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Sample records for fast neutrons raschet

  1. Fast neutrons dosimetry

    International Nuclear Information System (INIS)

    Rzyski, B.M.

    1977-01-01

    A proton recoil technique has been developed for inducing thermoluminescence with incident fast neutrons. CaF 2 was used as the TL phosphor, and cane sugar and polyethylene were used as proton radiators. The phosphor and the hydrogeneous material powders were well mixed, encapsulated in glass tubes and exposed to Am-Be sources, resulting in recoils from incident fast neutrons of energy between 0,25 and 11,25 MeV. The intrinsic response of pure CaF 2 to fast neutrons without a hydrogeneous radiator was checked by using LiF (TLD-700). Glow curves were recorded from room temperature up to 350 0 C after different doses of neutrons and gamma rays of 60 Co. First collision dose due to fast neutrons in tissue like materials such as cane sugar and polyethylene was also calculated [pt

  2. Fast neutron dosimetry

    International Nuclear Information System (INIS)

    DeLuca, P.M. Jr.; Pearson, D.W.

    1993-01-01

    Research concentrated on three major areas during the last twelve months: (1) investigations of energy fluence and absorbed dose measurements using crystalline and hot pressed TLD materials exposes to ultrasoft beams of photons, (2) fast neutron kerma factor measurements for several important elements as well as NE-213 scintillation material response function determinations at the intense ''white'' source available at the WNR facility at LAMPF, and (3) kerma factor ratio determinations for carbon and oxygen to A-150 tissue equivalent plastic at the clinical fast neutron radiation facility at Harper Hospital, Detroit, MI. Progress summary reports of these efforts are given in this report

  3. Simplified fast neutron dosimeter

    International Nuclear Information System (INIS)

    Sohrabi, M.

    1979-01-01

    Direct fast-neutron-induced recoil and alpha particle tracks in polycarbonate films may be enlarged for direct visual observation and automated counting procedures employing electrochemical etching techniques. Electrochemical etching is, for example, carried out in a 28% KOH solution at room temperature by applying a 2000 V peak-to-peak voltage at 1 kHz frequency. Such recoil particle amplification can be used for the detection of wide neutron dose ranges from 1 mrad to 1000 rads or higher, if desired. 5 claims

  4. Fast neutron dosimetry

    International Nuclear Information System (INIS)

    DeLuca, P.M. Jr.; Pearson, D.W.

    1992-01-01

    This progress report concentrates on two major areas of dosimetry research: measurement of fast neutron kerma factors for several elements for monochromatic and white spectrum neutron fields and determination of the response of thermoluminescent phosphors to various ultra-soft X-ray energies and beta-rays. Dr. Zhixin Zhou from the Shanghai Institute of Radiation Medicine, People's Republic of China brought with him special expertise in the fabrication and use of ultra-thin TLD materials. Such materials are not available in the USA. The rather unique properties of these materials were investigated during this grant period

  5. FAST NEUTRON SPECTROMETER

    Science.gov (United States)

    Davis, F.J.; Hurst, G.S.; Reinhardt, P.W.

    1959-08-18

    An improved proton recoil spectrometer for determining the energy spectrum of a fast neutron beam is described. Instead of discriminating against and thereby"throwing away" the many recoil protons other than those traveling parallel to the neutron beam axis as do conventional spectrometers, this device utilizes protons scattered over a very wide solid angle. An ovoidal gas-filled recoil chamber is coated on the inside with a scintillator. The ovoidal shape of the sensitive portion of the wall defining the chamber conforms to the envelope of the range of the proton recoils from the radiator disposed within the chamber. A photomultiplier monitors the output of the scintillator, and a counter counts the pulses caused by protons of energy just sufficient to reach the scintillator.

  6. Fast-neutron reactor

    International Nuclear Information System (INIS)

    Iljunin, V.G.; Murogov, V.M.; Shmelev, A.N.

    1974-01-01

    A description is given of a fast-neutron reactor wherein the core and the surrounding lateral and axial blankets are made up of fuel element stacks. The walls of each stack have holes in the middle portion thereof with respect to the height of the core. Main and additional fuel elements are arranged respectively above and below the plane passing through the centers ofthe holes, inside each stack, the spacing between which fuel elements form, together with the holes, the inlet header of the coolant washing the fuel elements. The inlet header splits the coolant into two oppositely directed flows lead away by two outlet headers arranged above and below the upper and lower axial blankets

  7. Artefacts of fast neutron radiography concerned with neutron scattering

    International Nuclear Information System (INIS)

    Mikerov, V.I.; Isakov, A.I.; Tukarev, V.A.; Koshelev, A.P.; Bykov, A.A.; Khodeev, A.I.; Waschkowski, W.

    1999-01-01

    The paper considers peculiarities of fast neutron radiography with a two dimensional detector. Effects produced by scattered neutrons was simulated for various neutron sources. Contribution of γ-rays generated in the sample was estimated for a fission spectrum of fast neutrons. Feasibility of fast neutrons collimating by a honeycomb collimator was considered.(author)

  8. Fast neutron spectrometry and dosimetry

    International Nuclear Information System (INIS)

    Blaize, S.; Ailloud, J.; Mariani, J.; Millot, J.P.

    1958-01-01

    We have studied fast neutron spectrometry and dosimetry through the recoil protons they produce in hydrogenated samples. In spectrometric, we used nuclear emulsions, in dosimetric, we used polyethylene coated with zinc sulphide and placed before a photomultiplier. (author) [fr

  9. Fast neutron imaging device and method

    Science.gov (United States)

    Popov, Vladimir; Degtiarenko, Pavel; Musatov, Igor V.

    2014-02-11

    A fast neutron imaging apparatus and method of constructing fast neutron radiography images, the apparatus including a neutron source and a detector that provides event-by-event acquisition of position and energy deposition, and optionally timing and pulse shape for each individual neutron event detected by the detector. The method for constructing fast neutron radiography images utilizes the apparatus of the invention.

  10. Computerized tomography using fast neutrons

    International Nuclear Information System (INIS)

    Maier-Schuler, P.

    1992-03-01

    The equipment is transportable and can be used at different neutron sources. CT-images are presented showing that it is possible to get good results by using CT with fast neutrons in non destructive testing. Small defects with high contrasts can be detected as well as larger defects with small differences in material density. Since the neutrons interact with the nuclei and not with the electron density the CT-images contain different information compared with X-ray or γ images. As neutron sources always emit γ-radiation too, this radiation can be detected simultaneously with the neutrons. Therefore one can get a γ CT-image along with the neutron image. For the examination of small samples or objects containing materials with great differences in the linear attenuation coefficients like Al and H 2 thermal neutrons have been used for CT-measurements too. A spatial resolution and a density resolution of 0.1 mm and about 5% respectively could be achieved in the CT-images with fast neutrons and 0.04 mm with thermal neutrons. (orig./HP) [de

  11. Biological effectiveness of fast neutrons

    International Nuclear Information System (INIS)

    Coppola, M.; Silini, G.

    1980-01-01

    It has been found experimentally that fast neutron RBE values generally increase with decreasing neutron doses. This finding reflects the existence of a difference in the shape between the functional dependences of the effect on dose produced by neutrons and by the reference radiation. The most common interpretation of this difference assumes a linear dose-effect relationship for neutrons and a linear plus quadratic relationship for X - or gamma-rays. In radiation protection the assumption of linearity is taken to be valid throughout the whole dose region of interest and is essential for the validity of the extrapolation to low doses of the risk estimates obtained at higher dose levels. On the other hand, the same trend of the RBE versus neutron dose would still be observed, if the biological effect induced by neutrons would be less than proportional to the dose. However, in this latter case the risks of neutron irradiation estimated from data at higher doses would no longer be safely utilized at lower dose levels. The results of various experiments with fast neutrons on different biological systems are examined in an attempt to throw some light on this aspect of radiation protection. It appears that in some cases linear non-threshold dose-effect relationships may not fit experimental series obtained with neutrons at relatively low doses. (H.K.)

  12. Fast neutron dosimetry

    International Nuclear Information System (INIS)

    DeLuca, P.M. Jr.; Pearson, D.W.

    1991-01-01

    During 1988--1990 the magnetic resonance dosimetry project was completed, as were the 250 MeV proton shielding measurements. The first cellular experiment using human cells in vitro at the 1 GeV electron storage ring was also accomplished. More detail may be found in DOE Report number-sign DOE/EV/60417-002 and the open literature cited in the individual progress subsections. We report Kinetic Energy Released in Matter (KERMA), factor measurements in several elements of critical importance to neutron radiation therapy and radiation protection for space habitation and exploration for neutron energies below 30 MeV. The results of this effort provide the only direct measurements of the oxygen and magnesium kerma factors above 20 MeV neutron energy, and the only measurements of the iron kerma factor above 15 MeV. They provide data of immediate relevance to neutron radiotherapy and impose strict criteria for normalizing and testing nuclear models used to calculate kerma factors at higher neutron energies

  13. Medical radiography with fast neutrons

    International Nuclear Information System (INIS)

    Duehmke, E.

    1980-01-01

    Neutron radiography is important in medicine for two reasons. On the one hand, macroradiographical findings are different from X-ray findings, i.e. new information may be gained on the morphology of humans and animals. On the other hand, there is a direct practical application in the radiotherapy of malignant tumours if one considers the assessment of the growth of malignant processes. Fast neutrons are required for neutron radiographies of biological objects with a diameter of more than 2 cm. In addition sensitive, two-dimensional detectors must be used which are selective for fast neutrons. The book describes the optimisation and sensitisation of a detector using the example of cellulose nitrate foil for fast reactor neutrons. Images of human spinal chords with tumours proved by pathological and anatomical examinations give a better picture of the dimensions of the tumour than comparative X-ray pictures. For examinations of living patients, neutron radiography should be applied only in those tumour-bearing parts of the bodies in which radiation treatment is required for therapeutical purposes anyway. (orig./MG) [de

  14. Fast neutron environments.

    Energy Technology Data Exchange (ETDEWEB)

    Buchheit, Thomas Edward; Kotula, Paul Gabriel; Lu, Ping; Brewer, Luke N. (Naval Postgraduate School, Monterey, CA); Goods, Steven Howard (Sandia National Laboratories, Livermore, CA); Foiles, Stephen Martin; Puskar, Joseph David; Hattar, Khalid Mikhiel; Doyle, Barney Lee; Boyce, Brad Lee; Clark, Blythe G.

    2011-10-01

    The goal of this LDRD project is to develop a rapid first-order experimental procedure for the testing of advanced cladding materials that may be considered for generation IV nuclear reactors. In order to investigate this, a technique was developed to expose the coupons of potential materials to high displacement damage at elevated temperatures to simulate the neutron environment expected in Generation IV reactors. This was completed through a high temperature high-energy heavy-ion implantation. The mechanical properties of the ion irradiated region were tested by either micropillar compression or nanoindentation to determine the local properties, as a function of the implantation dose and exposure temperature. In order to directly compare the microstructural evolution and property degradation from the accelerated testing and classical neutron testing, 316L, 409, and 420 stainless steels were tested. In addition, two sets of diffusion couples from 316L and HT9 stainless steels with various refractory metals. This study has shown that if the ion irradiation size scale is taken into consideration when developing and analyzing the mechanical property data, significant insight into the structural properties of the potential cladding materials can be gained in about a week.

  15. [Fast neutron cross section measurements

    International Nuclear Information System (INIS)

    Knoll, G.F.

    1992-01-01

    From its inception, the Nuclear Data Project at the University of Michigan has concentrated on two major objectives: (1) to carry out carefully controlled nuclear measurements of the highest possible reliability in support of the national nuclear data program, and (2) to provide an educational opportunity for students with interests in experimental nuclear science. The project has undergone a successful transition from a primary dependence on our photoneutron laboratory to one in which our current research is entirely based on a unique pulsed 14 MeV fast neutron facility. The new experimental facility is unique in its ability to provide nanosecond bursts of 14 MeV neutrons under conditions that are ''clean'' and as scatter-free as possible, and is the only one of its type currently in operation in the United States. It has been designed and put into operation primarily by graduate students, and has met or exceeded all of its important initial performance goals. We have reached the point of its routine operation, and most of the data are now in hand that will serve as the basis for the first two doctoral dissertations to be written by participating graduate students. Our initial results on double differential neutron cross sections will be presented at the May 1993 Fusion Reactor Technology Workshop. We are pleased to report that, after investing several years in equipment assembly and optimization, the project has now entered its ''data production'' phase

  16. General remarks on fast neutron reactor physics

    International Nuclear Information System (INIS)

    Barre, J.Y.

    1980-01-01

    The main aspects of fast reactor physics, presented in these lecture notes, are restricted to LMFBR's. The emphasis is placed on the core neutronic balance and the burn-up problems. After a brief description of the power reactor main components and of the fast reactor chronology, the fundamental parameters of the one-group neutronic balance are briefly reviewed. Then the neutronic burn-up problems related to the Pu production and to the doubling time are considered

  17. Neutron source for generating fast neutrons

    International Nuclear Information System (INIS)

    Schraube, H.; Morhart, A.

    1980-01-01

    In radiotherapeutics, neutron sources are needed, generating a dose rate as high as possible and neutrons as energetic as possible. By bombardment of tritium targets with deuterons of some 100 keV, neutrons of about 15 MeV are produced, but because of the large slow-down effect in the target consisting of heavy metal the yield is too small. On applying beryllium targets the neutron yields are too small below a deuteron energy of 15 MeV; at the same time, the high percentage of low energy neutrons is undesirable. Based on the favorable yield of the D(d,n) He 3 reaction for deuterons of about 100 MeV, a gas-target chamber is designed. The pressure chamber is designed for a deuterium pressure of up to 11 atmospheres and provided with cooling devices. The flux density in beam direction at a distance of 1 m reaches 108 per cm 2 , the maximum energy of the neutrons amounts to 12 MeV at deuteron energies of 9 MeV, and the neutron share below 9 MeV is small. The maximum dose rate in a tissue-equivalent phantom lies at 40 rads/min. (orig./PW)

  18. Fast neutron radiography in biology and medicine

    International Nuclear Information System (INIS)

    Duehmke, E.; Greim, L.

    1983-01-01

    Fast neutrons are necessary for neutron radiography of extended biological objects. Applying cellulose nitrate foils to assure specific neutrograms undisturbed by X- and γ-ray effects, a multifoil stack can be used as detector in order to improve image quality and to reduce neutron dose down to less than 10 rem. Neutron radiography enables to observe the exsiccation process in biological materials, e.g. wood, which could not be achieved by X-ray radiography. In medicine neutron radiography could be of value for detecting pathological changes within bone such as replacement of bone marrow by fat or tumor, as shown in human vertebral columns. (Auth.)

  19. Fast neutron radiography using photoluminescent imaging plates

    International Nuclear Information System (INIS)

    Rant, J.; Kristof, E.; Balasko, M.; Stade, J.

    1999-01-01

    Fast neutron radiography (FNR) and resonance neutron radiography (RNR) are complementary to the conventional radiography with high energy gamma-rays or brems-strahlung radiation used for the inspection of thick metal objects. In both non-destructive methods, the contrast sensitivity and the penetration power can be improved by using higher energy neutrons. At present direct techniques based either n Solid State Nuclear Track detectors (SSNTDs) or scintillating screens and transfer techniques using activation threshold detectors and radiographic films are applied for the detection of fast neutron images. Rather low detection sensitivity of film and SSNTD based fast neutron imaging methods and also rather poor inherent image contrast of SSNTD pose a problem for FNR in the fast neutron energy region 1-15 MeV interesting for NDT. For more efficient detection of fast neutron images the use of novel highly sensitive photoluminescent imaging plates (IP) in combination with threshold at the KFKI research reactor. The conventional IP produced by FUJI Photo Film Co. for the detection of beta and X-ray radiation were used. The threshold activation detectors were the reactions 115 In(n, n') 115m In, 64 Zn(n,p) 64 Cu, 56 Fe(n, p) 56 Mn, 24 Mg(n, p) 24 Na and 27 Al(n, α) 24 Na. These threshold reactions cover the fast neutron energy region between 0,7 MeV and 12 MeV. Pure, commercially available metals 0,1 mm to 0,25 mm thick made of In, Zn, Fe, Mg and Al were used as converter screens. The very high sensitivity of IP, the linearity of their response over 5 decades of exposure dose and the high dynamic digitalisation latitude enabled fast neutron radiography of image quality comparable to the quality of thermal NR. In our experimental conditions (φ n ∼ 10 8 n/cm 2 s, R Cd ∼ 2) the neutron exposure and IP exposure periods were still practical and comparable to the half life of the corresponding reaction products (half an hour to several hours). Even with the 27 Al(n.α) 24

  20. Some neutronics of innovative subcritical assembly with fast neutron spectrum

    International Nuclear Information System (INIS)

    Kiyavitskaya, H.; Fokov, Yu.; Rutkovskaya, Ch.; Sadovich, S.; Kasuk, D.; Gohar, Y.; Bolshinsky, I.

    2013-01-01

    Conclusion: • New assembly can be used to: • develop the experimental techniques and adapt the existing ones for monitoring the sub-criticality level, neutron spectra measurements, etc; • study the spatial kinetics of sub-critical and critical systems with fast neutron spectra; • measure the transmutation reaction rates of minor-actinides etc

  1. Clinical application of fast neutrons

    International Nuclear Information System (INIS)

    Battermann, J.J.

    1981-01-01

    The results of treatments and clinical experiments with neutrons (from a medical d+T neutron generator with an output of 10 12 neutrons per second) are reported and discussed. Data on RBE values are presented after single doses and multiple fractions of neutrons and 60 Co-gamma rays on pulmonary metastases. The results of pilot studies on head and neck tumours, brain tumours and pelvic tumours are discussed. The accuracy of the calculated dose is tested with some in-vivo experiments during neutron irradiation of the pelvis. Estimations of RBE values for tumour control, skin damage and intestinal damage after fractionated neutron therapy are dealt with and the results obtained in treatment of sarcomas are discussed. The preliminary results are given of some clinical trials in Amsterdam. Also some data from other centres are reviewed. From these data some remarks about the future of neutron therapy are made. (Auth.)

  2. Electrical resistivity of fast neutron irradiated bismuth

    International Nuclear Information System (INIS)

    Quelard, G.

    1975-01-01

    The production and recovery of fast neutron radiation damage in bismuth, at 20K has been studied by means of electrical resistivity. Results are independent of crystallographic orientation and indicate a creation of carriers during irradiation [fr

  3. Fast-neutron interaction with niobium

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.B.; Guenther, P.T.; Poenitz, W.P.; Smith, D.L.; Whalen, J.F.; Howerton, R.J.

    1985-01-01

    Results of a comprehensive study of the interaction of fast neutrons with niobium are presented, including measurement and interpretation of neutron total, differential-scattering and radiative-capture cross sections. The experimental results are interpreted in the context of the optical-statistical model, with attention to the Fermi-surface anomaly. Experimental results, physical interpretations and rigorous statistical methods are used to provide a comprehensive evaluated nuclear data file suitable for use in a wide range of applied neutronic calculations.

  4. Development of fast neutron profiling method

    CERN Document Server

    Miura, T; Sanami, T; Yamazaki, T; Ibaraki, M; Hirasawa, Y; Hiroishi, T; Aoki, T; Yamadera, A; Nakamura, T

    2002-01-01

    We discuss the effects of neutron scattering and gamma-ray background in fast neutron imaging and the method to reduce them. As a profiling device, a combination of an imaging plate (IP) and a polypropylene film (CH sub 2) has been employed in this study. Good profiles were obtained by employing appropriate neutron energy, a CH sub 2 thickness and geometry for accelerator-based fast neutrons (5-14 MeV). The neutron flux was approx 3.5x10 sup 4 cm sup - sup 2 s sup - sup 1 in the CH sub 2 -IP position. Furthermore, we are designing the device using a position-sensitive photomultiplier in order to improve the signal-to-noise ratio by obtaining the information of pulse height for particle selection together with position.

  5. A system for fast neutron radiography

    International Nuclear Information System (INIS)

    Klann, R.T.

    1996-01-01

    A system has been designed and a neutron generator installed to perform fast neutron radiography. With this sytem, objects as small as a coin or as large as a waste drum can be radiographed. The neutron source is an MF Physics A-711 neutron generator which produces 3x10 10 neutrons/second with an average energy of 14.5 MeV. The radiography system uses x-ray scintillation screens and film in commercially available cassettes. The cassettes have been modified to include a thin sheet of plastic to convert neutrons to protons through elastic scattering from hydrogen and other low Z materials in the plastic. For film densities from 1.8 to 3.0, exposures range from 1.9x10 7 to 3.8x10 8 n/cm 2 depending on the type of screen and film

  6. Detectors for Energy-Resolved Fast Neutron Imaging

    OpenAIRE

    Dangendorf, V.; Breskin, A.; Chechik, R.; Feldman, G.; Goldberg, M. B.; Jagutzki, O.; Kersten, C.; Laczko, G.; Mor, I.; Spillman, U.; Vartsky, D.

    2004-01-01

    Two detectors for energy-resolved fast-neutron imaging in pulsed broad-energy neutron beams are presented. The first one is a neutron-counting detector based on a solid neutron converter coupled to a gaseous electron multiplier (GEM). The second is an integrating imaging technique, based on a scintillator for neutron conversion and an optical imaging system with fast framing capability.

  7. Fast neutron damage in germanium detectors

    International Nuclear Information System (INIS)

    Kraner, H.W.

    1979-10-01

    The effects of fast neutron radiation damage on the performance of both Ge(Li) and Ge(HP) detectors have been studied during the past decade and will be summarized. A review of the interaction processes leading to the defect structures causing trapping will be made. The neutron energy dependence of observable damage effects will be considered in terms of interaction and defect production cross sections

  8. Fast neutron therapy in advanced malignant tumour treatment

    International Nuclear Information System (INIS)

    Avinc, A.

    1998-01-01

    In this report the fast neutron therapy applications were examined by thoroughly consideration of the fast neutron sources and the interactions of the fast neutron by the medium. The efficacy of fast neutron radiotherapy with that of patients with locally advanced tumours were compared. Radiological data indicate that fast neutrons could bring benefit in the treatment of some tumour types especially salivary glands, paranasal sinuses, soft tissue sarcomas, prostatic adenocarcinomas, palliative treatment of melanoma and rectum. There is a significant improvement in local/regional control for the neutron group, but no improvement in the survival. The neutron therapy is suggested through which this benefit could be achieved

  9. Measurement of fast neutron background in SAGE

    CERN Document Server

    Abdurashitov, J N; Kalikhov, A V; Matushko, V L; Shikhin, A A; Yants, V E; Zaborskaia, O S

    2002-01-01

    The spectrometer intended for direct measurements of ultra low fluxes of fast neutrons is described. It is sensitive to neutron fluxes of 10 sup - sup 7 cm sup - sup 2 s sup - sup 1 and lower. The detection efficiency of fast neutrons with simultaneous energy measurement was determined from Monte-Carlo simulation to be equal to 0.11 +- 0.01. The background counting rate in the detector corresponds to a neutron flux of (6.5 +- 2.1) x 10 sup - sup 7 cm sup - sup 2 s sup - sup 1 in the range 1.0-11.0 MeV. The natural neutron flux from the surrounding mine rock at the depth of 4700 meters of water equivalent was measured to be (7.3 +- 2.4) x 10 sup - sup 7 cm sup - sup 2 s sup - sup 1 in the range 1.0-11.0 MeV. The flux of fast neutrons in the SAGE main room was measured to be < 2.3 x 10 sup - sup 7 cm sup - sup 2 s sup - sup 1 in 1.0-11.0 MeV energy range.

  10. Investigation of the reflection of fast neutrons

    International Nuclear Information System (INIS)

    Devillers, Christian; Hasselin, Gilbert

    1964-10-01

    The authors report the study of the reflection of fast neutrons on a plane plate having a finite and varying thickness and an infinite width. Calculations are performed by using a Monte-Carlo method which allows the number, the energy, the direction, the emergence point of neutrons reflected on a plate, to be computed with respect to the energy and direction of incident neutrons. The author present how paths, elastic and inelastic shocks, direction after shock are calculated. Different information are calculated: the numbers of elastic shocks, inelastic shocks and transmitted neutrons, the number, energy and dose albedo, the spectrum and angular distribution, the distribution of neutron in terms of energy and direction

  11. Radiation therapy with fast neutrons: A review

    International Nuclear Information System (INIS)

    Jones, D.T.L.; Wambersie, A.

    2007-01-01

    Because of their biological effects fast neutrons are most effective in treating large, slow-growing tumours which are resistant to conventional X-radiation. Patients are treated typically 3-4 times per week for 4-5 weeks (sometimes in combination with X-radiation) for a variety of conditions such as carcinomas of the head and neck, salivary gland, paranasal sinus and breast; soft tissue, bone and uterine sarcomas and malignant melanomas. It is estimated that about 27,000 patients have undergone fast neutron therapy to date

  12. The Edinburgh experience of fast neutron therapy

    International Nuclear Information System (INIS)

    Duncan, W.; Arnott, S.J.; Orr, J.A.; Kerr, G.R.

    1982-01-01

    The Edinburgh experience is based on a d(15 + Be) neutron beam generated by a compact CS 30 Cyclotron. Neutron therapy alone given in 20 daily fractions over four weeks has been compared with photon therapy given in the same fractionation schedule. Since clinical studies began in March, 1977, over 500 patients have been treated by fast neutrons. Almost all patients are now admitted to randomly controlled trials. In the head and neck trial conducted in collaboration with collegues in Amsterdam and Essen, 192 patients are available for analysis. Most patients had T3 lesions and about 50% had involved nodes. The cumulative regression rate at six months is similar after neutrons and photons (75%). Later recurrence rates (36%) are also similar. The early radiation morbidity is similar in both groups, but the late reactions are greater after neutrons (15%) than photons (6%). Overall survival is better after photon therapy. A trial of patients with glioblastoma has also shown a better survival after photon therapy. Neutron therapy was associated with demyelinization in three of 18 patients. Patients with transitional cell cancer of the bladder have also been the subject of study. Local tumor control was similar (53%) after neutrons and photons. Late radiation morbidity was much greater after neutrons (20%), compared with photons (2%). In a trial of advanced carcinoma of the rectum, the local tumor control was also similar after neutrons and photons (30%), but morbidity was greater after neutrons. Soft tissue sarcomas have shown response rates (37%) that may be expected after photon therapy. Salivary gland tumors have shown a similar experience, although slow growing tumors such as adenoid cystic carcinoma may respond better to neutrons

  13. High spatial resolution fast-neutron imaging detectors for Pulsed Fast-Neutron Transmission Spectroscopy

    Science.gov (United States)

    Mor, I.; Vartsky, D.; Bar, D.; Feldman, G.; Goldberg, M. B.; Katz, D.; Sayag, E.; Shmueli, I.; Cohen, Y.; Tal, A.; Vagish, Z.; Bromberger, B.; Dangendorf, V.; Mugai, D.; Tittelmeier, K.; Weierganz, M.

    2009-05-01

    Two generations of a novel detector for high-resolution transmission imaging and spectrometry of fast-neutrons are presented. These devices are based on a hydrogenous fiber scintillator screen and single- or multiple-gated intensified camera systems (ICCD). This detector is designed for energy-selective neutron radiography with nanosecond-pulsed broad-energy (1-10 MeV) neutron beams. Utilizing the Time-of-Flight (TOF) method, such a detector is capable of simultaneously capturing several images, each at a different neutron energy (TOF). In addition, a gamma-ray image can also be simultaneously registered, allowing combined neutron/gamma inspection of objects. This permits combining the sensitivity of the fast-neutron resonance method to low-Z elements with that of gamma radiography to high-Z materials.

  14. Personal fast neutrons dosimetry using radiophotoluminescent glass

    International Nuclear Information System (INIS)

    Salem, Y. O.; Nachab, A.; Nourreddine, A.; Roy, C.

    2013-06-01

    In a previous paper we described a new ambient RPL dosimeter that detects fast neutrons in a mixed n-γ field via (n, p) reactions in a polyethylene converter. In the present study, a personal dosimeter is introduced to enable evaluating the individual dose equivalent H p (10) taking into account the albedo. A calibration factor for estimating H p (10) has been determined from the diminishing angular response as the angle of neutron incidence increases to 60 deg from the normal. MCNPX simulations for 241 Am-Be and 252 Cf neutrons, together with a series of monoenergetic neutron beams from 0.144 to 5 MeV, have been used to characterize the dosimeter response, which agrees well with the experimental 241 Am-Be response. (authors)

  15. The Edinburgh experience of fast neutron therapy

    International Nuclear Information System (INIS)

    Duncan, W.; Arnott, S.J.; Orr, J.A.; Kerr, G.R.

    1982-01-01

    The Edinburgh experience is based on a d(15 + Be) neutron beam generated by a compact CS 30 Cyclotron. The facility has an iso-center treatment head providing 240 0 of rotation. The most important limitation of the beam is its poor penetrating quality. We have compared neutron therapy alone given in 20 daily fractions over four weeks with photon therapy given in the same fractionation schedule. Since clinical studies began in March, 1977, over 500 patients have been treated by fast neutrons. Almost all patients are now admitted to randomly controlled trials. In the head and neck trial conducted in collaboraton with colleagues in Amsterdam and Essen, 92 patients are available for analysis. Most patients had T3 lesions and about 50% had involved nodes. The cumulative regression rate at six months is similar after neutrons and photons (75%). Later recurrence rates (36%) are also similar. The early radiation morbidity is similar in both groups, but the late reactions are greater after neutrons (15%) than photons (6%). Overall survival is better after photon therapy. A trial of patients with glioblastoma has also shown a better survival after photon therapy. Neutron therapy was associated with demelinization in three of 18 patients. Patients with transitional cell cancer of the bladder have also been the subject of study. Local tumor control was similar (53%) after neutrons and photons. Late radiation morbidity was much greater after neutrons (20%), compared with photons (2%). In a trial of advanced carcinoma of the rectum, the local tumor control was also similar after neutrons and photons (30%), but morbidity was greater after neutrons. Soft tissue sarcomas have shown response rates (37%) that may be expected after photon therapy

  16. Fast neutron dosimetry: Progress summary

    International Nuclear Information System (INIS)

    DeLuca, P.M. Jr.

    1988-01-01

    The purpose was to investigate the radiological physics and biology of very low energy photons derived from a 1-GeV electron synchrotron storage ring. An extensive beam line and irradiation apparatus was designed, developed, and constructed. Dosimetry measurements required invention and testing of a miniature absolute calorimeter and a cell irradiation fixture suitable for scanning exposures under computer control. Measurements of the kerma factors of oxygen, aluminum and silicon for 14-20 MeV neutrons. Custom designed miniature proportional counters of cylindrical symmetry were employed in these determinations. The oxygen kerma factor was found significantly lower than values calculated from microscopic cross sections. We also tested Mg and Fe walled conventional spherical counters. The direct neutron-counting gas interaction is significant enough for these counters that a correction is needed. We also investigated the application of Nuclear Magnetic Resonance spectroscopy to radiation dosimetry. Our purpose was to take advantage of recent development of very high-field magnets, complex RF-pulse techniques for solvent suppression, and improved spectral analysis techniques

  17. Fast neutron activation analysis by means of low voltage neutron generator

    Directory of Open Access Journals (Sweden)

    M.E. Medhat

    Full Text Available A description of D-T neutron generator (NG is presented. This machine can be used for fast neutron activation analysis applied to determine some selected elements, especially light elements, in different materials. Procedure of neutron flux determination and efficiency calculation is described. Examples of testing some Egyptian natural cosmetics are given. Keywords: Neutron generator, Fast neutron activation analysis, Elemental analysis

  18. Application of morphological filtration to fast neutron image denoising processing

    International Nuclear Information System (INIS)

    Zhang Faqiang; China Academy of Engineering Physics, Mianyang; Yang Jianlun; Li Zhenghong

    2006-01-01

    Fast neutron radiography system is mainly composed by a scintillation fiber array and a scientific grade optical CCD. Fast neutron images obtained by the system always suffer a serious noise disturbance. In order to weaken pepper and salt noise and Poisson noise, morphological filtration is applied to fast neutron image denoising processing. The results indicate that for fast neutron images, morphological filtration operations with two-dimensional multi-directional structure element are effective to filter the noise and hold image details. (authors)

  19. [Fast neutron cross section measurements

    International Nuclear Information System (INIS)

    1991-01-01

    In the 14 MeV Neutron Laboratory, we have continued the development of a facility that is now the only one of its kind in operation in the United States. We have refined the klystron bunching system described in last year's report to the point that 1.2 nanosecond pulses have been directly measured. We have tested the pulse shape discrimination capability of our primary NE 213 neutron detector. We have converted the RF sweeper section of the beamline to a frequency of 1 MHz to replace the function of the high voltage pulser described in last year's report which proved to be difficult to maintain and unreliable in its operation. We have also overcome several other significant experimental difficulties, including a major problem with a vacuum leak in the main accelerator column. We have completed additional testing to prove the remainder of the generation and measurement systems, but overcoming some of these experimental difficulties has delayed the start of actual data taking. We are now in a position to begin our first series of ring geometry elastic scattering measurements, and these will be underway before the end of the current contract year. As part of our longer term planning, we are continuing the conceptual analysis of several schemes to improve the intensity of our current pulsed beam. These include the provision of a duoplasmatron ion source and/or the provision of preacceleration bunching. Additional details are given later in this report. A series of measurements were carried out at the Tandem Dynamatron Facility involving the irradiation of a series of yttrium foils and the determination of activation cross sections using absolute counting techniques. The experimental work has been completed, and final analysis of the cross section data will be completed within several months

  20. Advanced plastic scintillators for fast neutron discrimination

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Patrick L [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Anstey, Mitchell [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Doty, F. Patrick [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Mengesha, Wondwosen [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2014-09-01

    The present work addresses the need for solid-state, fast neutron discriminating scintillators that possess higher light yields and faster decay kinetics than existing organic scintillators. These respective attributes are of critical importance for improving the gamma-rejection capabilities and increasing the neutron discrimination performance under high-rate conditions. Two key applications that will benefit from these improvements include large-volume passive detection scenarios as well as active interrogation search for special nuclear materials. Molecular design principles were employed throughout this work, resulting in synthetically tailored materials that possess the targeted scintillation properties.

  1. 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.

  2. Development of imaging techniques for fast neutron radiography in Japan

    International Nuclear Information System (INIS)

    Fujine, Shigenori; Yoneda, Kenji; Yoshii, Koji; Kamata, Masahiro; Tamaki, Masayoshi; Ohkubo, Kohei; Ikeda, Yasushi; Kobayashi, Hisao

    1999-01-01

    Neutron radiography with fast neutron beams (FNR) has been studied at the fast neutron source reactor 'YAYOI' of the University of Tokyo since 1986. Imaging techniques for FNR have been developed for CR-39 track-etch detector, electronic imaging system (television method), direct film method, imaging plate and also fast and thermal neutron concurrent imaging method. The review of FNR imaging techniques and some applications are reported in this paper

  3. Direct fast neutron detection: A status report

    Energy Technology Data Exchange (ETDEWEB)

    Peurrung, A.J.; Hansen, R.R.; Craig, R.A.; Hensley, W.K.; Hubbard, C.W.; Keller, P.E.; Reeder, P.L.; Sunberg, D.S.

    1997-12-01

    This report describes the status of efforts to develop direct fast-neutron detection via proton recoil within plastic scintillator. Since recording proton recoil events is of little practical use without a means to discriminate effectively against gamma-ray interactions, the present effort is concentrated on demonstrating a method that distinguishes between pulse types. The proposed method exploits the different pulse shapes that are to be expected primarily on the basis of the slower speed of the recoiling fission neutrons. Should this effort ultimately prove successful, the resulting novel technology will have the potential to significantly lower cost and increase capability for a number of critical neutron-detection applications. Considerable progress has been made toward a clear and compelling demonstration of this new technique. An exhaustive theoretical and numerical investigation of the method has been completed. The authors have been able to better understand the laboratory results and estimate the performance that could ultimately be achieved using the proposed technique. They have assessed the performance of a number of different algorithms for discriminating between neutron and gamma ray events. The results of this assessment will be critical when the construction of low-cost, field-portable neutron detectors becomes necessary. Finally, a laboratory effort to realize effective discrimination is well underway and has resulted in partial success.

  4. Direct fast neutron detection: A status report

    International Nuclear Information System (INIS)

    Peurrung, A.J.; Hansen, R.R.; Craig, R.A.; Hensley, W.K.; Hubbard, C.W.; Keller, P.E.; Reeder, P.L.; Sunberg, D.S.

    1997-12-01

    This report describes the status of efforts to develop direct fast-neutron detection via proton recoil within plastic scintillator. Since recording proton recoil events is of little practical use without a means to discriminate effectively against gamma-ray interactions, the present effort is concentrated on demonstrating a method that distinguishes between pulse types. The proposed method exploits the different pulse shapes that are to be expected primarily on the basis of the slower speed of the recoiling fission neutrons. Should this effort ultimately prove successful, the resulting novel technology will have the potential to significantly lower cost and increase capability for a number of critical neutron-detection applications. Considerable progress has been made toward a clear and compelling demonstration of this new technique. An exhaustive theoretical and numerical investigation of the method has been completed. The authors have been able to better understand the laboratory results and estimate the performance that could ultimately be achieved using the proposed technique. They have assessed the performance of a number of different algorithms for discriminating between neutron and gamma ray events. The results of this assessment will be critical when the construction of low-cost, field-portable neutron detectors becomes necessary. Finally, a laboratory effort to realize effective discrimination is well underway and has resulted in partial success

  5. Dosimetry and biological effects of fast neutrons

    International Nuclear Information System (INIS)

    Zoetelief, J.

    1981-01-01

    This thesis contains studies on two types of cellular damage: cell reproductive death and chromosome aberrations induced by irradiation with X rays, gamma rays and fast neutrons of different energies. A prerequisite for the performance of radiobiological experiments is the determination of the absorbed dose with a sufficient degree of accuracy and precision. Basic concepts of energy deposition by ionizing radiation and practical aspects of neutron dosimetry for biomedical purposes are discussed. Information on the relative neutron sensitivity of GM counters and on the effective point of measurement of ionization chambers for dosimetry of neutron and photon beams under free-in-air conditions and inside phantoms which are used to simulate the biological objects is presented. Different methods for neutron dosimetry are compared and the experimental techniques used for the investigations of cell reproductive death and chromosome aberrations induced by ionizing radiation of different qualities are presented. Dose-effect relations for induction cell inactivation and chromsome aberrations in three cultured cell lines for different radiation qualities are presented. (Auth.)

  6. MPACT Fast Neutron Multiplicity System Design Concepts

    Energy Technology Data Exchange (ETDEWEB)

    D. L. Chichester; S. A. Pozzi; J. L. Dolan; M. T. Kinlaw; A. C. Kaplan; M. Flaska; A. Enqvist; J. T. Johnsom; S. M. Watson

    2012-10-01

    This report documents work performed by Idaho National Laboratory and the University of Michigan in fiscal year (FY) 2012 to examine design parameters related to the use of fast-neutron multiplicity counting for assaying plutonium for materials protection, accountancy, and control purposes. This project seeks to develop a new type of neutron-measurement-based plutonium assay instrument suited for assaying advanced fuel cycle materials. Some current-concept advanced fuels contain high concentrations of plutonium; some of these concept fuels also contain other fissionable actinides besides plutonium. Because of these attributes the neutron emission rates of these new fuels may be much higher, and more difficult to interpret, than measurements made of plutonium-only materials. Fast neutron multiplicity analysis is one approach for assaying these advanced nuclear fuels. Studies have been performed to assess the conceptual performance capabilities of a fast-neutron multiplicity counter for assaying plutonium. Comparisons have been made to evaluate the potential improvements and benefits of fast-neutron multiplicity analyses versus traditional thermal-neutron counting systems. Fast-neutron instrumentation, using for example an array of liquid scintillators such as EJ-309, have the potential to either a) significantly reduce assay measurement times versus traditional approaches, for comparable measurement precision values, b) significantly improve assay precision values, for measurement durations comparable to current-generation technology, or c) moderating improve both measurement precision and measurement durations versus current-generation technology. Using the MCNPX-PoliMi Monte Carlo simulation code, studies have been performed to assess the doubles-detection efficiency for a variety of counter layouts of cylindrical liquid scintillator detector cells over one, two, and three rows. Ignoring other considerations, the best detector design is the one with the most

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

    Science.gov (United States)

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

  8. Induced mutation breeding by fast neutron

    International Nuclear Information System (INIS)

    Chen Zhengba; You Risheng

    1988-09-01

    The high-yield and long-grain new variety 'Zhongtie 31' was developed through five generations after irradiation of the rice variety 'Tieqiu 15' dried seeds by 14 MeV fast neutrons with a fluence of (1.33 ∼ 3.33) x 10 11 neutrons cm -2 . It matured earlier 3 to 5 days, the plant is higher 10 cm, bigger ear, more grain than its original variety 'tieqiu 15', and the yield increased by 19.2% to 30.7%. The source of new variety 'Zhongtie 31' was proved by the isoenzyme genetics. In field test, it increased by 7% to 10% as compared with high-yield variety 'Guichao No.2' and the hybrid rive 'Shanyou No.2', and is more palatable. The new variety was initiated by irradiation mutagensis routine rice, its well-grown and bumper-yield performances may be compared favourably with hybrid rice variety. In July 1986, the new variety 'Zhongtie 31' was obtained by inducing mutation with fast neutron. The same year, the planted area of 'Zhongtie 31' has achieved upto 250 thousand mu (1.67 x 10 8 cm 2 )

  9. Image reconstruction from Pulsed Fast Neutron Analysis

    International Nuclear Information System (INIS)

    Bendahan, Joseph; Feinstein, Leon; Keeley, Doug; Loveman, Rob

    1999-01-01

    Pulsed Fast Neutron Analysis (PFNA) has been demonstrated to detect drugs and explosives in trucks and large cargo containers. PFNA uses a collimated beam of nanosecond-pulsed fast neutrons that interact with the cargo contents to produce gamma rays characteristic to their elemental composition. By timing the arrival of the emitted radiation to an array of gamma-ray detectors a three-dimensional elemental density map or image of the cargo is created. The process to determine the elemental densities is complex and requires a number of steps. The first step consists of extracting from the characteristic gamma-ray spectra the counts associated with the elements of interest. Other steps are needed to correct for physical quantities such as gamma-ray production cross sections and angular distributions. The image processing includes also phenomenological corrections that take into account the neutron attenuation through the cargo, and the attenuation of the gamma rays from the point they were generated to the gamma-ray detectors. Additional processing is required to map the elemental densities from the data acquisition system of coordinates to a rectilinear system. This paper describes the image processing used to compute the elemental densities from the counts observed in the gamma-ray detectors

  10. Methods and Instruments for Fast Neutron Detection

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, David V.; Reeder, Paul L.; Cooper, Matthew W.; McCormick, Kathleen R.; Peurrung, Anthony J.; Warren, Glen A.

    2005-05-01

    Pacific Northwest National Laboratory evaluated the performance of a large-area (~0.7 m2) plastic scintillator time-of-flight (TOF) sensor for direct detection of fast neutrons. This type of sensor is a readily area-scalable technology that provides broad-area geometrical coverage at a reasonably low cost. It can yield intrinsic detection efficiencies that compare favorably with moderator-based detection methods. The timing resolution achievable should permit substantially more precise time windowing of return neutron flux than would otherwise be possible with moderated detectors. The energy-deposition threshold imposed on each scintillator contributing to the event-definition trigger in a TOF system can be set to blind the sensor to direct emission from the neutron generator. The primary technical challenge addressed in the project was to understand the capabilities of a neutron TOF sensor in the limit of large scintillator area and small scintillator separation, a size regime in which the neutral particle’s flight path between the two scintillators is not tightly constrained.

  11. Fast Neutron Spectroscopy using a CLYC array

    Science.gov (United States)

    Doucet, Emery; Brown, T.; Chowdhury, P.; Lister, C. J.; Wilson, G. L.; Devlin, M.; Mosby, S.

    2015-10-01

    A new inorganic scintillator, Cs2LiYCl6, or CLYC, has recently shown great promise as a dual gamma-neutron detector, where neutron-gamma discrimination is achieved through digital pulse shape processing. The 35Cl(n,p) reaction allows fast neutrons to be measured with an energy resolution of ~10 %. Following initial tests with natural Li, 6Li-depleted crystals were chosen to reduce the strong thermal capture response of 6Li. A 16-element array of 1'' x 1'' 6Li-depleted CLYC crystals is being tested in a variety of applications. A VME-based digital DAQ is used for pulse shape discrimination and extracting energies. The array was deployed at the LANSCE WNR facility, to measure elastic and inelastic scattering cross sections of neutrons on 56Fe and 238U. The data acquisition and analysis software were originally based on Python. The sorting codes were re-written in C, which sped up the analysis by two orders of magnitude. Most of the sorting code is within the framework of the CERN-ROOT software. Details of the detector array and the analysis will be presented. Supported by NNSA-SSAA program through DOE Grant DE-NA00013008.

  12. Optimisation of resolution in accelerator-based fast neutron radiography

    CERN Document Server

    Rahmanian, H; Watterson, J I W

    2002-01-01

    In fast neutron radiography, imaging geometry, neutron scattering, the fast neutron scintillator and the position-sensitive detector all influence feature contrast, resolution and the signal-to-noise ratio in the image. The effect of imaging geometry can be explored by using a ray-tracing method. This requires following the path of neutrons through the imaging field, which includes the sample of interest. A relationship between imaging geometry and feature detectability can be developed. Monte Carlo methods can be used to explore the effect of neutron scattering on the results obtained with the ray-tracing technique. Fast neutrons are detected indirectly via neutron-nucleon scattering reactions. Using hydrogen-rich scintillators and relying on the recoil protons to ionise the scintillator material is the most sensitive technique available. The efficiency, geometry and composition of these scintillators influence the detectability of features in fast neutron radiography. These scintillator properties have a di...

  13. Fast neutron spectrometer with pulse shape discrimination

    International Nuclear Information System (INIS)

    Verbitsky, S.S.

    1978-01-01

    A fast neutron spectrometer with a stilbene single crystal designed to operate at high pulsed count rate has been described. Making use of identification and rejection of events, accompanied by pile-up, allowed to increase permissible count rates by an order of magnitude. The results of energy dependence of signal amplitude and shape relative anisotropy in stilbene in the range 4-10 and 2-8 MeV respectively have been presented. Taking into account anisotropy of the detector-scintillation properties allowed to improve particle discrimination. (Auth.)

  14. Fast-neutron solid-state dosimeter

    International Nuclear Information System (INIS)

    Kecker, K.H.; Haywood, F.F.; Perdue, P.T.; Thorngate, J.H.

    1975-01-01

    This patent relates to an improved fast-neutron solid-state dosimeter that does not require separation of materials before it can be read out, that utilizes materials that do not melt or otherwise degrade at about 300 0 C readout temperature, that provides a more efficient dosimeter, and that can be reused. The dosimeters are fabricated by intimately mixing a TL material, such as CaSO 4 :Dy, with a powdered polyphenyl, such as p-sexiphenyl, and hot-pressing the mixture to form pellets, followed by out-gassing in a vacuum furnace at 150 0 C prior to first use dosimeters

  15. Core of a fast neutron nuclear reactor

    International Nuclear Information System (INIS)

    Giacometti, Christian; Mougniot, J.-C.; Ravier, Jean.

    1974-01-01

    The fast neutron nuclear reactor described includes an internal area in fissile material completely enclosed in an area of fertile material forming the outside blanket. The internal fissile area is provided with housings exclusively filled with fertile material forming one or more inside blankets. In this core the internal blankets are shaped like rings vertically separating superimposed rings of fissile material. The blanket of material nearest to the periphery is circumscribed externally by a contour having an indented shape on its straight section so as to increase the contact area between this blanket and the external blanket [fr

  16. Fast-neutron coincidence-counter manual

    International Nuclear Information System (INIS)

    Ensslin, N.; Atwell, T.L.; Lee, D.M.; Erkkila, B.; Marshall, R.S.; Morgan, A.; Shonrock, C.; Tippens, B.; Van Lyssel, T.

    1982-03-01

    The fast neutron counter (FNC) described in this report is a computer-based assay system employing fast-pulse counting instrumentation. It is installed below a glove box in the metal electrorefining area of the Los Alamos National Laboratory Plutonium Processing Facility. The instrument was designed to assay plutonium salts and residues from this process and to verify the mass of electrorefined metal. Los Alamos National Laboratory Groups Q-1, Q-3, and CMB-11 carried out a joint test and evaluation plan of this instrument between May 1978 and May 1979. The results of that evaluation, a description of the FNC, and operating instructions for further use are given in this report

  17. MPACT Fast Neutron Multiplicity System Prototype Development

    Energy Technology Data Exchange (ETDEWEB)

    D.L. Chichester; S.A. Pozzi; J.L. Dolan; M.T. Kinlaw; S.J. Thompson; A.C. Kaplan; M. Flaska; A. Enqvist; J.T. Johnson; S.M. Watson

    2013-09-01

    This document serves as both an FY2103 End-of-Year and End-of-Project report on efforts that resulted in the design of a prototype fast neutron multiplicity counter leveraged upon the findings of previous project efforts. The prototype design includes 32 liquid scintillator detectors with cubic volumes 7.62 cm in dimension configured into 4 stacked rings of 8 detectors. Detector signal collection for the system is handled with a pair of Struck Innovative Systeme 16-channel digitizers controlled by in-house developed software with built-in multiplicity analysis algorithms. Initial testing and familiarization of the currently obtained prototype components is underway, however full prototype construction is required for further optimization. Monte Carlo models of the prototype system were performed to estimate die-away and efficiency values. Analysis of these models resulted in the development of a software package capable of determining the effects of nearest-neighbor rejection methods for elimination of detector cross talk. A parameter study was performed using previously developed analytical methods for the estimation of assay mass variance for use as a figure-of-merit for system performance. A software package was developed to automate these calculations and ensure accuracy. The results of the parameter study show that the prototype fast neutron multiplicity counter design is very nearly optimized under the restraints of the parameter space.

  18. Boron neutron capture therapy (BNCT) using fast neutrons: Effects in two human tumor cell lines

    International Nuclear Information System (INIS)

    Sauerwein, W.; Ziegler, W.; Szypniewski, H.; Streffer, C.

    1990-01-01

    The results demonstrate that the effect of fast neutrons on cell survival in cell culture can be enhanced by boron neutron capture reaction. Even with lower enhancement ratios, the concept of NCT assisted fast neutron therapy may successfully be applied for tumor treatment with the Essen cyclotron. (orig.)

  19. Transmutation of Americium in Fast Neutron Facilities

    International Nuclear Information System (INIS)

    Zhang, Youpeng

    2011-01-01

    In this thesis, the feasibility to use a medium sized sodium cooled fast reactor fully loaded with MOX fuel for efficient transmutation of americium is investigated by simulating the safety performance of a BN600-type fast reactor loaded with different fractions of americium in the fuel, using the safety parameters obtained with the SERPENT Monte Carlo code. The focus is on americium mainly due to its long-term contribution to the radiotoxicity of spent nuclear fuel and its deterioration on core's safety parameters. Applying the SAS4A/SASSYS transient analysis code, it is demonstrated that the power rating needs to be reduced by 6% for each percent additional americium introduction into the reference MOX fuel, maintaining 100 K margin to fuel melting, which is the most limiting failure mechanism. Safety analysis of a new Accelerator Driven System design with a smaller pin pitch-to-diameter ratio comparing to the reference EFIT-400 design, aiming at improving neutron source efficiency, was also performed by simulating performance for unprotected loss of flow, unprotected transient overpower, and protected loss-of-heat-sink transients, using neutronic parameters obtained from MCNP calculations. Thanks to the introduction of the austenitic 15/15Ti stainless steel with enhanced creep rupture resistance and acceptable irradiation swelling rate, the suggested ADS design loaded with nitride fuel and cooled by lead-bismuth eutectic could survive the full set of transients, preserving a margin of 130 K to cladding rupture during the most limiting transient. The thesis concludes that efficient transmutation of americium in a medium sized sodium cooled fast reactor loaded with MOX fuel is possible but leads to a severe power penalty. Instead, preserving transmutation rates of minor actinides up to 42 kg/TWh th , the suggested ADS design with enhanced proton source efficiency appears like a better option for americium transmutation

  20. Activation measurements for fast neutrons. Part E. Evaluation of fast neutron 63Ni transmission factors

    International Nuclear Information System (INIS)

    Egbert, Stephen D.

    2005-01-01

    The 63 Ni measurements for fast neutrons in copper samples are compared to the calculated free-in-air 63 Ni neutron activation given in Chapter 3 by use of transmission factors. Transmission factors were calculated to account for the modification of the fluence and activation at each sample's in situ location. For the purposes of this discussion, the transmission factor (TF) is defined as the ratio of the in situ sample activation divided by the untilted free-in-air (FIA) activation at a height of 1 m above ground at the same ground range. Examples of the application of TF's will be provided in this section. (author)

  1. Feasibility of the Precise Energy Calibration for Fast Neutron Spectrometers

    Science.gov (United States)

    Gaganov, V. V.; Usenko, P. L.; Kryzhanovskaja, M. A.

    2017-12-01

    Computational studies aimed at improving the accuracy of measurements performed using neutron generators with a tritium target were performed. A measurement design yielding an extremely narrow peak in the energy spectrum of DT neutrons was found. The presence of such a peak establishes the conditions for precise energy calibration of fast-neutron spectrometers.

  2. A clinical trial of fast neutron therapy for malignant melanoma

    International Nuclear Information System (INIS)

    Tsunemoto, Hiroshi; Morita, Shinroku; Ishikawa, Tatsuo

    1985-01-01

    Fifty-four patients with malignant melanoma of the skin or the head and neck underwent fast neutron therapy between November 1975 and March 1983. Of these patients, 21 patients with melanoma of the skin and 12 patients with melanoma of the head and neck were chosen as subjects for this study. Of the 21 patients with skin lesions, complete regression was seen in 2 patients undergoing fast neutron therapy alone and in 17 patients undergoing fast neutron therapy combined with salvage surgery. A cumulative five-year survival rate was 47 %. Preoperative fast neutron therapy is a promising method used in the treatment of malignant melanoma. Two of 12 patients with advanced melanoma of the head and neck were long-term survivors. Fast neutron-induced skin damage was seen in one of the 33 patients. (Namekawa, K.)

  3. Current Amplification Characteristics of BJT on Fast Neutron Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Sung Ho; Sun, Gwang Min; Baek, Hani [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    BJT (Bipolar Junction Transistor) is a three-terminal device with an important feature in that the current through two terminals can be controlled by small changes we make in the current or voltage at the third terminal. This control feature allows us to amplify small AC signals or to switch the device from an on state and off state and back. Fast neutron irradiation incurs lattice damage in bulk Si. The recombination rate of minority carriers and register are increased by the lattice damage. This study will investigate the current amplification characteristics of a pnp Si BJT through fast neutron irradiation experiments. In this paper, the current amplification characteristics of a pnp Si BJT were investigated for fast neutron irradiation. The experimental results show that base-tocollector current amplification ratio is decreased with an increase in the fast neutron irradiation. These indicate that the lattice damage caused by fast neutron irradiation increases the recombination rate of minority carriers and resistor.

  4. Some experiments upon the biological effects of fast neutrons

    International Nuclear Information System (INIS)

    Gray, L.H.; Mottram, J.C.; Read, J.; Spear, F.G.

    1995-01-01

    This paper: ''Some experiments upon the biological effects of fast neutrons'', was written by four renowned scientists of their time only 8 years after the discovery of neutrons by Chadwick. The paper describes the methods of measurement of neutron dose and a series of radiobiology experiments on chick embryo fibroblasts and the inhibition of mitosis in the bean root. The results are interesting to compare with current thinking on the radiobiology of neutrons. (UK)

  5. An improved fast neutron radiography quantitative measurement method

    International Nuclear Information System (INIS)

    Matsubayashi, Masahito; Hibiki, Takashi; Mishima, Kaichiro; Yoshii, Koji; Okamoto, Koji

    2004-01-01

    The validity of a fast neutron radiography quantification method, the Σ-scaling method, which was originally proposed for thermal neutron radiography was examined with Monte Carlo calculations and experiments conducted at the YAYOI fast neutron source reactor. Water and copper were selected as comparative samples for a thermal neutron radiography case and a dense object, respectively. Although different characteristics on effective macroscopic cross-sections were implied by the simulation, the Σ-scaled experimental results with the fission neutron spectrum cross-sections were well fitted to the measurements for both the water and copper samples. This indicates that the Σ-scaling method could be successfully adopted for quantitative measurements in fast neutron radiography

  6. Television imaging system for fast neutron radiography using baby cyclotron

    International Nuclear Information System (INIS)

    Yoshii, Koji; Miya, Kenzo; Katoh, Norihiko.

    1993-01-01

    A television imaging system for fast neutron radiography (FNR-TV) developed using the fast neutron source reactor YAYOI was applied to the baby-cyclotron based fast neutron source to get images of thick objects quickly. In the system the same technique as a current television imaging system of thermal neutron radiography was applied, while the luminescent converter was used to detect fast neutrons. Using the CR39 track etch method it took about 7 h to get an image, while the FNR-TV only 20 s enough for taking the same object. However the FNR-TV imaging result of the simulation model of a large explosive device for the space launch vehicle of H-2 type was not so good as the image taken with the CR39 track etch method. The reason was that the luminescence intensity of the FNR-TV converter was a quarter of that in the YAYOI. (author)

  7. Fast neutron boost for the treatment of grade IV astrocytomas

    International Nuclear Information System (INIS)

    Breteau, N.; Destembert, B.; Favre, A.; Pheline, C.; Schlienger, M.

    1989-01-01

    A previous study, on grade IV astrocytomas, compared a combination of photons and fast neutron boost to photons only, both treatments being delivered following a concentrated irradiation schedule. A slight improvement in survival was observed after neutron boost for non operated patients, but not for operated patients. Since death was always related to local recurrence and since no complication occurred after neutron boost, the neutron dose was increased from 6 to 7 Gy in January 1985. No improvement in survival was observed for patients treated with neutron boost after complete resection. After subtotal resection, the group that was treated with the higher neutron boost (7 Gy) showed a significant benefit in survival at twelve months. When patients had only a biopsy before irradiation, there was a benefit in survival after neutron boost, but no additional benefit was gained when the size of the neutron boost was increased from 6 to 7 Gy. (orig.) [de

  8. C7LYC Scintillators and Fast Neutron Spectroscopy

    Science.gov (United States)

    Chowdhury, P.; Brown, T.; Doucet, E.; Lister, C. J.; Wilson, G. L.; D'Olympia, N.; Devlin, M.; Mosby, S.

    2016-09-01

    Cs2 LiYCl6 (CLYC) scintillators detect both gammas and neutrons with excellent pulse shape discrimination. At UML, fast neutron measurements with a 16-element 1''x1'' CLYC array show promise for low energy nuclear science. CLYC detects fast neutrons via the 35Cl (n,p) reaction (resolution < 10 % at < 8 MeV). In our 7Li-enriched C7LYC, the thermal neutron response from the 6Li(n, α)t reaction is virtually eliminated. The low intrinsic efficiency of CLYC for fast neutrons (< 1 %) is offset by increased solid angle with the array placed near the target, since TOF is not needed for energy resolution. The array was tested at LANL for measuring elastic and inelastic neutron scattering on 56Fe. The incident energy from the white neutron source was measured via TOF, and the scattered neutron energy via the pulse height in CLYC. The array was also tested at CARIBU for measuring beta-delayed neutrons. Larger CLYC crystals are now a reality. Measurements with the first 3'' x 3'' C7LYC crystal are in progress at UML. Results will be discussed in the context of constructing a C7LYC array at FRIB for reaction and decay spectroscopy of neutron-rich fragments. Supported by the NNSA Stewardship Science Academic Alliance Program under Grant DE-NA00013008.

  9. Conceptual design, neutronic and radioprotection study of a fast neutron irradiation station at SINQ

    International Nuclear Information System (INIS)

    Zanini, L.; Baluc, N.; Simone, A. De; Eichler, R.; Joray, S.; Manfrin, E.; Pouchon, M.; Rabaioli, S.; Schumann, D.; Welte, J.; Zhernosekov, K.

    2011-12-01

    This comprehensive, illustrated report by the Paul Scherrer Institute PSI in Switzerland documents the proposals concerning the conceptual design, neutronic and radioprotection study of a fast neutron irradiation station at the PSI's Swiss Spallation Neutron Source SINQ facility. The need for fast neutron irradiation is discussed and the possibility of using SINQ as a fast neutron irradiation facility is considered. The production of isotopes, tracers and medical isotopes is discussed, as are fission and fusion reactor technologies. The characteristics of the neutron spectrum in SINQ are discussed. The neutronic and radioprotection calculations for an irradiation station at SINQ are looked at in detail and extensive examples of work done and results obtained are presented and discussed. Radioprotection issues are also looked at. Further contributions in the report cover the hot/cold irradiation station in the SINQ target. An appendix provides detailed drawings of the facility's pneumatic delivery system

  10. Spectral unfolding of fast neutron energy distributions

    Science.gov (United States)

    Mosby, Michelle; Jackman, Kevin; Engle, Jonathan

    2015-10-01

    The characterization of the energy distribution of a neutron flux is difficult in experiments with constrained geometry where techniques such as time of flight cannot be used to resolve the distribution. The measurement of neutron fluxes in reactors, which often present similar challenges, has been accomplished using radioactivation foils as an indirect probe. Spectral unfolding codes use statistical methods to adjust MCNP predictions of neutron energy distributions using quantified radioactive residuals produced in these foils. We have applied a modification of this established neutron flux characterization technique to experimentally characterize the neutron flux in the critical assemblies at the Nevada National Security Site (NNSS) and the spallation neutron flux at the Isotope Production Facility (IPF) at Los Alamos National Laboratory (LANL). Results of the unfolding procedure are presented and compared with a priori MCNP predictions, and the implications for measurements using the neutron fluxes at these facilities are discussed.

  11. Development of a fast, thermal neutron, and gamma ray component discriminator

    International Nuclear Information System (INIS)

    Yoneda, K.; Kobayashi, H.

    1996-01-01

    A fast neutron, thermal neutron, and gamma ray component (FTG) discriminator is proposed in this study. The FTG discriminator was tested using neutron beams generated from the YAYOI fast neutron reactor and the Kyoto University Research Reactor. Various beams were successfully discriminated into fast, thermal, cold neutrons and gamma rays. The measurement technique and the reliability of the FTG discriminator are discussed. (orig.)

  12. Determination of fast neutron flux distribution in irradiation sites of the Malaysian Nuclear Agency research reactor

    International Nuclear Information System (INIS)

    Yavar, A.R.; Sarmani, S.B.; Wood, A.K.; Fadzil, S.M.; Radir, M.H.; Khoo, K.S.

    2011-01-01

    Determination of thermal to fast neutron flux ratio (f fast ) and fast neutron flux (φ fast ) is required for fast neutron reactions, fast neutron activation analysis, and for correcting interference reactions. The f fast and subsequently φ fast were determined using the absolute method. The f fast ranged from 48 to 155, and the φ fast was found in the range 1.03x10 10 -4.89x10 10 n cm -2 s -1 . These values indicate an acceptable conformity and applicable for installation of the fast neutron facility at the MNA research reactor.

  13. Delayed neutron yield from fast neutron induced fission of 238U

    International Nuclear Information System (INIS)

    Piksaikin, V.M.; Kazakov, L.E.; Isaev, S.G.; Roshchenko, V.A.; Goverdovski, A.A.; Tertytchnyi, R.G.

    2002-01-01

    The measurements of the total delayed neutron yield from fast neutron induced fission of 238 U were made. The experimental method based on the periodic irradiation of the fissionable sample by neutrons from a suitable nuclear reaction had been employed. The preliminary results on the energy dependence of the total delayed neutron yield from fission of 238 U are obtained. According to the comparison of experimental data with our prediction based on correlation properties of delayed neutron characteristics, it is concluded that the value of the total delayed neutron yield near the threshold of (n,f) reaction is not a constant. (author)

  14. Delayed neutron yield from fast neutron induced fission of sup 2 sup 3 sup 8 U

    CERN Document Server

    Piksaikin, V M; Isaev, S G; Kazakov, L E; Roshchenko, V A; Tertytchnyi, R G

    2001-01-01

    The measurements of the total delayed neutron yield from fast neutron induced fission of sup 2 sup 3 sup 8 U were made. The experimental method based on the periodic irradiation of the fissionable sample by neutrons from a suitable nuclear reaction had been employed. The preliminary results on the energy dependence of the total delayed neutron yield from fission of sup 2 sup 3 sup 8 U are obtained. According to the comparison of experimental data with our prediction based on correlation properties of delayed neutron characteristics, it is concluded that the value of the total delayed neutron yield near the threshold of (n,f) reaction is not a constant.

  15. Correlation properties of delayed neutrons from fast neutron induced fission

    International Nuclear Information System (INIS)

    Piksaikin, V.M.; Isaev, S.G.

    1998-01-01

    The experimental studies of the energy dependence of the delayed neutron parameters for various fissioning systems has shown that the behavior of a some combination of delayed neutron parameters (group relative abundances a i and half lives T i ) has a similar features. On the basis of this findings the systematics of delayed neutron experimental data for thorium, uranium, plutonium and americium isotopes have been investigated with the purpose to find a correlation of DN parameters with characteristics of fissioning system as well as a correlation between the delayed neutron parameters themselves. Below we will present the preliminary results which were obtained during this study omitting the physics interpretation of the results. (author)

  16. Fast neutron sensitivity of polymer dosemeters

    International Nuclear Information System (INIS)

    Harper, M.W.; Pearson, D.W.; Moran, P.R.

    1975-01-01

    The responses of polymer thermocurrent dosemeters to fission spectrum and 14 MeV neutrons were measured. The dosemeters are in the form of disks 1 cm diam by 0.5 mm thick. Relative to Cobalt 60 gamma responses, teflon PTFE dosemeters show a 6 percent response to 14 MeV neutrons and a 5 percent response to fission neutrons on a tissue rad basis. Polymethylpentene dosemeters show a 49 percent response to 14 MeV neutrons and a 40 percent response to fission neutrons on a tissue rad basis when provided with adequate recoil proton buildup. The sensitivity of these dosemeters is limited to neutron doses greater than 10 rads by spurious background currents

  17. A new neutron noise technique for fast reactors

    International Nuclear Information System (INIS)

    Zhuo Fengguan; Jin Manyi; Yao Shigui; Su Zhuting

    1987-12-01

    This paper gives a new neutron noise technique for fast reactors, which is known as thermalization measurement technique of the neutron noise. The theoretical formulas of the technique were developed, and a digital delayed coincidence time analyzer consisted of TTL integrated circuits was constructed for the study of this technique. The technique has been tested and applied practically at Df-VI fast zero power reactor. It was shown that the provided technique in this work has a number of significant advantages in comparison with the conventional neutron noise method

  18. Modeling delayed neutron monitoring systems for fast breeder reactors

    International Nuclear Information System (INIS)

    Bunch, W.L.; Tang, E.L.

    1983-10-01

    The purpose of the present work was to develop a general expression relating the count rate of a delayed neutron monitoring system to the introduction rate of fission fragments into the sodium coolant of a fast breeder reactor. Most fast breeder reactors include a system for detecting the presence of breached fuel that permits contact between the sodium coolant and the mixed oxide fuel. These systems monitor for the presence of fission fragments in the sodium that emit delayed neutrons. For operational reasons, the goal is to relate the count rate of the delayed neutron monitor to the condition of the breach in order that appropriate action might be taken

  19. Fast neutron activation analysis at Texas A and M University

    International Nuclear Information System (INIS)

    James, W.D.

    1997-01-01

    Fast neutron generators are used at Texas A and M University to provide a supply of high energy neutrons for nuclear analytical measurements. A series of neutron activation analysis procedures have been developed for determining various major, minor and trace constituents in a variety of materials. These procedures are primarily developed to compliment our reactor based NAA program, thereby expanding the list of determinable elements to include those difficult or impossible to measure using thermal neutrons. A few typical methods are discussed. The unique implementation of the methodologies at Texas A and M are explained. (author)

  20. Fast counting electronics for neutron coincidence counting

    International Nuclear Information System (INIS)

    Swansen, J.E.

    1987-01-01

    This patent describes a high speed circuit for accurate neutron coincidence counting comprising: neutron detecting means for providing an above-threshold signal upon neutron detection; amplifying means inputted by the neutron detecting means for providing a pulse output having a pulse width of about 0.5 microseconds upon the input of each above threshold signal; digital processing means inputted by the pulse output of the amplifying means for generating a pulse responsive to each input pulse from the amplifying means and having a pulse width of about 50 nanoseconds effective for processing an expected neutron event rate of about 1 Mpps: pulse stretching means inputted by the digital processing means for producing a pulse having a pulse width of several milliseconds for each pulse received form the digital processing means; visual indicating means inputted by the pulse stretching means for producing a visual output for each pulse received from the digital processing means; and derandomizing means effective to receive the 50 ns neutron event pulses from the digital processing means for storage at a rate up to the neutron event rate of 1 Mpps and having first counter means for storing the input neutron event pulses

  1. Accidental fast neutron dosimetry by means of plastic identity cards

    International Nuclear Information System (INIS)

    Lommler, B.; Pitt, E.; Scharmann, A.; Simmer, R.

    1991-01-01

    Identity cards designed to provide high security against falsification are often composed of polymeric compounds and a paper-like inlay containing the identifying information. This system may be considered as a fast neutron detector when certain boundary conditions, especially concerning the polymer are fulfilled. The track recording properties of the plastic envelope of a widely used identity card were investigated. Recoil tracks induced by fast neutrons were revealed by electrochemical etching in 5N NaOH in a thin cover mounted on a trick etch-resistant base. The etching parameters (etchant normality, temperature, time, field strength, frequency) were optimized to achieve maximum neutron sensitivity. The response for neutrons from a CF 252 source is about one per cent of that of the widely used CR-39 track detector material. The possible use of the identity card as an etch track detector in accidental neutron dosimetry is discussed. (author)

  2. Dosimetric properties of the fast neutron therapy beams at TAMVEC

    International Nuclear Information System (INIS)

    Almond, P.R.; Smith, A.R.; Smathers, J.R.; Otte, V.A.

    1975-01-01

    In October 1972, M.D. Anderson Hospital and Tumor Institute of the University of Texas System Cancer Center initiated a clinical trial of fast neutron radiotherapy using the cyclotron at Texas A and M University. Initially, the study used neutrons produced by bombarding beryllium with 16 MeV deuterons, but since March, 1973, neutrons from 50 MeV deuterons have been used. The dosimetric properties of the 30 MeV beams have also been measured for comparison with the neutron beams from D-T generators. The three beams are compared in terms of dose rate, skin sparing, depth dose and field flatness. Isodose curves for treatment planning were generated using the decrement line method and compared to curves measured by a computer controlled isodose plotter. This system was also used to measure the isodose curves for wedge fields. Dosimetry checks on various patients were made using silicon diodes as in vivo fast neutron dosimeters

  3. Fast neutron radiotherapy in the treatment of malignant pleural mesothelioma.

    Science.gov (United States)

    Patel, Shilpen A; Kusano, Aaron S; Truong, Anh; Stelzer, Keith J; Laramore, George E

    2015-02-01

    Malignant pleural mesothelioma (MPM) is a fatal disease lacking standardized treatment. We describe the use of fast neutron radiation therapy in MPM patients referred to the Department of Radiation Oncology at the University of Washington Medical Center. Retrospective chart review of MPM patients receiving neutron radiotherapy treatment from 1980 to 2012. A total of 30 MPM patients received fast neutron radiotherapy as part of their treatment regimen. Median age at diagnosis was 59.6 years (range, 46.6 to 72.3 y). Eighteen patients received fast neutron radiotherapy as a component of trimodality treatment. Median overall survival was 20.3 months (range, 5.5 to 73.3 mo) with 1 patient censored at 34.8 months and all other patients with confirmed dates of death. One patient receiving radiotherapy alone as a palliative measure died during radiation treatment. One patient was unable to tolerate radiotherapy and stopped before completing prescribed treatment. On univariate analysis, Brigham Stage at presentation was a significant predictor of survival (Ptreatment compared to those who did not. Fast neutron radiotherapy may be utilized in the management of MPM patients. However, treatment with fast neutron radiotherapy did not significantly improvement outcome, even when used in a trimodality regimen.

  4. Development of a double scintillator fast neutron spectrometer

    International Nuclear Information System (INIS)

    Shirakata, Keisho; Iijima, Tsutomu; Cho, Mann.

    1976-03-01

    A double scintillator fast neutron spectrometer based on the time-of-flight measurement between two plastic scintillators has been developed for spectrum measurement in FCA cores and other fast systems. Neutrons extracted from a fast system are scattered by the 1st scintillator and the 2nd scintillator detects the scattered neutrons. By measuring the time-of-flight between the two scintillators, the neutron spectrum is determined. The method is essentially differential, and a complicated unfolding process is not required. The results of its application indicate excellence of the method over other methods in the energy range above several hundreds keV. Design and characteristics of the spectrometer, application, analysis of the measured data are described in detail. (auth.)

  5. Elemental analysis of fertilizer by fast neutron activation

    International Nuclear Information System (INIS)

    Bodart, F.; Deconninck, G.

    1977-01-01

    A simple and accurate technique has been developed to analyse commercial fertilizers for phosphorus, potassium, chlorine, magnesium and silicon. The method is based on fast-neutron activation using a neutron flux of 2x10 11 neutrons/second. The optimum analytical conditions are tabulated. After irradiation, the sample is measured on a conventional counting system including a Ge(Li) detector (10% efficiency and 2 keV resolution for 60 Co) and a multichannel analyser. Monitor foils radioactivity are measured separately at the same time with a 2''x2''NaI detector coupled with a single channel analyser and a scaler. Fast neutron activation has proved to be a fast, simple, reliable and low cost analytical technique for the determination of phosphorus, silicon, potassium, magnesium and chlorine in fertilizers. Not less than five phosphorus determinations are possible in one hour, while two potassium, magnesium and chlorine determinations are made at the same time. (T.G.)

  6. Design of a transportable high efficiency fast neutron spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Roecker, C., E-mail: calebroecker@berkeley.edu [Department of Nuclear Engineering, University of California at Berkeley, CA 94720 (United States); Bernstein, A.; Bowden, N.S. [Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Cabrera-Palmer, B. [Radiation and Nuclear Detection Systems, Sandia National Laboratories, Livermore, CA 94550 (United States); Dazeley, S. [Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Gerling, M.; Marleau, P.; Sweany, M.D. [Radiation and Nuclear Detection Systems, Sandia National Laboratories, Livermore, CA 94550 (United States); Vetter, K. [Department of Nuclear Engineering, University of California at Berkeley, CA 94720 (United States); Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2016-08-01

    A transportable fast neutron detection system has been designed and constructed for measuring neutron energy spectra and flux ranging from tens to hundreds of MeV. The transportability of the spectrometer reduces the detector-related systematic bias between different neutron spectra and flux measurements, which allows for the comparison of measurements above or below ground. The spectrometer will measure neutron fluxes that are of prohibitively low intensity compared to the site-specific background rates targeted by other transportable fast neutron detection systems. To measure low intensity high-energy neutron fluxes, a conventional capture-gating technique is used for measuring neutron energies above 20 MeV and a novel multiplicity technique is used for measuring neutron energies above 100 MeV. The spectrometer is composed of two Gd containing plastic scintillator detectors arranged around a lead spallation target. To calibrate and characterize the position dependent response of the spectrometer, a Monte Carlo model was developed and used in conjunction with experimental data from gamma ray sources. Multiplicity event identification algorithms were developed and used with a Cf-252 neutron multiplicity source to validate the Monte Carlo model Gd concentration and secondary neutron capture efficiency. The validated Monte Carlo model was used to predict an effective area for the multiplicity and capture gating analyses. For incident neutron energies between 100 MeV and 1000 MeV with an isotropic angular distribution, the multiplicity analysis predicted an effective area of 500 cm{sup 2} rising to 5000 cm{sup 2}. For neutron energies above 20 MeV, the capture-gating analysis predicted an effective area between 1800 cm{sup 2} and 2500 cm{sup 2}. The multiplicity mode was found to be sensitive to the incident neutron angular distribution.

  7. 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.

  8. Neutron intensity of fast reactor spent fuel

    Energy Technology Data Exchange (ETDEWEB)

    Takamatsu, Misao; Aoyama, Takafumi [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center

    1998-03-01

    Neutron intensity of spent fuel of the JOYO Mk-II core with a burnup of 62,500 MWd/t and cooling time of 5.2 years was measured at the spent fuel storage pond. The measured data were compared with the calculated values based on the JOYO core management code system `MAGI`, and the average C/E approximately 1.2 was obtained. It was found that the axial neutron intensity didn`t simply follow the burnup distribution, and the neutron intensity was locally increased at the bottom end of the fuel region due to an accumulation of {sup 244}Cm. (author)

  9. Fast-neutron scattering from elemental cadmium

    International Nuclear Information System (INIS)

    Smith, A.B.; Guenther, P.T.

    1982-07-01

    Neutron differential-elastic-scattering cross sections of elemental cadmium are measured from approx. = 1.5 to 4.0 MeV at incident-neutron energy intervals of 50 to 200 keV and at 10 to 20 scattering angles distributed between approx. = 20 and 160 degrees. Concurrently, lumped-level neutron inelastic-excitation cross sections are measured. The experimental results are used to deduce parameters of an optical-statistical model that is descriptive of the observables and are compared with corresponding quantities given in ENDF/B-V

  10. Preliminary examination of the applicability of imaging plates to fast neutron radiography

    International Nuclear Information System (INIS)

    Matsubayashi, Masahito; Hibiki, Takashi; Mishima, Kaichiro; Yoshii, Koji; Okamoto, Koji

    2001-01-01

    Fast neutron radiography is an attractive non-destructive inspection technique because of the excellent penetration characteristics of fast neutrons in matter. However, the difficulty of detecting fast neutrons reduces this attractive feature. As an experiment to overcome the difficulty, imaging plates were applied to fast neutron radiography. A simple combination of two sheets of imaging plates and a sheet of polyethylene as a proton emitter was examined with the (fast neutron, thermal neutron and gamma ray) FTG discriminator proposed by Yoneda et al. . The experimental results showed that the method could be applicable to fast neutron radiography with effective discrimination of γ-rays

  11. Scattering of fast neutrons from elemental molybdenum

    International Nuclear Information System (INIS)

    Smith, A.B.; Guenther, P.T.

    1982-11-01

    Differential broad-resolution neutron-scattering cross sections of elemental molybdenum were measured at 10 to 20 scattering angles distributed between 20 and 160 degrees and at incident-neutron energy intervals of approx. = 50 to 200 keV from 1.5 to 4.0 MeV. Elastically-scattered neutrons were fully resolved from inelastic events. Lumped-level inelastic-neutron-scattering cross sections were determined corresponding to observed excitation energies of; 789 +- 23, 195 +- 23, 1500 +- 34, 1617 +- 12, 1787, 1874, 1991, 2063 +- 24, 2296, 2569 and 2802 keV. An optical-statistical model was deduced from the measured elastic-scattering results. The experimental values were compared with the respective quantities given in ENDF/B-V

  12. Dosimetry intercomparisons between fast neutron radiotherapy facilities

    International Nuclear Information System (INIS)

    Almond, P.R.; Smith, A.R.; Smathers, J.B.; Otte, V.A.

    1975-01-01

    Neutron dosimetry intercomparisons have been made between M.D. Anderson Hospital and Tumor Institute, Naval Research Laboratory, University of Washington Hospital, and Hammersmith Hospital. The parameters that are measured during these visits are: tissue kerma in air, tissue dose at depth of dose maximum, depth dose, beam profiles, neutron/gamma ratios and photon calibrations of ionization chambers. A preliminary report of these intercomparisons will be given including a comparison of the calculation and statement of tumor doses for each institution

  13. Fast neutron response of coumarin in water and heavy water

    International Nuclear Information System (INIS)

    Krishnan, D.; Kher, R.K.; Gopakumar, K.; Bhandari, N.S.

    1979-01-01

    Response of coumarin in aqueous solution has been studied earlier for gamma rays and fast neutrons by fluorescence measurement. For further fast neutron studies, two systems viz coumarin in H 2 0 and coumarin in D 2 0, were irradiated with fast neutrons in SNIF facility in the swimming pool type APSARA reactor at Trombay. Neutron fluence was estimated by measuring induced activity in sulphur pellet and associated gamma radiation was estimated using CaS0 4 :Dy TLD powder. The KERMA values were calculated for H 2 0 and D 2 0, assuming modified fission spectrum for fast neutron in SNIF position, and they were in the ratio of 2:1. Response of a chemical dosimetric system is expected to be proportional to the absorbed dose in the respective system for the same neutron fluence. This was experimentally found to be the case for coumarin in H 2 0 or D 2 0. These results are likely to be true in general for any aqueous chemical system. The limitations of using such a dual system for dosimetry in a mixed field is discussed. (author)

  14. Experimental Study of Fast Neutron Irradiation on Si Transistor

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Sung Ho; Sun, Gwang Min; Baek, Ha ni; Jin, Seong Bok; Hoang, Sy Minh Tuan [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    Bipolar junction transistors (BJTs) are applied in many industrial fields. BJT is a three-terminal device with an important feature in that the current through two terminals can be controlled by small changes we make in the current or voltage at the third terminal. This control feature allows us to amplify small AC signals or to switch the device from an on state and off state and back. These two operations, amplification and switching, are the basis of a host of electronic functions. This study will investigate the electrical characteristics of a p-n-p BJT, such as the base current and collector current for fast neutron irradiation. Fast neutron irradiation can cause displacement damage in the Si bulk. In this paper, the electrical characteristics of a p-n-p BJT such as a base current and collector current are investigated for fast neutron irradiation. The experimental results show that the base current is increased and the collector current is decreased after fast neutron irradiation. These results indicate that the displacement damage caused by fast neutron irradiation increases the recombination rate of minority carriers and resistors.

  15. Fast neutron fields imaging with a CCD-based luminescent detector

    CERN Document Server

    Mikerov, V

    1999-01-01

    The paper considers some questions concerned with the development of an imaging system based on a CCD-detector for visualising fast neutron fields. From those the most important are: development of fast neutron screens, detector resistance to irradiation fields, and feasibility of fast neutron radiography and tomography at various neutron sources.

  16. Beam profiles for fast neutrons; and reply

    International Nuclear Information System (INIS)

    Bewley, D.K.; Parnell, C.J.; Bloch, P.

    1976-01-01

    The authors express surprise that Bloch et al. (Bloch, P.H., Hendry, G.O., Hilton, J.L., Quam, W.M., Reinhard, D.K., and Wilson, C., 1976, Phys. Med. Biol., Vol. 21, 450) justified a target size of 5.5 x 5.5 cm in a neutron generator by comparison with the profile given by a 2.5 MV X-ray generator. The penumbral width of this new neutron generator is more than twice that of a modern megavoltage X-ray machine, and larger than those of beams from standard 60 Co units, or of the Hammersmith Hospital cyclotron beam. The large target size of the neutron generator may have to be accepted as a necessary evil, but should not be considered satisfactory. In reply, one of the authors of the original note presents the results of calculations of beam profiles for 14 MeV neutron beams in a tissue-equivalent phantom, and suggests that the broader profiles are principally caused by the larger probability of side scatter, not by source size. The most fruitful approach to sharpening the neutron beam profile would seem to be to design a field flattening filter to increase relative dose near the edge inside the geometrically defined field. Calculations indicating that Bewley and Parnell have underestimated the penumbral widths of 60 Co beams are also presented. (U.K.)

  17. Digital Acquisition Development for Fast Neutron Detectors

    Science.gov (United States)

    Seagren, T.; Mosby, S.; Mona Collaboration; Lansce P-27 Team

    2015-10-01

    The use of the Modular Neutron Array (MoNA) at FRIB requires a thorough understanding of how neutrons propagate through the array. This leads to the increasing importance of accuracy in detector response simulations, particularly in the case of FRIB's higher beam energies. An upcoming experiment at the LANSCE facility at Los Alamos National Lab will benchmark neutron propagation through the MoNA array and provide a more complete validation of the simulation software. LANSCE also hosts the Chi-Nu experiment, which seeks to measure fission output neutrons using the high-intensity neutron beams there. In both experiments, the instantaneous rate on the detectors involved is expected to be very high, due to the LANSCE/WNR beam structure. Therefore, waveform digitizers with on-board processing are required in order for the experiments to succeed. These digitizers provide on-board timing algorithms using FPGA firmware, and several tests were preformed in order to determine what the optimal timing filter settings were for a variety of detectors, including the plastic and liquid scintillators to be used in MoNA and Chi-Nu respectively. This work will inform the execution of the MoNA and Chi-Nu experiments at LANSCE. The details of the methods used and results will be presented. Supported by funding through Los Alamos National Lab and NSF Grant PHY-1506402.

  18. A new fast-neutron source for radiobiological research

    CERN Document Server

    Wolber, G; Krauss, O; Maier-Borst, W

    1997-01-01

    A biomedical cyclotron facility primarily dedicated to radionuclide production has been extended by the addition of an experimental fast-neutron source for radiobiological and biophysical studies. Several beams of fast-neutrons with different average energies and LET distributions can now be provided. The neutrons are produced by bombarding beryllium targets with 8-32 MeV protons or 8.7-15 MeV deuterons from our K 32 negative-ion cyclotron. Average neutron energies range from approximately 4 to 15 MeV. doses at maximum build-up vary from 0.24 to 1.85 cGy mu A sup - sup 1 min sup - sup 1 at 1 m SD, i.e. approximately 55 cGy min sup - sup 1 at 30 mu A of proton current at maximum energy. The design of the facility and some dosimetric results are presented. (author)

  19. Minimum detectable dose equivalant of NTA film for fast neutron

    International Nuclear Information System (INIS)

    Ito, Masashi; Kumazawa, Shigeru; Nishi, Tatsuo; Numakunai, Takao

    1982-01-01

    A method has been studied of estimating the minimum detectable dose equivalent of fast neutrons for measurement of recoil proton tracks in NTA film. Poisson distribution was applied in estimation of the minimum detectable number of tracks. Factors such as sensitivity of the film for fast neutrons, energy dependency of the film response, and latent image fading of the tracks were taken into consideration in the estimation. The minimum detectable dose equivalent was affected by fluctuation in the number of tracks due to background radiation and degree of the affection depended on the measured area. The minimum detectable dose equivalent decreased with increasing the measuring area of background radiation even if the measuring area of neutron-irradiated film was small. The relation between the minimum detectable dose equivalent and the measuring area of neutron-irradiated film was obtained considering the effect of latent image fading. (author)

  20. Real‑time, fast neutron detection for stimulated safeguards assay

    International Nuclear Information System (INIS)

    Joyce, Malcolm J.; Adamczyk, Justyna; Plenteda, Romano; Aspinall, Michael D.; Cave, Francis D.

    2015-01-01

    The advent of low‑hazard organic liquid scintillation detectors and real‑time pulse‑shape discrimination (PSD) processing has suggested a variety of modalities by which fast neutrons, as opposed to neutrons moderated prior to detection, can be used directly to benefit safeguards needs. In this paper we describe a development of a fast‑neutron based safeguards assay system designed for the assessment of 235 U content in fresh fuel. The system benefits from real‑time pulse‑shape discrimination processing and auto‑calibration of the detector system parameters to ensure a rapid and effective set‑up protocol. These requirements are essential in optimising the speed and limit of detection of the fast neutron technique, whilst minimising the intervention needed to perform the assay.

  1. Fast neutron scattering near shell closures: Scandium

    International Nuclear Information System (INIS)

    Smith, A.B.; Guenther, P.T.

    1992-08-01

    Neutron differential elastic- and inelastic-scattering cross sections are measured from ∼ 1.5 to 10 MeV with sufficient detail to define the energy-averaged behavior of the scattering processes. Neutrons corresponding to excitations of 465 ± 23, 737 ± 20, 1017 ± 34, 1251 ± 20, 1432 ± 23 and 1692 ± 25 keV are observed. It is shown that the observables, including the absorption cross section, are reasonably described with a conventional optical-statistical model having energy-dependent geometric parameters. These energy dependencies are alleviated when the model is extended to include the contributions of the dispersion relationship. The model parameters are conventional, with no indication of anomalous behavior of the neutron interaction with 45 Sc, five nucleons from the doubly closed shell at 40 Ca

  2. Transportable, Low-Dose Active Fast-Neutron Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Mihalczo, John T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wright, Michael C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McConchie, Seth M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Archer, Daniel E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Palles, Blake A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-08-01

    This document contains a description of the method of transportable, low-dose active fast-neutron imaging as developed by ORNL. The discussion begins with the technique and instrumentation and continues with the image reconstruction and analysis. The analysis discussion includes an example of how a gap smaller than the neutron production spot size and detector size can be detected and characterized depending upon the measurement time.

  3. Present status of fast neutron therapy for the malignant tumors

    International Nuclear Information System (INIS)

    Tsunemoto, Hiroshi; Morita, Shinroku; Honke, Yoshifumi

    1980-01-01

    Fast neutron therapy has been applied to the treatment of cancer of the head and the neck, prostatic cancer, osteosarcoma, and malignant melanoma, and the basic treatment schedule for this therapy for them has been almost established. The effectiveness of this therapy for squamous cell carcinoma of the uterus will be established by the results of future clinical application of this therapy. It is expected that postoperative irradiation of fast neutron will decrease local recurrence of adenocarcinoma of the uterus. Treatment schedule for fast neutron therapy for esophageal cancer and lung cancer must be established, and moreover, it is necessary to apply this therapy to the treatment of gastric and pancreatic cancer. (Tsunoda, M.)

  4. Response of six neutron survey meters in mixed fields of fast and thermal neutrons.

    Science.gov (United States)

    Kim, S I; Kim, B H; Chang, I; Lee, J I; Kim, J L; Pradhan, A S

    2013-10-01

    Calibration neutron fields have been developed at KAERI (Korea Atomic Energy Research Institute) to study the responses of commonly used neutron survey meters in the presence of fast neutrons of energy around 10 MeV. The neutron fields were produced by using neutrons from the (241)Am-Be sources held in a graphite pile and a DT neutron generator. The spectral details and the ambient dose equivalent rates of the calibration fields were established, and the responses of six neutron survey meters were evaluated. Four single-moderator-based survey meters exhibited an under-responses ranging from ∼9 to 55 %. DINEUTRUN, commonly used in fields around nuclear reactors, exhibited an over-response by a factor of three in the thermal neutron field and an under-response of ∼85 % in the mixed fields. REM-500 (tissue-equivalent proportional counter) exhibited a response close to 1.0 in the fast neutron fields and an under-response of ∼50 % in the thermal neutron field.

  5. Fast Neutron Dose Distribution in a Linac Radiotherapy Facility

    International Nuclear Information System (INIS)

    Al-Othmany, D.Sh.; Abdul-Majid, S.; Kadi, M.W.

    2011-01-01

    CR-39 plastic detectors were used for fast neutron dose mapping in the radiotherapy facility at King AbdulAziz University Hospital (KAUH). Detectors were calibrated using a 252 Cf neutron source and a neutron dosimeter. After exposure chemical etching was performed using 6N NaOH solution at 70 degree C. Tracks were counted using an optical microscope and the number of tracks/cm 2 was converted to a neutron dose. 15 track detectors were distributed inside and outside the therapy room and were left for 32 days. The average neutron doses were 142.3 mSv on the accelerator head, 28.5 mSv on inside walls, 1.4 mSv beyond the beam shield, and 1 mSv in the control room

  6. An empirical formula for scattered neutron components in fast neutron radiography

    International Nuclear Information System (INIS)

    Dou Haifeng; Tang Bin

    2011-01-01

    Scattering neutrons are one of the key factors that may affect the images of fast neutron radiography. In this paper, a mathematical model for scattered neutrons is developed on a cylinder sample, and an empirical formula for scattered neutrons is obtained. According to the results given by Monte Carlo methods, the parameters in the empirical formula are obtained with curve fitting, which confirms the logicality of the empirical formula. The curve-fitted parameters of common materials such as 6 LiD are given. (authors)

  7. Selective assessment of the fast neutron component in mixed neutron-gamma field using TLD activation

    Energy Technology Data Exchange (ETDEWEB)

    Ranogajec-Komor, M. E-mail: marika@rudjer.irb.hr; Miljanic, S.; Blagus, S.; Knezevic, Z.Z.; Osvay, M

    2003-06-01

    Selective determination of the fast neutron component in a mixed radiation field by the TL dosimetry was studied. TL responses due to the induced radioactivity in Al{sub 2}O{sub 3}:C dosimeters via the {sup 27}Al(n,{alpha}){sup 24}Na reaction were used to measure the neutron part in a mixed 14.5 MeV neutron and gamma irradiation field. The lowest detectable neutron dose was found to be in order of 10 mSv of personal dose equivalent for Al{sub 2}O{sub 3}:C.

  8. Constraints on Vesta's elemental composition: Fast neutron measurements by Dawn's gamma ray and neutron detector

    Science.gov (United States)

    Lawrence, David J; Peplowski, Patrick N; Prettyman, Thomas H; Feldman, William C; Bazell, David; Mittlefehldt, David W; Reedy, Robert C; Yamashita, Naoyuki

    2013-01-01

    Surface composition information from Vesta is reported using fast neutron data collected by the gamma ray and neutron detector on the Dawn spacecraft. After correcting for variations due to hydrogen, fast neutrons show a compositional dynamic range and spatial variability that is consistent with variations in average atomic mass from howardite, eucrite, and diogenite (HED) meteorites. These data provide additional compositional evidence that Vesta is the parent body to HED meteorites. A subset of fast neutron data having lower statistical precision show spatial variations that are consistent with a 400 ppm variability in hydrogen concentrations across Vesta and supports the idea that Vesta's hydrogen is due to long-term delivery of carbonaceous chondrite material. PMID:26074718

  9. Transmutation of Americium in Fast Neutron Facilities

    OpenAIRE

    Zhang, Youpeng

    2011-01-01

    In this thesis, the feasibility to use a medium sized sodium cooled fast reactor fully loaded with MOX fuel for efficient transmutation of americium is investigated by simulating the safety performance of a BN600-type fast reactor loaded with different fractions of americium in the fuel, using the safety parameters obtained with the SERPENT Monte Carlo code. The focus is on americium mainly due to its long-term contribution to the radiotoxicity of spent nuclear fuel and its deterioration on c...

  10. Geochemistry at 4 Vesta: Observations Using Fast Neutrons

    Science.gov (United States)

    Lawrence, David J.; Prettyman, Thomas H.; Feldman, William C.; Bazell, David; Mittlefehldt, David W.; Peplowski, Patrick N.; Reedy, Robert C.

    2012-01-01

    Dawn is currently in orbit around the asteroid 4 Vesta, and one of the major objectives of the mission is to probe the relationship of Vesta to the Howardite, Eucrite, and Diogenite (HED) meteorites. As Vesta is an example of a differentiated planetary embryo, Dawn will also provide fundamental information about planetary evolution in the early solar system [1]. To help accomplish this overall goal, the Dawn spacecraft carries the Gamma-Ray and Neutron Detector (GRaND). GRaND uses planetary gamma-ray and neutron spectroscopy to measure the surface elemental composition of Vesta and will provide information that is unique and complementary to that provided by the other Dawn instruments and investigations. Gamma-ray and neutron spectroscopy is a standard technique for measuring planetary compositions [2], having successfully made measurements at near-Earth asteroids, the Moon, Mars, Mercury and now Vesta. GRaND has made the first measurements of the neutron spectrum from any asteroid (previous asteroid measurements were only made with gamma-rays). Dawn has been collecting data at Vesta since July 2011. The prime data collection period for GRaND is the Low-Altitude Mapping Orbit (LAMO), which started on 12 December 2011 and will last through spring 2012. During LAMO, the Dawn spacecraft orbits at an average altitude of 210 km above the surface of Vesta, which allows good neutron and gamma-ray signals to be detected from Vesta. A description of the overall goals of GRaND and a summary of the initial findings are given elsewhere [3,4]. The subject of this study is to present the information that will be returned from GRaND using fast neutron measurements. Here, we discuss what fast neutrons can reveal about Vesta s surface composition, how such data can address Dawn science goals, and describe fast neutron measurements made in the early portion of the Vesta LAMO phase.

  11. Direct Fast-Neutron Detection: A Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    AJ Peurrung; DC Stromswold; PL Reeder; RR Hansen

    1998-10-18

    It is widely acknowledged that Mure neutron-detection technologies will need to offer increased performance at lower cost. One clear route toward these goals is rapid and direct detection of fast neutrons prior to moderation. This report describes progress to date in an effort to achieve such neutron detection via proton recoil within plastic scintillator. Since recording proton-recoil events is of little practical use without a means to discriminate effectively against gamma-ray interactions, the present effort is concentrated on demonstrating a method that distinguishes between pulse types. The proposed method exploits the substantial difference in the speed of fission neutrons and gamma-ray photons. Should this effort ultimately prove successful, the resulting. technology would make a valuable contribution toward meeting the neutron-detection needs of the next century. This report describes the detailed investigations that have been part of Pacific Northwest National Laborato@s efforts to demonstrate direct fast-neutron detection in the laboratory. Our initial approach used a single, solid piece of scintillator along with the electronics needed for pulse-type differentiation. Work to date has led to the conclusion that faster scintillator and/or faster electronics will be necessary before satisfactory gamma-ray discrimination is achieved with this approach. Acquisition and testing of both faster scintillator and faster electronics are currently in progress. The "advanced" approach to direct fast-neutron detection uses a scintillating assembly with an overall density that is lower than that of ordinary plastic scintillator. The lower average density leads to longer interaction times for both neutrons and gamma rays, allowing easier discrimination. The modeling, optimization, and design of detection systems using this approach are described in detail.

  12. FAST FOSSIL ROTATION OF NEUTRON STAR CORES

    International Nuclear Information System (INIS)

    Melatos, A.

    2012-01-01

    It is argued that the superfluid core of a neutron star super-rotates relative to the crust, because stratification prevents the core from responding to the electromagnetic braking torque, until the relevant dissipative (viscous or Eddington-Sweet) timescale, which can exceed ∼10 3 yr and is much longer than the Ekman timescale, has elapsed. Hence, in some young pulsars, the rotation of the core today is a fossil record of its rotation at birth, provided that magnetic crust-core coupling is inhibited, e.g., by buoyancy, field-line topology, or the presence of uncondensed neutral components in the superfluid. Persistent core super-rotation alters our picture of neutron stars in several ways, allowing for magnetic field generation by ongoing dynamo action and enhanced gravitational wave emission from hydrodynamic instabilities.

  13. The interaction of fast neutrons with hafnium

    International Nuclear Information System (INIS)

    Smith, A.B.

    2002-01-01

    Elemental hafnium neutron total cross sections are measured from ∼0.75 to 4.5 MeV in steps of ∼40 keV. Differential neutron elastic-scattering cross sections are measured from ∼4.5 to 10.0 MeV in ∼0.5 MeV steps and at 40 scattering angles distributed between ∼17 and 160 deg. These data are combined with those found in the literature to construct a comprehensive experimental data base which is interpreted in terms of coupled-channels models. Physical characteristics of the resulting potentials are discussed. Comparisons are made with ENDF/B-6 (MAT 7200). A detailed report of this work is given by Smith (Smith, A., 2001. Argonne National Laboratory Report ANL/NDM-153)

  14. He-4 fast neutron detectors in nuclear security applications

    International Nuclear Information System (INIS)

    Murer, D. E.

    2014-01-01

    This work presents studies of 4 He fast neutron detectors for nuclear security applications. Such devices are high pressure gas scintillation detectors, sensitive to neutrons in the energy range of fission sources. First, an introduction to the scope of the intended application is given. This is followed by a description of all components relevant to the operation of the detector. The next chapter presents studies of various characteristics of the neutron detector, among them properties of its scintillation response, differences between neutron and gamma interactions and effects of the light collection process. The results of the detector characterization are used to develop neutron gamma discrimination methods. These methods are put to the test using measurements with a high gamma flux, and the results are compared to performance requirements of Radiation Portal Monitors. Background neutron measurements are presented next. Measured neutron rates are compared to values published in scientific literature. The fluctuation of the background count rate was studied, and the contribution of muons evaluated. Two applications of the detectors in the field of nuclear security are discussed in the last two chapters. The first one is a novel method to measure the plutonium mass in a container filled with Mixed Oxide Fuel. The last chapter presents the development of a Radiation Portal Monitor which, in addition to neutron and gamma counting, exploits time correlation to detect threats such as plutonium and 60 Co. (author)

  15. Fast ultrasonic visualisation under sodium. Application to the fast neutron reactors

    International Nuclear Information System (INIS)

    Imbert, Ch.

    1997-01-01

    The fast ultrasonic visualization under sodium is in the programme of research and development on the inspection inside the fast neutron reactors. This work is about the development of a such system of fast ultrasonic imaging under sodium, in order to improve the existing visualization systems. This system is based on the principle of orthogonal imaging, it uses two linear antennas with an important dephasing having 128 piezo-composite elements of central frequency equal to 1.6 MHz. (N.C.)

  16. Fast Neutron Emission Tomography of Used Nuclear Fuel Assemblies

    Science.gov (United States)

    Hausladen, Paul; Iyengar, Anagha; Fabris, Lorenzo; Yang, Jinan; Hu, Jianwei; Blackston, Matthew

    2017-09-01

    Oak Ridge National Laboratory is developing a new capability to perform passive fast neutron emission tomography of spent nuclear fuel assemblies for the purpose of verifying their integrity for international safeguards applications. Most of the world's plutonium is contained in spent nuclear fuel, so it is desirable to detect the diversion of irradiated fuel rods from an assembly prior to its transfer to ``difficult to access'' storage, such as a dry cask or permanent repository, where re-verification is practically impossible. Nuclear fuel assemblies typically consist of an array of fuel rods that, depending on exposure in the reactor and consequent ingrowth of 244Cm, are spontaneous sources of as many as 109 neutrons s-1. Neutron emission tomography uses collimation to isolate neutron activity along ``lines of response'' through the assembly and, by combining many collimated views through the object, mathematically extracts the neutron emission from each fuel rod. This technique, by combining the use of fast neutrons -which can penetrate the entire fuel assembly -and computed tomography, is capable of detecting vacancies or substitutions of individual fuel rods. This paper will report on the physics design and component testing of the imaging system. This material is based upon work supported by the U.S. Department of Energy, Office of Defense Nuclear Nonproliferation Research and Development within the National Nuclear Security Administration, under Contract Number DE-AC05-00OR22725.

  17. Radiation-induced modification of titanium nickelide with fast neutrons

    Science.gov (United States)

    Parkhomenko, V. D.; Dubinin, S. F.

    2012-07-01

    We present a review of the investigations of the effect of fast neutrons on the structure and properties of titanium nickelide that were performed by the authors on an IVV-2M atomic reactor (Zarechnyi). It has been established that at small fluences of fast neutrons atomic disordering of crystals is observed; as the fluence increases, the material becomes partially amorphized; and at fluences higher than 1 × 1020 cm-2, the material transforms completely into the amorphous state. It has been shown that the amorphous state produced by neutron irradiation differs substantially from the amorphous state of materials obtained by conventional methods. In particular, if a single-crystal specimen is subjected to "neutron" amorphization (most of the investigations were carried out using single crystals), after annealing of radiation-induced defects the single crystal is restored with the initial orientation and perfection. The structural studies were conducted by the methods of neutron and X-ray diffraction. Based on these studies, as well as on the results of small-angle neutron scattering and dilatometric and resistivity measurements, the "defect" state of irradiated materials has been examined in detail. The radiation resistance of titanium nickelide has been estimated.

  18. Fast neutron detection with 6Li-loaded liquid scintillator

    Science.gov (United States)

    Fisher, B. M.; Abdurashitov, J. N.; Coakley, K. J.; Gavrin, V. N.; Gilliam, D. M.; Nico, J. S.; Shikhin, A. A.; Thompson, A. K.; Vecchia, D. F.; Yants, V. E.

    2011-08-01

    We report on the development of a fast neutron detector using a liquid scintillator doped with enriched 6Li. The lithium was introduced in the form of an aqueous LiCl micro-emulsion with a di-isopropylnaphthalene-based liquid scintillator. A 6Li concentration of 0.15% by weight was obtained. A 125 mL glass cell was filled with the scintillator and irradiated with fission-source neutrons. Fast neutrons may produce recoil protons in the scintillator, and those neutrons that thermalize within the detector volume can be captured on the 6Li. The energy of the neutron may be determined by the light output from recoiling protons, and the capture of the delayed thermal neutron reduces background events. In this paper, we discuss the development of this 6Li-loaded liquid scintillator, demonstrate the operation of it in a detector, and compare its efficiency and capture lifetime with Monte Carlo simulations. Data from a boron-loaded plastic scintillator were acquired for comparison. We also present a pulse-shape discrimination method for differentiating between electronic and nuclear recoil events based on the Matusita distance between a normalized observed waveform and nuclear and electronic recoil template waveforms. The details of the measurements are discussed along with specifics of the data analysis and its comparison with the Monte Carlo simulation.

  19. Fast neutron sensitivity of dry and germinating tomato seeds

    NARCIS (Netherlands)

    Contant, R.B.

    1970-01-01

    A study was made of changes in fast neutron effectiveness during the hydration and germination of tomato seeds. The main findings and conclusions are the following,

    Section 3.6

    Samples of unirradiated seeds and their constituent parts (seedcoat+endosperm and embryo) were taken at short

  20. Semiclassical model of cross section for fast neutrons

    International Nuclear Information System (INIS)

    Rosato, A.; D'Oliveira, A.A.

    1977-01-01

    A study for main aspects of fast neutron scattering is presented and, a semiclassical approximation applying to several pratic cases is described. The obtained results are compared with experimental data for deformed nuclei, and, with theoretical data based on optical model without treatment of deformations. (M.C.K.) [pt

  1. Nuclear structure effects on calculated fast neutron reaction cross sections

    International Nuclear Information System (INIS)

    Avrigeanu, V.

    1992-01-01

    The importance of accurate low-lying level schemes for reaction cross section calculation and need for microscopically calculated levels are proved with reference to fast neutron induced reactions in the A = 50 atomic mass range. The uses of the discrete levels both for normalization of phenomenological level density approaches and within Hauser-Feshbach calculations are discussed in this respect. (Author)

  2. Fast neutron induced increase of flowering in portulaca grandiflora linn

    International Nuclear Information System (INIS)

    Abraham, V.; Desai, B.M.

    1975-01-01

    Unbranched cuttings were exposed to fast neutron doses of 71-284 rads and planted along with unirradiated controls. There was a significant increase in the numbers of flowers in the treated populations due to the increased production of primary and secondary branches. (MG) [de

  3. Design of fast neutron channels for topaz irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, Nader M.A., E-mail: mnader73@yahoo.com; Gaheen, M.A.

    2016-12-15

    Highlights: • This work aims to design fast neutron irradiation channels for topaz irradiation. • The irradiation boxes are shielded using a martial contains B-10. • Calculations of neutron flux and heat generation were carried out using the MCNPX code and the effect on the reactor reactivity has been considered. • Experimentally, the worker exposure has been reduced to less than one-tenth and a decrease of 12 months in the release time of the treated topaz has been achieved. - Abstract: The aim of this work is to design fast neutron irradiation channels for topaz irradiation at Egypt Second Research Reactor (ETRR-2) by shielding the aluminum boxes, used for topaz irradiation, with B{sub 4}C (boron carbide) or manufacturing the irradiation boxes from aluminum contains boron. This in turn suppresses the thermal neutrons inside the box resulting in reduction of the residual radioactivity in topaz which decreases the worker exposure and release time. Simulation of the fast irradiation channels using the code: MCNPX showed that the thermal neutron component can be suppressed to less than one-tenth. ETRR-2 has many irradiation positions. The fast neutron flux distributions along the irradiation positions and the required irradiation times were calculated. The limiting conditions for safe operation of movable experiments are considered in the selection of the irradiation positions. That is the change in reactor reactivity due to the B-10 shield is below the reactivity limit for safe irradiation experiments. Heat generated during irradiation in topaz and in the material that contains boron was considered, as well. Experimentally, the worker exposure has been reduced to less than one-tenth and a decrease of 12 months in the release time of the irradiated topaz has been achieved. Also adequate cooling of the shielded box during irradiation has been demonstrated.

  4. Fast neutron inelastic scattering from nuclei

    International Nuclear Information System (INIS)

    Lachkar, J.

    1978-01-01

    The need for accurate values of inelastic scattering cross sections appears when the requests for neutron data for reactors and other applied purposes are considered. These requests are partly related to values for spherical nuclei, well studied over many years. These studies were extensively considered in two review papers presented, in 1976, at the International Conference on the Interactions of Neutrons with nuclei. Other requests are related to vibrational and rotational nuclei, and relevant studies have been recently performed. The quality of these investigations and the large number of recent results have lead to concentration on them as the topic of the present review. The constant improvements of the experimental techniques permits precise measurements of inelastic scattering cross sections to the first excited levels over a range of incident energies, such that different reactions mechanisms are predominant in different parts of that range of energies. Quadrupole, hexadecapole and octupole deformation parameters of the target nuclei can be deduced from the data using phenomenological models. The successful application of the analysis over the range of energies leads to the conclusion that reliable information on the shape of the nuclei has been derived. The validity of the various models, which include direct interaction and compound nucleus reaction mechanisms, is discussed in connection with analyses of recent experiments. (author) [fr

  5. Development of plutonium: Fast Neutrons Reactors option

    International Nuclear Information System (INIS)

    Etudes de la Vallee du Rhone, 30 - Marcoule (France). Dept. de la Centrale Phenix)" data-affiliation=" (CEA Centre dEtudes de la Vallee du Rhone, 30 - Marcoule (France). Dept. de la Centrale Phenix)" >Elie, X.

    1994-01-01

    Phenix reactor is shortly described with combustible assembly with some operational data. 'CAPRA'(Plutonium Enhance Consumption in Fast Reactors) is an R and D program for the development of an optimized combustible for fast reactors for burning more plutonium. Three ways are tested: a 45% Pu concentration in an oxide fuel keeping actual fabrication and reprocessing options giving a 80 kg/TWh Pu consumption, a fuel without U 238 but with a W or a Mo matrix with problems of reprocessing and core reactivity giving a 110 kg/TWh Pu consumption, and a nitride fuel with an up to 65% Pu concentration giving a 90 to 100 kg/TWh Pu consumption. (A.B.)

  6. System and plastic scintillator for discrimination of thermal neutron, fast neutron, and gamma radiation

    Science.gov (United States)

    Zaitseva, Natalia P.; Carman, M. Leslie; Faust, Michelle A.; Glenn, Andrew M.; Martinez, H. Paul; Pawelczak, Iwona A.; Payne, Stephen A.

    2017-05-16

    A scintillator material according to one embodiment includes a polymer matrix; a primary dye in the polymer matrix, the primary dye being a fluorescent dye, the primary dye being present in an amount of 3 wt % or more; and at least one component in the polymer matrix, the component being selected from a group consisting of B, Li, Gd, a B-containing compound, a Li-containing compound and a Gd-containing compound, wherein the scintillator material exhibits an optical response signature for thermal neutrons that is different than an optical response signature for fast neutrons and gamma rays. A system according to one embodiment includes a scintillator material as disclosed herein and a photodetector for detecting the response of the material to fast neutron, thermal neutron and gamma ray irradiation.

  7. A measurement of the response to fast neutrons of several materials dosemeters

    International Nuclear Information System (INIS)

    Jones, L.T.; Kitching, S.J.; Lewis, T.A.; Playle, T.S.

    1986-07-01

    The response to fast neutrons was measured for three types of materials testing dosemeters: fast neutron dosimetry silicon diodes; beryllia, alumina and calcium fluoride TLDs; graphite walled ionisation chambers. The calibrations were made using a 3MW positive ion accelerator. The arrangement of the target, beam monitor and devices is described, and the measured fast neutron sensitivities are presented. (UK)

  8. Modification of the University of Washington Neutron Radiotherapy Facility for optimization of neutron capture enhanced fast-neutron therapy

    International Nuclear Information System (INIS)

    Nigg, David W.; Wemple, Charles A.; Risler, Ruedi; Hartwell, John K.; Harker, Yale D.; Laramore, George E.

    2000-01-01

    A modified neutron production target assembly has been developed to provide improved performance of the proton-cyclotron-based neutron radiotherapy facility at the University of Washington for applications involving neutron capture enhanced fast-neutron therapy. The new target produces a neutron beam that yields essentially the same fast-neutron physical depth-dose distribution as is produced by the current UW clinical system, but that also has an increased fraction of BNCT enhancement relative to the total therapeutic dose. The modified target is composed of a 5-millimeter layer of beryllium, followed by a 2.5-millimeter layer of tungsten, with a water-cooled copper backing. Measurements of the free-field neutron spectrum of the beam produced by the new target were performed using activation foils with a direct spectral unfolding technique. Water phantom measurements were performed using a tissue-equivalent ion chamber to characterize the fast-neutron depth-dose curve and sodium activation in soda-lime glass beads to characterize the thermal-neutron flux (and thus the expected neutron capture dose enhancement) as a function of depth. The results of the various measurements were quite consistent with expectations based on the design calculations for the modified target. The spectrum of the neutron beam produced by the new target features an enhanced low-energy flux component relative to the spectrum of the beam produced by the standard UW target. However, it has essentially the same high-energy neutron flux, with a reduced flux component in the mid-range of the energy spectrum. As a result, the measured physical depth-dose curve in a large water phantom has the same shape compared to the case of the standard UW clinical beam, but approximately twice the level of BNCT enhancement per unit background neutron dose at depths of clinical interest. In-vivo clinical testing of BNCT-enhanced fast-neutron therapy for canine lung tumors using the new beam was recently

  9. EDF research on fast neutron reactors

    International Nuclear Information System (INIS)

    In order to make possible the calculation of the temperatures of the sodium, of the sheath and of the fuel in fast reactor assemblies, taking into account the mixing phenomena induced by the helicoidal wires, two design codes have been developed. Those codes have then been adapted for their integration in the Superalcyon system. This system shall constitute the reference tool for the development of those codes that shall manage Phenix, and other reactors of the family. Cooling accidents, thermohydraulic studies, and steam generator studies are also in progress

  10. Development of a Boron Neutron Capture Enhanced Fast Neutron Therapy Beam

    Energy Technology Data Exchange (ETDEWEB)

    Sweezy, Jeremy Ed [Georgia Tech

    2002-01-01

    The combination of fast neutron therapy and boron neutron capture therapy is currently under investigation at several fast neutron therapy centers worldwide. This treatment method, termed boron neutron capture enhanced fast neutron therapy (BNCEFNT) utilizes a boron containing drug to selectively increase the dose to the target tumor. BNCEFNT may be useful in the treatment of some radioresistant brain tumors, such as glioblastoma multiforme. A neutron therapy beam for boron neutron capture enhanced fast neutron therapy has been developed for the existing Fermilab Neutron Therapy Facility. This beam produces a significant dose enhancement due to the the boron neutron capture reaction. The beam was developed by designing a filter and collimator system using the Monte Carlo radiation transport code, MCNPX. The MCNPX code was benchmarked against depth-dose measurements of the standard treatment beam. The new BNCEFNT beam is filtered with 18.3-cm of low carbon steel and is collimated with steel. Measurements of the dose enhancement of the new BNCEFNT beam were performed with paired tissue equivalent ion chambers. One of the ion chambers has boron incorporated in the wall of the chamber to measure the dose due to boron neutron capture. The measured boron dose enhancement of the BNCEFNT beam is (16.3 ± 2.6)% per 100-ppm 10B for a 20-cm diameter beam and (10.0 ± 1.6)% per 100-ppm 10B for a 10-cm diameter beam. The dose rate of the new beam is reduced to 4.4% of the dose rate of the standard treatment beam. xxi A conceptual design that overcomes the reduced dose rate is also presented. This design uses a tungsten collimator placed near the patient, with a 1.5-cm tungsten filter just upstream of the collimator. Using graphite moderation of neutrons around the patient a percent dose enhancement of 15% can be attained with good collimation, for field sizes as small as 5 × 5 cm2 , and without a reduction in dose rate.

  11. Inelastic scattering of fast neutrons from $^{56}$Fe

    CERN Document Server

    Beyer, R; Hannaske, R; Junghans, A R; Massarczyk, R; Anders, M; Bemmerer, D; Ferrari, A; Kögler, T; Röder, M; Schmidt, K; Wagner, A

    2014-01-01

    Inelastic scattering of fast neutrons from $^{56}$Fe was studied at the photoneutron source nELBE. The neutron energies were determined on the basis of a timeof- flight measurement. Gamma-ray spectra were measured with a high-purity germanium detector. The total scattering cross sections deduced from the present experiment in an energy range from 0.8 to 9.6 MeV agree within 15% with earlier data and with predictions of the statistical-reaction code Talys.

  12. Computer aided design of fast neutron therapy units

    International Nuclear Information System (INIS)

    Gileadi, A.E.; Gomberg, H.J.; Lampe, I.

    1980-01-01

    Conceptual design of a radiation-therapy unit using fusion neutrons is presently being considered by KMS Fusion, Inc. As part of this effort, a powerful and versatile computer code, TBEAM, has been developed which enables the user to determine physical characteristics of the fast neutron beam generated in the facility under consideration, using certain given design parameters of the facility as inputs. TBEAM uses the method of statistical sampling (Monte Carlo) to solve the space, time and energy dependent neutron transport equation relating to the conceptual design described by the user-supplied input parameters. The code traces the individual source neutrons as they propagate throughout the shield-collimator structure of the unit, and it keeps track of each interaction by type, position and energy. In its present version, TBEAM is applicable to homogeneous and laminated shields of spherical geometry, to collimator apertures of conical shape, and to neutrons emitted by point sources or such plate sources as are used in neutron generators of various types. TBEAM-generated results comparing the performance of point or plate sources in otherwise identical shield-collimator configurations are presented in numerical form. (H.K.)

  13. Design of a boron neutron capture enhanced fast neutron therapy assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhonglu [Georgia Inst. of Technology, Atlanta, GA (United States)

    2006-12-01

    The use of boron neutron capture to boost tumor dose in fast neutron therapy has been investigated at several fast neutron therapy centers worldwide. This treatment is termed boron neutron capture enhanced fast neutron therapy (BNCEFNT). It is a combination of boron neutron capture therapy (BNCT) and fast neutron therapy (FNT). It is believed that BNCEFNT may be useful in the treatment of some radioresistant brain tumors, such as glioblastoma multiform (GBM). A boron neutron capture enhanced fast neutron therapy assembly has been designed for the Fermilab Neutron Therapy Facility (NTF). This assembly uses a tungsten filter and collimator near the patient's head, with a graphite reflector surrounding the head to significantly increase the dose due to boron neutron capture reactions. The assembly was designed using Monte Carlo radiation transport code MCNP version 5 for a standard 20x20 cm2 treatment beam. The calculated boron dose enhancement at 5.7-cm depth in a water-filled head phantom in the assembly with a 5x5 cm2 collimation was 21.9% per 100-ppm 10B for a 5.0-cm tungsten filter and 29.8% for a 8.5-cm tungsten filter. The corresponding dose rate for the 5.0-cm and 8.5-cm thick filters were 0.221 and 0.127 Gy/min, respectively; about 48.5% and 27.9% of the dose rate of the standard 10x10 cm2 fast neutron treatment beam. To validate the design calculations, a simplified BNCEFNT assembly was built using four lead bricks to form a 5x5 cm2 collimator. Five 1.0-cm thick 20x20 cm2 tungsten plates were used to obtain different filter thicknesses and graphite bricks/blocks were used to form a reflector. Measurements of the dose enhancement of the simplified assembly in a water-filled head phantom were performed using a pair of tissue-equivalent ion chambers. One of the ion chambers is loaded with 1000-ppm natural boron (184-ppm 10B) to measure dose due to boron neutron capture. The

  14. Fast analysis of carbon content by inelastic scattering of neutrons

    International Nuclear Information System (INIS)

    Heinrich, B.; Irmer, K.; Poetschke, R.

    1986-01-01

    The direct measurement of carbon concentration of conveyor belts is a difficult problem. The great penetration depth by the fast neutrons and the 4.43 MeV γ-radiation gives an especially suitable method. The measurement were performed by the following methods: excitation of γ-radiation by a Pu-Be neutron source, excitation of γ-radiation by DT-neutron generator in stationary regime, in pulse regime, or coupled with time correlated associated particle method. Furthermore, a special Monte Carlo code in which the geometry of the measuring equipment could be specified, was written to calculate the 4.43 MeV γ counting rate for backscatter geometries and for penetration geometries. The influence of conveyor belt, of content of H, O, Fe and of mass by surface for 4.43 MeV γ-radiation was calculated for application brown coal in industry. (author)

  15. Verification of fast neutron spectrum calculation in coupled system HERBE

    International Nuclear Information System (INIS)

    Avdic, S.; Pesic, M.; Marinkovic, P.

    1995-01-01

    A high-resolution semiconductor spectrometer filled with 3 He gas, in diode coincidence arrangement, is applied to measure neutron spectrum in the centre of the fast core of the coupled fast-thermal system HERBE in the 'Vinca' Institute. The neutron spectrum is evaluated from measured pulse height distribution by using the HE3 computer code developed in the Nuclear Engineering Laboratory of the Institute of Nuclear Sciences VINCA. Experimental results are compared with the relevant multigroup calculations in the energy range from 2.5 MeV to 10.5 MeV. The measured spectrum provides a sufficient overlapping with the calculated one and no serious divergence is found in the measured energy range. (author)

  16. Fast neutron reactors: the safety point of view

    International Nuclear Information System (INIS)

    Laverie, M.; Avenas, M.

    1984-01-01

    All versions of nuclear reactors present favourable and unfavourable characteristics from the point of view of safety. The safety of the installations is obtained by making efforts to utilize in the best possible way those which are favourable and by taking proper steps in the face of those which are unfavourable. The present article shows how this general principle has been applied as regards the fast neutron reactors of integrated design which have been developped in France, taking into account the specific features of this version. A qualitative method to compare the safety of this version with that of pressurized water reactors which has been widely put to the test commercially all over the world is presented. These analyses make, generally speaking, several positive characteristics stand out for these fast neutron reactors from the safety aspects [fr

  17. Quantitative fuel motion determination with the CABRI fast neutron hodoscope

    International Nuclear Information System (INIS)

    Baumung, K.; Augier, G.

    1991-01-01

    The fast neutron hodoscope installed at the CABRI reactor in Cadarache, France, is employed to provide quantitative fuel motion data during experiments in which single liquid-metal fast breeder reactor test pins are subjected to simulated accident conditions. Instrument design and performance are reviewed, the methods for the quantitative evaluation are presented, and error sources are discussed. The most important findings are the axial expansion as a function of time, phenomena related to pin failure (such as time, location, pin failure mode, and fuel mass ejected after failure), and linear fuel mass distributions with a 2-cm axial resolution. In this paper the hodoscope results of the CABRI-1 program are summarized

  18. Fast Neutron Detection Using Pixelated CdZnTe Spectrometers

    Science.gov (United States)

    Streicher, Michael; Goodman, David; Zhu, Yuefeng; Brown, Steven; Kiff, Scott; He, Zhong

    2017-07-01

    Fast neutrons are an important signature of special nuclear materials (SNMs). They have a low natural background rate and readily penetrate high atomic number materials that easily shield gamma-ray signatures. Therefore, they provide a complementary signal to gamma rays for detecting shielded SNM. Scattering kinematics dictate that a large nucleus (such as Cd or Te) will recoil with small kinetic energy after an elastic collision with a fast neutron. Charge carrier recombination and quenching further reduce the recorded energy deposited. Thus, the energy threshold of CdZnTe detectors must be very low in order to sense the small signals from these recoils. In this paper, the threshold was reduced to less than 5 keVee to demonstrate that the 5.9-keV X-ray line from 55Fe could be separated from electronic noise. Elastic scattering neutron interactions were observed as small energy depositions (less than 20 keVee) using digitally sampled pulse waveforms from pixelated CdZnTe detectors. Characteristic gamma-ray lines from inelastic neutron scattering were also observed.

  19. A methodology of neutronic-thermodynamics simulation for fast reactor

    International Nuclear Information System (INIS)

    Waintraub, M.

    1986-01-01

    Aiming at a general optimization of the project, controlled fuel depletion and management, this paper develop a neutronic thermodynamics simulator, SIRZ, which besides being sufficiently precise, is also economic. That results in a 75% reduction in CPU time, for a startup calculation, when compared with the same calculation at the CITATION code. The simulation system by perturbation calculations, applied to fast reactors, which produce errors smaller than 1% in all components of the reference state given by the CITATION code was tested. (author)

  20. Effects of fast neutrons on chromatin: dependence on chromatin structure

    Energy Technology Data Exchange (ETDEWEB)

    Radu, L. [Dept. of Molecular Genetics, V. Babes National Inst., Bd. Timisoara, Bucharest (Romania); Constantinescu, B. [Dept. of Cyclotron, H. Hulubei National Inst., Bucharest (Romania); Gazdaru, D. [Dept. of Biophysics, Physics Faculty, Univ. of Bucharest (Romania)

    2002-07-01

    The effects of fast neutrons (10-100 Gy) on chromatin extracted from normal (liver of Wistar rats) and tumor (Walker carcinosarcoma maintained on Wistar rats) tissues were compared. The spectroscopic assays used were (i) chromatin intrinsic fluorescence, (ii) time-resolved fluorescence of chromatin-proflavine complexes, and (iii) fluorescence resonance energy transfer (FRET) between dansyl chloride and acridine orange coupled to chromatin. For both normal and tumor chromatin, the intensity of intrinsic fluorescence specific for acidic and basic proteins decreased with increasing dose. The relative contributions of the excited-state lifetime of proflavine bound to chromatin were reduced upon fast-neutron irradiation, indicating a decrease in the proportion of chromatin DNA available for ligand binding. The Forster energy transfer efficiencies were also modified by irradiation. These effects were larger for chromatin from tumor tissue. In the range 0-100 Gy, fast neutrons induced alterations in DNA and acidic and basic proteins, as well as in global chromatin structure. The radiosensitivity of chromatin extracted from tumor tissue seems to be higher than that of chromatin extracted from normal tissue, probably because of its higher euchromatin (loose)-heterochromatin (compact) ratio. (author)

  1. Genes involved in yeast survival after irradiation with fast neutrons

    International Nuclear Information System (INIS)

    Bozin, D.; Milosevic, M.J.

    2001-01-01

    Life on the Earth has evolved against a continuous background of ionizing radiation. It would be expected, therefore, that all possible mutations have been produced at some time or another; man-made radiation from medical or industrial sources will not result in any new types of mutation but will simply increase the whole spectrum of mutations that occur spontaneously. Any such lesion can be mutagenic and, in principle, lethal. To counteract the consequences of DNA damage, evolution has equipped all living cells with an intricate network of defense and repair systems. Together, these systems act as a kind of nuclear 'immune system' that is able to recognize and eliminate many types of DNA lesions. In the case of the yeast Saccharomyces cerevisiae, in these processes over 30 RAD genes participate. We tested the survival of haploid and diploid rad1 yeast mutant strains at a dose of 15 Gy of γ or fast neutron radiation. We demonstrated that the lethality of rad1 mutants both haploid and diploid are significantly higher after fast neutron irradiation. The results indicate to the role and position of these genes in the DNA repair of damages specifically induced by fast neutrons. (authors)

  2. A study on the optimum fast neutron flux for boron neutron capture therapy of deep-seated tumors.

    Science.gov (United States)

    Rasouli, Fatemeh S; Masoudi, S Farhad

    2015-02-01

    High-energy neutrons, named fast neutrons which have a number of undesirable biological effects on tissue, are a challenging problem in beam designing for Boron Neutron Capture Therapy, BNCT. In spite of this fact, there is not a widely accepted criterion to guide the beam designer to determine the appropriate contribution of fast neutrons in the spectrum. Although a number of researchers have proposed a target value for the ratio of fast neutron flux to epithermal neutron flux, it can be shown that this criterion may not provide the optimum treatment condition. This simulation study deals with the determination of the optimum contribution of fast neutron flux in the beam for BNCT of deep-seated tumors. Since the dose due to these high-energy neutrons damages shallow tissues, delivered dose to skin is considered as a measure for determining the acceptability of the designed beam. To serve this purpose, various beam shaping assemblies that result in different contribution of fast neutron flux are designed. The performances of the neutron beams corresponding to such configurations are assessed in a simulated head phantom. It is shown that the previously used criterion, which suggests a limit value for the contribution of fast neutrons in beam, does not necessarily provide the optimum condition. Accordingly, it is important to specify other complementary limits considering the energy of fast neutrons. By analyzing various neutron spectra, two limits on fast neutron flux are proposed and their validity is investigated. The results show that considering these limits together with the widely accepted IAEA criteria makes it possible to have a more realistic assessment of sufficiency of the designed beam. Satisfying these criteria not only leads to reduction of delivered dose to skin, but also increases the advantage depth in tissue and delivered dose to tumor during the treatment time. The Monte Carlo Code, MCNP-X, is used to perform these simulations. Copyright © 2014

  3. Spectroscopic fast neutron transmission imaging in a treaty verification setting

    Directory of Open Access Journals (Sweden)

    K. Ogren

    2018-01-01

    Full Text Available Measurements of the geometric configuration of objects and their material composition are needed for nuclear treaty verification purposes. We experimentally demonstrate a simple method based on monoenergetic fast neutron transmission to realize crude imaging of the geometric configuration of special nuclear material, confirm its fissionable content, and obtain information on its approximate fissile mass. In the experiment, we used monoenergetic neutrons from D(d, n3He and T(d, n4He reactions and a linear array of liquid scintillation detectors to perform spectroscopic neutron imaging of up to 13.7 kg of highly enriched uranium in a spherical geometry. We also show an example of detection of material diversion and confirm the presence of fissionable material based on the measurement of high-energy prompt fission neutrons, including estimating the quantity of material from the comparison of measured and predicted fission neutron emission rate. The combination of crude imaging and fissionable material detection and quantification in a simple approach may be attractive in certain treaty verification scenarios.

  4. Spectroscopic fast neutron transmission imaging in a treaty verification setting

    Science.gov (United States)

    Ogren, K.; Nattress, J.; Jovanovic, I.

    2018-01-01

    Measurements of the geometric configuration of objects and their material composition are needed for nuclear treaty verification purposes. We experimentally demonstrate a simple method based on monoenergetic fast neutron transmission to realize crude imaging of the geometric configuration of special nuclear material, confirm its fissionable content, and obtain information on its approximate fissile mass. In the experiment, we used monoenergetic neutrons from D(d, n)3He and T(d, n)4He reactions and a linear array of liquid scintillation detectors to perform spectroscopic neutron imaging of up to 13.7 kg of highly enriched uranium in a spherical geometry. We also show an example of detection of material diversion and confirm the presence of fissionable material based on the measurement of high-energy prompt fission neutrons, including estimating the quantity of material from the comparison of measured and predicted fission neutron emission rate. The combination of crude imaging and fissionable material detection and quantification in a simple approach may be attractive in certain treaty verification scenarios.

  5. Liquid scintillators and composites in fast neutron detection

    Science.gov (United States)

    Iwanowska, J.; Swiderski, L.; Moszynski, M.

    2012-04-01

    Helium-3 world crisis requires a development of new methods of neutron detection to replace commonly used 3He proportional counters. One of the option is application of liquid scintillators widely used in detection of fast neutrons, mostly in physics experiments, especially in applications where large volumes are required. Moreover, recently studied 10B loaded liquid scintillators cover detection of neutrons down to thermal energy. The several years' studies of liquid scintillators in our laboratory, brought us a knowledge about their efficiency to neutron detection, gamma sensitivity, etc. We have also tested composite scintillators, which are an alternative to organic single crystals, used in the 70's last century. In the report, we will present the results of the study of several liquid scintillators, also 10B loaded, as well as high flashpoint ones. We also show the neutron detection properties of some samples of composite scintillators. Composites are based on small grains of p-terphenyl or stilbene, introduced into a polymer matrix, which acts as a diffuser. The composite is encapsulated in a housing made of organic glass. P-terphenyl and stilbene are organic scintillators, which were commonly used in the seventies last century. They are characterized by good neutron/gamma discrimination properties. The present studies covers neutron/gamma discrimination by the zero-crossing method, a comparison of detection efficiency of liquid scintillators to 3He detectors and methods to reduce their gamma-ray sensitivity. In conclusion, a detection system, based on several small liquid cells of 2'' × 2'', is preferred, with pulse shape discrimination circuit equipped with the pile-up rejection circuit (PUR), as well as lead and tin shielding.

  6. Fast neutron dosimetry. Progress report, July 1, 1979-June 30, 1980

    Energy Technology Data Exchange (ETDEWEB)

    Attix, F.H.

    1980-01-01

    Progress is reported in: the development and testing of new gas mixtures more suitable for fast neutron dosimetry using the common A150-type Tissue-equivalent plastic ion chambers; comparison of photon doses determined with a graphite-walled proportional counter and with paired dosimeters irradiated by 14.8-MeV neutrons; a detector for the direct measurement of LET distributions from irradiation with fast neutrons; LET distributions from fast neutron irradiation of TE-plastic and graphite measured in a cylindrically symmetric geometry; progress in development of a tandem fast neutron and /sup 60/Co gamma ray source irradiation facility; an approach to the correlation of cellular response with lineal energy; calculated and measured HTO atmospheric dispersion rates within meters of a release site; application of cavity theory to fast neutrons; and fast neutron dosimetry by thermally stimulated currents in Al/sub 2/O/sub 3/. (GHT)

  7. Fast neutron dosimetry. Progress report, July 1, 1979-June 30, 1980

    International Nuclear Information System (INIS)

    Attix, F.H.

    1980-01-01

    Progress is reported in: the development and testing of new gas mixtures more suitable for fast neutron dosimetry using the common A150-type Tissue-equivalent plastic ion chambers; comparison of photon doses determined with a graphite-walled proportional counter and with paired dosimeters irradiated by 14.8-MeV neutrons; a detector for the direct measurement of LET distributions from irradiation with fast neutrons; LET distributions from fast neutron irradiation of TE-plastic and graphite measured in a cylindrically symmetric geometry; progress in development of a tandem fast neutron and 60 Co gamma ray source irradiation facility; an approach to the correlation of cellular response with lineal energy; calculated and measured HTO atmospheric dispersion rates within meters of a release site; application of cavity theory to fast neutrons; and fast neutron dosimetry by thermally stimulated currents in Al 2 O 3

  8. Study on neutron streaming effect in large fast critical assembly

    International Nuclear Information System (INIS)

    Takeda, Toshikazu; Yamaoka, Mitsuaki; Sakurai, Shungo; Tanimoto, Koichi; Abe, Yuhei

    1981-03-01

    A cell calculation method taking into account the neutron leakage from a cell and a transport calculation method treating the neutron streaming have been developed, and their applicability has been investigated. In the cell calculation method, the neutron leakage in the perpendicular direction to plates was treated by introducing an albedo collision probability which is a first-flight collision probability incorporating albedos at cell boundaries, and that in the parallel direction was treated by the pseudo absorption method. The use of the albedo collision probability made it possible to calculate the flux tilt in a cell exactly. This cell calculation method was applied to two slab models where fuel drawers were stacked in perpendicular and parallel directions to plates. Cell averaged cross sections calculated by the proposed method agreed well with those obtained from exact transport calculations treating the plate-wise heterogeneity, while the infinite cell calculation and the conventional pseudo absorption method produced about 2% errors in the cell-averaged cross sections. The cell-averaging procedure for control-rod channels was also proposed, and this method was applied to the calculation of control-rod worths and control-rod position worths. A transport calculation method based on the response matrix method has been proposed to treat the neutron streaming in fast critical assemblies directly. A response matrix code in two dimensional XY geometry RES2D was made. The accuracy of response matrices obtained from the RES2D code was checked by applying it to a slab cell and by comparing cell-averaged cross sections and k-infinity with those from a reference cell calculation based on the collision probability. The agreement of the results was good, and it was found that the response matrix method is very promising for the treatment of the neutron streaming in fast critical assemblies. (author)

  9. Fast-neutron activation analysis of manganese nodules

    International Nuclear Information System (INIS)

    Michaelis, W.; Fanger, H.U.; Mueller, A.; Pepelnik, R.

    1976-01-01

    The present paper describes the development of a new nuclear method that allows rapid determinations of the most relevant metals Ni and Cu without sample treatment, thus being particularly suited for quasi-continuous elemental analyses in mining and processing. The measurement is based on fast-neutron activation using Cockcroft-Walton generators, sealed neutron tubes or, possibly, (α,n)-type natural sources. Fast-neutron activation of manganese nodules is dominated by the (n,p)-reactions on Si, Al, Fe; the (n,α)-reaction on Mn and the (n,2n)-reaction on Cu. By choosing appropriate irradiation and cooling periods gamma-ray activities with comparatively simple spectral distributions are induced. From these spectra the Mn/Fe ratio in the nodules can be determined without the elaborate procedures usually required in absolute methods for eliminating systematic errors from fluctuations in sample and/or irradiation parameters. It is connected with the absolute Ni and Cu contents via well-known geochemical correlations which according to a lot of statistical data apply to quite different deposits and nodule types in the Pacific. Using these correlations the determination of the most important metals reduces to the evaluation of a peak area ratio. Measurements of the neutron flux distribution and the apparent sample density are unnecessary. The simple structure of the spectra allows the application of detectors with modest energy resolution, e.g. scintillation counters which can be manufactured as ruggedized crystal assemblies with great resistance to thermal and mechanical shock. The method is described in detail and possible interference, in particular from thermal and epithermal neutrons, are discussed. (orig.) [de

  10. A high gain energy amplifier operated with fast neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Rubbia, C. [CERN, Geneva (Switzerland)

    1995-10-01

    The basic concept and the main practical considerations of an Energy Amplifier (EA) have been exhaustively described elsewhere. Here the concept of the EA is further explored and additional schemes are described which offer a higher gain, a larger maximum power density and an extended burn-up. All these benefits stem from the use of fast neutrons, instead of thermal or epithermal ones, which was the case in the original study. The higher gain is due both to a more efficient high energy target configuration and to a larger, practical value of the multiplication factor. The higher power density results from the higher permissible neutron flux, which in turn is related to the reduced rate of {sup 233}Pa neutron captures (which, as is well known, suppress the formation of the fissile {sup 233}U fuel) and the much smaller k variations after switch-off due to {sup 233}Pa decays for a given burn-up rate. Finally a longer integrated burn-up is made possible by reduced capture rate by fission fragments of fast neutrons. In practice a 20 MW proton beam (20 mA @ 1 GeV) accelerated by a cyclotron will suffice to operate a compact EA at the level of {approx} 1 GW{sub e}. The integrated fuel burn-up can be extended in excess of 100 GW d/ton, limited by the mechanical survival of the fuel elements. Radio-Toxicity accumulated at the end of the cycle is found to be largely inferior to the one of an ordinary Reactor for the same energy produced. Schemes are proposed which make a {open_quotes}melt-down{close_quotes} virtually impossible. The conversion ratio, namely the rate of production of {sup 233}U relative to consumption is generally larger than unity, which permits production of fuel for other uses. Alternatively the neutron excess can be used to transform unwanted {open_quotes}ashes{close_quotes} into more acceptable elements.

  11. On the problem of monitoring the neutron parameters of the Fast Energy Amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Behringer, K.; Wydler, P

    1998-10-01

    The conceptual Fast Energy Amplifier, proposed by Rubbia et al. (1995), consists of a combination of a U-233/Th-232 fuelled fast-neutron subcritical facility with a proton accelerator. An intense beam of 1 GeV protons is injected into liquid lead at the core centre and drives the reactor by producing spallation neutrons. The burst of spallation neutrons produced by a single proton alters the basic neutron statistics which are well known for thermal neutrons in conventional nuclear reactors. A short assessment of standard neutron noise analysis methods is made with respect to monitoring neutron parameter data. (author) 18 refs., 14 figs., 3 tabs.

  12. Fast neutron dosimetry: [Progress report, 1986-1987

    International Nuclear Information System (INIS)

    DeLuca, P.M. Jr.; Gould, M.N.; Meisner, L.F.; Pearson, D.W.

    1987-01-01

    A new research area was initiated in ultrasoft x-rays with the University of Wisconsin 1-GeV electron storage ring used as a radiation source. A new beam line and irradiation apparatus was designed and constructed. Amongst the distinguishing features are an irradiation vessel of considerable generality allowing many types of radiological/biological experiments to be performed; the ability to maintain low-pressure, high humidity environments with good control; and a computer controlled sample slide for [X,Y,Z] motions of high precision that allows fully controlled velocities and accelerations for complex sample irradiations. Work in the area of chromosomal aberration studies has continued after the completion of the investigation into the possible synergistic effects of mixed beams of neutrons and photons. Of special interest is the damage dependence on absorbed dose and dose rate for low-dose and low-dose rate exposures to high LET radiation. A unique microdosimetric instrument was employed in the continuing effort to measure dose distribution in LET from fast neutron irradiation of metal-metal oxide walls. Our purpose is to determine this distribution for oxygen, an element of critical importance to fast neutron dosimetry. 31 refs., 7 figs., 2 tabs

  13. Measured and evaluated fast neutron cross sections of elemental nickel

    International Nuclear Information System (INIS)

    Guenther, P.; Smith, A.; Smith, D.; Whalen, J.; Howerton, R.

    1975-07-01

    Fast neutron total and scattering cross sections of elemental nickel are measured. Differential elastic scattering cross sections are determined from incident energies of 0.3 to 4.0 MeV. The cross sections for the inelastic neutron excitation of states at: 1.156 +- 0.015, 1.324 +- 0.015, 1.443 +- 0.015, 2.136 +- 0.013, 2.255 +- 0.030, 2.449 +- 0.030, 2.614 +- 0.020 and 2.791 +- 0.025 MeV are measured to incident neutron energies of 4.0 MeV. The total neutron cross sections are determined from 0.25 to 5.0 MeV. The experimental results are discussed in the context of optical and statistical models. It is shown that resonance width-fluctuation and correlation effects are significant. The present experimental and theoretical results, together with previously reported values, are used to construct a comprehensive evaluated elemental data file in the ENDF format. Some comparisons are made with previously reported evaluated files. In addition, some selected reactions which are widely used in dosimetry and other applications are presented as supplemental evaluated isotopic-data files. The numerical quantities are presented in tabular form. (3 tables, 29 figures)

  14. Ionizing Energy Depositions After Fast Neutron Interactions in Silicon

    CERN Document Server

    Bergmann, Benedikt; Caicedo, Ivan; Kierstead, James; Takai, Helio; Frojdh, Erik

    2016-01-01

    In this study we present the ionizing energy depositions in a 300 μm thick silicon layer after fast neutron impact. With the Time-of-Flight (ToF) technique, the ionizing energy deposition spectra of recoil silicons and secondary charged particles were assigned to (quasi-)monoenergetic neutron energies in the range from 180 keV to hundreds of MeV. We show and interpret representative measured energy spectra. By separating the ionizing energy losses of the recoil silicon from energy depositions by products of nuclear reactions, the competition of ionizing (IEL) and non-ionizing energy losses (NIEL) of a recoil silicon within the silicon lattice was investigated. The data give supplementary information to the results of a previous measurement and are compared with different theoretical predictions.

  15. Optimization of CR-39 for fast neutron dosimetry applications

    CERN Document Server

    Vilela, E; Giacomelli, G; Giorgini, M; Morelli, B; Patrizii, L; Serra, P; Togo, V

    1999-01-01

    We present the results of an experimental work aimed at improving the performances of the CR-39[reg] (Registered Trademark of PPG Industries Inc.) nuclear track detector for neutron dosimetry applications. The work was done in collaboration with the Intercast Europe S.p.A., producer of CR-39 for commercial and scientific applications. We compare the CR-39 made with different additives concentrations and different polymerization processes. We evaluate the response of the CR-39 to fast neutrons from three sources: sup 2 sup 4 sup 1 Am-Be, sup 2 sup 5 sup 2 Cf and sup 2 sup 3 sup 8 Pu-Li. Particular attention was paid to background fluctuations that limit the lower detectable dose.

  16. Random mask optimization for fast neutron coded aperture imaging

    Energy Technology Data Exchange (ETDEWEB)

    McMillan, Kyle [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Univ. of California, Los Angeles, CA (United States); Marleau, Peter [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Brubaker, Erik [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2015-05-01

    In coded aperture imaging, one of the most important factors determining the quality of reconstructed images is the choice of mask/aperture pattern. In many applications, uniformly redundant arrays (URAs) are widely accepted as the optimal mask pattern. Under ideal conditions, thin and highly opaque masks, URA patterns are mathematically constructed to provide artifact-free reconstruction however, the number of URAs for a chosen number of mask elements is limited and when highly penetrating particles such as fast neutrons and high-energy gamma-rays are being imaged, the optimum is seldom achieved. In this case more robust mask patterns that provide better reconstructed image quality may exist. Through the use of heuristic optimization methods and maximum likelihood expectation maximization (MLEM) image reconstruction, we show that for both point and extended neutron sources a random mask pattern can be optimized to provide better image quality than that of a URA.

  17. Overview of US fast-neutron facilities and testing capabilities

    International Nuclear Information System (INIS)

    Evans, E.A.; Cox, C.M.; Jackson, R.J.

    1982-01-01

    Rather than attempt a cataloging of the various fast neutron facilities developed and used in this country over the last 30 years, this paper will focus on those facilities which have been used to develop, proof test, and explore safety issues of fuels, materials and components for the breeder and fusion program. This survey paper will attempt to relate the evolution of facility capabilities with the evolution of development program which use the facilities. The work horse facilities for the breeder program are EBR-II, FFTF and TREAT. For the fusion program, RTNS-II and FMIT were selected

  18. Nuclear theory for fast neutron nuclear data evaluation

    International Nuclear Information System (INIS)

    1988-11-01

    The proceedings contain all invited and contributed papers presented at the Advisory Group Meeting on Nuclear Theory for Fast Neutron Data Evaluation held in Beijing 12-16 October 1987, as well as the conclusions and recommendations and the Chairman's summary of the meeting. The meeting presentations have been divided into six sessions devoted to the following topics: introductory speech (1 paper), optical potential (9 papers), compound nuclear theory (10 papers), pre-compound nuclear theory (13 papers), isomeric cross-section (1 paper) and intercomparison of nuclear model computer codes (1 paper). A separate abstract was prepared for each of these papers. Refs, figs and tabs

  19. Modern methods to improve the accuracy in fast neutron dosimetry

    International Nuclear Information System (INIS)

    Baers, B.; Karnani, H.; Seren, T.

    1985-01-01

    In order to improve the quality of fast neutron dose estimates at the reactor pressure vessel (PV) some modern methods are presented. In addition to basic principles, some error reduction procedures are also presented based on the combined use of relative measurements, direct sample taking from the pressure vessel and the use of iron and niobium as dosimeters. The influence of large systematic errors could be significantly reduced by carrying out relative measurements. This report also presents the successful use of niobium as a dosimeter by destructive treatment of PV samples. (author)

  20. Study on the fast neutron sensitivity of thermoluminescent detectors

    International Nuclear Information System (INIS)

    Szabo, P.P.; Palfalvi, J.

    1984-03-01

    Fast neutron (14.7 MeV) sensitivity of several thermoluminescent detectors was determined. The investigated detectors were MTS-N type pellets (made in Poland) used routinely in the authors' institute for personnel dosimetry, 7 LiF powder used for accident dosimetry, CaSO 4 :Dy and CaSO 4 :Tm powders (made in Hungary) used for enviromental monitoring and space dosimetry. Both free-in-air and on-phantom irradiations were performed. The new results are compared with responses calculated and measured earlier. (author)

  1. A novel detector assembly for detecting thermal neutrons, fast neutrons and gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Cester, D., E-mail: davide.cester@gmail.com [Dipartimento di Fisica ed Astronomia dell' Università di Padova, Via Marzolo 8, I-35131 Padova (Italy); Lunardon, M.; Moretto, S. [Dipartimento di Fisica ed Astronomia dell' Università di Padova, Via Marzolo 8, I-35131 Padova (Italy); INFN Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Nebbia, G. [INFN Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Pino, F. [Dipartimento di Fisica ed Astronomia dell' Università di Padova, Via Marzolo 8, I-35131 Padova (Italy); Sajo-Bohus, L. [Dipartimento di Fisica ed Astronomia dell' Università di Padova, Via Marzolo 8, I-35131 Padova (Italy); Laboratorio de Fisica Nuclear, Universidad Simon Bolivar, Apartado 89000, 1080 A Caracas (Venezuela, Bolivarian Republic of); Stevanato, L.; Bonesso, I.; Turato, F. [Dipartimento di Fisica ed Astronomia dell' Università di Padova, Via Marzolo 8, I-35131 Padova (Italy)

    2016-09-11

    A new composite detector has been developed by combining two different commercial scintillators. The device has the capability to detect gamma rays as well as thermal and fast neutrons; the signal discrimination between the three types is performed on-line by means of waveform digitizers and PSD algorithms. This work describes the assembled detector and its discrimination performance to be employed in the applied field.

  2. Microstructural evolution of martensitic steels during fast neutron iradiation

    International Nuclear Information System (INIS)

    Maziasz, P.J.

    1989-01-01

    Irradiation of martensitic/ferritic steels with fast neutrons (E > 0.1 MeV) to displacement damage levels of 30--50 dpa at temperatures of 300--500 degree C produces significant changes in the as-tempered microstructure. Dislocation loops and networks can be produced, irradiation-induced precipitates can form, the lath/subgrain boundary structure and the thermal precipitates produced during tempering can become unstable, and if helium is present, bubbles and voids can form. These microstructural changes caused by irradiation can have important effects on the properties of this class of steels for both fast breeder reactor (FBR) and magnetic fusion reactor (MFR) applications. The purpose of this paper is to compare reactor-irradiated and long-term thermally aged 9Cr--1MoVNb specimens, in order to distinguish effects due to displacement damage from those caused by elevated-temperature exposure alone. 7 refs., 1 fig

  3. Microstructural evolution in fast-neutron-irradiated austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Stoller, R.E.

    1987-12-01

    The present work has focused on the specific problem of fast-neutron-induced radiation damage to austenitic stainless steels. These steels are used as structural materials in current fast fission reactors and are proposed for use in future fusion reactors. Two primary components of the radiation damage are atomic displacements (in units of displacements per atom, or dpa) and the generation of helium by nuclear transmutation reactions. The radiation environment can be characterized by the ratio of helium to displacement production, the so-called He/dpa ratio. Radiation damage is evidenced microscopically by a complex microstructural evolution and macroscopically by density changes and altered mechanical properties. The purpose of this work was to provide additional understanding about mechanisms that determine microstructural evolution in current fast reactor environments and to identify the sensitivity of this evolution to changes in the He/dpa ratio. This latter sensitivity is of interest because the He/dpa ratio in a fusion reactor first wall will be about 30 times that in fast reactor fuel cladding. The approach followed in the present work was to use a combination of theoretical and experimental analysis. The experimental component of the work primarily involved the examination by transmission electron microscopy of specimens of a model austenitic alloy that had been irradiated in the Oak Ridge Research Reactor. A major aspect of the theoretical work was the development of a comprehensive model of microstructural evolution. This included explicit models for the evolution of the major extended defects observed in neutron irradiated steels: cavities, Frank faulted loops and the dislocation network. 340 refs., 95 figs., 18 tabs.

  4. Microstructural evolution in fast-neutron-irradiated austenitic stainless steels

    International Nuclear Information System (INIS)

    Stoller, R.E.

    1987-12-01

    The present work has focused on the specific problem of fast-neutron-induced radiation damage to austenitic stainless steels. These steels are used as structural materials in current fast fission reactors and are proposed for use in future fusion reactors. Two primary components of the radiation damage are atomic displacements (in units of displacements per atom, or dpa) and the generation of helium by nuclear transmutation reactions. The radiation environment can be characterized by the ratio of helium to displacement production, the so-called He/dpa ratio. Radiation damage is evidenced microscopically by a complex microstructural evolution and macroscopically by density changes and altered mechanical properties. The purpose of this work was to provide additional understanding about mechanisms that determine microstructural evolution in current fast reactor environments and to identify the sensitivity of this evolution to changes in the He/dpa ratio. This latter sensitivity is of interest because the He/dpa ratio in a fusion reactor first wall will be about 30 times that in fast reactor fuel cladding. The approach followed in the present work was to use a combination of theoretical and experimental analysis. The experimental component of the work primarily involved the examination by transmission electron microscopy of specimens of a model austenitic alloy that had been irradiated in the Oak Ridge Research Reactor. A major aspect of the theoretical work was the development of a comprehensive model of microstructural evolution. This included explicit models for the evolution of the major extended defects observed in neutron irradiated steels: cavities, Frank faulted loops and the dislocation network. 340 refs., 95 figs., 18 tabs

  5. Improvements in fast-neutron spectroscopy methods (1961)

    International Nuclear Information System (INIS)

    Cambou, F.

    1961-02-01

    This research aimed at improving fast-neutron electronic detectors based on n-p elastic scattering. The first part concerns proportional counters; careful constructional methods have made it possible to plot mono-energetic neutron spectra in the range 700 keV - 3 MeV with a resolution of 7 per cent. The second part concerns scintillation counters: an organic scintillator and an inorganic scintillator covered with a thin layer of a scattering agent. An exact study of the types of scintillation has made it possible to develop efficient discriminator circuits. Different neutron spectra plotted in the presence of a strong gamma background are presented. The last part deals with the development of form discrimination methods for the study, in the actual beam, of the elastic scattering of 14.58 MeV electrons. With hydrogen, the distribution f (φ) of the recoil protons is f(φ) = 1 + 0.034 cos φ + 0.042 cos 2 φ. With tritium the scattering is strongly anisotropic; the curve representing the variation of the differential cross-section for the elastic scattering in the centre of mass system is obtained with a target containing 1 cm 3 of tritium. (author) [fr

  6. Neutron diffraction analysis of Cr–Ni–Mo–Ti austenitic steel after cold plastic deformation and fast neutrons irradiation

    International Nuclear Information System (INIS)

    Voronin, V.I.; Valiev, E.Z.; Berger, I.F.; Goschitskii, B.N.; Proskurnina, N.V.; Sagaradze, V.V.; Kataeva, N.F.

    2015-01-01

    A quantitative assessment is presented of the dislocation density and relative fractions of edge and screw dislocations in reactor-steel samples 16Cr–15Ni–3Mo–1Ti subjected to preliminary cold deformation by rolling and subsequent fast neutron irradiation using neutron diffraction analysis. The Williamson–Hall modified method was used for calculations. It is shown that the fast neutron irradiation leads to a decrease in the density of dislocations that appeared after samples deformation. The applicability of neutron diffraction analysis to the examination of dislocation structure of deformed and irradiated materials is shown

  7. Neutron diffraction analysis of Cr-Ni-Mo-Ti austenitic steel after cold plastic deformation and fast neutrons irradiation

    Science.gov (United States)

    Voronin, V. I.; Valiev, E. Z.; Berger, I. F.; Goschitskii, B. N.; Proskurnina, N. V.; Sagaradze, V. V.; Kataeva, N. F.

    2015-04-01

    A quantitative assessment is presented of the dislocation density and relative fractions of edge and screw dislocations in reactor-steel samples 16Cr-15Ni-3Mo-1Ti subjected to preliminary cold deformation by rolling and subsequent fast neutron irradiation using neutron diffraction analysis. The Williamson-Hall modified method was used for calculations. It is shown that the fast neutron irradiation leads to a decrease in the density of dislocations that appeared after samples deformation. The applicability of neutron diffraction analysis to the examination of dislocation structure of deformed and irradiated materials is shown.

  8. Some Applications of Fast Neutron Activation Analysis of Oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Owrang, Farshid

    2003-07-01

    In this thesis we focus on applications of neutron activation of oxygen for several purposes: A) measuring the water level in a laboratory tank, B) measuring the water flow in a pipe system set-up, C) analysing the oxygen in combustion products formed in a modern gasoline SI engine, and D) measuring on-line the amount of oxygen in bulk liquids. A) Water level measurements. The purpose of this work was to perform radiation based water level measurements, aimed at nuclear reactor vessels, on a laboratory scale. A laboratory water tank was irradiated by fast neutrons from a neutron generator. The water was activated at different water levels and the water level was decreased. The produced gamma radiation was measured using two detectors at different heights. The results showed that the method is suitable for measurement of water level and that a relatively small experimental set-up can be used for developing methods for water level measurements in real boiling water reactors based on activated oxygen in the water. B) Water flows in pipe. The goal in this work was to investigate the asymmetric distribution of activity in flow measurements with pulsed neutron activation (PNA) in a laboratory piping system. Earlier investigations had shown a discrepancy between the measured velocity of the activated water by PNA and the true mean velocity in the pipe. This discrepancy decreased with larger distances from the activation point. It was speculated that the induced activity in the pipe did not distribute homogeneously. With inhomogeneous radial distribution of activity in combination with a velocity profile in the pipe, the activated water may not have the same velocity as the mean velocity of water in the pipe. To study this phenomenon, a water-soluble colour was injected into a transparent pipe for simulation of the transport of the activated water. The radial concentration of the colour, at different distances from the activation point, was determined. The result

  9. Some Applications of Fast Neutron Activation Analysis of Oxygen

    International Nuclear Information System (INIS)

    Owrang, Farshid

    2003-01-01

    In this thesis we focus on applications of neutron activation of oxygen for several purposes: A) measuring the water level in a laboratory tank, B) measuring the water flow in a pipe system set-up, C) analysing the oxygen in combustion products formed in a modern gasoline SI engine, and D) measuring on-line the amount of oxygen in bulk liquids. A) Water level measurements. The purpose of this work was to perform radiation based water level measurements, aimed at nuclear reactor vessels, on a laboratory scale. A laboratory water tank was irradiated by fast neutrons from a neutron generator. The water was activated at different water levels and the water level was decreased. The produced gamma radiation was measured using two detectors at different heights. The results showed that the method is suitable for measurement of water level and that a relatively small experimental set-up can be used for developing methods for water level measurements in real boiling water reactors based on activated oxygen in the water. B) Water flows in pipe. The goal in this work was to investigate the asymmetric distribution of activity in flow measurements with pulsed neutron activation (PNA) in a laboratory piping system. Earlier investigations had shown a discrepancy between the measured velocity of the activated water by PNA and the true mean velocity in the pipe. This discrepancy decreased with larger distances from the activation point. It was speculated that the induced activity in the pipe did not distribute homogeneously. With inhomogeneous radial distribution of activity in combination with a velocity profile in the pipe, the activated water may not have the same velocity as the mean velocity of water in the pipe. To study this phenomenon, a water-soluble colour was injected into a transparent pipe for simulation of the transport of the activated water. The radial concentration of the colour, at different distances from the activation point, was determined. The result

  10. Dose Calibration of the ISS-RAD Fast Neutron Detector

    Science.gov (United States)

    Zeitlin, C.

    2015-01-01

    The ISS-RAD instrument has been fabricated by Southwest Research Institute and delivered to NASA for flight to the ISS in late 2015 or early 2016. ISS-RAD is essentially two instruments that share a common interface to ISS. The two instruments are the Charged Particle Detector (CPD), which is very similar to the MSL-RAD detector on Mars, and the Fast Neutron Detector (FND), which is a boron-loaded plastic scintillator with readout optimized for the 0.5 to 10 MeV energy range. As the FND is completely new, it has been necessary to develop methodology to allow it to be used to measure the neutron dose and dose equivalent. This talk will focus on the methods developed and their implementation using calibration data obtained in quasi-monoenergetic (QMN) neutron fields at the PTB facility in Braunschweig, Germany. The QMN data allow us to determine an approximate response function, from which we estimate dose and dose equivalent contributions per detected neutron as a function of the pulse height. We refer to these as the "pSv per count" curves for dose equivalent and the "pGy per count" curves for dose. The FND is required to provide a dose equivalent measurement with an accuracy of ?10% of the known value in a calibrated AmBe field. Four variants of the analysis method were developed, corresponding to two different approximations of the pSv per count curve, and two different implementations, one for real-time analysis onboard ISS and one for ground analysis. We will show that the preferred method, when applied in either real-time or ground analysis, yields good accuracy for the AmBe field. We find that the real-time algorithm is more susceptible to chance-coincidence background than is the algorithm used in ground analysis, so that the best estimates will come from the latter.

  11. Bubble masks for time-encoded imaging of fast neutrons.

    Energy Technology Data Exchange (ETDEWEB)

    Brubaker, Erik; Brennan, James S.; Marleau, Peter; Nowack, Aaron B.; Steele, John T.; Sweany, Melinda; Throckmorton, Daniel J.

    2013-09-01

    Time-encoded imaging is an approach to directional radiation detection that is being developed at SNL with a focus on fast neutron directional detection. In this technique, a time modulation of a detected neutron signal is inducedtypically, a moving mask that attenuates neutrons with a time structure that depends on the source position. An important challenge in time-encoded imaging is to develop high-resolution two-dimensional imaging capabilities; building a mechanically moving high-resolution mask presents challenges both theoretical and technical. We have investigated an alternative to mechanical masks that replaces the solid mask with a liquid such as mineral oil. Instead of fixed blocks of solid material that move in pre-defined patterns, the oil is contained in tubing structures, and carefully introduced air gapsbubblespropagate through the tubing, generating moving patterns of oil mask elements and air apertures. Compared to current moving-mask techniques, the bubble mask is simple, since mechanical motion is replaced by gravity-driven bubble propagation; it is flexible, since arbitrary bubble patterns can be generated by a software-controlled valve actuator; and it is potentially high performance, since the tubing and bubble size can be tuned for high-resolution imaging requirements. We have built and tested various single-tube mask elements, and will present results on bubble introduction and propagation as a function of tubing size and cross-sectional shape; real-time bubble position tracking; neutron source imaging tests; and reconstruction techniques demonstrated on simple test data as well as a simulated full detector system.

  12. Preliminary On-Orbit Neutron Dose Equivalent and Energy Spectrum Results from the ISS-RAD Fast Neutron Detector (FND)

    Science.gov (United States)

    Semones, Edward; Leitgab, Martin

    2016-01-01

    The ISS-RAD instrument was activated on ISS on February 1st, 2016. Integrated in ISS-RAD, the Fast Neutron Detector (FND) performs, for the first time on ISS, routine and precise direct neutron measurements between 0.5 and 8 MeV. Preliminary results for neutron dose equivalent and neutron flux energy distributions from online/on-board algorithms and offline ground analyses will be shown, along with comparisons to simulated data and previously measured neutron spectral data. On-orbit data quality and pre-launch analysis validation results will be discussed as well.

  13. Fast neutron measurements with 7Li and 6Li enriched CLYC scintillators

    International Nuclear Information System (INIS)

    Giaz, A.; Blasi, N.; Boiano, C.; Brambilla, S.; Camera, F.; Cattadori, C.; Ceruti, S.; Gramegna, F.; Marchi, T.; Mattei, I.; Mentana, A.; Million, B.; Pellegri, L.; Rebai, M.; Riboldi, S.; Salamida, F.; Tardocchi, M.

    2016-01-01

    The recently developed Cs 2 LiYCl 6 :Ce (CLYC) crystals are interesting scintillation detectors not only for their gamma energy resolution (<5% at 662 keV) but also for their capability to identify and measure the energy of both gamma rays and fast/thermal neutrons. The thermal neutrons were detected by the 6 Li(n,α)t reaction while for the fast neutrons the 35 Cl(n,p) 35 S and 35 Cl(n,α) 32 P neutron-capture reactions were exploited. The energy of the outgoing proton or α particle scales linearly with the incident neutron energy. The kinetic energy of the fast neutrons can be measured using both the Time Of Flight (TOF) technique and using the CLYC energy signal. In this work, the response to monochromatic fast neutrons (1.9–3.8 MeV) of two CLYC 1″×1″ crystals was measured using both the TOF and the energy signal. The observables were combined to identify fast neutrons, to subtract the thermal neutron background and to identify different fast neutron-capture reactions on 35 Cl, in other words to understand if the detected particle is an α or a proton. We performed a dedicated measurement at the CN accelerator facility of the INFN Legnaro National Laboratories (Italy), where the fast neutrons were produced by impinging a proton beam (4.5, 5.0 and 5.5 MeV) on a 7 LiF target. We tested a CLYC detector 6 Li-enriched at about 95%, which is ideal for thermal neutron measurements, in parallel with another CLYC detector 7 Li-enriched at more than 99%, which is suitable for fast neutron measurements.

  14. Neutron Age Determination in Fast Reactor Materials using the Group Method

    Directory of Open Access Journals (Sweden)

    Kabanova Marina F.

    2016-01-01

    Full Text Available The article deals with the methods of identifying fast neutron age in sodium (Na and uranium-238 (238U; describes the model of advanced and effective fast neutron nuclear reactors (FN, where Na is a coolant while 238U is involved in the fuel cycle in large quantities; justifies the choice of the group method for calculating the neutron age value in the substances mentioned above that can show the accuracy of the used constants for Na and estimate various versions of multilevel description of neutron moderation in 238U – the most powerful resonance absorber of the neutron reactor active zone.

  15. How resilient is the soybean genome? Insights from fast neutron mutagenesis

    Science.gov (United States)

    Previously, we described the development of a fast neutron mutant population resource in soybean and identified mutations of interest through phenotypic screening. Here, we consider the resiliency of the soybean genome by examining genomic rearrangements and mutations that arise from fast neutron ra...

  16. Integral test of JENDL dosimetry file using fast neutron field in the Experimental Fast Reactor JOYO

    International Nuclear Information System (INIS)

    Aoyama, Takafumi; Sekine, Takashi

    1999-09-01

    In order to evaluate the applicability of the JENDL dosimetry file, an integral test using a fast neutron spectrum field in the Experimental Fast Reactor JOYO Mark-II core was performed. The dosimeter set consisting of eight reactions of 46 Ti(n,p) 46 Sc, 54 Fe(n,p) 54 Mn, 58 Fe(n,γ) 59 Fe, 58 Ni(n,p) 58 Co, 59 Co(n,γ) 60 Co, 63 Cu(n,α) 60 Co, 238 U fission and 237 Np fission was irradiated for approximately 30 days near the core center of the JOYO Mk-II. Neutron flux at the dosimeter position was calculated using the two dimensional discrete ordinate transport code 'DORT'. The core configuration was modeled in XY geometry, and the 100 group cross section set of JSD-J2 / JFT-J2, which was processed from JENDL-2, was utilized. The absolute value of neutron flux was normalized so that the 235 U fission rate using the calculated neutron spectrum agreed with the measured reaction rate. The 103 group cross section data were processed by 'NJOY' code for nuclides to be used in the JOYO dosimetry. As the results of integral test for JENDL/D-99 (new file) and JENDL/D-91 (previous file), calculated values by JENDL/D-99 agreed well with the experimental values, and the C/E ratios ranged from 0.95 to 1.22. By comparing the results between JENDL/D-99 and JENDL/D-91, small differences exist, except for 58 Fe(n, γ) 59 Fe reaction, which was improved significantly in JENDL/D-99. (author)

  17. Fast Neutron Damage Studies on NdFeB Materials

    CERN Document Server

    Spencer, James; Baldwin, A; Boussoufi, Moe; Pellet, David; Volk, James T; Wolf, Zachary

    2005-01-01

    Many materials and electronics need to be tested for the radiation environment expected at linear colliders (LC) where the accelerator and detectors will be subjected to large fluences of hadrons, leptons and gammas over the life of the facility. Although the linacs will be superconducting, there are still many potential uses for NdFeB in the damping rings, injection and extraction lines and final focus. Our understanding of the radiation damage situation for rare earth permanent magnet materials was presented at PAC2003 and our first measurements of fast neutron, stepped doses at the UC Davis McClellan Nuclear Reactor Center (UCD MNRC) were presented at EPAC2004 where the damage appeared proportional to the distances between the effective operating points and Hc. Here we have extended those doses and included more commercial samples together with the induced radioactivities associated with their respective dopants. Hall probe data for the external induction distributions are compared with vector magnetizatio...

  18. Fast Neutron Damage Studies on NdFeB Materials

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, S.; Spencer, J.; Wolf, Z.; /SLAC; Baldwin, A.; Pellett, D.; Boussoufi, M.; /UC, Davis

    2005-05-17

    Many materials and electronics need to be tested for the radiation environment expected at linear colliders (LC) since both accelerator and detectors will be subjected to large fluences of hadrons, leptons and {gamma}'s over the life of the facility [1]. While the linacs will be superconducting, there are still many uses for NdFeB in the damping rings, injection and extraction lines and final focus. Our understanding of the situation for rare earth, permanent magnet materials was presented at PAC03 [2]. Our first measurements of fast neutron, stepped doses at the UC Davis McClellan Nuclear Reactor Center (UCD MNRC) were presented at EPAC04 [3]. We have extended the doses, included other manufacturer's samples, and measured induced radioactivities which are discussed in detail.

  19. Fast neutron detection using solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Vilela, E.C.

    1990-01-01

    CR-39 and Makrofol-E solid state nuclear track detectors were studied aiming their application to fast neutron detection. Optimum etching conditions of those two kinds of materials were determined the followings - the Makrofol-E detector is electrochemically etched in a PEW solution (15% KOH, 40% ethilic alcohol and 45% water) for 2 h., with an applied electric field strength of 30 kV/cm (r/m/s/) and frequency of 2 kHz, at room temperature; - the CR-39 detector is chemically pre-etched during 1 h in a 20% (w/v) NaOH solution at 70 sup(0)C, followed by 13 h electrochemical etch using the same solution at room temperature and an electric field strength of 30 kV/cm (r.m.s.) and frequency of 2 kHz.(E.G.)

  20. Indium antimonide crystal defects formed by fast neutron irradiation

    International Nuclear Information System (INIS)

    Vitovskij, N.A.; Dolgolenko, A.P.; Mashovets, T.V.; Oganesyan, O.V.

    1979-01-01

    It is shown, that indium antimonide irradiation with fast neutrons of reactor results in the formation of disorded regions with a mean radius of approximately 130 A surrounded with space charge regions forming barriers for main carriers. But the found values of defect cluster depolarization coefficient (Lsub(x)sup(n)=0.18 and Lsub(x)sup(p)=0.29) show, that the clusters have marked conductivity for main charge carriers. The found position of the Fermi level in the disorded regions Esub(F)=Esub(c)-0.085 eV does not depend on the impurity type and its concentration in an initial material. The disorded regions play the main part in charge carrier scattering at low temperatures and markedly contribute to the change of mobility at 80 K. It is found, that irradiation temperature change in the range from 77 to 300 K does not effect practically on the disorded region parameters

  1. RBE values of fast neutrons for damage to organized tissues in experimental animals

    International Nuclear Information System (INIS)

    Broerse, J.J.

    1975-01-01

    The relative biological effectiveness of fast neutrons for damage to organized tissues in experimental animals is discussed. Information about basic mechanisms through which damage in mammalian tissues is induced and expressed is also discussed. The following topics are included in the discussion: energy deposition characteristics of fast-neutron beams; quantitative determination of normal tissue damage; and RBE values as a function of neutron energy

  2. Measurement system of gamma, X, thermal and/or fast neutron flux

    International Nuclear Information System (INIS)

    Siffert, P.; Regal, R.; Koebel, J.M.; Teissier, C.

    1987-01-01

    The system includes detection means of gamma or/and X radiation, detection means of gamma and/or X radiation from thermal neutrons, detection means of gamma and/or X radiation from thermal and/or fast neutrons. It includes also processing devices of the signals given by the detection means able to get a linear combination of the detected signals. These processing devices give a signal selectively representative of photon, thermal or fast neutron rate [fr

  3. A Time of Flight Fast Neutron Imaging System Design Study

    Science.gov (United States)

    Canion, Bonnie; Glenn, Andrew; Sheets, Steven; Wurtz, Ron; Nakae, Les; Hausladen, Paul; McConchie, Seth; Blackston, Matthew; Fabris, Lorenzo; Newby, Jason

    2017-09-01

    LLNL and ORNL are designing an active/passive fast neutron imaging system that is flexible to non-ideal detector positioning. It is often not possible to move an inspection object in fieldable imager applications such as safeguards, arms control treaty verification, and emergency response. Particularly, we are interested in scenarios which inspectors do not have access to all sides of an inspection object, due to interfering objects or walls. This paper will present the results of a simulation-based design parameter study, that will determine the optimum system design parameters for a fieldable system to perform time-of-flight based imaging analysis. The imaging analysis is based on the use of an associated particle imaging deuterium-tritium (API DT) neutron generator to get the time-of-flight of radiation induced within an inspection object. This design study will investigate the optimum design parameters for such a system (e.g. detector size, ideal placement, etc.), as well as the upper and lower feasible design parameters that the system can expect to provide results within a reasonable amount of time (e.g. minimum/maximum detector efficiency, detector standoff, etc.). Ideally the final prototype from this project will be capable of using full-access techniques, such as transmission imaging, when the measurement circumstances allow, but with the additional capability of producing results at reduced accessibility.

  4. Tests for validation of fast neutron reactors safety

    International Nuclear Information System (INIS)

    Nagata, T.; Yamashita, H.

    2001-01-01

    Japanese scientific research and design enterprises in cooperation with industrial and power generating corporations implement a project on creating a fast neutron reactor of the ultimate safety. One of the basic expected results from such a development is creation of a reactor core structure that is able to eliminate recriticality occurrence in the course of reactor accident involving fuel melting. One of the possible ways to solve this problem is to include pipes (meant for specifying directed (controlled) molten fuel relocation) into fuel assembly structure. In the course of conduction and subsequent implementation of such a design the basic issue is to experimentally confirm the operating capacity of FA having such a structure and that is called FAIDUS. Within EAGLE Project on experimental basis of IAE NNC RK an activity has been started on preparation and conduction of out-of-pile and in-pile tests. During tests a sodium coolant will be used. Studies are conducted by NNC RK in cooperation with the Japanese corporations JAPC and JNC. Basic objective of out-of-pile tests was to obtain preliminary information on fuel relocation behavior under conditions simulating accident involving melting of core consisting of FAIDUS FA, which will help to clarify simulation criteria and to develop the most optimum structure of the experimental channel for reactor experiments conduction. The basic objective of in-pile tests was the experimental confirmation of operating capacity of FAIDUS FA model under reactor conditions. According to the program two tests are planned to be performed at IGR reactor: tests for validation of fast neutron reactor safety, and out-of-pile tests at EAGLE experimental facility without sodium coolant

  5. Benchmark test of evaluated nuclear data files for fast reactor neutronics application

    International Nuclear Information System (INIS)

    Chiba, Go; Hazama, Taira; Iwai, Takehiko; Numata, Kazuyuki

    2007-07-01

    A benchmark test of the latest evaluated nuclear data files, JENDL-3.3, JEFF-3.1 and ENDF/B-VII.0, has been carried out for fast reactor neutronics application. For this benchmark test, experimental data obtained at fast critical assemblies and fast power reactors are utilized. In addition to comparing of numerical solutions with the experimental data, we have extracted several cross sections, in which differences between three nuclear data files affect significantly numerical solutions, by virtue of sensitivity analyses. This benchmark test concludes that ENDF/B-VII.0 predicts well the neutronics characteristics of fast neutron systems rather than the other nuclear data files. (author)

  6. Validation of computational methods for treatment planning of fast-neutron therapy using activation foil techniques

    International Nuclear Information System (INIS)

    Nigg, D.W.; Wemple, C.A.; Hartwell, J.K.; Harker, Y.D.; Venhuizen, J.R.; Risler, R.

    1997-12-01

    A closed-form direct method for unfolding neutron spectra from foil activation data is presented. The method is applied to measurements of the free-field neutron spectrum produced by the proton-cyclotron-based fast-neutron radiotherapy facility at the University of Washington (UW) School of Medicine. The results compare favorably with theoretical expectations based on an a-priori calculational model of the target and neutron beamline configuration of the UW facility

  7. The relationship between contrast, resolution and detectability in accelerator-based fast neutron radiography

    International Nuclear Information System (INIS)

    Ambrosi, R. M.; Watterson, J. I. W.

    1999-01-01

    Fast neutron radiography as a method for non destructive testing is a fast growing field of research. At the Schonland Research Center for Nuclear Sciences we have been engaged in the formulation of a model for the physics of image formation in fast neutron radiography (FNR). This involves examining all the various factors that affect image formation in FNR by experimental and Monte Carlo methods. One of the major problems in the development of a model for fast neutron radiography is the determination of the factors that affect image contrast and resolution. Monte Carlo methods offer an ideal tool for the determination of the origin of many of these factors. In previous work the focus of these methods has been the determination of the scattered neutron field in both a scintillator and a fast neutron radiography facility. As an extension of this work MCNP has been used to evaluate the role neutron scattering in a specimen plays in image detectability. Image processing of fast neutron radiographs is a necessary method of enhancing the detectability of features in an image. MCNP has been used to determine the part it can play in indirectly improving image resolution and aiding in image processing. The role noise plays in fast neutron radiography and its impact on image reconstruction has been evaluated. All these factors aid in the development of a model describing the relationship between contrast, resolution and detectability

  8. High-sensitive spectrometer of fast neutrons and the results of fast neutron background flux measurements at the Gallium-Germanium Solar Neutrino Experiment

    CERN Document Server

    Abdurashitov, J N; Kalikhov, A V; Matushko, V L; Shikhin, A A; Yants, V E; Zaborskaia, O S

    2002-01-01

    The principle of operation, design, registration system and main characteristics of a fast neutron spectrometer are described. The spectrometer is intended for direct measurements of ultra low fluxes of fast neutrons. It is sensitive to neutron fluxes of 10 sup - sup 7 cm sup - sup 2 s sup - sup 1 and lower. The detection efficiency of fast neutrons with simultaneous energy measurement was determined from Monte-Carlo simulation to be equal to 0.11+-0.01. The background counting rate in the detector corresponds to a neutron flux of (6.5+-2.1)x10 sup - sup 7 cm sup - sup 2 s sup - sup 1 in the range 1.0-11.0 MeV. The natural neutron flux from the surrounding mine rock at the depth of 4600 m of water equivalent was measured to be (7.3+-2.4)x10 sup - sup 7 cm sup - sup 2 s sup - sup 1 in the range 1.0-11.0 MeV. The flux of fast neutrons in the SAGE main room was measured to be <2.3x10 sup - sup 7 cm sup - sup 2 s sup - sup 1 in 1.0-11.0 MeV energy range.

  9. The CLYC-6 and CLYC-7 response to γ-rays, fast and thermal neutrons

    International Nuclear Information System (INIS)

    Giaz, A.; Pellegri, L.; Camera, F.; Blasi, N.; Brambilla, S.; Ceruti, S.; Million, B.; Riboldi, S.; Cazzaniga, C.; Gorini, G.; Nocente, M.; Pietropaolo, A.; Pillon, M.; Rebai, M.; Tardocchi, M.

    2016-01-01

    The crystal Cs 2 LiYCl 6 :Ce (CLYC) is a very interesting scintillator material because of its good energy resolution and its capability to identify γ-rays and fast/thermal neutrons. The crystal Cs 2 LiYCl 6 :Ce contains 6 Li and 35 Cl isotopes, therefore, it is possible to detect thermal neutrons through the reaction 6 Li(n, α)t while 35 Cl ions allow to measure fast neutrons through the reactions 35 Cl(n, p) 35 S and 35 Cl(n, α) 32 P. In this work two CLYC 1″×1″ crystals were used: the first crystal, enriched with 6 Li at 95% (CLYC-6) is ideal for thermal neutron measurements while the second one, enriched with 7 Li at >99% (CLYC-7) is suitable for fast neutron measurements. The response of CLYC scintillators was measured with different PMT models: timing or spectroscopic, with borosilicate glass or quartz window. The energy resolution, the neutron-γ discrimination and the internal activity are discussed. The capability of CLYC scintillators to discriminate γ rays from neutrons was tested with both thermal and fast neutrons. The thermal neutrons were measured with both detectors, using an AmBe source. The measurements of fast neutrons were performed at the Frascati Neutron Generator facility (Italy) where a deuterium beam was accelerated on a deuterium or on a tritium target, providing neutrons of 2.5 MeV or 14.1 MeV, respectively. The different sensitivity to thermal and fast neutrons of a CLYC-6 and of a CLYC-7 was additionally studied.

  10. 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

  11. Status review of methods for the calculation of fast neutron nuclear data for structural materials of fast and fusion reactors

    International Nuclear Information System (INIS)

    Goulo, V.

    1989-01-01

    The report contains the texts of the 9 invited papers delivered during the Second Research Co-ordination Meeting on ''Methods for the Calculation of Fast Neutron Nuclear Data for Structural Materials and Fast and Fusion Reactors'' held in Vienna during 15-17 February 1988. A separate abstract was prepared for each of these 9 papers. Refs, figs and tabs

  12. Feasibility study of Self Powered Neutron Detectors in Fast Reactors for detecting local change in neutron flux distribution

    International Nuclear Information System (INIS)

    Jammes, Christian; Filliatre, Philippe; Verma, Vasudha; Hellesen, Carl; Jacobsson Svard, Staffan

    2015-01-01

    Neutron flux monitoring system forms an integral part of the design of a Generation IV sodium cooled fast reactor system. Diverse possibilities of detector systems installation have to be investigated with respect to practicality and feasibility according to the detection parameters. In this paper, we demonstrate the feasibility of using self powered neutron detectors as in-core detectors in fast reactors for detecting local change in neutron flux distribution. We show that the gamma contribution from fission products decay in the fuel and activation of structural materials is very small compared to the fission gammas. Thus, it is possible for the in-core SPND signal to follow changes in local neutron flux as they are proportional to each other. This implies that the signal from an in-core SPND can provide dynamic information on the neutron flux perturbations occurring inside the reactor core. (authors)

  13. Fast-neutron detecting system with n, γ discrimination

    International Nuclear Information System (INIS)

    Ouyang Xiaoping; Huang Bao; Cao Jinyun

    1997-11-01

    In the present work, a new type neutron detecting system is reported, which can absolutely measure neutron parameters in n + γ mixed fields and has a long continuance of static high vacuum of 10 -4 Pa. The detecting system, with middle neutron-detecting sensitivity, short time response and big linear current output, has applied successfully in pulsed neutron beam measurement

  14. Fast ultrasonic visualisation under sodium. Application to the fast neutron reactors; Visualisation ultrasonore rapide sous sodium. application aux reacteurs a neutrons rapides

    Energy Technology Data Exchange (ETDEWEB)

    Imbert, Ch

    1997-05-30

    The fast ultrasonic visualization under sodium is in the programme of research and development on the inspection inside the fast neutron reactors. This work is about the development of a such system of fast ultrasonic imaging under sodium, in order to improve the existing visualization systems. This system is based on the principle of orthogonal imaging, it uses two linear antennas with an important dephasing having 128 piezo-composite elements of central frequency equal to 1.6 MHz. (N.C.)

  15. A hybrid source-driven method to compute fast neutron fluence in reactor pressure vessel - 017

    International Nuclear Information System (INIS)

    Ren-Tai, Chiang

    2010-01-01

    A hybrid source-driven method is developed to compute fast neutron fluence with neutron energy greater than 1 MeV in nuclear reactor pressure vessel (RPV). The method determines neutron flux by solving a steady-state neutron transport equation with hybrid neutron sources composed of peripheral fixed fission neutron sources and interior chain-reacted fission neutron sources. The relative rod-by-rod power distribution of the peripheral assemblies in a nuclear reactor obtained from reactor core depletion calculations and subsequent rod-by-rod power reconstruction is employed as the relative rod-by-rod fixed fission neutron source distribution. All fissionable nuclides other than U-238 (such as U-234, U-235, U-236, Pu-239 etc) are replaced with U-238 to avoid counting the fission contribution twice and to preserve fast neutron attenuation for heavy nuclides in the peripheral assemblies. An example is provided to show the feasibility of the method. Since the interior fuels only have a marginal impact on RPV fluence results due to rapid attenuation of interior fast fission neutrons, a generic set or one of several generic sets of interior fuels can be used as the driver and only the neutron sources in the peripheral assemblies will be changed in subsequent hybrid source-driven fluence calculations. Consequently, this hybrid source-driven method can simplify and reduce cost for fast neutron fluence computations. This newly developed hybrid source-driven method should be a useful and simplified tool for computing fast neutron fluence at selected locations of interest in RPV of contemporary nuclear power reactors. (authors)

  16. Possibility of construction in Bulgaria of a fast neutron therapy center on the base of the U-250 isochronous cyclotron

    International Nuclear Information System (INIS)

    Angelov, V.A.; Enchevich, I.B.

    1985-01-01

    Development of oncological disease treatment by fast neutrons in the world practice is reviewed. Main radiobiological results, which point to peculiarities of neutron therapy in comparison with standard X-ray therapy are considered. Main requirements for devices to be met, used in fast neutron therapy, are enumerated. On the basis of it, the possibility of construction in Bulgaria a fast neutron therapy center using the U-250 multipurpose cyclotron has been made. The conclusion is made that the main parameters of a proton beam in combination with an isocentrical head as a fast neutron source will create the conditions for realization of high-efficiency neutron therapy

  17. Detection of fast neutrons with LiF and Al2O3 scintillating bolometers

    International Nuclear Information System (INIS)

    Coron, N; Gironnet, J; Leblanc, J; Marcillac, P de; Redon, T; Torres, L; Cuesta, C; Domange, J; Garcia, E; Martinez, M; Ortigoza, Y; Ortiz de Solorzano, A; Pobes, C; Puimedon, J; Rolon, T; Sarsa, M L; Villar, J A

    2010-01-01

    Scintillating bolometers of LiF and Al 2 O 3 can monitor the fast neutrons flux in WIMPs searches. With both materials we merge the traditional fast neutron detection methods of induced reactions and scattering. The ROSEBUD collaboration devoted an underground run in the old Canfranc laboratory to study the response of LiF and Al 2 O 3 to fast neutrons from 252 Cf. Both bolometers were used simultaneously in a common experimental set-up resembling those of current WIMPs searches, which could give valuable insights into future WIMPs searches with cryogenic detectors as EURECA.

  18. Development and Characterization of a High Sensitivity Segmented Fast Neutron Spectrometer (FaNS-2).

    Science.gov (United States)

    Langford, T J; Beise, E J; Breuer, H; Heimbach, C R; Ji, G; Nico, J S

    2016-01-01

    We present the development of a segmented fast neutron spectrometer (FaNS-2) based upon plastic scintillator and 3 He proportional counters. It was designed to measure both the flux and spectrum of fast neutrons in the energy range of few MeV to 1 GeV. FaNS-2 utilizes capture-gated spectroscopy to identify neutron events and reject backgrounds. Neutrons deposit energy in the plastic scintillator before capturing on a 3 He nucleus in the proportional counters. Segmentation improves neutron energy reconstruction while the large volume of scintillator increases sensitivity to low neutron fluxes. A main goal of its design is to study comparatively low neutron fluxes, such as cosmogenic neutrons at the Earth's surface, in an underground environment, or from low-activity neutron sources. In this paper, we present details of its design and construction as well as its characterization with a calibrated 252 Cf source and monoenergetic neutron fields of 2.5 MeV and 14 MeV. Detected monoenergetic neutron spectra are unfolded using a Singular Value Decomposition method, demonstrating a 5% energy resolution at 14 MeV. Finally, we discuss plans for measuring the surface and underground cosmogenic neutron spectra with FaNS-2.

  19. Development of a dual phantom technique for measuring the fast neutron component of dose in boron neutron capture therapy.

    Science.gov (United States)

    Sakurai, Yoshinori; Tanaka, Hiroki; Kondo, Natsuko; Kinashi, Yuko; Suzuki, Minoru; Masunaga, Shinichiro; Ono, Koji; Maruhashi, Akira

    2015-11-01

    Research and development of various accelerator-based irradiation systems for boron neutron capture therapy (BNCT) is underway throughout the world. Many of these systems are nearing or have started clinical trials. Before the start of treatment with BNCT, the relative biological effectiveness (RBE) for the fast neutrons (over 10 keV) incident to the irradiation field must be estimated. Measurements of RBE are typically performed by biological experiments with a phantom. Although the dose deposition due to secondary gamma rays is dominant, the relative contributions of thermal neutrons (below 0.5 eV) and fast neutrons are virtually equivalent under typical irradiation conditions in a water and/or acrylic phantom. Uniform contributions to the dose deposited from thermal and fast neutrons are based in part on relatively inaccurate dose information for fast neutrons. This study sought to improve the accuracy in the dose estimation for fast neutrons by using two phantoms made of different materials in which the dose components can be separated according to differences in the interaction cross sections. The development of a "dual phantom technique" for measuring the fast neutron component of dose is reported. One phantom was filled with pure water. The other phantom was filled with a water solution of lithium hydroxide (LiOH) capitalizing on the absorbing characteristics of lithium-6 (Li-6) for thermal neutrons. Monte Carlo simulations were used to determine the ideal mixing ratio of Li-6 in LiOH solution. Changes in the depth dose distributions for each respective dose component along the central beam axis were used to assess the LiOH concentration at the 0, 0.001, 0.01, 0.1, 1, and 10 wt. % levels. Simulations were also performed with the phantom filled with 10 wt. % 6LiOH solution for 95%-enriched Li-6. A phantom was constructed containing 10 wt. % 6LiOH solution based on the simulation results. Experimental characterization of the depth dose distributions of the

  20. On the neutronics of European lead-cooled fast reactor

    International Nuclear Information System (INIS)

    Cetnar, J.; Domanska, G.; Oettingen, M.

    2010-01-01

    The perspective of nuclear energy development in the near future imposes a new challenge on a number of sciences over the world. For years, the European Commission (EC) has sponsored scientific activities through the framework programmes (FP). The lead-cooled fast reactor (LFR) development in the European Union (EU) has been carried out within European lead-cooled system (ELSY) project of the 6 th FP of EURATOM. This paper concerns the reactor core neutronic and burn-up design studies. We discuss two different core configurations of ELSY reactor; one loaded with the reference - mixed oxide fuel (MOX), whereas the second one with an advanced fuel - uranium-plutonium nitride. Both fuels consist of reactor grade plutonium, depleted uranium and additionally, a fraction of minor actinides (MA). The fuel burn-up and the time evolution of the reactor characteristics has been assessed using a Monte Carlo burn-up code (MCB). One of the important findings concerns the importance of power profile evolution with burn-up as a limiting factor of the refuelling interval. (authors)

  1. Application of fast neutrons in the mutagenesis of peas

    International Nuclear Information System (INIS)

    Huczkowski, J.; Kubajak, A.

    1976-01-01

    Air dry seeds of two varieties of peas were irradiated with fast neutrons of average energy of 5,6 MeV obtained in the U-120 cyclotron at the Cracow Institute of Nuclear Physics. The doses varied from 60 to 1600 rads. It was found that even very low doses (less than 100 rads) cause a conspicuous delay of germination; a significant decrease of seedling height was only observed at doses higher than 200 rads. In the 170-620 rad range seedling height diminished lineraly with increase of dose. On the basis of the greenhouse experiment five doses were chosen for field experiments: 200, 300, 500, 800 and 1000 rads. It was found that a dose of about 500 rads was the maximum that could be applied for breeding purposes: the survival and fertility rate at that dose was about 40% of the control, doses of 800 to 900 rads caused full mortality. The M2 seeds were sown in the greenhouse and the frequency of chlorophyl mutations was examined in generation M2. It was found to be very high: for doses of 200 t0 300 rads the mutations ocurred in about 4% of M2 seedlings. (author)

  2. New wheat cultivars induced by fast neutrons in Iraq

    International Nuclear Information System (INIS)

    Ibrahim, I.F.; Al-Maaroof, E.M.; Al-Aubaidi, M.O.; Al-Janabi, K.K.; Al-Janabi, A.A.; Al-Rawi, L.; Ali, A.H.

    1994-01-01

    Wheat (Triticum aestivum L. ssp. aestivum) seeds from the cultivar Mexipak and F2 of the cross SaberBeg/Mexipak and saberBeg/Mexipak/Abu-Ghraib-4 were irradiated with fast neutrons and screened for resistance to leaf rust (Puccinia recondita Rob. ex Desm.) during three generations. Thirty-eight and 226 variants showing resistant and moderately resistant reactions, respectively, were selected. Of these variants three mutants showing genetic purity and stability were studied for yield components for four successive generations. Analyses of proteins and isozymes along with chemical and physical properties were conducted on these mutants and their parents. Data on disease incidence, lodging, shattering and yield components indicated that all the mutants significantly surpassed the cultivars Mexipak, SaberBeg and Abu-Ghraib-4. Both mutants Tamuz-1 and Tamuz-2 surpassed Mexipak in bread-making quality, while the mutant Tamuz-3 had a higher tendency for better bread-making quality than Mexipak or SeberBeg

  3. Clinical experience of fast neutron therapy for carcinoma of the uterine cervix

    International Nuclear Information System (INIS)

    Morita, S.; Arai, T.; Nakano, T.; Ishikawa, T.; Tsunemoto, H.; Fukuhisa, K.; Kasamatsu, T.

    1985-01-01

    Fast neutron therapy for locally advanced or radioresistant malignant tumors was started in November 1975 at the National Institute of Radiological Sciences (NIRS), Chiba, Japan. To evaluate the effectiveness of fast neutron therapy, mixed neutron-photon fractionated irradiation, on squamous cell carcinoma of the uterine cervix, 98 patients with Stage IIIb disease were examined to study the correlation between local control rate and histological types. The local control rate after neutron-mixed beam therapy was 73%, which decreased to 66% with photon irradiation. The five year survival rate was 49% for patients receiving neutron therapy and 49% for those receiving photon therapy. There was no significant difference in complications between the neutron therapy and photon therapy group

  4. Distinguishing Pu Metal from Pu Oxide and Determining alpha-ratio using Fast Neutron Counting

    Energy Technology Data Exchange (ETDEWEB)

    Verbeke, J. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chapline, G. F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Nakae, L. F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Prasad, M. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sheets, S. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Snyderman, N. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-01-07

    We describe a new method for determining the ratio of the rate of (α, n) source neutrons to the rate of spontaneous fission neutrons, the so called α-ratio. This method is made possible by fast neutron counting with liquid scintillator detectors, which can determine the shape of the fast neutron spectrum. The method utilizes the spectral difference between fission spectrum neutrons from Pu metal and the spectrum of (α, n) neutrons from PuO2. Our method is a generalization of the Cifarelli-Hage method for determining keff for fissile assemblies, and also simultaneously determines keff along with the α-ratio.

  5. Detection of fast neutrons from shielded nuclear materials using a semiconductor alpha detector.

    Science.gov (United States)

    Pöllänen, R; Siiskonen, T

    2014-08-01

    The response of a semiconductor alpha detector to fast (>1 MeV) neutrons was investigated by using measurements and simulations. A polyethylene converter was placed in front of the detector to register recoil protons generated by elastic collisions between neutrons and hydrogen nuclei of the converter. The developed prototype equipment was tested with shielded radiation sources. The low background of the detector and insensitivity to high-energy gamma rays above 1 MeV are advantages when the detection of neutron-emitting nuclear materials is of importance. In the case of a (252)Cf neutron spectrum, the intrinsic efficiency of fast neutron detection was determined to be 2.5×10(-4), whereas three-fold greater efficiency was obtained for a (241)AmBe neutron spectrum. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Conceptual study of a compact accelerator-driven neutron source for radioisotope production, boron neutron capture therapy and fast neutron therapy

    CERN Document Server

    Angelone, M; Rollet, S

    2002-01-01

    The feasibility of a compact accelerator-driven device for the generation of neutron spectra suitable for isotope production by neutron capture, boron neutron capture therapy and fast neutron therapy, is analyzed by Monte Carlo simulations. The device is essentially an extension of the activator proposed by Rubbia left bracket CERN/LHC/97-04(EET) right bracket , in which fast neutrons are diffused and moderated within a properly sized lead block. It is shown that by suitable design of the lead block, as well as of additional elements of moderating and shielding materials, one can generate and exploit neutron fluxes with the spectral features required for the above applications. The linear dimensions of the diffusing-moderating device can be limited to about 1 m. A full-scale device for all the above applications would require a fast neutron source of about 10**1**4 s**-**1, which could be produced by a 1 mA, 30 MeV proton beam impinging on a Be target. The concept could be tested at the Frascati Neutron Gener...

  7. Clinical experience in patients with Pancoast's tumor treated by fast neutron therapy

    International Nuclear Information System (INIS)

    Sawada, Kinya; Fukuma, Seigo; Seki, Yasuo

    1983-01-01

    We reveiw our results with fast neutron therapy in Pancoast's tumor, and compare them with results obtained by photon beam therapy. 13 patients with Pancoast's tumor were divided into two groups; Group I (8 patients) received fast neutron therapy. Group II (5 patients) were treated by voltage X-ray therapy. 1. Group I was comprised of 3 patients receiving mixed beam therapy (TDF 80-100) and 5 patients subjected to boost therapy. All group II patients received 3100 to 8000 rads. 2. Fast neutron therapy was effective in 7 patients. In group II, high voltage X-ray therapy was effective in only 3 patients. 3. Two group I patients are still alive without signs of recurrence. The others died with a mean survival of 11 months. All group II patients died; their mean survival was 4.2 months. Our results suggest that fast neutron therapy is suitable and effective in patients with Pancoast's tumor. (author)

  8. Analysis of some Egyptian cosmetic samples by fast neutron activation analysis

    International Nuclear Information System (INIS)

    Medhat, M.E.; Ali, M.A.; Hassan, M.F.

    2001-01-01

    A description of D-T neutron generator (NG) is presented. This generator can be used for fast neutron activation analysis applied to determine some selected elements, especially light elements, in different materials. The concentrations of the elements Na, Mg, Al, Si, K, Cl, Ca and Fe were determined in two domestic brands of face powder by using 14 MeV neutron activation analysis

  9. Analysis of Some Egyptian Cosmetic Samples by Fast Neutron Activation Analysis

    CERN Document Server

    Medhat, M E; Fayez-Hassan, M

    2001-01-01

    A description of D-T neutron generator (NG) is presented. This generator can be used for fast neutron activation analysis applied to determine some selected elements, especially light elements, in different materials. In our work, the concentration of the elements Na, Mg, Al, Si, K, Cl, Ca and Fe, were determined in two domestic brands of face powder by using 14 MeV neutron activation analysis.

  10. A two-dimensional simulator of the neutronic behaviour of low power fast reactors

    International Nuclear Information System (INIS)

    Penha, M.A.V.R. da.

    1984-01-01

    A model to simulate the temporal neutronic behaviour of fast breeder reactors was developed. The effective cross-sections are corrected, whenever the reactor state change; by using linear correlations and interpolation schemes with data contained in a library previously compiled. This methodology was coupled with a simplified spatial neutronic calculation to investigate the temporal behaviour of neutronic parameters such as breeding gain, flux and power. (Author) [pt

  11. Measurements of thermal and fast neutron fluxes at the TRIGA reactor

    International Nuclear Information System (INIS)

    Zerdin, F.; Grabovsek, Z.; Klinc, T.; Solinc, H.

    1966-01-01

    Gold foils were placed at different positions in the TRIGA reactor core and in the experimental devices. Absolute values of the thermal neutron flux at these positions were obtained by coincidence method. Preliminary fast neutron spectrum was measured by threshold detector and by 'Li 6 sandwich' detector. A short description of the applied method and obtained measurements results are included [sl

  12. The fluence research of filter material for fast neutron fluence measurement

    International Nuclear Information System (INIS)

    Tang Xiding

    2010-01-01

    When the fast neutron fluence is measured by radioactivation techniques in the nuclear reactor the fast neutron is also filtered a little by the thermal neutron filter material, and if the filter material thickness increase the filtered fast neutron increases therewith. For fast neutron fluenc measurement, there are only cadmium, boron and gadolinium three elements filtering fluence can be calculated ordinarily. In order to calculate the filtered fast neutron fluence of the all elements in the filter material, the many total cross sections of nuclides had checked out from nuclear cross section data library, converted them into the same energy group structure, then element's total cross section, compound's total cross section and multilayer filters' total cross section had calculated from these total cross sections with same energy group structure, a new cross section data library can be obtained lastly through merging these cross sections into the old cross section data library used for neutron fluence measurement. The calculation analysis indicates that the results of the unit 2 surveillance capsule U of DAYA Bay NPP and the unit 1 surveillance capsule A of the Second Nuclear Power Plant of Qinshan by considering the all elements subtracting iron are smaller about 1.5% and 2.6% respectively than the ones only to consider cadmium, boron. The old measured results accord with the new values under the measurement uncertainty, are reliable. The new results are more accuracy. (authors)

  13. A fast-neutron detection detector based on fission material and large sensitive 4H silicon carbide Schottky diode detector

    Science.gov (United States)

    Liu, Linyue; Liu, Jinliang; Zhang, Jianfu; Chen, Liang; Zhang, Xianpeng; Zhang, Zhongbing; Ruan, Jinlu; Jin, Peng; Bai, Song; Ouyang, Xiaoping

    2017-12-01

    Silicon carbide radiation detectors are attractive in the measurement of the total numbers of pulsed fast neutrons emitted from nuclear fusion and fission devices because of high neutron-gamma discrimination and good radiation resistance. A fast-neutron detection system was developed based on a large-area 4H-SiC Schottky diode detector and a 235U fission target. Excellent pulse-height spectra of fission fragments induced by mono-energy deuterium-tritium (D-T) fusion neutrons and continuous energy fission neutrons were obtained. The detector is proven to be a good candidate for pulsed fast neutron detection in a complex radiation field.

  14. Measurement and evaluation of fast neutron flux of CT and OR5 irradiation hole in HANARO

    International Nuclear Information System (INIS)

    Yang, Seong Woo; Choo, Kee Nam; Lee, Seung-Kyu; Kim, Yong Kyun

    2012-01-01

    The irradiation test has been conducted to evaluate the irradiation performance of many materials by a material capsule at HANARO. Since the fast neutron fluence above 1 MeV is important for the irradiation test of material, it must be measured and evaluated exactly at each irradiation hole. Therefore, a fast neutron flux was measured and evaluated by a 09M-02K capsule irradiated in an OR5 irradiation hole and a 10M-01K capsule irradiated in a CT irradiation hole. Fe, Ni, and Ti wires as the fluence monitor were used for the detection of fast neutron flux. Before the irradiation test, the neutron flux and spectrum was calculated for each irradiation hole using an MCNP code. After the irradiation test, the activity of the fluence monitor was measured by an HPGe detector and the reaction rate was calculated. For the OR5 irradiation hole, the radial difference of the fast neutron flux was observed from a calculated data due to the OR5 irradiation hole being located outside the core. Furthermore, a control absorber rod was withdrawn from the core as the increase of the irradiation time at the same irradiation cycle, so the distribution of neutron flux was changed from the beginning to the end of the cycle. These effects were considered to evaluate the fast neutron flux. Neutron spectrums of the CT and OR5 irradiation hole were adjusted by the measured data. The fluxes of a fast neutron above 1 MeV were compared with calculated and measured value. Although the maximum difference was shown at 18.48%, most of the results showed good agreement. (author)

  15. Fission signal detection using helium-4 gas fast neutron scintillation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, J. M., E-mail: lewisj@ufl.edu; Kelley, R. P.; Jordan, K. A. [Nuclear Engineering Program, University of Florida, Gainesville, Florida 32611 (United States); Murer, D. [Arktis Radiation Detectors Ltd., 8045 Zurich (Switzerland)

    2014-07-07

    We demonstrate the unambiguous detection of the fission neutron signal produced in natural uranium during active neutron interrogation using a deuterium-deuterium fusion neutron generator and a high pressure {sup 4}He gas fast neutron scintillation detector. The energy deposition by individual neutrons is quantified, and energy discrimination is used to differentiate the induced fission neutrons from the mono-energetic interrogation neutrons. The detector can discriminate between different incident neutron energies using pulse height discrimination of the slow scintillation component of the elastic scattering interaction between a neutron and the {sup 4}He atom. Energy histograms resulting from this data show the buildup of a detected fission neutron signal at higher energies. The detector is shown here to detect a unique fission neutron signal from a natural uranium sample during active interrogation with a (d, d) neutron generator. This signal path has a direct application to the detection of shielded nuclear material in cargo and air containers. It allows for continuous interrogation and detection while greatly minimizing the potential for false alarms.

  16. Fission signal detection using helium-4 gas fast neutron scintillation detectors

    Science.gov (United States)

    Lewis, J. M.; Kelley, R. P.; Murer, D.; Jordan, K. A.

    2014-07-01

    We demonstrate the unambiguous detection of the fission neutron signal produced in natural uranium during active neutron interrogation using a deuterium-deuterium fusion neutron generator and a high pressure 4He gas fast neutron scintillation detector. The energy deposition by individual neutrons is quantified, and energy discrimination is used to differentiate the induced fission neutrons from the mono-energetic interrogation neutrons. The detector can discriminate between different incident neutron energies using pulse height discrimination of the slow scintillation component of the elastic scattering interaction between a neutron and the 4He atom. Energy histograms resulting from this data show the buildup of a detected fission neutron signal at higher energies. The detector is shown here to detect a unique fission neutron signal from a natural uranium sample during active interrogation with a (d, d) neutron generator. This signal path has a direct application to the detection of shielded nuclear material in cargo and air containers. It allows for continuous interrogation and detection while greatly minimizing the potential for false alarms.

  17. Fast neutron dosimetry by means of different solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Spurny, F.; Turek, K.

    1977-01-01

    The comparative study of three different types of fast neutron dosimeters based on solid state nuclear track detectors is presented; the dosimeters studied were: - microscopic soda glass in contact with 232 Th; - polycarbonate Makrofol E; and - cellulose nitrate Kodak LR 115. All detectors were evaluated by visual counting in a microscope. The authors have studied such properties as the background, angular as well as energetical dependences of detectors. The results obtained show that all studied detectors are suitable for fast neutron dosimetry; their application depends however on the concrete experimental conditions (neutron spectrum, fluence etc.). Both advantages and disadvantages of each of them are presented. (Auth.)

  18. Study on beam geometry and image reconstruction algorithm in fast neutron computerized tomography at NECTAR facility

    Energy Technology Data Exchange (ETDEWEB)

    Guo, J. [State Key Laboratory of Nuclear Physics and Technology and School of Physics, Peking University, 5 Yiheyuan Lu, Beijing 100871 (China); Lehrstuhl fuer Radiochemie, Technische Universitaet Muenchen, Garching 80748 (Germany); Buecherl, T. [Lehrstuhl fuer Radiochemie, Technische Universitaet Muenchen, Garching 80748 (Germany); Zou, Y., E-mail: zouyubin@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology and School of Physics, Peking University, 5 Yiheyuan Lu, Beijing 100871 (China); Guo, Z. [State Key Laboratory of Nuclear Physics and Technology and School of Physics, Peking University, 5 Yiheyuan Lu, Beijing 100871 (China)

    2011-09-21

    Investigations on the fast neutron beam geometry for the NECTAR facility are presented. The results of MCNP simulations and experimental measurements of the beam distributions at NECTAR are compared. Boltzmann functions are used to describe the beam profile in the detection plane assuming the area source to be set up of large number of single neutron point sources. An iterative algebraic reconstruction algorithm is developed, realized and verified by both simulated and measured projection data. The feasibility for improved reconstruction in fast neutron computerized tomography at the NECTAR facility is demonstrated.

  19. Preliminary research on measuring grease in petroleum pipeline using fast neutron transmission method

    International Nuclear Information System (INIS)

    Liu Qingwei; Liu Shengkang; Zhang Zhiping; Ding Xiaoping

    2006-01-01

    The principle, experiment and conclusion on the grease stain measurement using fast neutron are reported. The experiment equipment consist of 241 Am-Be fast neutron source, ZnS detector and BH1224 multichannel spectrometer. Paraffin is used instead of real grease stain. Steel plates are used instead of pipeline. The results of the experiment indicate that there is a good linearship between the logarithm of the reciprocal of the neutron transmissivity and the paraffin thickness. The measuring accuracy of the paraffin thickness is 0.6 mm in this experiment. (authors)

  20. 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...

  1. Pathologic effects of fractionated fast neutrons or photons on the pancreas, pylorus and duodenum of dogs

    International Nuclear Information System (INIS)

    Zook, B.C.; Bradley, E.W.; Casarett, G.W.; Rogers, C.C.

    1983-01-01

    Thirty-nine adult male Beagles received either fast neutron or photon irradiation to the right thorax to determine the relative biological effectiveness (RBE) of fast neutrons on normal pulmonary tissue. The right anterior abdomen was included in the field of radiation. Twenty-four dogs (six/group) received fast neutrons with an average energy of 15 MeV to total doses of 1000, 1500, 2250 or 3375 rad in four fractions per week for six weeks. Fifteen dogs received 3000, 4500, or 6750 rad of photons (five/group) in an identical fractionation pattern. All neutron irradiated dogs receiving 3375 and 2250 rad and one receiving 1500 rad developed clinical signs of pancreatic, hepatic and gastrointestinal disturbances. The liver enzymes of these dogs became elevated and they died or were euthanized in extremis 47-367 days after irradiation. Only one 6750 rad photon dog developed similar signs and died 708 days post-irradiation. Five neutron and 10 photon exposed dogs died of other causes. Neutron-induced lesions in the stomach and duodenum included hemorrhages, erosions, ulcerations and fibrosis. Ulcers perforated the GI tract of five dogs. Pancreatic lesions included degranulation and necrosis of acinar cells, fibrosis and atrophy. Islet cells were not obviously damaged. All lesions were associated with degenerative and occlusive vascular changes. The RBE of fast neutrons, assessed by clinical signs, gross and microscopic pathology, is approximately 3-4.5 for pancreas and about 4.5 for pylorus and duodenum

  2. [Dosimetry of fast neutrons in 1W nuclear reactor with plastic nuclear-track detectors].

    Science.gov (United States)

    Yasubuchi, S; Hoshi, M; Itoh, T; Hisanaga, S; Niwa, T; Miki, R; Kondo, S

    1989-09-01

    A nuclear reactor at Kinki University is operated at the maximum of 1W. It produces fission neutrons as much as gamma-rays. To facilitate its use for neutron radiobiology, fast neutrons inside the reactor were measured with nuclear-track detectors TS 16 N and a pair of ion chambers. The angular dependence of TS 16 N response, an anisotropy of fast neutron fluxes in the reactor and misuse of the kerma factor assumed for radiation protection business are the major causes of discrepancy is measured doses by the two methods. Correction factors for the three causes are proposed. After correction, neutron doses estimated with TS 16 N and chambers agree within 5%. The dose-rate at the reactor's center is about 20 tissue-cGy/h. This is the first in situ dosimetry of fast neutrons in a reactor with track detectors attached to biologic samples. Our routine usage has demonstrated that, if used with caution, TS 16 N elements are handy, reliable monitors for fast neutron dosimetry as they are insensitive to contaminated gamma-rays and small enough to be attached to biologic samples.

  3. Standard Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of Iron

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    DESIG: E 263 09 ^TITLE: Standard Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of Iron ^SIGNUSE: Refer to Guide E 844 for guidance on the selection, irradiation, and quality control of neutron dosimeters. Refer to Practice E 261 for a general discussion of the determination of fast-neutron fluence rate with threshold detectors. Pure iron in the form of foil or wire is readily available and easily handled. Fig. 1 shows a plot of cross section as a function of neutron energy for the fast-neutron reaction 54Fe(n,p)54Mn (1). This figure is for illustrative purposes only to indicate the range of response of the 54Fe(n,p)54Mn reaction. Refer to Guide E 1018 for descriptions of recommended tabulated dosimetry cross sections. 54Mn has a half-life of 312.13 days (3) (2) and emits a gamma ray with an energy of 834.845 keV (5). (2) Interfering activities generated by neutron activation arising from thermal or fast neutron interactions are 2.57878 (46)-h 56Mn, 44.95-d (8) 59Fe, and 5.27...

  4. Fast-neutron-induced fission of 242Pu at nELBE

    Directory of Open Access Journals (Sweden)

    Kögler Toni

    2017-01-01

    Full Text Available The fast neutron-induced fission cross section of 242Pu was determined in the range of 0.5 MeV to 10 MeV relative to 235U(n,f at the neutron time-of-flight facility nELBE. The number of target nuclei was calculated by means of measuring the spontaneous fission rate of 242Pu. Neutron transport simulations with Geant4 and MCNP6 are used to correct the relative cross section for neutron scattering. The determined results are in good agreement with current experimental and evaluated data sets.

  5. Inelastic scattering of fast neutrons on Fe-56; Inelastische Streuung schneller Neutronen an {sup 56}Fe

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, Roland

    2014-11-24

    The relevant reaction cross sections for the nuclear transmutation will be measured at the neutron flight time facility nELBE in Dresden-Rossendorf. Transmutation by fast neutron irradiation is supposed to reduce the radiotoxicity of high-level radioactive wastes. The thesis is aimed to measure the inelastic neutron scattering cross sections of Fe-56 using a new double flight-time method. With combined plastic and BaF2 scintillation detectors for the first time the emitted neutrons and photons are observed in coincidence.

  6. MCNPX simulations of fast neutron diagnostics for accelerator-driven systems

    International Nuclear Information System (INIS)

    Habib, Moinul

    2005-12-01

    In accelerator-driven systems, the neutron spectrum will extend all the way up to the incident beam energy, i.e., several hundred MeV or even up to GeV energies. The high neutron energy allows novel diagnostics with a set of measurement techniques that can be used in a sub-critical reactor environment. Such measurements are primarily connected to system safety and validation. This report shows that in-core fast-neutron diagnostics can be employed to monitor changes in the position of incidence of the primary proton beam onto the neutron production target. It has also been shown that fast neutrons can be used to detect temperature-dependent density changes in a liquid lead-bismuth target. Fast neutrons can escape the system via the beam pipe for the incident proton beam. Out-of-core monitoring of these so called back-streaming neutrons could potentially be used to monitor beam changes if the target has a suitable shape. Moreover, diagnostics of back-streaming neutrons might be used for validation of the system design

  7. Fast neutron flux analyzer with real-time digital pulse shape discrimination

    Science.gov (United States)

    Ivanova, A. A.; Zubarev, P. V.; Ivanenko, S. V.; Khilchenko, A. D.; Kotelnikov, A. I.; Polosatkin, S. V.; Puryga, E. A.; Shvyrev, V. G.; Sulyaev, Yu. S.

    2016-08-01

    Investigation of subthermonuclear plasma confinement and heating in magnetic fusion devices such as GOL-3 and GDT at the Budker Institute (Novosibirsk, Russia) requires sophisticated equipment for neutron-, gamma- diagnostics and upgrading data acquisition systems with online data processing. Measurement of fast neutron flux with stilbene scintillation detectors raised the problem of discrimination of the neutrons (n) from background cosmic particles (muons) and neutron-induced gamma rays (γ). This paper describes a fast neutron flux analyzer with real-time digital pulse-shape discrimination (DPSD) algorithm FPGA-implemented for the GOL-3 and GDT devices. This analyzer was tested and calibrated with the help of 137Cs and 252Cf radiation sources. The Figures of Merit (FOM) calculated for different energy cuts are presented.

  8. Fast neutron personnel dosimetry by CR-39 plastics a new electrochemical etching procedure

    International Nuclear Information System (INIS)

    Djeffal, S.

    1984-07-01

    In the first part of this work a brief description of solid state nuclear track detectors, the principles of track registration and the different reading techniques are given. In the experimental part of the present work we systematically analysed different etching procedures and set a new electrochemical etching method, which enables us to develop a new fast neutron dosimeter. This fast neutron dosimeter makes possible the measurement of low neutron doses in the energy range from 10 Kev to 20 Mev with a reasonably flat energy response. These new developments are very attractive in personnel neutron dosimetry where nuclear emulsions are still used despite their insensitivity to neutron energies down to 500 Kev (i.e. the energy range one often encounters around nuclear facilities)

  9. Removal cross sections and total mass attenuation coefficients of fast neutrons and gamma rays for steel

    CERN Document Server

    Elsayed, A A

    2003-01-01

    The present work deals with the study of the attenuation properties and determination of the cross sections of fast neutrons and gamma rays for structure steel used in different applications in nuclear power plants, particle accelerators, research reactors and different radiation attenuation fields. Investigation has been performed by measuring the transmitted fast neutron and gamma ray spectra behind cylindrical samples of steel (rho=7.87 gem sup - sup 3) of different thicknesses. A reactor collimated beam and neutron - gamma spectrometer with stiblbene scintillator were used for measurements. The pluse shape disriminate technique based on zero cross over method was used to discriminate between neutron and gamma ray pulses. Effective removal cross-section (sigma sub R) and total mass attenuation coefficient (mu) of neureons and gamma rays have been achieved using the attenuation relations. Microscopic removal cross sections sigma sup 9 sup 8 and mass removal cross sections sigma sub R sub / subrho of fast ne...

  10. Fast-Neutron Spectrometry Using a 3He Ionization Chamber and Digital Pulse Shape Analysis

    Energy Technology Data Exchange (ETDEWEB)

    D. L. Chichester; J. T. Johnson; E. H. Seabury

    2010-05-01

    Digital pulse shape analysis (dPSA) has been used with a Cuttler-Shalev type 3He proportional counter to measure the fast neutron spectra of bare 252Cf and 241AmBe neutron sources. Measurements have also been made to determine the attenuated fast neutron spectra of 252Cf shielded by several materials including water, graphite, liquid nitrogen, magnesium, and tungsten. Rise-time dPSA has been employed using the common rise-time approach for analyzing n +3He ? 1H + 3H ionization events and a new approach has been developed to improve the fidelity of these measurements. Simulations have been performed for the different experimental arrangements and are compared, demonstrating general agreement between the dPSA processed fast neutron spectra and predictions.

  11. A calibrated 6Li glass detector for fast neutrons. Description and use

    International Nuclear Information System (INIS)

    Le Rigoleur, Claude.

    1976-10-01

    A fast neutron detector which efficiency has been carefully measured is described. The time response of this detector is better than 1.2 nanosecond. This detector is used with fast-time-of-flight technique. Its efficiency is known within 2.5% between 5 and 180keV and within 5% between 300 and 1200keV [fr

  12. In-Pile Qualification of the Fast-Neutron-Detection-System

    Science.gov (United States)

    Fourmentel, D.; Villard, J.-F.; Destouches, C.; Geslot, B.; Vermeeren, L.; Schyns, M.

    2018-01-01

    In order to improve measurement techniques for neutron flux assessment, a unique system for online measurement of fast neutron flux has been developed and recently qualified in-pile by the French Alternative Energies and Atomic Energy Commission (CEA) in cooperation with the Belgian Nuclear Research Centre (SCK•ECEN). The Fast-Neutron-Detection-System (FNDS) has been designed to monitor accurately high-energy neutrons flux (E > 1 MeV) in typical Material Testing Reactor conditions, where overall neutron flux level can be as high as 1015 n.cm-2.s-1 and is generally dominated by thermal neutrons. Moreover, the neutron flux is coupled with a high gamma flux of typically a few 1015 γ.cm-2.s-1, which can be highly disturbing for the online measurement of neutron fluxes. The patented FNDS system is based on two detectors, including a miniature fission chamber with a special fissile material presenting an energy threshold near 1 MeV, which can be 242Pu for MTR conditions. Fission chambers are operated in Campbelling mode for an efficient gamma rejection. FNDS also includes a specific software that processes measurements to compensate online the fissile material depletion and to adjust the sensitivity of the detectors, in order to produce a precise evaluation of both thermal and fast neutron flux even after long term irradiation. FNDS has been validated through a two-step experimental program. A first set of tests was performed at BR2 reactor operated by SCK•CEN in Belgium. Then a second test was recently completed at ISIS reactor operated by CEA in France. FNDS proved its ability to measure online the fast neutron flux with an overall accuracy better than 5%.

  13. Technical Meeting on Existing and Proposed Experimental Facilities for Fast Neutron Systems. Presentations

    International Nuclear Information System (INIS)

    2013-01-01

    The objective of the TM on “Existing and proposed experimental facilities for fast neutron systems” is threefold: first, it is intended for presenting and exchanging information about existing and planned experimental facilities in support of the development of innovative fast neutron systems; second, it will allow to create a catalogue of existing and planned experimental facilities currently operated/developed within national or international fast reactors programmes; third, once a clear picture of the existing experimental infrastructures is defined, new experimental facilities will be discussed and proposed, on the basis of the identified R&D needs

  14. Technical Meeting on Existing and Proposed Experimental Facilities for Fast Neutron Systems. Working Material

    International Nuclear Information System (INIS)

    2013-01-01

    The objective of the TM on “Existing and proposed experimental facilities for fast neutron systems” was threefold: 1) presenting and exchanging information about existing and planned experimental facilities in support of the development of innovative fast neutron systems; 2) allow creating a catalogue of existing and planned experimental facilities currently operated/developed within national or international fast reactors programmes; 3) once a clear picture of the existing experimental infrastructures is defined, new experimental facilities are discussed and proposed, on the basis of the identified R&D needs

  15. Fast neutron therapy at the end of 1988 - a survey of the clinical data

    International Nuclear Information System (INIS)

    Wambersie, A.

    1990-01-01

    The clinical results reported from the different neutron therapy centres, in USA, Europe and Asia, are reviewed. Fast neutrons were proven to be superior to photons for locally extended inoperable salivary gland tumours. The reported overall local control rates are 67% and 24% respectively. Paranasal sinuses and some tumours of the head and neck area, especially extended tumours with large fixed lymph nodes, are also indications for neutrons. By contrast, the results obtained for brain tumours were, in general, disappointing. Neutrons were shown to bring a benefit in the treatment of well differentiated slowly growing soft tissue sarcomas. The reported overall local control rates are 53% and 38% after neutron and photon irradiation respectively. Better results were also reported for bone- and chondrosarcomas. The reported local control rates are 54% for osteosarcomas and 49% for chondrosarcomas after neutron irradiation; the corresponding values are 21% and 33% respectively after photon irradiation. For locally extended prostatic adenocarcinoma, the superiority of mixed schedule (neutrons+photons) was demonstrated by a RTOG randomized trial (local control rates 77% for mixed schedule compared to 31% for photons). Neutrons were also shown to be useful for palliative treatment of melanomas. Further studies are needed in order to evaluate the benefit of fast neutrons for other localisations such as cervix, bladder, rectum. It can be concluded that fast neutrons are superior to photons for at least 10% of the radiotherapy patients. It is likely that the new high-energy hospital-based cyclotron will further extend the indications of neutron therapy. However, patient selection remains one of the main problems and there is a need for development of individual predictive tests. (orig.)

  16. Reactions with fast radioactive beams of neutron-rich nuclei

    International Nuclear Information System (INIS)

    Aumann, T.

    2005-11-01

    The neutron dripline has presently been reached only for the lightest nuclei up to the element oxygen. In this region of light neutron-rich nuclei, scattering experiments are feasible even for dripline nuclei by utilizing high-energy secondary beams produced by fragmentation. In the present article, reactions of high-energy radioactive beams will be exemplified using recent experimental results mainly derived from measurements of breakup reactions performed at the LAND and FRS facilities at GSI and at the S800 spectrometer at the NSCL. Nuclear and electromagnetically induced reactions allow probing different aspects of nuclear structure at the limits of stability related to the neutron-proton asymmetry and the weak binding close to the dripline. Properties of the valence-neutron wave functions are studied in the one-neutron knockout reaction, revealing the changes of shell structure when going from the beta-stability line to more asymmetric loosely bound neutron-rich systems. The vanishing of the N=8 shell gap for neutron-rich systems like 11 Li and 12 Be, or the new closed N=14, 16 shells for the oxygen isotopes are examples. The continuum of weakly bound nuclei and halo states can be studied by inelastic scattering. The dipole response, for instance, is found to change dramatically when going away from the valley of stability. A redistribution of the dipole strength towards lower excitation energies is observed for neutron-rich nuclei, which partly might be due to a new collective excitation mode related to the neutron-proton asymmetry. Halo nuclei in particular show strong dipole transitions to the continuum at the threshold, being directly related to the ground-state properties of the projectile. Finally, an outlook on future experimental prospects is given. (orig.)

  17. Reactions with fast radioactive beams of neutron-rich nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Aumann, T. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)

    2005-11-01

    The neutron dripline has presently been reached only for the lightest nuclei up to the element oxygen. In this region of light neutron-rich nuclei, scattering experiments are feasible even for dripline nuclei by utilizing high-energy secondary beams produced by fragmentation. In the present article, reactions of high-energy radioactive beams will be exemplified using recent experimental results mainly derived from measurements of breakup reactions performed at the LAND and FRS facilities at GSI and at the S800 spectrometer at the NSCL. Nuclear and electromagnetically induced reactions allow probing different aspects of nuclear structure at the limits of stability related to the neutron-proton asymmetry and the weak binding close to the dripline. Properties of the valence-neutron wave functions are studied in the one-neutron knockout reaction, revealing the changes of shell structure when going from the beta-stability line to more asymmetric loosely bound neutron-rich systems. The vanishing of the N=8 shell gap for neutron-rich systems like {sup 11}Li and {sup 12}Be, or the new closed N=14, 16 shells for the oxygen isotopes are examples. The continuum of weakly bound nuclei and halo states can be studied by inelastic scattering. The dipole response, for instance, is found to change dramatically when going away from the valley of stability. A redistribution of the dipole strength towards lower excitation energies is observed for neutron-rich nuclei, which partly might be due to a new collective excitation mode related to the neutron-proton asymmetry. Halo nuclei in particular show strong dipole transitions to the continuum at the threshold, being directly related to the ground-state properties of the projectile. Finally, an outlook on future experimental prospects is given. (orig.)

  18. Fast radio bursts and their possible neutron star origins

    Science.gov (United States)

    Hessels, J. W. T.

    2017-12-01

    The discovery of the ‘Lorimer Burst’, a little over a decade ago, ignited renewed interest in searching for short-duration radio transients (Lorimer et al 2007 Science 318 777). This event is now considered to be the first established Fast Radio Burst (FRB), which is a class of millisecond-duration radio transients (Thornton et al 2013 Science 341 53). The large dispersive delays observed in FRBs distinguish them from the individual bright pulses from Galactic pulsars, and suggests that they originate deep in extragalactic space. Amazingly, FRBs are not rare: the implied event rate ranges up to many thousands of events per sky, per day (Champion et al 2016 MNRAS 460 L30). The fact that only two dozen FRBs have been discovered to date is a consequence of the limited sensitivity and field of view of current radio telescopes (Petroff et al 2016 PASA 33 e045). The precise localization of FRB 121102, the first and currently only FRB observed to repeat (Spitler et al 2014 ApJ 790 101; Spitler et al 2016 Nature 531 202; Scholz et al 2016 ApJ 833 177), has led to the unambiguous identification of its host galaxy and thus proven its extragalactic origin and large energy scale (Chatterjee et al 2017 Nature 541 58; Tendulkar et al 2017 ApJL 834 L7; Marcote et al 2017 ApJL 834 L8). It remains unclear, however, whether all FRBs are capable of repeating [many appear far less active (Petroff et al 2015 MNRAS 454 457)] or whether FRB 121102 implies that there are multiple sub-classes. Regardless, the repetitive nature of FRB 121102 and its localization to within a star-forming region in the host galaxy (Bassa et al 2017 ApJL 843 L8) imply that the bursts might originate from an exceptionally powerful neutron star - one necessarily quite unlike any we have observed in the Milky Way. In these proceedings, I give a very brief introduction to the FRB phenomenon and focus primarily on the insights that FRB 121102 has provided thus far.

  19. Unfolding the fast neutron spectra of a BC501A liquid scintillation detector using GRAVEL method

    Science.gov (United States)

    Chen, YongHao; Chen, XiMeng; Lei, JiaRong; An, Li; Zhang, XiaoDong; Shao, JianXiong; Zheng, Pu; Wang, XinHua

    2014-10-01

    Accurate knowledge of the neutron energy spectra is useful in basic research and applications. The overall procedure of measuring and unfolding the fast neutron energy spectra with BC501A liquid scintillation detector is described. The recoil proton spectrum of 241Am-Be neutrons was obtained experimentally. With the NRESP7 code, the response matrix of detector was simulated. Combining the recoil proton spectrum and response matrix, the unfolding of neutron spectra was performed by GRAVEL iterative algorithm. A MatLab program based on the GRAVEL method was developed. The continuous neutron spectrum of 241Am-Be source and monoenergetic neutron spectrum of D-T source have been unfolded successfully and are in good agreement with their standard reference spectra. The unfolded 241Am-Be spectrum are more accurate than the spectra unfolded by artificial neural networks in recent years.

  20. Effect of Gamma Rays on Fast Neutron Registration in CR-39

    CERN Document Server

    Kobzev, A P; El-Halem, A A; Abdul-Ghaphar, U S; Salama, T A

    2002-01-01

    A set of CR-39 plastic detectors with front PE radiator was exposed to Am-Be neutron source, which has an emission rate of 0.86\\cdot 10^{7} sec^{-1}, and the neutron dose equivalent rate 1 m apart from the source is equal to 11 mrem/hr. Another set of samples was irradiated by a neutron dose of 4 rem, then exposed to different gamma-ray doses using ^{60}Co source. It was found that the track density grows with the increase of neutron dose and etching time. It was also found that the bulk etching rate V_{B}, the track diameter and the sensitivity of the CR-39 plastic detector with respect to the neutron irradiation increased with increasing gamma-ray dose in the range 1?10 Mrad. These results show that CR-39 can be considered as a promising fast neutron dosimeter and gamma-ray dosimeter.

  1. Study of the propagation of fast neutrons in water, by Monte-Carlo methods

    International Nuclear Information System (INIS)

    Lafore, P.; Lattes, R.; Millot, J.P.

    1958-01-01

    We have studied the propagation in water of neutrons from mono-directional plane sources with energies ranging from 300 keV to 19,66 MeV, placed in an infinite water medium. The exact paths of a number of neutrons are determined, taking into account the microscopic sections, assuming that inelastic collisions of the neutrons on oxygen are absorptions, and neglecting the loss of energy by elastic collisions on oxygen. The neutron lifetimes have been made use of to study the propagation of neutrons from fission sources, Po-Be, Po-B and Ra-Be, as well as the reflection of fast neutrons on a semi-infinite water medium. We have taken complete account of the first collision in order to improve the precision of the results. The calculations were carried out by Mrs J. VASSEUR and Mr A. GUILLOU. (author) [fr

  2. Direct mass measurements of light neutron-rich nuclei using fast recoil spectrometers

    International Nuclear Information System (INIS)

    Vieira, D.J.; Wouters, J.M.

    1987-01-01

    Extensive new mass measurement capabilities have evolved with the development of recoil spectrometers. In the Z = 3 to 9 neutron-rich region alone, 12 neutron-rich nuclei have been determined for the first time by the fast-recoil direct mass measurement method. A recent experiment using the TOFI spectrometer illustrates this technique. A systematic investigation of nuclei that lie along or near the neutron-drip line has provided a valuable first glimpse into the nuclear structure of such nuclei. No evidence for a large single-particle energy gap at N = 14 is observed; however, a change in the two-neutron separation model calculations, and is interpreted in terms of the smaller 1s/sub 1/2/ - 1s/sub 1/2/ interaction compared to that of the 0d/sub 5/2/ - 0d/sub 5/2/ neutron-neutron interaction. 18 refs., 7 figs., 1 tab

  3. Qualification and characterization of electronics of the fast neutron Hodoscope detectors using neutrons from CABRI core

    Science.gov (United States)

    Mirotta, S.; Guillot, J.; Chevalier, V.; Biard, B.

    2018-01-01

    The study of Reactivity Initiated Accidents (RIA) is important to determine up to which limits nuclear fuels can withstand such accidents without clad failure. The CABRI International Program (CIP), conducted by IRSN under an OECD/NEA agreement, has been launched to perform representative RIA Integral Effect Tests (IET) on real irradiated fuel rods in prototypical Pressurized Water Reactors (PWR) conditions. For this purpose, the CABRI experimental pulse reactor, operated by CEA in Cadarache, France, has been strongly renovated, and equipped with a pressurized water loop. The behavior of the test rod, located in that loop in the center of the driver core, is followed in real time during the power transients thanks to the hodoscope, a unique online fuel motion monitoring system, and one of the major distinctive features of CABRI. The hodoscope measures the fast neutrons emitted by the tested rod during the power pulse with a complete set of 153 Fission Chambers and 153 Proton Recoil Counters. During the CABRI facility renovation, the electronic chain of these detectors has been upgraded. In this paper, the performance of the new system is presented describing gain calibration methodology in order to get maximal Signal/Noise ratio for amplification modules, threshold tuning methodology for the discrimination modules (old and new ones), and linear detectors response limit versus different reactor powers for the whole electronic chain.

  4. Qualification and characterization of electronics of the fast neutron Hodoscope detectors using neutrons from CABRI core

    Directory of Open Access Journals (Sweden)

    Mirotta S.

    2018-01-01

    Full Text Available The study of Reactivity Initiated Accidents (RIA is important to determine up to which limits nuclear fuels can withstand such accidents without clad failure. The CABRI International Program (CIP, conducted by IRSN under an OECD/NEA agreement, has been launched to perform representative RIA Integral Effect Tests (IET on real irradiated fuel rods in prototypical Pressurized Water Reactors (PWR conditions. For this purpose, the CABRI experimental pulse reactor, operated by CEA in Cadarache, France, has been strongly renovated, and equipped with a pressurized water loop. The behavior of the test rod, located in that loop in the center of the driver core, is followed in real time during the power transients thanks to the hodoscope, a unique online fuel motion monitoring system, and one of the major distinctive features of CABRI. The hodoscope measures the fast neutrons emitted by the tested rod during the power pulse with a complete set of 153 Fission Chambers and 153 Proton Recoil Counters. During the CABRI facility renovation, the electronic chain of these detectors has been upgraded. In this paper, the performance of the new system is presented describing gain calibration methodology in order to get maximal Signal/Noise ratio for amplification modules, threshold tuning methodology for the discrimination modules (old and new ones, and linear detectors response limit versus different reactor powers for the whole electronic chain.

  5. Neutron Collar Evolution and Fresh PWR Assembly Measurements with a New Fast Neutron Passive Collar

    Energy Technology Data Exchange (ETDEWEB)

    Menlove, Howard Olsen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Geist, William H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Root, Margaret A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rael, Carlos D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Belian, Anthony P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-11-02

    The passive neutron collar approach removes the effect of poison rods when using a 1mm Gd liner. This project sets out to solve the following challenges: BWR fuel assemblies have less mass and less neutron multiplication than PWR; and effective removal of cosmic ray spallation neutron bursts needed via QC tests.

  6. Microdosimetric investigations at the fast neutron therapy facility at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Langen, K.M.

    1997-12-01

    Microdosimetry was used to investigate three issues at the neutron therapy facility (NTF) at Fermilab. Firstly, the conversion factor from absorbed dose in A-150 tissue equivalent plastic to absorbed dose in ICRU tissue was determined. For this, the effective neutron kerma factor ratios, i.e., oxygen tissue equivalent plastic and carbon to A-150 tissue equivalent plastic, were measured in the neutron beam. An A-150 tissue equivalent plastic to ICRU tissue absorbed dose conversion factor of 0.92 {+-} 0.04 was determined. Secondly, variations in the radiobiological effectiveness (RBE) in the beam were mapped by determining variations in two related quantities, e{sup *} and R, with field size and depth in tissue. Maximal variation in e{sup *} and R of 9% and 15% respectively were determined. Lastly, the feasibility of utilizing the boron neutron capture reaction on boron-10 to selectively enhance the tumor dose in the NTF beam was investigated.

  7. Microdosimetric investigations at the fast neutron therapy facility at Fermilab

    International Nuclear Information System (INIS)

    Langen, K.M.

    1997-01-01

    Microdosimetry was used to investigate three issues at the neutron therapy facility (NTF) at Fermilab. Firstly, the conversion factor from absorbed dose in A-150 tissue equivalent plastic to absorbed dose in ICRU tissue was determined. For this, the effective neutron kerma factor ratios, i.e., oxygen tissue equivalent plastic and carbon to A-150 tissue equivalent plastic, were measured in the neutron beam. An A-150 tissue equivalent plastic to ICRU tissue absorbed dose conversion factor of 0.92 ± 0.04 was determined. Secondly, variations in the radiobiological effectiveness (RBE) in the beam were mapped by determining variations in two related quantities, e * and R, with field size and depth in tissue. Maximal variation in e * and R of 9% and 15% respectively were determined. Lastly, the feasibility of utilizing the boron neutron capture reaction on boron-10 to selectively enhance the tumor dose in the NTF beam was investigated

  8. Fast Neutron Dosimeter for the Space Environment, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Model calculations and risk assessment estimates indicate that secondary neutrons, with energies ranging between 0.5 to >150 MeV, make a significant contribution...

  9. Fast Neutron Dosimeter for the Space Environment, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Secondary neutrons make a significant contribution to the total absorbed dose received by space crews during long duration space missions However, only a limited...

  10. Energy spectra of fast neutrons by nuclear emulsion method

    International Nuclear Information System (INIS)

    Quaresma, A.A.

    1977-01-01

    An experimental method which uses nuclear emulsion plates to determine the energy spectrum of fission neutrons is described. By using this technique, we have obtained the energy distribution of neutrons from spontaneous fission of Cf 2 5 2 . The results are in good agreement with whose obtained previously by others authors who have used different detection techniques, and they are consistent with a Maxwellian distribution as expected by Weisskopf's nuclear evaporation theory. (author)

  11. Attenuation of fast neutron in concretes for biological shielding

    International Nuclear Information System (INIS)

    Labrada, A.; Chavez, A.; Gonzalez Mateu, D.; Desdin, F.; Tenjeiro, J.I.; Tellez, E.

    1993-01-01

    The attenuation of neutrons emitted by an 10 6 n/s. Am-Be source, in concretes elaborated with different aggregates is discussed in this paper. Two measurement methods were used an dosimetric system with Bonner spheres and 6 LiI(Eu) detector, and LAVSAN dielectric nuclear track detectors - with 238 U converts. The concretes elaborated with magnetite is reported as the best for neutron shielding while the Bauxite is not advisable for this purpose

  12. Fast neutron spectroscopy with tensioned metastable fluid detectors

    Energy Technology Data Exchange (ETDEWEB)

    Grimes, T.F.; Taleyarkhan, R.P., E-mail: rusi@purdue.edu

    2016-09-11

    This paper describes research into development of a rapid-turnaround, neutron-spectroscopy capable (gamma-beta blind), high intrinsic efficiency sensor system utilizing the tensioned metastable fluid detector (TMFD) architecture. The inability of prevailing theoretical models (developed successfully for the classical bubble chamber) to adequately predict detection thresholds for tensioned metastable fluid conditions is described. Techniques are presented to overcome these inherent shortcomings, leading thereafter, to allow successful neutron spectroscopy using TMFDs – via the newly developed Single Atom Spectroscopy (SAS) approach. SAS also allows for a unique means for rapidly determining neutron energy thresholds with TMFDs. This is accomplished by simplifying the problem of determining Cavitation Detection Events (CDEs) arising from neutron interactions with one in which several recoiling atom species contribute to CDEs, to one in which only one dominant recoil atom need be considered. The chosen fluid is Heptane (C{sub 7}H{sub 16}) for which only recoiling C atoms contribute to CDEs. Using the SAS approach, the threshold curve for Heptane was derived using isotope neutron source data, and then validated against experiments with mono-energetic (2.45/14 MeV) neutrons from D-D and D-T accelerators. Thereafter the threshold curves were used to produce the response matrix for various geometries. The response matrices were in turn combined with experimental data to recover the continuous spectra of fission (Cf-252) and (α,n) Pu–Be isotopic neutron sources via an unfolding algorithm. A generalized algorithm is also presented for performing neutron spectroscopy using any other TMFD fluid that meets the SAS approach assumptions.

  13. Fast neutron spectroscopy with tensioned metastable fluid detectors

    Science.gov (United States)

    Grimes, T. F.; Taleyarkhan, R. P.

    2016-09-01

    This paper describes research into development of a rapid-turnaround, neutron-spectroscopy capable (gamma-beta blind), high intrinsic efficiency sensor system utilizing the tensioned metastable fluid detector (TMFD) architecture. The inability of prevailing theoretical models (developed successfully for the classical bubble chamber) to adequately predict detection thresholds for tensioned metastable fluid conditions is described. Techniques are presented to overcome these inherent shortcomings, leading thereafter, to allow successful neutron spectroscopy using TMFDs - via the newly developed Single Atom Spectroscopy (SAS) approach. SAS also allows for a unique means for rapidly determining neutron energy thresholds with TMFDs. This is accomplished by simplifying the problem of determining Cavitation Detection Events (CDEs) arising from neutron interactions with one in which several recoiling atom species contribute to CDEs, to one in which only one dominant recoil atom need be considered. The chosen fluid is Heptane (C7H16) for which only recoiling C atoms contribute to CDEs. Using the SAS approach, the threshold curve for Heptane was derived using isotope neutron source data, and then validated against experiments with mono-energetic (2.45/14 MeV) neutrons from D-D and D-T accelerators. Thereafter the threshold curves were used to produce the response matrix for various geometries. The response matrices were in turn combined with experimental data to recover the continuous spectra of fission (Cf-252) and (α,n) Pu-Be isotopic neutron sources via an unfolding algorithm. A generalized algorithm is also presented for performing neutron spectroscopy using any other TMFD fluid that meets the SAS approach assumptions.

  14. Method and apparatus for dual-spaced fast/epithermal neutron porosity measurements

    International Nuclear Information System (INIS)

    Smith, H.D. Jr.

    1986-01-01

    A method is described for determining the porosity of earth formations in the vicinity of a well borehole, comprising: (a) irradiating the earth formations in the vicinity of the well borehole with a continuous chemical type source of fast neutrons, (b) detecting the fast neutron population at a first shorter spaced distance from the neutron source in the borehole and generating signals representative thereof, (c) detecting the epithermal neutron population at a second space distance from the neutron source in the borehole and generating signals representative thereof, the second spaced distance being greater than the first spaced distance from the neutron source, (d) forming a ratio of the signals representing the fast and epithermal neutron populations to derive a measurement signal functionally related to the porosity of the earth formations in the vicinity of the borehole, and (e) calibrating the measurement signal according to a predetermined functional relationship to derive a porosity signal quantitatively representative of the porosity of the earth formations in the vicinity of the borehole

  15. Measurements of the energy spectrum of backscattered fast neutrons

    International Nuclear Information System (INIS)

    Segal, Y.

    1976-03-01

    Experimental measurements have been made of the energy spectra of neutrons transmitted through slabs of iron, lead and perspex for incident neutron energies of 0.5, 1.0, 1.5 and 1.8 MeV. The neutron energy measurements were made using a He-3 spectrometer. The dependence of the neutrons energy spectrum as a function of scattering thickness was determined. The neutrons source used was a 3MeV Van de Graaff accelerator with a tritium target using the H 3 (p,n) He 3 reaction. The results obtained by the investigator on energy dependence of transmitted neutrons as a function of thickness of scattering material were compared, where possible, with the results obtained by other workers. The comparisons indicated good agreement. The experiment's results are compared with MORSE Monte Carlo calculated values. It is worthwhile to note that direct comparison between measured cross section values and the recommended ones are very far from satisfactory. In almost all cases the calculated spectrum is harder than the experimental one, a situation common to the penetrating and the back-scattered flux

  16. DETERMINATION OF LIMIT DETECTION OF THE ELEMENTS N, P, K, Si, Al, Fe, Cu, Cd, WITH FAST NEUTRON ACTIVATION USING NEUTRON GENERATOR

    OpenAIRE

    Sunardi, Sunardi; Muryono, Muryono

    2010-01-01

    Determination of limit detection of the elements N, P, K, Si, Al, Fe, Cu, Cd, with fast neutron activation using neutron generator has been done.  Samples prepared from SRM 2704, N, P, K elements from MERCK, Cu, Cd, Al from activation foil made in San Carlos, weighted and packed for certain weight then iradiated during 30 minutes with 14 MeV fast neutron using the neutron generator and then counted with gamma spectrometry (accuspec).  At this research condition of neutron generator was set at...

  17. Study of the production of neutron-rich isotope beams issuing from fissions induced by fast neutrons

    International Nuclear Information System (INIS)

    Lau, Ch.

    2000-01-01

    This work is a contribution to the PARRNe project (production of radioactive neutron-rich isotopes). This project is based on the fission fragments coming from the fission of 238-uranium induced by fast neutrons. The fast neutron flux is produced by the collisions of deutons in a converter. Thick targets of uranium carbide and liquid uranium targets have been designed in order to allow a quick release of fission fragments. A device, able to trap on a cryogenic thimble rare gas released by the target, has allowed the production of radioactive nuclei whose half-life is about 1 second. This installation has been settled to different deuton accelerators in the framework of the European collaboration SPIRAL-2. A calibration experiment has proved the feasibility of fixing an ISOL-type isotope separator to a 15 MV tandem accelerator, this installation can provide 500 nA deutons beams whose energy is 26 MeV and be a valuable tool for studying fast-neutron induced fission. Zinc, krypton, rubidium, cadmium, iodine, xenon and cesium beams have been produced in this installation. The most intense beams reach 10000 nuclei by micro-coulomb for 26 MeV deutons. An extra gain of 2 magnitude orders can be obtained by using a more specific ion source and by increasing the thickness of the target. Another extra gain of 2 magnitude orders involves 100 MeV deutons

  18. Scanning of Cargo Containers by Gamma-Ray and Fast Neutron Radiography

    International Nuclear Information System (INIS)

    Yousri, A.M.; Bashter, I.I.; Megahid, M.R.; Osman, A.M.; Kansouh, W.A.; Reda, A.M.

    2011-01-01

    This paper describes the combined systems which were installed and tested to detect contraband smuggled in cargo containers. These combined systems are based on radiographers work by gamma-rays emitted from point source 60 Co with 0.5 Ci activity and neutrons emitted from point isotopic sources of Pu-α-Be as well as 14 MeV neutrons emitted from sealed tube neutron generator. The transmitted gamma ray through the inspected object was measured by gamma detection system with NaI(Tl) detector while the transmitted fast neutron beam was measured by a neutron gamma detection system with stilbene organic scintillator. The later possess the capability of discrimination between between gamma and neutron pulses using a discrimination system based on pulse shape discrimination method. The measured intensities of primary incident and transmitted beams of gamma-rays and fast neutrons were used to construct 2D cross-sectional images of the inspected objects hidden directly within benign materials of the container and for object screened by high dense material to stop object detection by gamma or X-rays. The constructed images for the inspected objects show the good capability and effectiveness of the installed gamma and neutron radiographers to detect illicit materials hidden in air cargo containers and sea containers of med size. They have also indicated that the developed scanning systems possess the ease of mobility and low cost of scanning

  19. Development of a novel direction-position sensing fast neutron detector using tensioned metastable fluids

    Science.gov (United States)

    Archambault, Brian C.; Webster, Jeffrey A.; Lapinskas, Joseph R.; Grimes, Thomas F.; Taleyarkhan, Rusi

    2012-05-01

    A directional-position sensing fast neutron sensor utilizing the acoustic tensioned metastable fluid detector (ATMFD) is described. This ATMFD system enables the determination of directionality of incoming neutron radiation with a single detector, and is developed based on a combination of experimentation and theoretical assessments. Benchmarking and qualifications studies conducted with a 1 Ci Pu-Be neutron source produced encouraging results. These results indicated that the ATMFD is not only comparable in technical performance with competing directional fast neutron detector-bank technologies under development worldwide, but it promised to do so with a single detector and at a significant reduction in both cost and size while remaining completely blind to nonneutron background radiation. Applications to neutron source spatial imaging and standoff detection with the ATMFD system are also presented. The ATMFD was found to successfully locate a hidden neutron source in a blind test. Assessments for practically relevant situations were conducted and it was revealed that an ATMFD system (with a 6 cm×10 cm cross-sectional area) could offer directionality on incoming neutron radiation from a 8 kg Pu source at 25 m standoff, with a resolution of 11.2°, with 68% confidence within 60 s. Position and neutron source image sensing capability were also demonstrated using two ATMFDs.

  20. Utilization of boron irradiation filters in reactor neutron activation via epithermal (n,γ) and fast neutron reactions

    International Nuclear Information System (INIS)

    Chisela, F.

    1986-01-01

    The technique of instrumental neutron activation analysis based on irradiation with reactor epithermal and fast neutrons has been described and evaluated. Important characteristics of boron neutron absorbers used to remove thermal neutrons from the reactor neutron spectrum have been examined and compared with those of cadmium. Three boron compound shields, have been designed and constructed at the BER II 5MW reactor for use in epithermal neutron activation analysis of biological materials. The major advantages offered by these filters in this application include the flexibility of varying the filter thickness, the low radioactivity induced in the filters during irradiation, ease of fabrication and the relatively low cost of the filter materials. The radiation heating due to the 10 B(n,α) 7 Li-reaction has been experimentally investigated for the filters used and the results obtained confirm the necessity for efficient cooling of these filters during irradiation. Three irradiation facilities have been characterized with respect to the neutron flux density and the flux spatial distribution. An experiment has been designed and carried out to compensate the flux inhomogeneity in two irradiation positions of the DBV facility caused by the reactor geometry. Several biological samples including well characterized reference materials have been analysed after epithermal activation and the results compared with those obtained with the classical thermal neutron activation method. Improved sensitivity of determination has been found for elements with high resonance integral to thermal neutron cross section ratios (RI/σ 0 ). The range of elements that can be determined instrumentally is extended and the time scale of analysis is considerably reduced. (orig.) [de

  1. Nitrogen determination in wheat by neutron activation analysis using fast neutron flux from a thermal nuclear reactor

    International Nuclear Information System (INIS)

    Ramirez G, T.

    1976-01-01

    This is a study of the technique for the determination of nitrogen and other elements in wheat flour through activation analysis with fast neutrons from a thermal nuclear reactor. The study begins with an introduction about the basis of the analytical methods, the equipment used in activation analysis and a brief description of the neutrons source. In the study are included the experiments carried out in order to determine the flux form in the site of irradiation, the N-13 half life and the interference due to the sample composition. (author)

  2. Fast-neutron scattering from vibrational palladium nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.B. [Argonne National Lab., IL (United States)]|[Univ. of Arizona, Tucson, AZ (United States); Guenther, P.T. [Argonne National Lab., IL (United States)

    1993-10-01

    Neutron total cross sections of elemental palladium are measured from {approx}0.6--4.5 MeV. These results, combined with others previously reported from this laboratory, provide a detailed knowledge of the neutron total cross sections of palladium from {approx}0.1--20 MeV. Differential neutron elastic-scattering cross sections are measured from {approx}1.5--10 MeV in sufficient energy and angle detail to well define the energy-average behavior. Concurrently, neutron inelastic-scattering cross sections are measured from {approx}1.5--8 MeV. Inelastically-scattered neutron groups are observed corresponding to excitations of: 306 {+-} 14, 411 {+-} 47, {approx}494, 791 {+-} 20, 924 {+-} 20, 1,156 {+-} 24, 1,358 {+-} 35, 1,554 {+-} 47 and 1,706 {+-} 59 keV, with additional tentative groups at 1,938 and 2,059 keV. Particular attention is given to the inelastic excitation of the 2{sup +} yrast states of the even isotopes. This broad data base is examined in the context of optical-statistical and coupled-channels models. The resulting model parameters are consistent with systematic trends in this vibrational mass region previously noted at this laboratory, and provide a suitable vehicle for many applications.

  3. Development of fast neutron therapy worldwide. Radiobiological, clinical and technical aspects

    International Nuclear Information System (INIS)

    Wambersie, A.; Richard, F.; Breteau, N.

    1994-01-01

    Radiobiological data indicate that fast neutrons could bring a benefit in the treatment of some tumour types, and suggest mechanisms through which this benefit could be achieved. However, radiobiology also clearly indicates that there is a need for patient selection as well as for a high-physical selectivity. The main difficulty when interpreting the results of neutron therapy are the poor technical conditions in which the first treatments were applied. This explains why the value and the place of neutron therapy are not universally recognized, although more than 15000 patients have been treated so far worldwide. There are, however, clinical indications of fast neutrons bringing a benefit for the following tumour sites: salivary glands, paranasal sinuses, soft tissue sarcomas, prostatic adenocarcinomas, palliative treatment of melanoma and rectum. These tumours represent about 10-15% of all patients currently referred to the radiation therapy departments. (orig.)

  4. The radiation damage in silicon diodes induced by stray fast neutrons from the ANSTO Cyclotron

    International Nuclear Information System (INIS)

    Mukherjee, B.

    1996-01-01

    Intense flux of fast neutrons are produced during routine isotope production runs at the National Medical Cyclotron. These stray neutrons induce irreversible displacement damage in the semiconductor devices, the vital building blocks of the various electronic instruments used in the facility. This poster highlights the results of the radiation hardness investigation study of commercial silicon diodes undertaken at the Health Physics laboratory of the National Medical Cyclotron

  5. Measured Thermal and Fast Neutron Fluence Rates for ATF-1 Holders During ATR Cycle 157D

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Larry Don [Idaho National Lab. (INL), Idaho Falls, ID (United States); Miller, David Torbet [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-03-01

    This report contains the thermal (2200 m/s) and fast (E>1MeV) neutron fluence rate data for the ATF-1 holders located in core for ATR Cycle 157D which were measured by the Radiation Measurements Laboratory (RML) as requested by the Power Reactor Programs (ATR Experiments) Radiation Measurements Work Order. This report contains measurements of the fluence rates corresponding to the particular elevations relative to the 80-ft. core elevation. The data in this report consist of (1) a table of the ATR power history and distribution, (2) a hard copy listing of all thermal and fast neutron fluence rates, and (3) plots of both the thermal and fast neutron fluence rates. The fluence rates reported are for the average power levels given in the table of power history and distribution.

  6. A study on the development of a fast neutron television converter

    International Nuclear Information System (INIS)

    Yoshii, Koji; Miya, Kenzo

    1993-01-01

    Experiments on fast neutron radiography (FNR) were carried out using the fast neutron source reactor YAYOI of the University of Tokyo. For a real time imaging technique using FNR, for a fast neutron television system (FNR-TV), it is essential to develop a highly sensitive luminescent converter in order to obtain good quality images. A new converter was recently developed and tested. It showed an about six times higher sensitivity compared with the first prototype converter. In this paper, the characteristics of the converter are discussed as well as the clearer images of a FNR-TV when using the converter. The FNR-TV images were obtained with 500 frames integrated. A small hole (1.0 mm in diameter and 10 mm in depth) in an acrylic plate was well imaged through a 50 mm thick iron block. A 0.15 mm thick aluminum spacer in the calibrated fuel pin was also discernible. (orig.)

  7. On angular distribution of nucleus fission fragments by fast neutrons

    International Nuclear Information System (INIS)

    Barabanov, A.L.; Grechukhin, D.P.

    1987-01-01

    Evaluation of amplitudes of quadrupole and hexadecapole components of angular distribution of nucleus fission fragments by neutrons with the energies E n < or approx. 6 MeV is conducted. Stability of this amplitude to permeability optical coefficient variations for neutrons is revealed. It is shown, that the ratio of these amplitudes as well as the character of their dependence on the target nucleus orientation degree are sensitive to the type of fission probability distribution along K projection if fissile nucleus J spin to the fragment scattering axis. This sensitivity may be used for fragment angular distribution anisotropy formation statistical model verification

  8. Investigations on fast neutron interactions with constructional materials

    International Nuclear Information System (INIS)

    Vasvary, L.; Divos, F.; Petoe, G.; Csikai, J.; Mumba, N.K.

    1985-01-01

    On the basis of flight-time difference the direct and scattered neutrons, as well as gammas produced in the target head, and samples were separated. Using this method the attenuation of primary neutrons and gammas originating from the target head was studied in addition to the measurements on the thickness dependence of the secondary gamma yield from extended samples of Al, Fe, Pb, paraffin and reinforced concrete. Results indicate a geometry dependence of the removal cross sections. The removal cross section of brick, gravel, sand, river sand, reinforced concrete and water was also measured by activation threshold detector technique. (author)

  9. Fast neutron flux analyzer with real-time digital pulse shape discrimination

    Energy Technology Data Exchange (ETDEWEB)

    Ivanova, A.A., E-mail: a.a.ivanova@inp.nsk.su [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Zubarev, P.V. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Novosibirsk State Technical University, 630092 Novosibirsk (Russian Federation); Ivanenko, S.V. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Khilchenko, A.D. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Novosibirsk State Technical University, 630092 Novosibirsk (Russian Federation); Kotelnikov, A.I. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Polosatkin, S.V. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Novosibirsk State Technical University, 630092 Novosibirsk (Russian Federation); Novosibirsk State University, 630090 Novosibirsk (Russian Federation); Puryga, E.A.; Shvyrev, V.G. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Novosibirsk State Technical University, 630092 Novosibirsk (Russian Federation); Sulyaev, Yu.S. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 630090 Novosibirsk (Russian Federation)

    2016-08-11

    Investigation of subthermonuclear plasma confinement and heating in magnetic fusion devices such as GOL–3 and GDT at the Budker Institute (Novosibirsk, Russia) requires sophisticated equipment for neutron-, gamma- diagnostics and upgrading data acquisition systems with online data processing. Measurement of fast neutron flux with stilbene scintillation detectors raised the problem of discrimination of the neutrons (n) from background cosmic particles (muons) and neutron-induced gamma rays (γ). This paper describes a fast neutron flux analyzer with real-time digital pulse-shape discrimination (DPSD) algorithm FPGA-implemented for the GOL–3 and GDT devices. This analyzer was tested and calibrated with the help of {sup 137}Cs and {sup 252}Cf radiation sources. The Figures of Merit (FOM) calculated for different energy cuts are presented. - Highlights: • Electronic equipment for measurement of fast neutron flux with stilbene scintillator is presented. • FPGA-implemented digital pulse-shape discrimination algorithm by charge comparison method is shown. • Calibration of analyzer was carried out with {sup 137}Cs and {sup 252}Cf. • Figures of Merit (FOM) values for energy cuts from 1/8 Cs to 2 Cs are from 1.264 to 2.34 respectively.

  10. Present state and prospects of fast neutrons application in cancer therapy in Krakow

    International Nuclear Information System (INIS)

    Skolyszewski, J.; Huczkowski, J.

    1986-01-01

    The results of the therapy in the group of 89 patients with advanced head and neck cancer treated with fast neutrons (5.6MeV mean neutron energy) are presented. Fifteen patients (16.9%) survived two years and fourteen from them (15.7%) without any symptons of cancer. The pilot results of radiobiological experiments performed on clinical neutron beam are also included. These are: RBE determination with the use of Withers-Elkind microcolony assay (acute radiation effects on the survival of crypt cells in the mouse intestine) and the RBE determination for late large bowel stenosis in Wistar rats after local irradiation (Trott-Kiszel assay). Both assays will be used to study the RBE neutron beams from new isochronic cyclotron (accelerating deuterons up to 25 MeV and protons up to 50 MeV). Such cyclotron was built in Cracow and will be used also in neutron cancer therapy. 26 refs., 7 figs. (author)

  11. Capabilities, Calibration, and Impact of the ISS-RAD Fast Neutron Detector

    Science.gov (United States)

    Leitgab, Martin

    2015-01-01

    In the current NASA crew radiation health risk assessment framework, estimates for the neutron contributions to crew radiation exposure largely rely on simulated data with sizeable uncertainties due to the lack of experimental measurements inside the ISS. Integrated in the ISS-RAD instrument, the ISS-RAD Fast Neutron Detector (FND) will deploy to the ISS on one of the next cargo supply missions. Together with the ISS-RAD Charged Particle Detector, the FND will perform, for the first time, routine and precise direct neutron measurements inside the ISS between 0.5 and 80 MeV. The measurements will close the NASA Medical Operations Requirement to monitor neutrons inside the ISS and impact crew radiation health risk assessments by reducing uncertainties on the neutron contribution to crew exposure, enabling more efficient mission planning. The presentation will focus on the FND detection mechanism, calibration results and expectations about the FND's interaction with the mixed radiation field inside the ISS.

  12. A New Neutron Calibration Technique with Fast Scintillators on DIII-D Tokamak

    Science.gov (United States)

    Zhu, Y. B.; Heidbrink, W. W.; Taylor, P. L.; Carrig, W.

    2015-11-01

    Absolute calibrations are necessary for conventional neutron measurements based on proportional counters and fission chambers, at regular intervals. For the DIII-D tokamak, the wide span of fusion rates, approximately between 1.e9 - 1.e17 neutrons per second, from pure Ohmic to high power auxiliary heating plasmas requires careful cross-calibrations of a variety of neutron detectors with stepwise and overlapped sensitivities, with an intense isotope neutron source, e.g. californium-252 and real plasmas. Scintillators have been successfully utilized for fast time resolved neutron detection for decades. A new calibration approach with the help of scintillators is shown to be straightforward, simpler and trustworthy while the conventional approach is complicated, time consuming and costly. Details on the calibration setup and results will be presented. Supported by US DOE SC-G903402 and DE-FC02-04ER54698.

  13. Chromosome aberrations in human lymphocytes after irradiation with NIRS-cyclotron fast neutrons in vitro

    International Nuclear Information System (INIS)

    Muramatsu, Susumu; Maruyama, Takashi

    1977-01-01

    The dose-response relationships for inducing chromosome aberrations (dicentrics) in human lymphocytes were studied by whole-blood microculture following in vitro exposures at various doses either 200 kVp x-rays or NIRS-cyclotron fast neutrons. The yields of dicentrics induced were dependent on the exposure dose of two types of radiations between 48 to 384 rad and 25 to 400 rad by x-rays and fast neutrons, respectively. The dicentrics yields gave the best fit to the linear quadratic function Y=αD + βD 2 ; namely Y sub(X)=3.66 x 10 -4 D + 8.01 x 10 -6 D 2 for x-rays and Y sub(N)=28.90 x 10 -4 D + 4.04 x 10 -6 D 2 for fast neutrons. The RBE value of NIRS-cyclotron fast neutrons versus 200 kVP x-rays decreased with increasing neutron doses, for example from 2.3 at 50 rad to 1.2 at doses up to 300 rad. (auth.)

  14. Comparison of different PADC materials and etching conditions for fast neutron dosimetry

    International Nuclear Information System (INIS)

    Assenmacher, F.; Boschung, M.; Hohmann, E.; Mayer, S.

    2016-01-01

    Etched-track polyallyl diglycol carbonate (PADC) dosemeters have been in use at the Paul Scherrer Institute since 1998 in neutron dosimetry for individual monitoring. In the last years, the availability of PADC materials from different manufacturers has grown, and different etching conditions were proposed, with the intention to improve the quality and overall performance of PADC in individual neutron monitoring. The goal of the present study was to compare the performance of different PADC materials and to investigate the influence of different etching conditions on sensitivity to fast neutrons and lower detection limit. The comparison covers six different PADC materials and eight different etching conditions. (authors)

  15. Neutron transport calculations of some fast critical assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Val Penalosa, J. A.

    1976-07-01

    To analyse the influence of the input variables of the transport codes upon the neutronic results (eigenvalues, generation times, . . . ) four Benchmark calculations have been performed. Sensitivity analysis have been applied to express these dependences in a useful way, and also to get an unavoidable experience to carry out calculations achieving the required accuracy and doing them in practical computing times. (Author) 29 refs.

  16. Micronuclei induced by fast neutrons versus 60Co gamma-rays in human peripheral blood lymphocytes.

    Science.gov (United States)

    Vral, A; Verhaegen, F; Thierens, H; De Ridder, L

    1994-03-01

    Here we compared the effectiveness of neutrons ( = 5.5 MeV) versus 60Co gamma-rays in producing micronuclei (MN) in human lymphocytes. To obtain dose-response data, blood samples of six donors were irradiated with doses ranging from 0.1 to 5 Gy for gamma-rays and 0.1-3 Gy for neutrons. A linear dependence of MN yield with dose was found for fast neutrons while for gamma-rays a nonlinear dependence existed. For both radiation qualities no significant interindividual differences were found. Derived relative biological effectiveness values decreased with increasing dose. The MN frequency distributions were overdispersed with respect to the Poisson distribution, with neutrons showing higher dispersion values than with gamma-rays. To compare the repair kinetics of both radiation qualities split-dose experiments were performed. A dose of 4 Gy gamma-rays (3 Gy neutrons) was delivered either as a single exposure or in two equal fractions separated by time intervals ranging from 30 min to 10 h (30 min to 7 h for neutrons). The data showed for gamma-rays a significant decline (30% +/- 10%) in MN yield with interfraction time due to repair of DNA damage. This repair is a continuous process starting almost immediately after the first of the two doses and lasting 3-5 h. For fast neutrons no decline was observed indicating irreparable damage.

  17. Determination of the fast neutrons spectra by the Elastic scattering method (n, p)

    International Nuclear Information System (INIS)

    Elizalde D, J.

    1973-01-01

    This work consists in determining the fast neutron spectra emitted by a Pu-Be isotopic source. The implemented technique is based in the spectrometry (n, p). This consists in making to fall on a fast neutrons beams (polyenergetic) over a thin film of hydrogenated material, detecting the spectra of emitted protons at a fix angle. The polyethylene film and the used solid state detector are inside of a vacuum chamber. The detector is placed at 30 degree with respect to direction of the incident neutrons beam. The protons spectra is stored in a multichannel. the energy is obtained with the prior calibration of the system. The data processing involves the transformation of the protons spectra observed at the falling on neutrons spectra over the film. The energy of the neutrons is related with that of the protons, according to the collision kinematical equations. The cross section of elastic collision of the neutrons with the hydrogen atoms is obtained from literature. Applying these relations to the observed spectra it is obtained the falling on neutron spectra over the film. (Author)

  18. Development and characterization of a D-D fast neutron generator for imaging applications.

    Science.gov (United States)

    Adams, Robert; Bort, Lorenz; Zboray, Robert; Prasser, Horst-Michael

    2015-02-01

    The experimental characterization of a pulsed D-D fast neutron generator designed for fan-beam tomography applications is presented. Using Monte Carlo simulations the response of an LB6411 neutron probe was related to the neutron generator output. The yield was measured to be up to ∼10(7) neutrons/s. An aluminum block was moved stepwise between the source and a BC400 plastic scintillator detector in order to measure an edge response. This edge response was related to the neutron emitting spot size using Monte Carlo simulations and a simplified geometry-based model. The experimentally determined spot size of 2.2 mm agreed well with the simulated value of 1.5 mm. The time-dependence of pulsed output for various operating conditions was also measured. The neutron generator was found to satisfy design requirements for a planned fast neutron tomography arrangement based on a plastic scintillator detector array which is expected to be capable of producing 2D tomograms with a resolution of ∼1.5 mm. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Changes of Dielectric Properties induced by Fast neutrons in Tissue Equivalent Plastic A-150

    International Nuclear Information System (INIS)

    Abdou, M.S.

    2000-01-01

    Tissue equivalent plastic A-150 (TEP A-150) samples are exposed to fast neutrons. Dielectric studies for TEP A-150 are carried out in the frequency range from 40 Hz to 4 MHz in the temperature range 295-343 K. The obtained data revealed that, both the dielectric properties and conductivity sigma ac (omega) of TEP A-150 are altered when irradiated by a relatively high fast neutron dose (15 Sv). The values of dielectric constant and conductivity are increased for the irradiated samples to about 24% than the blank samples

  20. Recent Fast Neutron Imaging Measurements with the Fieldable Nuclear Materials Identification System

    Energy Technology Data Exchange (ETDEWEB)

    Mullens, James Allen [ORNL; Mihalczo, John T [ORNL; Archer, Daniel E [ORNL; Thompson, Thad [ORNL; Britton Jr, Charles L [ORNL; Ezell, N Dianne Bull [ORNL; Ericson, Milton Nance [ORNL; Farquhar, Ethan [ORNL; Lind, Randall F [ORNL; Carter, Jake [ORNL

    2015-01-01

    This paper describes some recent fast neutron imaging measurements of the fieldable nuclear materials identification system (FNMIS) under development by the National Nuclear Security Administration (NNSA-NA-22) for possible future use in arms control and nonproliferation applications. The general configuration of FNMIS has been previously described, and a description of the application-specific integrated circuit (ASIC) electronics designed for FNMIS has been reported. This paper presents initial imaging measurements performed at ORNL with a Thermo Fisher API 120 DT generator and the fast-neutron imaging module of FNMIS.

  1. Cr-39 fast neutron dosemeter based on A (n, α) converter

    International Nuclear Information System (INIS)

    Widayati, S.; Budiantari, T.

    1998-01-01

    The aim of this experiment is to obtained the response of Cr-39 as fast neutron dosemeter based on an (n, α) converter. Cr-39 was irradiated to AmBe fast neutron flux from 0.10 mSv to 2.5 mSv. Cr-39 processed by chemical etching with NaOH 20 % at temperature of 60 oC in six hours. The results of experiment showed that the response of Cr-39 based on an (n, α) converter is 6 times bigger than the response of Cr-39 without (n, α) converter. (author)

  2. Fast neutron dosimetry. Progress report, 30 August 1992--1 September 1993

    Energy Technology Data Exchange (ETDEWEB)

    DeLuca, P.M. Jr.; Pearson, D.W.

    1993-12-01

    Research concentrated on three major areas during the last twelve months: (1) investigations of energy fluence and absorbed dose measurements using crystalline and hot pressed TLD materials exposes to ultrasoft beams of photons, (2) fast neutron kerma factor measurements for several important elements as well as NE-213 scintillation material response function determinations at the intense ``white`` source available at the WNR facility at LAMPF, and (3) kerma factor ratio determinations for carbon and oxygen to A-150 tissue equivalent plastic at the clinical fast neutron radiation facility at Harper Hospital, Detroit, MI. Progress summary reports of these efforts are given in this report.

  3. Small-angle neutron and X-ray scattering studies of supraatomic structure of synthetic quartz irradiated by fast neutrons

    International Nuclear Information System (INIS)

    Lebedev, V.M.; Lebedev, V.T.; Orlov, S.P.; Golubkov, V.V.; Pevzner, B.Z.; Tolstikhin, I.N.

    2008-01-01

    Quartz nanostructures have been simulated for the investigation into diffusion of gases in the Earth crust. The nanostructure of synthetic quartz irradiated by fast neutrons with energy E n >0.1 MeV was studied by neutron and X-ray small-angle scattering. The range of neutron fluence is of 10 17 cm -2 up to 2x10 -2 0 cm -2 . In the irradiated samples the different kinds of defects such as point-like, extended linear (dislocations) and globular (size ∼100 nm, amorphous phase nuclei) were observed. The density of highly irradiated quartz (fluence 2x10 20 cm -2 ) is shown to decrease by 0.39 g/cm 2 and reach the magnitude of 2.260 g/cm 2 corresponding to 100% metamict phase. The first results of model structures helium saturation have been received [ru

  4. Fast neutron spectra determination by threshold activation detectors using neural networks

    International Nuclear Information System (INIS)

    Kardan, M.R.; Koohi-Fayegh, R.; Setayeshi, S.; Ghiassi-Nejad, M.

    2004-01-01

    Neural network method was used for fast neutron spectra unfolding in spectrometry by threshold activation detectors. The input layer of the neural networks consisted of 11 neurons for the specific activities of neutron-induced nuclear reaction products, while the output layers were fast neutron spectra which had been subdivided into 6, 8, 10, 12, 15 and 20 energy bins. Neural network training was performed by 437 fast neutron spectra and corresponding threshold activation detector readings. The trained neural network have been applied for unfolding 50 spectra, which were not in training sets and the results were compared with real spectra and unfolded spectra by SANDII. The best results belong to 10 energy bin spectra. The neural network was also trained by detector readings with 5% uncertainty and the response of the trained neural network to detector readings with 5%, 10%, 15%, 20%, 25% and 50% uncertainty was compared with real spectra. Neural network algorithm, in comparison with other unfolding methods, is very fast and needless to detector response matrix and any prior information about spectra and also the outputs have low sensitivity to uncertainty in the activity measurements. The results show that the neural network algorithm is useful when a fast response is required with reasonable accuracy

  5. Online monitoring of fast neutron (DT/DD) at Purnima neutron generator

    International Nuclear Information System (INIS)

    Bishnoi, S.; Patel, T.; Shukla, M.; Adhikari, P.S.; Sinha, A.

    2012-01-01

    A neutron generator (NG) at Purnima Labs, BARC has been developed for DT accelerator driven zero power subcritical (ADSS) system. Subcritical core of ADSS will be coupled to the NG for benchmarking experiments. Kinetic parameters of ADSS such as K-source, flux, power etc depends on this external neutron source strength injected to the core. However the neutron emission rate of NG does not remain stable throughout its operation. In view of this a reliable, precise and online monitoring of NG's neutron emission rate is required. An online neutron monitoring system based on associated particle method has been designed, developed and installed at NG. The monitoring unit consists of an ion implanted planar silicon detector, placed inside the drift tube of NG at an angle with respect to D + beam direction. A series of experiments were carried out with increasing neutron yield to optimize the position of detector such that it has sufficient counting statistics and minimum pileup. A complementary calibration procedure for validating these results based on activation technique was also carried out with standard Cu foil. The reaction rate monitored with online monitor and foil activation technique were compared, their variations with the predicted (theoretical) results were within 16%. This paper deals with the development and performance of online neutron monitoring system for DT and DD neutrons

  6. Determining of the intermediate neutron spectrum in fast neutron field at the RB reactor

    International Nuclear Information System (INIS)

    Sokcic-Kostic, M.; Pesic, M.; Antic, D.

    1987-01-01

    The activation method for intermediate neutron spectrum determination is given in this paper. The intermediate neutron spectrum in experimental fuel channel (EFC) at the RB reactor is determined om the basis of this method. The results of measurements are treated with PRAG code and will be treated with KRIFIT and TENET codes that are also developed. (author)

  7. The sensitivity calibration of the ultra-fast quench plastic scintillation detector for D-T neutrons

    International Nuclear Information System (INIS)

    Tang Changhuan; Yan Meiqiong; Xie Chaomei

    1998-01-01

    The authors introduce some characteristics of ultra-fast quench plastic scintillation detectors. When the detectors are composed of different scintillators, light guides and microchannel plate photomultiplier tube (MCP-PMT), their sensitivities to D-T neutrons are calibrated by a pulse neutron tube with a neutron pulse width about 10 ns

  8. Fast neutron irradiation for locally advanced pancreatic cancer

    Energy Technology Data Exchange (ETDEWEB)

    Smith, F.P. (Georgetown Univ. Medical Center, Washington, DC); Schein, P.S.; MacDonald, J.S.; Woolley, P.V.; Ornitz, R.; Rogers, C.

    1981-11-01

    Nineteen patients with locally advanced pancreatic cancer and one patient with islet cell cancer were treated with 1700-1500 neutron rad alone or in combination with 5-fluorouracil to exploit the theoretic advantages of higher linear energy of transfer, and lower oxygen enhancement ratio of neutrons. Only 5 of 14 (36%) obtained partial tumor regression. The median survival for all patients with pancreatic cancer was 6 months, which is less than that reported with 5-fluorouracil and conventional photon irradiation. Gastrointestinal toxicity was considerable; hemorhagic gastritis in five patients, colitis in two and esophagitis in one. One patient developed radiation myelitis. We therefore, caution any enthusiasm for this modality of therapy until clear evidence of a therapeutic advantage over photon therapy is demonstrated in controlled clinical trials.

  9. Fast neutron irradiation for locally advanced pancreatic cancer

    International Nuclear Information System (INIS)

    Smith, F.P.; Schein, P.S.; MacDonald, J.S.; Woolley, P.V.; Ornitz, R.; Rogers, C.

    1981-01-01

    Nineteen patients with locally advanced pancreatic cancer and one patient with islet cell cancer were treated with 1700-1500 neutron rad alone or in combination with 5-fluorouracil to exploit the theoretic advantages of higher linear energy of transfer, and lower oxygen enhancement ratio of neutrons. Only 5 of 14 (36%) obtained partial tumor regression. The median survival for all patients with pancreatic cancer was 6 months, which is less than that reported with 5-fluorouracil and conventional photon irradiation. Gastrointestinal toxicity was considerable; hemorhagic gastritis in five patients, colitis in two and esophagitis in one. One patient developed radiation myelitis. We therefore, caution any enthusiasm for this modality of therapy until clear evidence of a therapeutic advantage over photon therapy is demonstrated in controlled clinical trials

  10. Some time dependent aspects of fast neutron induced atomic cascades

    International Nuclear Information System (INIS)

    Williams, M.M.R.

    1976-01-01

    Analytical results are obtained for the time-energy distribution of neutrons and the associated displaced atoms slowing down in an amorphous medium according to a general force law. Explicit results are given for the inverse power law, and applications to hard-sphere and Coulomb scattering are discussed. Complete results are obtained for the steady state energy distribution of particles arising from a primary knock-on, and from a neutron initiated cascade. The speed of the slowing down process is assessed by calculating the slowing down time of particles. Two different concepts of slowing down time are discussed, one based upon a density average and the other on a slowing down density average. It is shown that the latter definition is physically more realistic and mathematically simpler. (author)

  11. Fast-neutron scattering cross sections of elemental silver

    International Nuclear Information System (INIS)

    Smith, A.B.; Guenther, P.T.

    1982-05-01

    Differential neutron elastic- and inelastic-scattering cross sections of elemental silver are measured from 1.5 to 4.0 MeV at intervals of less than or equal to 200 keV and at 10 to 20 scattering angles distributed between 20 and 160 0 . Inelastically-scattered neutron groups are observed corresponding to the excitation of levels at; 328 +- 13, 419 +- 50, 748 +- 25, 908 +- 26, 1150 +- 38, 1286 +- 25, 1507 +- 20, 1623 +- 30, 1835 +- 20 and 1944 +- 26 keV. The experimental results are used to derive an optical-statistical model that provides a good description of the observed cross sections. The measured values are compared with corresponding quantities given in ENDF/B-V

  12. Fast-neutron total and scattering cross sections of niobium

    International Nuclear Information System (INIS)

    Smith, A.B.; Guenther, P.T.; Whalen, J.F.

    1982-07-01

    Neutron total cross sections of niobium were measured from approx. = 0.7 to 4.5 MeV at intervals of less than or equal to 50 keV with broad resolution. Differential-elastic-scattering cross sections were measured from approx. = 1.5 to 4.0 MeV at intervals of 0.1 to 0.2 MeV and at 10 to 20 scattering angles distributed between approx. = 20 and 160 degrees. Inelastically-scattered neutrons, corresponding to the excitation of levels at: 788 +- 23, 982 +- 17, 1088 +- 27, 1335 +- 35, 1504 +- 30, 1697 +- 19, 1971 +- 22, 2176 +- 28, 2456 +- (.), and 2581 +- (.) keV, were observed. An optical-statistical model, giving a good description of the observables, was deduced from the measured differential-elastic-scattering cross sections. The experimental-results were compared with the respective evaluated quantities given in ENDF/B-V

  13. Fast-neutron total and scattering cross sections of niobium

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.B.; Guenther, P.T.; Whalen, J.F.

    1982-07-01

    Neutron total cross sections of niobium were measured from approx. = 0.7 to 4.5 MeV at intervals of less than or equal to 50 keV with broad resolution. Differential-elastic-scattering cross sections were measured from approx. = 1.5 to 4.0 MeV at intervals of 0.1 to 0.2 MeV and at 10 to 20 scattering angles distributed between approx. = 20 and 160 degrees. Inelastically-scattered neutrons, corresponding to the excitation of levels at: 788 +- 23, 982 +- 17, 1088 +- 27, 1335 +- 35, 1504 +- 30, 1697 +- 19, 1971 +- 22, 2176 +- 28, 2456 +- (.), and 2581 +- (.) keV, were observed. An optical-statistical model, giving a good description of the observables, was deduced from the measured differential-elastic-scattering cross sections. The experimental-results were compared with the respective evaluated quantities given in ENDF/B-V.

  14. Fast-neutron induced background in LaBr{sub 3}:Ce detectors

    Energy Technology Data Exchange (ETDEWEB)

    Kiener, J., E-mail: Jurgen.Kiener@csnsm.in2p3.fr [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), CNRS-IN2P3 et Université Paris-Sud, 91405 Campus Orsay (France); Tatischeff, V.; Deloncle, I. [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), CNRS-IN2P3 et Université Paris-Sud, 91405 Campus Orsay (France); Séréville, N. de [Institut de Physique Nucléaire d' Orsay, CNRS-IN2P3 and Université Paris-Sud, 91406 Orsay (France); Laurent, P. [CEA/IRFU Service d' Astrophysique, Orme des Merisiers, CEA Saclay, 91191 Gif-sur-Yvette (France); Laboratoire Astroparticules et Cosmologie (APC), 10, rue A. Domon et L. Duquet, 75205 Paris (France); Blondel, C. [Laboratoire AIM, CEA/IRFU, Orme des Merisiers, CEA Saclay, 91191 Gif-sur-Yvette (France); Chabot, M. [Institut de Physique Nucléaire d' Orsay, CNRS-IN2P3 and Université Paris-Sud, 91406 Orsay (France); Chipaux, R. [CEA/DMS/IRFU/SEDI, CEA Saclay, 91191 Gif sur Yvette (France); Coc, A. [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), CNRS-IN2P3 et Université Paris-Sud, 91405 Campus Orsay (France); Dubos, S. [Laboratoire AIM, CEA/IRFU, Orme des Merisiers, CEA Saclay, 91191 Gif-sur-Yvette (France); Gostojic, A. [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), CNRS-IN2P3 et Université Paris-Sud, 91405 Campus Orsay (France); and others

    2015-10-21

    The response of a scintillation detector with a cylindrical 1.5-in. LaBr{sub 3}:Ce crystal to incident neutrons has been measured in the energy range E{sub n} = 2–12 MeV. Neutrons were produced by proton irradiation of a Li target at E{sub p} = 5–14.6 MeV with pulsed proton beams. Using the time-of-flight information between target and detector, energy spectra of the LaBr{sub 3}:Ce detector resulting from fast neutron interactions have been obtained at 4 different neutron energies. Neutron-induced γ rays emitted by the LaBr{sub 3}:Ce crystal were also measured in a nearby Ge detector at the lowest proton beam energy. In addition, we obtained data for neutron irradiation of a large-volume high-purity Ge detector and of a NE-213 liquid scintillator detector, both serving as monitor detectors in the experiment. Monte-Carlo type simulations for neutron interactions in the liquid scintillator, the Ge and LaBr{sub 3}:Ce crystals have been performed and compared with measured data. Good agreement being obtained with the data, we present the results of simulations to predict the response of LaBr{sub 3}:Ce detectors for a range of crystal sizes to neutron irradiation in the energy range E{sub n} = 0.5–10 MeV.

  15. Characterization of the internal background for thermal and fast neutron detection with CLLB

    Energy Technology Data Exchange (ETDEWEB)

    Woolf, Richard S., E-mail: richard.woolf@nrl.navy.mil; Phlips, Bernard F.; Wulf, Eric A.

    2016-12-01

    We report on a set of experiments conducted to determine what effects, if any, the internal background in the CLLB scintillation detector has on the thermal neutron detection performance. We conducted source measurements using an unmoderated and moderated {sup 252}Cf neutron/γ-ray source and long (48-h), unshielded and shielded, background measurements to characterize the internal background with and without a source present. These measurements allowed us to determine the 2-d event selections needed to isolate the thermal neutron peak observed in pulse shape vs. energy space and apply those selections to our background measurements. Our results indicate that the thermal neutron detection capabilities of the CLLB are marginally affected by the presence of internal background. An unmoderated 113-µCi {sup 252}Cf source at 15 cm from the detector yields a thermal neutron rate of 8×10{sup −2}/s cm{sup 3}, while moderating the source with 5 cm of polyethylene yields a thermal neutron rate of 5.5×10{sup −1}/s cm{sup 3}. The measured background rate for events that fall within the selected thermal neutron region is 1.2×10{sup −3}/s cm{sup 3}. Lastly, the potential for CLLB for detecting fast neutrons was investigated.

  16. Fast neutron capture and the microscopic isovector optical potential

    International Nuclear Information System (INIS)

    Chakrabarty, D.R.; Gupta, S.K.

    Neutron capture cross-sections are calculated with the direct-semidirect model employing the complex microscopic optical potential recently calculated by Jeukenne, Lejoune and Mahaux. The data for 89 Y, Ce and 208 Pb for Esub(n)=6-16 MeV agree well with the calculation for a twofold increase in the magnitude of the isovector part of the microscopic potential. (auth.)

  17. A high resolution, low background fast neutron spectrometer

    CERN Document Server

    Abdurashitov, J N; Kalikhov, A V; Matushko, V L; Shikhin, A A; Yants, V E; Zaborskaia, O S; Adams, J M; Nico, J S; Thompson, A K

    2002-01-01

    We discuss the possibility to create a spectrometer of full absorption based on liquid scintillator doped with enriched sup 6 Li. Of specific interest, the spectrometer will have energy resolution estimated to lie in the range 5-10% for 14 MeV neutrons. It will be sensitive to fluxes from 10 sup - sup 4 to 10 sup 6 cm sup - sup 2 s sup - sup 1 above a threshold of 1 MeV in a gamma-background of up to 10 sup 4 s sup - sup 1. The detector's efficiency will be determined by the volume of the scintillator only (approx 3 l) and is estimated to be 0.2-10%. The main reason for the poor resolution of an organic scintillator based spectrometer of full absorption is a non-linear light-yield of the scintillator for recoil protons. The neutron energy is occasionally distributed among recoil protons, and due to non-linear light-yield the total amount of light from all recoil protons ambiguously determines the initial neutron energy. The high-energy resolution will be achieved by compensation of the non-linear light-yield ...

  18. Fast neutron background characterization with the Radiological Multi-sensor Analysis Platform (RadMAP)

    Energy Technology Data Exchange (ETDEWEB)

    Davis, John R., E-mail: john.davis@usma.edu [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); The United States Military Academy, West Point, NY (United States); Brubaker, Erik [Sandia National Laboratories, Livermore, CA (United States); Vetter, Kai [Lawrence Berkeley National Laboratory, Berkeley, CA (United States)

    2017-06-21

    In an effort to characterize the fast neutron radiation background, 16 EJ-309 liquid scintillator cells were installed in the Radiological Multi-sensor Analysis Platform (RadMAP) to collect data in the San Francisco Bay Area. Each fast neutron event was associated with specific weather metrics (pressure, temperature, absolute humidity) and GPS coordinates. The expected exponential dependence of the fast neutron count rate on atmospheric pressure was demonstrated and event rates were subsequently adjusted given the measured pressure at the time of detection. Pressure adjusted data was also used to investigate the influence of other environmental conditions on the neutron background rate. Using National Oceanic and Atmospheric Administration (NOAA) coastal area lidar data, an algorithm was implemented to approximate sky-view factors (the total fraction of visible sky) for points along RadMAPs route. Three areas analyzed in San Francisco, Downtown Oakland, and Berkeley all demonstrated a suppression in the background rate of over 50% for the range of sky-view factors measured. This effect, which is due to the shielding of cosmic-ray produced neutrons by surrounding buildings, was comparable to the pressure influence which yielded a 32% suppression in the count rate over the range of pressures measured.

  19. Application of semiconductors for dosimetry of fast-neutron therapy beam

    International Nuclear Information System (INIS)

    Yudelev, M.; Alyousef, K.; Brandon, J.; Perevertailo, V.; Lerch, M. L. F.; Rosenfeld, A. B.

    2004-01-01

    Two types of ion implanted miniature p-i-n diodes were tested in a d(48.5) + Be fast-neutron beam produced in the Detroit superconducting cyclotron. The increase in forward voltage drop caused by neutron-induced damage was correlated with neutron dose measured in a water phantom. The neutron and gamma dose components were predetermined using twin detector (Tissue-equivalent ion chamber paired with miniature Geiger-Mueller counter) method. The increase in the voltage drop for 1 mA injection current was monitored together with the cyclotron beam target current, thus the differential voltage drop could be defined precisely for given radiation dose. The average neutron sensitivities of tested diodes were 1.284 ± 0.014 and 0.528 ± 0.058 mV per cGy. The miniature detectors can be utilised in characterisation of small radiation fields and in the regions of high dose gradient as well as for in vivo dosimetry of the patients undergoing fast-neutron therapy. (authors)

  20. Estimation of fast neutron fluence in steel specimens type Laguna Verde in TRIGA Mark III reactor

    International Nuclear Information System (INIS)

    Galicia A, J.; Francois L, J. L.; Aguilar H, F.

    2015-09-01

    The main purpose of this work is to obtain the fluence of fast neutrons recorded within four specimens of carbon steel, similar to the material having the vessels of the BWR reactors of the nuclear power plant of Laguna Verde when subjected to neutron flux in a experimental facility of the TRIGA Mark III reactor, calculating an irradiation time to age the material so accelerated. For the calculation of the neutron flux in the specimens was used the Monte Carlo code MCNP5. In an initial stage, three sheets of natural molybdenum and molybdenum trioxide (MoO 3 ) were incorporated into a model developed of the TRIGA reactor operating at 1 M Wth, to calculate the resulting activity by setting a certain time of irradiation. The results obtained were compared with experimentally measured activities in these same materials to validate the calculated neutron flux in the model used. Subsequently, the fast neutron flux received by the steel specimens to incorporate them in the experimental facility E-16 of the reactor core model operating at nominal maximum power in steady-state was calculated, already from these calculations the irradiation time required was obtained for values of the neutron flux in the range of 10 18 n/cm 2 , which is estimated for the case of Laguna Verde after 32 years of effective operation at maximum power. (Author)

  1. The fast neutron response of 7LiF thermoluminescent dosemeters

    International Nuclear Information System (INIS)

    Knipe, A.D.

    1990-02-01

    A series of experiments was performed in 1982 to determine the neutron energy response of the 7 LiF thermoluminescent dosemeter (TLD) employed in European zero power fast reactor gamma-ray energy deposition studies. Preliminary results of this work were included in a 1985 International experimental data-base of TLD neutron sensitivities and provided the most consistent set of data within the 7 LiF compilation. A more detailed interpretation of these data has improved the results still further, giving a mean relative neutron to gamma efficiency of 0.118±0.005. The main objective of this re-evaluation was to establish recommended neutron energy response values to replace a 1974 data set for the analysis of in-core fast reactor measurements. This was achieved by combining the mean experimental relative efficiency of 0.118 with calculated energy dependent kerma factors. The kerma factors for the TLD were based on US National Bureau of Standards values and a composition determined by chemical analysis. Adoption of the revised neutron energy response data set produces a small increase in the measured gamma-ray energy deposition of typically 2% relative to the 1974 data. However, more importantly, the detailed analysis of the experimental response data has significantly improved confidence in the neutron corrections applied to in-core TLD gamma-ray energy deposition measurements. (author)

  2. Fast neutron detection with {sup 6}Li-loaded liquid scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, B.M., E-mail: brian.fisher@jhuapl.edu [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Abdurashitov, J.N. [Institute for Nuclear Research, Russian Academy of Sciences, Moscow 117312 (Russian Federation); Coakley, K.J. [National Institute of Standards and Technology, Boulder, CO 80305 (United States); Gavrin, V.N. [Institute for Nuclear Research, Russian Academy of Sciences, Moscow 117312 (Russian Federation); Gilliam, D.M. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Nico, J.S., E-mail: jnico@nist.gov [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Shikhin, A.A. [Institute for Nuclear Research, Russian Academy of Sciences, Moscow 117312 (Russian Federation); Thompson, A.K. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Vecchia, D.F. [National Institute of Standards and Technology, Boulder, CO 80305 (United States); Yants, V.E. [Institute for Nuclear Research, Russian Academy of Sciences, Moscow 117312 (Russian Federation)

    2011-08-01

    We report on the development of a fast neutron detector using a liquid scintillator doped with enriched {sup 6}Li. The lithium was introduced in the form of an aqueous LiCl micro-emulsion with a di-isopropylnaphthalene-based liquid scintillator. A {sup 6}Li concentration of 0.15% by weight was obtained. A 125 mL glass cell was filled with the scintillator and irradiated with fission-source neutrons. Fast neutrons may produce recoil protons in the scintillator, and those neutrons that thermalize within the detector volume can be captured on the {sup 6}Li. The energy of the neutron may be determined by the light output from recoiling protons, and the capture of the delayed thermal neutron reduces background events. In this paper, we discuss the development of this {sup 6}Li-loaded liquid scintillator, demonstrate the operation of it in a detector, and compare its efficiency and capture lifetime with Monte Carlo simulations. Data from a boron-loaded plastic scintillator were acquired for comparison. We also present a pulse-shape discrimination method for differentiating between electronic and nuclear recoil events based on the Matusita distance between a normalized observed waveform and nuclear and electronic recoil template waveforms. The details of the measurements are discussed along with specifics of the data analysis and its comparison with the Monte Carlo simulation.

  3. Advanced Multilayer Composite Heavy-Oxide Scintillator Detectors for High Efficiency Fast Neutron Detection

    Science.gov (United States)

    Ryzhikov, Vladimir D.; Naydenov, Sergei V.; Pochet, Thierry; Onyshchenko, Gennadiy M.; Piven, Leonid A.; Smith, Craig F.

    2018-01-01

    We have developed and evaluated a new approach to fast neutron and neutron-gamma detection based on large-area multilayer composite heterogeneous detection media consisting of dispersed granules of small-crystalline scintillators contained in a transparent organic (plastic) matrix. Layers of the composite material are alternated with layers of transparent plastic scintillator material serving as light guides. The resulting detection medium - designated as ZEBRA - serves as both an active neutron converter and a detection scintillator which is designed to detect both neutrons and gamma-quanta. The composite layers of the ZEBRA detector consist of small heavy-oxide scintillators in the form of granules of crystalline BGO, GSO, ZWO, PWO and other materials. We have produced and tested the ZEBRA detector of sizes 100x100x41 mm and greater, and determined that they have very high efficiency of fast neutron detection (up to 49% or greater), comparable to that which can be achieved by large sized heavy-oxide single crystals of about Ø40x80 cm3 volume. We have also studied the sensitivity variation to fast neutron detection by using different types of multilayer ZEBRA detectors of 100 cm2 surface area and 41 mm thickness (with a detector weight of about 1 kg) and found it to be comparable to the sensitivity of a 3He-detector representing a total cross-section of about 2000 cm2 (with a weight of detector, including its plastic moderator, of about 120 kg). The measured count rate in response to a fast neutron source of 252Cf at 2 m for the ZEBRA-GSO detector of size 100x100x41 mm3 was 2.84 cps/ng, and this count rate can be doubled by increasing the detector height (and area) up to 200x100 mm2. In summary, the ZEBRA detectors represent a new type of high efficiency and low cost solid-state neutron detector that can be used for stationary neutron/gamma portals. They may represent an interesting alternative to expensive, bulky gas counters based on 3He or 10B neutron

  4. Emergency cooling down of fast-neutron reactors by natural convection (a review)

    Science.gov (United States)

    Zhukov, A. V.; Sorokin, A. P.; Kuzina, Yu. A.

    2013-05-01

    Various methods for emergency cooling down of fast-neutron reactors by natural convection are discussed. The effectiveness of using natural convection for these purposes is demonstrated. The operating principles of different passive decay heat removal systems intended for cooling down a reactor are explained. Experimental investigations carried out in Russia for substantiating the removal of heat in cooling down fast-neutron reactors are described. These investigations include experimental works on studying thermal hydraulics in small-scale simulation facilities containing the characteristic components of a reactor (reactor core elements, above-core structure, immersed and intermediate heat exchangers, pumps, etc.). It is pointed out that a system that uses leaks of coolant between fuel assemblies holds promise for fast-neutron reactor cooldown purposes. Foreign investigations on this problem area are considered with making special emphasis on the RAMONA and NEPTUN water models. A conclusion is drawn about the possibility of using natural convection as the main method for passively removing heat in cooling down fast-neutron reactors, which is confirmed experimentally both in Russia and abroad.

  5. Fast neutron induced structural rearrangements at a soybean NAP1 locus result in gnarled trichomes

    Science.gov (United States)

    A soybean (Glycine max (L.) Merr.) gnarled trichome mutant, exhibiting stunted trichomes compared to wild-type, was identified in a fast neutron mutant population. Genetic mapping using whole genome sequence-based bulked segregant analysis identified a 26.6 megabase interval on chromosome 20 that ...

  6. Fast neutron mutants database and web displays at SoyBase

    Science.gov (United States)

    SoyBase, the USDA-ARS soybean genetics and genomics database, has been expanded to include data for the fast neutron mutants produced by Bolon, Vance, et al. In addition to the expected text and sequence homology searches and visualization of the indels in the context of the genome sequence viewer, ...

  7. Fast neutron radiation induced Glu-B1 deficient lines of an elite bread wheat variety

    Science.gov (United States)

    Five isogenic wheat lines deficient in high-molecular weight subunit (HMW-GS) proteins encoded by the B-genome were identified from a fast-neutron radiation-mutagenized population of Summit, an elite variety of bread wheat (Triticum aestivum L.). The mutant lines differ from the wild-type progenit...

  8. In-Pile Qualification of the Fast-Neutron-Detection-System

    Directory of Open Access Journals (Sweden)

    Fourmentel D.

    2018-01-01

    FNDS has been validated through a two-step experimental program. A first set of tests was performed at BR2 reactor operated by SCK•CEN in Belgium. Then a second test was recently completed at ISIS reactor operated by CEA in France. FNDS proved its ability to measure online the fast neutron flux with an overall accuracy better than 5%.

  9. Properties and mechanical behaviour of fuel cans of fast neutron reactors

    International Nuclear Information System (INIS)

    Cauvin, R.; Boutard, J.L.

    1983-06-01

    Mechanical properties of Stainless steel-316 irradiated up to 100 dpa in fast neutron reactors are examined. Microscopic phenomena involved are reviewed: precipitation, segregation, dislocations, vacancies. Influence on mechanical behaviour of materials are examined: tensile properties, creep, ductility. Consequences on reactor dimensioning are given in conclusion [fr

  10. The Effect Of Beryllium Interaction With Fast Neutrons On the Reactivity Of ETRR-2 Research Reactor

    International Nuclear Information System (INIS)

    Aziz, M.; El Messiry, A.M.

    2000-01-01

    The effect of beryllium interactions with fast neutrons is studied for Etrr 2 research reactors. Isotope build up inside beryllium blocks is calculated under different irradiation times. a new model for the Etrr 2 research reactor is designed using MCNP code to calculate the reactivity and flux change of the reactor due to beryllium poison

  11. Measured thermal and fast neutron fluence rates for ATF-1 holders during ATR cycle 160A

    Energy Technology Data Exchange (ETDEWEB)

    Walker, B. J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Miller, D. T. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-06-06

    This report contains the thermal (2200 m/s) and fast (E>1MeV) neutron fluence rate data for the ATF-1 holders located in core for ATR Cycle 160A which were measured by the Radiation Measurements Laboratory (RML).

  12. HADES. A computer code for fast neutron cross section from the Optical Model

    International Nuclear Information System (INIS)

    Guasp, J.; Navarro, C.

    1973-01-01

    A FORTRAN V computer code for UNIVAC 1108/6 using a local Optical Model with spin-orbit interaction is described. The code calculates fast neutron cross sections, angular distribution, and Legendre moments for heavy and intermediate spherical nuclei. It allows for the possibility of automatic variation of potential parameters for experimental data fitting. (Author) 55 refs

  13. Somatic mutation and recombination induced by fast neutrons in the wing spot test of Drosophila Melanogaster

    International Nuclear Information System (INIS)

    Guzman R, J.; Varela, A.; Policroniades, R.; Delfin, A.; Graf, U.

    1994-01-01

    In the last decades, a large number of studies have been undertaken to evaluate the biological effects of gamma and X rays in Drosophila melanogaster. The majority of these investigations were performed on female and male germ cells. However, comparatively little is known in relation to the biological effects of fast neutrons, and especially in relation to their effects in somatic cells. (Author)

  14. The mutagenic effect of streptomyces and aspergillus niger with fast neutron irradiation

    International Nuclear Information System (INIS)

    Zhang Shengjun; Zhou Shuxin; Fang Xiaoming

    1992-01-01

    The authors describe the effect of irradiation on some Streptomyces and Aspergillus niger with fast neutron. The death rate(%), production rate(%, W/V), and heredities were determined and analysed. Particularly, five variant types of Strepto. griseous No.1 will be researched in depth

  15. Stilbene crystalline powder in polymer base as a new fast neutron detector

    International Nuclear Information System (INIS)

    Budakovsky, S.V.; Galunov, N.Z.; Grinyov, B.V.; Karavaeva, N.L.; Kyung Kim, Jong; Kim, Yong-Kyun; Pogorelova, N.V.; Tarasenko, O.A.

    2007-01-01

    A new organic scintillation material consisting of stilbene grains in a polymer glue base is presented. The crystalline grains of stilbene are obtained by mechanical grinding of stilbene single crystals. The resulting composite scintillators have been studied as detectors for fast neutrons

  16. Gastrocutaneous fistula as a late complication of fast neutron therapy for carcinoma of the stomach

    International Nuclear Information System (INIS)

    Griffith, C.D.M.; Arnott, S.J.

    1984-01-01

    A brief report is presented of a case of gastrocutaneous fistula in a 36-year-old housewife, who had been treated a year previously for carcinoma of the stomach with fast neutron therapy at a dose of 1500 cGy delivered in 20 daily treatments. The maximum tissue dose delivered to the skin surface was 1780 cGy. (U.K.)

  17. Induction of mutations in antibiotic-producing microorganisms by fast neutrons from the U-120 cyclotron

    International Nuclear Information System (INIS)

    Wolf, J.; Huczkowski, J.; Siejka, D.; Krasnowolski, S.; Brodowicz, M.

    1976-01-01

    The purpose of this study was to investigate the activity of fast neutrons from a U-120 cyclotron in the induction of mutations in streptomycetes, resulting in strains with enhanced antibiotic production. Three streptomycete strains producing the antibiotics: lincomycin, moenomycin, and demethylchlorotetracycline were used. Correlation between the survival rate of spores of the examined strains and neutron dose was determined. Several morphological and physiological features (particularly production of antibiotics for 1543 variants derived from the parent strains) and their distribution within the population were also studied. The survival rate of the streptomycetes spores after irradiation with fast neutrons was found to be an individual strain property. Several variants with considerably increased antibiotic yield were isolated. The results are compared with those obtained after treatment with other mutagens. Several variants of one of the strains with a strongly enhanced antibiotic yield (200-220%) were isolated. No such variants were found after UV irradiation. (author)

  18. Environmental protection problems from the standpoint of regeneration of fast neutron reactor fuel

    International Nuclear Information System (INIS)

    Gedeonov, L.I.; Lazarev, L.N.; Suprunenko, A.N.

    The discussion of the problem of environmental protection is based on two principles: a strict observance of legislatively established standards for permissible concentrations of radionuclides in objects of the environment and for dose loads for the population; all possible steps to reduce the contamination to a level justified in practice. Environmental protection steps are considered from the points of view of a systematic analysis. A survey of the environmental protection system near sources of radioactive discharges is given. The basic interactions and feedbacks are indicated. Characteristics differentiating the discharges of the fuel cycle of fast neutron breeder reactors from discharges of the slow neutron cycle are discussed. It is shown that it is necessary to study the overall regional and global interactions of discharges of the atomic power industry. The characteristics of situations at nuclear fuel cycle facilities of fast neutron reactors are discussed. The necessity of additional technical steps to prevent accidents and eliminate their effects if they take place is emphasized

  19. Study irradiation damage by fast neutrons in Portland cement by means of ultra-sound

    International Nuclear Information System (INIS)

    Rosa Junior, A.A.

    1988-01-01

    The effect of neutron irradiation in samples of Portland cement paste was evaluated, using the resonance frequency method and pulse velocity of ultra-sound technique. The samples were divide in three groups: 1) Monitoring samples; 2) Samples to gamma heating simulation; 3) Fast neutron irradiated samples in reactor core. Santa Rita Portland cement was utilized for samples preparation with water-cement rate of 0,40 l/kg. The irradiation was performed in the research reactor IEA-R1, at IPEN-CNEN/SP, with an integrated flux of 7,2 X 10 sup(18) n/cm sup(2) (E approx. 1 Mev). The samples of group 2 were submitted to special micro-waves heat treatment-with the same number of cycles of the reactor-which allowed the detection of fast neutron radiation effects within the predominant thermal effects. (author)

  20. Fast-neutron scattering cross sections of elemental zirconium

    International Nuclear Information System (INIS)

    Smith, A.B.; Guenther, P.T.

    1982-12-01

    Differential neturon-elastic-scattering cross sections of elemental zirconium are measured from 1.5 to 4.0 MeV at intervals of less than or equal to 200 keV. Inelastic-neutron-scattering cross sections corresponding to the excitation of levels at observed energies of: 914 +- 25, 1476 +- 37, 1787 +- 23, 2101 +- 26, 2221 +- 17, 2363 +- 14, 2791 +- 15 and 3101 +- 25 keV are determined. The experimental results are interpreted in terms of the optical-statistical model and are compared with corresponding quantities given in ENDF/B-V

  1. Digital pulse shape discrimination between fast neutrons and gamma rays with para-terphenyl scintillator

    Science.gov (United States)

    Chepurnov, A. S.; Kirsanov, M. A.; Klenin, A. A.; Klimanov, S. G.; Kubankin, A. S.

    2017-12-01

    In the presented work, we investigated several digital methods of a discrimination signals from fast neutrons and gamma quanta. The experimental setup consists of a Pu-Be neutron source, a scintillation detector with an organic para-terphenyl monocrystal, and a digitizer (CAEN DT5730, 500 MS/s). Mixed waveform sequences were stored and then separated by pulse shape. Four methods were used for signals separation. Comparison of the traditional and the new methods of Figure of Merit (FOM) calculation is given. FOM = 1.5 was obtained in our setup for the minimum threshold value. A scintillation detector with a para-terphenyl crystal was used to measure neutron yield in the neutron generator with carbon nanotubes.

  2. Neutron spectroscopy measurements and modeling of neutral beam heating fast ion dynamics

    International Nuclear Information System (INIS)

    Hellesen, C; Sunden, E Andersson; Conroy, S; Ericsson, G; Johnson, M Gatu; Hjalmarsson, A; Kaellne, J; Ronchi, E; Sjoestrand, H; Weiszflog, M; Albergante, M; Ballabio, L; Gorini, G; Tardocchi, M; Giacomelli, L; Jenkins, I; Voitsekhovitch, I

    2010-01-01

    The energy spectrum of the neutron emission from beam-target reactions in fusion plasmas at the Joint European Torus (JET) has been investigated. Different beam energies as well as injection angles were used. Both measurements and simulations of the energy spectrum were done. The measurements were made with the time-of-flight spectrometer TOFOR. Simulations of the neutron spectrum were based on first-principle calculations of neutral beam deposition profiles and the fast ion slowing down in the plasma using the code NUBEAM, which is a module of the TRANSP package. The shape of the neutron energy spectrum was seen to vary significantly depending on the energy of the beams as well as the injection angle and the deposition profile in the plasma. Cross validations of the measured and modeled neutron energy spectra were made, showing a good agreement for all investigated scenarios.

  3. Fast neutron inspection of sea containers for the presence of 'dirty bomb'

    International Nuclear Information System (INIS)

    Valkovic, V.; Sudac, D.; Blagus, S.; Nad, K.; Obhodas, J.; Vekic, B.; Nebbia, G.; Pesente, S.

    2007-01-01

    The possibility of the detection of 'dirty bomb' presence inside sea containers is evaluated. The method proposed for explosive and fissile material detection makes use of two sensors (X-rays and neutrons). A commercial imaging device based on the X-ray radiography performs a fast scan of the container, identifies a 'suspect' region and provides its coordinates to the neutron based device for the final 'confirmatory' inspection. In this two sensor system a 14 MeV neutron beam defined by the detection of associated alpha particles is used for interrogation of only volume elements marked by X-ray sensor. The object's nature is determined from passive and neutron induced, gamma energy spectra measurements. Experimental results (time-of-flight and gamma energy spectra) obtained for the irradiation 30 kg of TNT, depleted uranium and other materials hidden inside the container are presented

  4. Fast-neutron interaction with collective cadmium nuclei

    International Nuclear Information System (INIS)

    Smith, A.B.; Guenther, P.T.

    1992-11-01

    Differential neutron elastic-scattering cross sections of elemental cadmium are measured from ∼ 1.5 to 10 MeV. From ∼ 1.5 to 3.0 MeV the measurements are made at ∼ 100 keV incident-neutron energy intervals and at 10 scattering angles distributed between ∼ 200 and 160 degree. From 3 to 4 MeV the measurements are made at ∼ 200 MeV intervals and at 20 angles. Above 4 MeV the incident-energy interval is ∼ 0.5 MeV with ≥ 40 differential values at each incident energy, distributed between ∼ 18 and 160 degree. Concurrently, differential cross sections for the excitation of observed ''levels'' at 0.589 ± 0.047, 1.291 ± 0.066 and 1.839 ± 0.57 MeV are determined, with attention to the direct excitation of the yrast 2 + levels of the even isotopes (∼ 75% abundant) and of the 3/2 + and 5/2 + levels of the odd isotopes (∼ 75% abundant). Optical-statistical, dispersive-optical and coupled-channels interpretations are carried out and comparisons made with ''regional'' and ''global'' parameters. Consideration is given to the fundamental nature of the real potential in the vicinity of the Fermi Surface with implications on the equation of state and the reduced mass, in the context of the dispersive optical model

  5. SPECTRUM WEIGHTED RESPONSES OF SEVERAL DETECTORS IN MIXED FIELDS OF FAST AND THERMAL NEUTRONS

    Directory of Open Access Journals (Sweden)

    SANG IN KIM

    2014-04-01

    Full Text Available The spectrum weighted responses of various detectors were calculated to provide guidance on the proper selection and use of survey instruments on the basis of their energy response characteristics on the neutron fields. To yield the spectrum weighted response, the detector response functions of 17 neutron-measuring devices were numerically folded with each of the produced calibration neutron spectra through the in-house developed software ‘K-SWR’. The detectors’ response functions were taken from the IAEA Technical Reports Series No. 403 (TRS-403. The reference neutron fields of 21 kinds with 2 spectra groups with different proportions of thermal and fast neutrons have been produced using neutrons from the 241Am-Be sources held in a graphite pile, a bare 241Am-Be source, and a DT neutron generator. Fluence-average energy (Eave varied from 3.8 MeV to 16.9 MeV, and the ambient-dose-equivalent rate [H*(10/h] varied from 0.99 to 16.5 mSv/h.

  6. Two reports: (i) Correlation properties of delayed neutrons from fast neutron induced fission. (ii) Method and set-up for measurements of trace level content of heavy fissionable elements based on delayed neutron counting

    International Nuclear Information System (INIS)

    Piksaikin, V.M.; Isaev, S.G.; Goverdovski, A.A.; Pshakin, G.M.

    1998-10-01

    The document includes the following two reports: 'Correlation properties of delayed neutrons from fast neutron induced fission' and 'Method and set-up for measurements of trace level content of heavy fissionable elements based on delayed neutron counting. A separate abstract was prepared for each report

  7. Measurements of effective delayed neutron fraction in a fast neutron reactor using the perturbation method

    Science.gov (United States)

    Zhou, Hao-Jun; Yin, Yan-Peng; Fan, Xiao-Qiang; Li, Zheng-Hong; Pu, Yi-Kang

    2016-06-01

    A perturbation method is proposed to obtain the effective delayed neutron fraction β eff of a cylindrical highly enriched uranium reactor. Based on reactivity measurements with and without a sample at a specified position using the positive period technique, the reactor reactivity perturbation Δρ of the sample in β eff units is measured. Simulations of the perturbation experiments are performed using the MCNP program. The PERT card is used to provide the difference dk of effective neutron multiplication factors with and without the sample inside the reactor. Based on the relationship between the effective multiplication factor and the reactivity, the equation β eff = dk/Δρ is derived. In this paper, the reactivity perturbations of 13 metal samples at the designable position of the reactor are measured and calculated. The average β eff value of the reactor is given as 0.00645, and the standard uncertainty is 3.0%. Additionally, the perturbation experiments for β eff can be used to evaluate the reliabilities of the delayed neutron parameters. This work shows that the delayed neutron data of 235U and 238U from G.R. Keepin’s publication are more reliable than those from ENDF-B6.0, ENDF-B7.0, JENDL3.3 and CENDL2.2. Supported by Foundation of Key Laboratory of Neutron Physics, China Academy of Engineering Physics (2012AA01, 2014AA01), National Natural Science Foundation (11375158, 91326104)

  8. Testing plutonium fuel assembly production for fast-neutron reactors

    International Nuclear Information System (INIS)

    Nougues, B.; Benhamou, A.; Bertothy, G.; Lepetit, H.

    1975-01-01

    The main characteristics of plutonium fuel elements for fast breeder reactors justify specific test procedures and special techniques. The specific tests relating to the Pu content consist of Pu enrichment and distribution tests, determination of the O/M ratio and external contamination tests. The specific tests performed on fuel configuration are: testing of sintered pellet diameter, testing of pin welding and checking of internal assmbly [fr

  9. Nuclear Waste Removal Using Particle Beams Incineration with Fast Neutrons

    CERN Document Server

    Revol, Jean Pierre Charles

    1997-01-01

    The management of nuclear waste is one of the major obstacles to the acceptability of nuclear power as a main source of energy for the future. TARC, a new experiment at CERN, is testing the practicality of Carlo Rubbia's idea to make use of Adiabatic Resonance Crossing to transmute long-lived fission fragments into short-lived or stable nuclides. Spallation neutrons produced in a large Lead assembly have a high probability to be captured at the energies of cross-section resonances in elements such as 99Tc, 129I, etc. An accelerator-driven sub-critical device using Thorium (Energy Amplifier) would be very effective in eliminating TRansUranic elements which constitute the most dangerous part of nuclear waste while producing from it large amounts of energy. In addition, such a system could transform, at a high rate and little energetic cost, long-lived fission fragments into short-lived elements.

  10. Fast-neutron interaction with collective cadmium nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.B.; Guenther, P.T.

    1992-11-01

    Differential neutron elastic-scattering cross sections of elemental cadmium are measured from [approx] 1.5 to 10 MeV. From [approx] 1.5 to 3.0 MeV the measurements are made at [approx] 100 keV incident-neutron energy intervals and at 10 scattering angles distributed between [approx] 200 and 160[degree]. From 3 to 4 MeV the measurements are made at [approx] 200 MeV intervals and at 20 angles. Above 4 MeV the incident-energy interval is [approx] 0.5 MeV with [ge] 40 differential values at each incident energy, distributed between [approx] 18 and 160[degree]. Concurrently, differential cross sections for the excitation of observed levels'' at 0.589 [plus minus] 0.047, 1.291 [plus minus] 0.066 and 1.839 [plus minus] 0.57 MeV are determined, with attention to the direct excitation of the yrast 2[sup +] levels of the even isotopes ([approx] 75% abundant) and of the 3/2[sup +] and 5/2[sup +] levels of the odd isotopes ([approx] 75% abundant). Optical-statistical, dispersive-optical and coupled-channels interpretations are carried out and comparisons made with regional'' and global'' parameters. Consideration is given to the fundamental nature of the real potential in the vicinity of the Fermi Surface with implications on the equation of state and the reduced mass, in the context of the dispersive optical model.

  11. Fast-neutron interaction with collective cadmium nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.B.; Guenther, P.T.

    1992-11-01

    Differential neutron elastic-scattering cross sections of elemental cadmium are measured from {approx} 1.5 to 10 MeV. From {approx} 1.5 to 3.0 MeV the measurements are made at {approx} 100 keV incident-neutron energy intervals and at 10 scattering angles distributed between {approx} 200 and 160{degree}. From 3 to 4 MeV the measurements are made at {approx} 200 MeV intervals and at 20 angles. Above 4 MeV the incident-energy interval is {approx} 0.5 MeV with {ge} 40 differential values at each incident energy, distributed between {approx} 18 and 160{degree}. Concurrently, differential cross sections for the excitation of observed ``levels`` at 0.589 {plus_minus} 0.047, 1.291 {plus_minus} 0.066 and 1.839 {plus_minus} 0.57 MeV are determined, with attention to the direct excitation of the yrast 2{sup +} levels of the even isotopes ({approx} 75% abundant) and of the 3/2{sup +} and 5/2{sup +} levels of the odd isotopes ({approx} 75% abundant). Optical-statistical, dispersive-optical and coupled-channels interpretations are carried out and comparisons made with ``regional`` and ``global`` parameters. Consideration is given to the fundamental nature of the real potential in the vicinity of the Fermi Surface with implications on the equation of state and the reduced mass, in the context of the dispersive optical model.

  12. Trends and Developments for Fast Neutron Reactors and Related Fuel Cycles

    International Nuclear Information System (INIS)

    Carré, Frank

    2013-01-01

    • FR13 – A unique and dedicated framework to share updates on national programs of Fast Reactor developments, projects of new builds and plans for the future: - Near term projects of sodium and lead-alloy Fast Reactors; - Gen-IV visions of sodium-cooled and alternative types of Fast Neutron Reactors (GFR, LFR…). • FR13 – A special emphasis put on Fast Reactor Safety, Sustainability of nuclear fuel cycle and Young Generation perspective. • FR13 – A catalyst for further collaborations and alliances: - To share visions of goals and advisable options for future Fast Reactors and Nuclear Fuel Cycle; - To share cost of R&D and large demonstrations (safety, security, recycling); - To progress towards harmonized international standards; - To integrate national projects into a consistent international roadmap

  13. Fast neutron detection at near-core location of a research reactor with a SiC detector

    Science.gov (United States)

    Wang, Lei; Jarrell, Josh; Xue, Sha; Tan, Chuting; Blue, Thomas; Cao, Lei R.

    2018-04-01

    The measurable charged-particle produced from the fast neutron interactions with the Si and C nucleuses can make a wide bandgap silicon carbide (SiC) sensor intrinsically sensitive to neutrons. The 4H-SiC Schottky detectors have been fabricated and tested at up to 500 °C, presenting only a slightly degraded energy resolution. The response spectrum of the SiC detectors were also obtained by exposing the detectors to external neutron beam irradiation and at a near-core location where gamma-ray field is intense. The fast neutron flux of these two locations are ∼ 4 . 8 × 104cm-2 ṡs-1 and ∼ 2 . 2 × 107cm-2 ṡs-1, respectively. At the external beam location, a Si detector was irradiated side-by-side with SiC detector to disjoin the neutron response from Si atoms. The contribution of gamma ray, neutron scattering, and charged-particles producing reactions in the SiC was discussed. The fast neutron detection efficiencies were determined to be 6 . 43 × 10-4 for the external fast neutron beam irradiation and 6 . 13 × 10-6 for the near-core fast neutron irradiation.

  14. Fast neutron-gamma discrimination on neutron emission profile measurement on JT-60U

    International Nuclear Information System (INIS)

    Ishii, K.; Okamoto, A.; Kitajima, S.; Sasao, M.; Shinohara, K.; Ishikawa, M.; Baba, M.; Isobe, M.

    2010-01-01

    A digital signal processing (DSP) system is applied to stilbene scintillation detectors of the multichannel neutron emission profile monitor in JT-60U. Automatic analysis of the neutron-γ pulse shape discrimination is a key issue to diminish the processing time in the DSP system, and it has been applied using the two-dimensional (2D) map. Linear discriminant function is used to determine the dividing line between neutron events and γ-ray events on a 2D map. In order to verify the validity of the dividing line determination, the pulse shape discrimination quality is evaluated. As a result, the γ-ray contamination in most of the beam heating phase was negligible compared with the statistical error with 10 ms time resolution.

  15. A fast neutron spectrum unfolding method using activation measurements and its application of restoration of a thermonuclear reactor blanket neutron spectrum

    International Nuclear Information System (INIS)

    Novikov, V.M.; Shkurpelov, A.A.; Zagryadsky, V.A.; Chuvilin, D.Yu.; Shmonin, Yu.V.

    1982-01-01

    This article describes a fast neutron spectrum unfolding program. The program takes into account a priori information about the neutron spectrum, the experimental values of activation integrals errors and activation detector cross sections errors. The usefulness of the unfolding program was demonstrated by its application to the determination of neutron spectra from 1 to 14 MeV in the molten-salt blanket model of a thermonuclear reactor. (orig.)

  16. Definition and validation of a calculation method (neutronic formulaire) used to investigate the properties of fast neutron reactor blankets

    International Nuclear Information System (INIS)

    Soule, Roland.

    1982-10-01

    This thesis presents basic cross section data set processing and flux distribution methods (''formulaire''), which may be used to calculate the properties of fast neutron reactor blankets. This formulaire is a part of the global calculation method used to study the whole reactor core. The approach adopted consists in studying successively: - the approximations of the multigroup cross sections processing methods and of the spatial and energy neutron flux calculation methods, together with their validation, based on calculation/experiment comparison; - the consequences of the basic data uncertainties on blanket integral parameters calculations. Finally, we apply the formulaire to the analysis of an experiment performed in the PHENIX power reactor (Pu production measurement in the first fertile subassembly ring) [fr

  17. A directional fast neutron detector using scintillating fibers and an intensified CCD camera system

    International Nuclear Information System (INIS)

    Holslin, Daniel; Armstrong, A.W.; Hagan, William; Shreve, David; Smith, Scott

    1994-01-01

    We have been developing and testing a scintillating fiber detector (SFD) for use as a fast neutron sensor which can discriminate against neutrons entering at angles non-parallel to the fiber axis (''directionality''). The detector/convertor component is a fiber bundle constructed of plastic scintillating fibers each measuring 10 cm long and either 0.3 mm or 0.5 mm in diameter. Extensive Monte Carlo simulations were made to optimize the bundle response to a range of fast neutron energies and to intense fluxes of high energy gamma-rays. The bundle is coupled to a set of gamma-ray insenitive electro-optic intensifiers whose output is viewed by a CCD camera directly coupled to the intensifiers. Two types of CCD cameras were utilized: 1) a standard, interline RS-170 camera with electronic shuttering and 2) a high-speed (up to 850 frame/s) field-transfer camera. Measurements of the neutron detection efficiency and directionality were made using 14 MeV neutrons, and the response to gamma-rays was performed using intense fluxes from radioisotopic sources (up to 20 R/h). Recently, the detector was constructed and tested using a large 10 cm by 10 cm square fiber bundle coupled to a 10 cm diameter GEN I intensifier tube. We present a description of the various detector systems and report the results of experimental tests. ((orig.))

  18. Standard Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of Copper

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This test method covers procedures for measuring reaction rates by the activation reaction 63Cu(n,α)60Co. The cross section for 60Co produced in this reaction increases rapidly with neutrons having energies greater than about 5 MeV. 60Co decays with a half-life of 1925.27 days (±0.29 days)(1) and emits two gamma rays having energies of 1.1732278 and 1.332492 MeV (1). The isotopic content of natural copper is 69.17 % 63Cu and 30.83 % 65Cu (2). The neutron reaction, 63Cu(n,γ)64Cu, produces a radioactive product that emits gamma rays which might interfere with the counting of the 60Co gamma rays. 1.2 With suitable techniques, fission-neutron fluence rates above 109 cm−2·s−1 can be determined. The 63Cu(n,α)60Co reaction can be used to determine fast-neutron fluences for irradiation times up to about 15 years (for longer irradiations, see Practice E261). 1.3 Detailed procedures for other fast-neutron detectors are referenced in Practice E261. 1.4 This standard does not purport to address all of the...

  19. Fast neutron tomography with real-time pulse-shape discrimination in organic scintillation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Joyce, Malcolm J., E-mail: m.joyce@lancaster.ac.uk [Department of Engineering, Lancaster University, Lancaster, Lancashire LA1 4YW (United Kingdom); Agar, Stewart [Department of Engineering, Lancaster University, Lancaster, Lancashire LA1 4YW (United Kingdom); Aspinall, Michael D. [Hybrid Instruments Ltd., Gordon Manley Building, Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YW (United Kingdom); Beaumont, Jonathan S.; Colley, Edmund; Colling, Miriam; Dykes, Joseph; Kardasopoulos, Phoevos; Mitton, Katie [Department of Engineering, Lancaster University, Lancaster, Lancashire LA1 4YW (United Kingdom)

    2016-10-21

    A fast neutron tomography system based on the use of real-time pulse-shape discrimination in 7 organic liquid scintillation detectors is described. The system has been tested with a californium-252 source of dose rate 163 μSv/h at 1 m and neutron emission rate of 1.5×10{sup 7} per second into 4π and a maximum acquisition time of 2 h, to characterize two 100×100×100 mm{sup 3} concrete samples. The first of these was a solid sample and the second has a vertical, cylindrical void. The experimental data, supported by simulations with both Monte Carlo methods and MATLAB®, indicate that the presence of the internal cylindrical void, corners and inhomogeneities in the samples can be discerned. The potential for fast neutron assay of this type with the capability to probe hydrogenous features in large low-Z samples is discussed. Neutron tomography of bulk porous samples is achieved that combines effective penetration not possible with thermal neutrons in the absence of beam hardening.

  20. Pathologic changes in the hearts of beagles irradiated with fractionated fast neutrons or photons

    International Nuclear Information System (INIS)

    Zook, B.C.; Bradley, E.W.; Casarett, G.W.; Rogers, C.C.

    1981-01-01

    Thirty-nine adult male purebred beagles received either fast-neutron or photon irradiation to the right thorax to determine the effects on pulmonary tissue. The right atrium, a small portion of the right ventricle, and the right anterior abdomen were included in the field. Twenty-four dogs (six/group) received fast neutrons with a mean energy of 15 MeV to doses of 1000, 1500, 2250, or 3375 rad in four fractions per week for 6 weeks. Fifteen dogs received 3000, 4500, or 6750 rad of photons (five/group) in an identical fractionation pattern. Fourteen dogs died or were euthanatized in extremis between 47 and 708 days after radiation because of radiation damage to digestive organs. Six other dogs died of anesthetic accidents between 196 and 1144 days after radiation; these deaths were probably related to hepatic dysfunction. Two neutron-irradiated dogs developed cardiac neoplasms after 396 and 1624 days. One dog died of a myocardial infarct and one died of an unrelated infection. The major atrial lesions were hemorrhage and necrosis of myocardial cells in dogs that died 47-109 days postirradiation. Myocardial and endocardial fibrosis were most extensive in dogs that died 84 or more days following irradiation. All beagles had degenerative and occlusive vascular changes associated with atrial lesions. The relative biological effectiveness of fast neutrons for pathologic injury of the heart was estimated to be between 4 and 5

  1. An estimation of fast neutron fluence on the KMRR core wall

    International Nuclear Information System (INIS)

    Lee, Byung-Chul; Lee, Ji-Bok; Kang, Chang-Soon.

    1991-01-01

    The fast neutron fluence (E > 1 MeV) hitting the KMRR core wall of zircaloy-4 was calculated using a two-dimensional discrete ordinates transport computer code DOT4.2. For the nuclear data base, 171 neutron groups of the DLC-41C/VITAMIN-C library were collapsed into 21 groups, of which the highest 8 groups had E > 1 MeV, using an one-dimensional discrete ordinates transport computer code ANISN. To construct a three-dimensional flux, a leakage correction factor was introduced for axial leakage treatment. The leakage correction factor was obtained from ANISN cylinder and DOT(r,z) calculations. The calculated fast neutron fluence was compared with that of the three-dimensional simulation using a Monte Carlo transport computer code MCNP. Assuming a 30-yr reactor lifetime with 80% capacity factor, the maximum fast neutron fluence on the KMRR core wall is expected to be 9.80 x 10 22 n/cm 2 . (author)

  2. Application of Fast Neutron Activity for Analysing Element Content on the Air Particulate

    International Nuclear Information System (INIS)

    Elin Nuraini; Ngasifudin; Sunardi; Elisabeth

    2003-01-01

    The research on application of fast neutron activation analysis for analysing element content on the air particulate has been done. The research about analysis of the particulate matters contained in non industrial traffic territory of Surakarta and full industrial traffic territory of Karanganyar, had been done using Fast Neutron Activation Analysis Method. Fast Neutron Activation Analysis method is one of the element analysis method which it's basic principle causes radioactivity appearance from the samples after being irradiated by neutron. The qualitative analysis method is based on the measuring of specific energy which was radiated by radioactive's nucleus and quantitative analysis method is based on the measuring of the intensity of each peak gamma energy. The qualitative analysis results showed, some element were identified i.e : 51 V ; 200 Pb, 27 Al and 52 Cr. The result showed that Pb level is 2.21 ± 0.09x10 -1 mg/m 3 in non industrial traffic territory of Surakarta and 2.78 ± 0.11x10 -1 mg/m 3 full industrial traffic territory of Karanganyar, this value greater than threshold value according 6.0x10 -2 mg/m 3 . (author)

  3. Monte Carlo simulation optimisation of zinc sulphide based fast-neutron detector for radiography using a {sup 252}Cf source

    Energy Technology Data Exchange (ETDEWEB)

    Meshkian, Mohsen, E-mail: mohsenm@ethz.ch

    2016-02-01

    Neutron radiography is rapidly extending as one of the methods for non-destructive screening of materials. There are various parameters to be studied for optimising imaging screens and image quality for different fast-neutron radiography systems. Herein, a Geant4 Monte Carlo simulation is employed to evaluate the response of a fast-neutron radiography system using a {sup 252}Cf neutron source. The neutron radiography system is comprised of a moderator as the neutron-to-proton converter with suspended silver-activated zinc sulphide (ZnS(Ag)) as the phosphor material. The neutron-induced protons deposit energy in the phosphor which consequently emits scintillation light. Further, radiographs are obtained by simulating the overall radiography system including source and sample. Two different standard samples are used to evaluate the quality of the radiographs.

  4. Effects of fast neutrons on spermatogenesis of the fish, Oryzias latipes. [X radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hyodo-Taguchi, Y.; Maruyama, T.

    1977-05-01

    The weight loss of the testes, the behavior of the primary spermatogonia Ia and Ib, and the inhibition of DNA synthesis in the testes of the fish, Oryzias latipes, which had been kept at low temperature, irradiated with 2 MeV of fast neutrons (100, 200, 400, and 600 rad), and transferred to 25/sup 0/C, were investigated and compared with the effects of 200 kVp of x rays. A considerable weight loss of the testes was demonstrated at 15 days after irradiation with neutrons. The 50% effective dose (ED/sub 50/) for weight loss of testes was less than 100 rad after fast neutrons and about 500 rad after 200 kVp of x rays. Although the primary spermatogonia Ia were not significantly reduced in number after neutron irradiation, the primary spermatogonia Ib were markedly damaged. At 3 days after irradiation, the pyknoses of the primary spermatogonia Ib and surviving fraction of the cells depended on the exposure dose. Fast neutrons had ED/sub 50/ values of 330 rad at 3 days and 130 rad at 5 days after irradiation in the surviving fraction of the primary spermatogonia Ib and after x irradiation; ED/sub 50/ values were 810 and 490 rad at 3 and 5 days, respectively. In all dose groups, the lowest number of the cells was observed at 15 days. Thereafter the number of the spermatogonia Ib increased, returning to the control level and 55% of the control in the fish irradiated with 100 and 200 rad of neutrons at 30 days.

  5. Neutron flux shape effects in large fast reactor safety calculations

    International Nuclear Information System (INIS)

    Galati, A.; Loizzo, P.; Musco, A.

    1978-01-01

    Three classes of accidents in a large fast reactor were studied by the two-dimensional core dynamics code NADYP-2. A Modified version of the code, including a point kinetics module, allowed comparison between 2D and 0D power, reactivity and temperature histories. A strong shape effect was evidenced by these calculations in the boiling phase of LOF accidents as well as in the accident generated by control rod removal. Some future possibilities of by passing the consequences of this effect are indicated

  6. Detection of low caloric power of coal by pulse fast-thermal neutron analysis

    International Nuclear Information System (INIS)

    Gu De-shan; Sang Hai-feng; Qiao Shuang; Liu Yu-ren, Liu Lin-mao; Jing Shi-wei; Chinese Academy of Sciences, Changchun

    2004-01-01

    Analysis method and principle of pulse fast-thermal neutron analysis (PFTNA) are introduced. A system for the measurement of low caloric power of coal by PFTNA is also presented. The 14 MeV pulse neutron generator and BGO detector and 4096 MCA were applied in this system. A multiple linear regression method applied to the data solved the interferential problem of multiple elements. The error of low caloric power between chemical analysis and experiment was less than 0.4 MJ/kg. (author)

  7. Fast neutron activation analysis and radioisotope X-ray fluorescence study on KALEWA and NAMMA coal

    International Nuclear Information System (INIS)

    Naing-Win

    1981-07-01

    Kalewa coal was studied with Fast Neutron Activation Analysis (FNAA) technique, employing KAMAN A-710 neutron generator and HP(Ge) detector coupled to ''Canberra'' series 30 MCA. Sequential irradiation and dual aluminium foil monitoring method was employed. Simultaneous multielement analysis was carried out. Namma Coal was studied with radioisotope X-ray Fluorescence (XRF) technique, employing Co-57 exciter source and HP(Ge) detector coupled to ''Canberra'' series 40 MCA. In both FNAA and XRF study, the results obtained were compared to that obtained with Atomic Absorption Spectrophotometry (AAS) technique. Finally, the results were reviewed together with those obtained from similar work on coal with FNAA and XRF techniques. (author)

  8. Image processing and resolution restoration of fast-neutron hodoscope data

    International Nuclear Information System (INIS)

    Rhodes, E.A.; DeVolpi, A.

    1982-01-01

    The fast-neutron hodoscope is a cineradiographic device that monitors fuel motion within thick opaque test capsules during radiation transients at the Transient Reactor Test Facility reactor which simulate accident conditions in power reactors. By means of a collimator and detector array, emissive neutron radiographic digital data is collected in time-resolved and static (scan) modes. Data is digitally reconstructed into raidographic images and used directly for quantitative analysis. Spatial resolution is adequate in most cases, but is marginal for a few experiments. Collimator repositioning, scan increment size-reduction, and deconvolution algorithms are being applied to improve resolution of existing collimators

  9. Direct interaction of fast neutrons with β and γ vibrational band levels of tungsten even isotopes

    International Nuclear Information System (INIS)

    Delaroche, J.P.

    1982-09-01

    As an extension of a previous report on fast neutron scattering from the first and second excited states of 182 W, 184 W, 186 W, we have investigated the question of the importance of direct interaction of neutrons with β- and γ-band levels of these nuclei. For that purpose we have performed new coupled channel calculations using extended coupling bases and collective functions from the Rotation-Vibration and Kumar and Baranger Models. The predictions are compared with recent scattering data obtained at incident energies below 4 MeV [fr

  10. Inhomogeneous strain induced by fast neutron irradiation in NaKSO4 crystals

    International Nuclear Information System (INIS)

    Kandil, S.H.; El Gamal, M.A.; El Khatib, A.; El Wahidy, E.F.

    1987-06-01

    The effect of fast neutron irradiation on the thermal properties of NaKSO 4 crystals was studied around the phase transition temperature T c =453 K. The thermal expansion coefficient as well as the phase transition temperature were found to be dependent upon the irradiation dose. The specific heat, C p , showed multiple peaks in the phase transition temperature region. An explanation of this behaviour was based on the induced inhomogeneous strain in the crystal casued by the neutron irradiation process. (author). 10 refs, 3 figs

  11. Contribution of direct processes to cross sections of fast neutron scattering by copper nuclei

    CERN Document Server

    Korzh, Y O

    2002-01-01

    Adaptability of the optical-statistical approach, based on the spherical optical model, excited core model, and modern versions of the statistical model, for description of the experimental data on neutron total and scattering cross sections for sup 6 sup 3 sup , sup 6 sup 5 Cu and Cu nuclei in the 0.5-15 MeV energy range is studied. It is shown that these experimental data can be adequately described in this approach by using the individual set of optical potential parameters only. The results of theoretical analysis are used for study of fast neutron interaction mechanism with the nuclei under consideration.

  12. The determination of fast neutron fluence in radiation stability tests of steel samples

    International Nuclear Information System (INIS)

    Hogel, J.; Vespalec, R.

    1979-01-01

    The activation method is described of determining fast neutron fluence. Samples of steel designed for WWER type reactor pressure vessels were irradiated in the CHOUCA-rigs in the core of the WWR-S reactor. The neutron spectrum was measured by the multiple activation foil method and the effective cross sections of fluence monitors were calculated. The fluences obtained from the reactions 54 Fe(n,p) 54 Mn and 63 Cu(n,α) 60 Co are presented and the method is discussed. (author)

  13. Preliminary studies leading to a conceptual design of a 1000 MWe fast neutron reactor

    International Nuclear Information System (INIS)

    Vendryes, G.; Zaleski, C.P.

    1964-01-01

    This report presents the results of studies which seemed important to undertake in connexion with the development of fast neutron reactors. - It points out the advantage of high internal breeding ratios (∼1, 1) which are necessary in order to get a small change in time both in power distribution and reactivity (less: than 0.005 Δk/k in 18 months). - It shows how to achieve this goal, when simultaneously power distribution flattening is obtained. These results in a higher mean specific power (which is an economic gain) and therefore in a smaller doubling time (about 10 years). - It attempts to find criteria concerning the specific power that should be used in future reactor designs -It presents a conceptional design of a 1000 MWe fast neutron reactor, for the realisation of which no technological impossibility appears. - It shows that the dynamic behaviour seems satisfactory despite a positive total isothermal sodium coefficient. - It tries to predict the development of fast reactors within the future total nuclear program. It does not appear that fissile materials supply problems should in France slow down the development of fast neutron reactors, which will be essentially tied up to its economical ability to produce cheap electric power. (authors) [fr

  14. Scintillation spectrometer system for measuring fast-neutron spectra in beam geometry

    International Nuclear Information System (INIS)

    Simons, G.G.; Larson, J.M.; Reynolds, R.S.

    1977-05-01

    A high-energy liquid-organic scintillation spectrometer system is described. This spectrometer was developed to measure neutron spectra in extracted beams from zero-power fast reactors. The highly efficient NE-213 scintillation solution was used as the neutron detection medium. Identification and removal of gamma-ray-induced events was accomplished using electronic pulse shape discrimination. Instrumentation used to process the discrete pulses stemming from neutron and gamma-ray interactions, within the scintillation solution, is described in detail. Evaluation of the system's performance is discussed for a gamma-ray discrimination ratio of nominally 1000:1, a total countrate of 3000 cps, and a dynamic range corresponding to neutron energies from 1 to 10 MeV. Operation above 10 MeV is certainly possible. However, since the neutron flux above 10 MeV was negligible in the radiation fields of interest in this work, the operating characteristics of the spectrometer were not evaluated above 10 MeV. Neutron spectra are reported for extracted beam measurements made on ZPPR assembly 4, phase 2

  15. Chemical Engineering Division fast-neutron dosimetry annual report, July 1975--June 1976

    Energy Technology Data Exchange (ETDEWEB)

    Heinrich, R R; Greenwood, L R; Kennerley, R J; Chellew, N R; Popek, R J; Malewicki, R L; Cafasso, F A; Burris, L

    1976-01-01

    One of the objectives of the Dosimetry and Damage Analysis Center is to provide standardized dosimetry technology for materials-study programs within the ERDA Division of Magnetic Fusion Energy. Current efforts have included characterization of neutron environments in terms of fluence and spectral distribution for materials experiments conducted at the Lawrence Livermore Laboratory's (LLL) Rotating Target Neutron Source and at the LLL-Davis Cyclograaff. Environment characterization efforts at Brookhaven National Laboratory's High Flux Beam Reactor and those pertaining to an enriched-uranium converter for the ANL CP-5 reactor are also described. The capability of calculating material radiation damage parameters associated with these neutron environments is demonstrated. Average fission yields determined from two fast-neutron irradiations and one thermal-neutron irradiation are compiled for laboratories participating in the interlaboratory Reaction Rate program. These results are in excellent agreement with literature values. Progress on the development of /sup 10/B- and /sup 6/Li-loaded liquid scintillation detectors for detecting very low intensity neutrons is presented. Material purification tests and performance tests of scintillation mixtures are described.

  16. Experimental study on fast neutron streaming through grid-plate shield of a LMFBR

    International Nuclear Information System (INIS)

    Oka, Yoshiaki; Wakabayashi, Hiroaki; An, Shigehiro; Suzuki, Ikunori.

    1976-01-01

    Neutron streaming through the holes penetrating the grid plate shield of a prototype LMFBR was experimentally examined. The mockups of the grid plate shield were made of iron and aluminum. Experiments were conducted at the vertical column of ''YAYOI'', the fast neutron source reactor of University of Tokyo. A He-3 spectrometer was employed in order to measure the transmitted neutron spectrum, while rhodium and indium threshold foils were for the integral flux above specific energies and their spatial distributions in the form of reaction rates. The streaming factor for usual small bended holes is 1.28+-0.04 as to the integral neutron flux above 0.1 MeV and 1.30+-0.12 as to the reaction rate of indium foil. Use were made of the one and two dimensional neutron transport code ANISN and TWOTRAN for evaluation by computation. The reaction rates calculated by infinite slab model with ANISN code agree well with the experiments when normalized at the source point where neutrons are incident on the grid plate shield. (auth.)

  17. Detection of fast neutrons with LiF and Al{sub 2}O{sub 3} scintillating bolometers

    Energy Technology Data Exchange (ETDEWEB)

    Coron, N; Gironnet, J; Leblanc, J; Marcillac, P de; Redon, T; Torres, L [Institut d' Astrophysique Spatiale, Bat 121, 91405 Orsay, Paris (France); Cuesta, C; Domange, J; Garcia, E; Martinez, M; Ortigoza, Y; Ortiz de Solorzano, A; Pobes, C; Puimedon, J; Rolon, T; Sarsa, M L; Villar, J A, E-mail: puimedon@unizar.e [Laboratorio de Fisica Nuclear y Astroparticulas, Universidad de Zaragoza, 50009 Zaragoza (Spain)

    2010-01-01

    Scintillating bolometers of LiF and Al{sub 2}O{sub 3} can monitor the fast neutrons flux in WIMPs searches. With both materials we merge the traditional fast neutron detection methods of induced reactions and scattering. The ROSEBUD collaboration devoted an underground run in the old Canfranc laboratory to study the response of LiF and Al{sub 2}O{sub 3} to fast neutrons from {sup 252}Cf. Both bolometers were used simultaneously in a common experimental set-up resembling those of current WIMPs searches, which could give valuable insights into future WIMPs searches with cryogenic detectors as EURECA.

  18. Comparison between Silicon-Carbide and diamond for fast neutron detection at room temperature

    Science.gov (United States)

    Obraztsova, O.; Ottaviani, L.; Klix, A.; Döring, T.; Palais, O.; Lyoussi, A.

    2018-01-01

    Neutron radiation detector for nuclear reactor applications plays an important role in getting information about the actual neutron yield and reactor environment. Such detector must be able to operate at high temperature (up to 600° C) and high neutron flux levels. It is worth nothing that a detector for industrial environment applications must have fast and stable response over considerable long period of use as well as high energy resolution. Silicon Carbide is one of the most attractive materials for neutron detection. Thanks to its outstanding properties, such as high displacement threshold energy (20-35 eV), wide band gap energy (3.27 eV) and high thermal conductivity (4.9 W/cm·K), SiC can operate in harsh environment (high temperature, high pressure and high radiation level) without additional cooling system. Our previous analyses reveal that SiC detectors, under irradiation and at elevated temperature, respond to neutrons showing consistent counting rates as function of external reverse bias voltages and radiation intensity. The counting-rate of the thermal neutron-induced peak increases with the area of the detector, and appears to be linear with respect to the reactor power. Diamond is another semi-conductor considered as one of most promising materials for radiation detection. Diamond possesses several advantages in comparison to other semiconductors such as a wider band gap (5.5 eV), higher threshold displacement energy (40-50 eV) and thermal conductivity (22 W/cm·K), which leads to low leakage current values and make it more radiation resistant that its competitors. A comparison is proposed between these two semiconductors for the ability and efficiency to detect fast neutrons. For this purpose the deuterium-tritium neutron generator of Technical University of Dresden with 14 MeV neutron output of 1010 n·s-1 is used. In the present work, we interpret the first measurements and results with both 4H-SiC and chemical vapor deposition (CVD) diamond

  19. Comparison between Silicon-Carbide and diamond for fast neutron detection at room temperature

    Directory of Open Access Journals (Sweden)

    Obraztsova O.

    2018-01-01

    Full Text Available Neutron radiation detector for nuclear reactor applications plays an important role in getting information about the actual neutron yield and reactor environment. Such detector must be able to operate at high temperature (up to 600° C and high neutron flux levels. It is worth nothing that a detector for industrial environment applications must have fast and stable response over considerable long period of use as well as high energy resolution. Silicon Carbide is one of the most attractive materials for neutron detection. Thanks to its outstanding properties, such as high displacement threshold energy (20-35 eV, wide band gap energy (3.27 eV and high thermal conductivity (4.9 W/cm·K, SiC can operate in harsh environment (high temperature, high pressure and high radiation level without additional cooling system. Our previous analyses reveal that SiC detectors, under irradiation and at elevated temperature, respond to neutrons showing consistent counting rates as function of external reverse bias voltages and radiation intensity. The counting-rate of the thermal neutron-induced peak increases with the area of the detector, and appears to be linear with respect to the reactor power. Diamond is another semi-conductor considered as one of most promising materials for radiation detection. Diamond possesses several advantages in comparison to other semiconductors such as a wider band gap (5.5 eV, higher threshold displacement energy (40-50 eV and thermal conductivity (22 W/cm·K, which leads to low leakage current values and make it more radiation resistant that its competitors. A comparison is proposed between these two semiconductors for the ability and efficiency to detect fast neutrons. For this purpose the deuterium-tritium neutron generator of Technical University of Dresden with 14 MeV neutron output of 1010 n·s-1 is used. In the present work, we interpret the first measurements and results with both 4H-SiC and chemical vapor deposition (CVD

  20. Fast neutron spectrometry by bolometers lithium target for the reduction of background experiences of direct detection of dark matter

    International Nuclear Information System (INIS)

    Gironnet, J.

    2010-01-01

    Fast neutron spectrometry is a common interest for both direct dark matter detection and for nuclear research centres. Fast neutrons are usually detected indirectly. Neutrons are first slowed down by moderating materials for being detected in low energy range. Nevertheless, these detection techniques are and are limited in energy resolution. A new kind of fast neutron spectroscopy has been developed at the Institut d'Astrophysique Spatiale (IAS) in the aim of having a better knowledge of neutron backgrounds by the association of the bolometric technique with neutron sensitive crystals containing Li. Lithium-6 is indeed an element which has one the highest cross section for neutron capture with the 6 Li(n,α) 3 H reaction. This reaction releases 4,78 MeV tagging energetically each neutron capture. In particular for fast neutrons, the total energy measured by the bolometer would be the sum of this energy reaction and of the incoming fast neutron energy. To validate this principle, a spectrometer for fast neutrons, compact and semi-transportable, was built in IAS. This cryogenic detector, operated at 300 - 400 mK, consists of a 0.5 g LiF 95% 6 Li enriched crystal read out by a NTD-Ge sensor. This PhD thesis was on the study of the spectrometer characteristics, from the first measurements at IAS, to the measurements in the nuclear research centre of the Paul Scherrer Institute (PSI) until the final calibration with the Amande instrument of the Institut de Radioprotection et de Surete Nucleaire (IRSN). (author)

  1. Improvements in fast-neutron spectroscopy methods (1961); Amelioration des methodes de spectrometrie des neutrons rapides (1961)

    Energy Technology Data Exchange (ETDEWEB)

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

    1961-02-15

    This research aimed at improving fast-neutron electronic detectors based on n-p elastic scattering. The first part concerns proportional counters; careful constructional methods have made it possible to plot mono-energetic neutron spectra in the range 700 keV - 3 MeV with a resolution of 7 per cent. The second part concerns scintillation counters: an organic scintillator and an inorganic scintillator covered with a thin layer of a scattering agent. An exact study of the types of scintillation has made it possible to develop efficient discriminator circuits. Different neutron spectra plotted in the presence of a strong gamma background are presented. The last part deals with the development of form discrimination methods for the study, in the actual beam, of the elastic scattering of 14.58 MeV electrons. With hydrogen, the distribution f ({phi}) of the recoil protons is f({phi}) = 1 + 0.034 cos {phi} + 0.042 cos{sup 2} {phi}. With tritium the scattering is strongly anisotropic; the curve representing the variation of the differential cross-section for the elastic scattering in the centre of mass system is obtained with a target containing 1 cm{sup 3} of tritium. (author) [French] Le travail a porte sur l'amelioration des detecteurs electroniques de neutrons rapides bases sur la diffusion elastique n-p. La premiere partie est relative aux compteurs proportionnels; des methodes soignees de fabrication ont permis des traces de spectres de neutrons monoenergetiques dans le domaine 700 keV - 3 MeV avec une resolution de 7 pour cent. La deuxieme partie est relative au compteur a scintillations; scintillateur organique et scintillateur mineral recouvert d'un diffuseur mince. Une etude precise des formes de scintillations a permis la mise au point de circuits discriminateurs efficaces. Differents spectres de neutrons traces en presence d'un fond gamma intense sont presentes. La derniere partie est relative a la mise en oeuvre des methodes de discrimination de

  2. Fast neutron radiography and tomography of wood as compared to photon based technologies

    International Nuclear Information System (INIS)

    Osterloh, K.R.S.; Radel, Ch.; Zscherpel, U.; Meinel, D.; Weidemann, G.; Goebbels, J.; Ewert, U.; Bucherl, Th.; Hasenstab, A.

    2007-01-01

    It is a well known fact that neutron radiation has absorption properties complementary to photons. While dense materials are capable to absorbing both, X- and gamma rays, they are apparently transparent to neutrons. Vice verse, organic materials containing large amounts of hydrogen are well penetrated by photons, but not by neutrons. This property of being easily absorbed by light elements such as hydrogen makes them predestined to imaging e.g. the distribution of water within a specimen. The content of moisture is of concern in wood, particularly in lumber or in girders, since this could make them prone to rot. If wet and dry wood differs in its overall content of hydrogen rather than in its matrix of hydrocarbons, then this should result in an observable contrast in neutron radiographs. Usually, best radiographic results are obtainable with thermal neutrons. However, since wood by itself constitutes a hydrogen containing material, it absorbs them considerably from a certain thickness on; i.e, they would hardly penetrate e.g. a girder. This study demonstrates that it is feasible to use fast neutrons with a more efficient penetration capability for this purpose. Digital imaging technologies are essential for radiographs of wooden specimens since structural details appear rather faintly in the original images requiring some processing to display them clearly. Particularly large samples like trunks or girders leave poor signal to noise ratios. The noise has been compensated successfully by dedicated filtering. In addition, neutron radiographs are blotched with white spots caused by unavoidable ubiquitous radiation while the beam is open. Specially developed algorithms have been applied to remove selectively these flaws within the image while leaving other fine structures untouched, i.e. avoiding the loss of filigree like features by smoothing. Samples will be shown subjected both to neutron and X-ray radiography, and tomography as well. The differences between the

  3. A review of the scientific basis for the quality factor for fast neutrons

    International Nuclear Information System (INIS)

    Myers, D.K.; Johnson, J.R.

    1986-04-01

    Recently, the ICRP has recommended that the quality factor for fast neutrons be increased by a factor of two. They did not give a detailed explanation of the reasons for their recommendations, but indicated that the reasons would be developed as part of a much larger review of the quality factor for all radiations. Since it is AECB's policy to follow ICRP's recommendations unless there is good reason not to do so, and since the changing of the quality factor for neutrons has not been generally accepted by other countries a review of the scientific basis for the neutron quality factor was requested. This report gives results of that review. The report reviews the available published information on the relative biological effectiveness (RBE) of neutrons and on the physical basis for the neutron quality factor for use in personnel dosimetry programs. It is concluded that some, but by no means all, of the RBE data supports an increased quality factor, but the relevance of this data to the quality factor for use in radiaton protection is not clear for two reasons. Firstly, the biological endpoints are not all directly extrapolatable to late stochastic effects in humans, and secondly, the current conservative selection of a quality factor for neutrons, and the conservative practise of equating whole body dose to the maximum dose equivalent, leads to a factor of about 10 conservatism in the assignment of neutron dose equivalents. The overall conclusion of the review is that there is no compelling reason to increase the quality factor for neutrons at least until the ICRP has completed its comprehensive review of the subject. 58 refs

  4. Monte Carlo simulation of fast neutron scattering experiments including DD-breakup neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, D.; Siebert, B.R.L.

    1993-06-01

    The computational simulation of the deuteron breakup in a scattering experiment has been investigated. Experimental breakup spectra measured at 16 deuteron energies and at 7 angles for each energy served as the data base. Analysis of these input data and of the conditions of the scattering experiment made it possible to reduce the input data. The use of one weighted breakup spectrum is sufficient to simulate the scattering spectra at one incident neutron energy. A number of tests were carried out to prove the validity of this result. The simulation of neutron scattering on carbon, including the breakup, was compared with measured spectra. Differences between calculated and measured spectra were for the most part within the experimental uncertainties. Certain significant deviations can be attributed to erroneous scattering cross sections taken from an evaluation and used in the simulation. Scattering on higher-lying states in [sup 12]C can be analyzed by subtracting the simulated breakup-scattering from the experimental spectra. (orig.)

  5. Monte Carlo simulation of fast neutron scattering experiments including DD-breakup neutrons

    International Nuclear Information System (INIS)

    Schmidt, D.; Siebert, B.R.L.

    1993-06-01

    The computational simulation of the deuteron breakup in a scattering experiment has been investigated. Experimental breakup spectra measured at 16 deuteron energies and at 7 angles for each energy served as the data base. Analysis of these input data and of the conditions of the scattering experiment made it possible to reduce the input data. The use of one weighted breakup spectrum is sufficient to simulate the scattering spectra at one incident neutron energy. A number of tests were carried out to prove the validity of this result. The simulation of neutron scattering on carbon, including the breakup, was compared with measured spectra. Differences between calculated and measured spectra were for the most part within the experimental uncertainties. Certain significant deviations can be attributed to erroneous scattering cross sections taken from an evaluation and used in the simulation. Scattering on higher-lying states in 12 C can be analyzed by subtracting the simulated breakup-scattering from the experimental spectra. (orig.)

  6. Present status of fast neutron therapy survey of the clinical data and of the clinical research programmes

    International Nuclear Information System (INIS)

    Wambersie, A.; Richard, F.

    1989-01-01

    The clinical results reported from the different neutron therapy centres, in USA, Europe and Asia, are reviewed. Fast neutrons were proven to be superior to photons for locally extended inoperable salivary gland tumours. The reported overall local control rates are 67% and 24% respectively. Paranasal sinuses and some tumours of the head and neck area, especially extended tumours with large fixed lymph nodes, are also indications for neutrons. By contrast, the results obtained for brain tumours were, in general, disappointing. Neutrons were shown to bring a benefit in the treatment of well differentiated slowly growing soft tissue sarcomas. The reported overall local control rates were 53% and 38% after neutron and photon irradiation respectively. Better results, after neutron irradiation, were also reported for bone- and chondrosarcomas. The reported local control rates are 54% for osteosarcomas and 49% for chondrosarcomas after neutron irradiation; the corresponding values are 21% and 33% respectively after photon irradiation. For locally extended prostatic adenocarcinoma, the superiority of mixed schedule (neutrons + photons) was demonstrated by a RTOG randomized trial (local control rates 77% for mixed schedule compared to 31% for photons). Neutrons were also shown to be useful for palliative treatment of melanomas. Further studies are needed in order to definitively evaluate the benefit of fast neutrons for other localisations such as uterine cervix, bladder, and rectum. It can be concluded that fast neutrons are superior to photons for at least 10% to 20% of the radiotherapy patients. As far as the technical point of view is concerned, it is recognized that the first patient series were treated in ''suboptimal'' conditions. However, recently, important improvements were made. In particular, several high-energy hospital-based cyclotrons are now fully dedicated to neutron therapy. It is likely that these improved technical conditions will further extend the

  7. Fast neutron spectroscopy by gas proton-recoil methods at the light water reactor pressure vessel simulator

    International Nuclear Information System (INIS)

    Rogers, J.W.

    1980-10-01

    Fast neutron spectrum measurements were made in a Light Water Reactor (LWR) Pressure Vessel Simulator (PVS) to provide neutron spectral definition required to appropriately perform and interpret neutron dosimetry measurements related to fast neutron damage in LWR-PV steels. Proton-recoil proportional counter methods using hydrogen and methane gas-filled detectors were applied to obtain the proton spectra from which the neutron spectra were derived. Cylindrical and spherical geometry detectors were used to cover the neutron energy range between 50 keV and 2 MeV. Results show that the neutron spectra shift in energy distribution toward lower energy between the front and back of a PVS. The relative neutron flux densities increase in this energy range with increasing thickness of the steel. Neutron spectrum fine structure shapes and changes are observed. These results should assist in the generation of more accurate effective cross sections and fluences for use in LWR-PV fast neutron dosimetry and materials damage analyses

  8. Studies on the response of 3He and 4He proportional counters to monoenergetic fast neutrons

    International Nuclear Information System (INIS)

    Manolopoulou, M.; Fragopoulou, M.; Stoulos, S.; Koukorava, C.; Spyrou, A.; Perdikakis, G.; Hashemi-Nezhad, S.R.; Zamani, M.

    2006-01-01

    Two helium filled proportional counters ( 3 He and 4 He) were studied to establish the optimum operating conditions when these counters are used for fast neutron measurements, as well as to examine the linearity of the pulse height with neutron energy. The detectors were irradiated with mono-energetic neutrons in the energy range of 230 keV-22 MeV, produced via 7 Li(n,p) 7 Be, 2 H(d,n) 3 He and 3 H(d,n) 4 He reactions in a Tandem Van de Graff accelerator. The gamma ray contribution to the obtained pulse height distribution and the resolution of the counters as a function of shaping time constant and applied high voltage were studied

  9. Moessbauer effect on a reactor pressure vessel irradiated with fast neutrons

    International Nuclear Information System (INIS)

    Yi, Y. G.; Kim, H. S.; Hong, C. Y.; Jang, K. S.; Yoo, Y. B.

    1998-01-01

    To estimate the integrity of a nuclear-reactor pressure vessel (RPV) subjected to neutron irradiation, we studied the changes in the material properties of RPV steel irradiated by fast neutrons (E n > 1 MeV) at a level of 0 ∼ 10 18 n/cm 2 . An X-ray diffraction experiment was done to investigate the changes in the phases of all specimens, nd the influence of the neutron irradiation on the RPV steel studied by the Mossbauer effect. The absorption area decreased rapidly for doses above 10 17 n/cm 2 , but at site 3 the value of the isomer shift and the quadrupole splitting increased. The magnetic hyperfine field at site 1 and 2 varied only within ±3 %

  10. Standard Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of Aluminum

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This test method covers procedures measuring reaction rates by the activation reaction 27Al(n,α)24Na. 1.2 This activation reaction is useful for measuring neutrons with energies above approximately 6.5 MeV and for irradiation times up to about 2 days (for longer irradiations, see Practice E261). 1.3 With suitable techniques, fission-neutron fluence rates above 106 cm−2·s−1 can be determined. 1.4 Detailed procedures for other fast neutron detectors are referenced in Practice E261. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  11. Study of the reflection of fast neutrons by a simple theory of shock. Application to iron

    International Nuclear Information System (INIS)

    Devillers, Christian; Hasselin, Gilbert

    1964-10-01

    By using a first shock theory, the authors report the calculation of an albedo current for fast neutrons, i.e. the rate between the reflected current per cm 2 of plate and the incident current on the same cm 2 . They also compute the spectrum and the angular distribution of reflected neutrons. These calculations are performed by means of three specific software: Psyche 1 for the determination of the albedo due to elastic scattering, and Psyche 2 and 3 for inelastic scattering (the first one addresses incident neutrons with an energy 0.86 and 5 MeV, and the second one the 5-12 MeV energy band). Hypotheses for each calculation are presented, as well as calculation principles and methods. Results are briefly presented and discussed in terms of albedo evolution with respect to incidence and to plate thickness

  12. Radiative capture of fast neutrons in 165Ho and 181Ta

    International Nuclear Information System (INIS)

    Poenitz, W.P.

    1975-06-01

    The fast neutron capture cross sections of 165 Ho and 181 Ta were measured from 0.3 to 3.0 MeV. A 1300 l large liquid scintillator with a time-resolution of 3-4 nsec was used for the detection of capture events. The time-of-flight technique was utilized for background suppression. A Grey Neutron Detector was used as a neutron flux monitor. The data were normalized at 500 keV to the standard capture cross section of gold. The resulting cross sections had an uncertainty of about 7 percent. The present capture cross sections and activation cross sections reported in the literature were interpreted in terms of the statistical model, using the Hauser-Feshback formalism and the gamma-cascade model. (6 figures, 2 tables) (auth)

  13. Measurement of small-angle elastic scattering cross sections of fast neutron

    International Nuclear Information System (INIS)

    Wan Dairong; Dai Yunsheng; Liang Xuecai; Cao Jianhua

    1993-11-01

    A position-sensitive detector has been developed for studying small angle scattering of fast neutrons. The detector mainly consists of two photomultiplier tubes to monitor the liquid scintillator. The time difference between two signals from two photomultiplier tubes is used to determine the position of light emitted. The 14.7 MeV neutron elastic scattering differential cross section of Zr, Nb, Ti and Pb were measured by position-sensitive detector and associated particle time-of-flight method at the angles from 3 deg to 15 deg. The corrections for neutron fluence attenuation, multiple scattering and finite geometry are performed by using Monte-Carlo method. The experimental results provide data needed in nuclear engineering design

  14. Radial plasma profile and neutron yield in an adiabatic trap with fast atom injection

    International Nuclear Information System (INIS)

    Panov, D.A.

    1988-01-01

    Radial profiles of ion densities depending on two dimensionless parameters, which values are determined by the trap, plasma and injected beam parameters are found in dimensionless units for a plasma generated by fast atom injection in an adiabatic trap. The calculated profiles are used for determining the neutron yield. Simple approximated dimensional relations permitting to estimate quickly neutron yield, required injection power, flux of charge exchange atoms on the wall around the plasma in a wide energy range of injected atoms, trap field modulud, injection angle, trap radius and length are determined. The energetic efficiency of neutron production is estimated and it is shown that it grows with the injection energy. 7 refs.; 7 figs

  15. Study of proton-induced reactions and correlation with fast-neutron scattering

    International Nuclear Information System (INIS)

    Hansen, L.F.

    1982-01-01

    The generation of cross sections for fast neutron-nucleon interactions obtained from elastic and charge-exchange proton data is discussed in terms of the Lane model formalism. A general description of the interaction of nucleons with nuclei is presented in terms of the optical model and the extended (or coupled-channel) optical model, together with the relation of these models to microscopic calculations of the nucleon-nucleon interaction. Comparisons between neutron elastic data and calculations carried out with optical model potentials obtained from (p,p) and (p,n) data are presented for a large number of nuclei. The validity of the Lane model and the importance of coupled effects in the actinide region are shown in a detailed comparison of calculations for elastic and inelastic neutron differential cross sections and measurements for 232 Th and 238 U

  16. Determination of phosphorus in kiwicha using analysis for activation with fast neutrons

    International Nuclear Information System (INIS)

    Bejarano P, R.

    1990-01-01

    In this study it has been used the technique of activation analysis with fast neutrons for nondestructive of Phosphorus in Kiwicha (amaranthus caudatus l.), as an alternative to the conventionally used technique of spectrophotometry. The samples are irradiated during five minutes in the IPEN's neutron generator under a fast flow of around 10 9 n/cm 2 .s after 30 seconds of the irradiation end, and are counted for 10 minutes in a NaI(Tl) detector type well jointed to a multichannel analyzer. The testing of method exactness was carried out analyzing the IAEA's H5 and H8 reference materials, obtaining a good correspondence with the certified values. The reproducibility of the method was carried out analyzing by repetition a pure standard sample of phosphorus. In the analysis of 8 samples of kiwicha it was found that the phosphorus content is in the rank of 0.3% to 0.5%. (author). 31 refs., 12 tabs., 19 figs

  17. Structure and Spatial Distribution of Ge Nanocrystals Subjected to Fast Neutron Irradiation

    Directory of Open Access Journals (Sweden)

    Alexander N. Ionov

    2011-07-01

    Full Text Available The influence of fast neutron irradiation on the structure and spatial distribution of Ge nanocrystals (NC embedded in an amorphous SiO2 matrix has been studied. The investigation was conducted by means of laser Raman Scattering (RS, High Resolution Transmission Electron Microscopy (HR-TEM and X-ray photoelectron spectroscopy (XPS. The irradiation of Ge- NC samples by a high dose of fast neutrons lead to a partial destruction of the nanocrystals. Full reconstruction of crystallinity was achieved after annealing the radiation damage at 8000C, which resulted in full restoration of the RS spectrum. HR-TEM images show, however, that the spatial distributions of Ge-NC changed as a result of irradiation and annealing. A sharp decrease in NC distribution towards the SiO2 surface has been observed. This was accompanied by XPS detection of Ge oxides and elemental Ge within both the surface and subsurface region.

  18. Effect of Fast Neutron Irradiation on Current Transport Properties of HTS Materials

    CERN Document Server

    Ballarino, A; Kruglov, V S; Latushkin, S T; Lubimov, A N; Ryazanov, A I; Shavkin, S V; Taylor, T M; Volkov, P V

    2004-01-01

    The effect of fast neutron irradiation with energy up to 35 MeV and integrated fluence of up to 5 x 10**15 cm-2 on the current transport properties of HTS materials Bi-2212 and Bi-2223 has been studied, both at liquid nitrogen and at room temperatures. The samples irradiated were selected after verification of the stability of their superconducting properties after temperature cycling in the range of 77 K - 293 K. It has been found that the irradiation by fast neutrons up to the above dose does not produce a significant degradation of critical current. The effect of room temperature annealing on the recovery of transport properties of the irradiated samples is also reported, as is a preliminary microstructure investigation of the effect of irradiation on the soldered contacts.

  19. Neutronic modeling for a Gas-cooled Fast Reactor assuming coated fuel particles

    International Nuclear Information System (INIS)

    Golfier, H.; Buiron, C.; Poinot, B.; Pothet, J. F.; Salavy, E.; Studer

    2004-01-01

    The modeling of gas cooled fast reactor (GCFR) with the SAPHYR system and in particular APOLLO2 code assuming coated fuel particles, was investigated. It aims to estimate the APOLLO2 code accuracy, solving the neutron transport equation in range of fast neutron reactors. A two level PIJ/SN APOLLO2 scheme is proposed in which the first level is devoted to the self-shielding and the leakage calculation on a cell configuration. The efficiency of a new treatment of adsorption and scattering rates in the self-shielding module of the multigroup transport code APOLLO2 has been evaluated. The results show that two-level scheme provides promising results with 172-group cross section libraries, which confirm the APOLLO2 scheme as a tool for reactor designs. (authors)

  20. The effect of gamma and fast neutron irradiations on M1 seedling growth in soybean

    International Nuclear Information System (INIS)

    Hassan, S.; Mohammad, T.; Khan, S.

    1985-01-01

    Seeds of three varieties of soybean, i.e. Bragg, Hodgson and Lee-74, having a moisture content of 11-13% were irradiated with doses of gamma, 100,200,300,400 and 500 Gray and fast neutron, 5,10,20,25 and 30 Gray, to study the effect on M1 seedling growth. The parameters studied were germination, seedling height and epicotyl length. Growth inhibition was found to increase with increasing radiation doses and the effect on germination was observed only at higher doses. Among early assessable M1 parameters for radio-sensitivity, epicotyl length has proved to be most sensitive, and hence most useful. The Relative Biological Effectiveness (RBE) values for the three varieties differed slightly for epicotyl length and the difference was more pronounced for seedling height. A dose range of 150-300 Gray of gamma rays and 10-15 Gray of fast neutron might prove useful for efficient induced mutation. (authors)

  1. The Effect of Radiator on CR-39 Registration of Fast Neutrons

    International Nuclear Information System (INIS)

    El-Badrya, B.A.; Hegazya, T.M.; Morsya, A.A.; Zaki, M.F.

    2008-01-01

    Three different configurations of a personal neutron dosimeter using CR-39 plastic detector were placed in Plastiplast pouch composed from inside to outside of Aluminum ( 27 Al, 40 Ξ m), polyethylene (PE, 20 Ξ m), Cellulose Nitrate (CN, 40 Ξ m). One dosimeter was composed of a CR-39 detector and a PE radiator (1 mm thick), another of two CR-39 detectors with one serving as radiator, and the other of CR-39 alone (without radiator). These dosimeters have been irradiated with fast neutrons of average energy 4.5 MeV with neutron fluence ranging from 5.5 x 10 6 to 0.5 x 10 8 cm - 2 emitted from 241 Am-Be neutron source. The polymeric materials have been chosen on the basis of their hydrogen contents, which are as followed: CR-39, 48%, Polyethylene, 66.7% and CN, 32% by atomic ratio to produce protons via (n, p) elastic scattering with hydrogen and increasing the detection efficiency of CR-39. After irradiation, the dose equivalent response of the detectors has been studied by using conventional etching for two periods, 6h and 8h for these configurations. The thicknesses and compositions of the radiators are chosen so as to suppress the CR-39 response below 4 MeV by preventing the recoils of hydrogen nuclei, out of the hydrogen-rich radiators (PE, CR-39), from reaching the post-etch surface of the detector. Track counting was performed using an automated system. It was found that the dosemeter responses were linear as a function of a neutron equivalent dose and that the CR-39 detector has the same response with radiator or without radiator and thus appears as a promising fast neutron dosimeter. The results are discussed and compared with the literature

  2. Characterisation of CVD diamond detectors used for fast neutron flux monitoring

    CERN Document Server

    Foulon, F; Amosov, V N; Kaschuck, Y; Frunze, V; Tromson, D; Brambilla, A

    2002-01-01

    Natural diamond detectors (NDD) have been successfully used for fast neutron spectrometry on various fusion installations in plasma diagnostics. These detectors can work at high temperature, are radiation hard and exhibit a high energy resolution. However, the use of NDD is limited by the availability of IIa type diamonds exhibiting high electronic properties. With the recent advance in the growth of high quality chemically vapour deposited (CVD) diamond at LETI, CVD diamond appears to be a very promising material for plasma diagnostics. We present here for the first time results of the use of CVD diamond detectors for fast neutron flux monitoring on a neutron generator. The characteristics of CVD diamond detectors are compared with that of high quality NDD made by TRINITI. Pulse height spectra have been measured with CVD detectors and NDD under both 5.5 MeV alpha particles and 14.1 MeV neutrons. The quality of CVD diamond enables the recording of structured spectra allowing the distinction between the differ...

  3. Fast neutrons: Inexpensive and reliable tool to investigate high-LET particle radiobiology

    International Nuclear Information System (INIS)

    Gueulette, J.; Slabbert, J.P.; Bischoff, P.; Denis, J.M.; Wambersie, A.; Jones, D.

    2010-01-01

    Radiation therapy with carbon ions as well as missions into outer space have boosted the interest for high-LET particle radiobiology. Optimization of treatments in accordance with technical developments, as well as the radioprotection of cosmonauts during long missions require that research in these domains continue. Therefore suitable radiation fields are needed. Fast neutrons and carbon ions exhibit comparable LET values and similar radiobiological properties. Consequently, the findings obtained with each radiation quality could be shared to benefit knowledge in all concerned domains. The p(66+Be) neutron therapy facilities of iThemba LABS (South Africa) and the p(65)+Be neutron facility of Louvain-la-Neuve (Belgium) are in constant use to do radiobiological research for clinical applications with fast neutrons. These beams - which comply with all physical and technical requirements for clinical applications - are now fully reliable, easy to use and frequently accessible for radiobiological investigations. These facilities thus provide unique opportunities to undertake radiobiological experimentation, especially for investigations that require long irradiation times and/or fractionated treatments.

  4. High Hydrogen Content Graphene Hydride Compounds & High Cross-Section Cladding Coatings for Fast Neutron Detection

    International Nuclear Information System (INIS)

    Chandrashekhar, MVS

    2017-01-01

    The objective is to develop and implement a superior low-cost, large area (potentially >32in), easily deployable, close proximity, harsh environment innovative neutron sensor needed for next generation fuel cycle monitoring. We will exploit recent breakthroughs at the PI's lab on the electrochemistry of epitaxial graphene (EG) formed on commercial SiC wafers, a transformative nanomaterial system with superior radiation detection and durability properties to develop a new paradigm in detection for fast neutrons, a by-product of fission reactors. There are currently few effective detection/monitoring schemes, especially solid-state ones at present. This is essential for monitoring and control of future fuel cycles to make them more efficient and reliable. By exploiting these novel materials, as well as innovative hybrid SiC/EG/Cladding device architectures conceived by the team, will develop low-cost, high performance solutions to fast-neutron detection. Finally, we will also explore 3-terminal device implementations for neutron detectors with built-in electronic gain to further shrink these devices and improve their sensitivity.

  5. Overview and prospects of the application of fast neutrons in cancer therapy

    International Nuclear Information System (INIS)

    Wambersie, A.; Barendsen, G.W.; Breteau, N.

    1984-01-01

    Radiobiological data suggest that there ''must be'' clinical situations where fast neutrons have some advantages compared to low-LET radiations. Clinical experience, so far available, indicates that there exist tumour types or localizations, and patients series, where neutrontherapy actually brings a benefit compared to the current photon techniques. In addition, the indications for neutrontherapy, which can be predicted from the radiobiological data, correspond fairly well to the patient series for which a benefit for fast neutrons has been clinically observed (e.g. well differentiated, slowly growing tumours, large anoxic tumours). The advantage of combining neutrons and photons (mixed-schedule or boost) which is observed in several patient series is also consistent with the available radiobiological data (reduced differential effect with increasing LET). Clinical trials are now progressively confirming the conclusions of the pilot studies, and demonstrate that a statistically significant benefit can be obtained with neutrons for selected patient series. It can then reasonably be assumed that neutrontherapy will gain a place amongst the other radiotherapy techniques. The proportion of the patients which could benefit from neutrontherapy is difficult to evaluate so far (10 to 20%) but it is in any case sufficient to justify the installation of a limited number of additional neutrontherapy facilities

  6. The Radiative Capture Cross-Section of U 238 for Fast Neutrons

    International Nuclear Information System (INIS)

    Broda, E.

    1945-01-01

    This report was written by E. Broda and D.H. Wilkinson at the Cavendish Laboratory (Cambridge) in January 1945 and is about the radiative capture cross-section of U238 for fast neutrons. The Chemical procedure and beta counting, the notes on the activation of the samples, the results and an appendix as well as a short introduction can be found in this report. (nowak)

  7. A unified Monte Carlo approach to fast neutron cross section data evaluation.

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.; Nuclear Engineering Division

    2008-03-03

    A unified Monte Carlo (UMC) approach to fast neutron cross section data evaluation that incorporates both model-calculated and experimental information is described. The method is based on applications of Bayes Theorem and the Principle of Maximum Entropy as well as on fundamental definitions from probability theory. This report describes the formalism, discusses various practical considerations, and examines a few numerical examples in some detail.

  8. The effects of fast-neutron irradiation on the mechanical properties of austenitic stainless steel

    International Nuclear Information System (INIS)

    Dalton, J.H.

    1978-01-01

    The paper reviews the effects of fast-neutron irradiation on the tensile properties of austenitic stainless steels at irradiation temperatures of less than 400 degrees Celcius, using as an example, work carried out at Pelindaba on an AISI 316 type steel produced in South Africa. Damage produced in these steels at higher irradiation temperatures and fluences is also briefly discussed. The paper concludes with a discussion of some methods of overcoming or decreasing the effects of irradiation damage [af

  9. Radiation Detection and Classification of Heavy Oxide Inorganic Scintillator Crystals for Detection of Fast Neutrons

    Science.gov (United States)

    2016-06-01

    detection. According to Glasstone and Dolan [4] as well as numerous other experts, there are fundamentally three isotopes that could practically be used ...et al., “High effective fast neutron detectors based on inorganic scintillators,” Presented at 2014 IEEE Nuclear Science Symposium & Medical Imaging ...to the Office of Management and Budget, Paperwork Reduction Project (0704-0188) Washington, DC 20503. 1. AGENCY USE ONLY (Leave blank) 2. REPORT

  10. DETERMINATION OF LIMIT DETECTION OF THE ELEMENTS N, P, K, Si, Al, Fe, Cu, Cd, WITH FAST NEUTRON ACTIVATION USING NEUTRON GENERATOR

    Directory of Open Access Journals (Sweden)

    Sunardi Sunardi

    2010-06-01

    Full Text Available Determination of limit detection of the elements N, P, K, Si, Al, Fe, Cu, Cd, with fast neutron activation using neutron generator has been done.  Samples prepared from SRM 2704, N, P, K elements from MERCK, Cu, Cd, Al from activation foil made in San Carlos, weighted and packed for certain weight then iradiated during 30 minutes with 14 MeV fast neutron using the neutron generator and then counted with gamma spectrometry (accuspec.  At this research condition of neutron generator was set at current 1 mA that produced neutron flux about 5,47.107 n/cm2.s and  experimental result shown that the limit detection for the elements N, P, K, Si, Al, Fe, Cu, Cd are  2,44 ppm, 1,88 ppm, 2,15 ppm, 1,44 ppm, 1,26 ppm, 1,35 ppm, 1,05 ppm, 2,99 ppm, respectively.  The data  indicate that the limit detection or sensitivity of appliance of neutron generator to analyze the element is very good, which is feasible to get accreditation AANC laboratory using neutron generator.   Keywords: limit detection, AANC, neutron generator

  11. Contribution to uncertainties evaluation for fast reactors neutronic cross sections

    International Nuclear Information System (INIS)

    Privas, Edwin

    2015-01-01

    The thesis has been motivated by a wish to increase the uncertainty knowledge on nuclear data, for safety criteria. It aims the cross sections required by core calculation for sodium fast reactors (SFR), and new tools to evaluate its.The main objective of this work is to provide new tools in order to create coherent evaluated files, with reliable and mastered uncertainties. To answer those problematic, several methods have been implemented within the CONRAD code, which is developed at CEA of Cadarache. After a summary of all the elements required to understand the evaluation world, stochastic methods are presented in order to solve the Bayesian inference. They give the evaluator more information about probability density and they also can be used as validation tools. The algorithms have been successfully tested, despite long calculation time. Then, microscopic constraints have been implemented in CONRAD. They are defined as new information that should be taken into account during the evaluation process. An algorithm has been developed in order to solve, for example, continuity issues between two energy domains, with the Lagrange multiplier formalism. Another method is given by using a marginalization procedure, in order to either complete an existing evaluation with new covariance or add systematic uncertainty on an experiment described by two theories. The algorithms are well performed along examples, such the 238 U total cross section. The last parts focus on the integral data feedback, using methods of integral data assimilation to reduce the uncertainties on cross sections. This work ends with uncertainty reduction on key nuclear reactions, such the capture and fission cross sections of 238 U and 239 Pu, thanks to PROFIL and PROFIL-2 experiments in Phenix and the Jezebel benchmark. (author) [fr

  12. Calculation of gamma-rays and fast neutrons fluxes with the program Mercure-4

    International Nuclear Information System (INIS)

    Baur, A.; Dupont, C.; Totth, B.

    1978-01-01

    The program MERCURE-4 evaluates gamma ray or fast neutron attenuation, through laminated or bulky three-dimensionnal shields. The method used is that of line of sight point attenuation kernel, the scattered rays being taken into account by means of build-up factors for γ and removal cross sections for fast neutrons. The integration of the point kernel over the range of sources distributed in space and energy, is performed by the Monte-Carlo method, with an automatic adjustment of the importance functions. Since it is operationnal the program MERCURE-4 has been intensively used for many various problems, for example: - the calculation of gamma heating in reactor cores, control rods and shielding screens, as well as in experimental devices and irradiation loops; - the evaluation of fast neutron fluxes and corresponding damage in structural materials of reactors (vessel steels...); - the estimation of gamma dose rates on nuclear instrumentation in the reactors, around the reactor circuits and around spent fuel shipping casks

  13. Radiolysis of water at elevated temperatures with γ-rays and fast neutrons

    International Nuclear Information System (INIS)

    Katsumura, Y.; Sunaryo, G.R.; Hiroishi, D.; Ishigure, K.

    1995-01-01

    Determination of G-values of water decomposition products in neutral water produced by irradiation with gamma-rays and fast neutrons at elevated temperatures up to 250degC was carried out by a combination of NaNO 2 , acetone + methanol, and HClO 4 + methanol solutions. In the gamma-radiolysis, the G-values obtained in the present experiment are in good agreement with recently reported ones except G OH and G H2O2 . In the fast neutron radiolysis, although a similar change of the G-values with temperature was observed, the higher molecular yields of G H2 and G H2O2 and lower radical ones of G H and, especially, G e-aq were determined. It was made clear that the LET effect still remains even at elevated temperatures. It suggests that the spur size would expand at higher temperatures and the fraction of the intraspur reactions decreases. Furthermore, in order to clarify the characteristics of the determined G-values, computer simulations under the simplified conditions in nuclear reactors have been carried out. The G-values for fast neutron radiolysis give a significant influence to the result. It was pointed out by the simulations that reverse reactions for H 2 + OH → H + H 2 O and e - aq + H + → H, which can be neglected at room temperature, become important at higher temperatures. (author)

  14. High-frame rate imaging of two-phase flow in a thin rectangular channel using fast neutrons.

    Science.gov (United States)

    Zboray, R; Mor, I; Dangendorf, V; Stark, M; Tittelmeier, K; Cortesi, M; Adams, R

    2014-08-01

    We have demonstrated the feasibility of performing high-frame-rate, fast neutron radiography of air-water two-phase flows in a thin channel with rectangular cross section. The experiments have been carried out at the accelerator facility of the Physikalisch-Technische Bundesanstalt. A polychromatic, high-intensity fast neutron beam with average energy of 6 MeV was produced by 11.5 MeV deuterons hitting a thick Be target. Image sequences down to 10 ms exposure times were obtained using a fast-neutron imaging detector developed in the context of fast-neutron resonance imaging. Different two-phase flow regimes such as bubbly slug and churn flows have been examined. Two phase flow parameters like the volumetric gas fraction, bubble size and mean bubble velocities have been measured. The first results are promising, improvements for future experiments are also discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Study of the elemental composition of Chenopodium Quinoa Willd by fast neutron activation analysis and X ray fluorescence analysis

    International Nuclear Information System (INIS)

    Soto Moran, R.L.; Szegedi, S.; Llopiz, J.L.

    1996-01-01

    By means of x-ray fluorescence and fast neutron activation analysis the nitrogen content has been determined in samples of roots, stems, leaf, flowers and grains from Quinua (Chenopodium Quinoa Willd), which was previously treated with fertilizer

  16. Pulse shape discrimination between (fast or thermal) neutrons and gamma rays with plastic scintillators: State of the art

    Energy Technology Data Exchange (ETDEWEB)

    Bertrand, Guillaume H.V. [CEA, LIST, Laboratoire Capteurs & Architectures Électroniques, CEA Saclay, F-91191 Gif-sur-Yvette cedex (France); Hamel, Matthieu, E-mail: matthieu.hamel@cea.fr [CEA, LIST, Laboratoire Capteurs & Architectures Électroniques, CEA Saclay, F-91191 Gif-sur-Yvette cedex (France); Normand, Stéphane [CEA, DAM, Le Ponant, 25 rue Leblanc, F-75015 Paris (France); Sguerra, Fabien [CEA, LIST, Laboratoire Capteurs & Architectures Électroniques, CEA Saclay, F-91191 Gif-sur-Yvette cedex (France)

    2015-03-11

    We would like to present here with the eyes of the chemist the most recent developments of plastic scintillators (PS) for neutron detection. This review covers the period from 2000 to August 2014, and is fragmented in two main chapters. The first chapter deals with the chemical modifications for thermal neutron capture, whereas the second chapter presents the various strategies used to enhance the response to fast neutrons via pulse shape discrimination. For each chapter the theory is also explained.

  17. Pulse shape discrimination between (fast or thermal) neutrons and gamma rays with plastic scintillators: State of the art

    Science.gov (United States)

    Bertrand, Guillaume H. V.; Hamel, Matthieu; Normand, Stéphane; Sguerra, Fabien

    2015-03-01

    We would like to present here with the eyes of the chemist the most recent developments of plastic scintillators (PS) for neutron detection. This review covers the period from 2000 to August 2014, and is fragmented in two main chapters. The first chapter deals with the chemical modifications for thermal neutron capture, whereas the second chapter presents the various strategies used to enhance the response to fast neutrons via pulse shape discrimination. For each chapter the theory is also explained.

  18. Neutronics - thermal-hydraulics coupling: application to the helium-cooled fast reactor

    International Nuclear Information System (INIS)

    Vaiana, F.

    2009-11-01

    This thesis focuses on the study of interactions between neutron-kinetics and thermal-hydraulics. Neutron-kinetics allow to calculate the power in a nuclear reactor and the temperature evolution of materials where this power is deposited is known thanks to thermal-hydraulics. Moreover, when the temperatures evolve, the densities and cross sections change. These two disciplines are thus coupled. The first part of this work corresponds to the study and development of a method which allows to simulate transients in nuclear reactors and especially with a Monte-Carlo code for neutron-kinetics. An algorithm for the resolution of the neutron transport equation has been established and validated with a benchmark. In thermal-hydraulics, a porous media approach, based on another thesis, is considered. This gives the opportunity to solve the equations on the whole core without unconscionable computation time. Finally, a theoretical study has been performed on the statistical uncertainties which result from the use of a Monte-Carlo code and which spread from the reactivity to the power and from the power to the temperatures. The second part deals with the study of a misplaced control rod withdrawing in a GFR (helium-cooled fast reactor), a fourth generation reactor. Some models allowing to calculate neutron-kinetics and thermal-hydraulics in the core (which contains assemblies built up with fuel plates) were defined. In thermal-hydraulics, a model for the core based on the porous media approach and a fuel plate homogenization model have been set up. A similar homogenization model has been studied for neutron-kinetics. Finally, the control rod withdrawing transient where we can observe the power raising and the stabilisation by thermal feedback has been performed with the Monte-Carlo code Tripoli for neutron-kinetics and the code Trio-U for thermal-hydraulics. (author)

  19. Self powered neutron detectors as in-core detectors for Sodium-cooled Fast Reactors

    Science.gov (United States)

    Verma, V.; Barbot, L.; Filliatre, P.; Hellesen, C.; Jammes, C.; Svärd, S. Jacobsson

    2017-07-01

    Neutron flux monitoring system forms an integral part of the design of a Generation IV sodium cooled fast reactor. Diverse possibilities of detector system installation must be studied for various locations in the reactor vessel in order to detect any perturbations in the core. Results from a previous paper indicated that it is possible to detect changes in neutron source distribution initiated by an inadvertent withdrawal of outer control rod with in-vessel fission chambers located azimuthally around the core. It is, however, not possible to follow inner control rod withdrawal and precisely know the location of the perturbation in the core. Hence the use of complimentary in-core detectors coupled with the peripheral fission chambers is proposed to enable robust core monitoring across the radial direction. In this paper, we assess the feasibility of using self-powered neutron detectors (SPNDs) as in-core detectors in fast reactors for detecting local changes in the power distribution when the reactor is operated at nominal power. We study the neutron and gamma contributions to the total output current of the detector modelled with Platinum as the emitter material. It is shown that this SPND placed in an SFR-like environment would give a sufficiently measurable prompt neutron induced current of the order of 600 nA/m. The corresponding induced current in the connecting cable is two orders of magnitude lower and can be neglected. This means that the SPND can follow in-core power fluctuations. This validates the operability of an SPND in an SFR-like environment.

  20. Monte Carlo evaluation of a photon pencil kernel algorithm applied to fast neutron therapy treatment planning

    Science.gov (United States)

    Söderberg, Jonas; Alm Carlsson, Gudrun; Ahnesjö, Anders

    2003-10-01

    When dedicated software is lacking, treatment planning for fast neutron therapy is sometimes performed using dose calculation algorithms designed for photon beam therapy. In this work Monte Carlo derived neutron pencil kernels in water were parametrized using the photon dose algorithm implemented in the Nucletron TMS (treatment management system) treatment planning system. A rectangular fast-neutron fluence spectrum with energies 0-40 MeV (resembling a polyethylene filtered p(41)+ Be spectrum) was used. Central axis depth doses and lateral dose distributions were calculated and compared with the corresponding dose distributions from Monte Carlo calculations for homogeneous water and heterogeneous slab phantoms. All absorbed doses were normalized to the reference dose at 10 cm depth for a field of radius 5.6 cm in a 30 × 40 × 20 cm3 water test phantom. Agreement to within 7% was found in both the lateral and the depth dose distributions. The deviations could be explained as due to differences in size between the test phantom and that used in deriving the pencil kernel (radius 200 cm, thickness 50 cm). In the heterogeneous phantom, the TMS, with a directly applied neutron pencil kernel, and Monte Carlo calculated absorbed doses agree approximately for muscle but show large deviations for media such as adipose or bone. For the latter media, agreement was substantially improved by correcting the absorbed doses calculated in TMS with the neutron kerma factor ratio and the stopping power ratio between tissue and water. The multipurpose Monte Carlo code FLUKA was used both in calculating the pencil kernel and in direct calculations of absorbed dose in the phantom.

  1. The study of creep in stainless steel irradiated with fast neutron and alpha particles

    International Nuclear Information System (INIS)

    Correa, D.A.C.

    1985-01-01

    The objective of the present work is to study the creep behavior of the 316 type stainless steel 50% cold worked in different conditions of temperature and applied stress, after neutron radiation and Alfa particles implantation. For this experiment, non-irradiated samples, samples irradiated in the research reactor IEA-R1 with fast neutron (E≥ MeV) up to a fluence of 8.6.10 17 n/cm 2 , and samples implanted with Alfa particles in the cyclotron CV-28 with Helium concentrations of 5 and 26 appm, were creep tested with applied stresses of the 200-300 MPa at temperatures between 650 0 C and 700 0 C. The deformation versus time curves were plotted and it was observed tha the second stage is not well defined, with the creep rate increasing continuously until the occurrence of failure of the material. The study of the effect of increase from 200 MPa to 300 MPa at the same temperature was performed. It can be concluded that this increase produces an approximately 70% reductions in the fracture time of the material, with practically no influence in the total deformation. Samples were tested at different temperatures (650, 675 and 700 0 C) at a same applied stress (200 MPa). It has been observed that a temperature of 50 0 C produces 98,9% of reduction in the fracture time and almost doubles the total deformation. On neutron irradiated samples, creep tests were performed at the same temperature and stress of the non irradiated samples. Comparing the results obtained a tendency of embrittlement due to the neutron irradiation can be observed; no remarkable structure changes were detected due to small fast neutron. Microstructural and metalographic observations were performed before and after each creep test. (author) [pt

  2. Simulation of silicon microdosimetry spectra in fast neutron therapy using the GEANT4 Monte Carlo toolkit

    International Nuclear Information System (INIS)

    Cornelius, I.M.; Rosenfeld, A.B.

    2003-01-01

    Microdosimetry is used to predict the biological effects of the densely ionizing radiation environments of hadron therapy and space. The creation of a solid state microdosimeter to replace the conventional Tissue Equivalent Proportional Counter (TEPC) is a topic of ongoing research. The Centre for Medical Radiation Physics has been investigating a technique using microscopic arrays of reverse biased PN junctions. A prototype silicon-on-insulator (SOI) microdosimeter was developed and preliminary measurements have been conducted at several hadron therapy facilities. Several factors impede the application of silicon microdosimeters to hadron therapy. One of the major limitations is that of tissue equivalence, ideally the silicon microdosimeter should provide a microdosimetry distribution identical to that of a microscopic volume of tissue. For microdosimetry in neutron fields, such as Fast Neutron Therapy, it is important that products resulting from neutron interactions in the non tissue equivalent sensitive volume do not contribute significantly to the spectrum. Experimental measurements have been conducted at the Gershenson Radiation Oncology Center, Harper Hospital, Detroit by Bradley et al. The aim was to provide a comparison with measurements performed with a TEPC under identical experimental conditions. Monte Carlo based calculations of these measurements were made using the GEANT4 Monte Carlo toolkit. Agreement between experimental and theoretical results was observed. The model illustrated the importance of neutron interactions in the non tissue equivalent sensitive volume and showed this effect to decrease with sensitive volume size as expected. Simulations were also performed for 1 micron cubic silicon sensitive volumes embedded in tissue equivalent material to predict the best case scenario for silicon microdosimetry in Fast Neutron Therapy

  3. Effect of low level doses of fast neutrons on the activity of the snake venom

    International Nuclear Information System (INIS)

    Hanafy, Magda S.; Amin, Aida M.

    1998-01-01

    In this work, the effect of low level doses of fast neutrons from 252 Cf on snake venom (Cerastes cerastes) was studied through measurements of biophysical and haematological changes. The absorption spectrum (200-700 nm) of haemoglobin (Hb) collected from the blood of rats after 3 and 24 hours post injection with irradiated and non-irradiated snake venom with neutron fluences of 3x10 6 , 2.8x10 7 and 3X10 8 n/cm 2 was measured. The results indicated that injection of animals with either non- irradiated or irradiated venom ( with different neutron fluences) resulted into the decrease of the absorption band intensities of Hb. These changes in the properties of the characteristic band showed to be a marker for irradiated venom and is dose dependent. It was concluded that neutron irradiation of the venom leads to the decrease of its toxicity and, consequently, to the increase of the chance of repair mechanism in livings. Obvious changes of most haematological erythrocytic values of Hb, packed cell volume (PCV), red blood counts (RBC), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCHb) and mean corpuscular haemoglobin concentration (MCHC) were observed in the blood of the rats injected with non-irradiated venom (as a first group) and those injected with the irradiated venom (as a second group). The microcytic haemolytic anemia was more acute in the first group than in the second one which showed lesser extent. It is concluded from this study that low level doses of fast neutrons could postpone and lower acute haematological action induced by the venom. (authors)

  4. The fast neutron facility at the research reactor Munich. Determination of the beam quality and medical applications

    International Nuclear Information System (INIS)

    Wagner, F. M.; Koester, L.

    1990-01-01

    At the research reactor FRM, fast and epithermal neutron beams are generated by a thermal-to-fast neutron converter and/or near core scatterers. The dosimetry and spectroscopy of the resulting intense mixed beams of neutron and gamma radiation with a wide range of energies set spetial tasks for neutron dosimetry and spectroscopy. The twin chamber method and some others are briefly described. Neutron spectroscopy is performed by a Li-6 sandwich spectrometer covering the full neutron spectrum of a well-collimated mixed beam from about 20 keV to 8 MeV. The data registration is assisted by a microcomputer which generates sum and triton spectra on-line. Sum analysis is applied to neutron energies greater than 0.3 MeV; the intermediate neutron spectrum is evaluated by unfolding of the triton spectrum. Moreover, a brief overview of the reactor neutron therapy (RENT) at the FRM is given. After a number of animal experiments for the determination of the biological effectiveness relative to X-rays, clinical irradiations have been started in 1985. The most important indications for RENT are listed. 140 patients with bad prognoses have been treated since. The average tumour control rate of 60% is surprisingly high. Possibilities for an assisting Boron Neutron Capture Therapy (BNCT) are shown. 8 figs., 23 refs

  5. Neutron physics

    International Nuclear Information System (INIS)

    Beckurts, K.H.; Wirtz, K.

    1974-01-01

    This textbook consists of four sections which deal with the following subjects: 1. Production of neutrons and their interactions with the nuclei; neutron sources; neutron detectors; cross-section measurements. 2. Theory of neutron interactions with macroscopic media; neutron slowing down; space distribution of moderated neutrons; neutron thermalization; neutron scattering. 3. Radioactive probe measurements of thermal neutron fluxes; activation by means of epithermal neutrons; threshold detectors of fast neutrons; neutron calibration. 4. Neutron energy; slowing down kernels; neutron age; diffusion length and absorption of neutrons

  6. Design optimization, manufacture and response measurements for fast-neutron radiography converters made of scintillator and wavelength-shifting fibers

    Science.gov (United States)

    Li, Hang; Wu, Yang; Cao, Chao; Huo, Heyong; Tang, Bin

    2014-10-01

    In order to improve the image quality of fast neutron radiography, a converter made of scintillator and wavelength-shifting fibers has been developed. The appropriate parameters of the converter such as fibers arrangement, distance between fibers are optimized theoretically, and manufacture of the converter are also optimized. Fast neutron radiography experiments by 14 MeV neutrons are used to test this converter and kinds of traditional converters. The experiments' results matched the calculations. The novel converter's resolution is better than 1 mm and the light output is high.

  7. A novel fast-neutron tomography system based on a plastic scintillator array and a compact D–D neutron generator

    International Nuclear Information System (INIS)

    Adams, Robert; Zboray, Robert; Prasser, Horst-Michael

    2016-01-01

    Very few experimental imaging studies using a compact neutron generator have been published, and to the knowledge of the authors none have included tomography results using multiple projection angles. Radiography results with a neutron generator, scintillator screen, and camera can be seen in Bogolubov et al. (2005), Cremer et al. (2012), and Li et al. (2014). Comparable results with a position-sensitive photomultiplier tube can be seen in Popov et al. (2011). One study using an array of individual fast neutron detectors in the context of cargo scanning for security purposes is detailed in Eberhardt et al. (2005). In that case, however, the emphasis was on very large objects with a resolution on the order of 1 cm, whereas this study focuses on less massive objects and a finer spatial resolution. In Andersson et al. (2014) three fast neutron counters and a D–T generator were used to perform attenuation measurements of test phantoms. Based on the axisymmetry of the test phantoms, the single-projection information was used to calculate radial attenuation distributions of the object, which was compared with the known geometry. In this paper a fast-neutron tomography system based on an array of individual detectors and a purpose-designed compact D–D neutron generator is presented. Each of the 88 detectors consists of a plastic scintillator read out by two Silicon photomultipliers and a dedicated pulse-processing board. Data acquisition for all channels was handled by four single-board microcontrollers. Details of the individual detector design and testing are elaborated upon. Using the complete array, several fast-neutron images of test phantoms were reconstructed, one of which was compared with results using a Co-60 gamma source. The system was shown to be capable of 2 mm resolution, with exposure times on the order of several hours per reconstructed tomogram. Details about these measurements and the analysis of the reconstructed images are given, along with a

  8. Developments and application of neutron noise diagnostics of sodium cooled fast reactors

    International Nuclear Information System (INIS)

    Zylbersztejn, F.

    2013-01-01

    The Sodium cooled Fast Reactor (SFR) is one of the six reactor types selected by the Generation-IV international forum (GIF), and the building of an industrial prototype is planned in France. The safety standard of the future SFR has to be equivalent to the EPR's. The general improvement of the safety of the new reactor goes through the examination of all the potentially harmful scenarios and both the study and monitoring of early signs. The mechanical deformations of the core can have harmful consequences in sodium fast reactors, such as unexpected power variations due to the reactivity increase in case of core compaction, or the excessive deterioration of the mechanical structures. The monitoring of such phenomena and of their potential early signs is then needed. The monitoring of such phenomena can be done with neutron detectors placed inside and outside the tank. This PhD thesis deals with the study of the neutron noise generated by the periodic deformation of the SFR core, restricted to the so-called core compaction or core flowering phenomenon, a deformation consisting in the variation of the inter-assembly sodium width by a radial bending the assemblies (the assemblies in SFR are held by the base). The PhD thesis has been performed within collaboration between CEA (France) and Chalmers Institute of Technology (Sweden). The work realized during the thesis led to the publication of 3 articles as first author and another as second author. This work has embraced the following topics: A state of the art of the monitoring of the core deformation phenomenon by interpretation of the noise measurements in SFR has been done. The PHENIX reactor multi physics measurements database has been scrutinized to provide an interpretation of the neutron noise bringing out mechanical vibration phenomena. An important conclusion was that the lack of theoretical knowledge about the neutron noise induced by the vibration phenomenon and the ill positioning of the neutron detectors

  9. MONDO: A tracker for the characterization of secondary fast and ultrafast neutrons emitted in particle therapy

    Science.gov (United States)

    Mirabelli, R.; Battistoni, G.; Giacometti, V.; Patera, V.; Pinci, D.; Sarti, A.; Sciubba, A.; Traini, G.; Marafini, M.

    2018-01-01

    In Particle Therapy (PT) accelerated charged particles and light ions are used for treating tumors. One of the main limitation to the precision of PT is the emission of secondary particles due to the beam interaction with the patient: secondary emitted neutrons can release a significant dose far from the tumor. Therefore, a precise characterization of their flux, production energy and angle distribution is eagerly needed in order to improve the Treatment Planning Systems (TPS) codes. The principal aim of the MONDO (MOnitor for Neutron Dose in hadrOntherapy) project is the development of a tracking device optimized for the detection of fast and ultra-fast secondary neutrons emitted in PT. The detector consists of a matrix of scintillating square fibres coupled with a CMOS-based readout. Here, we present the characterization of the detector tracker prototype and CMOS-based digital SPAD (Single Photon Avalanche Diode) array sensor tested with protons at the Beam Test Facility (Frascati, Italy) and at the Proton Therapy Centre (Trento, Italy), respectively.

  10. Fast neutron dosimetry using CR-39 track detectors with polyethylene as radiator

    International Nuclear Information System (INIS)

    Castillo, F.; Espinosa, G.; Golzarri, J.I.; Osorio, D.; Rangel, J.; Reyes, P.G.; Herrera, J.J.E.

    2013-01-01

    The chemical etching parameters (etching time, temperature, normality of etchant, etc.) for the use of CR-39 (allyl diglycol carbonate – Lantrack ® ) as a fast neutron dosimeter have been optimized. The CR-39 chips, placed under a 1.5 mm polyethylene radiator, were exposed for calibration to an 241 Am-Be source at different time intervals for a given neutron fluence. After several chemical etching processes of the detectors with different conditions, the optimum characteristics for the chemical etching were found at 6N KOH solution, 60 ± 1 °C, for 12 h. An accurate relationship between the dose and fluence calculations was obtained as a function of the track density. - Highlights: ► Optimum etching time for fast neutron irradiated CR-39 track detectors is found. ► Relationship between dose and fluence obtained as a function of the track density. ► Results are consistent with those reported elsewhere, and extend the dose range

  11. Computed Tomography with X-rays and Fast Neutrons for Restoration of Wooden Artwork

    Science.gov (United States)

    Osterloh, Kurt; Bellon, Carsten; Hohendorf, Stefan; Kolkoori, Sanjeevareddy; Wrobel, Norma; Nusser, Amélie; Freitag, Markus; Bücherl, Thomas; Bar, Doron; Mor, Ilan; Tamin, Noam; Weiss-Babai, Ruth; Bromberger, Benjamin; Dangendorf, Volker; Tittelmeier, Kai

    The objects of this investigation were sculptures taken from a ca. three hundred years old baroque epitaph of a church in Tönning, a town in Northern Germany. Around 1900 it was found in a disastrous state heavily damaged by wood-worm. At that time, the whole artwork was treated with the tar extract carbolineum as a remedy. Nowadays, this substance has been identified as carcinogenic, and its presence can be perceived by its stench and visually at certain spots on the surface where it has penetrated the covering paint. A gold-painted sculpture of a massive wooden skull was interrogated with X-rays and fast neutrons to investigate the internal distribution of the carbolineum. The X-ray tomography, with its excellent spatial resolution revealed galleries left over from the worm infestation in the outer areas and cracks in the central region. The golden color coating appeared as a thick and dense layer. In comparison the tomography with fast neutrons, though being of lower resolution and yet unresolved artefacts revealed sections of slightly different densities in the bulk of the wood. These differences we attribute to the differences in the distribution of the impregnant in the wood, visible due to its higher hydrogen content making it less transparent for neutrons.

  12. Interim assessment of the experience of fast neutron therapy in Edinburgh

    International Nuclear Information System (INIS)

    Duncan, W.; Arnott, S.J.

    1982-01-01

    Clinical studies of fast neutron therapy were started in Edinburgh in March 1977. The treatment facility has an isocentric machine and a fixed horizontal beam. The neutron beam is produced by 15 MeV deuterons on a thick beryllium target. Six hundred and forty-one patients have been included in these studies in the four-year period to March 1981. Randomly controlled trials have been conducted since May 1977 and 376 patients have been recruited in this period. The local tumor response rates and morbidity observed is given for trials of patients with cerebral gliomass, squamous carcinoma of the head and neck region, transitional cell carcinoma of the bladder and adenocarcinoma of the rectum. This interim evaluation does not demonstrate any advantage of fast neutron radiotherapy as compared with photon therapy. However, greater numbers of patients require to be studied and followed-up for longer intervals. A definitive assessment of the randomly controlled clinical trials in Edinburgh should be possible at the end of 1982

  13. On the contradiction between the microscopic and integral data for fast neutron absorption cross-section for 238U nuclei

    International Nuclear Information System (INIS)

    Van'kov, A.A.

    1994-01-01

    The contradiction between a measured integral neutron absorption cross-section averaged over a fast reactor spectrum and the corresponding value which was calculated with the use of evaluated microscopic cross-sections and a theoretical neutron spectrum has been investigated. The possible systematic error of a correction factor which takes into account multiple resonance neutron scattering in samples used in the measurement of the absorption cross-section is investigated. It is proposed that this error may be one of the main reason for the contradiction mentioned above which arises in the measurement of the 236 U neutron absorption cross-section. (author). 13 refs, 3 figs

  14. Optimisation of a collimator array for a multi-detector time-of-flight spectrometer for fast neutrons

    International Nuclear Information System (INIS)

    Schlegel-Bickmann, D.

    1979-01-01

    A Monte Carlo program has been developed which calculates the neutron background due to the interaction between incident neutrons and the collimator fan near the detector in dependence of geometry and material parameters. The position of the neutron source with regard to the collimators may be chosen at random. The program is also suitable for other three-dimensional transport problems of fast neutrons in the energy range between 0.5 and 20 MeV. The modular structure makes it easy to adapt it to highly specific problems. (orig.) 891 HP 892 MB [de

  15. Novel design concepts for generating intense accelerator based beams of mono-energetic fast neutrons

    International Nuclear Information System (INIS)

    Franklyn, C.B.; Govender, K.; Guzek, J.; Beer, A. de; Tapper, U.A.S.

    2001-01-01

    Full text: Successful application of neutron techniques in research, medicine and industry depends on the availability of suitable neutron sources. This is particularly important for techniques that require mono-energetic fast neutrons with well defined energy spread. There are a limited number of nuclear reactions available for neutron production and often the reaction yield is low, particularly for thin targets required for the production of mono-energetic neutron beams. Moreover, desired target materials are often in a gaseous form, such as the reactions D(d,n) 3 He and T(d,n) 3 He, requiring innovative design of targets, with sufficient target pressure and particle beam handling capability. Additional requirements, particularly important in industrial applications, and for research institutions with limited funds, are the cost effectiveness as well as small size, coupled with reliable and continuous operation of the system. Neutron sources based on high-power, compact radio-frequency quadrupole (RFQ) linacs can satisfy these criteria, if used with a suitable target system. This paper discusses the characteristics of a deuteron RFQ linear accelerator system coupled to a high pressure differentially pumped deuterium target. Such a source, provides in excess of 10 10 mono- energetic neutrons per second with minimal slow neutron and gamma-ray contamination, and is utilised for a variety of applications in the field of mineral identification and materials diagnostics. There is also the possibility of utilising a proposed enhanced system for isotope production. The RFQ linear accelerator consists of: 1) Deuterium 25 keV ion source injector; 2) Two close-coupled RFQ resonators, each powered by an rf amplifier supplying up to 300 kW of peak power at 425 MHz; 3) High energy beam transport system consisting of a beam line, a toroid for beam current monitoring, two steering magnets and a quadrupole triplet for beam focusing. Basic technical specifications of the RFQ linac

  16. Fast neutron counting in a mobile, trailer-based search platform

    Directory of Open Access Journals (Sweden)

    Hayward Jason P.

    2017-01-01

    Full Text Available Trailer-based search platforms for detection of radiological and nuclear threats are often based upon coded aperture gamma-ray imaging, because this method can be rendered insensitive to local variations in gamma background while still localizing the source well. Since gamma source emissions are rather easily shielded, in this work we consider the addition of fast neutron counting to a mobile platform for detection of sources containing Pu. A proof-of-concept system capable of combined gamma and neutron coded-aperture imaging was built inside of a trailer and used to detect a 252Cf source while driving along a roadway. Neutron detector types employed included EJ-309 in a detector plane and EJ-299-33 in a front mask plane. While the 252Cf gamma emissions were not readily detectable while driving by at 16.9 m standoff, the neutron emissions can be detected while moving. Mobile detection performance for this system and a scaled-up system design are presented, along with implications for threat sensing.

  17. Irradiation Effects for the Pulsed Fast Neutron Analysis (PFNA) Cargo Interrogation System

    Energy Technology Data Exchange (ETDEWEB)

    Slater, C.O.

    2001-02-02

    At the request of Safety and Ecology Corporation of Tennessee, radiation effects of the proposed Pulsed Fast Neutron Analysis (PFNA) Cargo Interrogation System have been examined. First, fissile cargo were examined to determine if a significant neutron signal would be observable during interrogation. Results indicated that ample multiplication would be seen for near critical bare targets. The water-reflected sphere showed relatively little multiplication. By implication, a fissile target shielded by hydrogenous cargo might not be detectable by neutron interrogation, particularly if reliance is placed on the neutron signal. The cargo may be detectable if use can be made of the ample increase in the photon signal. Second, dose rates were calculated at various locations within and just outside the facility building. These results showed that some dose rates may be higher than the target dose rate of 0.05 mrem/h. However, with limited exposure time, the total dose may be well below the allowed total dose. Lastly, estimates were made of the activation of structures and typical cargo. Most cargo will not be exposed long enough to be activated to levels of concern. On the other hand, portions of the structure may experience buildup of some radionuclides to levels of concern.

  18. Hair 32P measurement for body dose mapping in non-fatal exposures to fast neutrons.

    Science.gov (United States)

    Mianji, Fereidoun A; Jafari, Sheyda; Zaryouni, Saiedeh; Hajizadeh, Bardia

    2015-03-01

    Dosimetry bioassay methods are the backbone of a personal dosimetry in criticality accidents. Although methods like hair dosimetry and the use of activation foils (e.g., (32)S) have been employed for decades, capabilities of different techniques, effects of hair type and neutron spectrum on the dose response, sensitivity and uncertainties of different techniques, etc., need more investigations. For this reason, the use of the (32)S(n,p)(32)P reaction and hair samples for estimating non-fatal doses from fast neutrons was studied. The experiments were carried out with the hair samples attached on a RANDO phantom in a Cf-252 neutron field, in the dose range of about 0.05-1.15 Gy. In addition, the adequate post-accident preparation for hair samples including optimum conditioning and timing were investigated. Experimental results prove the good sensitivity and merit of the method for neutron quantification in the mentioned dose range for which other bioassay methods are of poor resolution and sensitivity. A rough estimation of the dose-response curve for Iranian hair was also derived.

  19. Fast neutron counting in a mobile, trailer-based search platform

    Science.gov (United States)

    Hayward, Jason P.; Sparger, John; Fabris, Lorenzo; Newby, Robert J.

    2017-12-01

    Trailer-based search platforms for detection of radiological and nuclear threats are often based upon coded aperture gamma-ray imaging, because this method can be rendered insensitive to local variations in gamma background while still localizing the source well. Since gamma source emissions are rather easily shielded, in this work we consider the addition of fast neutron counting to a mobile platform for detection of sources containing Pu. A proof-of-concept system capable of combined gamma and neutron coded-aperture imaging was built inside of a trailer and used to detect a 252Cf source while driving along a roadway. Neutron detector types employed included EJ-309 in a detector plane and EJ-299-33 in a front mask plane. While the 252Cf gamma emissions were not readily detectable while driving by at 16.9 m standoff, the neutron emissions can be detected while moving. Mobile detection performance for this system and a scaled-up system design are presented, along with implications for threat sensing.

  20. Radioactive Ion Beam Production by Fast-Neutron-Induced Fission in Actinide Targets at EURISOL

    CERN Document Server

    Herrera-Martínez, Adonai

    The European Isotope Separation On-Line Radioactive Ion Beam Facility (EURISOL) is set to be the 'next-generation' European Isotope Separation On-Line (ISOL) Radioactive Ion Beam (RIB) facility. It will extend and amplify current research on nuclear physics, nuclear astrophysics and fundamental interactions beyond the year 2010. In EURISOL, the production of high-intensity RIBs of specific neutron-rich isotopes is obtained by inducing fission in large-mass actinide targets. In our contribution, the use of uranium targets is shown to be advantageous to other materials, such as thorium. Therefore, in order to produce fissions in U-238 and reduce the plutonium inventory, a fast neutron energy spectrum is necessary. The large beam power required to achieve these RIB levels requires the use of a liquid proton-to-neutron converter. This article details the design parameters of the converter, with special attention to the coupled neutronics of the liquid converter and fission target. Calculations performed with the ...

  1. Standard Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of Nickel

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This test method covers procedures for measuring reaction rates by the activation reaction 58Ni(n,p)58Co. 1.2 This activation reaction is useful for measuring neutrons with energies above approximately 2.1 MeV and for irradiation times up to about 200 days in the absence of high thermal neutron fluence rates (for longer irradiations, see Practice E 261). 1.3 With suitable techniques fission-neutron fluence rates densities above 107 cm−2·s−1 can be determined. 1.4 Detailed procedures for other fast-neutron detectors are referenced in Practice E 261. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Note—The burnup corrections were com...

  2. Standard Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of Titanium

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This test method covers procedures for measuring reaction rates by the activation reactions 46Ti(n,p) 46Sc + 47Ti(n, np)46Sc. Note 1—Since the cross section for the (n,np) reaction is relatively small for energies less than 12 MeV and is not easily distinguished from that of the (n,p) reaction, this test method will refer to the (n,p) reaction only. 1.2 The reaction is useful for measuring neutrons with energies above approximately 4.4 MeV and for irradiation times up to about 250 days (for longer irradiations, see Practice E 261). 1.3 With suitable techniques, fission-neutron fluence rates above 109 cm–2·s–1 can be determined. However, in the presence of a high thermal-neutron fluence rate, 46Sc depletion should be investigated. 1.4 Detailed procedures for other fast-neutron detectors are referenced in Practice E 261. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 This standard does not purport to address all...

  3. Transient and chronic neurological complications of fast neutron radiation for adenocarcinoma of the prostate

    Energy Technology Data Exchange (ETDEWEB)

    Russell, K.J.; Laramore, G.E.; Wiens, L.W.; Griffeth, J.T.; Koh, W.J.; Griffin, B.R.; Austin-Seymour, M.M.; Griffin, T.W. (Washington Univ., Seattle, WA (USA). Lab. of Radiation Ecology); Krieger, J.N. (Washington University, Seattle (USA). Department of Urology); Davis, L.W. (Albert Einstein Coll. of Medicine, Bronx, NY (USA))

    1990-07-01

    The records of 132 patients participating in clinical trials using fast neutron (n = 94), mixed neutron and photon (n = 16), or conventional photon (n = 22) irradiation for primary management of prostatic cancer were retrospectively reviewed to assess treatment-related neurological complications. With a median follow-up of 14 months (range 1 to 101 months), 31/132 patients (26 neutron, 3 mixed beam, 2 photon) have experienced either sciatica beginning during or shortly after treatment, or diminished bladder or bowel continence that developed at a median time of 6.5 months following treatment. Sciatica responded to oral steroids and was usually self-limited, whereas sphincter dysfunction appears to be permanent. Pre-treatment risk factors for complications included a history of hypertension, diabetes, cigarette smoking or peripheral vascular disease, with 81% of affected patients having one or more risk factors compared witn 55% of unaffected patients (p = 0.01). Seven patients have moderate (5) or severe (2) residual problems, all in the cohorts receiving neutrons (6/7) or mixed beam therapy (1/7). (author). 31 refs.; 5 tabs.

  4. The fast neutrons reactors, the sodium, the fuel cycle: evaluation of the knowledge, innovation potential and forecast

    International Nuclear Information System (INIS)

    Moreau, J.

    2002-01-01

    This document presents the study, the design and the construction of fast neutrons reactors, cooled with sodium. From this evaluation, it details the innovation possibilities of this sector in the sustainable development context of the nuclear energy. Chapter one presents the physical and physico-chemical properties of the sodium. Chapter two analyzes the properties of the fast cores and the sodium advantages. Chapter three analyzes the great contribution of the EFR project. Chapter four takes stock on the innovation possibilities. And before the conclusion, chapter five shows that the fast neutrons reactors allow the electric power production in agreement with a sustainable development. (A.L.B.)

  5. Proceedings of the 14. International Symposium on the Interaction of Fast Neutrons with Nuclei - Neutron Generators and Application - organized by the Technical University of Dresden

    International Nuclear Information System (INIS)

    Seeliger, D.; Jahn, U.

    1985-07-01

    The symposium was devoted to current problems of intense fast neutron sources, especially 14 MeV DT-neutron generators, and their broad spectrum of application in nuclear physics. 56 participants from 12 countries and the IAEA demonstrate the high interest on this selected topics. The submitted contributions can be divided into two general parts. The first one gives a review about the different possibilities of the technical and technological solution in development, the present status of operation and also the problems connected with the use of intense neutron sources. Various experimental arrangements for neutron spectroscopy, determination of nuclear data and theoretical aspects are the content of the second part. The participation in this meeting of designer and operators on the one hand and users of neutron sources on the other hand was a good choice and stimulated productive discussions during the conference. (author)

  6. Spectrum measurement of fast neutron through air ducts in water, concrete, and lead

    International Nuclear Information System (INIS)

    Jiang, S.H.; Lin, G.L.; Wu, S.Y.; Liaw, S.Y.

    1983-01-01

    Fast neutron spectral through straight air ducts in water, concrete, and lead have been measured from 1 to 12 MeV by using an NE-213 spectrometer. Wall scattered component has been abstracted from the measured data. It was found that Simon and Clifford's equation can not be applied to describe the measured flux perhaps mainly due to the inadequate assumption of angular distribution of reflected neutrons. The ratio of wall-scattered component to line-of-sight component was found to be dependent on the duct length more or less with an inverse square proportionality for ducts in water and concrete and with an inverse cubic or even more strong proportionality for ducts in lead. (author)

  7. Large area imaging of hydrogenous materials using fast neutrons from a DD fusion generator

    Science.gov (United States)

    Cremer, J. T.; Williams, D. L.; Gary, C. K.; Piestrup, M. A.; Faber, D. R.; Fuller, M. J.; Vainionpaa, J. H.; Apodaca, M.; Pantell, R. H.; Feinstein, J.

    2012-05-01

    A small-laboratory fast-neutron generator and a large area detector were used to image hydrogen-bearing materials. The overall image resolution of 2.5 mm was determined by a knife-edge measurement. Contact images of objects were obtained in 5-50 min exposures by placing them close to a plastic scintillator at distances of 1.5 to 3.2 m from the neutron source. The generator produces 109 n/s from the DD fusion reaction at a small target. The combination of the DD-fusion generator and electronic camera permits both small laboratory and field-portable imaging of hydrogen-rich materials embedded in high density materials.

  8. Fast neutron spectrum in the reflector of swimming pool reactor behind metallics slabs

    International Nuclear Information System (INIS)

    Brousse, J.C.

    1970-01-01

    The large perturbations of fast neutron spectrum were measured behind lead, aluminium and iron slabs in the Siloette reflector at the CENG. The neutron slowing down is chiefly depending of the inelastic reaction. The reaction cross section increases with energy; a spectrum softening is deduced. This is verified. We tried to determine the spectrum shape by calculation to fit the measurements. Calculations were firstly made in unidimensional geometry by the NIOBE transport equation resolution code and by the SANE Monte-Carlo code. The results does not agree with the experimental determined values. Finally a semi-empirical method for studying a tridimensional geometry was chosen. We have obtained calculation results in a perfect agreement with measurements. The method is described. (author) [fr

  9. Determination of Substances Content of Soil Surface Using Fast Neutron Activation Analysis

    International Nuclear Information System (INIS)

    Elin Nuraini; Elisabeth; Sunardi

    2002-01-01

    Determination of substances content of soil surface using neutron activation analysis has been performed. The aim of this research is to determine whether there are any dangerous, hazardous and toxic substances that released from The Research and Development Center for Advanced Technology (RDCAT) as a government institution has possibility in releasing that substances to the environment by surface water, sewage or rain water that give any dangerous the environmental. The fast neutron activation analysis was used to analyze the type and concentration of substances qualitative and quantitatively. The quantitative analysis was performed using relative method. Samples were counted using NaI(TI) detector. The result showed that there are several substances such as Mn-55, Fe-56, P-31, Al-27. Zn,65 and Mg-24. And there are found any hazardous, dangerous and toxic substances in the samples that causing any danger to human and environment. (author)

  10. Fast neutron reactor core research at the C.E.A

    International Nuclear Information System (INIS)

    Chaudat, J.-P.

    1978-05-01

    This report covers all physical studies of fast neutron reactors carried out by the C.E.A., to povide basic data (multi-group cross sections) and computer methods which may be used to calculate nuclear power plant neutron properties with the precision required by the project. The approach adopted to establish the basic data used in all core calculations is described in greated detail: choice of a reference procedure for basic mode calculations (CARNAVAL set), choice of particular experimental programs to reduce uncertainties in connection with the formula set, adjustement of cross sections on integral parameters measured on critical experiments. The development of the formula set is closely connected with the project requirements; hence the set is modified with respect to the core characteristics of the power plant studied. Following an explanation of how the CARNAVAL III and IV formula sets -used for PHENIX and SUPER-PHENIX respectively- were derived, current studies for heterogeneous cores are described [fr

  11. Fast-neutron total and scattering cross sections of 103Rh

    International Nuclear Information System (INIS)

    Smith, A.B.; Guenther, P.T.; Whalen, J.F.

    1982-07-01

    Fast-neutron total cross sections of 103 Rh are measured with 30 to 50 keV resolutions from 0.7 to 4.5 MeV. Differential elastic- and inelastic-scattering cross sections are measured from 1.45 to 3.85 MeV. Scattered-neutron groups corresponding to excited levels at 334 +- 13, 536 +- 7, 648 +- 25, 796 +- 20, 864 +- 22, 1120 +- 22, 1279 +- 50, 1481 +- 27, 1683 +- 39, 1840 +- 79, 1991 +- 71 and 2050 (tentative) keV are observed. An optical-statistical model is derived from the elastic-scattering results. The experimental values are compared with comparable quantities given in the ENDF/B-V evaluation

  12. Radiative capture of fast neutrons by /sup 165/Ho and /sup 238/U

    Energy Technology Data Exchange (ETDEWEB)

    McDainels, D K; Varghese, P; Drake, D M; Arthur, E; Lindholm, A; Bergqvist, I; Krumlinde, J

    1982-04-01

    Radiative capture of fast neutrons by the deformed nuclei /sup 165/Ho and /sup 238/U was measured over the 7- to 15-MeV incident neutron energy range. The ..gamma..-ray detector was a large NaI(T1) anti-Compton spectrometer, and time-of-flight techniques were used to suppress background. The total radiative capture cross section exhibits an energy dependence that clearly indicates the importance of the direct-semidirect reaction mechanism. Theoretical calculations compare favorably with experimental observations. However, the shapes of the observed ..gamma..-ray spectra differ from those calculated, indicating problems in estimating the distribution of single-particle strength for these deformed nuclei.

  13. Large area imaging of hydrogenous materials using fast neutrons from a DD fusion generator

    International Nuclear Information System (INIS)

    Cremer, J.T.; Williams, D.L.; Gary, C.K.; Piestrup, M.A.; Faber, D.R.; Fuller, M.J.; Vainionpaa, J.H.; Apodaca, M.; Pantell, R.H.; Feinstein, J.

    2012-01-01

    A small-laboratory fast-neutron generator and a large area detector were used to image hydrogen-bearing materials. The overall image resolution of 2.5 mm was determined by a knife-edge measurement. Contact images of objects were obtained in 5–50 min exposures by placing them close to a plastic scintillator at distances of 1.5 to 3.2 m from the neutron source. The generator produces 10 9 n/s from the DD fusion reaction at a small target. The combination of the DD-fusion generator and electronic camera permits both small laboratory and field-portable imaging of hydrogen-rich materials embedded in high density materials.

  14. Status report on treatment planning with the fast neutron beam at Hamburg-Eppendorf

    International Nuclear Information System (INIS)

    Hess, A.; Schmidt, R.; Franke, H.D.

    1981-01-01

    For treatment planning with the fast neutron beam (DT, 14 MeV) at the Radiotherapy Department of the University Hospital Hamburg-Eppendorf the decrement line method is applied to compute isodose curves (total beam or neutrons and gamma-rays separately). The isodose curves are generated by a measured depth dose distribution and one lateral dose distribution at 10 cm phantom depth assuming two crossing points of the decrement lines at the edges of the collimator. By this method isodose charts have been generated for all available field sizes at 80 cm SSD. For the determination of depth dose values at different SSD a modified inverse square law has to be taken into account. Computerized treatment plans are calculated with the same technique used by the SIDOS-U1 (Siemens) planning system. (orig.)

  15. Contributions to the neutronic analysis of a gas-cooled fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    Martin-del-Campo, Cecilia, E-mail: cecilia.martin.del.campo@gmail.com [Departamento de Sistemas Energeticos, Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Paseo Cuauhnahuac 8532. Jiutepec, Morelos (Mexico); Reyes-Ramirez, Ricardo, E-mail: ricarera@yahoo.com.mx [Departamento de Sistemas Energeticos, Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Paseo Cuauhnahuac 8532. Jiutepec, Morelos (Mexico); Francois, Juan-Luis, E-mail: juan.luis.francois@gmail.com [Departamento de Sistemas Energeticos, Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Paseo Cuauhnahuac 8532. Jiutepec, Morelos (Mexico); Reinking-Cejudo, Arturo G., E-mail: reinking@servidor.unam.mx [Departamento de Sistemas Energeticos, Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Paseo Cuauhnahuac 8532. Jiutepec, Morelos (Mexico)

    2011-06-15

    Highlights: > Differences on reactivity with MCNPX and TRIPOLI-4 are negligible. > Fuel lattice and core criticality calculations were done. > A higher Doppler coefficient than coolant density coefficient. > Zirconium carbide is a better reflector than silicon carbide. > Adequate active height, radial size and reflector thickness were obtained. - Abstract: In this work the Monte Carlo codes MCNPX and TRIPOLI-4 were used to perform the criticality calculations of the fuel assembly and the core configuration of a gas-cooled fast reactor (GFR) concept, currently in development. The objective is to make contributions to the neutronic analysis of a gas-cooled fast reactor. In this study the fuel assembly is based on a hexagonal lattice of fuel-pins. The materials used are uranium and plutonium carbide as fuel, silicon carbide as cladding, and helium gas as coolant. Criticality calculations were done for a fuel assembly where the axial reflector thickness was varied in order to find the optimal thickness. In order to determine the best material to be used as a reflector, in the reactor core with neutrons of high energy spectrum, criticality calculations were done for three reflector materials: zirconium carbide, silicon carbide and natural uranium. It was found that the zirconium carbide provides the best neutron reflection. Criticality calculations using different active heights were done to determine the optimal height, and the reflector thickness was adjusted. Core criticality calculations were performed with different radius sizes to determine the active radial dimension of the core. A negative temperature coefficient of reactivity was verified for the fuel. The effect on reactivity produced by changes in the coolant density was also evaluated. We present the main neutronic characteristics of a preliminary fuel and core designs for the GFR concept. ENDF-VI cross-sections libraries were used in both the MCNPX and TRIPOLI-4 codes, and we verified that the obtained

  16. Determination of the fast neutrons spectra by the Elastic scattering method (n, p); Determinacion del espectro de neutrones rapidos por el metodo de la dispersion elastica (n, p)

    Energy Technology Data Exchange (ETDEWEB)

    Elizalde D, J

    1973-07-01

    This work consists in determining the fast neutron spectra emitted by a Pu-Be isotopic source. The implemented technique is based in the spectrometry (n, p). This consists in making to fall on a fast neutrons beams (polyenergetic) over a thin film of hydrogenated material, detecting the spectra of emitted protons at a fix angle. The polyethylene film and the used solid state detector are inside of a vacuum chamber. The detector is placed at 30 degree with respect to direction of the incident neutrons beam. The protons spectra is stored in a multichannel. the energy is obtained with the prior calibration of the system. The data processing involves the transformation of the protons spectra observed at the falling on neutrons spectra over the film. The energy of the neutrons is related with that of the protons, according to the collision kinematical equations. The cross section of elastic collision of the neutrons with the hydrogen atoms is obtained from literature. Applying these relations to the observed spectra it is obtained the falling on neutron spectra over the film. (Author)

  17. Fast diffusion in the intermetallics Ni3Sb and Fe3Si: a neutron scattering study

    International Nuclear Information System (INIS)

    Randl, O.G.

    1994-02-01

    We present the results of neutron scattering experiments designed to elucidate the reason for the extraordinarily fast majority component diffusion in two intermetallic alloys of DO 3 structure, Fe 3 Si and Ni 3 Sb: We have performed diffraction measurements in order to determine the crystal structure and the state of order of both alloys as a function of composition and temperature. The results on Fe 3 Si essentially confirm the classical phase diagram: The alloys of a composition between 16 and 25 at % Si are DO 3 -ordered at room temperature and disorder at high temperatures. The high-temperature phase Ni 3 Sb also crystallizes in the DO 3 structure. Vacancies are created in one Ni sublattice at Sb contents beyond 25 at %. In a second step the diffusion mechanism in Ni 3 Sb has been studied by means of quasielastic neutron scattering. The results are reconcileable with a very simple NN jump model between the two different Ni sublattices. Finally, the lattice dynamics of Fe 3 Si and Ni 3 Sb has been studied by inelastic neutron scattering in dependence of temperature (both alloys) and alloy composition (Fe 3 Si only). The results on Fe 3 Si indicate clearly that phonon enhancement is not the main reason for fast diffusion in this alloy. In Ni 3 Sb no typical signs of phonon-enhanced diffusion have been found either. As a conclusion, fast diffusion in DO 3 intermetallics is explained by extraordinarily high vacancy concentrations (several atomic percent) in the majority component sublattices. (author)

  18. A new Recoil Proton Telescope for energy and fluence measurement of fast neutron fields

    Energy Technology Data Exchange (ETDEWEB)

    Lebreton, Lena; Bachaalany, Mario [IRSN / LMDN (Institut de Radioprotection et de Surete nucleaire / Laboratoire de Metrologie et de dosimetrie des neutrons), Cadarache Bat.159, 13115 Saint Paul-lez-Durance, (France); Husson, Daniel; Higueret, Stephane [IPHC / RaMsEs (Institut Pluridisciplinaire Hubert Curien / Radioprotection et Mesures Environnementales), 23 rue du loess - BP28, 67037 Strasbourg cedex 2, (France)

    2015-07-01

    The spectrometer ATHENA (Accurate Telescope for High Energy Neutron metrology Applications), is being developed at the IRSN / LMDN (Institut de Radioprotection et de Surete nucleaire / Laboratoire de Metrologie et de dosimetrie des neutrons) and aims at characterizing energy and fluence of fast neutron fields. The detector is a Recoil Proton Telescope and measures neutron fields in the range of 5 to 20 MeV. This telescope is intended to become a primary standard for both energy and fluence measurements. The neutron detection is achieved by a polyethylene radiator for n-p conversion, three 50{sub m} thick silicon sensors that use CMOS technology for the proton tracking and a 3 mm thick silicon diode to measure the residual proton energy. This first prototype used CMOS sensors called MIMOSTAR, initially developed for heavy ion physics. The use of CMOS sensors and silicon diode increases the intrinsic efficiency of the detector by a factor of ten compared with conventional designs. The first prototype has already been done and was a successful study giving the results it offered in terms of energy and fluence measurements. For mono energetic beams going from 5 to 19 MeV, the telescope offered an energy resolution between 5 and 11% and fluence difference going from 5 to 7% compared to other home standards. A second and final prototype of the detector is being designed. It will hold upgraded CMOS sensors called FastPixN. These CMOS sensors are supposed to run 400 times faster than the older version and therefore give the telescope the ability to support neutron flux in the order of 107 to 108cm{sup 2}:s{sup 1}. The first prototypes results showed that a 50 m pixel size is enough for a precise scattering angle reconstruction. Simulations using MCNPX and GEANT4 are already in place for further improvements. A DeltaE diode will replace the third CMOS sensor and will be installed right before the silicon diode for a better recoil proton selection. The final prototype with

  19. Formulary for neutron propagation in sodium-steel media for the fast reactor shields

    International Nuclear Information System (INIS)

    Bouteau, F.; Caumette, P.; Khairallah, A.; Oceraies, Y.; Devillers, C.

    1975-01-01

    The simplified calculational tool (''formulary'') for neutron propagation in the shields of fast reactors, being developed at CEA, has two objectives: to reduce the cost of the major part of design calculations, without a significant loss of accuracy; to facilitate the adjustment of the calculational tool with the results of the program of integral propagation experiments, which is conducted in parallel with the development of the calculational method. The version 0 (i.e. before any adjustment) of the formulary and a first test of its validity as compared to the results of integral measurements are presented [fr

  20. N-acetylcysteine and captopril protect DNA and cells against radiolysis by fast neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Spotheim-Maurizot, M. (CNRS, 45 - Orleans (France). Centre de Biophysique Moleculaire); Garnier, F. (CNRS, 45 - Orleans (France). Centre de Biophysique Moleculaire); Kieda, C. (CNRS, 45 - Orleans (France). Centre de Biophysique Moleculaire); Sabattier, R. (Centre Hospitalier Regional d' Orleans, 45 (France). Service de Radiotherapie); Charlier, M. (CNRS, 45 - Orleans (France). Centre de Biophysique Moleculaire)

    1993-10-01

    N-Acetylcysteine and captopril, respectively mucolytic and antihypertensive drugs, contain free sulfhydryl groups. Since in general thiols have well-established radioprotective abilities, we sought putative radioprotective effects of these drugs against therapeutic fast neutrons. We show that pBR322 plasmid DNA is indeed protected against radiolytic strand breakage by both drugs. The oxygen independent protection is consistent with a hydroxyl radical scavenging mechanism. A clonogenicity assay reveals an increase of the survival of SCL-1 cultured keratinocytes irradiated in the presence of the drugs compared with cells irradiated without drugs. Our results suggest possible interferences between treatment with drugs bearing-SH groups and radiotherapy. (orig.)

  1. CERN-group conceptual design of a fast neutron operated high power energy amplifier

    International Nuclear Information System (INIS)

    Rubbia, C.; Rubio, J.A.; Buono, S.

    1997-01-01

    The practical feasibility of an Energy Amplifier (EA) with power and power density which are comparable to the ones of the present generation of large PWR is discussed in this paper. This is only possible with fast neutrons. Schemes are described which offer a high gain, a large maximum power density and an extended burn-up, well in excess of 100 GW x d/t corresponding to about five years at full power operation with no intervention on the fuel core. The following topics are discussed: physics considerations and parameter definition, the accelerator complex, the energy amplifier unit, computer simulated operation, and fuel cycle closing

  2. Fast neutron fluence evaluation of the smart reactor pressure vessel by using the GEOSHIELD code

    International Nuclear Information System (INIS)

    Kim, K.Y.; Kim, K.S.; Kim, H.Y.; Lee, C.C.; Zee, S.Q.

    2007-01-01

    In Korea, the design of an advanced integral reactor system called SMART has been developed by KAERI to supply energy for seawater desalination as well as an electricity generation. A fast neutron fluence distribution at the SMART reactor pressure vessel was evaluated to confirm the integrity of the vessel by using the GEOSHIELD code. The GEOSHIELD code was developed by KAERI in order to prepare an input list including a geometry modeling of the DORT code and to process results from the DORT code output list. Results by a GEOSHIELD code processing and by a manual processing of the DORT show a good agreement. (author)

  3. Fast neutron radiography scanner for the detection of contraband in air cargo containers

    International Nuclear Information System (INIS)

    Eberhardt, J.E.; Rainey, S.; Stevens, R.J.; Sowerby, B.D.; Tickner, J.R.

    2005-01-01

    There is a growing need to rapidly scan bulk air cargo for contraband such as illicit drugs and explosives. The Commonwealth Science and Industrial Research Organisation (CSIRO) have been working with Australian Customs Service to develop a scanner capable of directly scanning airfreight containers in 1-2 minutes without unpacking. The scanner combines fast neutron and gamma-ray radiography to provide high-resolution images that include information on material composition. A full-scale prototype scanner has been successfully tested in the laboratory and a commercial-scale scanner is due to be installed at Brisbane airport in 2005

  4. Quasielastic Diffuse Neutron Scattering from Fluorites in the Fast Ion Phase

    DEFF Research Database (Denmark)

    Clausen, K.; Hayes, W.; Hutchings, M.T

    1981-01-01

    Quasielastic diffuse coherent neutron scattering arising from the dynamically disordered anions in CaF2 and PbF2 has been investigated as the temperature is increased into the fast ion phase. The characteristic variation with scattering vector Image of the integrated intensity, S(Image ), can...... be accounted for by a model in which the most probable instantaneous configuration of the defective anions is a cluster centered at the mid-point of nearest-neighbour regular anion sites. The observed S(Image ,ω) is Lorentzian in ω and the width has a marked increase with temperature....

  5. Conceptual design for a fast neutron ionization chamber for fusion reactor plasma diagnostics

    International Nuclear Information System (INIS)

    Sailor, W.C.; Barnes, C.W.

    1994-01-01

    A conceptual design for a radiation-hard ''pointing'' fast neutron ionization chamber that is capable of delivering a 1 MHz countrate of T(D,n) events at ITER is given. The detector will use a ∼1 cm 3 volume of CO 2 fill gas at 0.1 bar pressure in a 500 V/cm electric field. The pulse widths will be ∼10 ns, enabling it to operate in a flux of ∼ 6 x 10 13 DT n/cm 2 /sec. A special collimator design is used, giving an estimated angular resolution of 4.5 degrees HWHM

  6. Conceptual design for a fast neutron ionization chamber for fusion reactor plasma diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Sailor, W.C.; Barnes, C.W.

    1994-06-01

    A conceptual design for a radiation-hard ``pointing`` fast neutron ionization chamber that is capable of delivering a 1 MHz countrate of T(D,n) events at ITER is given. The detector will use a {approximately}1 cm{sup 3} volume of CO{sub 2} fill gas at 0.1 bar pressure in a 500 V/cm electric field. The pulse widths will be {approximately}10 ns, enabling it to operate in a flux of {approximately} 6 {times} 10{sup 13} DT n/cm{sup 2}/sec. A special collimator design is used, giving an estimated angular resolution of 4.5 degrees HWHM.

  7. Chemical etching studies of a Brazilian polycarbonate to fast neutron detection

    Energy Technology Data Exchange (ETDEWEB)

    Souto, E.B.; Campos, L.L. [Instituto de Pesquisas Energeticas e Nucleares, IPEN- CNEN/SP Radiation Metrology Center (CMR) Av. Prof. Lineu Prestes, 2242 CEP: 05508-000 Sao Paulo - SP (Brazil)]. e-mail: ebsouto@ipen.br

    2006-07-01

    The Dosimetric Materials Laboratory (LMD) of the Radiation Metrology Center (CMR) is developing a personal dosimeter for fast neutrons using the technique of solid state nuclear track detectors (SSNTD). This technique is based on the recorded damage (tracks) in dielectric materials due to the impact of charged particles. The tracks are revealed and amplified for visualization in optic microscope through a technique known as chemical etching. The LMD is investigating a Brazilian commercial polycarbonate as a new passive fast neutron's detector in substitution to the traditional materials, as the cellulose nitrate LR-115 and the polycarbonates Makrofol and CR-39. The variation of the etching parameters (chemical solution, time and temperature) alters the response of the material; the best revelation conditions provide the best relationship among the amount of revealed tracks, their clearness and the time spent for this. The polycarbonate studied is a resin of same chemical monomer of Makrofol (C,6H,403). Samples of 3 x 1 cm{sup 2} of the polycarbonate were irradiated with 5 mSv of fast neutrons ({sup 241}Am-Be) and revealed with the chemical solution PEW-40 (15% KOH, 45% H{sub 2}O, 40% C{sub 2}H{sub 5}OH), commonly used for Makrofol. The studied etching parameters were time and temperature. Groups of four samples were revealed at temperatures of 50, 65, 75, 90 and 100 C with etching times varying from one to six hours. The used track's counting procedure was that referred in the literature. The best response to fast neutrons was obtained at 75 C; in spite of their similar answers, smaller temperatures join larger uncertainties in the track's counting and poorer clearness. At this temperature, the number of revealed tracks increases with the etching time approximately until a plateau at three hours. For etching times higher than four hours the polycarbonate presents overlap of tracks. If the temperature is adjusted to 75 C, the etching time should be in

  8. Improvement to surface lagging systems in a nuclear reactor, particularly of the fast neutron type

    International Nuclear Information System (INIS)

    Lemercier, Guy.

    1979-01-01

    Improvements to surface lagging systems in a nuclear reactor, particularly of the fast neutron kind. This system is composed of an assembly of panels each formed of a stack of metal fabric or trellis held against the surface to be protected, by a double fixing system comprising (a) a tubular component passing through a hole in the panel and applying it against the surface through a bearing plate, and (b) a bolt fitted in the centre of the tubular component, also secured to the surface and holding a washer capable of preventing the fall of the tubular component and the panel should the tubular component fracture [fr

  9. Aquelarre. A computer code for fast neutron cross sections from the statistical model

    International Nuclear Information System (INIS)

    Guasp, J.

    1974-01-01

    A Fortran V computer code for Univac 1108/6 using the partial statistical (or compound nucleus) model is described. The code calculates fast neutron cross sections for the (n, n'), (n, p), (n, d) and (n, α reactions and the angular distributions and Legendre moments.for the (n, n) and (n, n') processes in heavy and intermediate spherical nuclei. A local Optical Model with spin-orbit interaction for each level is employed, allowing for the width fluctuation and Moldauer corrections, as well as the inclusion of discrete and continuous levels. (Author) 67 refs

  10. Investigation of Lecturer's Chalk by x-ray Florescence and Fast Neutron Activation Techniques

    International Nuclear Information System (INIS)

    Hassan, M.F.

    2011-01-01

    Different samples of lecturer's chalk were studied, using X-ray florescence (XRF) and Fast Neutron Activation Analysis (FNAA) techniques to ensure the safety of its use. The K (X-rays) and the gamma-rays were measured, using Si(Li) and high-purity germanium (HPGe) spectrometers to detect and determine qualitatively and quantitatively the constituents of the studied samples. The concentrations of the elements (Ca and small traces of Al, Fe, Mg and Si) were measured and their presence was confirmed by gamma-ray, lifetime and/or XRF measurements.

  11. Elemental investigation of talcum baby powder by X-Ray florescence and fast neutron activation Techniques

    International Nuclear Information System (INIS)

    Hassan, M. F.; Abd El Wahab, M.; Nada, A.

    2008-01-01

    Different samples of Egyptian and Hungarian talcum powders were studied, using X-ray florescence (XRF) and Fast Neutron Activation Analysis (FNAA) techniques to ensure the safety of its use. The K (X-rays) and the gamma-rays were measured, using Si(Li) and high-purity germanium (HPGe) spectrometers to detect and determine qualitatively and quantitatively the constituents of the studied samples. The concentrations of the elements (Mg, Si, Al, Fe, Zn, and Ba) were measured and their presence was confirmed by X-ray, lifetime and/or XRF measurements. One of these samples was also studied, using the Environmental Scanning Electron Microscope (ESEM)

  12. Monte Carlo study in the mechanisms of transport of fast neutrons in various media

    International Nuclear Information System (INIS)

    Ku, L.

    1976-01-01

    The life histories of fast neutrons created by the straight Monte Carlo method in various attenuation media were examined. The media studied range from the one with simple, featureless properties (Na) to iron with very complicated cross section structure. The life histories of exceptional neutrons, i.e. those staying very close to the source, or those going very far from the source, were compared with those of the general population. When the exceptional neutrons exploited a particular collision property in a narrow energy band in order to reach a given detector, the method of analyzing Monte Carlo histories was able to provide a clear physical picture and single out the influence of that property on the macroscopic behavior of the neutrons. Two such phenomena were demonstrated by using this technique. In one, transport in a cross section minimum dominates the deep penetration of the neutrons. In such a circumstance most of the spatial transport is accomplished by the traveling at energies in and near the minimum, while little transport occurs at any other energies. The second example involves the effect of inelastic scattering on the low-energy leakage spectra for small bare assemblies. It is shown that, for a small bare iron sphere and for a fission source, the exit current spectrum below 100 keV is extremely sensitive to the details of the inelastic scattering near threshold. It often happened that in some exceptional situations the number of histories available for the analysis was too few to give statistically significant results. The most important conclusion to be drawn here is that the analysis of Monte Carlo histories can provide information on the details of transport mechanisms that is not available through forward or even adjoint deterministic transport calculations. 47 figures, 21 tables

  13. NEUTRON CROSS SECTION EVALUATIONS OF FISSION PRODUCTS BELOW THE FAST ENERGY REGION

    Energy Technology Data Exchange (ETDEWEB)

    OH,S.Y.; CHANG,J.; MUGHABGHAB,S.

    2000-05-11

    Neutron cross section evaluations of the fission-product isotopes, {sup 95}Mo, {sup 99}Tc, {sup 101}Ru, {sup 103}Rh, {sup 105}Pd, {sup 109}Ag, {sup 131}Xe, {sup 133}Cs, {sup 141}Pr, {sup 141}Nd, {sup 147}Sm, {sup 149}Sm, {sup 150}Sm, {sup 151}Sm, {sup 152}Sm, {sup 153}Eu, {sup 155}Gd, and {sup 157}Gd were carried out below the fast neutron energy region within the framework of the BNL-KAERI international collaboration. In the thermal energy region, the energy dependence of the various cross-sections was calculated by applying the multi-level Breit-Wigner formalism. In particular, the strong energy dependence of the coherent scattering lengths of {sup 155}Gd and {sup 157}Gd were determined and were compared with recent calculations of Lynn and Seeger. In the resonance region, the recommended resonance parameters, reported in the BNL compilation, were updated by considering resonance parameter information published in the literature since 1981. The s-wave and, if available, p-wave reduced neutron widths were analyzed in terms of the Porter-Thomas distribution to determine the average level spacings and the neutron strength functions. Average radiative widths were also calculated from measured values of resolved energy resonances. The average resonance parameters determined in this study were compared with those in the BNL and other compilations, as well as the ENDF/B-VI, JEF-2.2, and JENDL-3.2 data libraries. The unresolved capture cross sections of these isotopes, computed with the determined average resonance parameters, were compared with measurements, as well as the ENDF/B-VI evaluations. To achieve agreement with the measurements, in a few cases minor adjustments in the average resonance parameters were made. Because of astrophysical interest, the Maxwellian capture cross sections of these nuclides at a neutron temperature of 30 keV were computed and were compared with other compilations and evaluations.

  14. Study of the production of neutron-rich isotope beams issuing from fissions induced by fast neutrons; Etude de la production de faisceaux riches en neutrons par fission induite par neutrons rapides

    Energy Technology Data Exchange (ETDEWEB)

    Lau, Ch

    2000-09-15

    This work is a contribution to the PARRNe project (production of radioactive neutron-rich isotopes). This project is based on the fission fragments coming from the fission of 238-uranium induced by fast neutrons. The fast neutron flux is produced by the collisions of deutons in a converter. Thick targets of uranium carbide and liquid uranium targets have been designed in order to allow a quick release of fission fragments. A device, able to trap on a cryogenic thimble rare gas released by the target, has allowed the production of radioactive nuclei whose half-life is about 1 second. This installation has been settled to different deuton accelerators in the framework of the European collaboration SPIRAL-2. A calibration experiment has proved the feasibility of fixing an ISOL-type isotope separator to a 15 MV tandem accelerator, this installation can provide 500 nA deutons beams whose energy is 26 MeV and be a valuable tool for studying fast-neutron induced fission. Zinc, krypton, rubidium, cadmium, iodine, xenon and cesium beams have been produced in this installation. The most intense beams reach 10000 nuclei by micro-coulomb for 26 MeV deutons. An extra gain of 2 magnitude orders can be obtained by using a more specific ion source and by increasing the thickness of the target. Another extra gain of 2 magnitude orders involves 100 MeV deutons.

  15. Microdosimetric studies using a Filtered Fast Neutron Irradiation System of research reactor to application in radiation biology

    International Nuclear Information System (INIS)

    Rodrigues, Pedro Pereira

    2007-01-01

    In this work, microdosimetric measurements were performed using a Wall-less Tissue Equivalent Proportional Counter - TEPC with spherical cavity with an inner diameter of 1.27 cm. The TEPC was tilled with pure propane gas, C 3 H 8 at 5.6 kPa (42 Torr) pressure, which is equivalent to 1.3 μm in diameter of unit density tissue. The microdosimetric measurement device was irradiated with fast neutron radiation from Texas A and M University Nuclear Science Center research reactor, in College Station, Texas. The fast neutron beams were emitted with three different power values, 0.5, 1.0 and 2.0 kW. during 1h for both high gain and low gain, totalizing two hours for each power with 0.0083 Gy/min of dose rate. The neutron was filtered using the heavily filtered fast neutron irradiation system (FNIS). from Nuclear Science Center, to obtain a decrease of neutron radiation contamination by gamma ray and so, to gain the neutron microdosimetric spectra as. frequency distribution of lineal energy, dose distribution of lineal energy with good precision, and another quantities as frequency-mean of lineal energy, dose- mean of lineal energy, absorbed dose, equivalent dose and average quality factor of fast neutron. The obtained results were satisfactory, with the neutron microdosimetric spectra showing a gamma ray contamination under 5 %, especially to dose distribution of lineal energy. The results obtained in this work were in agreement when compared with another results from scientific literature, which used another procedure to reduce the neutron contamination by gamma ray. (author)

  16. A re-sequencing based assessment of genomic heterogeneity and fast neutron-induced deletions in a common bean cultivar

    Directory of Open Access Journals (Sweden)

    Jamie A. O'Rourke

    2013-06-01

    Full Text Available A small fast neutron mutant population has been established from Phaseolus vulgaris cv. Red Hawk. We leveraged the available P. vulgaris genome sequence and high throughput next generation DNA sequencing to examine the genomic structure of five Phaseolus vulgaris cv. Red Hawk fast neutron mutants with striking visual phenotypes. Analysis of these genomes identified three classes of structural variation; between cultivar variation, natural variation within the fast neutron mutant population, and fast neutron induced mutagenesis. Our analyses focused on the latter two classes. We identified 23 large deletions (>40 bp common to multiple individuals, illustrating residual heterogeneity and regions of structural variation within the common bean cv. Red Hawk. An additional 18 large deletions were identified in individual mutant plants. These deletions, ranging in size from 40 bp to 43,000 bp, are potentially the result of fast neutron mutagenesis. Six of the 18 deletions lie near or within gene coding regions, identifying potential candidate genes causing the mutant phenotype.

  17. Simulating irradiation hardening in tungsten under fast neutron irradiation including Re production by transmutation

    Science.gov (United States)

    Huang, Chen-Hsi; Gilbert, Mark R.; Marian, Jaime

    2018-02-01

    Simulations of neutron damage under fusion energy conditions must capture the effects of transmutation, both in terms of accurate chemical inventory buildup as well as the physics of the interactions between transmutation elements and irradiation defect clusters. In this work, we integrate neutronics, primary damage calculations, molecular dynamics results, Re transmutation calculations, and stochastic cluster dynamics simulations to study neutron damage in single-crystal tungsten to mimic divertor materials. To gauge the accuracy and validity of the simulations, we first study the material response under experimental conditions at the JOYO fast reactor in Japan and the High Flux Isotope Reactor at Oak Ridge National Laboratory, for which measurements of cluster densities and hardening levels up to 2 dpa exist. We then provide calculations under expected DEMO fusion conditions. Several key mechanisms involving Re atoms and defect clusters are found to govern the accumulation of irradiation damage in each case. We use established correlations to translate damage accumulation into hardening increases and compare our results to the experimental measurements. We find hardening increases in excess of 5000 MPa in all cases, which casts doubts about the integrity of W-based materials under long-term fusion exposure.

  18. Absorption and photoluminescence study of Al 2O 3 single crystal irradiated with fast neutrons

    Science.gov (United States)

    Izerrouken, M.; Benyahia, T.

    2010-10-01

    Colour centers formation in Al 2O 3 by reactor neutrons were investigated by optical measurements (absorption and photoluminescence). The irradiation's were performed at 40 °C, up to fast neutron ( E n > 1.2 MeV) fluence of 1.4 × 10 18 n cm -2. After irradiation the coloration of the sample increases with the neutron fluence and absorption band at about 203, 255, 300, 357 and 450 nm appear in the UV-visible spectrum. The evolution of each absorption bands as a function of fluence and annealing temperature is presented and discussed. The results indicate that at higher fluence and above 350 °C the F + center starts to aggregate to F center clusters (F 2, F 2+ and F22+). These aggregates disappear completely above 650 °C whereas the F and F + centers persist even after annealing at 900 °C. It is clear also from the results that the absorption band at 300 nm is due to the contribution of both F 2 center and interstitial Ali+ ions.

  19. Commissioning of the IDS Neutron Detector and $\\beta$-decay fast-timing studies at IDS

    CERN Document Server

    Piersa, Monika

    2016-01-01

    The following report describes my scientific activities performed during the Summer Student Programme at ISOLDE. The main part of my project was focused on commissioning the neutron detector dedicated to nuclear decay studies at ISOLDE Decay Station (IDS). I have participated in all the steps needed to make it operational for the IS609 experiment. In the testing phase, we obtained expected detector response and calibrations confirmed its successful commissioning. The detector was mounted in the desired geometry at IDS and used in measurements of the beta-delayed neutron emission of $^8$He. After completing aforementioned part of my project, I became familiar with the fast-timing method. This technique was applied at IDS in the IS610 experiment performed in June 2016 to explore the structure of neutron-rich $^{130-134}$Sn nuclei. Since the main part of my PhD studies will be the analysis of data collected in this experiment, the second part of my project was dedicated to acquiring knowledge about technical de...

  20. The effect of the imaging geometry and the impact of neutron scatter on the detection of small features in accelerator-based fast neutron radiography

    International Nuclear Information System (INIS)

    Ambrosi, R.M.; Watterson, J.I.W.

    2004-01-01

    In fast neutron radiography, the neutron energy spectrum, the imaging geometry, neutron scattering and the position-sensitive detector influence the feature contrast, resolution and the signal-to-noise ratio in the image. The effect of the imaging geometry can be explored by using a ray-tracing method. This requires following the path of neutrons through the imaging field, which includes the sample of interest. A relationship between imaging geometry and feature detectability can be developed. There are several important physical processes that govern image formation in fast neutron radiography. These are often examined individually in order to develop an understanding of how they affect the detectability of a feature in a radiograph; however, their combined effect is required to develop a model that can be regarded as a benchmark for future applications. In order to accomplish this, diverse techniques and tools are used. In this study it was expected that the ray-tracing experiments would show that changes in the imaging geometry would greatly affect the detectability of small features as a result of a loss in the resolution and indirectly the contrast. The effect of neutron scatter on the detectability of small features was taken into consideration by using Monte Carlo code MCNP-4A

  1. Cell inactivation and chromosomal aberrations induced by X-rays and fast neutrons in cells of the Chinese hamster. 1

    International Nuclear Information System (INIS)

    Tolkendorf, E.

    1979-01-01

    Asynchronously grown cultures of Chinese hamster cells V79-4 were irradiated in suspension with 180 kV X-rays and fast neutrons (average energy of 6.2 MeV). The damage was assessed by measuring cell survival and frequencies of chromosome aberrations in the first post-irradiation metaphases. The experimental data for survival and chromosome aberrations were fitted by computer programmes. From the fitted curves the relative biological effectiveness (RBE) of fast neutrons was calculated. The RBE shows a similar dose dependence for killed and aberrant cells. The RBE decreases with increasing dose and amounts to approximately 5 for both effects for small neutron doses. The highest RBE is found for asymmetrical chromosomal exchanges and is dependent on the neutron dose, too. However, for isochromatid deletions the RBE is dose independent with a value of 3.6. (author)

  2. Application of fast neutron radiography to three-dimensional visualization of steady two-phase flow in a rod bundle

    CERN Document Server

    Takenaka, N; Fujii, T; Mizubata, M; Yoshii, K

    1999-01-01

    Three-dimensional void fraction distribution of air-water two-phase flow in a 4x4 rod-bundle near a spacer was visualized by fast neutron radiography using a CT method. One-dimensional cross sectional averaged void fraction distribution was also calculated. The behaviors of low void fraction (thick water) two-phase flow in the rod bundle around the spacer were clearly visualized. It was shown that the void fraction distributions were visualized with a quality similar to those by thermal neutron radiography for low void fraction two-phase flow which is difficult to visualize by thermal neutron radiography. It is concluded that the fast neutron radiography is efficiently applicable to two-phase flow studies.

  3. Aspects of the physics and chemistry of water radiolysis by fast neutrons and fast electrons in nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    McCracken, D.R. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Tsang, K.T. [Atomic Energy of Canada Limited, Mississauga, Ontario (Canada); Laughton, P.J

    1998-09-01

    Detailed radiation physics calculations of energy deposition have been done for the coolant of CANDU reactors and Pressurized Water Reactors (PWRs). The geometry of the CANDU fuel channel was modelled in detail. Fluxes and energy-deposition rates for neutrons, recoil ions, photons, and fast electrons have been calculated using MCNP4B, WIMS-AECL, and specifically derived energy-transfer factors. These factors generate the energy/flux spectra of recoil ions from fast-neutron energy/flux spectra. The energy spectrum was divided into 89 discrete ranges (energy bins).The production of oxidizing species and net coolant radiolysis can be suppressed by the addition of hydrogen to the coolant of nuclear reactors. It is argued that the net dissociation of coolant by gamma rays is suppressed by lower levels of excess hydrogen than when dissociation is by ion recoils. This has consequences for the modelling of coolant radiolysis by homogeneous kinetics. More added hydrogen is required to stop water radiolysis by recoil ions acting alone than if recoil ions and gamma rays acted concurrently in space and time. Homogeneous kinetic models and experimental data suggest that track overlap is very inefficient in providing radicals from gamma-ray tracks to recombine molecular products in ion-recoil tracks. An inhomogeneous chemical model is needed that incorporates ionizing-particle track structure and track overlap. Such a model does not yet exist, but a number of limiting cases using homogeneous kinetics are discussed. There are sufficient uncertainties and contradictions in the data relevant to the radiolysis of reactor coolant that the relatively high CHC's (critical hydrogen concentration) observed in NRU reactor experiments (compared to model predictions) may be explainable by errors in fundamental data and understanding of water radiolysis under reactor conditions. The radiation chemistry program at CRL has been focused to generate quantitative water-radiolysis data in a

  4. Effect of fast neutron irradiation upon the omega transformation process in zirconium--niobium alloys

    International Nuclear Information System (INIS)

    Bremer, B.W.

    1974-01-01

    The effect of fast neutrons (E greater than 1 MeV) upon the beta-omega transformation was investigated. Irradiation-produced vacancies promoted the omega transformation by migrating to the regions of high compressive stress associated with the one-dimensional omega embryos, thereby allowing rearrangement of the strain fields. This rearrangement allows the omega embryos to attain large sizes. Growth of these embryos is diffusion controlled. However, irradiation produced no increase in growth rate. It is concluded the vacancies are effectively trapped by these strain fields even at the aging temperature, 400 0 C. The omega hardening mechanism is shown to be related solely to lattice misfit, independent of irradiation, and to saturate when the magnitude of the strain causes a breakdown of the coherent interface, thereby creating one or two interfacial dislocations. Aging at 400 0 C results in alpha growth into the interomega beta phase, producing an additional hardness increase additive to that resulting from the omega phase. At higher aging temperatures 500 0 C, the omega is rapidly replaced by alpha. The alpha microstructure consists of ultra-fine grains, 1000 A, each composed of one 12 interrelated crystallographic variants. Fast neutron irradiation has no effect upon the omega metastable equilibrium phase diagram

  5. A case of malignant melanoma of the maxilla treated by adoptive immunotherapy after fast neutron therapy

    International Nuclear Information System (INIS)

    Morifuji, Masayo; Ohishi, Masamichi; Higuchi, Yoshinori; Ozeki, Satoru; Tashiro, Hideo

    1992-01-01

    A 77-year-old male patient with malignant melanoma was treated by fast neutron therapy and immunotherapy. Total dose of fast neutron applied to the primary lesion was 1905 cGy per 21 fractionation for 46 days. For adoptive immunotherapy, lymphocytes were collected from the peripheral blood drawn from the patient 2 days after the injection of cyclophosphamide. T cells were further purified by passing the lymphocytes through nylon wool. Cytotoxic T cells were induced by incubating the T cells mixed with allogeneic malignant melanoma cells and a small number of patient's adherent cells, and activated with recombinant interleukin-2 (γ IL-2). Our patient and the patient from whom stimulating melanoma cells were derived shared A locous 24 and B locous 51 of MHC class I antigens in common. Thus prepared cytotoxic T cells were inoculated to the patient via the maxillary artery, 3 to 4 times a week for one month. Total amount of cells transferred was 5.6 x 10 8 (97% lymphocytes). Primary lesion reduced markedly by the therapies. During adoptive immunotherapy, increase in natural killer cells and decrease in both suppressor/inducer T-cells and macrophages were observed. However, lung metastases appeared 3 months after adoptive immunotherapy. While the nonspecific immunotherapy (OK-432 injection) was being conducted thereafter, growth of the metastatic lesions of the lung was kept gentle but became obvious after the suspension of the treatment. (author)

  6. Biological effects and RAPD analysis of alfalfa (medicago sativa L.) irradiated by fast neutrons

    International Nuclear Information System (INIS)

    Han Weibo; Zhang Yuexue; Tang Fenglan; Liu Jielin; Liu Fengqi; Shang Chen; Kong Fuquan; Wang Xiao; Liu Luxiang

    2011-01-01

    Dry seeds of alfalfa variety Zhaodong were irradiated by fast neutrons generated by linear accelerator with three fluences, 3.60 × 10 11 , 7.10 × 10 11 and 3.54 × 10 12 /cm 2 respectively. Seed germination, growth, and RAPD analysis on the mutation were reported in this study. The results showed that germination vigor and germination rate of irradiated seeds were higher than those of control, but seedling height and root length were reduced with the increase of fluences. When the dosages reached 3.54 × 10 12 /cm 2 , seedling root length decreased by 81.63% compared with the control, but the seedling didn't grow any true leaves except for cotyledon. 36 primers were used in RAPD analysis, and the results showed that the RAPD polymorphic loci rate was 7.25%, 6.52% and 5.80% among the 3.60 × 10 11 /cm 2 , 7.10 × 10 11 /cm 2 and 3.54 × 10 12 /cm 2 treated M 1 plants. RAPD polymorphic loci rate in the 3.60 × 10 11 /cm 2 treated plants was the highest among three treatment. It is concluded that 3.60 × 10 11 /cm 2 could be on optimum fluences for a alfalfa mutation by fast neutrons. (authors)

  7. Fast neutron relaxation length in concretes in the range of neutron energies En=0.5 - 17.5 MeV

    International Nuclear Information System (INIS)

    Desdin, L.F.; Garcia, L.; Perez, G.; Hernandez, A.; Herrera, E.; Tellez, E.

    1998-01-01

    In the present research were determined the fast neutron relaxation length y in different type of concretes, having special interest for biological shielding as well as for ordinary construction purposes, in the energy interval of 0.5-17.5 MeV. The values of Y concrete are reported with an accuracy of 6 %

  8. Fast Neutron Radiotherapy for Locally Advanced Prostate Cancer: Results of an RTOG Randomized Study

    Energy Technology Data Exchange (ETDEWEB)

    Laramore, George E. [Washington U.; Krall, John M. [Unlisted, PA; Thomas, Frank J. [Unlisted, OH; Griffin, Thomas W. [Washington U.; Maor, Moshe H. [Unlisted, TX; Hendrickson, Frank R. [Fermilab

    1985-01-01

    Between June 1977 and April 1983, the Radiation Therapy Oncology Group (RTOG) sponsored a Phase III randomized study investigating fast neutron radiation therapy in the treatment of patients with locally advanced (Stage C and D1) adenocarcinoma of the prostate gland. Patients were randomized to receive either conventional photon radiation therapy or fast neutron irradiation used in a mixed-beam treatment schedule (neutron/photon). A total of 91 analyzable patients were entered in the study; 78 of them were treated without major protocol deviations. The two treatment groups were balanced in regard to all major prognostic variables. Actuarial curves for "overall" survival, "determinantal" survival and local/regional control are presented both for the entire group of 91 patients and the 78 patients treated within protocol guidelines. The overall local/regional tumor recurrence rate is 7% for the mixed-beam treated group of patients and is 22% for the photon (X ray) treated group of patients. The difference is statistically significant at the p = 0.05 level. For the entire group of 91 evaluable patients, the 5-year "overall" survival rate is 62% for the mixed-beam-treated group and 35% for the photon-treated group. This difference is also statistically significant (p less than 0.05). However, this statistical significance is lost when the smaller number of patients treated strictly within protocol guidelines is considered. The significance is regained (p less than 0.02) when one looks at "determinantal" survival, which uses active cancer at time of death as the failure endpoint. This study demonstrates that a regional treatment modality, in this case mixed-beam irradiation, can influence both local/regional tumor control and survival in patients with locally-advanced adenocarcinoma of the prostate gland.

  9. Structural modification of aluminium oxynitride phases under stresses at high temperatures, high pressures and under irradiation by fast neutrons

    International Nuclear Information System (INIS)

    Labbe, J.C.; Jeanne, A.; Roult, G.

    1990-01-01

    The structural modifications of the aluminium oxynitride phases under stresses are studied by the time of flight neutron diffraction method, at high temperatures (up to 1375degC), at high pressures (up to 2.4 GPa), and under irradiation by fast neutrons (up to 3.2 X 10 20 n/cm 2 ). In each case the evolutions of cell parameter, interatomic bond angles, bond lengths and atomic positions are given. (orig.)

  10. Influence of gamma radiation and fast neutrons on the growth of Haplopappus gracilis (Nutt) A. Gray callus

    International Nuclear Information System (INIS)

    Cebulska-Wasilewska, A.; Wajda, L.; Korzonek, M.; Polska Akademia Nauk, Krakow. Inst. Fizjologii Roslin)

    1979-01-01

    The sensitivity of the callus of Haplopappus gracilis to gamma radiation and fast neutrons was studied. High doses of radiation cause inhibition of callus growth. At small doses the effect is less pronounced. Stimulation of callus growth was seen. Apart from morphological changes, ionizing radiations lowered the fresh weight ratio of the callus. The RBE value for 5.5 MeV neutrons depended on the dose rate of radiation and the combination of growth medium. (author)

  11. Fast neutron response of LiF T.L. dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Ranogajec-Komor, M.; Knezevic, I.; Miljanic, S.; Blagus, S. [Institute, Zagreb (Croatia)

    2006-07-01

    Generally, the intensity of the main dosimetric peak i.e. the sensitivity of the most thermoluminescence (T.L.) dosimeters (expressed as the T.L. response/absorbed dose) decreases with increasing Let. However, it is known that the 'high temperature peak' (H.T.P.) of LiF:Mg,Ti T.L. detectors increases with increasing Let, while the 'low temperature peak' (L.T.P.) of LiF:Mg,Ti decreases. H.T.P., also called peak 7, appears between 240- 270 Celsius degrees, while L.T.P. can be found in the literature as peak 5 or 'dosimetric' peak and appears in the temperature range 180 -240 Celsius degrees. The dose response results of L.T.P. and H.T.P. of LiF:Mg,Ti in the literature are ambiguous in high Let radiation field. The reason in most cases is that the gamma component in the mixed field is not taken properly into consideration. In the every day practice work place monitoring it is necessary to measure low Let (gamma) and both low and high Let (e.g. gamma-neutron) radiation in the mixed fields. T.L.D. -100 (Harshaw) and M.T.S.-N (Poland) LiF:Mg,Ti dosimeters produced from natural LiF are easily available and widely used in the practical dosimetry tasks. The aim of this study was to compare the Let sensitivity of L.T.P. and H.T.P. for T.L.D.-100 (Harshaw) and M.T.S.-N (Poland) LiF detectors for 14.5 MeV neutrons in the dose range 50 mGy-300 mGy (expressed in tissue kerma). At the same time the effect of the holder type to the dosimeter response was also studied. 14.5 MeV fast neutrons produced by Texas Nuclear Corporation 300 keV electrostatic accelerator using 3 H(d,n)4 He nuclear reaction was used for neutron irradiation. The gamma component in the mixed field was measured by Geiger-Mueller counter calibrated in standard dosimetry laboratory. Gamma irradiation was carried out by {sup 137}Cs source. It was found, that while the gamma sensitivity of M.T.S. -N compared to T.L.D.-100 is about 2.5, the fast neutron sensitivity is much lower

  12. Evidence of creation of Cm-242 in the oxide fuel of the fast neutron technology from measurements of neutron emission on Rapsodie needles

    International Nuclear Information System (INIS)

    Dulieu, Pierre; Sonnet, Alain; Guelf, Andre; Hayet, Lucien

    1969-06-01

    This study aimed at experimentally checking that estimated orders of magnitude of Cm 242 in fast neutron reactors correspond to the reality. Experiments have been performed on Rapsodie needles with a Fortissimo PuO 2 sample. They are complemented by a set of more precise measurements performed in Cadarache on Rapsodie assemblies. The influence of the spectrum of emitted neutrons on measurement is also studied. The authors describe how the fuel evolution and neutron emission evolution are calculated. They describe the performed experiments. They discuss how data are compiled (source axial variation, influence of Rapsodie operation diagram, influence of neutron spectrum, influence of fuel initial status, choice of cross sections, other factors). They present, discuss and interpret the obtained results [fr

  13. Calculations of the thermal and fast neutron fluxes in the Syrian miniature neutron source reactor using the MCNP-4C code.

    Science.gov (United States)

    Khattab, K; Sulieman, I

    2009-04-01

    The MCNP-4C code, based on the probabilistic approach, was used to model the 3D configuration of the core of the Syrian miniature neutron source reactor (MNSR). The continuous energy neutron cross sections from the ENDF/B-VI library were used to calculate the thermal and fast neutron fluxes in the inner and outer irradiation sites of MNSR. The thermal fluxes in the MNSR inner irradiation sites were also measured experimentally by the multiple foil activation method ((197)Au (n, gamma) (198)Au and (59)Co (n, gamma) (60)Co). The foils were irradiated simultaneously in each of the five MNSR inner irradiation sites to measure the thermal neutron flux and the epithermal index in each site. The calculated and measured results agree well.

  14. Simulation and prototyping of 2 m long resistive plate chambers for detection of fast neutrons and multi-neutron event identification

    Energy Technology Data Exchange (ETDEWEB)

    Elekes, Z., E-mail: z.elekes@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Aumann, T. [GSI Helmholtzzentrumfür Schwerionenforschung, Darmstadt (Germany); Technische Universität Darmstadt, Darmstadt (Germany); Bemmerer, D. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Boretzky, K. [GSI Helmholtzzentrumfür Schwerionenforschung, Darmstadt (Germany); Caesar, C. [GSI Helmholtzzentrumfür Schwerionenforschung, Darmstadt (Germany); Technische Universität Darmstadt, Darmstadt (Germany); Cowan, T.C. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Technische Universität Dresden, Dresden (Germany); Hehner, J.; Heil, M. [GSI Helmholtzzentrumfür Schwerionenforschung, Darmstadt (Germany); Kempe, M. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Rossi, D. [GSI Helmholtzzentrumfür Schwerionenforschung, Darmstadt (Germany); Röder, M. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Technische Universität Dresden, Dresden (Germany); Simon, H. [GSI Helmholtzzentrumfür Schwerionenforschung, Darmstadt (Germany); Sobiella, M.; Stach, D. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Reinhardt, T. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Technische Universität Dresden, Dresden (Germany); Wagner, A.; Yakorev, D. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Zilges, A. [Universität zu Köln, Köln (Germany); Zuber, K. [Technische Universität Dresden, Dresden (Germany)

    2013-02-11

    Resistive plate chamber (RPC) prototypes of 2 m length were simulated and built. The experimental tests using a 31 MeV electron beam, discussed in details, showed an efficiency higher than 90% and an excellent time resolution of around σ=100ps. Furthermore, comprehensive simulations were performed by GEANT4 toolkit in order to study the possible use of these RPCs for fast neutron (200 MeV–1 GeV) detection and multi-neutron event identification. The validation of simulation parameters was carried out via a comparison to experimental data. A possible setup for invariant mass spectroscopy of multi-neutron emission is presented and the characteristics are discussed. The results show that the setup has a high detection efficiency. Its capability of determining the momentum of the outgoing neutrons and reconstructing the relative energy between the fragments from nuclear reactions is demonstrated for different scenarios.

  15. BNCT enhanced fast neutron therapy: in vitro studies for preparing a clinical trial at the Essen cyclotron

    International Nuclear Information System (INIS)

    Wittig, A.; Sauerwein, W.; Hideghety, K.; Poeller, F.; Pignol, J.P.; Mueller, W.

    2000-01-01

    At the University Hospital Essen a cyclotron producing d(14)+Be fast neutrons is used routinely for patient treatment. Fast neutrons have demonstrated their potential to sterilize glioblastoma but could not show a clinical benefit because of lethal damages to healthy brain. At depth, fast neutrons are thermalized allowing neutron capture reactions, which can be used to enhance the applied dose. A selective increase of the dose to the tumor cells by BNCT may offer a chance to an effective treatment. In order to prepare a clinical trial in vitro experiments were performed. MeWo cells were irradiated in a tissue equivalent phantom at a depth of 6.5 cm. 91% 10 B enriched BSH was used to generate BNC effects. For a total dose of 1 Gy the thermal fluence rate was 3.4x10 10 cm -2 . An amount of 960 ppm 10 B present in the cell medium during irradiation led to a reduction of the cell survival from 3.6% (neutron alone) to 0.2%. If the irradiation was performed after incubation of the cells in BSH, but in a medium without BSH the survival was 1.6%. The in vitro set up demonstrates the capacity of BSH to considerably increase the biological effects of the neutron irradiation and add arguments for the opening of a clinical trial. (author)

  16. Method and apparatus for logging well boreholes with gamma rays from the inelastic scattering of fast neutrons

    International Nuclear Information System (INIS)

    Culver, R.B.

    1976-01-01

    The objects of the invention are accomplished, broadly, by method and apparatus which perform a first measurement with a pulsed neutron source and a detector, which performs a second measurement with a steady state neutron source and a detector, and which provides a difference between the two measurements to indicate the gamma rays due to inelastic scattering of fast neutrons. In addition, energy discrimination provides spectral analysis of the detected gamma radiation whereby various ratio determinations can be made, including the correction of a carbon/oxygen ratio with a silicon/calcium ratio. (author)

  17. Comparative study on fast neutrons radiobiological effect on Chinese hamster cells in culture depending on regime of irradiation

    International Nuclear Information System (INIS)

    Elisova, T.V.; Feoktistova, T.P.; Stavrakova, N.M.

    1988-01-01

    Comparative study of regularities of fast neutron radiobiological effect on Chinese hamster cells in culture under pulse and statistic irradiation regimes that was estimated by reproductive death of cells and induced frequency of resistence mutations to 6-tioguanine is carried out. It is stated that with the dose rate increase approximately by 6 orders radiobiological efficiency of fast neutrons decreases. It is suggested that one of the causes of decreasing pulse irradiation efficiency are processes on radiation-chemical level. 9 refs.; 3 figs

  18. Effect of fast neutrons and gamma radiation on germination, pollen and ovule sterility and leaf variations in mung bean

    International Nuclear Information System (INIS)

    Avinash Chandra; Tewari, S.N.

    1978-01-01

    The seeds of mung bean (Phaseolus aureus Roxb.) varieties S-8 and Pusa Baisakhi were irradiated with 15, 30, 45 and 60 k rads of gamma-rays and 500, 1000, 2000 and 3000 rads of fast neutrons. The results showed that there is a gradual reduction in amount of germination of seeds, pollen and ovule fertility with increasing doses of both mutagens. These mutagens also cause leaf abnormalities such as unifoliate, bifoliate, trifoliate, tetrafoliate and pentafoliate. Both tetra and pentafoliate leaves observed on the same plant of S-8 variety under fast neutron irradiation appear to have been associated with enhanced luxuriance of the plant resulting in satisfactory pod formation. (author)

  19. Analysis of the scintillation mechanism in a pressurized 4He fast neutron detector using pulse shape fitting

    Directory of Open Access Journals (Sweden)

    R.P. Kelley

    2015-03-01

    Full Text Available An empirical investigation of the scintillation mechanism in a pressurized 4He gas fast neutron detector was conducted using pulse shape fitting. Scintillation signals from neutron interactions were measured and averaged to produce a single generic neutron pulse shape from both a 252Cf spontaneous fission source and a (d,d neutron generator. An expression for light output over time was then developed by treating the decay of helium excited states in the same manner as the decay of radioactive isotopes. This pulse shape expression was fitted to the measured neutron pulse shape using a least-squares optimization algorithm, allowing an empirical analysis of the mechanism of scintillation inside the 4He detector. A further understanding of this mechanism in the 4He detector will advance the use of this system as a neutron spectrometer. For 252Cf neutrons, the triplet and singlet time constants were found to be 970 ns and 686 ns, respectively. For neutrons from the (d,d generator, the time constants were found to be 884 ns and 636 ns. Differences were noted in the magnitude of these parameters compared to previously published data, however the general relationships were noted to be the same and checked with expected trends from theory. Of the excited helium states produced from a 252Cf neutron interaction, 76% were found to be born as triplet states, similar to the result from the neutron generator of 71%. The two sources yielded similar pulse shapes despite having very different neutron energy spectra, validating the robustness of the fits across various neutron energies.

  20. Fast Neutron Spectrum Potassium Worth for Space Power Reactor Design Validation

    Energy Technology Data Exchange (ETDEWEB)

    Bess, John D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Marshall, Margaret A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Briggs, J. Blair [Idaho National Lab. (INL), Idaho Falls, ID (United States); Tsiboulia, Anatoli [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rozhikhin, Yevgeniy [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mihalczo, John T. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    A variety of critical experiments were constructed of enriched uranium metal (oralloy ) during the 1960s and 1970s at the Oak Ridge Critical Experiments Facility (ORCEF) in support of criticality safety operations at the Y-12 Plant. The purposes of these experiments included the evaluation of storage, casting, and handling limits for the Y-12 Plant and providing data for verification of calculation methods and cross-sections for nuclear criticality safety applications. These included solid cylinders of various diameters, annuli of various inner and outer diameters, two and three interacting cylinders of various diameters, and graphite and polyethylene reflected cylinders and annuli. Of the hundreds of delayed critical experiments, one was performed that consisted of uranium metal annuli surrounding a potassium-filled, stainless steel can. The outer diameter of the annuli was approximately 13 inches (33.02 cm) with an inner diameter of 7 inches (17.78 cm). The diameter of the stainless steel can was 7 inches (17.78 cm). The critical height of the configurations was approximately 5.6 inches (14.224 cm). The uranium annulus consisted of multiple stacked rings, each with radial thicknesses of 1 inch (2.54 cm) and varying heights. A companion measurement was performed using empty stainless steel cans; the primary purpose of these experiments was to test the fast neutron cross sections of potassium as it was a candidate for coolant in some early space power reactor designs.The experimental measurements were performed on July 11, 1963, by J. T. Mihalczo and M. S. Wyatt (Ref. 1) with additional information in its corresponding logbook. Unreflected and unmoderated experiments with the same set of highly enriched uranium metal parts were performed at the Oak Ridge Critical Experiments Facility in the 1960s and are evaluated in the International Handbook for Evaluated Criticality Safety Benchmark Experiments (ICSBEP Handbook) with the identifier HEU MET FAST 051. Thin

  1. Fast neutron irradiation tests of flash memories used in space environment at the ISIS spallation neutron source

    Science.gov (United States)

    Andreani, C.; Senesi, R.; Paccagnella, A.; Bagatin, M.; Gerardin, S.; Cazzaniga, C.; Frost, C. D.; Picozza, P.; Gorini, G.; Mancini, R.; Sarno, M.

    2018-02-01

    This paper presents a neutron accelerated study of soft errors in advanced electronic devices used in space missions, i.e. Flash memories performed at the ChipIr and VESUVIO beam lines at the ISIS spallation neutron source. The two neutron beam lines are set up to mimic the space environment spectra and allow neutron irradiation tests on Flash memories in the neutron energy range above 10 MeV and up to 800 MeV. The ISIS neutron energy spectrum is similar to the one occurring in the atmospheric as well as in space and planetary environments, with intensity enhancements varying in the range 108- 10 9 and 106- 10 7 respectively. Such conditions are suitable for the characterization of the atmospheric, space and planetary neutron radiation environments, and are directly applicable for accelerated tests of electronic components as demonstrated here in benchmark measurements performed on flash memories.

  2. Fast neutron irradiation tests of flash memories used in space environment at the ISIS spallation neutron source

    Directory of Open Access Journals (Sweden)

    C. Andreani

    2018-02-01

    Full Text Available This paper presents a neutron accelerated study of soft errors in advanced electronic devices used in space missions, i.e. Flash memories performed at the ChipIr and VESUVIO beam lines at the ISIS spallation neutron source. The two neutron beam lines are set up to mimic the space environment spectra and allow neutron irradiation tests on Flash memories in the neutron energy range above 10 MeV and up to 800 MeV. The ISIS neutron energy spectrum is similar to the one occurring in the atmospheric as well as in space and planetary environments, with intensity enhancements varying in the range 108- 10 9 and 106- 10 7 respectively. Such conditions are suitable for the characterization of the atmospheric, space and planetary neutron radiation environments, and are directly applicable for accelerated tests of electronic components as demonstrated here in benchmark measurements performed on flash memories.

  3. Measuring the cosmic ray muon-induced fast neutron spectrum by (n,p) isotope production reactions in underground detectors

    International Nuclear Information System (INIS)

    Galbiati, Cristiano; Beacom, John F.

    2005-01-01

    While cosmic ray muons themselves are relatively easy to veto in underground detectors, their interactions with nuclei create more insidious backgrounds via (i) the decays of long-lived isotopes produced by muon-induced spallation reactions inside the detector (ii) spallation reactions initiated by fast muon-induced neutrons entering from outside the detector, and (iii) nuclear recoils initiated by fast muon-induced neutrons entering from outside the detector. These backgrounds, which are difficult to veto or shield against; are very important for solar, reactor, dark matter, and other underground experiments, especially as increased sensitivity is pursued. We used FLUKA to calculate the production rates and spectra of all prominent secondaries produced by cosmic ray muons, in particular focusing on secondary neutrons, because of their importance. Since the neutron spectrum is steeply falling, the total neutron production rate is sensitive to just the relatively soft neutrons and not the fast-neutron component. We show that the neutron spectrum in the range ∼10-100 MeV can instead be probed by the (n,p)-induced isotope production rates 12 C(n,p) 12 B and 16 O(n,p) 16 N in oil- and water-based detectors. The result for 12 B is in good agreement with the recent KamLAND measurement. Besides testing the calculation of muon secondaries, these results are also of practical importance, since 12 B (T 1/2 =20.2 ms, Q=13.4 MeV) and 16 N (T 1/2 =7.13 s, Q=10.4 MeV) are among the dominant spallation backgrounds in these detectors

  4. Measurement of the thermal and fast neutron flux in a research reactor with a Li and Th loaded optical fibre detector

    CERN Document Server

    Yamane, Y; Misawa, T; Karlsson, J K H; Pázsit, I

    1999-01-01

    The spatial dependence of thermal and fast neutron flux was measured axially in the core of a 1 MW research reactor. The measurements were made by a thin optical fibre detector with a neutron sensitive ZnS(Ag) scintillation tip. For thermal neutrons sup 6 Li was used, whereas for fast neutrons sup 2 sup 3 sup 2 Th was used as neutron converter. The spatial dependence was measured by moving the fibre axially with a uniform speed. The measurement takes a few minutes, compared to up to 10 h with the conventional wire activation method. Comparison with traditional measurements shows a good agreement. (author)

  5. Defect structures in copper and gold irradiated with fast neutrons, 14 MeV neutrons and 600--800 MeV protons

    International Nuclear Information System (INIS)

    Horsewell, A.; Singh, B.N.; Sommer, W.F.; Heinisch, H.L.

    1989-01-01

    Copper and Gold have been irradiated with fast neutrons (mixed spectrum thermal reactor), 14 MeV neutrons (RTNS-II) and 600--800 MeV protons (PIREX II ampersand LAMPF) at 300--373 K over a dose range of 10 21 --10 24 particles·m -2 . Defect cluster concentrations and sizes have been obtained by transmission electron microscopy. The variation in cascade damage structures resulting from a change in average recoil energy from 10 4 to 10 6 eV is shown. 4 refs., 1 fig., 3 tabs

  6. Measurement of fluorine total concentration in dental enamel using fast neutron activation

    International Nuclear Information System (INIS)

    Mouadili, A.; Vernais, J.; Isabelle, D.B.

    1988-01-01

    Fluorine which is present in dental enamel, at the level of a few tens to a few hundred ppm, plays an important role in the behaviour of this tissue. Therefore quantitative determination is of interest for particular studies of the dental system. We present a nuclear nondestructive method to determine the total fluorine content in dental enamel by cyclotron-produced fast-neutron activation. The 19 F(n,2n) reaction leads to 18 F which is a β + emitter with a 109.8 min half-life. The irradiated sample activity is measured by detecting in coincidence the annihilation photons. A fluorine standard is used for calibration. The detection limit is of the order of 1 ppm, while the reproducibility is better than 95% [pt

  7. Evaluation of neutron streaming in fast breeder reactor fuel assembly by double heterogeneous modelling

    International Nuclear Information System (INIS)

    Unesaki, Hironobu; Takeda, Toshikazu

    1988-01-01

    Neutron streaming in a fast breeder reactor fuel assembly caused by the double heterogeneity structure is estimated by double heterogeneous modelling. The conventional pin cell model, a two-region subassembly model and the exact pin cluster model are used to take into account the streaming effect caused by the pin cell structure and the surrounding wrapper tube structure. The heterogeneity of wrapper tube and its surrounding sodium is explicitly considered. The streaming effect is evaluated based on Benoist's diffusion coefficient. The total streaming effect caused by the double heterogeneity structure of a fuel subassembly is found to be -0.2 % dk/kk' for k eff , which is almost twice that obtained from the conventional pin cell model of -0.1 % dk/kk'. (author)

  8. Fuel pin and subassembly heterogeneity effect on neutronics properties of a fast power reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kamei, T.; Yoshida, T. [Nippon Atomic Industry Group Co., Ltd., Tokyo (Japan)

    1980-09-15

    Heterogeneous structure of a fuel pin subassembly may exert influence on the neutronic properties of a fast power reactor such as criticality factor, sodium void reactivity, and Doppler coefficient. Study was performed to examine this effect quantitatively for a typical 1000 MW(e) power reactor. The heterogeneity effect was evaluated in two steps. One is for the heterogeneity of fuel pin cell loaded inside wrapper tubes. Another is for the gross heterogeneity of a subassembly, namely the lumped fuel-pins in the central part and the peripheral wrapper tube region. It is shown that the combined heterogeneity effect on k/sub eff/ is as large as 0.6%{Delta}/k. This large heterogeneity is mainly caused by the {sup 238}U resonance self-shielding effect.

  9. Light ions cyclotron bombardment to simulate fast neutron radiation damage in nuclear materials

    International Nuclear Information System (INIS)

    Segura, E.; Lucki, G.; Aguiar, D.

    1984-01-01

    The applicability and limitations of the use of cyclotron light ions bombardment to simulate the effects of the neutron irradiation are presented. Light ions with energies of about 10 MeV are capable to produce homogeneous damage in specimens suitable for measuring bulk mechanical properties although their low damage rate of 10 -5 dpa.sec -1 limit the dose range to a few dpa. On the other hand, cyclotron alpha particle implantation provides a fast and convenient way of introducing helium with a minimum of side effects so that we can take advantage of this technique to get better understanding of the mechanism by which this insoluble gas produces high temperature embrittlement. Some experimental details such as dimensions and cooling techniques are described. Finally a description of the infrastructure for cyclotron alpha particle implantation and a creep-test facility of the Division of Radiation Damage at IPEN-CNEN/SP are presented. (Author) [pt

  10. Fast and simple method for Goss texture evaluation by neutron diffraction

    Science.gov (United States)

    Kucerakova, M.; Kolařík, K.; Čapek, J.; Vratislav, S.; Kalvoda, L.

    2016-09-01

    Requirement of low power losses is one of the crucial demands laid on properties of electric steel sheets used in construction of various magnetic circuits. For cold-rolled grain- oriented (CRGO) Fe-3%Si sheets used in majority of power distribution transformers, the Goss texture {110} is known to provide the best utility properties (low power loses, high magnetic permeability). Due to the coarse grain size of CRGO steel, neutron diffraction (ND) is dominantly used to characterize the sheets' texture in order to achieve statistically significant data. In this paper, we present a fast and simple method for characterization of Goss texture perfection level in CRGO steel sheets based on monochromatic ND. The method is tested on 8 samples differing in fabrication technology and magnetic properties. Satisfactory performance of the method and its suitability for a detail texture analyses is tested by juxtaposition of the obtained textural and the magnetic characteristics measured by Barkhausen method.

  11. Texas Instruments TPS7H1101-SP Fast Neutron Irradiation Results

    CERN Document Server

    The ATLAS collaboration

    2015-01-01

    Texas Instruments’s TPS7H1101-SP is an ultra low drop-out voltage regulator that operates under a wide range of input voltages - 1.5 to 7V. It can operate under a load of at most 3A and is radiation qualified by Texas Instruments for Total Ionizing Dose (TID) effects and Single Event Effects (SEE). For the application of the TPS7H1101-SP on the Front End Boards (FEBs) of the New Small Wheel (NSW) of the ATLAS detector, we study its susceptibility to a third kind of radiation effect -displacement damage- and present its performance in fast neutrons up to a dose of 6 x 10$^{14}$ 1MeVNE/cm$^{2}$.

  12. Concealed nuclear material identification via combined fast-neutron/γ-ray computed tomography (FNGCT): a Monte Carlo study

    Science.gov (United States)

    Licata, M.; Joyce, M. J.

    2018-02-01

    The potential of a combined and simultaneous fast-neutron/γ-ray computed tomography technique using Monte Carlo simulations is described. This technique is applied on the basis of a hypothetical tomography system comprising an isotopic radiation source (americium-beryllium) and a number (13) of organic scintillation detectors for the production and detection of both fast neutrons and γ rays, respectively. Via a combination of γ-ray and fast neutron tomography the potential is demonstrated to discern nuclear materials, such as compounds comprising plutonium and uranium, from substances that are used widely for neutron moderation and shielding. This discrimination is achieved on the basis of the difference in the attenuation characteristics of these substances. Discrimination of a variety of nuclear material compounds from shielding/moderating substances (the latter comprising lead or polyethylene for example) is shown to be challenging when using either γ-ray or neutron tomography in isolation of one another. Much-improved contrast is obtained for a combination of these tomographic modalities. This method has potential applications for in-situ, non-destructive assessments in nuclear security, safeguards, waste management and related requirements in the nuclear industry.

  13. Fast-neutron and gamma-ray imaging with a capillary liquid xenon converter coupled to a gaseous photomultiplier

    Science.gov (United States)

    Israelashvili, I.; Coimbra, A. E. C.; Vartsky, D.; Arazi, L.; Shchemelinin, S.; Caspi, E. N.; Breskin, A.

    2017-09-01

    Gamma-ray and fast-neutron imaging was performed with a novel liquid xenon (LXe) scintillation detector read out by a Gaseous Photomultiplier (GPM). The 100 mm diameter detector prototype comprised a capillary-filled LXe converter/scintillator, coupled to a triple-THGEM imaging-GPM, with its first electrode coated by a CsI UV-photocathode, operated in Ne/5%CH4 at cryogenic temperatures. Radiation localization in 2D was derived from scintillation-induced photoelectron avalanches, measured on the GPM's segmented anode. The localization properties of 60Co gamma-rays and a mixed fast-neutron/gamma-ray field from an AmBe neutron source were derived from irradiation of a Pb edge absorber. Spatial resolutions of 12± 2 mm and 10± 2 mm (FWHM) were reached with 60Co and AmBe sources, respectively. The experimental results are in good agreement with GEANT4 simulations. The calculated ultimate expected resolutions for our application-relevant 4.4 and 15.1 MeV gamma-rays and 1-15 MeV neutrons are 2-4 mm and ~ 2 mm (FWHM), respectively. These results indicate the potential applicability of the new detector concept to Fast-Neutron Resonance Radiography (FNRR) and Dual-Discrete-Energy Gamma Radiography (DDEGR) of large objects.

  14. FEASIBILITY OF MEASURING IRON IN VIVO USING FAST 14 MEV NEUTRONS.

    Energy Technology Data Exchange (ETDEWEB)

    WIELOPOLSKI, L.

    2005-05-01

    In this short report, I reassess the feasibility of measuring iron in vivo in the liver and heart of thalassemia patients undergoing chelation therapy. Despite the multiplicity of analytical methods for analyzing iron, only two, magnetic resonance imaging, and magnetic susceptibility, are suitable for in vivo applications, and these are limited to the liver because of the heart's beat. Previously, a nuclear method, gamma-resonance scattering, offered a quantitative measure of iron in these organs; however, it was abandoned because it necessitated a nuclear reactor to produce the radioactive source. I reviewed and reassessed the status of two alternative nuclear methods, based on iron spectroscopy of gamma rays induced by fast neutron inelastic scattering and delayed activation in iron. Both are quantitative methods with high specificity for iron and adequate penetrating power to measure it in organs sited deep within the human body. My experiments demonstrated that both modalities met the stated qualitative objectives to measure iron. However, neutron dosimetry revealed that the intensity of the neutron radiation field was too weak to reliably assess the minimum detection limits, and to allow quantitative extrapolations to measurements in people. A review of the literature, included in this report, showed that these findings agree qualitatively with the published results, although the doses reported were about three orders-of-magnitude higher than those I used. Reviewing the limitations of the present work, steps were outlined for overcoming some of the shortcomings. Due to a dearth of valid quantitative alternatives for determining iron in vivo, I conclude that nuclear methods remain the only viable option. However, from the lessons learned, further systematic work is required before embarking on clinical studies.

  15. Neutronics aspects associated to irregular lattices in sodium fast reactors cores

    International Nuclear Information System (INIS)

    Gentili, Michele

    2015-01-01

    The fuel assemblies of SFR cores (sodium fast reactors) are normally arranged in hexagonal regular lattices, whose compactness is ensured in nominal operating conditions by thermal expansion of assemblies pads disposed on the six assembly wrapper faces. During the reactor operations, thermal expansion phenomena and irradiation creep phenomena occur and they cause the fuel assemblies to bow and to deform both radially and axially. The main goal of this PhD is the understanding of the neutronic aspects and phenomena occurring in case of core and lattice deformations, as much as the design and implementation of deterministic neutronic calculation schemes and methods in order to evaluate the consequences for the core design activities and the safety analysis. The first part of this work is focused on the development of an analytical model with the purpose to identify the neutronic phenomena that are the main contributors to the reactivity changes induced by lattice and core deformations. A first scheme based on the spatial mesh projection method has been conceived and implemented for the ERANOS codes (BISTRO, H3D and VARIANT) and to the SNATCH solver. The second calculation scheme propose is based on mesh deformation: the computing mesh is deformed as a function of the assembly displacement field. This methodology has been implemented for the solver SNATCH, which normally allows the Boltzmann equation to be solved for a regular mesh. Finally, an iterative method has been developed in order to fulfill an a-priori estimation of the maximal reactivity insertion as a function of the postulated mechanical energy provided to the core, as much as the deformation causing it. (author) [fr

  16. First-principles investigation of neutron-irradiation-induced point defects in B4C, a neutron absorber for sodium-cooled fast nuclear reactors

    Science.gov (United States)

    You, Yan; Yoshida, Katsumi; Yano, Toyohiko

    2018-05-01

    Boron carbide (B4C) is a leading candidate neutron absorber material for sodium-cooled fast nuclear reactors owing to its excellent neutron-capture capability. The formation and migration energies of the neutron-irradiation-induced defects, including vacancies, neutron-capture reaction products, and knocked-out atoms were studied by density functional theory calculations. The vacancy-type defects tend to migrate to the C–B–C chains of B4C, which indicates that the icosahedral cage structures of B4C have strong resistance to neutron irradiation. We found that lithium and helium atoms had significantly lower migration barriers along the rhombohedral (111) plane of B4C than perpendicular to this plane. This implies that the helium and lithium interstitials tended to follow a two-dimensional diffusion regime in B4C at low temperatures which explains the formation of flat disk like helium bubbles experimentally observed in B4C pellets after neutron irradiation. The knocked-out atoms are considered to be annihilated by the recombination of the close pairs of self-interstitials and vacancies.

  17. Neutron-induced reaction cross-sections of 93Nb with fast neutron based on 9Be(p,n) reaction

    Science.gov (United States)

    Naik, H.; Kim, G. N.; Kim, K.; Zaman, M.; Nadeem, M.; Sahid, M.

    2018-02-01

    The cross-sections of the 93Nb (n , 2 n)92mNb, 93Nb (n , 3 n)91mNb and 93Nb (n , 4 n)90Nb reactions with the average neutron energies of 14.4 to 34.0 MeV have been determined by using an activation and off-line γ-ray spectrometric technique. The fast neutrons were produced using the 9Be (p , n) reaction with the proton energies of 25-, 35- and 45-MeV from the MC-50 Cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS). The neutron flux-weighted average cross-sections of the 93Nb(n , xn ; x = 2- 4) reactions were also obtained from the mono-energetic neutron-induced reaction cross-sections of 93Nb calculated using the TALYS 1.8 code, and the neutron flux spectrum based on the MCNPX 2.6.0 code. The present results for the 93Nb(n , xn ; x = 2- 4) reactions are compared with the calculated neutron flux-weighted average values and found to be in good agreement.

  18. Membrane solubilization in erythrocytes as a measure of radiation exposure to fast neutrons

    International Nuclear Information System (INIS)

    Soltan Monem, A.; Ali, F.M.; Ali, S.A.; Al-thani, N.J.J.

    1999-01-01

    Membrane solubilization and osmotic fragility of rat erythrocytes irradiated in vivo with fast neutron fluences ranging from 10 6 to 5x10 7 n cm -2 using a 252 Cf source were measured instantaneously using a light scattering technique. The solubilization of erythrocyte membrane by a non-ionic detergent, octylglucoside (OG), was found to exhibit a two stage transition from vesicular form to mixed micellar form in the range of detergent concentrations 1.5-7.8 mM. The coexistence phase, vesicular/mixed micellar, was shifted towards higher detergent concentrations with increase in the neutron fluence, indicating increasing membrane resistance to the detergent and hence change in the natural membrane permeation properties. The technique shows an adequate sensitivity in detecting membrane damage in erythrocytes and has potential as a biophysical marker of radiation exposure. The osmotic fragility of irradiated erythrocytes shows a decreasing trend with increasing irradiation fluence measured directly and two weeks post-irradiation. Blood films photographed two weeks post-irradiation show developed elliptocytosis and crenated cell anaemia. (author)

  19. Evolution of thermo-physical properties and annealing of fast neutron irradiated boron carbide

    Science.gov (United States)

    Gosset, Dominique; Kryger, Bernard; Bonal, Jean-Pierre; Verdeau, Caroline; Froment, Karine

    2018-03-01

    Boron carbide is widely used as a neutron absorber in most nuclear reactors, in particular in fast neutron ones. The irradiation leads to a large helium production (up to 1022/cm3) together with a strong decrease of the thermal conductivity. In this paper, we have performed thermal diffusivity measurements and X-ray diffraction analyses on boron carbide samples coming from control rods of the French Phenix LMFBR reactor. The burnups range from 1021 to 8.1021/cm3. We first confirm the strong decrease of the thermal conductivity at the low burnup, together with high microstructural modifications: swelling, large micro-strains, high defects density, and disordered-like material conductivity. We observe the microstructural parameters are highly anisotropic, with high micro-strains and flattened coherent diffracting domains along the (00l) direction of the hexagonal structure. Performing heat treatments up to high temperature (2200 °C) allows us to observe the material thermal conductivity and microstructure restoration. It then appears the thermal conductivity healing is correlated to the micro-strain relaxation. We then assume the defects responsible for most of the damage are the helium bubbles and the associated stress fields.

  20. Using the transportable, computer-operated, liquid-scintillator fast-neutron spectrometer system

    International Nuclear Information System (INIS)

    Thorngate, J.H.

    1988-01-01

    When a detailed energy spectrum is needed for radiation-protection measurements from approximately 1 MeV up to several tens of MeV, organic-liquid scintillators make good neutron spectrometers. However, such a spectrometer requires a sophisticated electronics system and a computer to reduce the spectrum from the recorded data. Recently, we added a Nuclear Instrument Module (NIM) multichannel analyzer and a lap-top computer to the NIM electronics we have used for several years. The result is a transportable fast-neutron spectrometer system. The computer was programmed to guide the user through setting up the system, calibrating the spectrometer, measuring the spectrum, and reducing the data. Measurements can be made over three energy ranges, 0.6--2 MeV, 1.1--8 MeV, or 1.6--16 MeV, with the spectrum presented in 0.1-MeV increments. Results can be stored on a disk, presented in a table, and shown in graphical form. 5 refs., 51 figs