattering, what is the spallation reaction, how to produce neutrons required for neutron scattering more efficiently, target-moderator-reflector neutronics and its engineering, shielding, target station, material issues, etc. The author have engaged in R and D of pulsed apallation neutron sources and neutron scattering research using them over 30 years. The present review is prepared based on the author's experiences with useful information obtained through ICANS collaboration and recent data from the JSNS (Japanese Spallation Neutron Source) design team. (author)

14 MeV calibration of JET neutron detectors—phase 1: calibration and characterization of the neutron source

Science.gov (United States)

Batistoni, P.; Popovichev, S.; Cufar, A.; Ghani, Z.; Giacomelli, L.; Jednorog, S.; Klix, A.; Lilley, S.; Laszynska, E.; Loreti, S.; Packer, L.; Peacock, A.; Pillon, M.; Price, R.; Rebai, M.; Rigamonti, D.; Roberts, N.; Tardocchi, M.; Thomas, D.; Contributors, JET

2018-02-01

In view of the planned DT operations at JET, a calibration of the JET neutron monitors at 14 MeV neutron energy is needed using a 14 MeV neutron generator deployed inside the vacuum vessel by the JET remote handling system. The target accuracy of this calibration is  ±10% as also required by ITER, where a precise neutron yield measurement is important, e.g. for tritium accountancy. To achieve this accuracy, the 14 MeV neutron generator selected as the calibration source has been fully characterised and calibrated prior to the in-vessel calibration of the JET monitors. This paper describes the measurements performed using different types of neutron detectors, spectrometers, calibrated long counters and activation foils which allowed us to obtain the neutron emission rate and the anisotropy of the neutron generator, i.e. the neutron flux and energy spectrum dependence on emission angle, and to derive the absolute emission rate in 4π sr. The use of high resolution diamond spectrometers made it possible to resolve the complex features of the neutron energy spectra resulting from the mixed D/T beam ions reacting with the D/T nuclei present in the neutron generator target. As the neutron generator is not a stable neutron source, several monitoring detectors were attached to it by means of an ad hoc mechanical structure to continuously monitor the neutron emission rate during the in-vessel calibration. These monitoring detectors, two diamond diodes and activation foils, have been calibrated in terms of neutrons/counts within  ±5% total uncertainty. A neutron source routine has been developed, able to produce the neutron spectra resulting from all possible reactions occurring with the D/T ions in the beam impinging on the Ti D/T target. The neutron energy spectra calculated by combining the source routine with a MCNP model of the neutron generator have been validated by the measurements. These numerical tools will be key in analysing the results from the in

Accelerator based neutron source for neutron capture therapy

International Nuclear Information System (INIS)

Salimov, R.; Bayanov, B.; Belchenko, Yu.; Belov, V.; Davydenko, V.; Donin, A.; Dranichnikov, A.; Ivanov, A.; Kandaurov, I; Kraynov, G.; Krivenko, A.; Kudryavtsev, A.; Kursanov, N.; Savkin, V.; Shirokov, V.; Sorokin, I.; Taskaev, S.; Tiunov, M.

2004-01-01

Full text: The Budker Institute of Nuclear Physics (Novosibirsk) and the Institute of Physics and Power Engineering (Obninsk) have proposed an accelerator based neutron source for neutron capture and fast neutron therapy for hospital. Innovative approach is based upon vacuum insulation tandem accelerator (VITA) and near threshold 7 Li(p,n) 7 Be neutron generation. Pilot accelerator based neutron source for neutron capture therapy is under construction now at the Budker Institute of Nuclear Physics, Novosibirsk, Russia. In the present report, the pilot facility design is presented and discussed. Design features of facility components are discussed. Results of experiments and simulations are presented. Complete experimental tests are planned by the end of the year 2005

Spectrometers for compact neutron sources

Science.gov (United States)

Voigt, J.; Böhm, S.; Dabruck, J. P.; Rücker, U.; Gutberlet, T.; Brückel, T.

2018-03-01

We discuss the potential for neutron spectrometers at novel accelerator driven compact neutron sources. Such a High Brilliance Source (HBS) relies on low energy nuclear reactions, which enable cryogenic moderators in very close proximity to the target and neutron optics at comparably short distances from the moderator compared to existing sources. While the first effect aims at increasing the phase space density of a moderator, the second allows the extraction of a large phase space volume, which is typically requested for spectrometer applications. We find that competitive spectrometers can be realized if (a) the neutron production rate can be synchronized with the experiment repetition rate and (b) the emission characteristics of the moderator can be matched to the phase space requirements of the experiment. MCNP simulations for protons or deuterons on a Beryllium target with a suitable target/moderator design yield a source brightness, from which we calculate the sample fluxes by phase space considerations for different types of spectrometers. These match closely the figures of todays spectrometers at medium flux sources. Hence we conclude that compact neutron sources might be a viable option for next generation neutron sources.

Fission-neutrons source with fast neutron-emission timing

Energy Technology Data Exchange (ETDEWEB)

Rusev, G., E-mail: rusev@lanl.gov; Baramsai, B.; Bond, E.M.; Jandel, M.

2016-05-01

A neutron source with fast timing has been built to help with detector-response measurements. The source is based on the neutron emission from the spontaneous fission of {sup 252}Cf. The time is provided by registering the fission fragments in a layer of a thin scintillation film with a signal rise time of 1 ns. The scintillation light output is measured by two silicon photomultipliers with rise time of 0.5 ns. Overall time resolution of the source is 0.3 ns. Design of the source and test measurements using it are described. An example application of the source for determining the neutron/gamma pulse-shape discrimination by a stilbene crystal is given.

Source characterization of Purnima Neutron Generator (PNG)

International Nuclear Information System (INIS)

Bishnoi, Saroj; Patel, T.; Paul, Ram K.; Sarkar, P.S.; Adhikari, P.S.; Sinha, Amar

2011-01-01

The use of 14.1 MeV neutron generators for the applications such as elemental analysis, Accelerated Driven System (ADS) study, fast neutron radiography requires the characterization of neutron source i.e neutron yield (emission rate in n/sec), neutron dose, beam spot size and energy spectrum. In this paper, a series of experiments carried out to characterize this neutron source. The neutron source has been quantified with neutron emission rate, neutron dose at various source strength and beam spot size at target position

Mean energy polarized neutron source

International Nuclear Information System (INIS)

Aleshin, V.A.; Zaika, N.I.; Kolotyj, V.V.; Prokopenko, V.S.; Semenov, V.S.

1988-01-01

Physical bases and realization scheme of a pulsed source of polarized neutrons with the energy of up to 75 MeV are described. The source comprises polarized deuteron source, transport line, low-energy ion and axial injector to the accelerator, U-240 isochronous cyclotron, targets for polarized neutron production, accelerated deuteron transport line and flight bases. The pulsed source of fast neutrons with the energy of up to 75 MeV can provide for highly polarized neutron beams with the intensity by 2-3 orders higher than in the most perfect source of this range which allows one to perform various experiments with high efficiency and energy resolution. 9 refs.; 1 fig

Neutron producing reactions in PuBe neutron sources

Energy Technology Data Exchange (ETDEWEB)

Bagi, János [European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU) (Germany); Lakosi, László; Nguyen, Cong Tam [Centre for Energy Research, Hungarian Academy of Sciences, Budapest (Hungary)

2016-01-01

There are a plenty of out-of-use plutonium–beryllium neutron sources in Eastern Europe presenting both nuclear safeguards and security issues. Typically, their actual Pu content is not known. In the last couple of years different non-destructive methods were developed for their characterization. For such methods detailed knowledge of the nuclear reactions taking place within the source is necessary. In this paper we investigate the role of the neutron producing reactions, their contribution to the neutron yield and their dependence on the properties of the source.

Instrumentation at pulsed neutron sources

International Nuclear Information System (INIS)

Carpenter, J.M.; Lander, G.H.; Windsor, C.G.

1984-01-01

Scientific investigations involving the use of neutron beams have been centered at reactor sources for the last 35 years. Recently, there has been considerable interest in using the neutrons produced by accelerator driven (pulsed) sources. Such installations are in operation in England, Japan, and the United States. In this article a brief survey is given of how the neutron beams are produced and how they can be optimized for neutron scattering experiments. A detailed description is then given of the various types of instruments that have been, or are planned, at pulsed sources. Numerous examples of the scientific results that are emerging are given. An attempt is made throughout the article to compare the scientific opportunities at pulsed sources with the proven performance of reactor installations, and some familiarity with the latter and the general field of neutron scattering is assumed. New areas are being opened up by pulsed sources, particularly with the intense epithermal neutron beams, which promise to be several orders of magnitude more intense than can be obtained from a thermal reactor

Neutron cooling and cold-neutron sources (1962)

International Nuclear Information System (INIS)

Jacrot, B.

1962-01-01

Intense cold-neutron sources are useful in studying solids by the inelastic scattering of neutrons. The paper presents a general survey covering the following aspects: a) theoretical considerations put forward by various authors regarding thermalization processes at very low temperatures; b) the experiments that have been carried out in numerous laboratories with a view to comparing the different moderators that can be used; c) the cold neutron sources that have actually been produced in reactors up to the present time, and the results obtained with them. (author) [fr

Pulsed neutron sources at Dubna

International Nuclear Information System (INIS)

Shabalin, E.P.

1991-01-01

In 1960 the first world repetitively pulsed reactor IBR was put into operation. It was the beginning of the story how fission based pulsed neutron sources at Dubna have survived. The engineers involved have experienced many successes and failures in the course of new sources upgrading to finally come to possess the world's brightest neutron source - IBR-2. The details are being reviewed through the paper. The fission based pulsed neutron sources did not reach their final state as yet- the conceptual views of IBR prospects are being discussed with the goal to double the thermal neutron peak flux (up to 2x10 16 ) and to enhance the cold neutron flux by 10 times (with the present one being as high that of the ISIS cold moderator). (author)

H{sup -} radio frequency source development at the Spallation Neutron Source

Energy Technology Data Exchange (ETDEWEB)

Welton, R. F.; Gawne, K. R.; Han, B. X.; Murray, S. N.; Pennisi, T. R.; Roseberry, R. T.; Santana, M.; Stockli, M. P. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37830-6471 (United States); Dudnikov, V. G. [Muons, Inc., 552 N. Batavia Avenue, Batavia, Illinois 60510 (United States); Turvey, M. W. [Villanova University, 800E. Lancaster Ave, Villanova, Pennsylvania 19085 (United States)

2012-02-15

The Spallation Neutron Source (SNS) now routinely operates nearly 1 MW of beam power on target with a highly persistent {approx}38 mA peak current in the linac and an availability of {approx}90%. H{sup -} beam pulses ({approx}1 ms, 60 Hz) are produced by a Cs-enhanced, multicusp ion source closely coupled with an electrostatic low energy beam transport (LEBT), which focuses the 65 kV beam into a radio frequency quadrupole accelerator. The source plasma is generated by RF excitation (2 MHz, {approx}60 kW) of a copper antenna that has been encased with a thickness of {approx}0.7 mm of porcelain enamel and immersed into the plasma chamber. The ion source and LEBT normally have a combined availability of {approx}99%. Recent increases in duty-factor and RF power have made antenna failures a leading cause of downtime. This report first identifies the physical mechanism of antenna failure from a statistical inspection of {approx}75 antennas which ran at the SNS, scanning electron microscopy studies of antenna surface, and cross sectional cuts and analysis of calorimetric heating measurements. Failure mitigation efforts are then described which include modifying the antenna geometry and our acceptance/installation criteria. Progress and status of the development of the SNS external antenna source, a long-term solution to the internal antenna problem, are then discussed. Currently, this source is capable of delivering comparable beam currents to the baseline source to the SNS and, an earlier version, has briefly demonstrated unanalyzed currents up to {approx}100 mA (1 ms, 60 Hz) on the test stand. In particular, this paper discusses plasma ignition (dc and RF plasma guns), antenna reliability, magnet overheating, and insufficient beam persistence.

Neutron scattering instrumentation for biology at spallation neutron sources

Energy Technology Data Exchange (ETDEWEB)

Pynn, R. [Los Alamos National Laboratory, NM (United States)

1994-12-31

Conventional wisdom holds that since biological entities are large, they must be studied with cold neutrons, a domain in which reactor sources of neutrons are often supposed to be pre-eminent. In fact, the current generation of pulsed spallation neutron sources, such as LANSCE at Los Alamos and ISIS in the United Kingdom, has demonstrated a capability for small angle scattering (SANS) - a typical cold- neutron application - that was not anticipated five years ago. Although no one has yet built a Laue diffractometer at a pulsed spallation source, calculations show that such an instrument would provide an exceptional capability for protein crystallography at one of the existing high-power spoliation sources. Even more exciting is the prospect of installing such spectrometers either at a next-generation, short-pulse spallation source or at a long-pulse spallation source. A recent Los Alamos study has shown that a one-megawatt, short-pulse source, which is an order of magnitude more powerful than LANSCE, could be built with today`s technology. In Europe, a preconceptual design study for a five-megawatt source is under way. Although such short-pulse sources are likely to be the wave of the future, they may not be necessary for some applications - such as Laue diffraction - which can be performed very well at a long-pulse spoliation source. Recently, it has been argued by Mezei that a facility that combines a short-pulse spallation source similar to LANSCE, with a one-megawatt, long-pulse spallation source would provide a cost-effective solution to the global shortage of neutrons for research. The basis for this assertion as well as the performance of some existing neutron spectrometers at short-pulse sources will be examined in this presentation.

Measurements of the neutron yield from a coaxial gun plasma

International Nuclear Information System (INIS)

Zolototrubov, I.M.; Krasnikov, A.A.; Kurishchenko, A.M.; Novikov, Yu.M.; Poryatuj, V.S.; Tolstolutskij, A.G.

1977-01-01

Neutron yield from deuterium plasma produced by a pulse coaxial accelerator was measured. The maximum neutron yield with 5 kj stored in a condenser battery is 3x10 6 neutron/pulse. The basis of the method of measuring neutron yield from the plasma was through the induced activity. It was shown that application of even a small uniform longitudinal magnetic field (up to 1 kOe) on the accelerator decreases several times the neutron yield. It is also shown that a small amount of stored discharge energy can produce high-temperature plasma at the output of pulse coaxial accelerator in the absense of the direct magnetic field. It is supposed that the reason for the reduction of neutron yield level in the case of applying the magnetic field is decreasing plasma density because of increasing the bunch cross-section

Development of compact size penning ion source for compact neutron generator.

Science.gov (United States)

Das, Basanta Kumar; Shyam, Anurag

2008-12-01

For long-life operation, easy to mount and compact in size penning type ion sources are widely used in different fields of research such as neutron generators, material research, and surface etching. One penning type ion source has been developed in our laboratory. Applying high voltage of 2 kV between two oppositely biased electrodes and using permanent magnet of 500 gauss magnetic field along the axis, we had produced the glow discharge in the plasma region. The performance of this source was investigated using nitrogen gas. Deuterium ions were produced and extracted on the basis of chosen electrodes and the angle of extraction. Using a single aperture plasma electrode, the beam was extracted along the axial direction. The geometry of plasma electrode is an important factor for the efficient extraction of the ions from the plasma ion source. The extracted ion current depends upon the shape of the plasma meniscus. A concave shaped plasma meniscus produces converged ion beam. The convergence of extracted ions is related to the extraction electrode angle. The greater the angle, the more the beam converges. We had studied experimentally this effect with a compact size penning ion source. The detailed comparison among the different extraction geometry and different electrode angle are discussed in this paper.

Neutron spectra and dosimetric features of isotopic neutron sources: a review

International Nuclear Information System (INIS)

Vega C, H. R.; Martinez O, S. A.

2015-10-01

A convenient way to produce neutrons is the isotopic neutron source, where the production is through (α, n), (γ, n), and spontaneous fission reactions. Isotopic neutron sources are small, easy to handle, and have a relative low cost. On the other hand the neutron yield is small and mostly of them produces neutrons with a wide energy distribution. In this work, a review is carried out about the the main features of 24 NaBe, 24 NaD 2 O, 116 InBe, 140 LaBe, 238 PuLi, 239 PuBe, 241 AmB, 241 AmBe, 241 AmF, 241 AmLi, 242 CmBe, 210 PoBe, 226 RaBe, 252 Cf and 252 Cf/D 2 O isotopic neutron source. Also, using Monte Carlo methods, the neutron spectra in 31 energy groups, the neutron mean energy; the Ambient dose equivalent, the Personal dose equivalent and the Effective dose were calculated for these isotopic neutron sources. (Author)

Advanced neutron source project

International Nuclear Information System (INIS)

Gorynina, L.V.; Proskuryakov, S.F.; Tishchenko, V.A.; Uzhanova, V.V.

1991-01-01

The project of the ANS improved neutron source intended for fundamental researches in nuclear physics and materials testing is considered. New superhigh-flux heavy-water 350 MW reactor is used for the source creation. The standard fuel is uranium silicide (U 3 Si 2 ). Reactor core volume equals 67.4 l and average power density is 4.9 MW/l. Neutron flux density is 10 16 neutron/(cm 2 xs). The facility construction begin is planned for 1996. The first experiments should be accomplished in 2000

Fission and activation of uranium by fashion-plasma neutrons

International Nuclear Information System (INIS)

Lee, J.H.; Hochl, F.; McFarland, D.R.

1978-01-01

Disks of enriched and depleted uranium were irradiated by neutrons from the D-D fusions in a dense plasma-focus. A fission yield of 10 6 fissions-cm -3 in U 235 per pulse was determined with Ge(Li) gamme-ray spectrometry. Activation of U 238 caused increased beta activity after the plasma-neutron irradiation but alpha-particle spectrometry showed Pu 239 production was negligible. In addition, with a disk of lithium in the apparatus, 13.3 MeV neutrons from 7 Li(d,n) 8 Be was observed with a 80-m time-of-flight neutron detector. Dense plasma focuses are now operated not only in a single coaxial gun, but also in improved geometries, such as the hypocycloidal pinch and the staged plasma focus, from which a multiple plasma-focus array suitable for experimental verification of, and eventuel development into a fusion-fission hybrid reactor could be produced. (orig.) [de

A GDT-based fusion neutron source for academic and industrial applications

Science.gov (United States)

Anderson, J. K.; Forest, C. B.; Mirnov, V. V.; Peterson, E. E.; Waleffe, R.; Wallace, J.; Harvey, R. W.

2017-10-01

The design of a fusion neutron source based on the gas dynamic trap (GDT) configuration is underway. The motivation is both the ends and the means. There are immediate applications for neutrons including medical isotope production and actinide burners. Taking the next step in the magnetic mirror path will leverage advances in high-temperature superconducting magnets and additive manufacturing in confining a fusion plasma, and both the technological and physics bases exist. Recent breakthrough results at the GDT facility in Russia demonstrate stable confinement of a beta 60% mirror plasma at high Te ( 1 keV). These scale readily to a fusion neutron source with an increase in magnetic field, mirror ratio, and ion energy. Studies of a next-step compact device focus on calculations of MHD equilibrium and stability, and Fokker-Planck modeling to optimize the heating scenario. The conceptualized device uses off-the-shelf MRI magnets for a 1 T central field, REBCO superconducting mirror coils (which can currently produce fields in excess of 30T), and existing 75 keV NBI and 140 GHz ECRH. High harmonic fast wave injection is damped on beam ions, dramatically increasing the fusion reactivity for an incremental bump in input power. MHD stability is achieved with the vortex confinement scheme, where a biasing profile imposes optimal ExB rotation of the plasma. Liquid metal divertors are being considered in the end cells. Work supported by the Wisconsin Alumni Research Foundation.

Cyclotron-based neutron source for BNCT

Energy Technology Data Exchange (ETDEWEB)

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

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.

Pulsed spallation Neutron Sources

International Nuclear Information System (INIS)

Carpenter, J.M.

1994-01-01

This paper reviews the early history of pulsed spallation neutron source development at 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 provides a few examples of applications in fundamental condensed matter physics, materials science and technology

Pulsed spallation neutron sources

International Nuclear Information System (INIS)

Carpenter, J.M.

1996-01-01

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

Spallation source neutron target systems

International Nuclear Information System (INIS)

Russell, G.; Brown, R.; Collier, M.; Donahue, J.

1996-01-01

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

A Wide Spectrum Neutron Polarizer for a Pulsed Neutron Source

International Nuclear Information System (INIS)

Nikitenko, Yu.V.

1994-01-01

A wide spectrum neutron polarizer for a pulsed neutron source is considered. The polarizer is made in a form of a set of magnetized mirrors placed on a drum. Homogeneous rotation of the polarizer is synchronized with the power pulses of the neutron source. The polarizer may be utilized in a collimated neutron beam with cross section of the order of magnitude of 100 cm 2 within a wavelength from 2 up to 20 A on sources with a pulse repetition frequency up to 50 Hz. (author). 5 refs.; 3 figs

The advanced neutron source

International Nuclear Information System (INIS)

Hayter, J.B.

1994-01-01

The Advanced Neutron Source (ANS), slated for construction start in 1994, will be a multipurpose neutron research laboratory serving academic and industrial users in chemistry, biology, condensed matter physics, nuclear and fundamental physics, materials science and engineering, and many other fields. It will be centered on the world's highest flux neutron beam reactor, operating at 330 MW, with careful design integration between the neutron source and the experiment systems. Many instruments will be situated in low backgrounds at distances up to 80 m from the reactor, using neutron guides with tailored neutron optical coatings for beam transport. Apart from the many stations for neutron scattering research, specialized stations will also be provided for isotope separation on-line, experiments with liquid hydrogen targets, neutron optical techniques such as interferometry, activation analysis, depth profiling, and positron production. Careful consideration has been given to providing a good research environment for visiting scientists, including easy access to the experimental areas, while maintaining a highly secure nuclear facility. This paper will describe the reactor and experimental facilities and give some examples of the types of research for which ANS has been designed

Fundamental neutron physics at a 1 MW long pulse spallation neutron source

International Nuclear Information System (INIS)

Greene, G.L.

1995-01-01

Modern neutron sources and modern neutron science share a common origin in mid twentieth century scientific investigations concerned with the study of the fundamental interactions between elementary particles. Since the time of that common origin, neutron science and the study of elementary particles have evolved into quite disparate disciplines. The neutron became recognized as a powerful tool for the study of condensed matter with modern neutron sources being primarily used (and primarily justified) as tools for condensed matter research. The study of elementary particles has, of course, led to the development of rather different tools and is now dominated by activities carried out at extremely high energies. Notwithstanding this trend, the study of fundamental interactions using neutrons has continued and remains a vigorous activity at many contemporary neutron sources. This research, like neutron scattering research, has benefited enormously by the development of modern high flux neutron facilities. Future sources, particularly high power spallation sources, offer exciting possibilities for the continuation of this program of research

New neutron physics using spallation sources

International Nuclear Information System (INIS)

Bowman, C.D.

1988-01-01

The extraordinary neutron intensities available from the new spallation pulsed neutron sources open up exciting opportunities for basic and applied research in neutron nuclear physics. The energy range of neutron research which is being explored with these sources extends from thermal energies to almost 800 MeV. The emphasis here is on prospective experiments below 100 keV neutron energy using the intense neutron bursts produced by the Proton Storage Ring (PSR) at Los Alamos. 30 refs., 10 figs

Spherical neutron generator

Science.gov (United States)

Leung, Ka-Ngo

2006-11-21

A spherical neutron generator is formed with a small spherical target and a spherical shell RF-driven plasma ion source surrounding the target. A deuterium (or deuterium and tritium) ion plasma is produced by RF excitation in the plasma ion source using an RF antenna. The plasma generation region is a spherical shell between an outer chamber and an inner extraction electrode. A spherical neutron generating target is at the center of the chamber and is biased negatively with respect to the extraction electrode which contains many holes. Ions passing through the holes in the extraction electrode are focused onto the target which produces neutrons by D-D or D-T reactions.

Neutron spectra and dosimetric features of isotopic neutron sources: a review

Energy Technology Data Exchange (ETDEWEB)

Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas, Zac. (Mexico); Martinez O, S. A., E-mail: fermineutron@yahoo.com [Universidad Pedagogica y Tecnologica de Colombia, Grupo de Fisica Nuclear Aplicada y Simulacion, Av. Central del Norte 39-115, 150003 Tunja, Boyaca (Colombia)

2015-10-15

A convenient way to produce neutrons is the isotopic neutron source, where the production is through (α, n), (γ, n), and spontaneous fission reactions. Isotopic neutron sources are small, easy to handle, and have a relative low cost. On the other hand the neutron yield is small and mostly of them produces neutrons with a wide energy distribution. In this work, a review is carried out about the the main features of {sup 24}NaBe, {sup 24}NaD{sub 2}O, {sup 116}InBe, {sup 140}LaBe, {sup 238}PuLi, {sup 239}PuBe, {sup 241}AmB, {sup 241}AmBe, {sup 241}AmF, {sup 241}AmLi, {sup 242}CmBe, {sup 210}PoBe, {sup 226}RaBe, {sup 252}Cf and {sup 252}Cf/D{sub 2}O isotopic neutron source. Also, using Monte Carlo methods, the neutron spectra in 31 energy groups, the neutron mean energy; the Ambient dose equivalent, the Personal dose equivalent and the Effective dose were calculated for these isotopic neutron sources. (Author)

Calculations to support JET neutron yield calibration: Modelling of neutron emission from a compact DT neutron generator

Science.gov (United States)

Čufar, Aljaž; Batistoni, Paola; Conroy, Sean; Ghani, Zamir; Lengar, Igor; Milocco, Alberto; Packer, Lee; Pillon, Mario; Popovichev, Sergey; Snoj, Luka; JET Contributors

2017-03-01

At the Joint European Torus (JET) the ex-vessel fission chambers and in-vessel activation detectors are used as the neutron production rate and neutron yield monitors respectively. In order to ensure that these detectors produce accurate measurements they need to be experimentally calibrated. A new calibration of neutron detectors to 14 MeV neutrons, resulting from deuterium-tritium (DT) plasmas, is planned at JET using a compact accelerator based neutron generator (NG) in which a D/T beam impinges on a solid target containing T/D, producing neutrons by DT fusion reactions. This paper presents the analysis that was performed to model the neutron source characteristics in terms of energy spectrum, angle-energy distribution and the effect of the neutron generator geometry. Different codes capable of simulating the accelerator based DT neutron sources are compared and sensitivities to uncertainties in the generator's internal structure analysed. The analysis was performed to support preparation to the experimental measurements performed to characterize the NG as a calibration source. Further extensive neutronics analyses, performed with this model of the NG, will be needed to support the neutron calibration experiments and take into account various differences between the calibration experiment and experiments using the plasma as a source of neutrons.

Calculations to support JET neutron yield calibration: Modelling of neutron emission from a compact DT neutron generator

Energy Technology Data Exchange (ETDEWEB)

Čufar, Aljaž, E-mail: aljaz.cufar@ijs.si [Reactor Physics Department, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Batistoni, Paola [ENEA, Department of Fusion and Nuclear Safety Technology, I-00044 Frascati, Rome (Italy); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Conroy, Sean [Uppsala University, Department of Physics and Astronomy, PO Box 516, SE-75120 Uppsala (Sweden); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Ghani, Zamir [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Lengar, Igor [Reactor Physics Department, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Milocco, Alberto; Packer, Lee [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Pillon, Mario [ENEA, Department of Fusion and Nuclear Safety Technology, I-00044 Frascati, Rome (Italy); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Popovichev, Sergey [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Snoj, Luka [Reactor Physics Department, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); EUROfusion Consortium, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)

2017-03-01

At the Joint European Torus (JET) the ex-vessel fission chambers and in-vessel activation detectors are used as the neutron production rate and neutron yield monitors respectively. In order to ensure that these detectors produce accurate measurements they need to be experimentally calibrated. A new calibration of neutron detectors to 14 MeV neutrons, resulting from deuterium–tritium (DT) plasmas, is planned at JET using a compact accelerator based neutron generator (NG) in which a D/T beam impinges on a solid target containing T/D, producing neutrons by DT fusion reactions. This paper presents the analysis that was performed to model the neutron source characteristics in terms of energy spectrum, angle–energy distribution and the effect of the neutron generator geometry. Different codes capable of simulating the accelerator based DT neutron sources are compared and sensitivities to uncertainties in the generator's internal structure analysed. The analysis was performed to support preparation to the experimental measurements performed to characterize the NG as a calibration source. Further extensive neutronics analyses, performed with this model of the NG, will be needed to support the neutron calibration experiments and take into account various differences between the calibration experiment and experiments using the plasma as a source of neutrons.

Cold source vessel development for the advanced neutron source

Energy Technology Data Exchange (ETDEWEB)

Williams, P.T.; Lucas, A.T. [Oak Ridge National Lab., TN (United States)

1995-09-01

The Advanced Neutron Source (ANS), in its conceptual design phase at Oak Ridge National Laboratory (ORNL), will be a user-oriented neutron research facility that will produce the most intense flux of neutrons in the world. Among its many scientific applications, the productions of cold neutrons is a significant research mission for the ANS. The cold neutrons come from two independent cold sources positioned near the reactor core. Contained by an aluminum alloy vessel, each cold source is a 410 mm diameter sphere of liquid deuterium that functions both as a neutron moderator and a cryogenic coolant. With nuclear heating of the containment vessel and internal baffling, steady-state operation requires close control of the liquid deuterium flow near the vessel`s inner surface. Preliminary thermal-hydraulic analyses supporting the cold source design are being performed with multi-dimensional computational fluid dynamics simulations of the liquid deuterium flow and heat transfer. This paper presents the starting phase of a challenging program and describes the cold source conceptual design, the thermal-hydraulic feasibility studies of the containment vessel, and the future computational and experimental studies that will be used to verify the final design.

Application of the guiding centre approximation to the transport of injected fast ions in a mirror based plasma neutron source

International Nuclear Information System (INIS)

Kumpf, H.; Noack, K.

1996-01-01

The guiding centre approximation for the motion of charged particles in axially symmetric magnetic and electric fields is formulated and stopping as well as small angle scattering on a multicomponent plasma are included. The developed code has been applied to the design of a 14-MeV neutron source according to the concept of the Budker Institute Novosibirsk. It is demonstrated that the self-interaction of injected D and T ions by stopping, scattering and induced internal fields has to be taken into account, if the injected power exceeds a few megawatt. (orig.)

Neutronics of the IFMIF neutron source: development and analysis

International Nuclear Information System (INIS)

Wilson, P.P.H.

1999-01-01

The accurate analysis of this system required the development of a code system and methodology capable of modelling the various physical processes. A generic code system for the neutronics analysis of neutron sources has been created by loosely integrating existing components with new developments: the data processing code NJOY, the Monte Carlo neutron transport code MCNP, and the activation code ALARA were supplemented by a damage data processing program, damChar, and integrated with a number of flexible and extensible modules for the Perl scripting language. Specific advances were required to apply this code system to IFMIF. Based on the ENDF-6 data format requirements of this system, new data evaluations have been implemented for neutron transport and activation. Extensive analysis of the Li(d, xn) reaction has led to a new MCNP source function module, M c DeLi, based on physical reaction models and capable of accurate and flexible modelling of the IFMIF neutron source term. In depth analyses of the neutron flux spectra and spatial distribution throughout the high flux test region permitted a basic validation of the tools and data. The understanding of the features of the neutron flux provided a foundation for the analyses of the other neutron responses. (orig./DGE) [de

New sources and instrumentation for neutron science

International Nuclear Information System (INIS)

Gil, Alina

2011-01-01

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.

New sources and instrumentation for neutron science

Energy Technology Data Exchange (ETDEWEB)

Gil, Alina, E-mail: a.gil@ajd.czest.pl [Faculty of Mathematical and Natural Sciences, JD University, Al. Armii Krajowej 13/15, 42-200 Czestochowa (Poland)

2011-04-01

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.

(International Collaboration on Advanced Neutron Sources)

Energy Technology Data Exchange (ETDEWEB)

Hayter, J.B.

1990-11-08

The International Collaboration on Advanced Neutron Sources was started about a decade ago with the purpose of sharing information throughout the global neutron community. The collaboration has been extremely successful in optimizing the use of resources, and the discussions are open and detailed, with reasons for failure shared as well as reasons for success. Although the meetings have become increasingly oriented toward pulsed neutron sources, many of the neutron instrumentation techniques, such as the development of better monochromators, fast response detectors and various data analysis methods, are highly relevant to the Advanced Neutron Source (ANS). I presented one paper on the ANS, and another on the neutron optical polarizer design work which won a 1989 R D-100 Award. I also gained some valuable design ideas, in particular for the ANS hot source, in discussions with individual researchers from Canada, Western Europe, and Japan.

Accelerator-based pulsed cold neutron source

International Nuclear Information System (INIS)

Inoue, Kazuhiko; Iwasa, Hirokatsu; Kiyanagi, Yoshiaki

1979-01-01

An accelerator-based pulsed cold neutron source was constructed. The accelerator is a 35 MeV electron linear accelerator with 1 kW average beam power. The cold neutron beam intensity at a specimen is equivalent to that of a research reactor of 10 14 n/cm 2 .s thermal flux in the case of the quasi-elastic neutron scattering measurements. In spite of some limitations to the universal uses, it has been demonstrated by this facility that the modest capacity accelerator-based pulsed cold neutron source is a highly efficient cold neutron source with low capital investment. Design philosophy, construction details, performance and some operational experiences are described. (author)

Radioactive source recovery program responses to neutron source emergencies

International Nuclear Information System (INIS)

Dinehart, S.M.; Hatler, V.A.; Gray, D.W.; Guillen, A.D.

1997-01-01

Recovery of neutron sources containing Pu 239 and Be is currently taking place at Los Alamos National Laboratory. The program was initiated in 1979 by the Department of Energy (DOE) to dismantle and recover sources owned primarily by universities and the Department of Defense. Since the inception of this program, Los Alamos has dismantled and recovered more than 1000 sources. The dismantlement and recovery process involves the removal of source cladding and the chemical separation of the source materials to eliminate neutron emissions. While this program continues for the disposal of 239 Pu/Be sources, there is currently no avenue for the disposition of any sources other than those containing Pu 239 . Increasingly, there have been demands from agencies both inside and outside the Federal Government and from the public to dispose of unwanted sources containing 238 Pu/Be and 241 Am/Be. DOE is attempting to establish a formal program to recover these sources and is working closely with the Nuclear Regulatory Commission (NRC) on a proposed Memorandum of Understanding to formalize an Acceptance Program. In the absence of a formal program to handle 238 Pu/Be and 241 Am/Be neutron sources, Los Alamos has responded to several emergency requests to receive and recover sources that have been determined to be a threat to public health and safety. This presentation will: (1) review the established 239 Pu neutron source recovery program at Los Alamos, (2) detail plans for a more extensive neutron source disposal program, and (3) focus on recent emergency responses

Different spectra with the same neutron source

International Nuclear Information System (INIS)

Vega C, H. R.; Ortiz R, J. M.; Hernandez D, V. M.; Martinez B, M. R.; Hernandez A, B.; Ortiz H, A. A.; Mercado, G. A.

2010-01-01

Using as source term the spectrum of a 239 Pu-Be source several neutron spectra have been calculated using Monte Carlo methods. The source term was located in the centre of spherical moderators made of light water, heavy water and polyethylene of different diameters. Also a 239 Pu-Be source was used to measure its neutron spectrum, bare and moderated by water. The neutron spectra were measured at 100 cm with a Bonner spheres spectrometer. Monte Carlo calculations were used to calculate the neutron spectra of bare and water-moderated spectra that were compared with those measured with the spectrometer. Resulting spectra are similar to those found in power plants with PWR, BWR and Candu nuclear reactors. Beside the spectra the dosimetric features were determined. Using moderators and a single neutron source can be produced neutron spectra alike those found in workplaces, this neutron fields can be utilized to calibrate neutron dosimeters and area monitors. (Author)

Large area solid target neutron source

International Nuclear Information System (INIS)

Crawford, J.C.; Bauer, W.

1974-01-01

A potentially useful neutron source may result from the combination of a solid deuterium-tritium loaded target with the large area, high energy ion beams from ion sources being developed for neutral beam injection. The resulting neutron source would have a large radiating area and thus produce the sizable experimental volume necessary for future studies of bulk and synergistic surface radiation effects as well as experiments on engineering samples and small components. With a 200 keV D + T + beam and 40 kW/cm 2 power dissipation on a 200 cm 2 target spot, a total neutron yield of about 4 x 10 15 n/sec may be achieved. Although the useable neutron flux from this source is limited to 1 to 2 x 10 13 n/cm 2 /sec, this flux can be produced 3 cm in front of the target and over about 300 cm 3 of experimental volume. Problems of total power dissipation, sputtering, isotopic flushing and thermal dissociation are reviewed. Neutron flux profiles and potential experimental configurations are presented and compared to other neutron source concepts. (U.S.)

Compact activation detectors for measuring of neutron emission on plasma focus installations

International Nuclear Information System (INIS)

Krokhin, O.N.; Nikulin, V.Ya.; Peregudova, E.V.; Volobuev, I.V.

2005-01-01

The paper presents the two compact simple systems for the measurement of the absolute neutron yield in the range 10 6 - 10 12 neutrons/pulse and higher and spatial anisotropy of neutron radiation. The systems are destined for the registration of the short duration neutron radiation of the pulsed plasma installations, such as Plasma Focus (PF), z-pinches and others plasma installations. This paper also includes the results of the neutron emission measurements on different PF installations: 'Tulip' (P.N. Lebedev Physical Institute, Moscow Russia), the PF-1000 and PF-150 installations (Institute of Plasma Physics and Laser Microfusion, Warsaw, Poland)

Neutron Sources for Standard-Based Testing

Energy Technology Data Exchange (ETDEWEB)

Radev, Radoslav [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McLean, Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2014-11-10

The DHS TC Standards and the consensus ANSI Standards use ²⁵²Cf as the neutron source for performance testing because its energy spectrum is similar to the ²³⁵U and ²³⁹Pu fission sources used in nuclear weapons. An emission rate of 20,000 ± 20% neutrons per second is used for testing of the radiological requirements both in the ANSI standards and the TCS. Determination of the accurate neutron emission rate of the test source is important for maintaining consistency and agreement between testing results obtained at different testing facilities. Several characteristics in the manufacture and the decay of the source need to be understood and accounted for in order to make an accurate measurement of the performance of the neutron detection instrument. Additionally, neutron response characteristics of the particular instrument need to be known and taken into account as well as neutron scattering in the testing environment.

Neutron irradiation effects on plasma facing materials

Science.gov (United States)

Barabash, V.; Federici, G.; Rödig, M.; Snead, L. L.; Wu, C. H.

2000-12-01

This paper reviews the effects of neutron irradiation on thermal and mechanical properties and bulk tritium retention of armour materials (beryllium, tungsten and carbon). For each material, the main properties affected by neutron irradiation are described and the specific tests of neutron irradiated armour materials under thermal shock and disruption conditions are summarized. Based on current knowledge, the expected thermal and structural performance of neutron irradiated armour materials in the ITER plasma facing components are analysed.

Neutron irradiation effects on plasma facing materials

International Nuclear Information System (INIS)

Barabash, V.; Federici, G.; Roedig, M.; Snead, L.L.; Wu, C.H.

2000-01-01

This paper reviews the effects of neutron irradiation on thermal and mechanical properties and bulk tritium retention of armour materials (beryllium, tungsten and carbon). For each material, the main properties affected by neutron irradiation are described and the specific tests of neutron irradiated armour materials under thermal shock and disruption conditions are summarized. Based on current knowledge, the expected thermal and structural performance of neutron irradiated armour materials in the ITER plasma facing components are analysed

Cylindrical neutron generator

Science.gov (United States)

Leung, Ka-Ngo [Hercules, CA

2008-04-22

A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.

International workshop on cold neutron sources

Energy Technology Data Exchange (ETDEWEB)

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

1991-08-01

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.

International workshop on cold neutron sources

International Nuclear Information System (INIS)

Russell, G.J.; West, C.D.

1991-08-01

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

Materials for spallation neutron sources

International Nuclear Information System (INIS)

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

1996-03-01

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

Accelerator-based neutron source and its future

International Nuclear Information System (INIS)

Kiyanagi, Yoshiaki

2008-01-01

Neutrons are useful tool for the material science and also for the industrial applications. Now, high intensity neutron sources based on MW class big accelerators are under commissioning in Japan, Japan Spallation Neutron Source (JSNS) at J-PARC and in the US, SNS. Such high power neutron sources required the moderators that can be used under high radiation field and also give high neutronic performance. We have been performing experimental and Monte Carlo simulation studies to develop the cold neutron moderator systems for the high power sources since it is becoming important for materials and life science. Hydrogen is the unique candidate at the present stage due to its high resistibility to the radiation. It was indicated the para hydrogen moderator gave a good neutronic performance by experimental results. On the other hand, in the future, low power neutron sources are recognized to be useful to perform sprouting experiments and to promote the neutron science. The moderator systems need a concept different from the high power source. Therefore, we studied neutronic performances of the mesitylene and the methane moderators to get high intensity in a definite area on the moderator surface. Single groove moderators were studied and optimal geometry and the intensity gain were obtained. The mesitylene moderator gave a rather good performance compared to the methane moderator. (author)

Comparisons of calculated and measured spectral distributions of neutrons from a 14-MeV neutron source inside the Tokamak Fusion Test Reactor

International Nuclear Information System (INIS)

Santoro, R.T.; Barnes, J.M.; Alsmiller, R.G. Jr.; Emmett, M.B.; Drischler, J.D.

1985-12-01

A recent paper presented neutron spectral distributions (energy greater than or equal to0.91 MeV) measured at various locations around the Tokamak Fusion Test Reactor (TFTR) at the Princeton Plasma Physics Laboratory. The neutron source for the series of measurements was a small D-T generator placed at various positions in the TFTR vacuum chamber. In the present paper the results of neutron transport calculations are presented and compared with these experimental data. The calculations were carried out using Monte Carlo methods and a very detailed model of the TFTR and the TFTR test cell. The calculated and experimental fluences per unit energy are compared in absolute units and are found to be in substantial agreement for five different combinations of source and detector positions

Neutron source for a reactor

International Nuclear Information System (INIS)

Kobayashi, Hiromasa.

1975-01-01

Object: To easily increase a start-up power of a reactor without irradiation in other reactors. Structure: A neutron source comprises Cf 252 , a natural antimony rod, a layer of beryllium, and a vessel of neutron source. On upper and lower portion of Cf 252 are arranged natural antimony rods, which are surrounded by the Be layer, the entirety being charged into the vessel. The Cf 252 may emit neutron, has a half life more than a period of operating cycle of the reactor and is less deteriorated even irradiated by radioactive rays while being left within the reactor. The natural antimony rod is radioactivated by neutron from Cf 252 and neutron as reactor power increases to emit γ rays. The Be absorbs γ rays to emit the neutron. The antimony rod is irradiated within the reactor. Further, since the Cf 252 is small in neutron absorption cross section, it is hard to be deteriorated even while being inserted within the reactor. (Kamimura, M.)

In situ calibration of TFTR neutron detectors

International Nuclear Information System (INIS)

Hendel, H.W.; Palladino, R.W.; Barnes, C.W.; Diesso, M.; Felt, J.S.; Jassby, D.L.; Johnson, L.C.; Ku, L.; Liu, Q.P.; Motley, R.W.; Murphy, H.B.; Murphy, J.; Nieschmidt, E.B.; Roberts, J.A.; Saito, T.; Strachan, J.D.; Waszazak, R.J.; Young, K.M.

1990-01-01

We report results of the TFTR fission detector calibration performed in December 1988. A NBS-traceable, remotely controlled 252 Cf neutron source was moved toroidally through the TFTR vacuum vessel. Detection efficiencies for two 235 U detectors were measured for 930 locations of the neutron point source in toroidal scans at 16 different major radii and vertical heights. These scans effectively simulated the volume-distributed plasma neutron source and the volume-integrated detection efficiency was found to be insensitive to plasma position. The Campbell mode is useful due to its large overlap with the count rate mode and large dynamic range. The resulting absolute plasma neutron source calibration has an uncertainty of ±13%

Pulsed neutron source and instruments at neutron facility

Energy Technology Data Exchange (ETDEWEB)

Teshigawara, Makoto; Aizawa, Kazuya; Suzuki, Jun-ichi; Morii, Yukio; Watanabe, Noboru [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1997-11-01

We report the results of design studies on the optimal target shape, target - moderator coupling, optimal layout of moderators, and neutron instruments for a next generation pulsed spallation source in JAERI. The source utilizes a projected high-intensity proton accelerator (linac: 1.5 GeV, {approx}8 MW in total beam power, compressor ring: {approx}5 MW). We discuss the target neutronics, moderators and their layout. The sources is designed to have at least 30 beam lines equipped with more than 40 instruments, which are selected tentatively to the present knowledge. (author)

The advanced neutron source

International Nuclear Information System (INIS)

Raman, S.; Hayter, J.B.

1990-01-01

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 (φ th ∼ 8 x 10 19 m -2 ·s -1 ) accompanied by extensive and comprehensive equipment and facilities for neutron-based research

Three-dimensional reconstruction of neutron, gamma-ray, and x-ray sources using spherical harmonic decomposition

Science.gov (United States)

Volegov, P. L.; Danly, C. R.; Fittinghoff, D.; Geppert-Kleinrath, V.; Grim, G.; Merrill, F. E.; Wilde, C. H.

2017-11-01

Neutron, gamma-ray, and x-ray imaging are important diagnostic tools at the National Ignition Facility (NIF) for measuring the two-dimensional (2D) size and shape of the neutron producing region, for probing the remaining ablator and measuring the extent of the DT plasmas during the stagnation phase of Inertial Confinement Fusion implosions. Due to the difficulty and expense of building these imagers, at most only a few two-dimensional projections images will be available to reconstruct the three-dimensional (3D) sources. In this paper, we present a technique that has been developed for the 3D reconstruction of neutron, gamma-ray, and x-ray sources from a minimal number of 2D projections using spherical harmonics decomposition. We present the detailed algorithms used for this characterization and the results of reconstructed sources from experimental neutron and x-ray data collected at OMEGA and NIF.

Neutron diffraction on pulsed sources

International Nuclear Information System (INIS)

Aksenov, V.L.; Balagurov, A.M.

2016-01-01

The possibilities currently offered and major scientific problems solved by time-of-flight neutron diffraction are reviewed. The reasons for the rapid development of the method over the last two decades has been mainly the emergence of third generation pulsed sources with a MW time-averaged power and advances in neutron-optical devices and detector systems. The paper discusses some historical aspects of time-of-flight neutron diffraction and examines the contribution to this method by F.L.Shapiro whose 100th birth anniversary was celebrated in 2015. The state of the art with respect to neutron sources for studies on output beams is reviewed in a special section. [ru

Isotopic neutron sources for neutron activation analysis

International Nuclear Information System (INIS)

Hoste, J.

1988-06-01

This User's Manual is an attempt to provide for teaching and training purposes, a series of well thought out demonstrative experiments in neutron activation analysis based on the utilization of an isotopic neutron source. In some cases, these ideas can be applied to solve practical analytical problems. 19 refs, figs and tabs

A Project for High Fluence 14 MeV Neutron Source

CERN Document Server

Pillon, Mario; Pizzuto, Aldo; Pietropaolo, Antonino

2014-01-01

The international community agrees on the importance to build a large facility devoted to test and validate materials to be used in harsh neutron environments. Such a facility, proposed by ENEA , reconsiders a previous study known as “Sorgentina” but takes into account new technological development so far attained. The “New Sorgentina” Fusion Source (NSFS) project is based upon an intense D - T 14 MeV neutron source achievable with T and D ion beams impinging on 2 m radius rotating target s . NSFS produces about 1 x10 13 n cm - 2 s - 1 over about 50 cm 3 . The NSFS facility will use the ion source and accelerating system technology developed for the Positive Ion Injectors (PII) used to heat the plasma in the fusion experiments,. NSFS, to be intended as an European facility, may be realized in a few years, once provided a preliminary technological program devote to study the operation of the ion source in continuous mode, target h eat loading/ removal, target and tritium handling, inventory as well as ...

Intense neutron sources for cancer treatment

International Nuclear Information System (INIS)

Anon.

1977-01-01

Significant progress has been made in the development of small, solid-target, pulsed neutron sources for nuclear weapons applications. The feasibility of using this type of neutron source for cancer treatment is discussed. Plans for fabrication and testing of such a source is briefly described

Pulsed thermal neutron source at the fast neutron generator.

Science.gov (United States)

Tracz, Grzegorz; Drozdowicz, Krzysztof; Gabańska, Barbara; Krynicka, Ewa

2009-06-01

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.

The Advanced Neutron Source

International Nuclear Information System (INIS)

Hayter, J.B.

1989-01-01

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 (φ th ∼ 9·10 19 m -2 ·s -1 ) accompanied by extensive and comprehensive equipment and facilities for neutron-based research. 5 refs., 5 figs

Neutronic performance issues for the Spallation Neutron Source moderators

International Nuclear Information System (INIS)

Iverson, E.B.; Murphy, B.D.

2001-01-01

We continue to develop the neutronic models of the Spallation Neutron Source target station and moderators in order to better predict the neutronic performance of the system as a whole and in order to better optimize that performance. While we are not able to say that every model change leads to more intense neutron beams being predicted, we do feel that such changes are advantageous in either performance or in the accuracy of the prediction of performance. We have computationally and experimentally studied the neutronics of hydrogen-water composite moderators such as are proposed for the SNS Project. In performing these studies, we find that the composite moderator, at least in the configuration we have examined, does not provide performance characteristics desirable for the instruments proposed and being designed for this neutron scattering facility. The pulse width as a function of energy is significantly broader than for other moderators, limiting attainable resolution-bandwidth combinations. Furthermore, there is reason to expect that higher-energy (0.1-1 eV) applications will be significantly impacted by bimodal pulse shapes requiring enormous effort to parameterize. As a result of these studies, we have changed the SNS design, and will not use a composite moderator at this time. We have analyzed the depletion of a gadolinium poison plate in a hydrogen moderator at the Spallation Neutron Source, and found that conventional poison thicknesses will be completely unable to last the desired component lifetime of three operational years. A poison plate 300-600 μm thick will survive for the required length of time, but will somewhat degrade the intensity (by as much as 15% depending on neutron energy) and the consistency of the neutron source performance. Our results should scale fairly easily to other moderators on this or any other spallation source. While depletion will be important for all highly-absorbing materials in high-flux regions, we feel it likely that

Plasma phenomenology in astrophysical systems: Radio-sources and jets

International Nuclear Information System (INIS)

Montani, Giovanni; Petitta, Jacopo

2014-01-01

We review the plasma phenomenology in the astrophysical sources which show appreciable radio emissions, namely Radio-Jets from Pulsars, Microquasars, Quasars, and Radio-Active Galaxies. A description of their basic features is presented, then we discuss in some details the links between their morphology and the mechanisms that lead to the different radio-emissions, investigating especially the role played by the plasma configurations surrounding compact objects (Neutron Stars, Black Holes). For the sake of completeness, we briefly mention observational techniques and detectors, whose structure set them apart from other astrophysical instruments. The fundamental ideas concerning angular momentum transport across plasma accretion disks—together with the disk-source-jet coupling problem—are discussed, by stressing their successes and their shortcomings. An alternative scenario is then inferred, based on a parallelism between astrophysical and laboratory plasma configurations, where small-scale structures can be found. We will focus our attention on the morphology of the radio-jets, on their coupling with the accretion disks and on the possible triggering phenomena, viewed as profiles of plasma instabilities

Effects of neutron spectrum and external neutron source on neutron multiplication parameters in accelerator-driven system

International Nuclear Information System (INIS)

Shahbunder, Hesham; Pyeon, Cheol Ho; Misawa, Tsuyoshi; Lim, Jae-Yong; Shiroya, Seiji

2010-01-01

The neutron multiplication parameters: neutron multiplication M, subcritical multiplication factor k s , external source efficiency φ*, play an important role for numerical assessment and reactor power evaluation of an accelerator-driven system (ADS). Those parameters can be evaluated by using the measured reaction rate distribution in the subcritical system. In this study, the experimental verification of this methodology is performed in various ADS cores; with high-energy (100 MeV) proton-tungsten source in hard and soft neutron spectra cores and 14 MeV D-T neutron source in soft spectrum core. The comparison between measured and calculated multiplication parameters reveals a maximum relative difference in the range of 6.6-13.7% that is attributed to the calculation nuclear libraries uncertainty and accuracy for energies higher than 20 MeV and also dependent on the reaction rate distribution position and count rates. The effects of different core neutron spectra and external neutron sources on the neutron multiplication parameters are discussed.

Neutron dosimetry at SLAC: Neutron sources and instrumentation

International Nuclear Information System (INIS)

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

1991-10-01

This report summarizes in detail the dosimetric characteristics of the five radioisotopic type neutron sources ( 238 PuBe, 252 Cf, 238 PuB, 238 PuF 4 , and 238 PuLi) and the neutron instrumentation (moderated BF 3 detector, Anderson-Braun (AB) detector, AB remmeter, Victoreen 488 Neutron Survey Meter, Beam Shut-Off Ionization Chamber, 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

Neutron measurements as fusion plasma diagnostics

International Nuclear Information System (INIS)

Nishitani, Takeo; Hoek, M.

1993-01-01

Neutron measurements play important roles as the diagnostics of many aspects of the plasma in large tokamak devices such as JT-60U and JET. In the d-d discharges of JT-60U, the most important application of the neutron measurement is the investigation of the fusion performance using fission chambers. The ion velocity distribution function, and the triton slowing down are investigated by the neutron spectrometer and the 14 MeV neutron detector, respectively. TANSY is a combined proton-recoil and neutron time-of flight spectrometer for 14 MeV neutrons to be used during the d-t phase at JET. The detection principle is based on the measurements of the flight time of a scattered initial neutron and the energy of a corresponding recoil proton. The scattering medium is a polyethylene foil. The resolution and efficiency, using a thin foil (0.95 mg/cm 2 ), is 155 keV and 1.4x10 -5 cm 2 , respectively. (author)

Compact neutron generator development and applications

International Nuclear Information System (INIS)

Leung, Ka-Ngo; Reijonen, Jani; Gicquel, Frederic; Hahto, Sami; Lou, Tak-Pui

2004-01-01

The Plasma and Ion Source Technology Group at the Lawrence Berkeley National Laboratory has been engaging in the development of high yield compact neutron generators for the last ten years. Because neutrons in these generators are formed by using either D-D, T-T or D-T fusion reaction, one can produce either mono-energetic (2.4 MeV or 14 MeV) or white neutrons. All the neutron generators being developed by our group utilize 13.5 MHz RF induction discharge to produce a pure deuterium or a mixture of deuterium-tritium plasma. As a result, ion beams with high current density and almost pure atomic ions can be extracted from the plasma source. The ion beams are accelerated to ∼100 keV and neutrons are produced when the beams impinge on a titanium target. Neutron generators with different configurations and sizes have been designed and tested at LBNL. Their applications include neutron activation analysis, oil-well logging, boron neutron capture therapy, brachytherapy, cargo and luggage screening. A novel small point neutron source has recently been developed for radiography application. The source size can be 2 mm or less, making it possible to examine objects with sharper images. The performance of these neutron generators will be described in this paper

Method for controlling an accelerator-type neutron source, and a pulsed neutron source

International Nuclear Information System (INIS)

Givens, W.W.

1991-01-01

The patent deals with an accelerator-type neutron source which employs a target, an ionization section and a replenisher for supplying accelerator gas. A positive voltage pulse is applied to the ionization section to produce a burst of neutrons. A negative voltage pulse is applied to the ionization section upon the termination of the positive voltage pulse to effect a sharp cut-off to the burst of neutrons. 4 figs

Thermal-hydraulic studies of the Advanced Neutron Source cold source

International Nuclear Information System (INIS)

Williams, P.T.; Lucas, A.T.

1995-08-01

The Advanced Neutron Source (ANS), in its conceptual design phase at Oak Ridge National Laboratory, was to be a user-oriented neutron research facility producing the most intense steady-state flux of thermal and cold neutrons in the world. Among its many scientific applications, the production of cold neutrons was a significant research mission for the ANS. The cold neutrons come from two independent cold sources positioned near the reactor core. Contained by an aluminum alloy vessel, each cold source is a 410-mm-diam sphere of liquid deuterium that functions both as a neutron moderator and a cryogenic coolant. With nuclear heating of the containment vessel and internal baffling, steady-state operation requires close control of the liquid deuterium flow near the vessel's inner surface. Preliminary thermal-hydraulic analyses supporting the cold source design were performed with heat conduction simulations of the vessel walls and multidimensional computational fluid dynamics simulations of the liquid deuterium flow and heat transfer. This report presents the starting phase of a challenging program and describes the cold source conceptual design, the thermal-hydraulic feasibility studies of the containment vessel, and the future computational and experimental studies that were planned to verify the final design

Self characterization of a coded aperture array for neutron source imaging

Energy Technology Data Exchange (ETDEWEB)

Volegov, P. L., E-mail: volegov@lanl.gov; Danly, C. R.; Guler, N.; Merrill, F. E.; Wilde, C. H. [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States); Fittinghoff, D. N. [Livermore National Laboratory, Livermore, California 94550 (United States)

2014-12-15

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 stagnation stage of inertial confinement fusion implosions. Since the neutron source is small (∼100 μm) and neutrons are deeply penetrating (>3 cm) in all materials, the apertures used to achieve the desired 10-μm resolution are 20-cm long, triangular tapers machined in gold foils. These gold foils are stacked to form an array of 20 apertures for pinhole imaging and three apertures for penumbral imaging. These apertures must be precisely aligned to accurately place the field of view of each aperture at the design location, or the location of the field of view for each aperture must be measured. In this paper we present a new technique that has been developed for the measurement and characterization of the precise location of each aperture in the array. We present the detailed algorithms used for this characterization and the results of reconstructed sources from inertial confinement fusion implosion experiments at NIF.

Pulsed neutron source well logging system

International Nuclear Information System (INIS)

Dillingham, M.E.

1975-01-01

A pulsed neutron source arrangement is provided in which a sealed cylindrical chamber encloses a rotatable rotor member carrying a plurality of elongated target strips of material which emits neutrons when bombarded with alpha particles emitted by the plurality of source material strips. The rotor may be locked in a so-called ON position by an electromagnetic clutch drive mechanism controllable from the earth's surface so as to permit the making of various types of logs utilizing a continuously emitting neutron source. (Patent Office Record)

Neutron dosimetry at SLAC: Neutron sources and instrumentation

Energy Technology Data Exchange (ETDEWEB)

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

1991-10-01

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.

An accelerator based steady state neutron source

International Nuclear Information System (INIS)

Burke, R.J.; Johnson, D.L.

1985-01-01

Using high current, c.w. linear accelerator technology, a spallation neutron source can achieve much higher average intensities than existing or proposed pulsed spallation sources. With about 100 mA of 300 MeV protons or deuterons, the Accelerator Based Neutron Research Facility (ABNR) would initially achieve the 10 16 n/cm 2 .s thermal flux goal of the advanced steady state neutron source, and upgrading could provide higher steady state fluxes. The relatively low ion energy compared to other spallation sources has an important impact on R and D requirements as well as capital cost, for which a range of $300-450M is estimated by comparison to other accelerator-based neutron source facilities. The source is similar to a reactor source in most respects. It has some higher energy neutrons but fewer gamma rays, and the moderator region is free of many of the design constraints of a reactor, which helps to implement sources for various neutron energy spectra, many beam tubes, etc. With the development of multi-beam concept and the basis for currents greater than 100 mA that is assumed in the R and D plan, the ABNR would serve many additional uses, such as fusion materials development, production of proton-rich isotopes, and other energy and defense program needs

Neutron scattering instruments for the Spallation Neutron Source (SNS)

International Nuclear Information System (INIS)

Crawford, R.K.; Fornek, T.; Herwig, K.W.

1998-01-01

The Spallation Neutron Source (SNS) is a 1 MW pulsed spallation source for neutron scattering planned for construction at Oak Ridge National Laboratory. This facility is being designed as a 5-laboratory collaboration project. This paper addresses the proposed facility layout, the process for selection and construction of neutron scattering instruments at the SNS, the initial planning done on the basis of a reference set of ten instruments, and the plans for research and development (R and D) to support construction of the first ten instruments and to establish the infrastructure to support later development and construction of additional instruments

Summary of alpha-neutron sources in GADRAS

International Nuclear Information System (INIS)

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

2012-01-01

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.

Anisotropy of neutron sources of Neutron Metrology Laboratory, IRD, Brazil

International Nuclear Information System (INIS)

Silva, A.C.F.; Silva, F.S.; Leite, S.P.; Creazolla, P.G; Patrão, K.C.S.; Fonseca, E.S. da; Fernandes, S.S.; Pereira, W.W.

2017-01-01

The anisotropy measurements have as main objective to define the emission of the radiation by different angles of an encapsulated neutron source. The measurements were performed using a Long Accuracy Counter (PLC) Detector in the Low Dispersion Room of the LNMRI / IRD with different neutron sources. Each measurement was made using a support for the source, emulated through an arduino system to rotate it. The carrier is marked with a variation of 5 °, ranging from 0 ° to 360 °, for the work in question only half, 0 ° to 180 ° is used for a total of nineteen steps. In this paper three sources of "2"4"1AmBe (α, n) 5.92 GBq (16 Ci) were used, neutron sources having the following dimensions: 105 mm in height and 31 mm in diameter. The PLC was positioned at a distance of 2 meters from the neutron source and has a radius of 15 cm for the detection area. The anisotropy factor of the "2"4"1AmBe source was 17%. The results in this work will focus mainly on the area of radioprotection and studies that will improve the process of routine measurements in laboratories and instrument calibrations. (author)

Neutron localization measurements from a two-gun plasma focus device

International Nuclear Information System (INIS)

Yeh, T.R.; Wen, M.; Tzeng, C.C.; Shang, D.J.; Yeh, C.K.; Wu, K.S.; Kuo, Y.Y.; Hou, W.S.

1989-01-01

The simultaneous formation of the two deuterium plasma foci has been reported recently by Hou, W.S., et al, in Procs I.E.E.E. Int. Conf. on Plasma Science, 1986, 87, in a Mather type two-gun plasma focus assembly with maximum bank energy of ∼700 kJ. In addition, these plasmas will evolve and then produce a disk-shaped plasma in the middle of the two plasma foci. Soft X-ray filter techniques which allow measurements of the electron temperature at both pinch points and the middle point yielded a few hundred eV for these three regions. Neutron localization measurements which were carried out with a collimator and a scintillator-fiber-photomultiplier assembly indicate that an enhancement of ∼80% in neutron yield is observed in the middle region as the separation between two electrodes is 9.1 cm. Further experimental evidence shows that the neutron production in the middle region is the result of the beam-beam interaction in nature. (author)

Recent advances in laser-driven neutron sources

Science.gov (United States)

Alejo, A.; Ahmed, H.; Green, A.; Mirfayzi, S. R.; Borghesi, M.; Kar, S.

2016-11-01

Due to the limited number and high cost of large-scale neutron facilities, there has been a growing interest in compact accelerator-driven sources. In this context, several potential schemes of laser-driven neutron sources are being intensively studied employing laser-accelerated electron and ion beams. In addition to the potential of delivering neutron beams with high brilliance, directionality and ultra-short burst duration, a laser-driven neutron source would offer further advantages in terms of cost-effectiveness, compactness and radiation confinement by closed-coupled experiments. Some of the recent advances in this field are discussed, showing improvements in the directionality and flux of the laser-driven neutron beams.

Neutron sources: Present practice and future potential

International Nuclear Information System (INIS)

Cierjacks, S.; Smith, A.B.

1988-01-01

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-producing efficiency and power-handling capabilities. The status of underlying neutron-producing reactions is summarized. The present and future use of neutron sources in: fundamental neutron-nuclear research, nuclear data acquisition, materials damage studies, engineering tests, and biomedical applications are discussed. Emphasis is given to current status, near-term advances well within current technology, and to long-range projections. 90 refs., 4 figs

Dynamically Polarized Sample for Neutron Scattering At the Spallation Neutron Source

International Nuclear Information System (INIS)

Pierce, Josh; Zhao, J. K.; Crabb, Don

2009-01-01

The recently constructed Spallation Neutron Source at the Oak Ridge National Laboratory is quickly becoming the world's leader in neutron scattering sciences. In addition to the world's most intense pulsed neutron source, we are continuously constructing state of the art neutron scattering instruments as well as sample environments to address today and tomorrow's challenges in materials research. The Dynamically Polarized Sample project at the SNS is aimed at taking maximum advantage of polarized neutron scattering from polarized samples, especially biological samples that are abundant in hydrogen. Polarized neutron scattering will allow us drastically increase the signal to noise ratio in experiments such as neutron protein crystallography. The DPS project is near completion and all key components have been tested. Here we report the current status of the project.

Status of ITER neutron diagnostic development

International Nuclear Information System (INIS)

Sasao, M.; Krasilnikov, A.V.; Kaschuck, Yu.A.; Nishitani, T.; Batistoni, P.; Zaveryaev, V.S.; Popovichev, S.; Jarvis, O.N.; Iguchi, T.; Kaellne, J.; Fiore, C.L.; Roquemore, A.L.; Heidbrink, W.W.; Fisher, R.; Gorini, G.; Donne, A.J.H.; Costley, A.E.; Walker, C.I.

2005-01-01

Due to the high neutron yield and the large plasma size many ITER plasma parameters such as fusion power, power density, ion temperature, fast ion energy and their spatial distributions in the plasma core can be well measured by various neutron diagnostics. Neutron diagnostic systems under consideration and development for ITER include: radial and vertical neutron cameras (RNC and VNC), internal and external neutron flux monitors, neutron activation systems and neutron spectrometers. The two-dimensional neutron source strength and spectral measurements can be provided by the combined RNC and VNC. The neutron flux monitors need to meet the ITER requirement of time-resolved measurements of the neutron source strength and can provide the signals necessary for real-time control of the ITER fusion power. Compact and high throughput neutron spectrometers are under development. A concept for the absolute calibration of neutron diagnostic systems is proposed. The development, testing in existing experiments and the engineering integration of all neutron diagnostic systems into ITER are in progress and the main results are presented. (author)

Status of ITER neutron diagnostic development

Science.gov (United States)

Krasilnikov, A. V.; Sasao, M.; Kaschuck, Yu. A.; Nishitani, T.; Batistoni, P.; Zaveryaev, V. S.; Popovichev, S.; Iguchi, T.; Jarvis, O. N.; Källne, J.; Fiore, C. L.; Roquemore, A. L.; Heidbrink, W. W.; Fisher, R.; Gorini, G.; Prosvirin, D. V.; Tsutskikh, A. Yu.; Donné, A. J. H.; Costley, A. E.; Walker, C. I.

2005-12-01

Due to the high neutron yield and the large plasma size many ITER plasma parameters such as fusion power, power density, ion temperature, fast ion energy and their spatial distributions in the plasma core can be measured well by various neutron diagnostics. Neutron diagnostic systems under consideration and development for ITER include radial and vertical neutron cameras (RNC and VNC), internal and external neutron flux monitors (NFMs), neutron activation systems and neutron spectrometers. The two-dimensional neutron source strength and spectral measurements can be provided by the combined RNC and VNC. The NFMs need to meet the ITER requirement of time-resolved measurements of the neutron source strength and can provide the signals necessary for real-time control of the ITER fusion power. Compact and high throughput neutron spectrometers are under development. A concept for the absolute calibration of neutron diagnostic systems is proposed. The development, testing in existing experiments and the engineering integration of all neutron diagnostic systems into ITER are in progress and the main results are presented.

Status of ITER neutron diagnostic development

International Nuclear Information System (INIS)

Krasilnikov, A.V.; Sasao, M.; Kaschuck, Yu.A.; Nishitani, T.; Batistoni, P.; Zaveryaev, V.S.; Popovichev, S.; Iguchi, T.; Jarvis, O.N.; Kaellne, J.; Fiore, C.L.; Roquemore, A.L.; Heidbrink, W.W.; Fisher, R.; Gorini, G.; Prosvirin, D.V.; Tsutskikh, A.Yu.; Donne, A.J.H.; Costley, A.E.; Walker, C.I.

2005-01-01

Due to the high neutron yield and the large plasma size many ITER plasma parameters such as fusion power, power density, ion temperature, fast ion energy and their spatial distributions in the plasma core can be measured well by various neutron diagnostics. Neutron diagnostic systems under consideration and development for ITER include radial and vertical neutron cameras (RNC and VNC), internal and external neutron flux monitors (NFMs), neutron activation systems and neutron spectrometers. The two-dimensional neutron source strength and spectral measurements can be provided by the combined RNC and VNC. The NFMs need to meet the ITER requirement of time-resolved measurements of the neutron source strength and can provide the signals necessary for real-time control of the ITER fusion power. Compact and high throughput neutron spectrometers are under development. A concept for the absolute calibration of neutron diagnostic systems is proposed. The development, testing in existing experiments and the engineering integration of all neutron diagnostic systems into ITER are in progress and the main results are presented

Compact neutron generator

Science.gov (United States)

Leung, Ka-Ngo; Lou, Tak Pui

2005-03-22

A compact neutron generator has at its outer circumference a toroidal shaped plasma chamber in which a tritium (or other) plasma is generated. A RF antenna is wrapped around the plasma chamber. A plurality of tritium ion beamlets are extracted through spaced extraction apertures of a plasma electrode on the inner surface of the toroidal plasma chamber and directed inwardly toward the center of neutron generator. The beamlets pass through spaced acceleration and focusing electrodes to a neutron generating target at the center of neutron generator. The target is typically made of titanium tubing. Water is flowed through the tubing for cooling. The beam can be pulsed rapidly to achieve ultrashort neutron bursts. The target may be moved rapidly up and down so that the average power deposited on the surface of the target may be kept at a reasonable level. The neutron generator can produce fast neutrons from a T-T reaction which can be used for luggage and cargo interrogation applications. A luggage or cargo inspection system has a pulsed T-T neutron generator or source at the center, surrounded by associated gamma detectors and other components for identifying explosives or other contraband.

Ion source requirements for pulsed spallation neutron sources

International Nuclear Information System (INIS)

Alonso, J.R.

1995-10-01

The neutron scattering community has endorsed the need for a high- power (1 to 5 MW) accelerator-driven source of neutrons for materials research. Properly configured, the accelerator could produce very short (sub-microsecond) bursts of cold neutrons, said time structure offering advantages over the continuous flux from a reactor for a large class of experiments. The recent cancellation of the ANS reactor project has increased the urgency to develop a comprehensive strategy based on the best technological scenarios. Studies to date have built on the experience from ISIS (the 160 KW source in the UK), and call for a high-current (approx. 100 mA peak) H - source-linac combination injecting into one or more accumulator rings in which beam may be further accelerated. The 1 to 5 GeV proton beam is extracted in a single turn and brought to the target-moderator stations. The high current, high duty-factor, high brightness and high reliability required of the ion source present a very large challenge to the ion source community. A workshop held in Berkeley in October 1994, analyzed in detail the source requirements for proposed accelerator scenarios, the present performance capabilities of different H - source technologies, and identified necessary R ampersand D efforts to bridge the gap

Ion source development for uranium-logging neutron tube

International Nuclear Information System (INIS)

Bacon, F.M.; O'Hagan, J.B.

1977-03-01

Ion beam current and mass distributions have been measured for a Penning-type ion source in a uranium-logging neutron tube. For a discharge current of 1 A and gas pressure of 1.3 Pa, the beam current was about 65 mA and the mass distribution was 5 percent D + , 80 percent D 2 + , and 15 percent D 3 + . A demountable version of this source was built to determine how geometry changes could affect the ion beam current and mass distribution. A factor of three increase in beam current was achieved by decreasing the depth of the plasma expansion cup to zero. The only method by which the mass distribution was significantly modified was by dissociating the gas in the source with a hot tungsten filament. Atomic percentage was increased to 40 percent with a filament at about 3000 K

Development and characterization of a high yield transportable pulsed neutron source with efficient and compact pulsed power system

Energy Technology Data Exchange (ETDEWEB)

Verma, Rishi, E-mail: rishiv9@gmail.com, E-mail: rishiv@barc.gov.in; Mishra, Ekansh; Dhang, Prosenjit; Sagar, Karuna; Meena, Manraj; Shyam, Anurag [Energetics and Electromagnetics Division, Bhabha Atomic Research Centre Autonagar, Vishakapatnam 530012 (India)

2016-09-15

The results of characterization experiments carried out on a newly developed dense plasma focus device based intense pulsed neutron source with efficient and compact pulsed power system are reported. Its high current sealed pseudospark switch based low inductance capacitor bank with maximum stored energy of ∼10 kJ is segregated into four modules of ∼2.5 kJ each and it cumulatively delivers peak current in the range of 400 kA–600 kA (corresponding to charging voltage range of 14 kV–18 kV) in a quarter time period of ∼2 μs. The neutron yield performance of this device has been optimized by discretely varying deuterium filling gas pressure in the range of 6 mbar–11 mbar at ∼17 kV/550 kA discharge. At ∼7 kJ/8.5 mbar operation, the average neutron yield has been measured to be in the order of ∼4 × 10{sup 9} neutrons/pulse which is the highest ever reported neutron yield from a plasma focus device with the same stored energy. The average forward to radial anisotropy in neutron yield is found to be ∼2. The entire system is contained on a moveable trolley having dimensions 1.5 m × 1 m × 0.7 m and its operation and control (up to the distance of 25 m) are facilitated through optically isolated handheld remote console. The overall compactness of this system provides minimum proximity to small as well as large samples for irradiation. The major intended application objective of this high neutron yield dense plasma focus device development is to explore the feasibility of active neutron interrogation experiments by utilization of intense pulsed neutron sources.

Neutron beam design for low intensity neutron and gamma-ray radioscopy using small neutron sources

CERN Document Server

Matsumoto, T

2003-01-01

Two small neutron sources of sup 2 sup 5 sup 2 Cf and sup 2 sup 4 sup 1 Am-Be radioisotopes were used for design of neutron beams applicable to low intensity neutron and gamma ray radioscopy (LINGR). In the design, Monte Carlo code (MCNP) was employed to generate neutron and gamma ray beams suited to LINGR. With a view to variable neutron spectrum and neutron intensity, various arrangements were first examined, and neutron-filter, gamma-ray shield and beam collimator were verified. Monte Carlo calculations indicated that with a suitable filter-shield-collimator arrangement, thermal neutron beam of 3,900 ncm sup - sup 2 s sup - sup 1 with neutron/gamma ratio of 7x10 sup 7 , and 25 ncm sup - sup 2 s sup - sup 1 with very large neutron/gamma ratio, respectively, could be produced by using sup 2 sup 5 sup 2 Cf(122 mu g) and a sup 2 sup 4 sup 1 Am-Be(37GBq)radioisotopes at the irradiation port of 35 cm from the neutron sources.

Procedure for measurement of anisotropy factor for neutron sources

International Nuclear Information System (INIS)

Creazolla, Prycylla Gomes

2017-01-01

Radioisotope neutron sources allow the production of reference fields for calibration of neutron detectors for radiation protection and analysis purposes. When the emission rate of these sources is isotropic, no correction is necessary. However, variations in source encapsulation and in the radioactive material concentration produce differences in its neutron emission rate, relative to the source axis, this effect is called anisotropy. In this study, is describe a procedure for measuring the anisotropy factor of neutron sources performed in the Laboratório de Metrologia de Neutrons (LN) using a Precision Long Counter (PLC) detector. A measurement procedure that takes into account the anisotropy factor of neutron sources contributes to solve some issues, particularly with respect to the high uncertainties associated with neutron dosimetry. Thus, a bibliographical review was carried out based on international standards and technical regulations specific to the area of neutron fields, and were later reproduced in practice by means of the procedure for measuring the anisotropy factor in neutron sources of the LN. The anisotropy factor is determined as a function of the angle of 90° in relation to the cylindrical axis of the source. This angle is more important due to its high use in measurements and also of its higher neutron emission rate if compared with other angles. (author)

A dense plasma focus-based neutron source for a single-shot detection of illicit materials and explosives by a nanosecond neutron pulse

International Nuclear Information System (INIS)

Gribkov, V A; Latyshev, S V; Miklaszewski, R A; Chernyshova, M; Drozdowicz, K; Wiacek, U; Tomaszewski, K; Lemeshko, B D

2010-01-01

Recent progress in a single-pulse Nanosecond Impulse Neutron Investigation System (NINIS) intended for interrogation of hidden objects by means of measuring elastically scattered neutrons is presented in this paper. The method uses very bright neutron pulses having duration of the order of 10 ns only, which are generated by dense plasma focus (DPF) devices filled with pure deuterium or DT mixture as a working gas. The small size occupied by the neutron bunch in space, number of neutrons per pulse and mono-chromaticity (ΔE/E∼1%) of the neutron spectrum provides the opportunity to use a time-of-flight (TOF) technique with flying bases of about a few metres. In our researches we used DPF devices having bank energy in the range 2-7 kJ. The devices generate a neutron yield of the level of 10 8 -10 9 2.45 MeV and 10 10 -10 11 14 MeV neutrons per pulse with pulse duration ∼10-20 ns. TOF base in the tests was 2.2-18.5 m. We have demonstrated the possibility of registering of neutrons scattered by the substances under investigation-1 litre bottles with methanol (CH 3 OH), phosphoric (H 2 PO 4 ) and nitric (HNO 3 ) acids as well as a long object-a 1 m gas tank filled with deuterium at high pressure. It is shown that the above mentioned short TOF bases and relatively low neutron yields are enough to distinguish different elements' nuclei composing the substance under interrogation and to characterize the geometry of lengthy objects in some cases. The wavelet technique was employed to 'clean' the experimental data registered. The advantages and restrictions of the proposed and tested NINIS technique in comparison with other methods are discussed.

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

International Nuclear Information System (INIS)

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

2003-01-01

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

An Accelerator Neutron Source for BNCT

Energy Technology Data Exchange (ETDEWEB)

Blue, Thomas, E

2006-03-14

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.

An Accelerator Neutron Source for BNCT

International Nuclear Information System (INIS)

Blue, Thomas E.

2006-01-01

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 technologically 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

Characteristics of polyethylene-moderated 252Cf neutron sources

International Nuclear Information System (INIS)

Alejnikov, V.E.; Beskrovnaya, L.G.; Florko, B.V.

2000-01-01

Polyethylene-moderated 252 Cf neutron sources were designed to produce neutron reference fields' spectra that simulate the spectra observed in the workplaces within nuclear reactors and accelerators. The paper describes the neutron sources and fields. Neutron spectra were calculated by Monte Carlo method and compared with experimental data

Fissile mass estimation by pulsed neutron source interrogation

Energy Technology Data Exchange (ETDEWEB)

Israelashvili, I., E-mail: israelashvili@gmail.com [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel); Dubi, C.; Ettedgui, H.; Ocherashvili, A. [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel); Pedersen, B. [Nuclear Security Unit, Institute for Transuranium Elements, Joint Research Centre, Via E. Fermi, 2749, 21027 Ispra (Italy); Beck, A. [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel); Roesgen, E.; Crochmore, J.M. [Nuclear Security Unit, Institute for Transuranium Elements, Joint Research Centre, Via E. Fermi, 2749, 21027 Ispra (Italy); Ridnik, T.; Yaar, I. [Nuclear Research Center of the Negev, P.O.B 9001, Beer Sheva 84190 (Israel)

2015-06-11

Passive methods for detecting correlated neutrons from spontaneous fissions (e.g. multiplicity and SVM) are widely used for fissile mass estimations. These methods can be used for fissile materials that emit a significant amount of fission neutrons (like plutonium). Active interrogation, in which fissions are induced in the tested material by an external continuous source or by a pulsed neutron source, has the potential advantages of fast measurement, alongside independence of the spontaneous fissions of the tested fissile material, thus enabling uranium measurement. Until recently, using the multiplicity method, for uranium mass estimation, was possible only for active interrogation made with continues neutron source. Pulsed active neutron interrogation measurements were analyzed with techniques, e.g. differential die away analysis (DDA), which ignore or implicitly include the multiplicity effect (self-induced fission chains). Recently, both, the multiplicity and the SVM techniques, were theoretically extended for analyzing active fissile mass measurements, made by a pulsed neutron source. In this study the SVM technique for pulsed neutron source is experimentally examined, for the first time. The measurements were conducted at the PUNITA facility of the Joint Research Centre in Ispra, Italy. First promising results, of mass estimation by the SVM technique using a pulsed neutron source, are presented.

Research on background neutron of 226Ra γ source

International Nuclear Information System (INIS)

Ji Changsong

1996-01-01

This work studies the background neutron emission of 226 Ra γ source: the mechanism of resulting in background neutron is studied; a thesis that the (α, n) type reaction on Radium carriers Cl or Br is the main source of creating background neutron emission of 226 Ra γ source has been proposed and certificated; a proposal of substitution of Cl carrier by Br in radium source produced in China in order to reduce background neutron emission is put forward. A result to reduce the background neutron from 96.4 neutrons/4πsmgRa to 6.1 neutrons/4πsmgRa is obtained

The new Munich neutron source

International Nuclear Information System (INIS)

Herrmann, W.A.

1998-01-01

The Munich FRM II neutron source currently under construction is to replace the FRM I research reactor in Munich, also known as 'atomic egg'. The project is executed by the Free State of Bavaria as a construction project of the Munich Technical University and managed by the University. As main contractor for the construction project, Siemens AG is also co-applicant in the licensing procedure under the Atomic Energy Act for the construction phase. The project is carried out to build a modern high flux neutron source required for a broad range of applications in research and technology mainly with thermal and cold neutrons. The 'neutron gap' existing in Germany is to be closed with the FRM II. As a national research installation, the FRM II is available to all interested scientists from a variety of disciplines. (orig.) [de

Neutron generator tube ion source control

International Nuclear Information System (INIS)

Bridges, J.R.

1982-01-01

A system is claimed for controlling the output of a neutron generator tube of the deuterium-tritium accelerator type and having an ion source to produce sharply defined pulses of neutrons for well logging use. It comprises: means for inputting a relatively low voltage input control pulse having a leading edge and a trailing edge; means, responsive to the input control pulse, for producing a relatively high voltage ion source voltage pulse after receipt of the input pulse; and means, responsive to the input control pulse, for quenching, after receipt of the input pulse, the ion source control pulse, thereby providing a sharply time defined neutron output from the generator tube

Research on neutron source multiplication method in nuclear critical safety

International Nuclear Information System (INIS)

Zhu Qingfu; Shi Yongqian; Hu Dingsheng

2005-01-01

The paper concerns in the neutron source multiplication method research in nuclear critical safety. Based on the neutron diffusion equation with external neutron source the effective sub-critical multiplication factor k s is deduced, and k s is different to the effective neutron multiplication factor k eff in the case of sub-critical system with external neutron source. The verification experiment on the sub-critical system indicates that the parameter measured with neutron source multiplication method is k s , and k s is related to the external neutron source position in sub-critical system and external neutron source spectrum. The relation between k s and k eff and the effect of them on nuclear critical safety is discussed. (author)

Ion source requirements for pulsed spallation neutron sources

International Nuclear Information System (INIS)

Alonso, J.R.

1996-01-01

The neutron scattering community has endorsed the need for a high-power (1 to 5 MW) accelerator-driven source of neutrons for materials research. Properly configured, the accelerator could produce very short (sub-microsecond) bursts of cold neutrons, said time structure offering advantages over the continuous flux from a reactor for a large class of experiments. The recent cancellation of the ANS reactor project has increased the urgency to develop a comprehensive strategy based on the best technological scenarios. Studies to date have built on the experience from ISIS (the 160 kW source in the UK), and call for a high-current (approx. 100 mA peak) H - source-linac combination injecting into one or more accumulator rings in which beam may be further accelerated. The 1 to 5 GeV proton beam is extracted in a single turn and brought to the target-moderator stations. The high current, high duty-factor, high brightness and high reliability required of the ion source present a very large challenge to the ion source community. A workshop held in Berkeley in October 1994, analyzed in detail the source requirements for proposed accelerator scenarios, the present performance capabilities of different H - source technologies, and identified necessary R ampersand D efforts to bridge the gap. copyright 1996 American Institute of Physics

Neutron angular distribution in a plasma focus obtained using nuclear track detectors.

Science.gov (United States)

Castillo-Mejía, F; Herrera, J J E; Rangel, J; Golzarri, J I; Espinosa, G

2002-01-01

The dense plasma focus (DPF) is a coaxial plasma gun in which a high-density, high-temperature plasma is obtained in a focused column for a few nanoseconds. When the filling gas is deuterium, neutrons can be obtained from fusion reactions. These are partially due to a beam of deuterons which are accelerated against the background hot plasma by large electric fields originating from plasma instabilities. Due to a beam-target effect, the angular distribution of the neutron emission is anisotropic, peaked in the forward direction along the axis of the gun. The purpose of this work is to illustrate the use of CR-39 nuclear track detectors as a diagnostic tool in the determination of the time-integrated neutron angular distribution. For the case studied in this work, neutron emission is found to have a 70% contribution from isotropic radiation and a 30% contribution from anisotropic radiation.

Neutronic Design Calculations on Moderators for the Spallation Neutron Source (SNS)

International Nuclear Information System (INIS)

Murphy, D.B.

1999-01-01

The Spallation Neutron Source (SNS) to be built at the Oak Ridge National Laboratory will provide an intense source of neutrons for a large variety of experiments. It consists of a high-energy (1-GeV) and high-power (∼1-MW) proton accelerator, an accumulator ring, together with a target station and an experimental area. In the target itself, the proton beam will produce neutrons via the spallation process and these will be converted to low-energy ( 2 O moderators. Extensive engineering design work has been conducted on the moderator vessels. For our studies we have produced realistic neutronic representations of these moderators. We report on neutronic studies conducted on these representations of the moderators using Monte Carlo simulation techniques

New scientific horizons with pulsed spallation neutron sources

International Nuclear Information System (INIS)

Carlile, C.J.; Finney, J.L.

1991-01-01

Pulsed spallation sources are not just another way of producing neutrons: the time structure of the neutron pulse has consequences which allow new scientific areas to be investigated and traditional areas to be explored afresh. In addition to the high epithermal neutron component traditionally associated with pulsed sources the recent development of cold neutron techniques at ISIS illustrates that very high energy and momentum resolutions can be achieved on pulsed sources over a surprisingly wide range. (orig.)

Neutron production enhancements for the Intense Pulsed Neutron Source.

Energy Technology Data Exchange (ETDEWEB)

Iverson, E. B.

1999-01-04

The Intense Pulsed Neutron Source (IPNS) was the first high energy spallation neutron source in the US dedicated to materials research. It has operated for sixteen years, and in that time has had a very prolific record concerning the development of new target and moderator systems for pulsed spallation sources. IPNS supports a very productive user program on its thirteen instruments, which are oversubscribed by more than two times, meanwhile having an excellent overall reliability of 95%. Although the proton beam power is relatively low at 7 kW, the target and moderator systems are very efficient. The typical beam power which gives an equivalent flux for long-wavelength neutrons is about 60 kW, due to the use of a uranium target and liquid and solid methane moderators, precluded at some sources due to a higher accelerator power. The development of new target and moderator systems is by no means stagnant at IPNS. They are presently considering numerous enhancements to the target and moderators that offer prospects for increasing the useful neutron production by substantial factors. Many of these enhancements could be combined, although their combined benefit has not yet been well established. Meanwhile, IPNS is embarking on a coherent program of study concerning these improvements and their possible combination and implementation. Moreover, any improvements accomplished at IPNS would immediately increase the performance of IPNS instruments.

Neutron production enhancements for the Intense Pulsed Neutron Source

International Nuclear Information System (INIS)

Iverson, E. B.

1999-01-01

The Intense Pulsed Neutron Source (IPNS) was the first high energy spallation neutron source in the US dedicated to materials research. It has operated for sixteen years, and in that time has had a very prolific record concerning the development of new target and moderator systems for pulsed spallation sources. IPNS supports a very productive user program on its thirteen instruments, which are oversubscribed by more than two times, meanwhile having an excellent overall reliability of 95%. Although the proton beam power is relatively low at 7 kW, the target and moderator systems are very efficient. The typical beam power which gives an equivalent flux for long-wavelength neutrons is about 60 kW, due to the use of a uranium target and liquid and solid methane moderators, precluded at some sources due to a higher accelerator power. The development of new target and moderator systems is by no means stagnant at IPNS. They are presently considering numerous enhancements to the target and moderators that offer prospects for increasing the useful neutron production by substantial factors. Many of these enhancements could be combined, although their combined benefit has not yet been well established. Meanwhile, IPNS is embarking on a coherent program of study concerning these improvements and their possible combination and implementation. Moreover, any improvements accomplished at IPNS would immediately increase the performance of IPNS instruments

Small neutron sources as centers for innovation and science

International Nuclear Information System (INIS)

Baxter, D.V.

2009-01-01

The education and training of the next generation of scientists who will form the user base for the Spallation Neutron Source (SNS) remains a significant issue for the future success of this national facility. These scientists will be drawn from a wide variety of disciplines (physics, chemistry, biology, and engineering) and therefore the development of an effective interdisciplinary training program represents a significant challenge. In addition, effective test facilities to develop the full potential of pulsed neutron sources for science do not exist. Each of these problems represents a significant hurdle for the future health of neutron science in this country. An essential part of the solution to both problems is to get neutron sources of useful intensities into the hands of researchers and students at universities, where faculty can teach students about neutron production and the utility of neutrons for solving scientific problems. Due to a combination of developments in proton accelerator technology, neutron optics, cold neutron moderators, computer technology, and small-angle neutron scattering (SANS) instrumentation, it is now technically possible and cost effective to construct a pulsed cold neutron source suitable for use in a university setting and devoted to studies of nano structures in the fields of materials science, polymers, microemulsions, and biology. Such a source, based on (p,n) reactions in light nuclei induced by a few MeV pulsed proton beam coupled to a cold neutron moderator, would also be ideal for the study of a number of technical issues which are essential for the development of neutron science such as cold and perhaps ultracold neutron moderators, neutron optical devices, neutron detector technology, and transparent DAQ/user interfaces. At the Indiana University Cyclotron Facility (IUCF) we possess almost all of the required instrumentation and expertise to efficiently launch the first serious attempt to develop an intense pulsed cold

Cryogenic refrigeration for cold neutron sources

International Nuclear Information System (INIS)

Gistau-Baguer, Guy

1998-01-01

Neutron moderation by means of a fluid at cryogenic temperature is a very interesting way to obtain cold neutrons. Today, a number of nuclear research reactors are using this technology. This paper deals with thermodynamics and technology which are used for cooling Cold Neutron Sources

10 CFR 39.55 - Tritium neutron generator target sources.

Science.gov (United States)

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Tritium neutron generator target sources. 39.55 Section 39... Equipment § 39.55 Tritium neutron generator target sources. (a) Use of a tritium neutron generator target....77. (b) Use of a tritium neutron generator target source, containing quantities exceeding 1,110 GBg...

Options for the Delft advanced neutron source

International Nuclear Information System (INIS)

Gibcus, H.P.M.; Leege, P.F.A. de; Labohm, F.; Vries, J.W. de; Verkooijen, A.H.M.; Valko, J.; Feltes, W.; Heinecke, J.

2003-01-01

Results of feasibility studies are presented for options for an advanced neutron source for the Delft reactor including upgrading the HOR, a 2 MW pool-type research reactor at the Delft University of Technology. The primary utilisation of the HOR focuses on beam research applications with neutrons and positrons. The aim of being scientifically competitive in that research area requires a thermal neutron flux level of at least 1x10 14 n/cm 2 /s. The feasibility of an accelerator driven neutron source and upgrading the present core to a super compact core for reaching this goal has been investigated at large from a safety and operational point of view. For the upgraded core, a 3x3 fuel assembly arrangement and beryllium reflected at all sides was chosen. Figures on the system performance, including the merits of a cold neutron source application feeding the neutron guide system, are presented. (author)

Development of a D-D Neutron Generator

International Nuclear Information System (INIS)

Kim, In Jung; Jung, Hwa Dong; Park, Chang Su; Jung, Nam Suk; Jung, Soon Wook; Hwang, Y. S.; Choi, H. D.

2007-01-01

To enhance neutron yield, the ion source of the D-D neutron generator is replaced by a large current helicon plasma ion source. Current and energy of deuteron beam are increased, and hence neutron yield is enhanced. The maximum neutron yield is 2x10 8 n/s

New opportunities in neutron capture research using advanced pulsed neutron sources

International Nuclear Information System (INIS)

Bowman, C.D.

1987-08-01

The extraordinary neutron intensities available from the new spallation pulsed neutron sources open up exciting opportunities for basic and applied research in neutron nuclear physics. Prospective experiments are reviewed with particular attention to those with a strong connection to capture gamma-ray spectroscopy

Advances towards a portable pulsed source of neutrons and X-ray with energy of work close to 1 Joule

International Nuclear Information System (INIS)

Soto, Leopoldo; Pavez, C.; Moreno, Jose; Clausse, Alejandro; Barbaglia, Mario O.

2005-01-01

Plasma Focus devices are pulsed sources of X and neutron radiation from intense electrical discharges in deuterium. Classically these devices operate at energies between a few KJ to 1 MJ. In this work we present the design and feasibility studies of a Plasma Focus operating at energies close to 1 Joule. Experimental evidence of focalization is presented, and the optimum parameter relations at such low energies are discussed. The results indicate the device will be able to emit pulses about 1000 neutrons per J. (author) [es

Neutron source strength associated with FTR fuel

International Nuclear Information System (INIS)

Boroughs, G.L.; Bunch, W.L.; Johnson, D.L.

1975-01-01

The study presented shows the important effect of shelf life on the neutron source strength anticipated from fuel irradiated in the FTR. The neutron source strength will be enhanced appreciably by extended shelf lives. High neutron source strengths will also be associated with reprocessed LWR plutonium, which is expected to contain a greater abundance of the higher isotopes. The branching ratio and cross section of 241 Am is an important parameter that needs to be defined more precisely to establish calculated values with greater precision

An advanced fusion neutron source facility

International Nuclear Information System (INIS)

Smith, D.L.

1992-01-01

Accelerator-based 14-MeV-neutron sources based on modifications of the original Fusion Materials Irradiation Facility are currently under consideration for investigating the effects of high-fluence high-energy neutron irradiation on fusion-reactor materials. One such concept for a D-Li neutron source is based on recent advances in accelerator technology associated with the Continuous Wave Deuterium Demonstrator accelerator under construction at Argonne National Laboratory, associated superconducting technology, and advances in liquid-metal technology. In this paper a summary of conceptual design aspects based on improvements in technologies is presented

Future prospects of imaging at spallation neutron sources

International Nuclear Information System (INIS)

Strobl, M.

2009-01-01

The advent of state-of-the-art spallation neutron sources is a major step forward in efficient neutron production for most neutron scattering techniques. Although they provide lower time-averaged neutron flux than high flux reactor sources, advantage for different instrumental techniques can be derived from the pulsed time structure of the available flux, which can be translated into energy, respectively, wavelength resolution. Conventional neutron imaging on the other hand relies on an intense continuous beam flux and hence falls short in profiting from the new development. Nevertheless, some recently developed novel imaging techniques require and some can benefit from energy resolution. The impact of the emerging spallation sources on different imaging techniques has been investigated, ways to benefit will be identified (where possible) and prospects of future imaging instruments and possible options and layouts at a spallation neutron source will be discussed and outlined.

Neutron spectroscopy measurements of 14 MeV neutrons at unprecedented energy resolution and implications for deuterium-tritium fusion plasma diagnostics

Science.gov (United States)

Rigamonti, D.; Giacomelli, L.; Gorini, G.; Nocente, M.; Rebai, M.; Tardocchi, M.; Angelone, M.; Batistoni, P.; Cufar, A.; Ghani, Z.; Jednorog, S.; Klix, A.; Laszynska, E.; Loreti, S.; Pillon, M.; Popovichev, S.; Roberts, N.; Thomas, D.; Contributors, JET

2018-04-01

An accurate calibration of the JET neutron diagnostics with a 14 MeV neutron generator was performed in the first half of 2017 in order to provide a reliable measurement of the fusion power during the next JET deuterium-tritium (DT) campaign. In order to meet the target accuracy, the chosen neutron generator has been fully characterized at the Neutron Metrology Laboratory of the National Physical Laboratory (NPL), Teddington, United Kingdom. The present paper describes the measurements of the neutron energy spectra obtained using a high-resolution single-crystal diamond detector (SCD). The measurements, together with a new neutron source routine ‘ad hoc’ developed for the MCNP code, allowed the complex features of the neutron energy spectra resulting from the mixed D/T beam ions interacting with the T/D target nuclei to be resolved for the first time. From the spectral analysis a quantitative estimation of the beam ion composition has been made. The unprecedented intrinsic energy resolution (<1% full width at half maximum (FWHM) at 14 MeV) of diamond detectors opens up new prospects for diagnosing DT plasmas, such as, for instance, the possibility to study non-classical slowing down of the beam ions by neutron spectroscopy on ITER.

Neutron activation analysis: Modelling studies to improve the neutron flux of Americium-Beryllium source

Energy Technology Data Exchange (ETDEWEB)

Didi, Abdessamad; Dadouch, Ahmed; Tajmouati, Jaouad; Bekkouri, Hassane [Advanced Technology and Integration System, Dept. of Physics, Faculty of Science Dhar Mehraz, University Sidi Mohamed Ben Abdellah, Fez (Morocco); Jai, Otman [Laboratory of Radiation and Nuclear Systems, Dept. of Physics, Faculty of Sciences, Tetouan (Morocco)

2017-06-15

Americium–beryllium (Am-Be; n, γ) is a neutron emitting source used in various research fields such as chemistry, physics, geology, archaeology, medicine, and environmental monitoring, as well as in the forensic sciences. It is a mobile source of neutron activity (20 Ci), yielding a small thermal neutron flux that is water moderated. The aim of this study is to develop a model to increase the neutron thermal flux of a source such as Am-Be. This study achieved multiple advantageous results: primarily, it will help us perform neutron activation analysis. Next, it will give us the opportunity to produce radio-elements with short half-lives. Am-Be single and multisource (5 sources) experiments were performed within an irradiation facility with a paraffin moderator. The resulting models mainly increase the thermal neutron flux compared to the traditional method with water moderator.

Calibration of neutron detectors on the Joint European Torus.

Science.gov (United States)

Batistoni, Paola; Popovichev, S; Conroy, S; Lengar, I; Čufar, A; Abhangi, M; Snoj, L; Horton, L

2017-10-01

The present paper describes the findings of the calibration of the neutron yield monitors on the Joint European Torus (JET) performed in 2013 using a 252 Cf source deployed inside the torus by the remote handling system, with particular regard to the calibration of fission chambers which provide the time resolved neutron yield from JET plasmas. The experimental data obtained in toroidal, radial, and vertical scans are presented. These data are first analysed following an analytical approach adopted in the previous neutron calibrations at JET. In this way, a calibration function for the volumetric plasma source is derived which allows us to understand the importance of the different plasma regions and of different spatial profiles of neutron emissivity on fission chamber response. Neutronics analyses have also been performed to calculate the correction factors needed to derive the plasma calibration factors taking into account the different energy spectrum and angular emission distribution of the calibrating (point) 252 Cf source, the discrete positions compared to the plasma volumetric source, and the calibration circumstances. All correction factors are presented and discussed. We discuss also the lessons learnt which are the basis for the on-going 14 MeV neutron calibration at JET and for ITER.

Linac-driven spallation-neutron source

International Nuclear Information System (INIS)

Jason, A.J.

1995-01-01

Strong interest has arisen in accelerator-driven spallation-neutron sources that surpass existing facilities (such as ISIS at Rutherford or LANSCE at Los Alamos) by more than an order of magnitude in beam power delivered to the spallation target. The approach chosen by Los Alamos (as well as the European Spallation Source) provides the full beam energy by acceleration in a linac as opposed to primary acceleration in a synchrotron or other circular device. Two modes of neutron production are visualized for the source. A short-pulse mode produces 1 MW of beam power (at 60 pps) in pulses, of length less than 1 ms, by compression of the linac macropulse through multi-turn injection in an accumulator ring. A long-pulse mode produces a similar beam power with 1-ms-long pulses directly applied to a target. This latter mode rivals the performance of existing reactor facilities to very low neutron energies. Combination with the short-pulse mode addresses virtually all applications

Low dimensional neutron moderators for enhanced source brightness

DEFF Research Database (Denmark)

Mezei, Ferenc; Zanini, Luca; Takibayev, Alan

2014-01-01

In a recent numerical optimization study we have found that liquid para-hydrogen coupled cold neutron moderators deliver 3–5 times higher cold neutron brightness at a spallation neutron source if they take the form of a flat, quasi 2-dimensional disc, in contrast to the conventional more voluminous...... for cold neutrons. This model leads to the conclusions that the optimal shape for high brightness para-hydrogen neutron moderators is the quasi 1-dimensional tube and these low dimensional moderators can also deliver much enhanced cold neutron brightness in fission reactor neutron sources, compared...... to the much more voluminous liquid D2 or H2 moderators currently used. Neutronic simulation calculations confirm both of these theoretical conclusions....

Neutronic study of spherical cold-neutron sources composed of liquid hydrogen and liquid deuterium

CERN Document Server

Matsuo, Y; Nagaya, Y

2003-01-01

Using the cross-section model for neutron scattering in liquid H sub 2 and D sub 2 , a neutron transport analysis is performed for spherical cold-neutron sources composed of either para H sub 2 , normal H sub 2 or normal D sub 2. A special effort is made to generate a set of energy-averaged cross-sections (80 group constants between 0.1 mu eV and 10 eV) for liquid H sub 2 and D sub 2 at melting and boiling points. A number of conclusions on the spherical cold-neutron source configurations are drawn. It is especially shown that the highest cold-neutron flux is obtainable from the normal D sub 2 source with a radius of about 50 cm, while the normal- and para-H sub 2 sources with radii around 3-4 cm produce maximum cold-neutron fluxes at the center.

Calculations of accelerator-based neutron sources characteristics

International Nuclear Information System (INIS)

Tertytchnyi, R.G.; Shorin, V.S.

2000-01-01

Accelerator-based quasi-monoenergetic neutron sources (T(p,n), D(d;n), T(d;n) and Li (p,n)-reactions) are widely used in experiments on measuring the interaction cross-sections of fast neutrons with nuclei. The present work represents the code for calculation of the yields and spectra of neutrons generated in (p, n)- and ( d; n)-reactions on some targets of light nuclei (D, T; 7 Li). The peculiarities of the stopping processes of charged particles (with incident energy up to 15 MeV) in multilayer and multicomponent targets are taken into account. The code version is made in terms of the 'SOURCE,' a subroutine for the well-known MCNP code. Some calculation results for the most popular accelerator- based neutron sources are given. (authors)

Study of a spherical torus based volumetric neutron source for nuclear technology testing and development

International Nuclear Information System (INIS)

Cheng, E.T.; Cerbone, R.J.; Sviatoslavsky, I.N.; Galambos, L.D.; Peng, Y.-K.M.

2000-01-01

A plasma based, deuterium and tritium (DT) fueled, volumetric 14 MeV neutron source (VNS) has been considered as a possible facility to support the development of the demonstration fusion power reactor (DEMO). It can be used to test and develop necessary fusion blanket and divertor components and provide sufficient database, particularly on the reliability of nuclear components necessary for DEMO. The VNS device can be complement to ITER by reducing the cost and risk in the development of DEMO. A low cost, scientifically attractive, and technologically feasible volumetric neutron source based on the spherical torus (ST) concept has been conceived. The ST-VNS, which has a major radius of 1.07 m, aspect ratio 1.4, and plasma elongation three, can produce a neutron wall loading from 0.5 to 5 MW m -2 at the outboard test section with a modest fusion power level from 38 to 380 MW. It can be used to test necessary nuclear technologies for fusion power reactor and develop fusion core components include divertor, first wall, and power blanket. Using staged operation leading to high neutron wall loading and optimistic availability, a neutron fluence of more than 30 MW year m -2 is obtainable within 20 years of operation. This will permit the assessments of lifetime and reliability of promising fusion core components in a reactor relevant environment. A full scale demonstration of power reactor fusion core components is also made possible because of the high neutron wall loading capability. Tritium breeding in such a full scale demonstration can be very useful to ensure the self-sufficiency of fuel cycle for a candidate power blanket concept

Neutron source multiplication method

International Nuclear Information System (INIS)

Clayton, E.D.

1985-01-01

Extensive use has been made of neutron source multiplication in thousands of measurements of critical masses and configurations and in subcritical neutron-multiplication measurements in situ that provide data for criticality prevention and control in nuclear materials operations. There is continuing interest in developing reliable methods for monitoring the reactivity, or k/sub eff/, of plant operations, but the required measurements are difficult to carry out and interpret on the far subcritical configurations usually encountered. The relationship between neutron multiplication and reactivity is briefly discussed and data presented to illustrate problems associated with the absolute measurement of neutron multiplication and reactivity in subcritical systems. A number of curves of inverse multiplication have been selected from a variety of experiments showing variations observed in multiplication during the course of critical and subcritical experiments where different methods of reactivity addition were used, with different neutron source detector position locations. Concern is raised regarding the meaning and interpretation of k/sub eff/ as might be measured in a far subcritical system because of the modal effects and spectrum differences that exist between the subcritical and critical systems. Because of this, the calculation of k/sub eff/ identical with unity for the critical assembly, although necessary, may not be sufficient to assure safety margins in calculations pertaining to far subcritical systems. Further study is needed on the interpretation and meaning of k/sub eff/ in the far subcritical system

Spallation neutron source target station issues

International Nuclear Information System (INIS)

Gabriel, T.A.; Barnes, J.N.; Charlton, L.A.

1996-01-01

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 (∼ 1 MW) proton accelerator, and (2) a target station which converts the protons to low-energy (≤ 2 eV) neutrons and delivers them to the neutron scattering instruments. This paper deals with the second part, i.e., the design and development of the NSNS target station and the scientifically challenging issues. Many scientific and technical disciplines are required to produce a successful target station. These include engineering, remote handling, neutronics, materials, thermal hydraulics, and instrumentation. Some of these areas will be discussed

Plasma-focus neutron diagnostics by means of high-sensitivity bubble detectors

International Nuclear Information System (INIS)

Zoita, V.; Pantea, A.; Patran, A.; Lee, P.; Springham, S.V.; Koh, M.; Rawat, R.S.; Zhang, T.; Hassan, M.

2005-01-01

A new type of bubble detector (a superheated fluid detector), the DEFENDER TM , was tested as a neutron diagnostics device on the NX2 plasma focus (PF) device at the NIE/NTU, Singapore. The DEFENDER TM detector was recently developed and commercialised by BTI, Canada, and it is characterised by a very high sensitivity (a factor of about 30 higher than the standard detectors) to fast neutrons (energy above 100 keV). Together with its particular energy response this high sensitivity allows for the development of improved neutron diagnostics for the PF devices. The NX2 plasma focus device has the following typical operating parameters: condenser bank charging voltage: 15 kV; stored energy: 2.3 kJ; peak current: 420 kA; current rise-time: 1.35 μs; deuterium pressure: 20 mbar. During most of the experiments reported here the NX2 device was operated at 14 kV charging voltage and 20 mbar deuterium pressure. A few shots were done at voltages of 14.5 and 15 kV and the same gas pressure. The bubble detector neutron diagnostics experiments carried out on the NX2 machine involved the following measurements: 1. Relative calibration of the four detectors. The detectors were irradiated simultaneously, in identical conditions, by plasma focus neutron pulses and their neutron responses were compared.; 2. angular distribution of the neutron fluence (single shot). The distribution of the neutron fluence was measured at four angles with respect to the PF electrode axis: 0, 30, 60 and 90 deg; 3. Reproducibility of the neutron yield at high repetition rate operation. The NX2 device was operated at 1 Hz repetition rate.; 4. Bubble detector response time. The response time of the DEFENDER TM detector was tested by using the short PF neutron pulses and a high-speed video camera. The paper will present the results of these experiments and their implications for the development of neutron plasma diagnostics techniques based on the bubble detectors and their broader class of superheated

How should the JAERI neutron source be designed?

International Nuclear Information System (INIS)

Watanabe, Noboru

1996-01-01

The importance of a next-generation neutron source in JAERI is discussed. The feasibility and the performances of three types of neutron sources, namely continuous wave spallation source (CWSS), long-pulse spallation source (LPSS) and short-pulse spallation source (SPSS), are compared based on a proposed JAERI accelerator, a superconducting (SC) proton linac (1-1.5 GeV, 25-16 mA in peak current, finally CW). How to realize one of the world's best neutron source using such a linac with a modest beam-current and what type of neutron source is the best for such a linac are the most important current problems. Since the accelerator is not favorable for LPSS due to a lower peak current and there exist serious technical problems for a CWSS target, a short-pulse spallation source would be the best candidate to realize a 5 MW-class SPSS like ESS, provided that the H - -injection to a compressor ring over a long pulse duration (>2 ms) is feasible. (author)

Characteristics of a High Current Helicon Ion Source With High Monatomic Fraction

International Nuclear Information System (INIS)

Jung, Hwa-Dong; Chung, Kyoung-Jae; Hwang, Yong-Seok

2006-01-01

Applications of neutron need compact and high yield neutron sources as well as very intense neutron sources from giant devices such as accelerators. Ion source based neutron sources using nuclear fusion reactions such as D(d, 3He)n, D(t, 4He)n can meet the requirements. This type of neutron generators can be simply composed of an ion source and a target. High-performance neutron generators with high yield require ion sources with high beam current, high monatomic fraction and long lifetime. Helicon ion source can meet these requirements. To make high current ion source, characteristics of helicon plasma such as high plasma density can be utilized. Moreover, efficient plasma heating with RF power lead high fraction of monatomic ion beam. Here, Characteristics of helicon plasma sources are described. Design and its performances of a helicon ion source are presented

Spallation neutron source moderator design

International Nuclear Information System (INIS)

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

1998-01-01

This paper describes various aspects of the spallation neutron source (SNS) moderator design. Included are the effects of varying the moderator location, interaction effects between moderators, and the impact on neutron output when various reflector materials are used. Also included is a study of the neutron output from composite moderators, where it is found that a combination of liquid H 2 O and liquid H 2 can produce a spectrum very similar to liquid methane (L-CH 4 ). (orig.)

Small accelerator-based pulsed cold neutron sources

International Nuclear Information System (INIS)

Lanza, Richard C.

1997-09-01

Small neutron sources could be used by individual researchers with the convenience of an adequate local facility. Although these sources would produce lower fluxes than the national facilities, for selected applications, the convenience and availability may overcome the limitations on source strength. Such sources might also be useful for preliminary testing of ideas before going to a larger facility. Recent developments in small, high-current pulsed accelerators makes possible such a local source for pulsed cold neutrons.

New sources and instrumentation for neutrons in biology

DEFF Research Database (Denmark)

Teixeira, S. C. M.; Zaccai, G.; Ankner, J.

2008-01-01

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.......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....

Miniature neutron sources: Thermal neutron sources and their users in the academic field

International Nuclear Information System (INIS)

Egelstaff, P.A.

1992-01-01

The three levels of thermal neutron sources are introduced - University laboratory sources infrastructure sources and world-class sources - and the needs for each kind and their inter-dependence will be emphasized. A description of the possibilities for University sources based on α-Be reactions or spontaneous fission emission is given, and current experience with them is described. A new generation of infrastructure sources is needed to continue the regional programs based on small reactors. Some possibilities for accelerator sources that could meet this need are considered

Recovery of spent high intensity neutron sources in Atalante Facility

International Nuclear Information System (INIS)

Bros, P.; Boyer Deslys, V.; Millet, A.; Solinhac, I.; Donnet, L.; Maillard, C.; Paillard, S.; Ranchoux, M.

2005-01-01

The Atalante facility is required by law to recover both neutron and gamma sources with activity levels exceeding 300 mCi. Most of the neutron sources consist of mixtures of alpha-emitters (238Pu, 239Pu, 241Am or 244Cm) and beryllium. Several processes now under consideration are based on routine chemical separation techniques (selective precipitation, extraction chromatography, ion exchange). The treatment produces an actinide oxide (which is used later for R and D studies) and solid beryllium nitrate, which is considered as a waste and transferred to a surface interim storage site if the overall activity of the package after 300 years is less than 50 MBq (ANDRA specifications). The Material Analysis and Metrology Laboratory of Atalante validate the residual alpha activity in the waste. The techniques used include alpha spectrometry and L-line X-ray fluorescence for alpha emitters, and plasma torch measurements (ICP-AES and ICP-MS) for beryllium analysis. Specific equipment for transport (B type cask), storage and treatment (hot shielded cells) are used for this activity. (Author)

Targets for neutron beam spallation sources

International Nuclear Information System (INIS)

Bauer, G.S.

1980-01-01

The meeting on Targets for Neutron Beam Spallation Sources held at the Institut fuer Festkoerperforschung at KFA Juelich on June 11 and 12, 1979 was planned as an informal get-together for scientists involved in the planning, design and future use of spallation neutron sources in Europe. These proceedings contain the papers contributed to this meeting. For further information see hints under relevant topics. (orig./FKS)

Accelerator-driven neutron sources for materials research

International Nuclear Information System (INIS)

Jameson, R.A.

1990-01-01

Particle accelerators are important tools for materials research and production. Advances in high-intensity linear accelerator technology make it possible to consider enhanced neutron sources for fusion material studies or as a source of spallation neutrons. Energy variability, uniformity of target dose distribution, target bombardment from multiple directions, time-scheduled dose patterns, and other features can be provided, opening new experimental opportunities. New designs have also been used to ensure hands-on maintenance on the accelerator in these factory-type facilities. Designs suitable for proposals such as the Japanese Energy-Selective Intense Neutron Source, and the international Fusion Materials Irradiation Facility are discussed

Future neutron data activity on the neutron source IREN

International Nuclear Information System (INIS)

Janeva, N.B.; Koyumdjieva, N.T.; Grigoriev, Y.V.; Gundorin, N.A.; Mareev, Y.D.; Kopatch, Y.N.; Pikelner, L.B.; Shvetsov, V.N.; Sedyshev, P.V.; Zeinalov, S.; Ruskov, I.N.

2011-01-01

The global energy demand continues to rise and nuclear power has a potential to be part of the solution of energy problem. Complete and accurate information about the nuclear reactions ensures developing and operating nuclear reactors to reach high efficiencies and adequate safety standards. This demands many nuclear data of improved quality, including covariance nuclear data and correlations. The new neutron source IREN (1 stage) has been put in operation at the end of 2009. The first stage includes the construction of the LUE-200 linear accelerator and non multiplying target. The first measured TOF spectra have been presented recently. The facility is in continuous completion and improvement (according to the full version in the project). The program for neutron data investigation on the IREN neutron source is in preparation. The measuring targets for neutron cross-sections TOF spectra would be selected between isotopes of construction materials, fission products and minor actinides. Now the experimental facilities are in preparation - detectors, innovative electronics equipment and systems for data acquisition and analysis. (authors)

Procedures for measurement of anisotropy factor of neutron sources

International Nuclear Information System (INIS)

Creazolla, P.G.; Camargo, A.; Astuto, A.; Silva, F.; Pereira, W.W.

2017-01-01

Radioisotope sources of neutrons allow the production of reference fields for calibration of neutron measurement devices for radioprotection and analysis purposes. When the emission rate of these sources is isotropic, no correction is necessary. However, variations in the source capsule material and variations in the concentration of the emitting material may produce differences in its neutron emission rate relative to the source axis, this effect is called anisotropy. A proposed procedure for measuring the anisotropy factor of the sources belonging to the IRD/LNMRI/LN Neutron Metrology Laboratory using a Precision Long Counter (PLC) detector will be presented

Study of neutron focusing at the Texas Cold Neutron Source. Final report

International Nuclear Information System (INIS)

Wehring, B.W.; Uenlue, K.

1995-01-01

Funds were received for the first year of a three year DOE Nuclear Engineering Research Grant, ''Study of Neutron Focusing at the Texas Cold Neutron Source'' (FGO2-92ER75711). The purpose of this three year study was to develop a neutron focusing system to be used with the Texas Cold Neutron Source (TCNS) to produce an intense beam of neutrons. A prompt gamma activation analysis (PGAA) facility was also to be designed, setup, and tested under the three year project. During the first year of the DOE grant, a new procedure was developed and used to design a focusing converging guide consisting of truncated rectangular cone sections. Detailed calculations were performed using a 3-D Monte Carlo code which we wrote to trace neutrons through the curved guide of the TCNS into the proposed converging guide. Using realistic reflectivities for Ni-Ti supermirrors, we obtained gains of 3 to 5 for the neutron flux averaged over an area of 1 x 1 cm

A Broad Coverage Neutron Source For Security Inspections

Science.gov (United States)

Yang, Yang; Robert, Stubbers; Linchun, Wu; George, Miley

2004-05-01

To meet the increasing demanding requirements for security safety inspections, a line-type neutron source employing a cylindrical IEC (RC-IEC) is proposed for non-destructive "in situ" security inspections. The advantages of such a neutron source include line geometry, modularity, swithcability, variable source strength, low cost with minimum maintenance. Detailed description of a 1/3 scale cylindrical device is presented, which might demonstrate that a reasonably long RC-IEC produces a stable discharge with reasonably uniform neutron production along the cylindrical axis. Aiming at the neutron production efficiency at the order of 106 n/J, several methods to maximize neutron production efficiency are discussed. The results of a two-dimensional computer code(MCP) using a Monte Carlo numerical approach for the RC-IEC device are presented together with an analysis of neutron yield vs. different operation parameters.

Neutron time-of-flight counters and spectrometers for diagnostics of burning fusion plasmas

International Nuclear Information System (INIS)

Elevant, T.; Olsson, M.

1991-02-01

Experiment with burning fusion plasmas in tokamaks will place particular requirements on neutron measurements from radiation resistance-, physics-, burn control- and reliability considerations. The possibility to meet these needs by measurements of neutron fluxes and energy spectra by means of time-of-flight techniques are described. Reference counters and spectrometers are proposed and characterized with respect to efficiency, count-rate capabilities, energy resolution and tolerable neutron and γ-radiation background levels. The instruments can be used in a neutron camera and are capable to operate in collimated neutron fluxes up to levels corresponding to full nuclear output power in the next generation of experiments. Energy resolutions of the spectrometers enables determination of ion temperatures from 3 (keV) through analysis of the Doppler broadening. Primarily, the instruments are aimed for studies of 14 (MeV) neutrons produced in (d,t)-plasmas but can, after minor modifications, be used for analysis of 2.45 (MeV) neutrons produced in (d,d)-plasma. (au) (33 refs.)

Spallation Neutron Sources For Science And Technology

International Nuclear Information System (INIS)

Comsan, M.N.H.

2011-01-01

Spallation Neutron Facilities Increasing interest has been noticed in spallation neutron sources (SNS) during the past 20 years. The system includes high current proton accelerator in the GeV region and spallation heavy metal target in the Hg-Bi region. Among high flux currently operating SNSs are: ISIS in UK (1985), SINQ in Switzerland (1996), JSNS in Japan (2008), and SNS in USA (2010). Under construction is the European spallation source (ESS) in Sweden (to be operational in 2020). The intense neutron beams provided by SNSs have the advantage of being of non-reactor origin, are of continuous (SINQ) or pulsed nature. Combined with state-of-the-art neutron instrumentation, they have a diverse potential for both scientific research and diverse applications. Why Neutrons? Neutrons have wavelengths comparable to interatomic spacings (1-5 A) Neutrons have energies comparable to structural and magnetic excitations (1-100 meV) Neutrons are deeply penetrating (bulk samples can be studied) Neutrons are scattered with a strength that varies from element to element (and isotope to isotope) Neutrons have a magnetic moment (study of magnetic materials) Neutrons interact only weakly with matter (theory is easy) Neutron scattering is therefore an ideal probe of magnetic and atomic structures and excitations Neutron Producing Reactions Several nuclear reactions are capable of producing neutrons. However the use of protons minimises the energetic cost of the neutrons produced solid state physics and astrophysics Inelastic neutron scattering

Accelerating fissile material detection with a neutron source

Science.gov (United States)

Rowland, Mark S.; Snyderman, Neal J.

2018-01-30

A neutron detector system for discriminating fissile material from non-fissile material wherein a digital data acquisition unit collects data at high rate, and in real-time processes large volumes of data directly to count neutrons from the unknown source and detecting excess grouped neutrons to identify fission in the unknown source. The system includes a Poisson neutron generator for in-beam interrogation of a possible fissile neutron source and a DC power supply that exhibits electrical ripple on the order of less than one part per million. Certain voltage multiplier circuits, such as Cockroft-Walton voltage multipliers, are used to enhance the effective of series resistor-inductor circuits components to reduce the ripple associated with traditional AC rectified, high voltage DC power supplies.

Basic physical phenomena, neutron production and scaling of the dense plasma focus

International Nuclear Information System (INIS)

Kaeppeler, H.J.

This paper presents an attempt at establishing a model theory for the dense plasma focus in order to present a consistent interpretation of the basic physical phenomena leading to neutron production from both acceleration and thermal processes. To achieve this, the temporal history of the focus is divided into the compression of the plasma sheath, a qiescent and very dense phase with ensuing expansion, and an instable phase where the focus plasma is disrupted by instabilities. Finally, the decay of density, velocity and thermal fields is considered. Under the assumption that Io 2 /sigmaoRo 2 = const and to/Tc = const, scaling laws for plasma focus devices are derived. It is shown that while generally the neutron yield scales with the fourth power of maximum current, neutron production from thermal processes becomes increasingly important for large devices, while in the small devices neutron production from acceleration processes is by far predominant. (orig.) [de

Analysis of the neutron generation from a D-Li neutron source

International Nuclear Information System (INIS)

Gomes, I.

1994-02-01

The study of the neutron generation from the D-Li reaction is an important issue to define the optimum combination of the intervening parameters during the design phase of a D-Li neutron source irradiation facility. The major players in defining the neutron yield from the D-Li reaction are the deuteron incident energy and the beam current, provided that the lithium target is thick enough to stop all incident deuterons. The incident deuteron energy also plays a role on the angular distribution of the generated neutrons, on the energy distribution of the generated neutrons, and on the maximum possible energy of the neutrons. The D-Li reaction produces neutrons with energies ranging from eV's to several MeV's. The angular distribution of these neutrons is dependent on the energy of both, incident deuterons and generated neutrons. The deuterons lose energy interacting with the lithium target material in such a way that the energy of the deuterons inside the lithium target varies from the incident deuteron energy to essentially zero. The first part of this study focuses in analyzing the neutron generation rate from the D-Li reaction as a function of the intervening parameters, in defining the source term, in terms of the energy and angular distributions of the generated neutrons, and finally in providing some insights of the impact of varying input parameters on the generation rate and correlated distributions. In the second part an analytical description of the Monte Carlo sampling procedure of the neutron from the D-Li reaction is provided with the aim at further Monte Carlo transport of the D-Li neutrons

Future opportunities with pulsed neutron sources

Energy Technology Data Exchange (ETDEWEB)

Taylor, A D [Rutherford Appleton Lab., Chilton (United Kingdom)

1996-05-01

ISIS is the world`s most powerful pulsed spallation source and in the past ten years has demonstrated the scientific potential of accelerator-driven pulsed neutron sources in fields as diverse as physics, earth sciences, chemistry, materials science, engineering and biology. The Japan Hadron Project gives the opportunity to build on this development and to further realize the potential of neutrons as a microscopic probe of the condensed state. (author)

Advanced spallation neutron sources for condensed matter research

International Nuclear Information System (INIS)

Lovesey, S.W.; Stirling, G.C.

1984-03-01

Advanced spallation neutron sources afford significant advantages over existing high flux reactors. The effective flux is much greater than that currently available with reactor sources. A ten-fold increase in neutron flux will be a major benefit to a wide range of condensed matter studies, and it will realise important experiments that are marginal at reactor sources. Moreover, the high intensity of epithermal neutrons open new vistas in studies of electronic states and molecular vibrations. (author)

Development of resonant detectors for epithermal neutron spectroscopy at pulsed neutron sources

International Nuclear Information System (INIS)

Tardocchi, M.; Pietropaolo, A.; Senesi, R.; Andreani, C.; Gorini, G.

2004-01-01

New perspectives for epithermal neutron spectroscopy are opened by the development of new detectors for inverse geometry time of flight spectrometers at pulsed neutron sources. One example is the Very Low Angle Detector (VLAD) bank planned to be delivered, within the next 4 years, within the eVERDI project, on the neutron spectrometer VESUVIO, at the ISIS pulsed neutron source (UK). VLAD will extend the (q,ω) kinematical region for neutron scattering to low wavefactor transfer (q -1 ) still keeping energy transfer >1 eV, thus allowing the investigations of new experimental studies in condensed matter systems. The technique being developed for detection of epithermal neutrons, within this low q and high-energy transfer region, is the Resonance Detection Technique. In this work, the state of the detector development will be presented with special focus on the results obtained with some prototype detectors, namely YAP scintillators and cadmium-zinc-telluride semiconductors

A collimated neutron detector for RFP plasmas in MST

Energy Technology Data Exchange (ETDEWEB)

Capecchi, W. J., E-mail: capecchi@wisc.edu; Anderson, J. K.; Bonofiglo, P. J.; Kim, J.; Sears, S. [University of Wisconsin- Madison, Madison, Wisconsin 53706 (United States)

2016-11-15

The neutron emissivity profile in the Madison Symmetric Torus is being reconstructed through the use of a collimated neutron detector. A scintillator-photomultiplier tube (PMT) system is employed to detect the fusion neutrons with the plasma viewing volume defined by a 55 cm deep, 5 cm diameter aperture. Effective detection of neutrons from the viewing volume is achieved through neutron moderation using 1300 lbs of high density polyethylene shielding, which modeling predicts attenuates the penetrating flux by a factor of 10{sup 4} or more. A broad spectrum of gamma radiation is also present due to the unconfined fusion proton bombardment of the thick aluminum vacuum vessel. A 15 cm cylindrical liquid scintillator of 3.8 cm diameter is used to further increase directional sensitivity. A fast (5 ns rise time) preamplifier and digitization at 500 MHz prevent pulse pile-up even at high count rates (∼10{sup 4}/s). The entire neutron camera system is situated on an adjustable inclining base which provides the differing plasma viewing volumes necessary for reconstruction of the neutron emissivity profile. This profile, directly related to the fast-ion population, allows for an investigation of the critical fast-ion pressure gradient required to destabilize a neutral beam driven Alfvénic mode which has been shown to transport fast ions.

Reactor cold neutron source facility, the first in Japan

International Nuclear Information System (INIS)

Utsuro, Masahiko; Maeda, Yutaka; Kawai, Takeshi; Tashiro, Tameyoshi; Sakakibara, Shoji; Katada, Minoru.

1986-01-01

In the Research Reactor Institute, Kyoto University, the first cold neutron source facility for the reactor in Japan was installed, and various tests are carried out outside the reactor. Nippon Sanso K.K. had manufactured it. After the prescribed tests outside the reactor, this facility will be installed soon in the reactor, and its outline is described on this occasion. Cold neutrons are those having very small energy by being cooled to about-250 deg C. Since the wavelength of the material waves of cold neutrons is long, and their energy is small, they are very advantageous as an experimental means for clarifying the structure of living body molecules and polymers, the atom configuration in alloys, and atomic and molecular movements by neutron scattering and neutron diffraction. The basic principle of the cold neutron source facility is to irradiate thermal neutrons on a cold moderator kept around 20 K, and to moderate and cool the neutrons by nuclear scattering to convert to cold neutrons. The preparatory research on cold neutrons and hydrogen liquefaction, the basic design to put the cold neutron source facility in the graphite moderator facility, the safety countermeasures, the manufacture and quality control, the operation outside the reactor and the performance are reported. The cold neutron source facility comprises a cold moderator tank and other main parts, a deuterium gas tank, a helium refrigerator and instrumentation. (Kako, I.)

Investigation of the neutron production phases of a large plasma focus device

International Nuclear Information System (INIS)

Hayd, A.; Maurer, M.; Meinke, P.; Herold, H.; Bertalot, L.; Deutsch, R.; Grauf, W.; Jaeger, U.; Kaeppeler, H.J.; Lepper, F.; Oppenlaender, T.; Schmidt, H.; Schmidt, R.; Schwarz, J.; Schwoerer, K.; Shakhatre, M.

1982-09-01

Plasma dynamic behavior and neutron production in large focus devices with pinch currents of approximately 1 MA have been studied with theoretical as well as experimental methods. For treating turbulent plasma motion, a hybrid code based on the analytical computer algorithm REDUCE was developed. Experimental diagnostics include schlieren photographs, reaction proton localization with pinhole cameras and neutron measurements with Ag-counters and scintillators. Calculated and measured data concern the 280 kJ, 60 kV operational mode of the POSEIDON plasma focus. It is shown that for large pinch currents ( > 500 kA), neutron emission also appears before m = 0 onset in the intermediate phase. This part of the neutron production becomes predominant for very large currents. The lifetime of this intermediate phase strongly increases with increasing current. According to theory, the late phase of the focus is governed by strong turbulence phenomena. The lifetime of the turbulence packets is approximately 150 ns and seems to explain the long lasting neutron emission in this phase. (orig.)

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

International Nuclear Information System (INIS)

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

1999-01-01

The radioisotope 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 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 252 Cf to commercial reencapsulators domestically and internationally. Sealed 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 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

Neutron-irradiation facilities at the Intense Pulsed Neutron Source-I for fusion magnet materials studies

International Nuclear Information System (INIS)

Brown, B.S.; Blewitt, T.H.

1982-01-01

The decommissioning of reactor-based neutron sources in the USA has led to the development of a new generation of neutron sources that employ high-energy accelerators. Among the accelerator-based neutron sources presently in operation, the highest-flux source is the Intense Pulsed Neutron Source (IPNS), a user facility at Argonne National Laboratory. Neutrons in this source are produced by the interaction of 400 to 500 MeV protons with either of two 238 U target systems. In the Radiation Effects Facility (REF), the 238 U target is surrounded by Pb for neutron generatjion and reflection. The REF has three separate irradiation thimbles. Two thimbles provide irradiation temperatures between that of liquid He and several hundred degrees centigrade. The third thimble operates at ambient temperature. The large irradiation volume, the neutron spectrum and flux, the ability to transfer samples without warm up, and the dedication of the facilities during the irradiation make this ideally suited for radiation damage studies on components for superconducting fusion magnets. Possible experiments for fusion magnet materials are discussed on cyclic irradiation and annealing of stabilizers in a high magnetic field, mechanical tests on organic insulation irradiated at 4 K, and superconductors measured in high fields after irradiation

Observation of Neutron Skyshine from an Accelerator Based Neutron Source

Energy Technology Data Exchange (ETDEWEB)

Franklyn, C. B. [Radiation Science Department, Necsa, PO Box 582, Pretoria 0001 (South Africa)

2011-12-13

A key feature of neutron based interrogation systems is the need for adequate provision of shielding around the facility. Accelerator facilities adapted for fast neutron generation are not necessarily suitably equipped to ensure complete containment of the vast quantity of neutrons generated, typically >10{sup 11} n{center_dot}s{sup -1}. Simulating the neutron leakage from a facility is not a simple exercise since the energy and directional distribution can only be approximated. Although adequate horizontal, planar shielding provision is made for a neutron generator facility, it is sometimes the case that vertical shielding is minimized, due to structural and economic constraints. It is further justified by assuming the atmosphere above a facility functions as an adequate radiation shield. It has become apparent that multiple neutron scattering within the atmosphere can result in a measurable dose of neutrons reaching ground level some distance from a facility, an effect commonly known as skyshine. This paper describes a neutron detection system developed to monitor neutrons detected several hundred metres from a neutron source due to the effect of skyshine.

In-situ calibration of TFTR [Tokamak Fusion Test Reactor] neutron detectors

International Nuclear Information System (INIS)

Hendel, H.W.; Palladino, R.W.; Barnes, C.W.; Diesso, M.; Felt, J.S.; Jassby, D.L.; Johnson, L.C.; Ku, L.P.; Liu, Q.P.; Motley, R.W.; Murphy, H.B.; Murphy, J.; Nieschmidt, E.B.; Roberts, J.A.; Saito, T.; Strachan, J.D.; Waszazak, R.J.; Young, K.

1990-03-01

We report results of the TFTR fission detector calibration performed in December 1988. A NBS-traceable, remotely controlled 252 Cf neutron source was moved toroidally through the TFTR vacuum vessel. Detection efficiencies for two 235 U detectors were measured for 930 locations of the neutron point source in toroidal scans at 16 different major radii and vertical heights. These scans effectively simulated the volume-distributed plasma neutron source, and the volume-integrated detection efficiency was found to be insensitive to plasma position. The Campbell mode is useful due to its large overlap with the count rate mode and large dynamic range. The resulting absolute plasma neutron source calibration has an uncertainty of ± 13%. 21 refs., 23 figs., 4 tabs

HFIR cold neutron source moderator vessel design analysis

International Nuclear Information System (INIS)

Chang, S.J.

1998-04-01

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

Status of the advanced neutron source

International Nuclear Information System (INIS)

Hayter, J.B.

1991-01-01

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 U.S. scientific and technological future. The last U.S. 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 U.S. 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 (> 7.5x10 19 m -2 ·s -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. (author)

Standard Practice for Conducting Irradiations at Accelerator-Based Neutron Sources

CERN Document Server

American Society for Testing and Materials. Philadelphia

1996-01-01

1.1 This practice covers procedures for irradiations at accelerator-based neutron sources. The discussion focuses on two types of sources, namely nearly monoenergetic 14-MeV neutrons from the deuterium-tritium T(d,n) interaction, and broad spectrum neutrons from stopping deuterium beams in thick beryllium or lithium targets. However, most of the recommendations also apply to other types of accelerator-based sources, including spallation neutron sources (1). Interest in spallation sources has increased recently due to their proposed use for transmutation of fission reactor waste (2). 1.2 Many of the experiments conducted using such neutron sources are intended to simulate irradiation in another neutron spectrum, for example, that from a DT fusion reaction. The word simulation is used here in a broad sense to imply an approximation of the relevant neutron irradiation environment. The degree of conformity can range from poor to nearly exact. In general, the intent of these simulations is to establish the fundam...

Design and Demonstration of a Material-Plasma Exposure Target Station for Neutron Irradiated Samples

International Nuclear Information System (INIS)

Rapp, Juergen; Aaron, A. M.; Bell, Gary L.; Burgess, Thomas W.; Ellis, Ronald James; Giuliano, D.; Howard, R.; Kiggans, James O.; Lessard, Timothy L.; Ohriner, Evan Keith; Perkins, Dale E.; Varma, Venugopal Koikal

2015-01-01

Fusion energy is the most promising energy source for the future, and one of the most important problems to be solved progressing to a commercial fusion reactor is the identification of plasma-facing materials compatible with the extreme conditions in the fusion reactor environment. The development of plasma-material interaction (PMI) science and the technology of plasma-facing components are key elements in the development of the next step fusion device in the United States, the so-called Fusion Nuclear Science Facility (FNSF). All of these PMI issues and the uncertain impact of the 14-MeV neutron irradiation have been identified in numerous expert panel reports to the fusion community. The 2007 Greenwald report classifies reactor plasma-facing materials (PFCs) and materials as the only Tier 1 issues, requiring a ''. . . major extrapolation from the current state of knowledge, need for qualitative improvements and substantial development for both the short and long term.'' The Greenwald report goes on to list 19 gaps in understanding and performance related to the plasma-material interface for the technology facilities needed for DEMO-oriented R&D and DEMO itself. Of the 15 major gaps, six (G7, G9, G10, G12, G13) can possibly be addressed with ORNL's proposal of an advanced Material Plasma Exposure eXperiment. Establishing this mid-scale plasma materials test facility at ORNL is a key element in ORNL's strategy to secure a leadership role for decades of fusion R&D. That is to say, our end goal is to bring the ''signature facility'' FNSF home to ORNL. This project is related to the pre-conceptual design of an innovative target station for a future Material-Plasma Exposure eXperiment (MPEX). The target station will be designed to expose candidate fusion reactor plasma-facing materials and components (PFMs and PFCs) to conditions anticipated in fusion reactors, where PFCs will be exposed to dense high-temperature hydrogen plasmas providing steady-state heat fluxes of

Advanced Neutron Source (ANS) Project progress report

International Nuclear Information System (INIS)

McBee, M.R.; Chance, C.M.

1990-04-01

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 ampersand C research and development; facility concepts; design; and safety

Neutron activation analysis: Modelling studies to improve the neutron flux of Americium–Beryllium source

Directory of Open Access Journals (Sweden)

Abdessamad Didi

2017-06-01

Full Text Available Americium–beryllium (Am-Be; n, γ is a neutron emitting source used in various research fields such as chemistry, physics, geology, archaeology, medicine, and environmental monitoring, as well as in the forensic sciences. It is a mobile source of neutron activity (20 Ci, yielding a small thermal neutron flux that is water moderated. The aim of this study is to develop a model to increase the neutron thermal flux of a source such as Am-Be. This study achieved multiple advantageous results: primarily, it will help us perform neutron activation analysis. Next, it will give us the opportunity to produce radio-elements with short half-lives. Am-Be single and multisource (5 sources experiments were performed within an irradiation facility with a paraffin moderator. The resulting models mainly increase the thermal neutron flux compared to the traditional method with water moderator.

Design of a portable directional neutron source finder

International Nuclear Information System (INIS)

Yamanishi, Hirokuni

2005-01-01

An instrument that determines the direction of a remote existing neutron source has been designed. This instrument combines a polyethylene block and four 3 He counter tubes. The advantages of the instrument are portability and good angular resolution. The count from the detector was varied with the neutron incident angle due to the moderator. Using this characteristic, the direction of the neutron source can be measured precisely by revising the axis of the instrument so that the difference between the four detectors measurements is minimized. Consequently, the direction of the central axis of the instrument in which the response difference of the four detectors reaches a minimum indicates the direction of the neutron source. The practical use of the instrument was demonstrated by 252 Cf source irradiation experiment and MCNP simulation

The University of Texas Cold Neutron Source

International Nuclear Information System (INIS)

Uenlue, Kenan; Rios-Martinez, Carlos; Wehring, B.W.

1994-01-01

A cold neutron source has been designed, constructed, and tested by the Nuclear Engineering Teaching Laboratory (NETL) at The University of Texas at Austin. The Texas Cold Neutron Source (TCNS) is located in one of the beam ports of the NETL 1-MW TRIGA Mark II research reactor. The main components of the TCNS are a cooled moderator, a heat pipe, a cryogenic refrigerator, and a neutron guide. 80 ml of mesitylene moderator are maintained at about 30 K in a chamber within the reactor graphite reflector by the heat pipe and cryogenic refrigerator. The heat pipe is a 3-m long aluminum tube that contains neon as the working fluid. The cold neutrons obtained from the moderator are transported by a curved 6-m long neutron guide. This neutron guide has a radius of curvature of 300 m, a 50x15 mm cross-section, 58 Ni coating, and is separated into three channels. The TCNS will provide a low-background subthermal neutron beam for neutron capture and scattering research. After the installation of the external portion of the neutron guide, a neutron focusing system and a Prompt Gamma Activation Analysis facility will be set up at the TCNS. ((orig.))

New spallation neutron sources, their performance and applications

International Nuclear Information System (INIS)

1985-01-01

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 14 n cm -2 s -1 at a repetition rate of 30 Hz, and globally producing approx. 1.5 x 10 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 μA). 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. Such machines will be expensive and require national, if not international, collaboration across a wide spectrum of scientific disciplines. The new opportunities for neutron research will, of course, be dramatic with these new sources

Measurement of radiation skyshine with D-T neutron source

Energy Technology Data Exchange (ETDEWEB)

Yoshida, S.; Nishitani, T. E-mail: nisitani@naka.jaeri.go.jp; Ochiai, K.; Kaneko, J.; Hori, J.; Sato, S.; Yamauchi, M.; Tanaka, R.; Nakao, M.; Wada, M.; Wakisaka, M.; Murata, I.; Kutsukake, C.; Tanaka, S.; Sawamura, T.; Takahashi, A

2003-09-01

The D-T neutron skyshine experiments have been carried out at the Fusion Neutronics Source (FNS) of JAERI with the neutron yield of {approx}1.7x10{sup 11} n/s. The concrete thickness of the roof and the wall of a FNS target room are 1.15 and 2 m, respectively. The FNS skyshine port with a size of 0.9x0.9 m{sup 2} was open during the experimental period. The radiation dose rate outside the target room was measured a maximum distance of 550 m from the D-T target point with a spherical rem-counter. Secondary gamma-rays were measured with high purity Ge detectors and NaI scintillation counters. The highest neutron dose was about 9x10{sup -22} Sv/(source neutron) at a distance of 30 m from the D-T target point and the dose rate was attenuated to 4x10{sup -24} Sv/(source neutron) at a distance of 550 m. The measured neutron dose distribution was analyzed with Monte Carlo code MCNP-4B and a simple line source model. The MCNP calculation overestimates the neutron dose in the distance range larger than 230 m. The line source model agrees well with the experimental results within the distance of 350 m.

Adaptation of metal arc plasma source to plasma source ion implantation

International Nuclear Information System (INIS)

Shamim, M.M.; Fetherston, R.P.; Conrad, J.R.

1995-01-01

In Plasma Source Ion Implantation (PSII) a target is immersed in a plasma and a train of high negative voltage pulses is applied to accelerate ions into the target and to modify the properties in the near surface region. In PSII, until now the authors have been using gaseous species to generate plasmas. However metal ion plasma may be used to modify the surface properties of material for industrial applications. Conventionally the ion implantation of metal ions is performed using beam line accelerators which have complex engineering and high cost. The employment of a metal arc source to PSII has tremendous potential due to its ability to process the conformal surfaces, simple engineering and cost effectiveness. They have installed metal arc source for generation of titanium plasma. Currently, they are investigating the properties of titanium plasma and material behavior of titanium implanted aluminum and 52100 steel. The recent results of this investigation are presented

Modeling a neutron rich nuclei source

Energy Technology Data Exchange (ETDEWEB)

Mirea, M.; Bajeat, O.; Clapier, F.; Ibrahim, F.; Mueller, A.C.; Pauwels, N.; Proust, J. [Institut de Physique Nucleaire, IN2P3/CNRS, 91 - Orsay (France); Mirea, M. [Institute of Physics and Nuclear Engineering, Tandem Lab., Bucharest (Romania)

2000-07-01

The deuteron break-up process in a suitable converter gives rise to intense neutron beams. A source of neutron rich nuclei based on the neutron induced fission can be realised using these beams. A theoretical optimization of such a facility as a function of the incident deuteron energy is reported. The model used to determine the fission products takes into account the excitation energy of the target nucleus and the evaporation of prompt neutrons. Results are presented in connection with a converter-target specific geometry. (author000.

Modeling a neutron rich nuclei source

International Nuclear Information System (INIS)

Mirea, M.; Bajeat, O.; Clapier, F.; Ibrahim, F.; Mueller, A.C.; Pauwels, N.; Proust, J.; Mirea, M.

2000-01-01

The deuteron break-up process in a suitable converter gives rise to intense neutron beams. A source of neutron rich nuclei based on the neutron induced fission can be realised using these beams. A theoretical optimization of such a facility as a function of the incident deuteron energy is reported. The model used to determine the fission products takes into account the excitation energy of the target nucleus and the evaporation of prompt neutrons. Results are presented in connection with a converter-target specific geometry. (authors)

Neutron spectra of /sup 239/Pu-Be neutron sources

Energy Technology Data Exchange (ETDEWEB)

Kumar, A; Nagarajan, P S [Bhabha Atomic Research Centre, Bombay (India). Div. of Radiation Protection

1977-01-01

Neutron spectra of /sup 239/Pu-Be(..cap alpha..,n) sources have been calculated by using the most recent data on the differential cross sections and angular distributions. The contribution from the multibody break-up reaction /sup 9/Be(..cap alpha..,..cap alpha..n)/sup 8/Be has also been incorporated. Modifications to the primary spectrum due to the secondary interactions in the source such as elastic scattering with beryllium, oxygen and plutonium and the /sup 9/Be(n,2n) and /sup 239/Pu(n,f) reaction have been calculated for different strengths and geometries. The present calculation has shown that the spectrum changes considerably because of these events within the source by way of smearing of peaks and filling up of valleys and raising the low energy part of the spectrum. Increase in H/D value leads to channeling of extra neutrons into the equatorial plane at the cost of the neutrons along the axial direction. The present calculations show that inclusion of secondary interactions to the extent considered in this work does not account completely for the increased intensity in the lower energy end of the measured spectrum.

Neutronic moderator design for the Spallation Neutron Source (SNS)

International Nuclear Information System (INIS)

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

1998-01-01

Neutronics analyses are now in progress to support the initial selection of moderator design parameters for the Spallation Neutron Source (SNS). The results of the initial optimization studies involving moderator poison plate location, moderator position, and premoderator performance for the target system are presented in this paper. Also presented is an initial study of the use of a composite moderator to produce a liquid methane like spectrum

Neutron activation analysis detection limits using 252Cf sources

International Nuclear Information System (INIS)

DiPrete, D.P.; Sigg, R.A.

2000-01-01

The Savannah River Technology Center (SRTC) developed a neutron activation analysis (NAA) facility several decades ago using low-flux 252 Cf neutron sources. Through this time, the facility has addressed areas of applied interest in managing the Savannah River Site (SRS). Some applications are unique because of the site's operating history and its chemical-processing facilities. Because sensitivity needs for many applications are not severe, they can be accomplished using an ∼6-mg 252 Cf NAA facility. The SRTC 252 Cf facility continues to support applied research programs at SRTC as well as other SRS programs for environmental and waste management customers. Samples analyzed by NAA include organic compounds, metal alloys, sediments, site process solutions, and many other materials. Numerous radiochemical analyses also rely on the facility for production of short-lived tracers, yielding by activation of carriers and small-scale isotope production for separation methods testing. These applications are more fully reviewed in Ref. 1. Although the flux [approximately2 x 10 7 n/cm 2 ·s] is low relative to reactor facilities, more than 40 elements can be detected at low and sub-part-per-million levels. Detection limits provided by the facility are adequate for many analytical projects. Other multielement analysis methods, particularly inductively coupled plasma atomic emission and inductively coupled plasma mass spectrometry, can now provide sensitivities on dissolved samples that are often better than those available by NAA using low-flux isotopic sources. Because NAA allows analysis of bulk samples, (a) it is a more cost-effective choice when its sensitivity is adequate than methods that require digestion and (b) it eliminates uncertainties that can be introduced by digestion processes

Studies and modeling of cold neutron sources; Etude et modelisation des sources froides de neutron

Energy Technology Data Exchange (ETDEWEB)

Campioni, G

2004-11-15

With the purpose of updating knowledge in the fields of cold neutron sources, the work of this thesis has been run according to the 3 following axes. First, the gathering of specific information forming the materials of this work. This set of knowledge covers the following fields: cold neutron, cross-sections for the different cold moderators, flux slowing down, different measurements of the cold flux and finally, issues in the thermal analysis of the problem. Secondly, the study and development of suitable computation tools. After an analysis of the problem, several tools have been planed, implemented and tested in the 3-dimensional radiation transport code Tripoli-4. In particular, a module of uncoupling, integrated in the official version of Tripoli-4, can perform Monte-Carlo parametric studies with a spare factor of Cpu time fetching 50 times. A module of coupling, simulating neutron guides, has also been developed and implemented in the Monte-Carlo code McStas. Thirdly, achieving a complete study for the validation of the installed calculation chain. These studies focus on 3 cold sources currently functioning: SP1 from Orphee reactor and 2 other sources (SFH and SFV) from the HFR at the Laue Langevin Institute. These studies give examples of problems and methods for the design of future cold sources.

Preliminary design of GDT-based 14 MeV neutron source

International Nuclear Information System (INIS)

Du Hongfei; Chen Dehong; Wang Hui; Wang Fuqiong; Jiang Jieqiong; Wu Yican; Chen Yiping

2012-01-01

To meet the need of D-T fusion neutron source for fusion material testing, design goals were presented in this paper according to the international requirements of neutron source for fusion material testing. A preliminary design scheme of GDT-based 14 MeV neutron source was proposed, and a physics model of the neutron source was built based on progress of GDT experiments. Two preliminary design schemes (i. e. FDS-GDT1, FDS-GDT2) were designed; among which FDS-GDT2 can be used for fusion material testing with neutron first wall loading of 2 MW/m 2 . (authors)

Status of the FRM-II hot neutron source

International Nuclear Information System (INIS)

Mueller, C.; Gutsmiedl, E.

2001-01-01

The new research reactor FRM-II will be equipped with a hot neutron source. This secondary source will shift a part of the thermal neutron energy spectrum in the D 2 O moderator to energies from 0.1 to 1 eV. The hot neutron source consists of a graphite cylinder (200 mm diameter, 300 mm high), which is heated by gamma radiation up to a maximum temperature of about 2400 C. The graphite cylinder is surrounded by a high-temperature insulation of carbon fiber, to achieve this high temperature. We have accomplished mock-up tests of the carbon fiber in a high temperature furnace, to investigate the insulation properties of the material. The graphite cylinder and the insulation are covered with two vessels made out of Zircaloy 4. The space between the vessels is filled with helium. The hot neutron source is permanent under control by pressure and temperature measurements. The temperature inside the graphite cylinder will be measured by a purpose-built noise thermometer due to the extremely harsh environment conditions (temperature and nuclear radiation). The hot neutron source is designed and manufactured according to the general specification basic safety and to the German nuclear atomic rules (KTA). The source will be installed in year 2001. (orig.)

Prospect for application of compact accelerator-based neutron source to neutron engineering diffraction

Energy Technology Data Exchange (ETDEWEB)

Ikeda, Yoshimasa, E-mail: yoshimasa.ikeda@riken.jp [Center for Advanced Photonics, RIKEN, Wako, Saitama 351-0198 (Japan); Taketani, Atsushi; Takamura, Masato; Sunaga, Hideyuki [Center for Advanced Photonics, RIKEN, Wako, Saitama 351-0198 (Japan); Kumagai, Masayoshi [Faculty of Engineering, Tokyo City University, Setagaya, Tokyo 158-8857 (Japan); Oba, Yojiro [Research Reactor Institute, Kyoto University, Kumatori, Osaka 590-0494 (Japan); Otake, Yoshie [Center for Advanced Photonics, RIKEN, Wako, Saitama 351-0198 (Japan); Suzuki, Hiroshi [Materials Sciences Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)

2016-10-11

A compact accelerator-based neutron source has been lately discussed on engineering applications such as transmission imaging and small angle scattering as well as reflectometry. However, nobody considers using it for neutron diffraction experiment because of its low neutron flux. In this study, therefore, the neutron diffraction experiments are carried out using Riken Accelerator-driven Compact Neutron Source (RANS), to clarify the capability of the compact neutron source for neutron engineering diffraction. The diffraction pattern from a ferritic steel was successfully measured by suitable arrangement of the optical system to reduce the background noise, and it was confirmed that the recognizable diffraction pattern can be measured by a large sampling volume with 10 mm in cubic for an acceptable measurement time, i.e. 10 min. The minimum resolution of the 110 reflection for RANS is approximately 2.5% at 8 μs of the proton pulse width, which is insufficient to perform the strain measurement by neutron diffraction. The moderation time width at the wavelength corresponding to the 110 reflection is estimated to be approximately 30 μs, which is the most dominant factor to determine the resolution. Therefore, refinements of the moderator system to decrease the moderation time by decreasing a thickness of the moderator or by applying the decoupler system or application of the angular dispersive neutron diffraction technique are important to improve the resolution of the diffraction experiment using the compact neutron source. In contrast, the texture evolution due to plastic deformation was successfully observed by measuring a change in the diffraction peak intensity by RANS. Furthermore, the volume fraction of the austenitic phase in the dual phase mock specimen was also successfully evaluated by fitting the diffraction pattern using a Rietveld code. Consequently, RANS has been proved to be capable for neutron engineering diffraction aiming for the easy access

D-D neutron generator development at LBNL.

Science.gov (United States)

Reijonen, J; Gicquel, F; Hahto, S K; King, M; Lou, T-P; Leung, K-N

2005-01-01

The plasma and ion source technology group in Lawrence Berkeley National Laboratory is developing advanced, next generation D-D neutron generators. There are three distinctive developments, which are discussed in this presentation, namely, multi-stage, accelerator-based axial neutron generator, high-output co-axial neutron generator and point source neutron generator. These generators employ RF-induction discharge to produce deuterium ions. The distinctive feature of RF-discharge is its capability to generate high atomic hydrogen species, high current densities and stable and long-life operation. The axial neutron generator is designed for applications that require fast pulsing together with medium to high D-D neutron output. The co-axial neutron generator is aimed for high neutron output with cw or pulsed operation, using either the D-D or D-T fusion reaction. The point source neutron generator is a new concept, utilizing a toroidal-shaped plasma generator. The beam is extracted from multiple apertures and focus to the target tube, which is located at the middle of the generator. This will generate a point source of D-D, T-T or D-T neutrons with high output flux. The latest development together with measured data will be discussed in this article.

Irradiation facilities at the advanced neutron source

International Nuclear Information System (INIS)

West, C.D.

1992-01-01

The Advanced Neutron Source (ANS) is a facility, centered around a new 330MW(f) heavy-water cooled and reflected research reactor, proposed for construction at Oak Ridge. The main scientific justification for the new source is the United States' need for increased capabilities in neutron scattering and other neutron beam research, but the technical objectives of the project also cater for the need to replace the irradiation facilities at the aging High Flux Isotope Reactor and to provide other research capabilities to the scientific community. This document provides a description of the ANS facilities

Simulated and measured neutron/gamma light output distribution for poly-energetic neutron/gamma sources

Science.gov (United States)

Hosseini, S. A.; Zangian, M.; Aghabozorgi, S.

2018-03-01

In the present paper, the light output distribution due to poly-energetic neutron/gamma (neutron or gamma) source was calculated using the developed MCNPX-ESUT-PE (MCNPX-Energy engineering of Sharif University of Technology-Poly Energetic version) computational code. The simulation of light output distribution includes the modeling of the particle transport, the calculation of scintillation photons induced by charged particles, simulation of the scintillation photon transport and considering the light resolution obtained from the experiment. The developed computational code is able to simulate the light output distribution due to any neutron/gamma source. In the experimental step of the present study, the neutron-gamma discrimination based on the light output distribution was performed using the zero crossing method. As a case study, 241Am-9Be source was considered and the simulated and measured neutron/gamma light output distributions were compared. There is an acceptable agreement between the discriminated neutron/gamma light output distributions obtained from the simulation and experiment.

Commissioning of the Opal reactor cold neutron source

International Nuclear Information System (INIS)

Thiering, R.; Lu, W.; Ullah, R.

2006-01-01

Full text: At OPAL, Australia's first cold neutron facility will form an essential part of the reactor's research programs. Fast neutrons, born in the core of a reactor, interact with a cryogenic material, in this case liquid deuterium, to give them very low energies ( 1 0 m eV). A cold neutron flux of 1.4 1 0 E 1 4 n /cm 2/ s is expected, with a peak in the energy spectrum at 4.2m eV. The cold neutron source reached cryogenic conditions for the first time in late 2005. The cold neutron source operates with a sub-cooled liquid Deuterium moderator at 24 K. The moderator chamber, which contains the deuterium, has been constructed from AlMg 5. The thermosiphon and moderator chamber are cooled by helium gas, in a natural convection thermosiphon loop. The helium refrigeration system utilises the Brayton cycle, and is fully insulated within a high vacuum environment. Despite the proximity of the cold neutron source to the reactor core, it has been considered as effectively separate to the reactor system, due to the design of its special vacuum containment vessel. As OPAL is a multipurpose research reactor, used for beam research as well as radiopharmaceutical production and industrial irradiations, the cold neutron source has been designed with a stand-by mode, to maximise production. The stand-by mode is a warm operating mode using only gaseous deuterium at ambient temperatures (∼ 3 00 K ), allowing for continued reactor operations whilst parts of the cold source are unavailable or in maintenance. This is the first time such a stand-by feature has been incorporated into a cold source facility

Studies of neutron measurement methods for fusion plasma diagnostics

International Nuclear Information System (INIS)

Beimer, K.H.

1986-03-01

This thesis comprises several studies mainly devoted to neutron measurement systems for plasma diagnostics at JET (Joint European Torus). An in situ calibration of the U-235 fission chamber detectors located at JET is presented. These detectors are used for measuring the neutron yield from the thermonuclear reactions in the plasma. The energy spectrum of the neutrons from the reactions D(d,n) 3 He has been studied by means of a 3 He spectrometer. Especially, it was found that by measuring the width of the full energy peak in the response spectrum of the 3 He-spectrometer, the deuterium distribution in the deuterium targets used can be estimated. In order to measure different neutron energies it is necessary to obtain a detailed knowledge of the response of the spectrometer. Therefore, the response function to monoenergetic neutrons in the energy range 130-3030 keV was experimentally determined. Some work has been related to a design study of a 14 MeV spectrometer for neutron diagnostics. It is a combined proton-recoil and time-of-flight spectrometer for high resolution measurements. The main parts of it are the collimator, the scattering foil, and the detectors for the recoil protons and the scattered neutrons. The influence of proton straggling in the foil on the resolution and efficiency of the spectrometer has been studied. Furthermore, a three dimensional Monte Carlo code has been written and used for the design of the collimator. (author)

Microwave Ion Source and Beam Injection for an Accelerator-driven Neutron Source

International Nuclear Information System (INIS)

Vainionpaa, J.H.; Gough, R.; Hoff, M.; Kwan, J.W.; Ludewigt, B.A.; Regis, M.J.; Wallig, J.G.; Wells, R.

2007-01-01

An over-dense microwave driven ion source capable of producing deuterium (or hydrogen) beams at 100-200 mA/cm2 and with atomic fraction >90 percent was designed and tested with an electrostatic low energy beam transport section (LEBT). This ion source was incorporated into the design of an Accelerator Driven Neutron Source (ADNS). The other key components in the ADNS include a 6 MeV RFQ accelerator, a beam bending and scanning system, and a deuterium gas target. In this design a 40 mA D+ beam is produced from a 6 mm diameter aperture using a 60 kV extraction voltage. The LEBT section consists of 5 electrodes arranged to form 2 Einzel lenses that focus the beam into the RFQ entrance. To create the ECR condition, 2 induction coils are used to create ∼ 875 Gauss on axis inside the source chamber. To prevent HV breakdown in the LEBT a magnetic field clamp is necessary to minimize the field in this region. Matching of the microwave power from the waveguide to the plasma is done by an autotuner. We observed significant improvement of the beam quality after installing a boron nitride liner inside the ion source. The measured emittance data are compared with PBGUNS simulations

Microwave Ion Source and Beam Injection for an Accelerator-Driven Neutron Source

International Nuclear Information System (INIS)

Vainionpaa, J.H.; Gough, R.; Hoff, M.; Kwan, J.W.; Ludewigt, B.A.; Regis, M.J.; Wallig, J.G.; Wells, R.

2007-01-01

An over-dense microwave driven ion source capable of producing deuterium (or hydrogen) beams at 100-200 mA/cm 2 and with atomic fraction > 90% was designed and tested with an electrostatic low energy beam transport section (LEBT). This ion source was incorporated into the design of an Accelerator Driven Neutron Source (ADNS). The other key components in the ADNS include a 6 MeV RFQ accelerator, a beam bending and scanning system, and a deuterium gas target. In this design a 40 mA D + beam is produced from a 6 mm diameter aperture using a 60 kV extraction voltage. The LEBT section consists of 5 electrodes arranged to form 2 Einzel lenses that focus the beam into the RFQ entrance. To create the ECR condition, 2 induction coils are used to create ∼ 875 Gauss on axis inside the source chamber. To prevent HV breakdown in the LEBT a magnetic field clamp is necessary to minimize the field in this region. Matching of the microwave power from the waveguide to the plasma is done by an autotuner. They observed significant improvement of the beam quality after installing a boron nitride liner inside the ion source. The measured emittance data are compared with PBGUNS simulations

Accelerator driven neutron sources in Korea. Current and future

International Nuclear Information System (INIS)

Lee, Young-Ouk; Oh, Byung-Hoon; Hong, Bong-Geun; Chang, Jonghwa; Chang, Moon-Hee; Kim, Guinyun; Kim, Gi-Donng; Choi, Byung-Ho

2008-01-01

The Pohang Neutron Facility, based on a 65 MeV electron linear accelerator, has a neutron-gamma separation circuit, water-moderated tantalum target and 12 m TOF. It produces pulsed photonuclear neutrons with ≅2 μs width, 50 mA peak current and 15 Hz repetition, mainly for the neutron nuclear data production in up to keV energies. The Tandem Van de Graff at Korea Institute of Geoscience and Mineral Resources (KIGAM) is dedicated to measure MeV energy neutron capture and total cross section using TOF and prompt gamma ray detection system. The facility pulsed ≅10 8 mono-energetic neutrons/sec from 3 H(p,n) reaction with 1-2 ns width and 125 ns period. Korea Institute of Radiological and Medical Sciences (KIRAMS) has the MC50 medical cyclotron which accelerates protons up to an energy of 45 MeV and has several beam ports for proton or neutron irradiations. Beam current can be controlled from a few nano amperes to 50 uA. Korea Atomic Energy Research Institute (KAERI) has a plan to develop a neutron source by using 20 MeV electron accelerator. This photo-neutron source will be mainly used for nuclear data measurements based on time-of-flight experiments. A high intensity fast neutron source is also proposed to respond growing demands of fast neutrons, especially for the fusion material test. Throughput will be as high as several 10 13 neutrons/sec from D-T reaction powered by a high current (200 mA) ion source, a drive-in target and cooling systems, and closed circuit tritium ventilation/recovery systems. The Proton Engineering Frontier Project (PEFP) is developing a 100 MeV, 20 mA pulsed proton linear accelerator equipped with 5 target rooms, one of which is dedicated to produce neutrons using tungsten target. PEFP also proposes the 1-2 GeV rapid cycling synchrotron accelerator as an extension of the PEFP linac, which can be used for nuclear and high energy physics experiment, spallation neutron source, radioisotope, medical research, etc. (author)

Sweden to host a new neutron source

CERN Multimedia

Anaïs Schaeffer

2012-01-01

The first European neutron source, currently under development, should commence operations by the end of this decade. Its aim: to produce beams of neutrons that can penetrate into the heart of matter without damaging it and reveal its secrets.   An artist's impression of what the ESS should look like in 2019. At the southern end of Sweden, a town called Lund is preparing for the arrival of the world's most powerful neutron source: the European Spallation Source (ESS). Construction is scheduled to start at the beginning of next year, and the facility is expected to become operational by 2019, when it will produce its first neutron beams. “The ESS is the result of an idea that began 20 years ago!” underlines Mats Lindroos, in charge of the ESS Accelerator Division. “Today, 17 European countries support the project, including Sweden, Denmark and Norway, who together account for 50% of the construction funding.” The ESS, whose design is al...

The high-density Z-pinch as a pulsed fusion neutron source for fusion nuclear technology and materials testing

International Nuclear Information System (INIS)

Krakowski, R.A.; Sethian, J.D.; Hagenson, R.L.

1989-01-01

The dense Z-pinch (DZP) is one of the earliest and simplest plasma heating and confinement schemes. Recent experimental advances based on plasma initiation from hair-like (10s μm in radius) solid hydrogen filaments have so far not encountered the usually devastating MHD instabilities that plagued early DZP experiments. These encouraging results along with debt of a number of proof-of principle, high-current (1--2 MA in 10--100 ns) experiments have prompted consideration of the DZP as a pulsed source of DT fusion neutrons of sufficient strength (/dot S//sub N/ ≥ 10 19 n/s) to provide uncollided neutron fluxes in excess of I/sub ω/ = 5--10 MW/m 2 over test volumes of 10--30 litre or greater. While this neutron source would be pulsed (100s ns pulse widths, 10--100 Hz pulse rate), giving flux time compressions in the range 10 5 --10 6 , its simplicity, near-time feasibility, low cost, high-Q operation, and relevance to fusion systems that may provide a pulsed commercial end-product (e.g., inertial confinement or the DZP itself) together create the impetus for preliminary considerations as a neutron source for fusion nuclear technology and materials testings. The results of a preliminary parametric systems study (focusing primarily on physics issues), conceptual design, and cost versus performance analyses are presented. The DZP promises an expensive and efficient means to provide pulsed DT neutrons at an average rate in excess of 10 19 n/s, with neutron currents I/sub ω/ /approx lt/ 10 MW/m 2 over volumes V/sub exp/ ≥ 30 litre using single-pulse technologies that differ little from those being used in present-day experiments. 34 refs., 17 figs., 6 tabs

The Advanced Neutron Source liquid deuterium cold source

International Nuclear Information System (INIS)

Lucas, A.T.

1995-08-01

The Advanced Neutron Source will employ two cold sources to moderate neutrons to low energy (<10 meV). The cold neutrons produced are then passed through beam guides to various experiment stations. Each cold source moderator is a sphere of 410-mm internal diameter. The moderator material is liquid deuterium flowing at a rate of 1 kg/s and maintained at subcooled temperatures at all points of the circuit, to prevent boiling. Nuclear beat deposited within the liquid deuterium and its containment structure totals more than 30 kW. All of this heat is removed by the liquid deuterium, which raises its temperature by 5 K. The liquid prime mover is a cryogenic circulator that is situated in the return leg of the flow loop. This arrangement minimizes the heat added to the liquid between the heat exchanger and the moderator vessel, allowing the moderator to be operated at the minimum practical temperature. This report describes the latest thinking at the time of project termination. It also includes the status of various systems at that time and outlines anticipated directions in which the design would have progressed. In this regard, some detail differences between this report and official design documents reflect ideas that were not approved at the time of closure but are considered noteworthy

The Advanced Neutron Source

International Nuclear Information System (INIS)

Peretz, F.J.

1990-01-01

The Advanced Neutron Source (ANS) is to be a multipurpose neutron research center, constructed around a high-flux reactor now being designed at the Oak Ridge National Laboratory (ORNL). Its primary purpose is to place the United States in the forefront of neutron scattering in the twenty-first century. Other research programs include nuclear and fundamental physics, isotope production, materials irradiation, and analytical chemistry. The ANS will be a unique and invaluable research tool because of the unprecedented neutron flux available from the high-intensity research reactor. But this reactor would be ineffective without world-class research facilities that allow the fullest utilization of the available neutrons. And, in turn, those research facilities will not produce new and exciting science without a broad population of users from all parts of the nation and the world, placed in a stimulating environment in which experiments can be effectively conducted and in which scientific exchange is encouraged. This paper discusses the measures being taken to ensure that the design of the ANS focuses not only on the reactor, but on providing the experiment and user support facilities needed to allow its effective use

Proposal for the design of a small-angle neutron scattering facility at a pulsed neutron source

International Nuclear Information System (INIS)

Kley, W.

1980-01-01

The intensity-resolution-background considerations of an optimized small angle neutron scattering facility are reviewed for the special case of a pulsed neutron source. In the present proposal we conclude that for 'true elastic scattering experiments' filters can be used instead of expensive neutron guide tubes since low background conditions can be achieved by a combined action of filters as well as a proper time gating of the twodimensional detector. The impinging neutron beam is monochromatized by phasing a disk chopper to the neutron source pulses and in the scattered beam a second disk chopper is used to eliminate the inelastically scattered neutrons. Therefore, no time of fligh analysis is necessary for the scattered neutron intensity and true-elastic conditions are obtained by simply gating the two-dimensional detector. Considering a 4 m thick shield for the pulsed neutron source and choosing for optimum conditions a detector area element of (2.5 cm) 2 and a sample area of (1.25 cm) 2 , than for a minimum sample-detector-distance of 1.5 m, a maximum neutron source diameter of 6.67 cm is required in order to maintain always the optimum intensity- and resolution requirements

General-purpose readout electronics for white neutron source at China Spallation Neutron Source.

Science.gov (United States)

Wang, Q; Cao, P; Qi, X; Yu, T; Ji, X; Xie, L; An, Q

2018-01-01

The under-construction White Neutron Source (WNS) at China Spallation Neutron Source is a facility for accurate measurements of neutron-induced cross section. Seven spectrometers are planned at WNS. As the physical objectives of each spectrometer are different, the requirements for readout electronics are not the same. In order to simplify the development of the readout electronics, this paper presents a general method for detector signal readout. This method has advantages of expansibility and flexibility, which makes it adaptable to most detectors at WNS. In the WNS general-purpose readout electronics, signals from any kinds of detectors are conditioned by a dedicated signal conditioning module corresponding to this detector, and then digitized by a common waveform digitizer with high speed and high precision (1 GSPS at 12-bit) to obtain the full waveform data. The waveform digitizer uses a field programmable gate array chip to process the data stream and trigger information in real time. PXI Express platform is used to support the functionalities of data readout, clock distribution, and trigger information exchange between digitizers and trigger modules. Test results show that the performance of the WNS general-purpose readout electronics can meet the requirements of the WNS spectrometers.

Preliminary results of neutron production in Sahand plasma focus device

International Nuclear Information System (INIS)

Siahpoush, V.; Mohammadi, M.A.; Khorram, S.; Shabani, I.; Borhanian, J.; Ashrafi, S.; Naghshara, H.; Moslehi-Fard, M.; Sobhanian, S.

2004-01-01

We report in this paper the preliminary results of neutron generation during fusion reaction in deuterium in the Sahand Filipov type plasma focus, recently installed and put in operation at Tabriz University. The special calibration procedure for neutron detection system, using activation method is described

Characterization of the γ background in epithermal neutron scattering measurements at pulsed neutron sources

International Nuclear Information System (INIS)

Pietropaolo, A.; Tardocchi, M.; Schooneveld, E.M.; Senesi, R.

2006-01-01

This paper reports the characterization of the different components of the γ background in epithermal neutron scattering experiments at pulsed neutron sources. The measurements were performed on the VESUVIO spectrometer at ISIS spallation neutron source. These measurements, carried out with a high purity germanium detector, aim to provide detailed information for the investigation of the effect of the γ energy discrimination on the signal-to-background ratio. It is shown that the γ background is produced by different sources that can be identified with their relative time structure and relative weight

Neutron spectra characteristics for the intense neutron source, INS

International Nuclear Information System (INIS)

Battat, M.; Dierckx, R.; Emigh, C.R.

1977-01-01

The Intense Neutron Source, INS, facility is presently under construction at the Los Alamos Scientific Laboratory. Its purpose is to provide a broad base for research work related to the radiation effects produced by 14-MeV neutrons from a D-T burn of a fusion reactor. The INS facility produces a D-T burn-like reaction from the collision of an intense tritium-ion beam with a supersonic jet target of deuterium gas. The reaction produces a typical D-T 14-MeV neutron spectrum. By adding a fission blanket surrounding the D-T ''burn,'' the neutron spectral shape may be tailored to match almost perfectly the anticipated first-wall spectra from presently proposed fusion reactors. With a blanket in place, the total production of neutrons can be as large as 3 x 10 16 n/s and experimental volumes of the order of 1000 cm 3 can be available at flux levels greater than 0.6 x 10 14 n/cm 2 s

Anisotropy of neutron sources of Neutron Metrology Laboratory, IRD, Brazil; Anisotropia de fontes de neutrons do Laboratorio de Metrologia de Neutrons

Energy Technology Data Exchange (ETDEWEB)

Silva, A.C.F.; Silva, F.S.; Leite, S.P.; Creazolla, P.G; Patrão, K.C.S.; Fonseca, E.S. da; Fernandes, S.S.; Pereira, W.W., E-mail: Alexander.camargo@oi.com.br, E-mail: s.felippesouza@gmail.com, E-mail: karla@ird.gov.br, E-mail: walsan@ird.gov.br, E-mail: evaldo@ird.gov.br, E-mail: simonesilvafernandes@gmail.com, E-mail: prycyllacreazolla@gmail.com, E-mail: leitesprk@gmail.com [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Laboratorio Nacional de Metrologia; Fundação Técnico Educacional Souza Marques (FTESM), Rio de Janeiro, RJ (Brazil)

2017-11-01

The anisotropy measurements have as main objective to define the emission of the radiation by different angles of an encapsulated neutron source. The measurements were performed using a Long Accuracy Counter (PLC) Detector in the Low Dispersion Room of the LNMRI / IRD with different neutron sources. Each measurement was made using a support for the source, emulated through an arduino system to rotate it. The carrier is marked with a variation of 5 °, ranging from 0 ° to 360 °, for the work in question only half, 0 ° to 180 ° is used for a total of nineteen steps. In this paper three sources of {sup 241}AmBe (α, n) 5.92 GBq (16 Ci) were used, neutron sources having the following dimensions: 105 mm in height and 31 mm in diameter. The PLC was positioned at a distance of 2 meters from the neutron source and has a radius of 15 cm for the detection area. The anisotropy factor of the {sup 241}AmBe source was 17%. The results in this work will focus mainly on the area of radioprotection and studies that will improve the process of routine measurements in laboratories and instrument calibrations. (author)

Absolute calibration of the neutron yield measurement on JT-60 Upgrade

International Nuclear Information System (INIS)

Nishitani, Takeo; Takeuchi, Hiroshi; Barnes, C.W.

1991-10-01

Absolutely calibrated measurements of the neutron yield are important for the evaluation of the plasma performance such as the fusion gain Q in DD operating tokamaks. Total neutron yield is measured with 235 U and 238 U fission chambers and 3 He proportional counters in JT-60 Upgrade. The in situ calibration was performed by moving the 252 Cf neutron source toroidally through the JT-60 vacuum vessel. Detection efficiencies of three 235 U and two 3 He detectors were measured for 92 locations of the neutron point source in toroidal scans at two different major radii. The total detection efficiency for the torus neutron source was obtained by averaging the point efficiencies over the whole toroidal angle. The uncertainty of the resulting absolute plasma neutron source calibration is estimated to be ± 10%. (author)

Characterization of the neutron sources storage pool of the Neutron Standards Laboratory, using Montecarlo Techniques

International Nuclear Information System (INIS)

Campo Blanco, X.

2015-01-01

The development of irradiation damage resistant materials is one of the most important open fields in the design of experimental facilities and conceptual nucleoelectric fusion plants. The Neutron Standards Laboratory aims to contribute to this development by allowing the neutron irradiation of materials in its calibration neutron sources storage pool. For this purposes, it is essential to characterize the pool itself in terms of neutron fluence and spectra due to the calibration neutron sources. In this work, the main features of this facility are presented and the characterization of the storage pool is carried out. Finally, an application is shown of the obtained results to the neutron irradiation of material.

Neutron sources for neutrino investigations with the lithium converter

International Nuclear Information System (INIS)

Lyashuk, V.I.; Lutostansky, Yu.S.

2012-01-01

Creation of the powerful antineutrino source with a hard spectrum is possible on the base of β - -decay of the short lived 8 Li (T 1/2 = 0.84 s) isotope formed in the reaction 7 Li(n,γ) 8 Li. The 8 Li. isotope is a prime perspective antineutrino source taking into account that neutrino cross section depends as σ ∼ E ν 2 at the considered energy. The creation of this type powerful neutrino source (neutrino factory) is possible by (n,γ)-activation of high-purified 7 Li isotope under intensive neutron flux. As a neutron source for this purpose can be used the nuclear reactors (of steady-state flux and pulsed one), neutron sources on the base of accelerators and neutron generating targets, beam-dumps of large accelerators. The capabilities and perspectives of neutron sources are considered for the purpose of creation of the neutrino factory. Different realizations of lithium antineutrino sources (lithium converter on the base of high purified 7 Li isotope) are discussed: static regime (i.e., without transport of 8 Li isotope to the detector); dynamic regime (pumping of activated lithium to a remote detector in a closed cycle); lithium converter on the base of (a) a pulse reactors and (b) constructed as tandem of an antineutrino source and accelerator with a neutron-producing target. Heavy water solution of LiOD is proposed as a substance for the lithium converter. The expressions for neutrino fluxes in the detector position are obtained

New neutron cross sections for fusion materials studies

International Nuclear Information System (INIS)

Greenwood, L.R.; Smither, R.K.

1985-01-01

Neutron cross sections are being developed for a variety of fusion-related applications including neutron dosimetry, fusion plasma diagnostics, the activation of very long-lived isotopes, and high-energy accelerator neutron sources

THE SPALLATION NEUTRON SOURCE PROJECT - PHYSICAL CHALLENGES.

Energy Technology Data Exchange (ETDEWEB)

WEI,J.

2002-06-03

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.

Correlation of the neutron yield from the plasma focus upon variations in the magnetic field energy of the discharge circuit

Science.gov (United States)

Ablesimov, V. E.; Dolin, Yu. N.; Kalinychev, A. E.; Tsibikov, Z. S.

2017-10-01

The relation between neutron yield Y and magnetic field energy variations Δ W in the discharge circuit has been studied for a Mather-type plasma-focus camera. The activation technique (activation of silver isotopes) has been used to measure the integral yield of DD neutrons from the source. The time dependence of the neutron yield has been recorded by scintillation detectors. For the device used in the investigations, the neutron yield exhibits a linear dependence on variations in the magnetic field energy Δ W in the discharge circuit at the instant of neutron generation. It is also found that this dependence is related to the initial deuteron pressure in the discharge chamber.

Measurements of prompt gamma-rays from fast-neutron induced fission with the LICORNE directional neutron source

CERN Document Server

Wilson, J N; Halipre, P; Oberstedt, S; Oberstedt, A

2014-01-01

At the IPN Orsay we have developed a unique, directional, fast neutron source called LICORNE, intended initially to facilitate prompt fission gamma measurements. The ability of the IPN Orsay tandem accelerator to produce intense beams of $^7$Li is exploited to produce quasi-monoenergetic neutrons between 0.5 - 4 MeV using the p($^7$Li,$^7$Be)n inverse reaction. The available fluxes of up to 7 × 10$^7$ neutrons/second/steradian for the thickest hydrogen-rich targets are comparable to similar installations, but with two added advantages: (i) The kinematic focusing produces a natural neutron beam collimation which allows placement of gamma detectors adjacent to the irradiated sample unimpeded by source neutrons. (ii) The background of scattered neutrons in the experimental hall is drastically reduced. The dedicated neutron converter was commissioned in June 2013. Some preliminary results from the first experiment using the LICORNE neutron source at the IPN Orsay are presented. Prompt fission gamma rays from fas...

Deuterium Depth Profile in Neutron-Irradiated Tungsten Exposed to Plasma

International Nuclear Information System (INIS)

Shimada, Masashi; Cao, G.; Hatano, Y.; Oda, T.; Oya, Y.; Hara, M.; Calderoni, P.

2011-01-01

The effect of radiation damage has been mainly simulated using high-energy ion bombardment. The ions, however, are limited in range to only a few microns into the surface. Hence, some uncertainty remains about the increase of trapping at radiation damage produced by 14 MeV fusion neutrons, which penetrate much farther into the bulk material. With the Japan-US joint research project: Tritium, Irradiations, and Thermofluids for America and Nippon (TITAN), the tungsten samples (99.99 % pure from A.L.M.T., 6mm in diameter, 0.2mm in thickness) were irradiated to high flux neutrons at 50 C and to 0.025 dpa in the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL). Subsequently, the neutron-irradiated tungsten samples were exposed to a high-flux deuterium plasma (ion flux: 1021-1022 m-2s-1, ion fluence: 1025-1026 m-2) in the Tritium Plasma Experiment (TPE) at the Idaho National Laboratory (INL). First results of deuterium retention in neutron-irradiated tungsten exposed in TPE have been reported previously. This paper presents the latest results in our on-going work of deuterium depth profiling in neutron-irradiated tungsten via nuclear reaction analysis. The experimental data is compared with the result from non neutron-irradiated tungsten, and is analyzed with the Tritium Migration Analysis Program (TMAP) to elucidate the hydrogen isotope behavior such as retention and depth distribution in neutron-irradiated and non neutron-irradiated tungsten.

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

International Nuclear Information System (INIS)

Meadows, J.W.; Smith, D.L.

1980-05-01

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 data analysis purposes. Some results from these studies are presented, and a few specific examples of neutron-source-related corrections to cross section data are provided. 16 figures, 3 tables

Plasma focus project

International Nuclear Information System (INIS)

Sahlin, H.L.

1975-12-01

The primary objective of this project is to provide a relatively simple pulsed power source for high density pulsed fusion studies with a variety of DT and other fusion microexplosion targets. The plasma focus operated on DT at 1 MJ should produce greater than or equal to 10 15 DT neutrons per pulse corresponding to 2800 J of nuclear energy release and for low pressure operation and appropriately configured high Z anode center should yield an x-ray burst of about 1000 J with a substantial fraction of this x-ray energy concentrated in the 5-100 kV range. Because of its x-ray and neutron production potential, the operation of the focus as an x-ray source is also under study and an initial design study for a repetitively pulsed 1 MJ plasma focus as a pulsed neutron materials testing source has been completed. The plasma focus seems particularly appropriate for application as a materials testing source for pulsed fusion reactors, for example, based on laser driven fusion microexplosions. The construction status of the device is described

Steady state technologies for tokamak based fusion neutron sources and hybrids

International Nuclear Information System (INIS)

Azizov, E.A.; Kuteev, B.V.

2015-01-01

Full text of publication follows. The development of demonstration fusion neutron sources for fusion nuclear science activity and hybrid applications has reached the stage of conceptual design on the basis of tokamak device in Russia. The conceptual design of FNS-ST has been completed in details (plasma current 1.5 MA, magnetic field 1.5 T, major radius 0.5 m, aspect ratio 1.67 and auxiliary heating power up to 15 MW) [1, 2]. A comparison of physical plasma parameters and economics for FNS-ST and a conventional tokamak FNS-CT (plasma current 1.5 MA, magnetic field 6.7 T, major radius 2.25 m, aspect ratio 3 and auxiliary heating power up to 30 MW) has been fulfilled [3]. This study suggested the feasibility to reach 1-20 MW of fusion power using these magnetic configuration options. Nevertheless, the efficiency of neutron production Q remains comparable for both due to the beam fusion input. The total ST-economics for the full project including operation and utilization costs is by a factor of 2 better than of CT. Zero [4] and one-dimensional [5] models have been developed and used in this system analysis. The characteristics of plasma confinement, stability and current drive in operation have been confirmed by numerous benchmarking simulations of modern experiments. Scenarios allowing us to reach and maintain steady state operation have been considered and optimized. The results of these studies will be presented. Prospective technical solutions for SSO-technology systems have been evaluated, and the choice of enabling technologies and materials of the basic FNS options has been made. A conceptual design of a thin-wall water cooled vacuum chamber for heat loadings up to 1.5 MW/m 2 has been fulfilled. The chamber consists of 2 mm Be tiles, pre-shaped CuCrZr 1 mm shell and 1 mm of stainless steel shell as a structural material. A concept of double-null divertor for FNS-ST has been offered that is capable to withstand heat fluxes up to 6 MW/m 2 . Lithium dust

Optimization study of normal conductor tokamak for commercial neutron source

Science.gov (United States)

Fujita, T.; Sakai, R.; Okamoto, A.

2017-05-01

The optimum conceptual design of tokamak with normal conductor coils was studied for minimizing the cost for producing a given neutron flux by using a system code, PEC. It is assumed that the fusion neutrons are used for burning transuranics from the fission reactor spent fuel in the blanket and a fraction of the generated electric power is circulated to opearate the tokamak with moderate plasma fusion gain. The plasma performance was assumed to be moderate ones; {β\\text{N}}~∼ ~3{--}4 in the aspect ratio A~=~2{--}3 and {{H}98y2}~=~1 . The circulating power is an important factor affecting the cost. Though decreasing the aspect ratio is useful to raise the plasma beta and decrease the toroidal field, the maximum field in the coil starts to rise in the very low aspect ratio range and then the circulating power increases with decrease in the plasma aspect ratio A below A~∼ ~2 , while the construction cost increases with A . As a result, the cost per neutron has its minimum around A~∼ ~2.2 , namely, between ST and the conventional tokamak. The average circulating power fraction is expected to be ~51%.

Plasma focus neutron anisotropy measurements and influence of a deuteron beam obstacle

Energy Technology Data Exchange (ETDEWEB)

Talebitaher, A. [Physics Department, University of Regina, Saskatchewan, Canada S4S 0A2 (Canada); Springham, S.V., E-mail: stuart.springham@nie.edu.sg [Natural Sciences and Science Education, National Institute of Education, 637616 (Singapore); Rawat, R.S.; Lee, P. [Natural Sciences and Science Education, National Institute of Education, 637616 (Singapore)

2017-03-11

The deuterium-deuterium (DD) fusion neutron yield and anisotropy were measured on a shot-to-shot basis for the NX2 plasma focus (PF) device using two beryllium fast-neutron activation detectors at 0° and 90° to the PF axis. Measurements were performed for deuterium gas pressures in the range 6–16 mbar, and positive correlations between neutron yield and anisotropy were observed at all pressures. Subsequently, at one deuterium gas pressure (13 mbar), the contribution to the fusion yield produced by the forwardly-directed D{sup +} ion beam, emitted from the plasma pinch, was investigated by using a circular Pyrex plate to obstruct the beam and suppress its fusion contribution. Neutron measurements were performed with the obstacle positioned at two distances from the anode tip, and also without the obstacle. It was found that ~ 80% of the neutron yield originates in the plasma pinch column and just above that. In addition, proton pinhole imaging was performed from the 0° and 90° directions to the pinch. The obtained proton images are consistent with the conclusion that DD fusion is concentrated (~ 80%) in the pinch column region.

Development of the front end test stand and vessel for extraction and source plasma analyses negative hydrogen ion sources at the Rutherford Appleton Laboratory

Energy Technology Data Exchange (ETDEWEB)

Lawrie, S. R., E-mail: scott.lawrie@stfc.ac.uk [STFC ISIS Pulsed Spallation Neutron and Muon Facility, Rutherford Appleton Laboratory, Harwell Oxford, Harwell (United Kingdom); John Adams Institute of Accelerator Science, University of Oxford, Oxford (United Kingdom); Faircloth, D. C.; Letchford, A. P.; Perkins, M.; Whitehead, M. O.; Wood, T. [STFC ISIS Pulsed Spallation Neutron and Muon Facility, Rutherford Appleton Laboratory, Harwell Oxford, Harwell (United Kingdom); Gabor, C. [ASTeC Intense Beams Group, Rutherford Appleton Laboratory, Harwell Oxford, Harwell (United Kingdom); Back, J. [High Energy Physics Department, University of Warwick, Coventry (United Kingdom)

2014-02-15

The ISIS pulsed spallation neutron and muon facility at the Rutherford Appleton Laboratory (RAL) in the UK uses a Penning surface plasma negative hydrogen ion source. Upgrade options for the ISIS accelerator system demand a higher current, lower emittance beam with longer pulse lengths from the injector. The Front End Test Stand is being constructed at RAL to meet the upgrade requirements using a modified ISIS ion source. A new 10% duty cycle 25 kV pulsed extraction power supply has been commissioned and the first meter of 3 MeV radio frequency quadrupole has been delivered. Simultaneously, a Vessel for Extraction and Source Plasma Analyses is under construction in a new laboratory at RAL. The detailed measurements of the plasma and extracted beam characteristics will allow a radical overhaul of the transport optics, potentially yielding a simpler source configuration with greater output and lifetime.

Laser-driven x-ray and neutron source development for industrial applications of plasma accelerators

Science.gov (United States)

Brenner, C. M.; Mirfayzi, S. R.; Rusby, D. R.; Armstrong, C.; Alejo, A.; Wilson, L. A.; Clarke, R.; Ahmed, H.; Butler, N. M. H.; Haddock, D.; Higginson, A.; McClymont, A.; Murphy, C.; Notley, M.; Oliver, P.; Allott, R.; Hernandez-Gomez, C.; Kar, S.; McKenna, P.; Neely, D.

2016-01-01

Pulsed beams of energetic x-rays and neutrons from intense laser interactions with solid foils are promising for applications where bright, small emission area sources, capable of multi-modal delivery are ideal. Possible end users of laser-driven multi-modal sources are those requiring advanced non-destructive inspection techniques in industry sectors of high value commerce such as aerospace, nuclear and advanced manufacturing. We report on experimental work that demonstrates multi-modal operation of high power laser-solid interactions for neutron and x-ray beam generation. Measurements and Monte Carlo radiation transport simulations show that neutron yield is increased by a factor ~2 when a 1 mm copper foil is placed behind a 2 mm lithium foil, compared to using a 2 cm block of lithium only. We explore x-ray generation with a 10 picosecond drive pulse in order to tailor the spectral content for radiography with medium density alloy metals. The impact of using  >1 ps pulse duration on laser-accelerated electron beam generation and transport is discussed alongside the optimisation of subsequent bremsstrahlung emission in thin, high atomic number target foils. X-ray spectra are deconvolved from spectrometer measurements and simulation data generated using the GEANT4 Monte Carlo code. We also demonstrate the unique capability of laser-driven x-rays in being able to deliver single pulse high spatial resolution projection imaging of thick metallic objects. Active detector radiographic imaging of industrially relevant sample objects with a 10 ps drive pulse is presented for the first time, demonstrating that features of 200 μm size are resolved when projected at high magnification.

Laser-driven x-ray and neutron source development for industrial applications of plasma accelerators

International Nuclear Information System (INIS)

Brenner, C M; Rusby, D R; Armstrong, C; Wilson, L A; Clarke, R; Haddock, D; McClymont, A; Notley, M; Oliver, P; Allott, R; Hernandez-Gomez, C; Neely, D; Mirfayzi, S R; Alejo, A; Ahmed, H; Kar, S; Butler, N M H; Higginson, A; McKenna, P; Murphy, C

2016-01-01

Pulsed beams of energetic x-rays and neutrons from intense laser interactions with solid foils are promising for applications where bright, small emission area sources, capable of multi-modal delivery are ideal. Possible end users of laser-driven multi-modal sources are those requiring advanced non-destructive inspection techniques in industry sectors of high value commerce such as aerospace, nuclear and advanced manufacturing. We report on experimental work that demonstrates multi-modal operation of high power laser-solid interactions for neutron and x-ray beam generation. Measurements and Monte Carlo radiation transport simulations show that neutron yield is increased by a factor ∼2 when a 1 mm copper foil is placed behind a 2 mm lithium foil, compared to using a 2 cm block of lithium only. We explore x-ray generation with a 10 picosecond drive pulse in order to tailor the spectral content for radiography with medium density alloy metals. The impact of using  >1 ps pulse duration on laser-accelerated electron beam generation and transport is discussed alongside the optimisation of subsequent bremsstrahlung emission in thin, high atomic number target foils. X-ray spectra are deconvolved from spectrometer measurements and simulation data generated using the GEANT4 Monte Carlo code. We also demonstrate the unique capability of laser-driven x-rays in being able to deliver single pulse high spatial resolution projection imaging of thick metallic objects. Active detector radiographic imaging of industrially relevant sample objects with a 10 ps drive pulse is presented for the first time, demonstrating that features of 200 μm size are resolved when projected at high magnification. (paper)

Synchrotron based spallation neutron source concepts

International Nuclear Information System (INIS)

Cho, Y.

1998-01-01

During the past 20 years, rapid-cycling synchrotrons (RCS) have been used very productively to generate short-pulse thermal neutron beams for neutron scattering research by materials science communities in Japan (KENS), the UK (ISIS) and the US (IPNS). The most powerful source in existence, ISIS in the UK, delivers a 160-kW proton beam to a neutron-generating target. Several recently proposed facilities require proton beams in the MW range to produce intense short-pulse neutron beams. In some proposals, a linear accelerator provides the beam power and an accumulator ring compresses the pulse length to the required ∼ 1 micros. In others, RCS technology provides the bulk of the beam power and compresses the pulse length. Some synchrotron-based proposals achieve the desired beam power by combining two or more synchrotrons of the same energy, and others propose a combination of lower and higher energy synchrotrons. This paper presents the rationale for using RCS technology, and a discussion of the advantages and disadvantages of synchrotron-based spallation sources

A large angle cold neutron bender using sequential garland reflections for pulsed neutron source

Energy Technology Data Exchange (ETDEWEB)

Ebisawa, T.; Tasaki, S. [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst; Soyama, K.; Suzuki, J. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2001-03-01

We discuss a basic structure and performance of a new cold neutron bender using sequential garland reflections, in order to bend a neutron beam with large divergence by large angle. Using this bender for a pulsed neutron source we could not only avoid the frame overlap for cold neutrons but also install a plural spectrometers at a cold guide and obtain polarized neutron beams if necessary. (author)

A large angle cold neutron bender using sequential garland reflections for pulsed neutron source

International Nuclear Information System (INIS)

Ebisawa, T.; Tasaki, S.; Soyama, K.; Suzuki, J.

2001-01-01

We discuss a basic structure and performance of a new cold neutron bender using sequential garland reflections, in order to bend a neutron beam with large divergence by large angle. Using this bender for a pulsed neutron source we could not only avoid the frame overlap for cold neutrons but also install a plural spectrometers at a cold guide and obtain polarized neutron beams if necessary. (author)

Neutron sources and their characteristics

International Nuclear Information System (INIS)

McCall, R.C.; Swanson, W.P.

1979-03-01

The significant sources of photoneutrons within a linear-accelerator treatment head are identified and absolute estimates of neutron production per treatment dose are given for typical components. It is found that the high-Z materials within the treatment head do not significantly alter the neutron fluence but do substantially reduce the average energy of the transmitted spectrum. Reflection of neutrons from the concrete treatment room contribute to the neutron fluence, but not substantially to the patient integral dose, because of a further reduction in average energy. The ratio of maximum fluence to the treatment dose at the same distance is given as a function of electron energy. This ratio rises with energy to an almost constant value of 2.1 x 10 5 neutrons cm -2 rad -1 at electron energies above about 25 MeV. Measured data obtained at a variety of accelerator installations are presented and compared with these calculations. Reasons for apparent deviations are suggested. Absolute depth-dose and depth-dose-equivalent distributions for realistic neutron spectra that occur at therapy installations are calculated, and a rapid falloff with depth is found. The ratio of neutron integral absorbed dose to leakage photon absorbed dose is estimated to be 0.04 and 0.2 for 14 to 25 MeV incident electron energy, respectively. Possible reasons are given for lesser neutron production from betatrons than from linear accelerators. Possible ways in which neutron production can be reduced are discussed

Method to determine the strength of a neutron source

Energy Technology Data Exchange (ETDEWEB)

Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M.; Chacon R, A.; Mercado, G.A. [UAZ, A.P. 336, 98000 Zacatecas (Mexico); Gallego, E.; Lorente, A. [Depto. Ingenieria Nuclear, Universidad Politecnica de Madrid, (Spain)

2006-07-01

The use of a gamma-ray spectrometer with a 3 {phi} x 3 NaI(Tl) detector, with a moderator sphere has been studied in the aim to measure the neutron fluence rate and to determine the source strength. Moderators with a large amount of hydrogen are able to slowdown and thermalize neutrons; once thermalized there is a probability that thermal neutron to be captured by hydrogen producing 2.22 MeV prompt gamma-ray. The pulse-height spectrum collected in a multicharmel analyzer shows a photopeak around 2.22 MeV whose net area is proportional to total neutron fluence rate and to the neutron source strength. The characteristics of this system were determined by a Monte Carlo study using the MCNP 4C code, where a detailed model of the Nal(Tl) was utilized. As moderators 3, 5, and 10 inches-diameter spheres where utilized and the response was calculated for monoenergetic and isotopic neutrons sources. (Author)

Research applications of the Livermore RTNS-II neutron sources

International Nuclear Information System (INIS)

Davis, J.C.

1978-01-01

The Lawrence Livermore Laboratory has completed construction of the Rotating Target Neutron Source-II (RTNS-II) Facility. These sources, built and operated for the Office of Fusion Energy of the Department of Energy, will be operated by LLL as a national facility for the study of materials damage processes induced by 14-MeV neutrons. Design strength of the sources is 4 x 10 13 n/s with a maximum flux of 1 X 10 13 n/cm 2 s. The 400 keV, 150 mA D + accelerators and 5000 rpm titanium--tritide target assemblies were built using experience gained with LLL's RTNS-I neutron source. The RTNS-I source, producing 6 x 10 12 n/s, is currently the most intense 14-MeV source available. RTNS-I has been used for fusion reactor materials studies for the past six years. The experimental program for the new sources will be oriented toward fundamental measurements of high energy neutron-induced effects. The data produced will be used to develop models of damage processes to help guide materials selection for future fusion reactors

The cold neutron source in DR 3

International Nuclear Information System (INIS)

Jensen, K.; Leth, j.A.

1980-09-01

A description of the cold neutron source in DR 3 is given. The moderator of the cold neutron source is supercritical hydrogen at about 30degK and 15 bar abs. The necessary cooling capacity is supplied by two Philips Stirling B20 cryogenerators. The hydrogen is circulated between the cryogenerators and the in-pile moderator chamber by small fans. The safety of the facility is based on the use of triple containment preventing contact between hydrogen and air. The triple containment is achieved by enclosing the high vacuum system, surrounging the hydrogen system, in a helium blanket. The achieved spectrum of the thermal neutron flux and the gain factor are given as well as the experience from more than 5 years of operation. Finally some work on extension of the facility to operate two cold sources is reported. (author)

Development of Cold Neutron Activation Station at HANARO Cold Neutron Source

International Nuclear Information System (INIS)

Sun, G. M.; Hoang, S. M. T.; Moon, J. H.; Chung, Y. S.; Cho, S. J.; Lee, K. H.; Park, B. G.; Choi, H. D.

2012-01-01

A new cold neutron source at the HANARO Research Reactor had been constructed in the framework of a five-year project, and ended in 2009. It has seven neutron guides, among which five guides were already allocated for a number of neutron scattering instruments. A new two-year project to develop a Cold Neutron Activation Station (CONAS) was carried out at the two neutron guides since May 2010, which was supported by the program of the Ministry of Education, Science and Technology, Korea. Fig. 1 shows the location of CONAS. CONAS is a complex facility including several radioanalytical instruments utilizing neutron capture reaction to analyze elements in a sample. It was designed to include three instruments like a CN-PGAA (Cold Neutron - Prompt Gamma Activation Analysis), a CN-NIPS (Cold Neutron - Neutron Induced Pair Spectrometer), and a CN-NDP (Cold Neutron - Neutron-induced prompt charged particle Depth Profiling). Fig. 2 shows the conceptual configuration of the CONAS concrete bioshield and the instruments. CN-PGAA and CN-NIPS measure the gamma-rays promptly emitted from the sample after neutron capture, whereas CN-NDP is a probe to measure the charged particles emitted from the sample surface after neutron capture. For this, we constructed two cold neutron guides called CG1 and CG2B guides from the CNS

Concrete shielding of neutron radiations of plasma focus and dose examination by FLUKA

Science.gov (United States)

Nemati, M. J.; Amrollahi, R.; Habibi, M.

2013-07-01

Plasma Focus (PF) is among those devices which are used in plasma investigations, but this device produces some dangerous radiations after each shot, which generate a hazardous area for the operators of this device; therefore, it is better for the operators to stay away as much as possible from the area, where plasma focus has been placed. In this paper FLUKA Monte Carlo simulation has been used to calculate radiations produced by a 4 kJ Amirkabir plasma focus device through different concrete shielding concepts with various thicknesses (square, labyrinth and cave concepts). The neutron yield of Amirkabir plasma focus at varying deuterium pressure (3-9 torr) and two charging voltages (11.5 and 13.5 kV) is (2.25 ± 0.2) × 108 neutrons/shot and (2.88 ± 0.29) × 108 neutrons/shot of 2.45 MeV, respectively. The most influential shield for the plasma focus device among these geometries is the labyrinth concept on four sides and the top with 20 cm concrete.

Design and Demonstration of a Material-Plasma Exposure Target Station for Neutron Irradiated Samples

Energy Technology Data Exchange (ETDEWEB)

Rapp, Juergen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Aaron, A. M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bell, Gary L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Burgess, Thomas W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ellis, Ronald James [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Giuliano, D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kiggans, James O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lessard, Timothy L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ohriner, Evan Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Perkins, Dale E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Varma, Venugopal Koikal [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-10-20

Fusion energy is the most promising energy source for the future, and one of the most important problems to be solved progressing to a commercial fusion reactor is the identification of plasma-facing materials compatible with the extreme conditions in the fusion reactor environment. The development of plasma–material interaction (PMI) science and the technology of plasma-facing components are key elements in the development of the next step fusion device in the United States, the so-called Fusion Nuclear Science Facility (FNSF). All of these PMI issues and the uncertain impact of the 14-MeV neutron irradiation have been identified in numerous expert panel reports to the fusion community. The 2007 Greenwald report classifies reactor plasma-facing materials (PFCs) and materials as the only Tier 1 issues, requiring a “. . . major extrapolation from the current state of knowledge, need for qualitative improvements and substantial development for both the short and long term.” The Greenwald report goes on to list 19 gaps in understanding and performance related to the plasma–material interface for the technology facilities needed for DEMO-oriented R&D and DEMO itself. Of the 15 major gaps, six (G7, G9, G10, G12, G13) can possibly be addressed with ORNL’s proposal of an advanced Material Plasma Exposure eXperiment. Establishing this mid-scale plasma materials test facility at ORNL is a key element in ORNL’s strategy to secure a leadership role for decades of fusion R&D. That is to say, our end goal is to bring the “signature facility” FNSF home to ORNL. This project is related to the pre-conceptual design of an innovative target station for a future Material–Plasma Exposure eXperiment (MPEX). The target station will be designed to expose candidate fusion reactor plasma-facing materials and components (PFMs and PFCs) to conditions anticipated in fusion reactors, where PFCs will be exposed to dense high-temperature hydrogen plasmas providing steady

Subcriticality calculation in nuclear reactors with external neutron sources

Energy Technology Data Exchange (ETDEWEB)

Silva, Adilson Costa da; Martinez, Aquilino Senra; Silva, Fernando Carvalho da [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Engenharia Nuclear]. E-mails: asilva@con.ufrj.br; aquilino@lmp.ufrj.br; fernando@con.ufrj.br

2007-07-01

The main objective of this paper consists on the development of a methodology to monitor subcriticality. We used the inverse point kinetic equation with 6 precursor groups and external neutron sources for the calculation of reactivity. The input data for the inverse point kinetic equation was adjusted, in order to use the neutron counting rates obtained from the subcritical multiplication (1/M) in a nuclear reactor. In this paper, we assumed that the external neutron sources strength is constant and we define it in terms of a known initial condition. The results obtained from inverse point kinetic equation with external neutron sources were compared with the results obtained with a benchmark calculation, and showed good accuracy (author)

Subcriticality calculation in nuclear reactors with external neutron sources

International Nuclear Information System (INIS)

Silva, Adilson Costa da; Martinez, Aquilino Senra; Silva, Fernando Carvalho da

2007-01-01

The main objective of this paper consists on the development of a methodology to monitor subcriticality. We used the inverse point kinetic equation with 6 precursor groups and external neutron sources for the calculation of reactivity. The input data for the inverse point kinetic equation was adjusted, in order to use the neutron counting rates obtained from the subcritical multiplication (1/M) in a nuclear reactor. In this paper, we assumed that the external neutron sources strength is constant and we define it in terms of a known initial condition. The results obtained from inverse point kinetic equation with external neutron sources were compared with the results obtained with a benchmark calculation, and showed good accuracy (author)

Moderator materials for the Spallation Neutron Source

International Nuclear Information System (INIS)

Charlton, L.A.

1999-01-01

The Spallation Neutron Source (SNS) is a neutron source providing intense neutron fluxes that will be used for performing a large variety of neutron scattering experiments. SNS is to be completed and start operation in 2005. Protons will be accelerated to 1 GeV, stored in an accumulator ring, and then injected into a neutron-producing target. After leaving the target (Hg in the ca/se of SNS), the neutrons are prepared for experiments by first using a moderator to impose energy and width requirements on the neutron pulse. One of the most important ingredients is the moderator material. Four materials that are commonly used and that were considered for use in SNS are liquid hydrogen (L-H 2 ), liquid water (L-H 2 O), liquid methane (L-CH 4 ), and solid methane (S-CH 4 ). The spectra (neutron current versus neutron energy) for these four materials are shown. As may be seen, at low neutron energies ( 4 , which produces up to four times as many neutrons in this energy range as L-H 2 . The problem with the material is the internal storage of energy that can be spontaneously and explosively released. At energies of just above 10 MeV, the most effective moderator material is L-CH 4 . Polymerization problems, however, preclude its use at high powers (again such as in SNS), where the buildup of undesirable materials becomes prohibitive. This is, however, an important energy range for neutron experiments. Preliminary consideration is being given to a composite moderator that contains two adjacent sections, one of L-H 2 and one of L-H 2 O, which produces a spectrum that is very similar to L-CH 4

Thermal neutron equivalent doses assessment around KFUPM neutron source storage area using NTDs

Energy Technology Data Exchange (ETDEWEB)

Abu-Jarad, F.; Fazal-ur-Rehman; Al-Haddad, M.N.; Al-Jarrallah, M.I.; Nassar, R

2002-07-01

Area passive neutron dosemeters based on nuclear track detectors (NTDs) have been used for 13 days to assess accumulated low doses of thermal neutrons around neutron source storage area of the King Fahd University of Petroleum and Minerals (KFUPM). Moreover, the aim of this study is to check the effectiveness of shielding of the storage area. NTDs were mounted with the boron converter on their surface as one compressed unit. The converter is a lithium tetraborate (Li{sub 2}B{sub 4}O{sub 7}) layer for thermal neutron detection via {sup 10}B(N,{alpha}){sup 7}Li and {sup 6}Li(n,{alpha}){sup 3}H nuclear reactions. The area passive dosemeters were installed on 26 different locations around the source storage area and adjacent rooms. The calibration factor for NTD-based area passive neutron dosemeters was found to be 8.3 alpha tracks.cm{sup -2}.{mu}Sv{sup -1} using active snoopy neutron dosemeters in the KFUPM neutron irradiation facility. The results show the variation of accumulated dose with locations around the storage area. The range of dose rates varied from as low as 40 nSv.h{sup -1} up to 11 {mu}Sv.h{sup -1}. The study indicates that the area passive neutron dosemeter was able to detect accumulated doses as low as 40 nSv.h{sup -1}, which could not be detected with the available active neutron dosemeters. The results of the study also indicate that an additional shielding is required to bring the dose rates down to background level. The present investigation suggests extending this study to find the contribution of doses from fast neutrons around the neutron source storage area using NTDs through proton recoil. The significance of this passive technique is that it is highly sensitive and does not require any electronics or power supplies, as is the case in active systems. (author)

Polarisation modulated crosscorrelation spectroscopy on a pulsed neutron source

International Nuclear Information System (INIS)

Cywinski, R.; Williams, W.G.

1984-07-01

A crosscorrelation technique is introduced by which a total scattering polarisation analysis spectrometer on a pulsed neutron source can be modified to give full neutron polarisation and energy analysis without changing the physical configuration of the instrument. Its implementation on the proposed POLARIS spectrometer at the Rutherford Appleton Laboratory Spallation Neutron Source is described, and the expected dynamic (Q, ω) range and resolution evaluated. (author)

Compact neutron generator with nanotube ion source

Science.gov (United States)

Chepurnov, A. S.; Ionidi, V. Y.; Ivashchuk, O. O.; Kirsanov, M. A.; Kitsyuk, E. P.; Klenin, A. A.; Kubankin, A. S.; Nazhmudinov, R. M.; Nikulin, I. S.; Oleinik, A. N.; Pavlov, A. A.; Shchagin, A. V.; Zhukova, P. N.

2018-02-01

In this letter, we report the observation of fast neutrons generated when a positive acceleration potential is applied to an array of orientated carbon nanotubes, which are used as an ion source. The neutrons with energy of 2.45 MeV are generated as a result of D-D fusion reaction. The dependencies of the neutron yield on the value of the applied potential and residual pressure of deuterium are measured. The proposed approach is planned to be used for the development of compact neutron generators.

A new large-scale plasma source with plasma cathode

International Nuclear Information System (INIS)

Yamauchi, K.; Hirokawa, K.; Suzuki, H.; Satake, T.

1996-01-01

A new large-scale plasma source (200 mm diameter) with a plasma cathode has been investigated. The plasma has a good spatial uniformity, operates at low electron temperature, and is highly ionized under relatively low gas pressure of about 10 -4 Torr. The plasma source consists of a plasma chamber and a plasma cathode generator. The plasma chamber has an anode which is 200 mm in diameter, 150 mm in length, is made of 304 stainless steel, and acts as a plasma expansion cup. A filament-cathode-like plasma ''plasma cathode'' is placed on the central axis of this source. To improve the plasma spatial uniformity in the plasma chamber, a disk-shaped, floating electrode is placed between the plasma chamber and the plasma cathode. The 200 mm diameter plasma is measure by using Langmuir probes. As a result, the discharge voltage is relatively low (30-120 V), the plasma space potential is almost equal to the discharge voltage and can be easily controlled, the electron temperature is several electron volts, the plasma density is about 10 10 cm -3 , and the plasma density is about 10% variance in over a 100 mm diameter. (Author)

Problems in the neutron dynamics of source-driven systems

International Nuclear Information System (INIS)

Ravetto, P.

2001-01-01

The present paper presents some neutronic features of source-driven neutron multiplying systems, with special regards to dynamics, discussing the validity and limitations of classical methods, developed for systems in the vicinity of criticality. Specific characteristics, such as source dominance and the role of delayed neutron emissions are illustrated. Some dynamic peculiarities of innovative concepts proposed for accelerator-driven systems, such as fluid-fuel, are also discussed. The second portion of the work formulates the quasi-static methods for source-driven systems, evidencing its novel features and presenting some numerical results. (author)

21 CFR 640.60 - Source Plasma.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Source Plasma. 640.60 Section 640.60 Food and... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Source Plasma § 640.60 Source Plasma. The proper name of the product shall be Source Plasma. The product is defined as the fluid portion of human blood...

Experimental study of a fast plasma focus discharge operated in the range of tens of joules emitting neutrons

International Nuclear Information System (INIS)

Tarifeno Saldivia, Eriel Esteban

2011-01-01

In this doctoral research, a small plasma focus discharge operated at tens of joules and kilo amperes has been experimentally studied. This device produces a coaxial discharge by an electrode arrange which consists of an inner electrode, a cylindrical insulator, and an outer electrode. The discharge is driven by a capacitive generator and it is operated at pressures of some millibars. Typical electrical parameters of the device are T/4∼150ns, 160 nF, 40 nH, 30-100J, 40-70kA. When Deuterium is used as filling gas, neutrons are produced by fusion reactions. The device, namely PF-50J, is one of the most extreme plasma focus reported in the literature to emit neutrons. The results of this work have demonstrated that the same dynamics found in larger machines (operated from kJ to MJ) is also found in this extremely low energy device which means that after the discharge is initiated, a plasma sheet is formed over the insulator. By the action of the Lorentz force, the plasma sheet moves axially. When the sheet reaches the top end of the inner electrode, it starts to implode radially to finally form a dense plasma column (pinch). Finally, the plasma column is disrupted 5-10ns after column formation. Shock piston velocities of the order of 10 4 -10 5 m/s were estimated from experiments for each discharge dynamical phase. Typical pinch densities of 10 24-25 m -3 were also observed in PF-50J. An interesting feature observed in this work is the formation of axial jet-like structures which appears at late times almost hundred nanoseconds after pinch disruption. These structures are composed by a metallic plasma which results from ablation of the inner electrode. The mechanism responsible for the formation of this kind of structure is still unknown, although evidence suggests that the phenomena is not related to the pinch formation process. One of the principal motivations of this thesis was to study the optimization for neutron emission in the PF-50J device. This plasma focus

Virtual Gamma Ray Radiation Sources through Neutron Radiative Capture

Energy Technology Data Exchange (ETDEWEB)

Scott Wilde, Raymond Keegan

2008-07-01

The countrate response of a gamma spectrometry system from a neutron radiation source behind a plane of moderating material doped with a nuclide of a large radiative neutron capture cross-section exhibits a countrate response analogous to a gamma radiation source at the same position from the detector. Using a planar, surface area of the neutron moderating material exposed to the neutron radiation produces a larger area under the prompt gamma ray peak in the detector than a smaller area of dimensions relative to the active volume of the gamma detection system.

Neutron calibration sources in the Daya Bay experiment

Energy Technology Data Exchange (ETDEWEB)

Liu, J., E-mail: jianglai.liu@sjtu.edu.cn [Department of Physics, Shanghai Jiao Tong University, Shanghai (China); Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Carr, R. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Dwyer, D.A. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Gu, W.Q. [Department of Physics, Shanghai Jiao Tong University, Shanghai (China); Li, G.S., E-mail: lgs1029@sjtu.edu.cn [Department of Physics, Shanghai Jiao Tong University, Shanghai (China); McKeown, R.D. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Department of Physics, College of William and Mary, Williamsburg, VA (United States); Qian, X. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Brookhaven National Laboratory, Upton, NY (United States); Tsang, R.H.M. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487 (United States); Wu, F.F. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Zhang, C. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Brookhaven National Laboratory, Upton, NY (United States)

2015-10-11

We describe the design and construction of the low rate neutron calibration sources used in the Daya Bay Reactor Anti-neutrino Experiment. Such sources are free of correlated gamma-neutron emission, which is essential in minimizing induced background in the anti-neutrino detector. The design characteristics have been validated in the Daya Bay anti-neutrino detector.

Neutron calibration sources in the Daya Bay experiment

International Nuclear Information System (INIS)

Liu, J.; Carr, R.; Dwyer, D.A.; Gu, W.Q.; Li, G.S.; McKeown, R.D.; Qian, X.; Tsang, R.H.M.; Wu, F.F.; Zhang, C.

2015-01-01

We describe the design and construction of the low rate neutron calibration sources used in the Daya Bay Reactor Anti-neutrino Experiment. Such sources are free of correlated gamma-neutron emission, which is essential in minimizing induced background in the anti-neutrino detector. The design characteristics have been validated in the Daya Bay anti-neutrino detector

Assessment of the gas dynamic trap mirror facility as intense neutron source for fusion material test irradiations

International Nuclear Information System (INIS)

Fischer, U.; Moeslang, A.; Ivanov, A.A.

2000-01-01

The gas dynamic trap (GDT) mirror machine has been proposed by the Budker Institute of nuclear physics, Novosibirsk, as a volumetric neutron source for fusion material test irradiations. On the basis of the GDT plasma confinement concept, 14 MeV neutrons are generated at high production rates in the two end sections of the axially symmetrical central mirror cell, serving as suitable irradiation test regions. In this paper, we present an assessment of the GDT as intense neutron source for fusion material test irradiations. This includes comparisons to irradiation conditions in fusion reactor systems (ITER, Demo) and the International Fusion Material Irradiation Facility (IFMIF), as well as a conceptual design for a helium-cooled tubular test assembly elaborated for the largest of the two test zones taking proper account of neutronics, thermal-hydraulic and mechanical aspects. This tubular test assembly incorporates ten rigs of about 200 cm length used for inserting instrumented test capsules with miniaturized specimens taking advantage of the 'small specimen test technology'. The proposed design allows individual temperatures in each of the rigs, and active heating systems inside the capsules ensures specimen temperature stability even during beam-off periods. The major concern is about the maximum achievable dpa accumulation of less than 15 dpa per full power year on the basis of the present design parameters of the GDT neutron source. A design upgrading is proposed to allow for higher neutron wall loadings in the material test regions

Compact deuterium-tritium neutron generator using a novel field ionization source

Energy Technology Data Exchange (ETDEWEB)

Ellsworth, J. L., E-mail: ellsworth7@llnl.gov; Falabella, S.; Sanchez, J.; Tang, V. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States); Wang, H. [Department of Computer Science, Stanford University, Stanford, California 94305 (United States)

2014-11-21

Active interrogation using neutrons is an effective method for detecting shielded nuclear material. A lightweight, lunch-box-sized, battery-operated neutron source would enable new concepts of operation in the field. We have developed at-scale components for a highly portable, completely self-contained, pulsed Deuterium-Tritium (DT) neutron source producing 14 MeV neutrons with average yields of 10{sup 7} n/s. A gated, field ionization ion source using etched electrodes has been developed that produces pulsed ion currents up to 500 nA. A compact Cockcroft-Walton high voltage source is used to accelerate deuterons into a metal hydride target for neutron production. The results of full scale DT tests using the field ionization source are presented.

Conventional sources of fast neutrons in 'cold fusion' experiments

International Nuclear Information System (INIS)

Cribier, M.; Spiro, M.; Favier, J.

1989-04-01

In 'cold fusion' experiments with heavy water a source of neutrons is the dissociation of deuterium induced by alpha particles emitted by natural occurring radioisotopes. We evaluate the rate of fast neutron emission as a function of the concentration of U, Th, Rn in contact with deuterium and discuss the possibility that the neutrons claimed to have been observed in 'cold fusion' experiments could be due to this conventional source

Estimation of low-level neutron dose-equivalent rate by using extrapolation method for a curie level Am–Be neutron source

International Nuclear Information System (INIS)

Li, Gang; Xu, Jiayun; Zhang, Jie

2015-01-01

Neutron radiation protection is an important research area because of the strong radiation biological effect of neutron field. The radiation dose of neutron is closely related to the neutron energy, and the connected relationship is a complex function of energy. For the low-level neutron radiation field (e.g. the Am–Be source), the commonly used commercial neutron dosimeter cannot always reflect the low-level dose rate, which is restricted by its own sensitivity limit and measuring range. In this paper, the intensity distribution of neutron field caused by a curie level Am–Be neutron source was investigated by measuring the count rates obtained through a 3 He proportional counter at different locations around the source. The results indicate that the count rates outside of the source room are negligible compared with the count rates measured in the source room. In the source room, 3 He proportional counter and neutron dosimeter were used to measure the count rates and dose rates respectively at different distances to the source. The results indicate that both the count rates and dose rates decrease exponentially with the increasing distance, and the dose rates measured by a commercial dosimeter are in good agreement with the results calculated by the Geant4 simulation within the inherent errors recommended by ICRP and IEC. Further studies presented in this paper indicate that the low-level neutron dose equivalent rates in the source room increase exponentially with the increasing low-energy neutron count rates when the source is lifted from the shield with different radiation intensities. Based on this relationship as well as the count rates measured at larger distance to the source, the dose rates can be calculated approximately by the extrapolation method. This principle can be used to estimate the low level neutron dose values in the source room which cannot be measured directly by a commercial dosimeter. - Highlights: • The scope of the affected area for

An ultra-cold neutron source at the MLNSC

International Nuclear Information System (INIS)

Bowles, T.J.; Brun, T.; Hill, R.; Morris, C.; Seestrom, S.J.; Crow, L.; Serebrov, A.

1998-01-01

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

An ultra-cold neutron source at the MLNSC

Energy Technology Data Exchange (ETDEWEB)

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

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.

GEM-based thermal neutron beam monitors for spallation sources

International Nuclear Information System (INIS)

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.

2013-01-01

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 3 He 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 1μm thick B 4 C layer used to convert thermal neutrons to charged particles through the 10 B(n, 7 Li)α nuclear reaction. This paper describes the results obtained by testing a bGEM detector at the ISIS spallation source on the VESUVIO beamline. Beam profiles (FWHM x =31 mm and FWHM y =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 3 He-based gaseous detectors

Prediction of the neutrons subcritical multiplication using the diffusion hybrid equation with external neutron sources

Energy Technology Data Exchange (ETDEWEB)

Costa da Silva, Adilson; Carvalho da Silva, Fernando [COPPE/UFRJ, Programa de Engenharia Nuclear, Caixa Postal 68509, 21941-914, Rio de Janeiro (Brazil); Senra Martinez, Aquilino, E-mail: aquilino@lmp.ufrj.br [COPPE/UFRJ, Programa de Engenharia Nuclear, Caixa Postal 68509, 21941-914, Rio de Janeiro (Brazil)

2011-07-15

Highlights: > We proposed a new neutron diffusion hybrid equation with external neutron source. > A coarse mesh finite difference method for the adjoint flux and reactivity calculation was developed. > 1/M curve to predict the criticality condition is used. - Abstract: We used the neutron diffusion hybrid equation, in cartesian geometry with external neutron sources to predict the subcritical multiplication of neutrons in a pressurized water reactor, using a 1/M curve to predict the criticality condition. A Coarse Mesh Finite Difference Method was developed for the adjoint flux calculation and to obtain the reactivity values of the reactor. The results obtained were compared with benchmark values in order to validate the methodology presented in this paper.

Prediction of the neutrons subcritical multiplication using the diffusion hybrid equation with external neutron sources

International Nuclear Information System (INIS)

Costa da Silva, Adilson; Carvalho da Silva, Fernando; Senra Martinez, Aquilino

2011-01-01

Highlights: → We proposed a new neutron diffusion hybrid equation with external neutron source. → A coarse mesh finite difference method for the adjoint flux and reactivity calculation was developed. → 1/M curve to predict the criticality condition is used. - Abstract: We used the neutron diffusion hybrid equation, in cartesian geometry with external neutron sources to predict the subcritical multiplication of neutrons in a pressurized water reactor, using a 1/M curve to predict the criticality condition. A Coarse Mesh Finite Difference Method was developed for the adjoint flux calculation and to obtain the reactivity values of the reactor. The results obtained were compared with benchmark values in order to validate the methodology presented in this paper.

Performance of a reflectometer at continuous wave and pulsed neutron sources

International Nuclear Information System (INIS)

Fitzsimmons, M.R.

1995-01-01

The Monte-Carlo simulations presented here involve simulations of reflectivity measurements of one sample using a reflectometer of traditional geometry at different neutron sources. The same reflectometer was used in all simulations. Only the characteristics of the neutron source, and the technique used to measure neutron wavelength were changed. In the case of the CW simulation, a monochromating crystal was used to select a nearly monochromatic beam (MB) from the neutron spectrum. In the simulations of the pulse sources, the time needed to traverse a fixed distance was measured, from which neutron wavelength is deduced

Neutron generator tube ion source control apparatus

International Nuclear Information System (INIS)

Bridges, J.R.

1982-01-01

A pulsed neutron well logging system includes a neutron generator tube of the deuterium-tritium accelerator type and an ion source control apparatus providing extremely sharply time-defined neutron pulses. A low voltage control pulse supplied to an input by timing circuits turns a power FET on via a buffer-driver whereby a 2000 volt pulse is produced in the secondary of a pulse transformer and applied to the ion source of the tube. A rapid fall in this ion source control pulse is ensured by a quenching circuit wherein a one-shot responds to the falling edge of the control pulse and produces a 3 microsecond delay to compensate for the propagation delay. A second one-shot is triggered by the falling edge of the output of the first one-shot and gives an 8 microsecond pulse to turn on the power FET which, via an isolation transformer turns on a series-connected transistor to ground the secondary of the pulse transformer and the ion source. (author)

The comparison of four neutron sources for Prompt Gamma Neutron Activation Analysis (PGNAA) in vivo detections of boron.

Science.gov (United States)

Fantidis, J G; Nicolaou, G E; Potolias, C; Vordos, N; Bandekas, D V

A Prompt Gamma Ray Neutron Activation Analysis (PGNAA) system, incorporating an isotopic neutron source has been simulated using the MCNPX Monte Carlo code. In order to improve the signal to noise ratio different collimators and a filter were placed between the neutron source and the object. The effect of the positioning of the neutron beam and the detector relative to the object has been studied. In this work the optimisation procedure is demonstrated for boron. Monte Carlo calculations were carried out to compare the performance of the proposed PGNAA system using four different neutron sources ( 241 Am/Be, 252 Cf, 241 Am/B, and DT neutron generator). Among the different systems the 252 Cf neutron based PGNAA system has the best performance.

Repetitively pulsed capacitor bank for the dense-plasma focus

International Nuclear Information System (INIS)

Zucker, O.; Bostick, W.; Gullickson, R.; Long, J.; Luce, J.; Sahlin, H.

1975-12-01

This report describes a 1 pulse per second capacitor bank designed to energize a dense-plasma focus (DPF). The DPF is a neutron source capable (with moderate scaling) of delivering a minimum of 10 15 neutrons per pulse or neutron flux of 2 x 10 13 N/cm 2 .s. The average power consumption, which has become a major issue due to the energy crisis, is analyzed with respect to other plasma devices and is shown to be highly favorable. This small source size high flux neutron source could be extemely useful to qualify fission reactor material irradiation results for fusion reactor design

Repetitively pulsed capacitor bank for the dense-plasma focus

International Nuclear Information System (INIS)

Zucker, O.; Bostick, W.; Gullickson, R.; Long, J.; Luce, J.; Sahlin, H.

1976-01-01

This report describes a 1 pulse per second capacitor bank designed to energize a dense-plasma focus (DPF). The DPF is a neutron source capable (with moderate scaling) of delivering a minimum of 10 15 neutrons per pulse or neutron flux of 2 x 10 13 N/cm 2 . s. The average power consumption, which has become a major issue due to the energy crisis, is analyzed with respect to other plasma devices and is shown to be highly favorable. This small source size high flux neutron source could be extremely useful to qualify fission reactor material irradiation results for fusion reactor design

Neutron sources and its dosimetric characteristics

International Nuclear Information System (INIS)

Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M.; Mercado S, G.A.; Gallego D, E.; Lorente F, A.

2005-01-01

By means of Monte Carlo methods the spectra of the produced neutrons 252 Cf, 252 Cf/D 2 O, 241 Am Be, 239 Pu Be, 140 La Be, 239 Pu 18 O 2 and 226 Ra Be have been calculated. With the information of the spectrum it was calculated the average energy of the neutrons of each source. By means of the fluence coefficients to dose it was determined, for each one of the studied sources, the fluence factors to dose. The calculated doses were H, H * (10), H p,sIab (10, 0 0 ), E AP and E ISO . During the phase of the calculations the sources were modeled as punctual and their characteristics were determined to 100 cm in the hole. Also, for the case of the sources of 239 Pu Be and 241 Am Be, were carried out calculations modeling the sources with their respective characteristics and the dosimetric properties were determined in a space full with air. The results of this last phase of the calculations were compared with the experimental results obtained for both sources. (Author)

Non-destructive diagnostics of irradiated materials using neutron scattering from pulsed neutron sources

Energy Technology Data Exchange (ETDEWEB)

Korenev, Sergey E-mail: sergey_korenev@steris.com; Sikolenko, Vadim

2004-10-01

The advantage of neutron-scattering studies as compared to the standard X-ray technique is the high penetration of neutrons that allow us to study volume effects. The high resolution of instrumentation on the basis neutron scattering allows measurement of the parameters of lattice structure with high precision. We suggest the use of neutron scattering from pulsed neutron sources for analysis of materials irradiated with pulsed high current electron and ion beams. The results of preliminary tests using this method for Ni foils that have been studied by neutron diffraction at the IBR-2 (Pulsed Fast Reactor at Joint Institute for Nuclear Research) are presented.

Non-destructive diagnostics of irradiated materials using neutron scattering from pulsed neutron sources

Science.gov (United States)

Korenev, Sergey; Sikolenko, Vadim

2004-09-01

The advantage of neutron-scattering studies as compared to the standard X-ray technique is the high penetration of neutrons that allow us to study volume effects. The high resolution of instrumentation on the basis neutron scattering allows measurement of the parameters of lattice structure with high precision. We suggest the use of neutron scattering from pulsed neutron sources for analysis of materials irradiated with pulsed high current electron and ion beams. The results of preliminary tests using this method for Ni foils that have been studied by neutron diffraction at the IBR-2 (Pulsed Fast Reactor at Joint Institute for Nuclear Research) are presented.

Optimized sub thermal neutron source to Linac of CAB

International Nuclear Information System (INIS)

Torres, L; Granada, R

2006-01-01

We present the results of calculations performed with the code M C N P relative to the neutron field behavior within the moderator for the Bariloche-Linac cold neutron source, using polyethylene as pre moderator and solid mesitylene as moderating material at 90 K.The optimum dimensions for a moderator were obtained, with and without a pre moderator, from the point of view of neutron production and time-width of the neutron pulse.Finally, we adopted for our cold neutron source, a slab pre moderator of P L E at room temperature, and a cylindrical moderator of mesitylene at 90 K with a cooler system of stainless steel with windows of Zircaloy-4 [es

Characteristics of the WNR: a pulsed spallation neutron source

International Nuclear Information System (INIS)

Russell, G.J.; Lisowski, P.W.; Howe, S.D.; King, N.S.P.; Meier, M.M.

1982-01-01

The Weapons Neutron Research facility (WNR) is a pulsed spallation neutron source in operation at the Los Alamos National Laboratory. The WNR uses part of the 800-MeV proton beam from the Clinton P. Anderson Meson Physics Facility accelerator. By choosing different target and moderator configurations and varying the proton pulse structure, the WNR can provide a white neutron source spanning the energy range from a few MeV to 800 MeV. The neutron spectrum from a bare target has been measured and is compared with predictions using an Intranuclear Cascade model coupled to a Monte Carlo transport code. Calculations and measurements of the neutronics of WNR target-moderator assemblies are presented

Development of high intensity ion sources for a Tandem-Electrostatic-Quadrupole facility for Accelerator-Based Boron Neutron Capture Therapy

International Nuclear Information System (INIS)

Bergueiro, J.; Igarzabal, M.; Suarez Sandin, J.C.; Somacal, H.R.; Thatar Vento, V.; Huck, H.; Valda, A.A.; Repetto, M.

2011-01-01

Several ion sources have been developed and an ion source test stand has been mounted for the first stage of a Tandem-Electrostatic-Quadrupole facility For Accelerator-Based Boron Neutron Capture Therapy. A first source, designed, fabricated and tested is a dual chamber, filament driven and magnetically compressed volume plasma proton ion source. A 4 mA beam has been accelerated and transported into the suppressed Faraday cup. Extensive simulations of the sources have been performed using both 2D and 3D self-consistent codes.

Development of high intensity ion sources for a Tandem-Electrostatic-Quadrupole facility for Accelerator-Based Boron Neutron Capture Therapy

Energy Technology Data Exchange (ETDEWEB)

Bergueiro, J. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina)] [CONICET, Buenos Aires (Argentina); Igarzabal, M.; Suarez Sandin, J.C. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina); Somacal, H.R. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina)] [Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin (Argentina); Thatar Vento, V. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina)] [CONICET, Buenos Aires (Argentina); Huck, H.; Valda, A.A. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina)] [Escuela de Ciencia y Tecnologia, Universidad Nacional de San Martin (Argentina); Repetto, M. [Gerencia de Investigacion y Aplicaciones, Comision Nacional de Energia Atomica (Argentina)

2011-12-15

Several ion sources have been developed and an ion source test stand has been mounted for the first stage of a Tandem-Electrostatic-Quadrupole facility For Accelerator-Based Boron Neutron Capture Therapy. A first source, designed, fabricated and tested is a dual chamber, filament driven and magnetically compressed volume plasma proton ion source. A 4 mA beam has been accelerated and transported into the suppressed Faraday cup. Extensive simulations of the sources have been performed using both 2D and 3D self-consistent codes.

The new high flux neutron source FRM-2 in Munich

International Nuclear Information System (INIS)

Roegler, H.J.; Wierheim, G.

2002-01-01

Quite some years ago in 1974 to be exact, the first consideration on a new neutron source started at the technical university of Munich (Germany). 27 years later the new high flux neutron source (FRM-2) was read for hot operation, now delayed by a refused approval for its third partial license by the federal government of Germany despite a wide support from the scientific community. FRM-2 is a tank-type research reactor cooled by water, moderated by heavy water and whose thermal power was limited to 20 MW maximum. The extreme compact core together with the applied inverse flux principle led to a neutron flux design value of 8.10 18 n/m 2 .s at the reflector peak. 10 beam tubes will allow an optimized use of the high neutron flux. A hot neutron source with graphite at about 2200 Celsius degrees and a cold neutron source with liquid D 2 at about 25 K will provide shifted energy spectra. The utilization of FRM-2 is many-fold: neutronography and tomography, medical irradiation, radio-nuclide production, doping of pure silicon, neutron activation analysis. (A.C.)

Detection of fission signatures induced by a low-energy neutron source

International Nuclear Information System (INIS)

Ocherashvili, A.; Becka, A.; Mayorovb, V.; Roesgen, E.; Crochemoreb, J.-M.; Mosconi, M.; Pedersen, B.; Heger, C.

2015-01-01

We present a method for the detection of special nuclear materials (SNM) in shielded containers which is both sensitive and applicable under field conditions. The method uses an external pulsed neutron source to induce fission in SNM and subsequent detection of the fast prompt fission neutrons. The detectors surrounding the container under investigation are liquid scintillation detectors able to distinguish gamma rays from fast neutrons by means of the pulse shape discrimination method (PSD). One advantage of these detectors, besides the ability for PSD analysis, is that the analogue signal from a detection event is of very short duration (typically few tens of nanoseconds). This allows the use of very short coincidence gates for the detection of the prompt fission neutrons in multiple detectors while benefiting from a low accidental (background) coincidence rate yielding a low detection limit. Another principle advantage of this method derives from the fact that the external neutron source is pulsed. By proper time gating the interrogation can be conducted by epithermal and thermal source neutrons only. These source neutrons do not appear in the fast neutron signal following the PSD analysis thus providing a fundamental method for separating the interrogating source neutrons from the sample response in form of fast fission neutrons. The paper describes laboratory tests with a configuration of eight detectors in the Pulsed Neutron Interrogation Test Assembly (PUNITA). The sensitivity of the coincidence signal to fissile mass is investigated for different sample configurations and interrogation regimes.

Time-correlated neutron analysis of a multiplying HEU source

Energy Technology Data Exchange (ETDEWEB)

Miller, E.C., E-mail: Eric.Miller@jhuapl.edu [Johns Hopkins University Applied Physics Laboratory, Laurel, MD (United States); Kalter, J.M.; Lavelle, C.M. [Johns Hopkins University Applied Physics Laboratory, Laurel, MD (United States); Watson, S.M.; Kinlaw, M.T.; Chichester, D.L. [Idaho National Laboratory, Idaho Falls, ID (United States); Noonan, W.A. [Johns Hopkins University Applied Physics Laboratory, Laurel, MD (United States)

2015-06-01

The ability to quickly identify and characterize special nuclear material remains a national security challenge. In counter-proliferation applications, identifying the neutron multiplication of a sample can be a good indication of the level of threat. Currently neutron multiplicity measurements are performed with moderated {sup 3}He proportional counters. These systems rely on the detection of thermalized neutrons, a process which obscures both energy and time information from the source. Fast neutron detectors, such as liquid scintillators, have the ability to detect events on nanosecond time scales, providing more information on the temporal structure of the arriving signal, and provide an alternative method for extracting information from the source. To explore this possibility, a series of measurements were performed on the Idaho National Laboratory's MARVEL assembly, a configurable HEU source. The source assembly was measured in a variety of different HEU configurations and with different reflectors, covering a range of neutron multiplications from 2 to 8. The data was collected with liquid scintillator detectors and digitized for offline analysis. A gap based approach for identifying the bursts of detected neutrons associated with the same fission chain was used. Using this approach, we are able to study various statistical properties of individual fission chains. One of these properties is the distribution of neutron arrival times within a given burst. We have observed two interesting empirical trends. First, this distribution exhibits a weak, but definite, dependence on source multiplication. Second, there are distinctive differences in the distribution depending on the presence and type of reflector. Both of these phenomena might prove to be useful when assessing an unknown source. The physical origins of these phenomena can be illuminated with help of MCNPX-PoliMi simulations.

Time-correlated neutron analysis of a multiplying HEU source

Science.gov (United States)

Miller, E. C.; Kalter, J. M.; Lavelle, C. M.; Watson, S. M.; Kinlaw, M. T.; Chichester, D. L.; Noonan, W. A.

2015-06-01

The ability to quickly identify and characterize special nuclear material remains a national security challenge. In counter-proliferation applications, identifying the neutron multiplication of a sample can be a good indication of the level of threat. Currently neutron multiplicity measurements are performed with moderated 3He proportional counters. These systems rely on the detection of thermalized neutrons, a process which obscures both energy and time information from the source. Fast neutron detectors, such as liquid scintillators, have the ability to detect events on nanosecond time scales, providing more information on the temporal structure of the arriving signal, and provide an alternative method for extracting information from the source. To explore this possibility, a series of measurements were performed on the Idaho National Laboratory's MARVEL assembly, a configurable HEU source. The source assembly was measured in a variety of different HEU configurations and with different reflectors, covering a range of neutron multiplications from 2 to 8. The data was collected with liquid scintillator detectors and digitized for offline analysis. A gap based approach for identifying the bursts of detected neutrons associated with the same fission chain was used. Using this approach, we are able to study various statistical properties of individual fission chains. One of these properties is the distribution of neutron arrival times within a given burst. We have observed two interesting empirical trends. First, this distribution exhibits a weak, but definite, dependence on source multiplication. Second, there are distinctive differences in the distribution depending on the presence and type of reflector. Both of these phenomena might prove to be useful when assessing an unknown source. The physical origins of these phenomena can be illuminated with help of MCNPX-PoliMi simulations.

Time-correlated neutron analysis of a multiplying HEU source

International Nuclear Information System (INIS)

Miller, E.C.; Kalter, J.M.; Lavelle, C.M.; Watson, S.M.; Kinlaw, M.T.; Chichester, D.L.; Noonan, W.A.

2015-01-01

The ability to quickly identify and characterize special nuclear material remains a national security challenge. In counter-proliferation applications, identifying the neutron multiplication of a sample can be a good indication of the level of threat. Currently neutron multiplicity measurements are performed with moderated 3 He proportional counters. These systems rely on the detection of thermalized neutrons, a process which obscures both energy and time information from the source. Fast neutron detectors, such as liquid scintillators, have the ability to detect events on nanosecond time scales, providing more information on the temporal structure of the arriving signal, and provide an alternative method for extracting information from the source. To explore this possibility, a series of measurements were performed on the Idaho National Laboratory's MARVEL assembly, a configurable HEU source. The source assembly was measured in a variety of different HEU configurations and with different reflectors, covering a range of neutron multiplications from 2 to 8. The data was collected with liquid scintillator detectors and digitized for offline analysis. A gap based approach for identifying the bursts of detected neutrons associated with the same fission chain was used. Using this approach, we are able to study various statistical properties of individual fission chains. One of these properties is the distribution of neutron arrival times within a given burst. We have observed two interesting empirical trends. First, this distribution exhibits a weak, but definite, dependence on source multiplication. Second, there are distinctive differences in the distribution depending on the presence and type of reflector. Both of these phenomena might prove to be useful when assessing an unknown source. The physical origins of these phenomena can be illuminated with help of MCNPX-PoliMi simulations

Proceedings of the fifteenth meeting of the international collaboration on advanced neutron sources (ICANS-XV). Advanced neutron sources towards the next century

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Jun-ichi [Center for Neutron Science, Tokai Research Establishment, Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan); Itoh, Shinichi [Neutron Science Laboratory, High Energy Accelerator Research Organization, Tsukuba, Ibaraki (JP)

2001-03-01

The fifteenth meeting of the International Collaboration on Advanced Neutron Sources (ICANS-XV) was held at Epocal Tsukuba, International Congress Center on 6-9 November 2000. It was hosted by Japan Atomic Energy Research Institute (JAERI) and High Energy Accelerator Research Organization (KEK). This meeting focused on 'Neutron Sources toward the 21st Century' and research activities related to targets and moderators, neutron scattering instruments and accelerators were presented. The 151 of the presented papers are indexed individually. (J.P.N.)

Proceedings of the fifteenth meeting of the international collaboration on advanced neutron sources (ICANS-XV). Advanced neutron sources towards the next century

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Jun-ichi [Center for Neutron Science, Tokai Research Establishment, Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan); Itoh, Shinichi [Neutron Science Laboratory, High Energy Accelerator Research Organization, Tsukuba, Ibaraki (JP)] (eds.)

2001-03-01

The fifteenth meeting of the International Collaboration on Advanced Neutron Sources (ICANS-XV) was held at Epocal Tsukuba, International Congress Center on 6-9 November 2000. It was hosted by Japan Atomic Energy Research Institute (JAERI) and High Energy Accelerator Research Organization (KEK). This meeting focused on 'Neutron Sources toward the 21st Century' and research activities related to targets and moderators, neutron scattering instruments and accelerators were presented. The 151 of the presented papers are indexed individually. (J.P.N.)

Characterization of the radiation background at the Spallation Neutron Source

International Nuclear Information System (INIS)

DiJulio, Douglas D.; Cherkashyna, Nataliia; Scherzinger, Julius; Khaplanov, Anton; Pfeiffer, Dorothea; Cooper-Jensen, Carsten P.; Fissum, Kevin G.; Kanaki, Kalliopi; Kirstein, Oliver; Hall-Wilton, Richard J.; Bentley, Phillip M.; Ehlers, Georg; Gallmeier, Franz X.; Hornbach, Donald E.; Iverson, Erik B.; Newby, Robert J.

2016-01-01

We present a survey of the radiation background at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, TN, USA during routine daily operation. A broad range of detectors was used to characterize primarily the neutron and photon fields throughout the facility. These include a WENDI-2 extended range dosimeter, a thermoscientific NRD, an Arktis 4 He detector, and a standard NaI photon detector. The information gathered from the detectors was used to map out the neutron dose rates throughout the facility and also the neutron dose rate and flux profiles of several different beamlines. The survey provides detailed information useful for developing future shielding concepts at spallation neutron sources, such as the European Spallation Source (ESS), currently under construction in Lund, Sweden. (paper)

Characterization of a deuterium-deuterium plasma fusion neutron generator

Science.gov (United States)

Lang, R. F.; Pienaar, J.; Hogenbirk, E.; Masson, D.; Nolte, R.; Zimbal, A.; Röttger, S.; Benabderrahmane, M. L.; Bruno, G.

2018-01-01

We characterize the neutron output of a deuterium-deuterium plasma fusion neutron generator, model 35-DD-W-S, manufactured by NSD/Gradel-Fusion. The measured energy spectrum is found to be dominated by neutron peaks at 2.2 MeV and 2.7 MeV. A detailed GEANT4 simulation accurately reproduces the measured energy spectrum and confirms our understanding of the fusion process in this generator. Additionally, a contribution of 14 . 1 MeV neutrons from deuterium-tritium fusion is found at a level of 3 . 5%, from tritium produced in previous deuterium-deuterium reactions. We have measured both the absolute neutron flux as well as its relative variation on the operational parameters of the generator. We find the flux to be proportional to voltage V 3 . 32 ± 0 . 14 and current I 0 . 97 ± 0 . 01. Further, we have measured the angular dependence of the neutron emission with respect to the polar angle. We conclude that it is well described by isotropic production of neutrons within the cathode field cage.