High energy resolution characteristics on 14MeV neutron spectrometer for fusion experimental reactor

Energy Technology Data Exchange (ETDEWEB)

Iguchi, Tetsuo [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab.; Takada, Eiji; Nakazawa, Masaharu

1996-10-01

A 14MeV neutron spectrometer suitable for an ITER-like fusion experimental reactor is now under development on the basis of a recoil proton counter telescope principle in oblique scattering geometry. To verify its high energy resolution characteristics, preliminary experiments are made for a prototypical detector system. The comparison results show reasonably good agreement and demonstrate the possibility of energy resolution of 2.5% in full width at half maximum for 14MeV neutron spectrometry. (author)

Gamma-ray-spectroscopy following high-flux 14-MeV neutron activation

International Nuclear Information System (INIS)

Williams, R.E.

1981-01-01

The Rotating Target Neutron Source (RTNS-I), a high-intensity source of 14-MeV neutrons at the Lawrence Livermore National Laboratory (LLNL), has been used for applications in activation analysis, inertial-confinement-fusion diagnostic development, and fission decay-heat studies. The fast-neutron flux from the RTNS-I is at least 50 times the maximum fluxes available from typical neutron generators, making these applications possible. Facilities and procedures necessary for gamma-ray spectroscopy of samples irradiated at the RTNS-I were developed

Gamma-ray-spectroscopy following high-flux 14-MeV neutron activation

Energy Technology Data Exchange (ETDEWEB)

Williams, R.E.

1981-10-12

The Rotating Target Neutron Source (RTNS-I), a high-intensity source of 14-MeV neutrons at the Lawrence Livermore National Laboratory (LLNL), has been used for applications in activation analysis, inertial-confinement-fusion diagnostic development, and fission decay-heat studies. The fast-neutron flux from the RTNS-I is at least 50 times the maximum fluxes available from typical neutron generators, making these applications possible. Facilities and procedures necessary for gamma-ray spectroscopy of samples irradiated at the RTNS-I were developed.

A new method for the determination of unknown neutron fluence for 14.0 MeV

Energy Technology Data Exchange (ETDEWEB)

Malik, Fariha [Physics Reasearch Division, PINSTECH, Nilore, Islamabad (Pakistan)]. E-mail: fariha@pinstech.org.pk; Khan, Ehsan U. [Department of Physics, CIIT, Islamabad (Pakistan); Qureshi, Imtinan [Physics Reasearch Division, PINSTECH, Nilore, Islamabad (Pakistan); Husaini, Syed N. [Physics Reasearch Division, PINSTECH, Nilore, Islamabad (Pakistan); Ahmad, Waqar [Physics Reasearch Division, PINSTECH, Nilore, Islamabad (Pakistan); Rajput, Usman [Physics Reasearch Division, PINSTECH, Nilore, Islamabad (Pakistan); Raza, Qaiser [Applied Physics Division, PINSTECH, Nilore, Islamabad (Pakistan)

2006-11-15

Measuring the correct neutron fluence in various energy intervals in and around the neutron sources is important for the purpose of personnel and environmental neutron dosimetry. In this paper, we present a new method for the measurement of the fluence of mono-energetic neutrons having the energy of 14.0 MeV. The samples exposed to neutrons from the 14.0 MeV neutron generator at PINSTECH with various fluence values ranging from 10{sup 7} to 10{sup 10} n cm{sup -2} were etched for 10 min in 6 N NaOH at 70.0{+-}1.0 {sup o}C and the transmittance of UV radiation was measured using a spectrophotometer. This procedure was repeated 20 times after etching the same sample each time for increasing time intervals till the stage when transmittance reached the constant minimum value. An exponential decay of the transmittance has been observed with respect to the increasing etching time interval in each of the samples exposed to various neutron fluence. Further, it has also been observed that there is a linear relationship between the transmittance decay constant and neutron fluence. Hence, the linear graph can be used as a calibration for measuring the unknown fluence of 14.0 MeV neutrons.

Measurements of 14 MeV neutron multiplication in spherical beryllium shells

International Nuclear Information System (INIS)

Moellendorff, U. von; Alevra, A.V.; Giese, H.; Kappler, F.; Klein, H.; Klein, H.; Tayama, R.

1995-01-01

New results of spherical-shell transmission measurements with 14MeV neutrons on pure beryllium shells up to 17cm thick are reported. The total leakage neutron multiplications were measured using a Bonner sphere system. Independently, the leakage neutron spectra were measured over the entire energy range, 15MeV to thermal energies, by proton-recoil and time-of-flight methods. The total leakage multiplications are in excellent agreement with three-dimensional Monte Carlo calculations using beryllium nuclear data based on the Young and Stewart evaluation. The leakage in the evaporation energy window confirms the Be(n,2n) cross-section of the Young and Stewart evaluation rather than that used in the ENDF/B-VI library. At energies below 1keV, a surplus of leakage neutrons over the calculation is found for smaller beryllium thicknesses. (orig.)

Transmission of 14 MeV neutrons through concrete, soil, sugar, wood and coal samples - a Monte Carlo Study

International Nuclear Information System (INIS)

Abdelmonem, M.S.; Naqvi, A.A.

2006-01-01

Full text: Fast neutrons transmission measurements are ideal for the elemental analysis of bulk samples. In particular, they can be used to determine the hydrogen concentration in bulk samples. In the present study, Monte Carlo simulations have been carried to calculate the intensity of 14 MeV neutrons transmitted through concrete, soil, sugar, wood and coal samples. The simulated set-up consists of a cylindrical sample, placed at a distance of 9 cm from the neutron source. Fast neutrons transmitted through the sample are collimated through a double truncated neutron collimator to a fast neutron detector. The collimator contains a mixture of paraffin and lithium carbonate. In this study, transmitted intensity of fast neutron through each sample was calculated as a function of moisture contents of the sample for 14 MeV neutrons. The moisture contents of the samples were varied over 0-7 wt. %. The calculated intensity of 14 MeV neutrons transmitted through the samples, shows effects related to fast neutron thermalization in hydrogen of moisture and energy dependence of neutron transmission through the sample materials. This is clearly shown by different gradients of neutron yield vs moisture content curves of these samples. The gradient of the neutron yield curves for the 14 MeV neutrons has a lower value than those reported for a 241 Am-Be neutron source

Calibration Of A 14 MeV Neutron Generator With Reference To NBS-1

International Nuclear Information System (INIS)

Heimbach, Craig R.

2011-01-01

NBS-1 is the US national neutron reference source. It has a neutron emission rate (June 1961) of 1.257x10 6 n/s 1,2,3 with an uncertainty of 0.85%(k = 1). Neutron emission-rate calibrations performed at the National Institute of Standards and Technology (NIST) are made in comparison to this source, either directly or indirectly. To calibrate a commercial 14 MeV neutron generator, NIST performed a set of comparison measurements to evaluate the neutron output relative to NBS-1. The neutron output of the generator was determined with an uncertainty of about 7%(k = 1). The 15-hour half-life of one of the reactions used also makes possible off-site measurements. Consideration is given to similar calibrations for a 2.5 MeV neutron generator.

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

Science.gov (United States)

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

2018-02-01

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

Contribution to the determination of Sb-Ag-Cu-Ga-Mo-Zn using 14 MeV neutron activation; Contribution au dosage de Sb-Ag-Cu-Ga-Mo-Zn par activation aux neutrons de 14 MeV

Energy Technology Data Exchange (ETDEWEB)

Crambes, M [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1966-04-01

By using, 14 MeV, neutron irradiation it is possible to extend the field of application of neutron radio-activation analysis, in particular to the case of light elements. For, many other elements it can replace in-pile irradiation thereby making it possible, thanks to portable 14 MeV neutron generators, to carry out radio-activation analyses away from nuclear-research c e n t r e s. With a view to applying this analytical technique to routine work, we have developed some rapid chemical separation methods in order to make possible the determination of several elements which after exposure to fast neutrons, produce {beta} emitting nuclides which cannot be differentiated by a simple instrumental study, the emitted radiation being of the same type and of similar half-life the two cases. (author) [French] L'irradiation au moyen de neutrons de 14 MeV permet d'etendre le domaine d'application de l'analyse par radioactivation neutronique, en particulier aux elements legers. Cependant pour de nombreux autres elements elle peut remplacer l'irradiation en reacteur nucleaire permettant ainsi grace aux ensembles portables producteurs de neutrons de 14 MeV, l'extension de l'analyse par radioactivation a l'exterieur des centres d'etudes nucleaires. Dans le but d'appliquer cette methode d'analyse a des travaux de routine, nous avons mis au point des separations chimiques rapides, afin de permettre le dosage de quelques elements qui par irradiation aux neutrons rapides, engendrent des nucleides emetteurs {beta} qu'une simple etude instrumentale ne peut differencier en raison de l'identite de leur rayonnement et de leurs periodes radioactives trop proches. (auteur)

The shielding performance of multilayer composite shielding structures to 14.8 MeV fast neutrons

International Nuclear Information System (INIS)

Shen Zhiqiang; Kang Qing; Xu Jun; Wang Zhenggang; Lu Nan

2014-01-01

Cement-based round thin-layer samples mixed with 30% quality content of barite, and 20% quality content of carbide boron has Prepared, the same-diameter sliced samples of pure graphite and pure polyethylene has cut, then, samples combination and cross stack order has designed, formed four species Multilayer Composite shield structure, at last, neutron attenuation measurements has been done by experimental system of using 14.8 MeV neutrons from the 5SDH-2 accelerator and long counter composition, penetrating rate of samples and the shield structure to 14.8 MeV fast neutron has tested, and attenuation section has calculated. Results show that 14.8 MeV fast neutrons to higher penetration rates of thin layer samples, attenuation cross section of samples distinguish small between each other, must be increasing the thickness of the samples to reduce the experimental uncertainty; through composed of attenuation cross section and thickness parameters of composite structure, can more accurately predict the shielding ability of composite structures, error between calculation results and experimental results in 4%. (authors)

Nuclear and activation characteristics of materials in 14.1-MeV and 2.5-MeV neutron field

International Nuclear Information System (INIS)

Seki, Yasushi; Takeyasu, Yuuichi.

1988-11-01

The nuclear and activation characteristics of various materials and elements of interest in terms of fusion reactor design are calculated and the results are graphically shown. The elements and materials are placed in a simple geometry modelling a blanket and shield of a fusion reactor. The neutrons with 14.1-MeV and 2.5-MeV energy are generated from the region represented as D-T and D-D plasma, respectively. The following activation characteristics after neutron irradiation are shown for each material and element; 1. Time evolution of induced activity, 2. Time evolution of decay heat, 3. Delayed gamma-ray dose distribution, 4. Decay heat distribution. In addition to the above activation characteristics, nuclear characteristics during the neutron irradiation, e.g. neutron energy spectra, neutron and gamma-ray flux distribution, nuclear heating distributions, and neutron and gamma-ray dose rate are also shown. (author)

Secondary neutron double differential cross sections from 209Bi at 14.2 MeV

International Nuclear Information System (INIS)

Shen Guanren; Xia Haihong; Tang Hongqing

1992-01-01

The secondary neutron double differential cross sections from 209 Bi at 14.2 MeV have been measured at 6 angles between 25 degree-150 degree using an associated particle TOF spectrometer. Flight path was 2.7 m. The neutron detector was biased at 1.3 MeV. The time resolution was about 1.2 ns. The data were compared with existing data and theoretical calculated results. Good agreement is achieved

Simulation code for the interaction of 14 MeV neutrons on cells

Energy Technology Data Exchange (ETDEWEB)

Nenot, M.L.; Alard, J.P.; Dionet, C.; Arnold, J.; Tchirkov, A.; Meunier, H.; Bodez, V.; Rapp, M.; Verrelle, P

2002-07-01

The structure of the survival curve of melanoma cells irradiated by 14 MeV neutrons displays unusual features at very low dose rate where a marked increase in cell killings at 0.05 Gy is followed by a plateau for survival from 0.1 to 0.32 Gy. In parallel a simulation code was constructed for the interaction of 14 MeV neutrons with cellular cultures. The code describes the interaction of the neutrons with the atomic nuclei of the cellular medium and of the external medium (flask culture and culture medium), and is used to compute the deposited energy into the cell volume. It was found that the large energy transfer events associated with heavy charged recoil can occur and that a large part of the energy deposition events are due to recoil protons emitted from the external medium. It is suggested that such events could partially explain the experimental results. (author)

Experiment and analysis of neutron spectra in a concrete assembly bombarded by 14 MeV neutrons

International Nuclear Information System (INIS)

Oishi, Koji; Tomioka, Kazuyuki; Ikeda, Yujiro; Nakamura, Tomoo.

1988-01-01

Neutron spectrum in concrete bombarded by 14 MeV neutrons was measured using a miniature NE213 spectrometer and multi-foil activation method. A good agreement between those two experimental methods was obtained within experimental errors. The measured spectrum was compared with calculated ones using two-dimensional transport code DOT3.5 with 125 group structure cross section libraries based on ENDF/B-IV, JENDL-2, and JENDL-3T (the testing version of JENDL-3.) In the D-T neutron peak region, measured and calculated neutron spectra agreed well with each other for those libraries. However, disagreements of about -10 % to +50 % and -30 % to +40 % were obtained in the MeV region and still lower neutron energy range, respectively. As a result, it was concluded that those discrepancies were caused by the overestimation of secondary neutrons emitted by inelastic scattering from O, Si, and/or Ca which were the main components of concrete. (author)

High energy proton simulation of 14-MeV neutron damage in Al2O3

International Nuclear Information System (INIS)

Muir, D.W.; Bunch, J.M.

1975-01-01

High-energy protons are a potentially useful tool for simulating the radiation damage produced by 14-MeV neutrons in CTR materials. A comparison is given of calculations and measurements of the relative damage effectiveness of these two types of radiation in single-crystal Al 2 O 3 . The experiments make use of the prominent absorption band at 206 nm as an index to lattice damage, on the assumption that peak absorption is proportional to the concentration of lattice vacancies. The induced absorption is measured for incident proton energies ranging from 5 to 15 MeV and for 14-MeV neutrons. Recoil-energy spectra are calculated for elastic and inelastic scattering using published angular distributions. Recoil-energy spectra also are calculated for the secondary alpha particles and 12 C nuclei produced by (p,p'α) reactions on 16 O. The recoil spectra are converted to damage-energy spectra and then integrated to yield the damage-energy cross section at each proton energy and for 14 MeV neutrons. A comparison of the calculations with experimental results suggests that damage energy, at least at high energies, is a reasonable criterion for estimating this type of radiation damage. (auth)

The shielding of a 14 MeV neutron generator

International Nuclear Information System (INIS)

Brighton, D.R.

1976-10-01

The concrete masonry shield for a 14 MeV neutron generator was designed using data supplied by the manufacturer. Subsequent radiation surveys outside the shield showed doses higher than expected. Calculations indicated the sensitivity of dose transmission factors to concrete composition. The observed dose transmission factor agreed with that of Broerse but not with that of Hacke and Prudhomme. Measurements and calculations delineated the contribution that neutrons, scattered from the upper wall that supports the laboratory roof, made to the dose in adjoining areas. In redesigning the shield a compromise was made between additional cost and restrictions on the generator's duty cycle, which is automatically controlled to ensure personnel safety. (Author)

Transport calculations for a 14.8 MeV neutron beam in a water phantom

International Nuclear Information System (INIS)

Goetsch, S.J.

1981-01-01

A coupled neutron/photon Monte Carlo radiation transport code (MORSE-CG) has been used to calculate neutron and photon doses in a water phantom irradiated by 14.8 MeV neutrons from the Gas Target Neutron Source. The source-collimator-phantom geometry was carefully simulated. Results of calculations utilizing two different statistical estimators (next-collision and track-length) are presented

The design of a proton recoil telescope for 14 MeV neutron spectrometry

Energy Technology Data Exchange (ETDEWEB)

Hawkes, N.P.; Bond, D.S.; Croft, S.; Jarvis, O.N. E-mail: onj@jet.uk; Sherwood, A.C

2002-01-01

As part of the design effort for a 14 MeV neutron spectrometer for the Joint European Torus (JET), computer codes were developed to calculate the response of a proton recoil telescope comprising a proton radiator film mounted in front of a proton detector. The codes were used to optimise the geometrical configuration in terms of efficiency and resolution, bearing in mind the constraints imposed by the proposed application as a JET neutron diagnostic for the Deuterium-Tritium phase. A prototype instrument was built according to the optimised design, and tested with monoenergetic 14 MeV neutrons from the Harwell 500 keV Van de Graaff accelerator. The measured energy resolution and absolute efficiency were found to be in acceptable agreement with the calculations. Based on this work, a multi-radiator production version of the spectrometer has now been constructed and successfully deployed at JET.

The design of a proton recoil telescope for 14 MeV neutron spectrometry

International Nuclear Information System (INIS)

Hawkes, N.P.; Bond, D.S.; Croft, S.; Jarvis, O.N.; Sherwood, A.C.

2002-01-01

As part of the design effort for a 14 MeV neutron spectrometer for the Joint European Torus (JET), computer codes were developed to calculate the response of a proton recoil telescope comprising a proton radiator film mounted in front of a proton detector. The codes were used to optimise the geometrical configuration in terms of efficiency and resolution, bearing in mind the constraints imposed by the proposed application as a JET neutron diagnostic for the Deuterium-Tritium phase. A prototype instrument was built according to the optimised design, and tested with monoenergetic 14 MeV neutrons from the Harwell 500 keV Van de Graaff accelerator. The measured energy resolution and absolute efficiency were found to be in acceptable agreement with the calculations. Based on this work, a multi-radiator production version of the spectrometer has now been constructed and successfully deployed at JET

14.2 MeV neutron induced U-235 fission cross section measurement

International Nuclear Information System (INIS)

Li Jingwen; Shen Guanren; Ye Zongyuan; Li Anli; Zhou Shuhua; Sun Zhongfan; Wu Jingxia; Huang Tanzi

1986-01-01

The cross section of U-235 fission induced by 14.2 MeV neutrons was measured by the time correlated associated particle method. The result obtained is (2.078+-0.040) barn. Comparison with other author's is also given. (author)

Scattering of 14.6 MeV neutrons from Fe and evidence for structure in the emitted neutron spectra

International Nuclear Information System (INIS)

Gul, K.; Anwar, M.; Ahmad, M.; Saleem, S.M.; Khan, N.A.

1984-06-01

Structure in the spectra of neutrons emitted from iron on bombardment with 14.6 MeV neutrons has been investigated and explained in terms of excitation of levels in iron 56. The energies of scattered neutrons have been measured by the time-of-flight technique based on the associated particle method. The observed excitations have been correlated with the reported levels in a satisfactory manner. Evidence for new excitations at 8.8 +- 0.02, 9.8 +- 0.1, 10.2 +- 0.1, 12.44 +- 0.03 and 12.52 +- 0.03 MeV has been obtained. The excitation of possible components of Ml giant resonance in iron 56 is discussed. (author)

Measurement of uranium enrichment by 14 MeV neutron irradiation

International Nuclear Information System (INIS)

Rezende, H.R.

1987-01-01

a non-destructive technique for the determination of uranium in UO 2 samples was developed, making use of the change in the fission cross section of a nuclide with the neutron energy. The active interrogation method was used by irradiating the samples with pulsed 14 MeV neutrons and further detection of delayed fission neutrons. In order to discriminate U-238 from U-235 the neutron energy was tailored by means of two concentric cylinders of lead and paraffin/poliethylene, 11 and 4 cm thick. Between neutron pulses, delayed neutrons from fission were detected by a long counter built with five BF 3 proportional counters. Calibration curves for enrichment and total mass versus delayed neutron response were obtained using available UO 2 pellets of known enrichment. Enrichment detection limit, obtained with 95% confidence level by the Student distribution was estimated to be 0.33%. The minimal detectable mass was estimated to be 4.4 g. (author) [pt

Measure of uranium enrichment by 14 MeV neutron irradiation

International Nuclear Information System (INIS)

Rezende, H.R.

1987-01-01

A non-destructive technique for the determination of uranium in UO 2 samples was developed, marking use of the change in the fission cross of a nuclide with the neutron energy. The active interrogation method was used by irradiating the samples with pulsed 14 MeV neutrons and furtherdetection of delayed fission neutrons. In order to descriminated U-238 from U-235 the neutron energy was tailored by means of two concentric cylinders of lead and paraffin/poliethylene, 11 and 4 cm thick. Between neutron pulses, delayed neutrons from fission were detected by a long counter built with five BF 3 proportional counters. Calibration curves for enrichment and total mass versus delayed neutron response were obtained using available UO 2 pellets of Known enrichment. Enrichment detection limit, obtained with 95% confidence level by the the Student distribution was estimated to be 0.33%. The minimal detectable mass was estimated to be 4.4 g. (Author) [pt

Gamma-ray emission spectra from spheres with 14 MeV neutron source

International Nuclear Information System (INIS)

Yamamoto, Junji; Kanaoka, Takeshi; Murata, Isao; Takahashi, Akito; Sumita, Kenji

1989-01-01

Energy spectra of neutron-induced gamma-rays emitted from spherical samples were measured using a 14 MeV neutron source. The samples in use were LiF, Teflon:(CF 2 ) n , Si, Cr, Mn, Co, Cu, Nb, Mo, W and Pb. A diameter of the sphere was either 40 or 60 cm. The gamma-ray energy in the emission spectra covered the range from 500 keV to 10 MeV. Measured spectra were compared with transport calculations using the nuclear data files of JENDL-3T and ENDF/B-IV. The agreements between the measurements and the JENDL-3T calculations were good in the emission spectra for the low energy gamma-rays from inelastic scattering. (author)

Ion tail formation and its effect on 14-MeV neutron generation in D-3He plasmas

International Nuclear Information System (INIS)

Matsuura, H.; Nakao, Y.; Kudo, K.

1992-01-01

This paper reports on the triton distribution function in D- 3 He plasmas which is distorted from a Maxwellian owing to the presence of a 1.01-MeV birth component. The deuteron-triton reaction rate (i.e., 14-MeV neutron generation rate) in the plasma should be smaller than the values evaluated by assuming a Maxwellian triton distribution. A local Fokker-Planck calculation shows that although the degree of the decrease in 14-MeV neutron generation strongly depends on the plasma conditions and also on the energy loss mechanism, it becomes appreciable in actual burning plasmas

Scintillating-fiber imaging detector for 14-MeV neutrons

International Nuclear Information System (INIS)

Ress, D.; Lerche, R.A.; Ellis, R.J.; Heaton, G.W.; Nelson, M.B.; Mant, G.; Lehr, D.E.

1994-01-01

The authors have created a detector to image the neutrons emitted by imploded inertial-confinement fusion targets. The 14-MeV neutrons, which are produced by deuterium-tritium fusion events in the target, pass through an aperture to create an image on the detector. The neutron radiation is converted to blue light (430 nm) with a 20-cm-square array of plastic scintillating fibers. Each fiber is 10-cm long with a 1-mm-square cross section; approximately 35-thousand fibers make up the array. The resulting blue-light image is reduced and amplified by a sequence of fiber-optic tapers and image intensifiers, then acquired by a CCD camera. The fiber-optic readout system was tested optically for overall throughput the resolution. The authors plan to characterize the scintillator array reusing an ion-beam neutron source as well as DT-fusion neutrons emitted by inertial confinement targets. Characterization experiments will measure the light-production efficiency, spatial resolution, and neutron scattering within the detector. Several neutron images of laser-fusion targets have been obtained with the detector. Several neutron images of laser-fusion targets have been obtained with the detector. They describe the detector and their characterization methods, present characterization results, and give examples of the neutron images

Measurement of the angular distribution of 14 MeV neutrons scattered inelastically from the 0+ level at 7.65 MeV to {sup 12}C (1964); Mesure de la distribution angulaire a 14 MeV de neutrons de diffusion inelastique sur le niveau 0+ de 7,65 MeV du {sup 12}C (1964)

Energy Technology Data Exchange (ETDEWEB)

Szabo, I [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1963-11-15

Inelastic scattering of 14 MeV neutrons from {sup 12}C and angular distribution for the 0{sup +} (7,65 MeV) level, with a time-of-flight spectrometer (over-all resolution 1.4 ns), gives strong forward maximum {sigma}({theta} 15 deg.) {approx_equal} 8 mb/sr suggesting a direct-interaction process. (author) [French] Realisation d'un spectrometre de neutrons rapides a temps-de-vol de resolution totale 1,4 ns. Application: {sup 12}C (n,n') {sup 12}C (7,65 MeV) donnant {sigma}{sub t} {approx_equal} 20 mb, une forte emission vers l'avant {sigma}({theta} 15 deg.) {approx_equal} 8 mb/sr indiquont un processus d'interaction directe. (auteur)

Neutron leakage spectra from Be, Pb and U spheres at 14 MeV energy

International Nuclear Information System (INIS)

Androsenko, A.A.; Androsenko, P.A.; Devkin, B.V.

1989-01-01

Experimental data on neutron leakage spectra from beryllium, lead and uranium spheres with a central 14 MeV neutron source using a time-of-flight spectrometer have been measured. The data were compared with those calculated with the BLANK code using different nuclear data files. 15 refs, 1 fig., 2 tabs

Sputtering of vanadium and niobium under 14.1 MeV neutron impact

International Nuclear Information System (INIS)

Kaminsky, M.; Das, S.K.

1976-01-01

The recent studies of particle emission from cold-rolled and annealed niobium under 14.1-MeV neutron impact were extended to a heavily etched, polycrystalline niobium surface and to cold worked vanadium surfaces with different degrees of microstructure. The type and amount of material released and deposited on collector surfaces facing the irradiated targets were determined by three analytical techniques. Two types of deposits were found for certain types of surfaces--one in the form of chunks; the other as a fractional atom layer covering the surface. The chunks vary significantly in size. The small number of chunks observed suggests that the ejection of chunks is a relatively rare event in comparison to the total number of primary knock-on events produced by 14-MeV neutrons in near surface regions. Estimates of the total sputtering yield based on the chunk deposits and on the fractional atom layer deposit will be given

Helium production cross section Measurement of Pb and Sn for 14.9 MeV neutrons

Energy Technology Data Exchange (ETDEWEB)

Takao, Yoshiyuki; Fujimoto, Toshihiro; Ozaki, Shuji; Muramasu, Masatomo; Nakashima, Hideki [Kyushu Univ., Fukuoka (Japan); Kanda, Yukinori; Ikeda, Yujiro

1998-03-01

Helium production cross sections of lead and tin for 14.9 MeV neutrons were measured by helium accumulation method. Lead and tin samples were irradiated with FNS, an intense d-T neutron source of JAERI. The amount of helium produced in the samples by the neutron irradiation was measured with the Helium Atoms Measurement System (HAMS) at Kyushu University. As the samples contained a small amount of helium because of their small helium production cross sections at 14.9 MeV, the samples were evaporated by radiation from a tungsten filament to decrease background gases at helium measurement. Uncertainties of the present results were less than {+-}4.4%. The results were compared with other experimental data in the literature and also compared with the evaluated values in JENDL-3.2. (author)

Response of LR-115 type II and CR-39 plastic track detectors to Am-Be and 14.1-MeV neutrons

International Nuclear Information System (INIS)

Bradley, D.A.; Chong, C.S.; Saat, Ahmat; Sidik, A.G.; Ghose, A.M.

1987-01-01

The fast-neutron response of the plastic LR-115 type II and CR-39 track detectors have been compared, using a 14.1-MeV neutron generator and a radionuclide Am-Be neutron source (effective primary neutron energy 4.5-MeV). The distribution of track diameters for a range of etching times has been evaluated, taking into account track registration efficiency and the relevant fast neutron scattering cross-sections. The efficiency of etched-track formation in LR-115 type II due to neutron irradiation is approximately double that in CR-39. The 14.1-MeV neutrons also tend to produce tracks in both materials with somewhat greater efficiency than do the lower energy neutrons from the radionuclide source, for a given etching time. (author)

Advances in 14 MeV neutron activation analysis by means of a new intense neutron source

International Nuclear Information System (INIS)

Pepelnik, R.; Fanger, H.-U.; Michaelis, W.; Anders, B.

1982-01-01

A new intense 14 MeV neutron generator with cylindrical acceleration structure has been put in operation at the GKSS Research Center Geesthacht. The sealed neutron tube is combined with a fast pneumatic rabbit system with particular capabilities for neutron activation analysis involving short-lived reaction products. The sample transfer time is less than 140 ms. The maximum neutron flux available for activation is 5.2x10 10 n/cm 2 s. Theoretical sensitivity predictions made in a previous study have been verified for some important trace elements. As a first application, samples of freeze-dried suspended matter and fishes of the Elbe river were analyzed. (author)

Experimental techniques and theoretical models for the study of integral 14 MeV neutron cross sections

International Nuclear Information System (INIS)

Csikai, J.

1981-01-01

Owing to technical reasons, most of the data for fast neutron-induced reactions were measured at 14 MeV and the free parameters in nuclear reaction models have been determined at this energy. The discrepancies between experiment and theory are often due to the unmeasured or unreliable experimental data; therefore, it is important to survey the present techniques used for the measurement of total, elastic, nonelastic and partial nonelastic [(n,xn); (n,x charged); (n,f); (n,γ)] cross sections for 14 MeV neutrons. Systematics in the data as well as theoretical and semi-empirical models are also outlined. (author)

Consistency of neutron cross-section data, S /SUB N/ calculations, and measured tritium production for a 14-MeV neutron-driven sphere of natural lithium deuteride

International Nuclear Information System (INIS)

Reupke, W.A.; Davidson, J.N.; Muir, D.W.

1982-01-01

The authors present algorithms, describe a computer program, and gives a computational procedure for the statistical consistency analysis of neutron cross-section data, S /SUB N/ calculations, and measured tritium production in 14-MeV neutron-driven integral assemblies. Algorithms presented include a reduced matrix manipulation technique suitable for manygroup, 14-MeV neutron transport calculations. The computer program incorporates these algorithms and is expanded and improved to facilitate analysis of such integral experiments. Details of the computational procedure are given for a natural lithium deuteride experiment performed at the Los Alamos National Laboratory. Results are explained in terms of calculated cross-section sensitivities and uncertainty estimates. They include a downward adjustment of the 7 Li(n,xt) 14-MeV cross section from 328 + or - 22 to 284 + or - 24 mb, which is supported by the trend of recent differential and integral measurements. It is concluded that with appropriate refinements, the techniques of consistency analysis can be usefully applied to the analysis of 14-MeV neutron-driven tritium production integral experiments

Interaction of 14 MeV neutrons with hydrogenated target proton emission calculation

International Nuclear Information System (INIS)

Martin, G.; Perez, N.; Desdin.

1996-01-01

Using neutron emission data of a 14 MeV neutron generator, a paraffin target, and based on the n + H 1 → n '+ p reaction, have been obtained the characteristics of the proton emission in a proton-neutron mixed field. It was used Monte Carlo simulation and it was obtained the proton output as function of the converter width and the energy spectrum of protons corresponding to different converter thickness. Among 0.07 and 0.2 cm there is a maximum zone for the proton emission. The energy spectrum agrees with obtained on previous papers. Figures showing these results are provided

A 14 MeV neutron irradiation facility with an automated fast cyclic pneumatic

International Nuclear Information System (INIS)

Montgomery, M.T.; Yoho, M.D.; Biegalski, S.R.; Landsberger, S.; Welch, L.

2016-01-01

This work details the design criteria, construction, controls, and optimization of the 14 MeV neutron irradiation facility at the University of Texas, built with the motivation of performing neutron activation analysis on samples with short half-lives. The facility couples a D-T neutron generator with a pneumatic transfer system capable of transit of approximately one second between source and detector, while the cyclic automated nature allows for many irradiation/count trials with any number of samples, translating to significantly improved counting statistics. (author)

Activation analysis course experiments with a 14-MeV neutron generator

International Nuclear Information System (INIS)

Miller, D.A.; Miller, G.E.

1976-01-01

The use of a 14 MeV neutron generator system in the radiochemistry teaching program of the Chemistry Department of the University of California at Irvine is described. Several different types of experiment are outlined to indicate the broad applicability of such a system to an instructional program in Chemistry. The program has encompassed instruction of undergraduates, graduate students and a Summer Institute Workshop for College Professors

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

Science.gov (United States)

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

2018-04-01

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

Detecting neutrons by forward recoil protons at the Energy & Transmutation facility: Detector development and calibration with 14.1-MeV neutrons

Science.gov (United States)

Afanasev, S.; Vishnevskiy, A.; Vishnevskiy, D.; Rogachev, A.; Tyutyunnikov, S.

2017-05-01

As part of the Energy & Transmutation project, we are developing a detector for neutrons with energies in the 10-100 MeV range emitted from the target irradiated by a charged-particle beam. The neutron is detected by measuring the time-of-flight and total kinetic energy of the forward-going recoil proton [1] knocked out at a small angle from a thin layer of plastic scintillator, which has to be selected against an intense background created by γ quanta, scattered neutrons, and charged particles. On the other hand, neutron energy has to be measured over the full range with no extra tuning of the detector operation regime. Initial measurements with a source of 14.1-MeV neutrons are reported.

Determination of uranium and thorium contents using a 14 MeV neutron generator and a radiometric method

International Nuclear Information System (INIS)

Casagrande, J.A.

1981-04-01

A simple method was developed which can determine uranium and thorium in uranium ores, by 14MeV neutron activation and delayed neutron counting. The process can be used in field laboratories to select samples for processing. The method does not require a previous treatment of the samples and the analysis time is below 5 minutes. The detection limit of the method is about 2 ppm, when the yield of the 14MeV source has a value of 2 X 10 11 neutrons/second, and an optimized delayed neutron counter is used. A radiometric method is used determine separately the thorium content of the sample, and this result is combined with the activation one in order to obtain uranium content. The radiometric method in the counting of the 2,6 MeV gamma rays from 208 Tl using a NaI(Tl) detector. Delayed neutron counting is performed with BF 3 detectors inside a paraffin box. The problem of radioactive equilibrium does not affect thorium determination since the biggest activities of thorium daughters are much smaller than the times involved in the displacements of mineral which can give origin to the radioactive desequilibrium. (Author) [pt

Beam plasma 14 MeV neutron source for fusion materials development

International Nuclear Information System (INIS)

Ravenscroft, D.; Bulmer, D.; Coensgen, F.; Doggett, J.; Molvik, A.; Souza, P.; Summers, L.; Williamson, V.

1991-09-01

The conceptual engineering design and expected performance for a 14 MeV DT neutron source is detailed. The source would provide an intense neutron flux for accelerated testing of fusion reactor materials. The 150-keV neutral beams inject energetic deuterium atoms, that ionize, are trapped, then react with a warm (200 eV), dense tritium target plasma. This produces a neutron source strength of 3.6 x 10 17 n/sec for a neutron power density at the plasma edge of 5--10 MW/m 2 . This is several times the ∼2 MW/m 2 anticipated at the first wall of fusion reactors. This high flux provides accelerated end-of-life tests of 1- to 2-year duration, thus making materials development possible. The modular design of the source and the facilities are described

Combined proton-recoil and neutron time-of-flight spectrometer for 14 MeV neutrons

International Nuclear Information System (INIS)

Grosshoeg, G.; Aronsson, D.; Arvidsson, E.; Beimer, K.-H.; Pekkari, L.-O.; Rydz, R.; Sjoestrand, N.G.

1983-05-01

The main effort put into this work is the foundation of a reliable physical basis for a 12-16 MeV neutron-spectrometer at JET. The essential problem is the amount of scatterer that can be incorporated without losing resolution. We have found two possible methods, the use of a pure hydrogen scatterer and the use of a polyethylene foil scatterer. The pure hydrogen solution gives a very complicated spectrometer with large detectors. The polyethylene solution is limited by the thickness and the width of the foil. We judge the solution with the polyethylene foil to be the most promising one for a reliable spectrometer. However, a large foil area is needed. This gives a spectrometer design with an annular foil, an annular neutron detection system, and a central proton-detector. An efficiency of 10 - 6 counts/s per n/cm 2 ,s at the foil can be obtained with a resolution in the order of 100 keV for 14 MeV neutrons. Following the General Requirements given in the contract of this work, we concluded that an instrument with the desired properties can be made. The instruments is able to give useful information about the plasma from plasma temperatures of about 5 keV. (Authors)

Contribution to the study of 14 MeV neutron scattering by {sup 12}C using a time-of-flight spectrometer (1963); Contribution a l'etude de la diffusion des neutrons de 14 MeV par {sup 12}C, a l'aide d'un spectrometre a temps de vol (1963)

Energy Technology Data Exchange (ETDEWEB)

Perrin, P [Commisariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1963-07-15

Experimental measurements of 14 MeV fast neutrons scattering by {sup 12}C by time-flight spectrometer, with a 1.7 n. sec over-all resolution. The excitation of the 7.65 MeV level is observed. (author) [French] Etude experimentate de la diffusion par {sup 12}C des neutrons rapides de 14 MeV a l'aide d'un spectrometre de resolution totale de 17 n/s. Observation de l'excitation du niveau 0+ de 7,65 MeV. (auteur)

Differential cross sections for carbon neutron elastic and inelastic scattering from 8.0 to 14.5 MeV

Energy Technology Data Exchange (ETDEWEB)

Haouat, G.; Lachkar, J.; Patin, Y.; Sigaud, J.; Cocu, F.

1975-06-01

Differential elastic and inelastic cross sections for fast neutrons scattered by carbon have been measured between 8.0 and 14.5 MeV. No experimental results on {sup 12}C seem to have been reported, at this time, between 9 and 14 MeV. A complete and consistent set of data on carbon, including total, elastic and inelastic, (n,α) and (n,n'3α) cross sections, is now available for energies below 14.5MeV.

Multi-element analysis of crude-oil samples by 14.6 MeV neutron activation

International Nuclear Information System (INIS)

Cam, N.F.; Cigeroglu, F.; Erduran, M.N.

1997-01-01

The instrumental neutron activation technique, using the SAMEST T-400 neutron generator with 14.6 MeV neutrons produced from 3 H(d,n) 4 He reaction, is demonstrated for multi-element analysis of Saudi-Arabian crude-oil samples. The system parameters for the absolute method (e.g., the counting solid-angle, intrinsic efficiency of the γ-ray detector, effective neutron flux, activation cross sections, etc.)were determined and the results of elemental concentrations were presented with the corrections for all possible interferences having been carefully considered. (author)

Determination of oxygen content in steel using activation analysis with 14 MeV neutron

International Nuclear Information System (INIS)

Calado, C.E.

1978-01-01

In the quantitative analysis of oxygen in steel by fast neutron activation analysis the oxygen content is evaluated from the measured activity of 16 N produced. Steel s mples are irradiated in 14 MeV neutron flux. After irradiation the samples are pneumatically transfered to the counting terminal where activity is measured. Oxygen concentrations, are obtained by comparison with standards of specified oxygen content [pt

Measurement of the neutron and gamma-ray spectra originating from a 14-MeV neutron source in liquid nitrogen and liquid air

International Nuclear Information System (INIS)

Broecker, B.; Clausen, K.; Schneider-Kuehnle, P.; Weinert, M.

1975-01-01

An experiment to measure the radiation transport originating from a 14-MeV neutron source in liquid nitrogen and liquid air is presented. Neutron and gamma-ray spectra were measured with a proton-recoil NE 213 scintillator and with four spherical proportional counters in a tank filled with liquid nitrogen or liquid air. The neutron spectra cover the energy range of 20 keV to 18 MeV. The source-detector separation varies in the liquid medium between 60 and 240 cm. The experimental setup is briefly described and the errors are estimated. (2 tables, 9 figures) (auth)

Double-differential beryllium neutron cross sections at incident neutron energies of 5. 9, 10. 1, and 14. 2 MeV. [5. 9 to 14. 2 MeV, differential cross sections, ENDF/B-IV

Energy Technology Data Exchange (ETDEWEB)

Drake, D.M.; Auchampaugh, G.F.; Arthur, E.D.; Ragan, C.E.; Young, P.G.

1976-08-01

Beryllium neutron-production cross sections were measured using the time-of-flight technique at incident neutron energies of 5.9, 10.1, and 14.2 MeV, and at laboratory angles of 25, 27.5, 30, 35, 45, 60, 80, 100, 110, 125, and 145/sup 0/. The differential elastic and inelastic cross sections are presented. Inelastic is defined here as those reactions that proceed through the states at 1.69-, 2.43-, 2.8-, and 3.06-MeV excitation energy in /sup 9/Be. Comparison of emission energy spectra with calculations using the ENDF/B-IV beryllium cross sections shows that the ENDF/B cross sections strongly overemphasize the low lying states in /sup 9/Be.

Analysing power for neutron-proton scattering at 14.1 MeV

International Nuclear Information System (INIS)

Brock, J.E.; Chisholm, A.; Duder, J.C.; Garrett, R.; Poletti, J.L.

1981-01-01

The analysing power Asub(y)(theta) for neutron-proton scattering has been measured at 14.1 MeV for c.m. angles between 50 0 and 157 0 . A polarized neutron beam was produced by the reaction 3 H(d,n) 4 He at 110 keV, using polarized deuterons from an atomic beam polarized ion source. Liquid and plastic scintillators were used for proton targets and the scattered particles were detected in an array of platic scintillators. Use of the associated alpha technique, multi-parameter recording of events and off-line computer treatment led to very low backgrounds. The results differ significantly from the predictions of the phase-shift analyses of Yale IV, Livermore X and Arndt et al. We find, however, excellent agreement with the predictions of the Paris potential of Lacombe et al. Existing n-p analysing power results up to 30 MeV are surveyed and found to be consistent. An attempt was made to look for an isospin splitting of the triplet P-wave phase shifts. (orig.)

Calculation of 14 MeV neutron transmission

International Nuclear Information System (INIS)

Vyrskij, M.Yu.; Dubinin, A.A.; Zhuravlev, V.I.; Isaev, N.V.; Klintsov, A.A.; Krivtsov, A.S.; Linge, I.I.; Panfilov, E.I.; Prit'mov, A.P.

1979-01-01

The possibility of using the 28 group constant system (28-GCS) for calculating the transport of neutrons with initial energy of 14 MeV in thermonuclear reactor blankets is studied. A blanket project suggested by the Oak Ridge National Laboratory is used as a test version to estimate applicability of the 28-GCS. Niobium is used in a blanket as a structural material. A mixture of lithium nuclides is used for tritium production. The results of blanket test calculation and the calculational results obtained using the 28-GCS from the UKNDL library are compared. The numerical 28-group calculation of blonket is carried out by means of the ROZ-6 and ROZ-9 codes but not by the Monte-Carlo method as compared with the test calculation. Time of the blanket calculation on the BESM-6 computer by means of the ROZ-9 code in 2P 5 approximation using the 28-GCS amounts to 10 min. It is noted that to create effective codes for the numerical blanket calculation different calculational grids are necessary for different energy grups. The calculations carried out have shown the possibility of using the 28-group library of cross sections for the numerical solution of the neutron transport equation in estimating analysis of blankets

Measurement of fission cross-section for the {sup 232}Th(n,f){sup 141}Ba reaction induced by neutrons around 14 MeV

Energy Technology Data Exchange (ETDEWEB)

Lan, Chang-Lin; Fang, Kai-Hong [Lanzhou University, School of Nuclear Science and Technology, Lanzhou, Gansu Province (China); Lanzhou University, Engineering Research Center for Neutron Application, Ministry of Education, Lanzhou, Gansu Province (China); Liu, Shuang-Tong; Lv, Tao; Wang, Qiang; Zhang, Zheng-Wei [Lanzhou University, School of Nuclear Science and Technology, Lanzhou, Gansu Province (China); Lai, Cai-Feng [Chinese Academy of Engineering Physics, Institute of Nuclear Physics and Chemistry, Mianyang, Sichuan Province (China)

2016-11-15

The fission cross-section of the {sup 232}Th(n,f){sup 141}Ba reaction induced by neutrons around 14 MeV was measured precisely with the neutron activation and off-line gamma-ray spectrometric technique. Neutron fluence was monitored on-line using the accompanying α-particles from the {sup 3}H({sup 2}H,n){sup 4}He reaction, whereas the neutron energies were measured by the method of cross-section ratios of {sup 90}Zr(n,2n){sup 89}Zr to {sup 93}Nb(n,2n){sup 92m}Nb reactions. The experimentally determined {sup 232}Th(n,f){sup 141}Ba reaction cross-sections were 12.2 ± 0.4 mb at E{sub n} = 14.1 ± 0.3 MeV, 13.0 ± 0.5 mb at E{sub n} = 14.5 ± 0.3 MeV and 13.3 ± 0.5 mb at E{sub n} = 14.7 ± 0.3 MeV, respectively. (orig.)

Spectrum of neutrons leaking from an iron sphere with a central 14 MeV neutron source

International Nuclear Information System (INIS)

Borisov, A.A.; Zagryadskij, V.A.; Chuvilin, D.Yu.; Kralik, M.; Pulpan, J.; Tichy, M.

1991-01-01

Following a review of the present state of nuclear data requisite for the calculation of the transport of 14 MeV neutrons through iron of natural isotopic composition, the results are given of the calculation of the energy spectrum of such neutrons after their passage through an iron sphere 240 mm o.d. and 90 mm i.d., the neutron source being accommodated in the centre of the sphere. The calculations were made using the one-dimensional code BLANK working with the nuclear data libraries ENDL-75, ENDL-83, ENDL/B-IV, JENDL-2 and BROND, and using the three-dimensional code BRAND with the library ENDL-78. The calculated spectra were compared with the experimental spectrum measured at a distance of 3 m from the sphere by means of an NE-213 scintillator, which records reflected protons. The reflected proton spectrum was processed by the matrix method (program FORIST), and the result was normalized to one neutron emitted by the source, as were the calculated spectra. The comparison demonstrates that the experiment is best fitted by the spectrum calculated by using the library JENDL-2, where the integrals of the observed and calculated spectra over the 1-15 MeV range differ as little as approximately 10%. (author). 3 figs., 5 tabs., 16 refs

Review of neutron data: 10 to 40 MeV

Energy Technology Data Exchange (ETDEWEB)

Haight, R.C.

1977-04-01

Neutron data are reviewed for incident neutron energies between 10 and 40 MeV. A census of the data shows that there are many gaps in this range and that the existing data are primarily for neutron energies around 14 MeV. Aside from total cross sections, there are few data between 10 and 13 MeV and between 15 and 40 MeV. Examples are presented to show the quality of selected data for total, elastic, inelastic, activation, and charged-particle and gamma-ray production cross sections. The spectra of emitted particles are also discussed.

Review of neutron data: 10 to 40 MeV

International Nuclear Information System (INIS)

Haight, R.C.

1977-04-01

Neutron data are reviewed for incident neutron energies between 10 and 40 MeV. A census of the data shows that there are many gaps in this range and that the existing data are primarily for neutron energies around 14 MeV. Aside from total cross sections, there are few data between 10 and 13 MeV and between 15 and 40 MeV. Examples are presented to show the quality of selected data for total, elastic, inelastic, activation, and charged-particle and gamma-ray production cross sections. The spectra of emitted particles are also discussed

Secondary gamma-ray skyshine from 14 MeV Neutron Source Facility (OKTAVIAN). Comparison of measurement with its simulation

Energy Technology Data Exchange (ETDEWEB)

Morotomi, Ryutaro; Kondo, Tetsuo; Murata, Isao; Yoshida, Shigeo; Takahashi, Akito [Osaka Univ., Department of Nuclear Engineering, Suita, Osaka (Japan); Yamamoto, Takayoshi [Osaka Univ., Radio Isotope Research Center, Suita, Osaka (Japan)

2000-03-01

Measurement of secondary gamma-ray skyshine was performed at the Intense 14 MeV Neutron Source Facility (OKTAVIAN) of Osaka University with NaI and Hp-Ge detectors. From the result of measurements, some mechanism of secondary gamma-ray skyshine from 14 MeV neutron source facility was found out. The analysis of the measured result were carried out with MCNP-4B for four nuclear data files of JENDL-3.2, JENDL-F.F., FENDL-2, and ENDF/B-VI. It was confirmed that all the nuclear data are fairly reliable for calculations of secondary gamma-ray skyshine. (author)

Fast neutron (14.5 MeV) radiography: a comparative study

International Nuclear Information System (INIS)

Klann, R.T.

1996-01-01

Fast neutron (14.5 MeV) radiography is a type of non-destructive analysis tool that offers its own benefits and drawbacks. Because cross-sections vary with energy, a different range of materials can be examined with fast neutrons than can be studied with thermal neutrons, epithermal neutrons, or x-rays. This paper details these differences through a comparative study of fast neutron radiography to the other types of radiography available. The most obvious difference among the different types of radiography is in the penetrability of the sources. Fast neutrons can probe much deeper and can therefore obtain details of the internals of thick objects. Good images have been obtained through as much as 15 cm of steel, 10 cm of water, and 15 cm of borated polyethylene. In addition, some objects were identifiable through as much as 25 cm of water or 30 cm of borated polyethylene. The most notable benefit of fast neutron radiography is in the types of materials that can be tested. Fast neutron radiography can view through materials that simply cannot be viewed by X rays, thermal neutrons, or epithermal neutrons due to the high cross-sections or linear attenuation coefficients involved. Cadmium was totally transparent to the fast neutron source. Fast neutron radiography is not without drawbacks. The most pronounced drawback has been in the quality of radiograph produced. The image resolution is only about 0.8 mm for a 1.25 cm thick object, whereas, other forms of radiography have much better resolution

Use of the SPIRAL 2 facility for material irradiations with 14 MeV energy neutrons

International Nuclear Information System (INIS)

Mosnier, A.; Ridikas, D.; Ledoux, X.; Pellemoine, F.; Anne, R.; Huguet, Y.; Lipa, M.; Magaud, P.; Marbach, G.; Saint-Laurent, M.G.; Villari, A.C.C.

2005-01-01

The primary goal of an irradiation facility for fusion applications will be to generate a material irradiation database for the design, construction, licensing and safe operation of a fusion demonstration power station (e.g., DEMO). This will be achieved through testing and qualifying material performance under neutron irradiation that simulates service up to the full lifetime anticipated in the power plant. Preliminary investigations of 14 MeV neutron effects on different kinds of fusion material could be assessed by the SPIRAL 2 Project at GANIL (Caen, France), aiming at rare isotope beams production for nuclear physics research with first beams expected by 2009. In SPIRAL 2, a deuteron beam of 5 mA and 40 MeV interacts with a rotating carbon disk producing high-energy neutrons (in the range between 1 and 40 MeV) via C (d, xn) reactions. Then, the facility could be used for 3-4 months y -1 for material irradiation purposes. This would correspond to damage rates in the order of 1-2 dpa y -1 (in Fe) in a volume of ∼10 cm 3 . Therefore, the use of miniaturized specimens will be essential in order to effectively utilize the available irradiation volume in SPIRAL 2. Sample package irradiation temperature would be in the range of 250-1000 deg. C. The irradiation level of 1-2 dpa y -1 with 14 MeV neutrons (average energy) may be interesting for micro-structural and metallurgical investigations (e.g., mini-traction, small punch tests, etc.) and possibly for the understanding of specimen size/geometric effects of critical material properties. Due to the small test cell volume, sample in situ experiments are not foreseen. However, sample packages would be, if required, available each month after transfer in a special hot cell on-site

Analysis of oxygen content in steel by means of 14 MeV neutrons

International Nuclear Information System (INIS)

Chuang, L.S.; Wong, K.C.; Chiu, W.Y.

1975-01-01

A sealed-tube type 14 MeV neutron generator with maximum neutron output of 10 11 n/sec, incorporating a pneumatic sample transfer system of single-tube type and with a single rotation of the sample during neutron irradiation, is used to develop a method suitable for routine work in industrial applications. A pulse shape analyser system incorporating an organic scintillation detector is used for monitoring neutron flux level during the neutron irradiation of the sample. Polyethylene, of oxygen content 163 ppm determined by comparison with lucite, is used as the steel sample carrier. A 3 x 3 in. NaI(Tl) crystal is used with a single channel analyser to count the 6.1 and 7.1 MeV gamma rays emitted from 16 N as a result of the reaction 16 O(n,p) 16 N. As the present activation analysis makes use of the comparison method, a steel-mylar standard made of layered steel and mylar discs is prepared and a calibration curve constructed. A method of correcting the oxygen contribution in the polyethylene sample carrier is devised and the content of oxygen in the steel standard is determined. A survey of neutron flux distribution is also attempted and it is found that nearly symmetrical distribution of the flux, about the centre of the sample carrier which is placed with its axis in parallel to the plane of the disc-shaped target of the neutron-generating tube, is far from being flat. (Auth.)

Cross-sections for formation of {sup 89}Zr{sup m} through {sup 90}Zr(n,2n){sup 89}Zr{sup m} reaction over neutron energy range 13.73 MeV to 14.77 MeV

Energy Technology Data Exchange (ETDEWEB)

Attar, F.M.D. [Department of Physics, University of Pune, Pune-411007 (India); Mandal, R. [Department of Physics, University of Pune, Pune-411007 (India); Indian Institute of Technology, Kharagpur (India); Dhole, S.D. [Department of Physics, University of Pune, Pune-411007 (India); Saxena, A. [Nuclear Physics Division, BARC, Mumbai (India); Ashokkumar,; Ganesan, S. [Reactor Physics Design Division, BARC, Mumbai (India); Kailas, S. [Nuclear Physics Division, BARC, Mumbai (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune-411007 (India)], E-mail: vnb@physics.unipune.ernet.in

2008-04-01

The cross-sections for formation of metastable state of {sup 89}Zr ({sup 89}Zr{sup m}, 0.588 MeV, 4.16 m) through {sup 90}Zr(n,2n){sup 89}Zr{sup m} reaction induced by 13.73 MeV to 14.77 MeV neutrons were measured for the first time and also theoretically estimated using Empire-II and Talys programs. At 13.73 MeV neutron energy, the {sup 89}Zr nuclei can be excited to metastable state, {sup 89}Zr{sup m}, when the first and the second emitted neutrons have energies lower than the most probable energy {approx}0.64 MeV. The probability of exciting {sup 89}Zr nuclei to energy levels higher than 0.588 MeV and therefore of populating the metastable state through decay process increases with increasing neutron energy. The measured cross-sections vary from 41{+-}3mb to 221{+-}15mb over neutron energies 13.73 MeV to 14.77 MeV, and are in agreement with the cross-sections estimated using Empire-II code. The formation of {sup 89}Zr{sup m} is favoured when the first and the second reaction neutrons are emitted with the most probable energies rather than lower energy, except for 13.73 MeV neutrons.

Radiography studies with gamma rays produced by 14-MeV fusion neutrons

International Nuclear Information System (INIS)

Smith, D.L.; Ikeda, Yujiro; Uno, Yoshitomo

1996-01-01

Oxygen contained in pure water has been activated via the 16 O(n, p) 16 N reaction using 14-MeV neutrons produced at a neutron generator with the 3 H(d,n) 4 He source. Photons of 6.129 and 7.115 MeV, generated by the decay of 7.13-second 16 N, were then used to demonstrate the feasibility of employing highly penetrating, nearly monoenergetic gamma rays for radiography studies of thick, dense objects composed of elements with medium to relatively high atomic numbers. A simple radiography apparatus was constructed by circulating water continuously between a position near the target of the neutron generator and a remote location where photon transmission measurements were conducted. A sodium iodide scintillator was employed to detect the photons. Pulses equivalent to photon energies smaller than 2.506 MeV (corresponding to the cascade sum of 1.333- and 1.173-MeV gamma rays from the decay of 5.271-year 60 Co) were rejected by the electronics settings in order to reduce background and improve the signal-to-noise (S/N) ratio. Respectable S/N ratios on the order of 20-to-1 were achieved with this setup. Most of the background (N) could be attributed to ambient environmental radiation and cosmic-ray interactions with the lead shielding and detector. Four representative objects were examined by photon radiography in this study. This demonstrated how such - interesting features as hidden holes and discontinuities in atomic number could be easily identified from observed variations in the intensity of transmitted photons. Some advantages of this technique are described, and potential applications are suggested for a future scenario where fusion reactors are used to generate electric power and very intense sources of high-energy photons from 16 N decay are continuously available as a byproduct of the reactor cooling process

Study of associated gamma from niobium under 14. 9 MeV neutron bombardments

Energy Technology Data Exchange (ETDEWEB)

Zhou Hongyu; Yan Yiming; Fan Guoying; Lan Liqiac; Sun Suxu; Wang Qi; Hua Ming; Han Chongzhen; Liu Shuzhenn; Rong Yaning; and others

1989-02-01

The gamma ray spectra from niobium under 14.9 MeV neutron bombardments were measured by means of a pulsed /ital T/(/ital d/, /ital n/)/sup 4/He neutron source, associated particle method, Ge(Li) detector and time-of-flight technique at 7 angles between 30/degree/ and 140/degree/. 79 gamma lines were determined by a high resolution gamma spectrum analysis program, and reaction types and transition levels of 62 lines were roughly assigned. There were 40 ones of 79 lines, which were first found in reactions induced by neutrons. The differential cross sections of every gamma line at 7 angles were determined. It is shown that associated gamma ray emissions from this reaction are basically isotropic.

Design status of an intense 14 MeV neutron source for cancer therapy

CERN Document Server

Yao, Z E; Cheng, S W; Jia, W B

2002-01-01

Design and development of an intense 14 MeV neutron source for cancer therapy is in progress at the Institute of Nuclear Research of Lanzhou University. The neutrons from the T(d,n) sup 4 He reaction are produced by bombarding a rotating titanium tritide target with a 40 mA deuteron beam at 600 keV. The designed neutron yield is 8x10 sup 1 sup 2 n/s and the maximum dose rate at a 100 cm source-to-skin distance is 25 cGy/min. The HV terminal, accelerating column and HV power supply are enclosed inside a stainless steel pressure vessel containing 6 atm SF sub 6 gas to provide the electrical insulation.

The sensitivity of RTL, RPL and photographic detectors to 14.7MeV neutrons

International Nuclear Information System (INIS)

Spurny, Frantisek; Medioni, Roger; Portal, Guy.

1975-08-01

The sensitivity of various types of γ detectors to neutrons should be known for a better dosimetry of electromagnetic radiations in neutron fields. The sensitivity of various types of detectors to 14.7MeV neutrons was studied using RTL (LiF, 7 LiF, Ca SO 4 : Dy Al 2 O) RPL (C.E.C. glasses) and photographic detectors (Kodak-Pathe dosemeters). The methods used for the determination of the neutron and photon mixed field are described and the effect of containers and packing on the accuracy of results was investigated. For each detector studied the specific sensitivity to neutrons (sensitivity of the product alone) and the apparent sensitivity in usual operating conditions (action of surrounding materials) is given [fr

Production cross section measurement of discrete gammas-ray at 90 degree for interactions of 14. 9 MeV neutrons with carbon and niobium

Energy Technology Data Exchange (ETDEWEB)

Zhou Hongyu; Yan Yiming; Tang lin; Wen Chenlin; Zhang Shenji; Hua Ming; Han Chongzhan; Ding Xiaoji; Lan Liqiao; Fan Guoying; Yan Hua; Wang Xingfu; Wang Qi; Sun Suxu; Rong Yaning; Liu Shuzhen (Institute of Low Energy Nuclear Physics, Beijing Normal University, Beijing (CN))

1989-05-01

The cross sections of discrete gamma-ray produced by interactions of 14.9 MeV neutrons with carbon and niobium were investigated. A pulsed {ital T}({ital d},{ital n}){sup 4} He neutron source was used in the measurement. Neutron flux incident upon the sample was determined with the associated particle method. Technique of time-of-flight was used for reducing the background. A new method to calculate neutron flux attenuation in large cylindrical sample was proposed. The split of 4.439 MeV gamma-ray line from {sup 12}C({ital n},{ital n}{prime}{gamma}){sup 12}C reactions was confirmed. 79 discrete gamma-ray lines and their production cross sections for the interactions of 14.9 MeV neutrons with niobium were obtained for the first time.

Increase of the electrical resistance of thin aluminium film due to 14 MeV neutron irradiation

Energy Technology Data Exchange (ETDEWEB)

Agrawal, S K; Kumar, U; Singh, S P; Bhattacharya, S; Nigam, A K [Banaras Hindu Univ. (India). Dept. of Physics

1978-01-01

The effect of 14 MeV neutron bombardment on the electrical resistance of 500 A thick vacuum-coated Al film is investigated. In the beginning, a slow, then sharp and finally again slow increase is observed in the electrical resistance of the film. Transmission electron micrographs of the film after the same dose of neutron irradiation show a large number of defects produced in the film due to neutron irradiation, which seems to be the cause of this increase.

Comparison of 14 MeV neutron activation analysis and competitive methods for determination of oxygen, nitrogen, silicon, fluorine and other elements

International Nuclear Information System (INIS)

Bild, R.W.

1986-01-01

14 MeV neutron activation analysis (14 MeV NAA) makes use of small particle accelerators to produce 14 MeV neutrons from the D-T reaction. The neutrons produce radioactive isotopes in samples by the reactions (n,p), (n,2n) and (n,α). Gamma rays emitted are counted to determine the amount of the target element present. Major applications have been determination of total O, N or Si in solid and liquid matrices, but the technique can also be applied to determine concentrations of about 30 other elements including F, Cl, Al, P and Mg. Detection limits are a few micrograms in the best cases and milligrams for most others. The method has advantages of being nondestructive, fast and insensitive to sample inhomogeneities. It lends itself especially well to sequential analysis of the same sample by several techniques and to samples that are difficult to dissolve. Portable generators have been applied to industrial situations and to well logging. Major disadvantages are the necessity to house a radiation producing instrument, the cost of the equipment and the lack of useful neutron reactions for some important elements. Accuracy (typically +-7 to 10% relative) and precision (+-1 to 5% relative) are comparable to competing techniques. For determination of low levels of O and N in most metals inert gas fusion is more rapid and sensitive; elemental analyzer is more sensitive for O and N in organics. Wet chemical methods rarely have any advantage over 14 MeV NAA for solid samples when concentrations are in the detection limit range of the 14 MeV NAA methods. Future developments in the field will come in the areas of simpler, more portable and higher neutron output generator designs. 66 refs

Neutronics experiments for uncertainty assessment of tritium breeding in HCPB and HCLL blanket mock-ups irradiated with 14 MeV neutrons

International Nuclear Information System (INIS)

Batistoni, P.; Angelone, M.; Pillon, M.; Villari, R.; Fischer, U.; Klix, A.; Leichtle, D.; Kodeli, I.; Pohorecki, W.

2012-01-01

Two neutronics experiments have been carried out at 14 MeV neutron sources on mock-ups of the helium cooled pebble bed (HCBP) and the helium cooled lithium lead (HCLL) variants of ITER test blanket modules (TBMs). These experiments have provided an experimental validation of the calculations of the tritium production rate (TPR) in the two blanket concepts and an assessment of the uncertainties due to the uncertainties on nuclear data. This paper provides a brief summary of the HCPB experiment and then focuses in particular on the final results of the HCLL experiment. The TPR has been measured in the HCLL mock-up irradiated for long times at the Frascati 14 MeV Neutron Generator (FNG). Redundant and well-assessed experimental techniques have been used to measure the TPR by different teams for inter-comparison. Measurements of the neutron and gamma-ray spectra have also been performed. The analysis of the experiment, carried out by the MCNP code with FENDL-2.1 and JEFF-3.1.1 nuclear data libraries, and also including sensitivity/uncertainty analysis, shows good agreement between measurements and calculations, within the total uncertainty of 5.9% at 1σ level. (paper)

Lithium Blanket Module dosimetry measurements at the LOTUS 14-MeV neutron source facility

International Nuclear Information System (INIS)

Tsang, F.Y.; Leo, W.R.; Sahraoui, C.; Wuthrich, S.; Harker, Y.D.

1986-01-01

This paper describes the measurements and results of the dosimeter material reaction rates inside the Lithium Blanket Module (LBM) after irradiation by the LOTUS 14-MeV neutron source at the Ecole Polytechnique Federale de Lausanne. The measurement program has been designed to utilize sets of passive dosimeter materials in the form of foils and wires. The dosimetry materials reaction thresholds and interaction response ranges chosen for this series of measurements encompass the entire neutron spectra along the full length of the LBM fuel rods

Measurement and analysis of 14 MeV neutron-induced double-differential neutron emission cross sections needed for fission and fusion reactor technology

International Nuclear Information System (INIS)

Wang Dahai.

1990-10-01

The main objectives of this IAEA Co-ordinated Research Programme are to improve the data on 14 MeV neutron-induced double-differential neutron emission cross sections for materials needed for fission and fusion reactor technology. This report summarizes the conclusions and recommendations which were agreed by all participants during the Second Research Co-ordination Meeting

Standard Test Method for Oxygen Content Using a 14-MeV Neutron Activation and Direct-Counting Technique

CERN Document Server

American Society for Testing and Materials. Philadelphia

2007-01-01

1.1 This test method covers the measurement of oxygen concentration in almost any matrix by using a 14-MeV neutron activation and direct-counting technique. Essentially, the same system may be used to determine oxygen concentrations ranging from over 50 % to about 10 g/g, or less, depending on the sample size and available 14-MeV neutron fluence rates. Note 1 - The range of analysis may be extended by using higher neutron fluence rates, larger samples, and higher counting efficiency detectors. 1.2 This test method may be used on either solid or liquid samples, provided that they can be made to conform in size, shape, and macroscopic density during irradiation and counting to a standard sample of known oxygen content. Several variants of this method have been described in the technical literature. A monograph is available which provides a comprehensive description of the principles of activation analysis using a neutron generator (1). 1.3 The values stated in either SI or inch-pound units are to be regarded...

Use of 14 MeV neutrons in activation analysis. Experiments carried out at the Grenoble nuclear research Centre (1963); Utilisation de neutrons de 14 MeV en analyse par activation. Experience realisee au Centre d'etudes nucleaires de Grenoble (1963)

Energy Technology Data Exchange (ETDEWEB)

Auboin, G; Guazzoni, P; Laverlochere, J [Commisariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1963-07-01

The use of 14 MeV neutron irradiation makes it possible to extend the field of application of activation analysis to elements which cannot be activated in nuclear reactors (oxygen, boron, for example) or else to consider the possibility of 'portable' measurement units for routine analyses. With this aim, tests have been carried out for studying the sensitivity and interferences in the case of the dosing of oxygen in eleven different matrices using 150 and 300 kV SAMES accelerators producing 14 MeV neutrons by the reaction {sup 3}H (d, n) {sup 4}He. The sensitivity of the dosage methods for six writer elements has also been studied. The results obtained show that, for a neutron flux of 10{sup 10} n/4{pi}, the sensitivities vary from 100 {mu}g and 1 mg for oxygen in nine matrices (Be, Ta, Nb, Ti, Zr, Fe, Al, Sb, Si) and that it is possible to dose the six elements F, B, Y, Si, N, Al with sensitivities of between 1 an 1000 micrograms. (authors) [French] L'irradiation au moyen de neutrons de 14 MeV permet d'etendre le domaine d'application de l'analyse par activation a des elements non activables en reacteur nucleaire (oxygene, bore, par exemple) ou encore d'envisager des unites de dosage ''portables'' pour des analyses de routine. Dans ce but, des essais ont ete effectues pour etudier les sensibilites et les interferences dans le cas du dosage de l'oxygene dans onze matrices differentes, au moyen d'accelerateurs SAMES 150 et 300 kV. produisant les neutrons de 14 MeV par la reaction {sup 3}H (d, n) {sup 4}He. Des sensibilites de dosage ont egalement ete etudiees pour six autres elements. Les resultats obtenus montrent que, pour un flux de neutrons de 10{sup 10} n /4{pi}, les sensibilites varient entre 100 {mu}g et 1 mg, pour l'oxygene dans neuf matrices (Be, Ta, Nb, Ti, Zr, Fe, Al, Sb, Si) et qu'il est possible de doser les six elements F, B, Y, Si, N, Al avec des sensibilites se situant entre 1 et 1000 microgrammes. (auteurs)

Kerma factors for neutrons of 14 MeV to 60 MeV in elemental H, C, N and O

Energy Technology Data Exchange (ETDEWEB)

Behrooz, M.A.; Watt, D.E. (Dundee Univ. (UK). Dept. of Medical Biophysics)

1981-01-01

Total kerma factors, and partial kerma factors for production of specified charged H and He particles and heavier recoils, have been computed using basic theoretical and experimental nuclear data for neutrons at energies between 14 MeV and 60 MeV in the main tissue elements and in ICRU muscle tissue. All the more recent computations of total kerma factors, along with those determined from direct experimental measurements of partial kerma factors, now form a reasonably consistent set of data enabling average total kerma factors with coefficients of better than 3% for hydrogen, 16% for carbon, 23% for nitrogen and 9% for oxygen to be recommended for application to medical dosimetry and radiation protection. Total kerma factors for ICRU muscle tissue have a precision of better than 2.5% over the neutron energy range considered. Although there is adequate precision for total kerma factors for soft tissue, nevertheless analysis of the partial kerma factors indicates that caution must be exercised in use of the information for quality specification, e.g. in microdose spectra, and that more detailed basic reaction data is required for fast neutrons.

Determination of the emission rate for the 14 MeV neutron generator with the use of radio-yttrium

OpenAIRE

Laszynska Ewa; Jednorog Slawomir; Ziolkowski Adam; Gierlik Michal; Rzadkiewicz Jacek

2015-01-01

The neutron emission rate is a crucial parameter for most of the radiation sources that emit neutrons. In the case of large fusion devices the determination of this parameter is necessary for a proper assessment of the power release and the prediction for the neutron budget. The 14 MeV neutron generator will be used for calibration of neutron diagnostics at JET and ITER facilities. The stability of the neutron generator working parameters like emission and angular homogeneity affects the accu...

Measurement of leakage neutron spectra from a spherical pile of zirconium irradiated with 14MeV neutrons and validation of its nuclear data

CERN Document Server

Ichihara, C; Hayashi, S A; Yamamoto, J; Takahashi, A

2003-01-01

In order to make a benchmark validation of the nuclear data for Zr, the leakage neutron spectrum from a Zr sphere of a 61-cm diameter was measured between 0.1 and 16MeV using a time-of-flight technique with a 14MeV neutron source facility, OKTAVIAN. The result was compared with the calculation using the Monte Carlo code MCNP-4A. To investigate the spectrum dependence on the individual neutron reactions, test calculations were carried out with the MCNP-4A code using the JENDL-3.2-based libraries, in which partial cross section values were reduced from the original values. From the comparison between the measured and the calculated spectra, it was found that each of the results could predict well the experiment in general. However, in detail, both ENDF/B-VI and EFF-2.4 gave considerable overestimation above 1 MeV. The JENDL-3.2 predicts the spectrum almost satisfactorily except below 0.8 MeV and around 10 MeV. The discrepancy found in JENDL-3.2 calculation is considered due to the cross section values of the (n...

Measurement of the fission cross-section ratio for 237Np/235U around 14 MeV neutron energies

International Nuclear Information System (INIS)

Desdin, L.; Szegedy, S.; Csikai, J.

1989-01-01

Fission cross-section ratio was determined for 237 Np/ 235 U around 14 MeV neutron energies with a back-to-back ionization chamber. Neutrons were produced by a 180 KV accelerator using T(d,n) 4 He reaction. No significant energy dependence was found in the cross section ratio

Cross section measurement for (n,n{alpha}) reactions by 14 MeV neutrons

Energy Technology Data Exchange (ETDEWEB)

Kasugai, Y.; Ikeda, Y.; Uno, Y. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Yamamoto, H.; Kawade, K.

1997-03-01

Nine (n,n{alpha}) cross sections for (n,n{alpha}) reactions induced by 13.5-14.9 MeV neutrons were measured for {sup 51}V, {sup 65}Cu, {sup 71}Ga, {sup 76}Ge, {sup 87}Rb, {sup 91}Zr, {sup 93}Nb, {sup 96}Zr and {sup 109}Ag isotopes by using Fusion Neutronics Source (FNS) at JAERI. The reactions for 91Zr and 96Zr were measured for the first time. The evaluated data of JENDL-3 and ENDF/B-VI were compared with the present data. Some of the evaluated values are much different from our data by a factor more than ten. (author)

Non-destructive analysis of major components in plant materials by mean of 14-MeV neutrons; Analyse ''non destructrice'' des principaux constituants de la matiere vegetale apres irradiation aux neutrons de 14 MeV

Energy Technology Data Exchange (ETDEWEB)

Garrec, J P [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1968-07-01

Although reactors are an important source of neutrons for activation analysis, it is sometimes convenient to have recourse to other, less expensive neutron sources. The Centre d'Etudes Nucleaires at Grenoble has small electrostatic accelerators which generate fast neutrons of 14 MeV energy. These SAMES-type generators are used for directing a deuton beam at 150 kV onto a tritiated target, the resulting flux of monoenergetic neutrons attaining 5 x 10{sup 11} ns{sup -1} in 4 {pi} geometry by the {sup 3}H(d,n){sup 4}He reaction. Numerous elements found in plant material can be activated in this flux, mainly by (n,p), (n,{alpha}) and (n,2n) reactions. Current research is directed towards making use of the entire gamma spectrum of activated plant matter. A computer is used to break down the spectrum into seven main spectral regions by the least-squares method. As a first approximation, these regions are those obtained from aluminium, calcium, potassium, magnesium, phosphorus, silicon and chlorine standards in standard activation and radioactive decay conditions. The wanted advantage of this way of analysis is not acute sensibility, but great fastness. Therefore radioactivation with 14 MeV neutrons is particularly well adapted to quick and simultaneous dosages of useful elements in agronomy. (author) [French] Bien que les reacteurs constituent une source de neutrons importante en analyse par activation, il est parfois commode de recourir a d'autres sources neutronigenes exigeant un investissement moindre. Le Centre d'Etudes Nucleaires de Grenoble dispose de petits accelerateurs electrostatiques generateurs de neutrons rapides de 14 MeV. Ces generateurs, de type SAMES, accelerent un faisceau de deutons sous 150 kV vers une cible tritiee. Celle-ci fournit un flux de neutrons mono-energetiques atteignant 5 x 10{sup 11} n/s/4 {pi} par la reaction {sup 3}H(d,n){sup 4}He. De nombreux elements composant les matieres vegetales s'activent dans ce flux principalement par reactions

Reduction in 14 MeV neutron generation rate by ICRF injection in D-3He burning plasmas

International Nuclear Information System (INIS)

Matsuura, Hideaki; Nakao, Yasuyuki

2004-01-01

The triton distribution function during ion cyclotron range of frequency (ICRF) waves injection in D- 3 He plasmas is examined by solving the 2-dimensional Fokker-Planck equation. Triton distribution function originally has a non-Maxwellian (tail) component around 1.01 MeV birth energy range due to D(d,p)T fusion reaction. Owing to the extension of the original tail by ICRF injection, the high-energy resonance tritons further increase, and the velocity-averaged T(d,n) 4 He fusion reaction rate coefficient, i.e. 14 MeV neutron generation rate, decreases from the values when triton is assumed to be Maxwellian. It is shown that when tritons absorb ∼1/200 of the fusion power from the waves in typical D- 3 He plasma, i.e. T=80 keV, n D =2x10 20 m -3 , τ E0 =3 sec and B=6T, the 14 MeV neutron generation rate is reduced by about ∼20% from the values for Maxwellian plasmas. (author)

Measurement and calculation of neutron leakage spectra from slab samples of beryllium, gallium and tungsten irradiated with 14.8 MeV neutrons

Science.gov (United States)

Nie, Y. B.; Ruan, X. C.; Ren, J.; Zhang, S.; Han, R.; Bao, J.; Huang, H. X.; Ding, Y. Y.; Wu, H. C.; Liu, P.; Zhou, Z. Y.

2017-09-01

In order to make benchmark validation of the nuclear data for gallium (Ga), tungsten (W) and beryllium (Be) in existing modern evaluated nuclear data files, neutron leakage spectra in the range from 0.8 to 15 MeV from slab samples were measured by time-of-flight technique with a BC501 scintillation detector. The measurements were performed at China Institute of Atomic Energy (CIAE) using a D-T neutron source. The thicknesses of the slabs were 0.5 to 2.5 mean free path for 14.8 MeV neutrons, and the measured angles were chosen to be 60∘ and 120∘. The measured spectra were compared with those calculated by the continuous energy Monte-Carlo transport code MCNP, using the data from the CENDL-3.1, ENDF/B-VII.1 and JENDL-4.0 nuclear data files, the comparison between the experimental and calculated results show that: The results from all three libraries significantly underestimate the cross section in energy range of 10-13 MeV for Ga; For W, the calculated spectra using data from CENDL-3.1 and JENDL-4.0 libraries show larger discrepancies with the measured ones, especially around 8.5-13.5 MeV; and for Be, all the libraries led to underestimation below 3 MeV at 120∘.

Conceptual Design of a 14-MeV D-T Neutron Source for Material Inspection

International Nuclear Information System (INIS)

Kim, Jin-Choon; Oh, Byung-Hoon

2007-01-01

There is a worldwide need for the efficient inspection of cargo containers at airports, seaports and border crossings. And there is also a growing need for nondestructive inspection of metal objects such as airplane parts. The limitations of X-ray systems for the detection of explosives, drugs, and thick metal structures have stimulated interest in neutron radiograph or tomography. The weak link in such applications is the neutron source. The ideal neutron source should provide a high intensity, high-energy for sufficient penetration and activation, a reliable long-term operation, and a monoenergetic neutron beam. In this paper, we describe a conceptual design of a DT fusion neutron source (monoenergetic 14 MeV neutron generator) which satisfies the fore-mentioned requirements. The current design is based upon the actually proven system using the drive-in target principle. The design is versatile enough to accommodate various applications, ranging from material inspection and explosive interrogation to medical probing and cancer treatment

Quantitative comparison between experimental and simulated gamma-ray spectra induced by 14 MeV tagged neutrons

Energy Technology Data Exchange (ETDEWEB)

Perot, B., E-mail: bertrand.perot@cea.fr [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); El Kanawati, W.; Carasco, C.; Eleon, C. [CEA, DEN, Cadarache, Nuclear Measurement Laboratory, F-13108 Saint-Paul-lez-Durance (France); Valkovic, V. [A.C.T.d.o.o., Prilesje 4, 10000 Zagreb (Croatia); Sudac, D.; Obhodas, J. [Ruder Boskovic Institute, Bijenicka c. 54, 10000 Zagreb (Croatia); Sannie, G. [CEA, LIST, Saclay, F-91191 Gif-sur-Yvette (France)

2012-07-15

Fast neutron interrogation with the associated particle technique can be used to identify explosives in cargo containers (EURITRACK FP6 project) and unexploded ordnance on the seabed (UNCOSS FP7 project), by detecting gamma radiations induced by 14 MeV neutrons produced in the {sup 2}H({sup 3}H,{alpha})n reaction. The origin of the gamma rays can be determined in 3D by the detection of the alpha particle, which provides the direction of the opposite neutron and its time-of-flight. Gamma spectroscopy provides the relative counts of carbon, nitrogen, and oxygen, which are converted to chemical fractions to differentiate explosives from other organic substances. To this aim, Monte Carlo calculations are used to take into account neutron moderation and gamma attenuation in cargo materials or seawater. This paper presents an experimental verification that C, N, and O counts are correctly reproduced by numerical simulation. A quantitative comparison is also reported for silicon, iron, lead, and aluminium. - Highlights: Black-Right-Pointing-Pointer Gamma-ray spectra produced by 14 MeV neutrons in C, N, O, Si, Al, Fe, and Pb elements. Black-Right-Pointing-Pointer Quantitative comparison with MCNPX simulations using the ENDF/B-VII.0 library. Black-Right-Pointing-Pointer C, N, and O counts correctly reproduced and chemical proportions recovered using calculation. Black-Right-Pointing-Pointer Application to the detection of explosives or illicit drugs in cargo containers.

A Project for High Fluence 14 MeV Neutron Source

CERN Document Server

Pillon, Mario; Pizzuto, Aldo; Pietropaolo, Antonino

2014-01-01

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

Experimental study of the interaction of 14-MeV neutrons with 238U

International Nuclear Information System (INIS)

Voignier, J.

1968-01-01

A study has been made of the interaction of fast neutrons with natural uranium from the experimental point of view over a wide energy range. The scattering energy spectra have been obtained by the time-of-flight method developed during previous work. The cross-section σ t , the elastic cross-section σ e , and the inelastic neutron emission cross-section σ ne have been measured at 14 MeV. The average number, η, of neutrons produced by interaction is deduced from this last measurement. The experimental results are analyzed in the second part of the report. The fission spectrum and the evaporation spectrum have been deduced from the energy spectrum of the secondary neutrons. The energy spectrum of the inelastic neutrons is represented by a relationship of the type:N (E) = A E exp (-E/T e ) + B √ E exp (-E/T f )/. The parameter A, B, T e and T f have been evaluated. Finally the values obtained for the various cross sections are compared with previous results. (author) [fr

Pb(n,2n) cross section at 14.1 MeV

International Nuclear Information System (INIS)

Zhou Delin

1991-01-01

Pb is a potential candidate for the neutron multiplier of the fusion reactor, so its (n, 2n) cross section at 14 MeV is of importance. This work is carried out to get a new evaluation of Pb (n,2n) cross section at 14.1 MeV for checking the angle-integrated neutron emission cross section. The equal weight averaged value 2252 +- 40 Mb is adopted in the evaluation

Critical study of some soft-tissue equivalent material. Sensitivity to neutrons of 1 keV to 14 MeV; Etude critique de quelques materiaux equivalents aux tissus mous. Sensibilite aux neutrons de 1 keV a 14 MeV

Energy Technology Data Exchange (ETDEWEB)

Kerviler, H de; Pages, L; Tardy-Joubert, Ph [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1965-07-01

Authors have studied the elastic and inelastic reactions on various elements contribution to kerma in standard soft tissue and as a function of neutron energy from 1 keV to 14 MeV the ratio of kerma in tissue equivalent material to kerma in soft tissue. The results of calculations are made for materials without hydrogen in view to state exactly their neutron sensitivity and for the following hydrogenous materials: Rossi and Failla plastic, MixD, pure polyethylene and a new CEA tissue equivalent (a magnesium fluoride and polyethylene compound). Results for {gamma}-rays are given. (authors) [French] Les auteurs ont etudie la contribution au kerma total des reactions elastiques et inelastiques sur les divers composants du tissu mou standard et la variation, en fonction de l'energie des neutrons de 1 keV a 14 MeV, du rapport des kermas dans differents materiaux equivalents au tissu au kerma dans les tissus mous. Les materiaux etudies sont des materiaux sans hydrogene afin de preciser leur sensibilite aux neutrons et les materiaux hydrogenes suivants: plastique de Rossi et Failla, polyethylene pur, MixD, nouveau plastique CEA a base de polyethylene et de fluorure de magnesium. Les resultats pour les photons sont egalement rappeles. (auteurs)

Preliminary microstructural characterization by transmission electron microscopy of 14 MeV neutron irradiated type 316 stainless steel

International Nuclear Information System (INIS)

Echer, C.J.

1977-01-01

Substantial changes in the mechanical properties of 316 stainless steel were observed after neutron irradiation (phi/sub t/ = 2.3 x 10 21 n/m 2 and E = 14 MeV) at 25 0 C. Comparison of microstructures of the unirradiated and neutron irradiated materials were evaluated using transmission electron microscopy. Evidence of small defect clusters in the irradiated material was found. These findings are consistent with other investigators also evaluating low dose irradiations

Survival of germinal cells of the male rat after exposure to 14 and 50 MeV neutrons and R.B.E

International Nuclear Information System (INIS)

Lemaire, Guy; Grillon, Gerard; Ricourt, Alain.

1977-10-01

No significant differences could be demonstrated between male rat germinal cell survivals to 14MeV and up to 50 MeV neutrons respectively. The survivals are well fitted by an exponential model (D 0 =289 rads) logically situated between the models concerning 60 Co gamma rays and fission neutrons. On the basis of the testes weight loss after irradiation, the experimental results gave EBR ranging from 10 to 1.3 for survival rates from 92 to 2% [fr

Neutron activation analysis with pulsed 14 MeV neutrons for the characterization of heterogeneous radioactive wastes; Neutronenaktivierungsanalyse mit gepulsten 14 MeV Neutronen zur Charakterisierung heterogener radioaktiver Abfaelle

Energy Technology Data Exchange (ETDEWEB)

Mildenberger, Frank

2017-07-01

For the transport, interim storage and disposal of radioactive waste, it is assumed to have knowledge of the radioactive and non-radioactive inventory. In order to determine the radioactive inventory destructive (e.g. α-, β-, γ-measurements according to wet chemical sample preparation) and non-destructive (e.g. γ-scanning and neutron measurements) measurement methods are used. For the characterization of non-radioactive substances a prototype for the assay of small-volume (50 L) samples was constructed and parameterized using the neutron activation analysis (NAA) with a pulsed 14 MeV neutron source. Subsequently, the non-destructive analytical method called MEDINA (Multi Element Detection Based on Instrumental Neutron Activation) for 200 l waste drums was developed in a cooperation between RWTH Aachen University and Forschungszentrum Juelich GmbH. The aim of this thesis is to investigate and characterize heterogeneous mixed samples regarding their material composition as well as their inhomogeneous distribution. For this purposes, studies were carried out on 200 l steel drums with heterogeneous matrices using the NAA in the MEDINA facility. The samples are composed out of a mixture of concrete and polyethylene (PE) bodies. Due to its high hydrogen content, the PE can have a strong influence on the neutron moderation and neutron absorption and can thereby occur as a possible disturbance variable in the characterization of the non-radioactive inventory. For these studies a pulsed 14 MeV neutron source is used to record the prompt and delayed γ-rays between the neutron pulses, separately. Thus, the performance of the MEDINA method relating to strongly moderating mixed matrices and their characterization is studied. In order to optimize the measurement of delayed γ-rays without any appreciable interference of prompt γ-rays, the decay of thermal neutrons was studied and the thermal neutron die-away time was determined. It ranges between 2 and 5 ms according to

Calculation of neutron and gamma-ray energy spectra in liquid air and liquid nitrogen due to 14-MeV neutron and californium-252 sources

International Nuclear Information System (INIS)

Straker, E.A.; Gritzner, M.L.; Harris, L. Jr.

1978-01-01

Calculations of neutron and gamma-ray fluences from 14-MeV neutron and 252 Cf sources in liquid air and liquid nitrogen have been performed. These calculations were made specifically for comparison with experimental data measured at Stohl, Federal Republic of Germany. The discrete-ordinates method was utilized with neutron and gamma-ray cross sections from ENDF/B-IV. One-dimensional calculational models were developed for the sources and tank. Limited comparisons are made with experimental data

Cross section of the {sup 11}B(n,p) {sup 11}Be reaction for 14.7-16.9 MeV neutrons

Energy Technology Data Exchange (ETDEWEB)

Stepancinc, B Z; Stanojevic, D M; Popic, V R; Aleksic, M R [Institute of nuclear sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)

1966-07-15

The cross section of the {sup 11}B(n,p){sup 11}Be reaction was determined for neutron energy range from 14.7 to 16.9 MeV using the activation method. Activity measurements were done by using a coincidence spectrometer essentially consisting of two plastic scintillators. Energy dependent cross section values are presented together with the previously measured values for the energy range 14.5 - 16.9 MeV.

Determination of phosphorus and potassium in sugar cane leaves by 14 MeV neutrons

International Nuclear Information System (INIS)

Diaz, R.A.; Nagy, A.Z.; Bakos, L.; Soria, J.C.

1979-04-01

The possibilities of N, P, K evaluation in samples of sugar cane leaves were discussed. A method for determining P and K content in this samples by 14 MeV neutron activation analysis is described. Corrections for K and Si were taken into account. The limit of detection for P was 0.1 mg and for K it was 4 mg. The precision for P and K was 10% in agreement with the values given by other authors. (author)

Absolute determination of copper and silver in ancient coins using 14 MeV neutrons

Science.gov (United States)

Chalouhi, Ch.; Hourani, E.; Loos, R.; Melki, S.

1982-09-01

A method for absolute determination of copper and silver in ancient coins is described. Activation analysis by 14 MeV neutrons is performed. In the experimental procedure emphasis is placed on corrections for neutrons and gamma attenuation. In the analytical procedure, a multi linear-regression calculation is used to separate different contributions to the 511 keV gamma peak. The precision in the absolute determination of Cu and Ag is better than 2% in recent coins of definite shapes, whereas it is a somewhat lower in ancient coins of irregular shapes. The method was applied to ancient coins provided by the Museum of the American University of Beirut. Overall consistency and suitability of the method were obtained.

Absolute determination of copper and silver in ancient coins using 14 MeV neutrons

International Nuclear Information System (INIS)

Chalouhi, C.; Hourani, E.; Loos, R.; Melki, S.

1982-01-01

A method for absolute determination of copper and silver in ancient coins is described. Activation analysis by 14 MeV neutrons is performed. In the experimental procedure emphasis is placed on corrections for neutrons and gamma attenuation. In the analytical procedure, a multi linear-regression calculation is used to separate different contributions to the 511 keV gamma peak. The precision in the absolute determination of Cu and Ag is better than 2% in recent coins of definite shapes, whereas it is a somewhat lower in ancient coins of irregular shapes. The method was applied to ancient coins provided by the Museum of the American University of Beirut. Overall consistency and suitability of the method were obtained. (orig.)

Absolute determination of copper and silver in ancient coins using 14 MeV neutrons

Energy Technology Data Exchange (ETDEWEB)

Chalouhi, C.; Hourani, E.; Loos, R.; Melki, S. (Faculty of Science, Beirut (Lebanon))

1982-09-15

A method for absolute determination of copper and silver in ancient coins is described. Activation analysis by 14 MeV neutrons is performed. In the experimental procedure emphasis is placed on corrections for neutrons and gamma attenuation. In the analytical procedure, a multi linear-regression calculation is used to separate different contributions to the 511 keV gamma peak. The precision in the absolute determination of Cu and Ag is better than 2% in recent coins of definite shapes, whereas it is a somewhat lower in ancient coins of irregular shapes. The method was applied to ancient coins provided by the Museum of the American University of Beirut. Overall consistency and suitability of the method were obtained.

Development of a “Fission-proxy” Method for the Measurement of 14-MeV Neutron Fission Yields at CAMS

Energy Technology Data Exchange (ETDEWEB)

Gharibyan, Narek [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2016-10-25

Relative fission yield measurements were made for 50 fission products from 25.6±0.5 MeV alpha-induced fission of Th-232. Quantitative comparison of these experimentally measured fission yields with the evaluated fission yields from 14-MeV neutron-induced fission of U-235 demonstrates the feasibility of the proposed fission-proxy method. This new technique, based on the Bohr-independence hypothesis, permits the measurement of fission yields from an alternate reaction pathway (Th-232 + 25.6 MeV α → U-236* vs. U-235 + 14-MeV n → U-236*) given that the fission process associated with the same compound nucleus is independent of its formation. Other suitable systems that can potentially be investigated in this manner include (but are not limited to) Pu-239 and U-237.

Progress report on the 14-MeV fission cross section measurements

International Nuclear Information System (INIS)

1979-01-01

The development of a recoil proton monitor was completed. It will be used to measure the neutron flux in the 14-MeV fisson cross section measurements. Extensive calculations of the efficiency of this monitor were made and compared with the calculations of other authors. It is clear that a major source of uncertainty in the efficiency is the lack of precise knowledge of the angular distribution of the n-p elastic scattering cross section. This leads to a change in efficiency of 3% depending on the form of the angular distribution that is used. A 4πβ-γ coincidence system was assembled to investigate the K-correction in determining the absolute activity of foil sources. Iron foils will be used as secondary flux standards in comparing the 14-MeV neutron flux with the fluxes in other laboratories, so this is an important correction to measure. The target and target holders that will be used in the 14-MeV measurements were designed and constructed. Preparations were completed to measure the angular distribution of the fission fragments produced in neutron-induced fission at 14 MeV. 2 figures

Determination of oxide film thickness on aluminium using 14-MeV neutron activation and BET method

International Nuclear Information System (INIS)

Foerster, H.

1983-01-01

A new method is described for the determination of the mean film thickness of aluminium oxides by 14-MeV neutron activation analysis of the oxygen and by BET measurement of the surface area. The mean film thickness obtained is independent of the surface roughness. Stable oxide films consisting of only a few atomic layers of oxygen are detected on aluminium. (author)

Rat mammary-cell survival following irradiation with 14.3-MeV neutrons

International Nuclear Information System (INIS)

Mahler, P.A.; Gould, M.N.; DeLuca, P.M. Jr.; Pearson, D.W.; Clifton, K.H.

1982-01-01

The survival of rat mammary gland cells irradiated in situ with either single or split doses of 14.3-MeV neutrons was determined by an in vivo transplantation assay. The single-dose data are best fit to the multitarget single-hit model by the parameters D 0 = 97 cGy and n = 0.6 while the split-dose data are best fit by the parameters D 0 = 100 cGy and n = 1.2. Analysis of the combined data sets suggests that the two survival curves are not identical. Comparison of these data with previously published results following irradiation with 250-kVp x-rays is reported

Rat mammary cell survival following irradiation with 14.3-MeV neutrons

International Nuclear Information System (INIS)

Mahler, P.A.; Gould, M.N.; DeLuca, P.M. Jr.; Pearson, D.W.; Clifton, K.H.

1982-01-01

The survival of rat mammary gland cells irradiated in situ with either single or split doses of 14.3-MeV neutrons was determined by an in vivo transplantation assay. The single-dose data are best fit to the multitarget single-hit model by the parameters D/sub o/ = 97 cGy and n = 0.6 while the split-dose data are best fit by the parameters D/sub o/ = 100 cGy and n = 1.2.Analysis of the combined data sets suggests that the two survival curves are not identical. Comparison of these data with previously published results following irradiation with 250-kVp X rays is reported

A study of Venus surface elemental composition from 14 MeV neutron induced gamma ray spectroscopy: Activation analysis

International Nuclear Information System (INIS)

Jun, I.; Kim, W.; Smith, M.; Mitrofanov, I.; Litvak, M.

2011-01-01

The surface elemental composition of Venus can be determined using an artificially pulsed 14 MeV neutron generator (PNG) combined with a gamma ray spectrometer (GRS). The 14 MeV neutrons will interact with the surface materials and generate gamma rays, characteristic of specific elements, whose energy spectrum will be measured by GRS. These characteristic gamma rays are produced mainly through 3 different neutron interaction mechanisms: capture, inelastic, and activation reactions. Each reaction type has a different neutron energy dependency and different time scale for gamma ray production and transport. Certain elements are more easily identified through one reaction type over the others. Thus, careful analysis of the gamma ray spectra during and after the neutron pulse provides a comprehensive understanding of the surface elemental composition. In this paper, we use a well-tested neutron/gamma transport code, called Monte Carlo N-Particles (MCNP), to investigate the measurement capability of a PNG-GRS detection system through the neutron activation reactions. An activation analysis was performed for a representative soil composition of Venus with a notional operational scenario of PNG and GRS. The analysis shows that the proposed instrument concept can identify most of the modeled surface elements at Venus with sufficient accuracy through the activation mode. Specifically, U, Th, K, Si can be measured to within 1%, Fe within 2%, Al within 10%, Ca within 5%, Mg with 15%, Mn with 20%, and Cl within 6%. Although modeled in the analysis, it is shown that the activation mode alone cannot distinguish the S and Ti peaks.

The construction of a facility for 14 Mev neutron activation analysis of oxygen in aluminium

International Nuclear Information System (INIS)

Bjoernstad, T.; Alstad, J.

1984-02-01

The article describes the construction and performance of a facility for 14 MeV neutron activation analysis, mainly for oxygen in aluminium, at the University of Oslo. It consists of a sealed tube neutron generator, a biaxial rotation system for samples in irradiation position, a mechanism for automatic separation of sample and container, and appropriate detectors and counting electronics. Especially considered are the procedures for sample preparation and packing, standardization, optimization of the energy range for integration and optimization of the irradiation, decay and counting times. The applicability of the facility is exemplified by analytical results from comparative investigations in different laboratories using different methods. (Auth.)

[International Panel on 14 MeV Intense Neutron Source Based on Accelerators for Fusion Materials Study

International Nuclear Information System (INIS)

Thoms, K.R.; Wiffen, F.W.

1991-01-01

Both travelers were members of a nine-person US delegation that participated in an international workshop on accelerator-based 14 MeV neutron sources for fusion materials research hosted by the University of Tokyo. Presentations made at the workshop reviewed the technology developed by the FMIT Project, advances in accelerator technology, and proposed concepts for neutron sources. One traveler then participated in the initial meeting of the IEA Working Group on High Energy, High Flux Neutron Sources in which efforts were begun to evaluate and compare proposed neutron sources; the Fourth FFTF/MOTA Experimenters' Workshop which covered planning and coordination of the US-Japan collaboration using the FFTF reactor to irradiate fusion reactor materials; and held discussions with several JAERI personnel on the US-Japan collaboration on fusion reactor materials

Evaluation and benchmarking of nuclear data of vanadium in integral experiments with 14-MeV neutrons

CERN Document Server

Blokhin, A I; Chuvilin, D; Livke, A V; Manokhin, V N; Markovskij, D; Nagorny, V; Nefedov, Yu A; Orlov, R; Savin, M; Semenov, V; Shmarov, A; Shvetsov, A M; Zagryadsky, V; Zhitnik, A

2001-01-01

The measurements of the gamma-ray and neutron leakage spectra from three vanadium spheres with diameter 10, 24 and 34 cm at their internal irradiation by 14-MeV neutrons were carried out in frame of the ISTC Project no. 910 in collaboration with FZK. All the spheres have the same geometry of the central hole of 3 cm in diameter. The neutron leakage spectra were measured by a scintillation detector, and by a gas proportional counter. The gamma-ray leakage spectra were measured with help of a crystal NaI(Tl). Analysis of these experiments is performed with the new evaluated nuclear data files prepared in frame of the project activities. A comparison of experimental and calculated neutron and gamma-ray leakage spectra from three vanadium spheres is given.

Simultaneous determination of nitrogen and phosphorus in cereals using 14 MeV Neutron Activation Analysis

International Nuclear Information System (INIS)

Bejarano, R.

1992-01-01

A method using 14 MeV neutron activation analysis was developed form non-destructive simultaneous determination of N and P in cereals. The samples were irradiated 5 min. after 0,5 min. decay time. The induced activities were measured using gamma spectrometry with Nal(Tl) well type detector. The accuracy, precision and detection limits obtained are discussed as well as the analytical results for different types of cereals. (Author) 10 refs., 8 tab., 1 fig

The prediction of Neutron Elastic Scattering from Tritium for E(n) = 6-14 MeV

International Nuclear Information System (INIS)

Anderson, J.D.; Dietrich, F.S.; Luu, T.; McNabb, D.P.; Navratil, P.; Quaglioni, S.

2010-01-01

In a recent report Navratil et al. evaluated the angle-integrated cross section and the angular distribution for 14-MeV n+T elastic scattering by inferring these cross sections from accurately measured p+3He angular distributions. This evaluation used a combination of two theoretical treatments, based on the no-core shell model and resonating-group method (NCSM/RGM) and on the R-matrix formalism, to connect the two charge-symmetric reactions n+T and p+ 3 He. In this report we extend this treatment to cover the neutron incident energy range 6-14 MeV. To do this, we evaluate angle-dependent correction factors for the NCSM/RGM calculations so that they agree with the p+ 3 He data near 6 MeV, and using the results found earlier near 14 MeV we interpolate these correction factors to obtain correction factors throughout the 6-14 MeV energy range. The agreement between the corrected NCSM/RGM and R-Matrix values for the integral elastic cross sections is excellent (±1%), and these are in very good agreement with total cross section experiments. This result can be attributed to the nearly constant correction factors at forward angles, and to the evidently satisfactory physics content of the two calculations. The difference in angular shape, obtained by comparing values of the scattering probability distribution P(μ) vs. μ(the cosine of the c.m. scattering angle), is about ±4% and appears to be related to differences in the two theoretical calculations. Averaging the calculations yields P(μ) values with errors of ±2 1/2 % or less. These averaged values, along with the corresponding quantities for the differential cross sections, will form the basis of a new evaluation of n+T elastic scattering. Computer files of the results discussed in this report will be supplied upon request.

The prediction of Neutron Elastic Scattering from Tritium for E(n) = 6-14 MeV

Energy Technology Data Exchange (ETDEWEB)

Anderson, J D; Dietrich, F S; Luu, T; McNabb, D P; Navratil, P; Quaglioni, S

2010-06-14

In a recent report Navratil et al. evaluated the angle-integrated cross section and the angular distribution for 14-MeV n+T elastic scattering by inferring these cross sections from accurately measured p+3He angular distributions. This evaluation used a combination of two theoretical treatments, based on the no-core shell model and resonating-group method (NCSM/RGM) and on the R-matrix formalism, to connect the two charge-symmetric reactions n+T and p+{sup 3}He. In this report we extend this treatment to cover the neutron incident energy range 6-14 MeV. To do this, we evaluate angle-dependent correction factors for the NCSM/RGM calculations so that they agree with the p+{sup 3}He data near 6 MeV, and using the results found earlier near 14 MeV we interpolate these correction factors to obtain correction factors throughout the 6-14 MeV energy range. The agreement between the corrected NCSM/RGM and R-Matrix values for the integral elastic cross sections is excellent ({+-}1%), and these are in very good agreement with total cross section experiments. This result can be attributed to the nearly constant correction factors at forward angles, and to the evidently satisfactory physics content of the two calculations. The difference in angular shape, obtained by comparing values of the scattering probability distribution P({mu}) vs. {mu}(the cosine of the c.m. scattering angle), is about {+-}4% and appears to be related to differences in the two theoretical calculations. Averaging the calculations yields P({mu}) values with errors of {+-}2 1/2 % or less. These averaged values, along with the corresponding quantities for the differential cross sections, will form the basis of a new evaluation of n+T elastic scattering. Computer files of the results discussed in this report will be supplied upon request.

Determination of Oxygen in Aluminum by Means of 14 MeV Neutrons with an Account of Flux Attenuation in the Sample

Energy Technology Data Exchange (ETDEWEB)

Brune, D; Jirlow, K

1967-11-15

This study concerns the determination of oxygen present at low levels in aluminum using the 14 MeV neutron activation technique. The sensitivity obtained amounted to 0.2 mg oxygen. Various nuclear methods for the oxygen determination have been briefly reviewed. The attenuation of fast neutrons inside the aluminum samples has been calculated.

Determination of oxygen in coals by activation analysis with 14 MeV neutrons

International Nuclear Information System (INIS)

Arbildo, A.; Espinosa, R; Poma, C.; Eyzaguirre, J.; Hinostroza, H.

1989-01-01

A method for non-destructive oxygen determination in coals was developed. It is based on O-16(n,p)N-16 nuclear reaction with 14 MeV neutrons produced in an AID-J 25 neutron generator. This analysis was possible because of the interface development to control the whole irradiation process and subsequent measures of N-16 produced activity from a microcomputer this method was additionally automated by the software development to treat the recorded spectrum in a multiscalimeter analyser. It is described our computer programs and it is shown the results for coal samples from different origins. It is estimated the organic carbon coal in samples from the oxygen analysis. And it is suggested a correlatian between such content and volatile material. Irradiating, decreasing and counting time added up 45 seconds, giving a fast analysis and obtaining accuracy between 1 and 3

Measurements of 14-MeV neutron cross-sections for the production of isomeric states in hafnium isotopes

International Nuclear Information System (INIS)

Patrick, B.H.; Sowerby, M.G.; Wilkins, C.G.; Russen, L.C.

1990-01-01

The cross sections for the production of isomeric states in the reactions 179 Hf(n,2n) 178m2 Hf, 180 Hf(n,2n) 179m2 Hf, 179 Hf(n,n') 179m2 Hf with 14 MeV neutrons have been measured and compared with the theoretical ones. 4 refs, 3 figs, 4 tabs

Study of the flux attenuation and energy degradation of 14.8 MeV neutrons in different materials

International Nuclear Information System (INIS)

Boufraqech, A.

1981-01-01

The attenuation of 14.8 MeV neutrons has been determined using the 63-Cu(n,2n)62-Cu threshold reaction for the detection of the primary neutrons. The attenuation of primary flux in different materials can be well described by a simple exponential relation based on the removal cross section. The microscopic removal cross sections determined for graphite, aluminium, iron and lead are as follows 0.73 +- 0.04, 1.04 +-0.04, 1.41 +- 0.02 and 2.63 +- 0.12 barn respectively. The dependance of secondary neutron spectrum on the thickness of slabs has also been investigated by threshold detectors. 15 refs., 38 figs., 23 tabs. (author)

Measurement of the energy spectrum with proportional counters with spherical cathodes between 20 keV and 2.5 MeV with the propagation of 14 MeV neutrons in liquid nitrogen and liquid air

International Nuclear Information System (INIS)

Schneider-Kuehnle, P.

1974-01-01

This work deals with the measurement of the energy spectrum of a 14 MeV neutron source in liquid nitrogen and liquid air in the energy region of 20 keV to 2.5 MeV as a function of the distance from the source. The measured results together with those of a scintispectrometer which measures the energies between 2.5 MeV and 14 MeV, are to serve as experimentally-supported input data for shielding calculations and are to enable the checking of transport theoretical calculations. (orig./LH) [de

Identification and spectrometry of charged particles produced in reactions induced by 14 MeV neutrons. II

International Nuclear Information System (INIS)

Sellem, C.; Perroud, J.P.; Loude, J.F.

1975-01-01

A counter telescope consisting of gas proportional counters, a thin semiconductor detector and a thick one has been built and used for the study of the angular differential cross sections of (n, charged particles) reactions induced by 14 MeV neutrons. Detection of the α-particles emitted in the neutron production reaction 3 H(d,n) 4 He gives a time reference for the measurement of the time of flight of the charged particles and allows a precise monitoring of the intensity of the neutron beam. High energy protons, deuterons and tritons are identified by their energy losses in the thin semiconductor detector and in the thick one and by their time of flight. Low energy protons, deuterons, tritons and all α-particles stop in the thin semiconductor detector and are identified by their energy losses in this detector and in one gas proportional counter as well as by their time of flight. It is possible to identify and to measure the energy of all charged particles in the energy range of 2 to 15 MeV: a very low background results from the use of the time of flight. (Auth.)

Proliferation kinetics of cultured cells after irradiation with X-rays and 14 MeV neutrons studied by time-lapse cinematography

Energy Technology Data Exchange (ETDEWEB)

Kooi, M.W.; Stap, J.; Barendsen, G.W. (Amsterdam Univ. (Netherlands). Lab. for Radiobiology)

1984-06-01

Exponentially growing cells of an established line derived from a mouse osteosarcoma (MOS) have been studied by time-lapse cinematography after irradiation with 3 Gy of 200 kV X- rays or 1.5 Gy of 14 MeV neutrons. The results show that the radiation doses applied cause an equal elongation of the mean cell cycle time Tsub(c), which is largest in the irradiated cells but persists in the three subsequent generations. After 3 Gy of X-rays, mitotic delay is largest in cells irradiated in later stages of the cycle, but this difference is not observed after 1.5 Gy of 14 MeV neutrons. In subsequent generations the Tsub(c) values show larger variations among descendents of cells treated in the same stage of the cycle as compared to controls but this variation is equal for the doses of X-rays and neutrons applied. Division probability was significantly reduced in irradiated cells as well as in subsequent generations, whereas with neutrons as compared to X-rays the damage is expressed in earlier generations, with less variation as a function of the cell cycle.

Proliferation kinetics of cultured cells after irradiation with X-rays and 14 MeV neutrons studied by time-lapse cinematography

International Nuclear Information System (INIS)

Kooi, M.W.; Stap, J.; Barendsen, G.W.

1984-01-01

Exponentially growing cells of an established line derived from a mouse osteosarcoma (MOS) have been studied by time-lapse cinematography after irradiation with 3 Gy of 200 kV X- rays or 1.5 Gy of 14 MeV neutrons. The results show that the radiation doses applied cause an equal elongation of the mean cell cycle time Tsub(c), which is largest in the irradiated cells but persists in the three subsequent generations. After 3 Gy of X-rays, mitotic delay is largest in cells irradiated in later stages of the cycle, but this difference is not observed after 1.5 Gy of 14 MeV neutrons. In subsequent generations the Tsub(c) values show larger variations among descendents of cells treated in the same stage of the cycle as compared to controls but this variation is equal for the doses of X-rays and neutrons applied. Division probability was significantly reduced in irradiated cells as well as in subsequent generations, whereas with neutrons as compared to X-rays the damage is expressed in earlier generations, with less variation as a function of the cell cycle. (author)

Use of 14 MeV neutrons in analysis of explosive class materials

International Nuclear Information System (INIS)

Dighe, P.M.; Pansare, G.R.; Bhoraskar, V.N.

1992-01-01

Samples of explosive class materials were analised by 14 MeV neutron activation technique to estimate concentrations of oxygen, nitrogen, aluminium and chlorine. For aluminized explosives, test of stability against temperature was carried out by heating samples at 75 deg C and loss of nitrogen was studied by measuring the ratio of aluminium to nitrogen in the sample. Loss of oxygen and nitrogen in a triple base propellant heated at 71.6 deg C, was also estimated by measuring residual oxygen and nitrogen in a heated sample. This technique is convenient to adopt in the laboratory and useful to decide quickly the suitability of explosive class materials for practical applications. (author) 8 refs.; 2 figs.; 1 tab

Multipurpose intense 14 MeV neutron source at Bratislava: Design study

International Nuclear Information System (INIS)

Pivarc, J.; Hlavac, S.; Kral, J.; Oblozinsky, P.; Ribansky, I.; Turzo, I.

1980-05-01

The present state of design of the multipurpose intense 14 MeV neutron source based on a D + ion beam and a metal tritide target is reported. It is essentially a 300 keV electrostatic air insulated accelerator capable to accelerate a deuterium ion beam up to 10 mA. With such a beam and a beam spot of 1 cm 2 , a neutron yield typically 10 12 n/s and a useful target lifetime of around 10 h are expected. Various users requirements are met by means of three beam lines: an intense, low current dc and a low current fast pulsed. The key components of the intense source section are the rotating target and the ion source. The rotating target is proposed, with respect of the heat dissipation and the removal of 3 kW/cm 2 , in continuous operation. A rotation speed up to 1100 rpm is considered. The ion source should deliver about 0.5 kW of extracted D + ion beam power. A duoplasmatron source with an electrostatic beam focusing system has been selected. Low current sections of the neutron source may operate with a high frequency ion source as well. The dc section for maximum yields around 10 10 n/s is designed with special regard to beam monitoring. The fast pulsed section should produce up to 1 ns compressible pulsed D + ion beam on a target spot with 5 MHz repetition rate. The report includes information about other components of the neutron source as a high voltage power supply, a vacuum system, beam transport, a diagnostic and control system and basic information about neutron source cells and radiation protection. (author)

Measurement of neutron captured cross-sections in 1-2 MeV

Energy Technology Data Exchange (ETDEWEB)

Kim, Gi Dong; Kim, Young Sek; Kim, Jun Kon; Yang, Tae Keun [Korea Institutes of Geoscience and Mineral Resources, Taejeon (Korea)

2001-04-01

The measurement of neutron captured reaction cross sections was performed to build the infra system for the production of nuclear data. MeV neutrons were produced with TiT target and {sup 3}T(p,n){sup 3}He reaction. The characteristics of TiT thin film was analyzed with ERD-TOF and RBS. The results was published at Journal of the Korea Physical Society (SCI registration). The energy, the energy spread and the flux of the produced neutron were measured. The neutron excitation functions of {sup 12}C and {sup 16}O were obtained to confirm the neutron energy and neutron energy spread. The neutron energy spread found to be 1.3 % at the neutron energy of 2.077 MeV. The {sup 197}Au(n,{gamma}) reaction was performed to obtain the nerutron flux. The maximum neutron flux found to be 1 x 10{sup 8} neutrons/sec at the neutron energy of 2 MeV. The absolute efficiency of liquid scintillation detector was obtained in the neutron energy of 1 - 2 MeV. The fast neutron total reaction cross sections of Cu, Fe, and Au were measured with sample in-out method. Also the neutron captured reaction cross sections of {sup 63}Cu were measured with fast neutron activation method. The measurement of neutron total reaction cross sections and the neutron captured reaction cross sections with fast neutrons were first tried in Korea. The beam pulsing system was investigated and the code of calculating the deposition spectrums for primary gamma rays was made to have little errors at nuclear data. 25 refs., 28 figs., 14 tabs. (Author)

Comparisons of vector analyzing-power data and calculations for neutron-deuteron elastic scattering from 10 to 14 MeV

International Nuclear Information System (INIS)

Howell, C.R.; Tornow, W.; Murphy, K.; Pfuetzner, H.G.; Roberts, M.L.; Li, A.; Felsher, P.D.; Walter, R.L.; Slaus, I.; Treado, P.A.; Koike, Y.

1987-01-01

High-accuracy analyzing-power A y (θ) data for n-d elastic scattering at 12 MeV have been measured using the polarized-neutron facilities at the Triangle Universities Nuclear Laboratory (TUNL). The present data have been combined with previous n-d measurements at 10, 12, and 14.1 MeV to form the highest-accuracy A y (θ) data set for n-d elastic scattering below 20 MeV. These data are compared to recent Faddeev-based neutron-deuteron (n-d) calculations which use the Paris and Bonn equivalent separable potentials PEST and BEST, as well as Doleschall's representation of the P- and D-wave nucleon-nucleon interactions. None of these models adequately describe the data in the angular region around the maximum of A y (θ). Possible reasons for the discrepancies are discussed. The sensitivity of the present Faddeev-based calculations to various angular momentum components of the nucleon-nucleon interaction are examined. (Auth.)

Measurement and analysis of 14 MeV neutron-induced double-differential neutron emission cross sections needed for fission and fusion reactor technology

International Nuclear Information System (INIS)

Wang Dahai; Mehta, M.K.

1988-07-01

The main objectives of this IAEA Co-ordinated Research Programme are to improve the current status of data for 14 MeV neutron-induced double-differential neutron emission cross sections for V, Cr, Fe, Nb, Ta and 238 U. The principal objectives of this first meeting were to report on the status of participants' work, to exchange experience in experimental work and to establish the future work. Considering the unsatisfactory status of the data for 6 Li, 7 Li, 9 Be, Mo, W and Bi and their importance in fusion reactor technology participants agreed to include these isotopes in the programme

Effects of 14 MeV neutron irradiation on creep of nickel and niobium

International Nuclear Information System (INIS)

Barmore, W.; Ruotola, A.; Raymond, E.; Mukherjee, A.

1983-01-01

Flux, stress and temperature effects on the creep strength of nickel and niobium were observed in situ at the RTNS-II 14 MeV neutron source at Lawrence Livermore National Laboratory. Creep test were done on Ni and Nb near 0.3 Tsub(m) with stresses to 280 MPa in a high vacuum test unit using a digital computer for control and data acquisition. Cyclic flux tests produced dramatic changes in creep rate. This creep behavior is attributed to the point defect fluctuations in the crystal structure. Analysis of creep and stress relaxation under steady state flux indicates that an intermediate temperature, thermally activated deformation mechanism is rate controlling. (orig.)

14MeV facility and research in IPPE

Energy Technology Data Exchange (ETDEWEB)

Simakov, S P; Androsenko, A A; Androsenko, P A; Devkin, B V; Kobozev, M G; Lychagin, A A; Sinitca, V V; Talalaev, V A [Institute of Physics and Power Engineering, Obninsk (Russian Federation); Chuvilin, D Yu; Borisov, A A; Zagryadsky, V A [Institute of Atomic Energy, Moscow (Russian Federation)

1993-07-01

Review of experimental facility and research, performed at 14MeV incident neutron energy in the Institute of Physics and Power Engineering, are given. These studies cover the next topics: double differential neutron emission cross sections (DDX), neutron-gamma coincidence experiments (n, n'{gamma}) and neutron leakage spectra for spherical assemblies (benchmark). The paper contains description and main parameters of pulsed neutron generator KG-0.3, fast neutron time of flight spectrometer, measuring and data reduction procedures, review of experimental data. Results of experiments are compared with other data; evaluated data files BROND-2, ENDF/B6, JENDL-3; basic theoretical and transport model calculations. (author)

14MeV facility and research in IPPE

International Nuclear Information System (INIS)

Simakov, S.P.; Androsenko, A.A.; Androsenko, P.A.; Devkin, B.V.; Kobozev, M.G.; Lychagin, A.A.; Sinitca, V.V.; Talalaev, V.A.; Chuvilin, D.Yu.; Borisov, A.A.; Zagryadsky, V.A.

1993-07-01

Review of experimental facility and research, performed at 14MeV incident neutron energy in the Institute of Physics and Power Engineering, are given. These studies cover the next topics: double differential neutron emission cross sections (DDX), neutron-gamma coincidence experiments (n, n'γ) and neutron leakage spectra for spherical assemblies (benchmark). The paper contains description and main parameters of pulsed neutron generator KG-0.3, fast neutron time of flight spectrometer, measuring and data reduction procedures, review of experimental data. Results of experiments are compared with other data; evaluated data files BROND-2, ENDF/B6, JENDL-3; basic theoretical and transport model calculations. (author)

Mammary carcinogenesis induced by three consecutive 14 MeV neutron irradiations in Sprague-Dawley rats

International Nuclear Information System (INIS)

Jacrot, M.; Mouriquand, J.; Mouriquand, C.

1978-01-01

At high doses (400 to 800 rads) the relative biological effectiveness (R.B.E.) of neutrons is two or three times greater than that of X-rays or gamma radiation. The neutron irradiation-induced mammary carcinogenesis threshold, if any, is certainly very low in Sprague-Dawley females. The purpose of this work is to test the possibilities offered by three consecutive 14 MeV neutron irradiations in the mammary carcinogenesis region of Sprague-Dawley rats. The results of these experiments show a hormone-dependence of tumour promotion similar to that observed with chemical carcinogenetic agents. However these tumours, by their recurrences and possible metastases, bear some resemblance to breast cancers in women. Although the tumour induction frequencies seem modest in relation to those obtained with the DMBA model they should nevertheless prove very useful in the study of hormone effects liable to control the appearance of such radioinduced cancers [fr

Elastic neutron scattering studies at 96 MeV for transmutation.

Science.gov (United States)

Osterlund, M; Blomgren, J; Hayashi, M; Mermod, P; Nilsson, L; Pomp, S; Ohrn, A; Prokofiev, A V; Tippawan, U

2007-01-01

Elastic neutron scattering from (12)C, (14)N, (16)O, (28)Si, (40)Ca, (56)Fe, (89)Y and (208)Pb has been studied at 96 MeV in the10-70 degrees interval, using the SCANDAL (SCAttered Nucleon Detection AssembLy) facility. The results for (12)C and (208)Pb have recently been published, while the data on the other nuclei are under analysis. The achieved energy resolution, 3.7 MeV, is about an order of magnitude better than for any previous experiment above 65 MeV incident energy. A novel method for normalisation of the absolute scale of the cross section has been used. The estimated normalisation uncertainty, 3%, is unprecedented for a neutron-induced differential cross section measurement on a nuclear target. Elastic neutron scattering is of utmost importance for a vast number of applications. Besides its fundamental importance as a laboratory for tests of isospin dependence in the nucleon-nucleon, and nucleon-nucleus, interaction, knowledge of the optical potentials derived from elastic scattering come into play in virtually every application where a detailed understanding of nuclear processes is important. Applications for these measurements are dose effects due to fast neutrons, including fast neutron therapy, as well as nuclear waste incineration and single event upsets in electronics. The results at light nuclei of medical relevance ((12)C, (14)N and (16)O) are presented separately. In the present contribution, results on the heavier nuclei are presented, among which several are of relevance to shielding of fast neutrons.

Measurement of (n,α) cross-sections for Cr, Fe and Ni at 14 MeV neutron energy

International Nuclear Information System (INIS)

Wattecamps, E.; Liskien, H.; Arnotte, F.

1983-01-01

Helium production cross-sections for the main constituents of stainless steel (Cr, Fe, Ni) have recently been published for neutron energies between 5 and 10 MeV. The α-particles were detected with a multi-angle telescope and cross-section data relative to the well known n-p scattering cross-section were deduced. Those measurements have been performed now also at 14 MeV. At this energy the background condition had to be improved by changing the neutron collimation, by reducing the sensitive volume of the ΔE-proportional counters, and by replacing remaining low-Z material inside the chamber by tantalum. Listing mode data acquisition is used and α-particle identification is performed by transforming the observed (ΔE,E) signal into a (MZ 2 ,E) signal. The measurements yield the angle-differential cross sections for five fixed angles. Angle-integrated cross-sections are compared with the few results available in literature. (Auth.)

Investigation of (n, 2n) reaction and fission rates in iron-shielded uranium samples bombarded by 14.9 MeV neutrons

International Nuclear Information System (INIS)

Shani, G.

1976-01-01

The effect of the thickness of iron shielding on the (n, 2n) reaction rate in a fusion reactor (hybrid) blanket is investigated. The results are compared with the fission rate-dependence. Samples of natural uranium are irradiated with 14 MeV neutrons, with iron slabs of various thickness between the neutron generator target and the samples. Both reactions are threshold reactions but the fact that the 238 U (n, 2n) reaction threshold is at 6 MeV and that of fission is at 2 MeV makes the ratio between the two very much geometry-dependent. Two geometrical effects take place, the 1/r 2 and the build-up. While the build-up affects the (n, 2n) reaction rate, the fission rate is affected more by the 1/r 2 effect. The reason is that both elastic and inelastic scattering end up with neutrons with energy above fission threshold, while only elastic scattering brings high energy neutrons to the sample and causes (n, 2n) reaction. A comparison is made with calculated results where the geometrical effects do not exist. (author)

V79 survival following simultaneous or sequential irradiation by 14.8-MeV neutrons and 60Co photons

International Nuclear Information System (INIS)

Higgins, P.D.; DeLuca, P.M. Jr.; Pearson, D.W.; Gould, M.N.

1981-01-01

A unique tandem source irradiation facility, comprised of an intense d-T neutron source and a 60 Co teletherapy unit, has been used to investigate biological response for different neutron/photon configurations. V79 Chinese hamster cells, attached as monolayers in log phase growth, were irradiated at 37 0 C by either 14.8 MeV neutrons, 60 Co or by a mixture of 40% neutrons - 60% photons in simultaneous or sequential application. Measurements of cell survival indicate an increased effectiveness in cell killing for simultaneously administered neutrons and photons than was measured or predicted for sequentially applied beam modalities. An understanding of the magnitude of these interactive effects is important both for calculating accurate effective doses for neutron radiotherapy of deep-seated tumors, for which the photon component is appreciable and for determination of environmental hazards to people occupationally exposed to low levels of photons and neutrons

Neutron-capture cross-section measurements of Xe136 between 0.4 and 14.8 MeV

Science.gov (United States)

Bhike, Megha; Tornow, W.

2014-03-01

Fast-neutron-capture cross-section data on Xe136 have been measured with the activation method between 0.4 and 14.8 MeV. The cross section was found to be of the order of 1 mb at the eleven energies investigated. This result is important to interpret potential neutron-induced backgrounds in the enriched xenon observatory and KamLAND-Zen neutrinoless double-β decay searches that use xenon as both source and detector. A high-pressure sphere filled with Xe136 was irradiated with monoenergetic neutrons produced by the reactions 3H(p ,n)3He, 2H(d ,n)3He, and 3H(d ,n)4He. Indium and gold monitor foils were irradiated simultaneously with the Xe136 to determine the incident neutron flux. The activities of the reaction products were measured with high-resolution γ-ray spectroscopy. The present results are compared to predictions from ENDF/B-VII.1 and TENDL-2012.

Fission Product Yields for 14 MeV Neutrons on 235U, 238U and 239Pu

International Nuclear Information System (INIS)

Mac Innes, M.; Chadwick, M.B.; Kawano, T.

2011-01-01

We report cumulative fission product yields (FPY) measured at Los Alamos for 14 MeV neutrons on 235 U, 238 U and 239 Pu. The results are from historical measurements made in the 1950s–1970s, not previously available in the peer reviewed literature, although an early version of the data was reported in the Ford and Norris review. The results are compared with other measurements and with the ENDF/B-VI England and Rider evaluation. Compared to the Laurec (CEA) data and to ENDF/B-VI evaluation, good agreement is seen for 235 U and 238 U, but our FPYs are generally higher for 239 Pu. The reason for the higher plutonium FPYs compared to earlier Los Alamos assessments reported by Ford and Norris is that we update the measured values to use modern nuclear data, and in particular the 14 MeV 239 Pu fission cross section is now known to be 15–20% lower than the value assumed in the 1950s, and therefore our assessed number of fissions in the plutonium sample is correspondingly lower. Our results are in excellent agreement with absolute FPY measurements by Nethaway (1971), although Nethaway later renormalized his data down by 9% having hypothesized that he had a normalization error. The new ENDF/B-VII.1 14 MeV FPY evaluation is in good agreement with our data.

Cross-sections for the formation of isomeric pair {sup 75}Ge{sup m,g} through (n, 2n), (n, p) and (n, {alpha}) reactions measured over 13.73 MeV to 14.77 MeV and calculated from near threshold to 20 MeV neutron energies

Energy Technology Data Exchange (ETDEWEB)

Attar, F.M.D.; Dhole, S.D. [Department of Physics, University of Pune, Pune-411007 (India); Kailas, S. [Nuclear Physics Division, BARC, Mumbai-400085 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune-411007 (India)], E-mail: vnb@physics.unipune.ernet.in

2009-09-15

The cross-sections for formation of isomeric pair, {sup 75}Ge{sup m}({sigma}{sub m}) and {sup 75}Ge{sup g}({sigma}{sub g}), through {sup 76}Ge(n, 2n), {sup 75}As(n, p) and {sup 78}Se(n, {alpha}) reactions were measured at 13.73 MeV, 14.42 MeV and 14.77 MeV neutrons and also estimated using EMPIRE-II and TALYS codes over neutron energies from near threshold to 20 MeV. For each (n, 2n), (n, p) and (n, {alpha}) reaction, the cross-section initially increases with neutron energy, but starts decreasing as the neutron energy exceeds the respective threshold of (n, 3n), (n, pn) and (n, {alpha}n) reactions. The higher values of {sigma}{sub m} relative to {sigma}{sub g} reveal that the transitions of the excited {sup 75}Ge from higher energy levels to metastable state (7{sup +}/2) are favored as compared to unstable ground state (1{sup -}/2). The present values of cross sections for formation of {sup 75}Ge{sup m,g} through (n, 2n) and (n, {alpha}) reactions are lower, and that of (n, p) reaction are higher compared to most of the corresponding literature cross-sections.

Integral benchmark for the attenuation of 14 MeV neutrons passing through lead layers

International Nuclear Information System (INIS)

Antonov, S.; Vojkov, G.; Ilieva, K.; Jordanova, J.

1987-01-01

The attenuation has been studied of the total 14 MeV neutron flux passing through an iron collimator and directly located behind lead slabs with thicknesses 2.5, 5.0, 7.5, 10.0 and 12.5 cm. A comparison is made between the calculated data and results from a benchmark experiment. The experiment is analysed with an one-dimensional model based on ANISN-code and a tree-dimentional model based on MORSE-code (Monte Carlo method). The energy dependences of the cross-sections and neutron fluxes are represented by a 25-group approximation based on the SUPERTOG program and the files ENDL and ENDF/B-4. The mean deviation of MORSE calculated data from experimental ones is 6.4% for ENDL-data and 8.5% for EDDF-data. ANISN-calculated data show practically full coincidence with experimental ones both for ENDL and ENDF

Proliferation kinetics of cultured cells after irradiation with X-rays and 14 MeV neutrons studied by time-lapse cinematography.

Science.gov (United States)

Kooi, M W; Stap, J; Barendsen, G W

1984-06-01

Exponentially growing cells of an established line derived from a mouse osteosarcoma (MOS) have been studied by time-lapse cinematography after irradiation with 3 Gy of 200 kV X-rays or 1.5 Gy of 14 MeV neutrons. Cell cycle times (Tc) of individual cells and their progeny in three subsequent generations as well as the occurrence of aberrant mitosis have been determined to evaluate the variation in expression of damage in relation to the stage in the intermitotic cycle and the radiation quality. The results show that the radiation doses applied cause an equal elongation of the mean Tc, which is largest in the irradiated cells but persists in the three subsequent generations. After 3 Gy of X-rays, mitotic delay is largest in cells irradiated in later stages of the cycle, but this difference is not observed after 1.5 Gy of 14 MeV neutrons. In subsequent generations the Tc values show larger variations among descendents of cells treated in the same stage of the cycle as compared to controls but this variation is equal for the doses of X-rays and neutrons applied. Division probability was significantly reduced in irradiated cells as well as in subsequent generations, whereby with neutrons as compared to X-rays the damage is expressed in earlier generations, with less variation as a function of the cell cycle.

Response of a carbon-walled proportional counter to 14 MeV neutrons

International Nuclear Information System (INIS)

Lewis, K.D.

1982-01-01

The response of a carbon-walled spherical proportional counter filled with a methane-based tissue-equivalent gas mixture at low pressure and irradiated with 14 MeV neutrons is first measured experimentally and is then calculated theoretically by using an analytical model. The model, called the CISS model, is derived from a consideration of four basic modes of interaction of charged particles generated in neutron-nucleus reactions with the spherical cavity of the detector. Since several quantities which have application in neutron dosimetry, radiation protection, and radiation biology make direct use of such spectra, it is desirable to have the ability to theoretically predict what is expected experimentally. Thus, a comparison between the two response curves is made. The discrepancy between them is investigated by considering several physical phenomena occurring within the detector wall which tend to distort the experimental response curve. In particular, the C(n,n',3α) reaction occurring in the detector wall gives rise to multiple events, originating from a single neutron interaction in the wall simultaneously strike the detector cavity, and are recorded as a single larger event in an experimental spectra. In the analytic model, the simultaneous entry of two charged particles into the cavity is scored as two separate smaller events, uncorrelated in their production. In this work, an effort is made to modify the analytic model prediction of the response curve by correcting for the multiple events which occur. Finally, the CISS model is used to compute mass stopping power corrections for this inhomogeneous detector

Extension of the calibration of an NE-213 liquid scintillator based pulse height response spectrometer up to 18 MeV neutron energy and leakage spectrum measurements on bismuth at 8 MeV and 18 MeV neutron energies

International Nuclear Information System (INIS)

Fenyvesi, A.; Valastyan, I.; Olah, L.; Csikai, J.; Plompen, A.; Jaime, R.; Loevestam, G.; Semkova, V.

2011-01-01

Monoenergetic neutrons were produced at the Van de Graaff accelerator of the EC-JRC-Institute for Reference Materials and Measurements (IRMM, Geel, Belgium). An air-jet cooled D_2-gas target (1.2 bar, ΔE_d = 448 keV) was bombarded with E_d =4976 keV deuterons to produce neutrons up to E_n = 8 MeV energy via the D(d,n)"3He reaction. Higher energy neutrons up to E_n = 18 MeV were produced via the T(d,n)"4He reaction by bombarding a TiT target with E_d =1968 keV deuterons. Pulse height spectra were measured at different neutron energies from E_n = 8 MeV up to E_n = 18 MeV with the NE-213 liquid scintillator based Pulse Height Response Spectrometer (PHRS) of UD-IEP. The energy calibration of the PHRS system has been extended up to E_n = 18 MeV. Pulse height spectra induced by gamma photons have been simulated by the GRESP7 code. Neutron induced pulse height spectra have been simulated by the NRESP7 and MCNP-POLIMI codes. Comparison of the results of measurements and simulations enables the improvement of the parameter set of the function used by us to describe the light output dependence of the resolution of the PHRS system at light outputs of L > 2 light units. Also, it has been shown that the derivation method for unfolding neutron spectra from measured pulse height spectra performs well when relative measurements are done up to E_n = 18 MeV neutron energy. For matrix unfolding purposes, the NRESP7 code has to be preferred to calculate the pulse height response matrix of the PHRS system. Leakage spectra of neutrons behind bismuth slabs of different thicknesses have been measured with the PHRS system by using monoenergetic neutrons. The maximum slab thickness was d = 14 cm. Simulations of the measurements have been carried out with the MCNP-4c code. The necessary nuclear cross-sections were taken from the from the ENDF/B-VII and JEFF.3.1 data libraries. For both libraries, the agreement of measured and simulated neutron spectra is good for the 5 MeV ≤ En ≤ 18 MeV

Measurement of fission cross section for {sup 232}Th(n,f){sup 131}{sub Z}X (Z = 50, 51, 52, 53) reaction induced by neutrons around 14 MeV

Energy Technology Data Exchange (ETDEWEB)

Lan, Chang-lin; Qiu, Yi-jia; Wang, Qiang; Zhang, Zheng-wei; Zhang, Qian; Tan, Jun-cai; Fang, Kai-hong [Lanzhou University, School of Nuclear Science and Technology, Lanzhou (China); Lai, Cai-feng [China Academy of Engineering Physics, Institute of Nuclear Physics and Chemistry, Mianyang (China)

2017-06-15

The fission cross sections of {sup 232}Th(n,f){sup 131m,g}Sn, {sup 232}Th(n,f){sup 131}Sb, {sup 232}Th(n,f){sup 131m,g}Te, {sup 232}Th(n,f){sup 131}I fission reactions induced by 14 MeV neutrons were measured precisely with the neutron activation technique. The neutron flux was monitored by accompanying α particle in the irradiation and the neutron energies were determined by the cross section ratio of {sup 90}Zr(n,2n){sup 89}Zr to {sup 93}Nb(n,2n){sup 92m}Nb reaction. The values of the cross sections of {sup 232}Th(n,f){sup 131m,g}Sn were analyzed, and the cross sections of {sup 232}Th(n,f){sup 131}Sb were deduced to be 6.5±0.7, 6.3±0.6, 6.1±0.6 mb at 14.1±0.3, 14.5±0.3 and 14.8±0.3 MeV, respectively. The values of the cross sections of {sup 232}Th(n,f){sup 131g}Te were deduced to be 1.8 ± 0.1, 1.5 ± 0.1 and 1.4±0.1 mb at 14.1±0.3, 14.5±0.3 and 14.8±0.3 MeV, respectively. The values of the cross sections of {sup 232}Th(n,f){sup 131}I were given as 1.8±0.2, 1.6±0.2, 1.5±0.1 mb at 14.1±0.3, 14.5±0.3 and 14.8±0.3 MeV, respectively. (orig.)

Measurement of formation cross sections producing short-lived nuclei by 14 MeV neutrons. Pr, Ba, Ce, Sm, W, Sn, Hf

International Nuclear Information System (INIS)

Murahira, S.; Satoh, Y.; Honda, N.; Shibata, M.; Yamamoto, H.; Kawade, K.; Takahashi, A.; Iida, T.

1996-01-01

Thirteen neutron activation cross sections for (n,2n), (n,p), (n,np) and (n,α) reactions producing short-lived nuclei with half-lives between 56 s and 24 min were measured in the energy range from 13.4 MeV to 14.9 MeV for Pr, Ba, Ce, Sm, W, Sn and Hf. The cross sections of 179 Hf(n,np) 178m Lu and 180 Hf(n,p) 180 Lu were measured for the first time. (author)

Blank evaluation in nitrogen determination in seed grains by 14 MeV neutron activation analysis

International Nuclear Information System (INIS)

Wasek, M.; Sterlinski, S.

1987-01-01

In this work the term 'blank' signifies total radiation of the sample analyzed except that the element to be determined (analyte) is absent. On the basis of the evaluation of the blank components (nuclear and spectral interferences, air-nitrogen between grains, etc.), a semiempirical formula for calculating the nitrogen content in plant grain samples is proposed. The reliability of the results obtained with the use of this formula was demonstrated for five sorts of seeds (rye, wheat, barley, broad bean and soybean) which were analyzed by the Kjeldahl method and 14 MeV neutron activation analysis, respectively. (author)

99mTc by 99Mo produced at the ENEA-FNG facility of 14MeV neutrons.

Science.gov (United States)

Capogni, M; Pietropaolo, A; Quintieri, L; Fazio, A; De Felice, P; Pillon, M; Pizzuto, A

2018-04-01

A severe supply crisis of 99 Mo, precursor of 99m Tc a diagnostic radionuclide largely used in Nuclear Medicine, occurred in 2008-2009 due to repeated shut-down of the two main (aged) fission reactors. An alternative route for producing 99 Mo by 100 Mo(n,2n) 99 Mo reaction was investigated at ENEA. The experiment, designed according to Monte Carlo simulations performed with the Fluka code, produced 99 Mo by irradiating a natural Molybdenum powdered target with 14MeV neutrons produced at the Frascati Neutron Generator. The 99 Mo specific activity was measured at metrological level by γ-ray spectrometry. Copyright © 2017 Elsevier Ltd. All rights reserved.

NEUTRON-PROTON ANALYZING POWER DATA AT 7.6, 12.0, 14.1, 16.0, 18.5 MeV

OpenAIRE

Weisel , G.; Tornow , W.; Howell , C.; Felsher , P.; Alohali , M.; Chen , Z.; Walter , R.; Lambert , J.; Treado , P.

1990-01-01

Neutron-Proton Ay(θ) measurements have been made at 7.6, 12.0, 14.1, 16.0, and 18.5 MeV. A sensitivity study establishes the importance of Ay(θ) in determining the 3P0, 1, 2 phase shifts in n-p scattering. The data are compared to the predictions of two phase-shift studies (one of which incorporates CIB effects), and the Paris and Bonn NN potenials.

Prediction of (n, 3He) cross sections around 14 MeV

International Nuclear Information System (INIS)

Atasoy, H.; Doekmen, S.

1995-01-01

A comprehensive review of the neutron-induced cross-reactions for (n, 3 He) reactions has been made for the interval of 14 ≤ Z ≤ 84 around 14 MeV neutron energy. For practical purposes, an empirical expression has been found by using the experimental (n, 3 He) cross section values as a function of (N - Z) and (E n - E th ) where (N - Z) is the neutron excess of the target nucleus, E n and E th are the incident neutron energy and the (n, 3 He) threshold energy, respectively. The derived empirical relation gives a good fit with the experimental values

Testing a newly developed single-sphere neutron spectrometer in reference monochromatic fields from 147 keV to 14.8 MeV

Energy Technology Data Exchange (ETDEWEB)

Bedogni, R., E-mail: roberto.bedogni@lnf.infn.it [INFN—LNF Laboratori Nazionali di Frascati, Via E. Fermi n. 40, 00044 Frascati (Italy); Gómez-Ros, J.M. [INFN—LNF Laboratori Nazionali di Frascati, Via E. Fermi n. 40, 00044 Frascati (Italy); CIEMAT, Av. Complutense 40, 28040 Madrid (Spain); Pola, A.; Introini, M.V. [Politecnico di Milano - Dipartimento di Energia, Via Ponzio 34/3, 20133 Milano (Italy); Bortot, D. [INFN—LNF Laboratori Nazionali di Frascati, Via E. Fermi n. 40, 00044 Frascati (Italy); Politecnico di Milano - Dipartimento di Energia, Via Ponzio 34/3, 20133 Milano (Italy); Gentile, A.; Esposito, A.; Mazzitelli, G.; Buonomo, B.; Quintieri, L.; Foggetta, L. [INFN—LNF Laboratori Nazionali di Frascati, Via E. Fermi n. 40, 00044 Frascati (Italy)

2013-06-21

A new neutron spectrometer, designed to simultaneously respond from the thermal domain up to hundreds of MeV neutrons, was designed and built in the framework of the INFN project NESCOFI@BTF. It has been called SP{sup 2} (SPherical SPectrometer) and it consists of 31 thermal neutron detectors embedded in a 25 cm diameter polyethylene sphere with an internal 1 cm thick lead shell. The new spectrometer shows similar performance as the Bonner sphere spectrometer, but has the notable advantage of requiring only one exposure to determine the whole spectrum. The SP{sup 2} response matrix, previously calculated with MCNP, has been experimentally evaluated with monochromatic reference neutron fields from 147 keV to 14.8 MeV at PTB Braunschweig. As suitable thermal neutron detectors, Dysprosium activation foils were adopted at this stage. The results of the experiment confirmed the correctness of the response matrix within an overall uncertainty of ±3%. The next phase of the NESCOFI@BTF project will be the replacement of passive detectors with active counters, thus leading to a real-time spectrometric monitor that is expected to significantly innovate the neutron control task in neutron-producing facilities, such as the beam-lines for industrial irradiation or condensed matter studies.

Emission of γ rays from various materials pulsed with 14-MeV neutrons

International Nuclear Information System (INIS)

Goldberg, E.; Hansen, L.F.; Howerton, R.J.; Komoto, T.T.; Pohl, B.A.

1987-10-01

We have performed a number of experiments at LLNL recently to investigate the leakage of gamma rays from spheres of selected materials pulsed centrally with 14-MeV neutrons. Such spectral information may be carefully compared to calculational results to validate the transport models, particularly the nuclear cross section data base. In the present case, the TART code and SANDYL codes are used to explicitly calculate the observable, the recoil electron spectrum. The materials studied were H 2 O, 6 LiD, Be, C, 14 N, CF 2 , Al, Si, Ti, Fe, Cu, Ta, W, Au, Pb, Th, and 238 U. Generally, agreement was good between experiment and calculation. However, for some, the calculations significantly underestimated or overestimated experiment. For oxygen (i.e., H 2 O), the ENDL cross section set led to a sizeable calculational overestimate. Re-examination led to a large improvement. For tungsten, the calculated output was ∼30% below experiment. A re-evaluation led to closer agreement. 16 refs., 10 figs., 1 tab

Experimental study on 14 MeV neutron irradiation effects in FLASH ROM28F256 and 29C256

International Nuclear Information System (INIS)

He Chaohui; Chen Xiaohua; Li Guozheng; Wang Yanping; Ji Lin; Geng Bin; Yang Hailiang; Liu Enke

2000-01-01

Experimental results of neutron irradiation effects are given for FLASH ROM. New phenomena are observed. The 14 MeV neutron irradiation effects in 28F256 and 29C256 devices are different from the single event effects. Errors are only '0'→'1'. There is a neutron flux threshold. Errors occur when neutron flux is above the threshold, no error occurs when below the threshold. The errors go up with the increase of the neutron flux until all '0' change to '1'. Hard errors, that new data cannot be written in memory with programmer, occur in devices which are measured during irradiation and irradiated in power on mode. Errors rise with the increase of reading times. Under same neutron flux, there is no error in devices in power off mode, however, errors occur in all devices in power on mode, moreover, undefined errors occur

Determination of average fission fraction produced by 14 MeV neutrons in assemblies with large volume of depleted uranium

International Nuclear Information System (INIS)

Wang Dalun; Li Benci; Wang Xiuchun; Li Yijun; Zhang Shaohua; He Yongwu

1991-07-01

The average fission fraction of 238 U caused by 14 MeV neutrons in assemblies with large volume depleted uranium has been determined. The measured value of p f 238U (R ∞ depleted ) 14 was 0.897 ± 0.036. Measurements were also completed for neutron flux distribution and average fission fraction of 235 U isotope in depleted uranium sphere. Values of p f 238U (R depleted ) have been obtained by using a series of uranium spheres. For a sphere with Φ 600 the p f 23 '8 U (R 300 depleted ) is 0.823 ± 0.041, the density of depleted uranium assembly is 18.8g/cm 3 and total weight of assembly is about 2.8t

Increase of the electrical resistance of thin copper film due to 14 MeV neutron irradiation

International Nuclear Information System (INIS)

Agrawal, S.K.; Kumar, U.; Nigam, A.K.; Singh, S.P.

1981-01-01

The variation in the electrical resistance of thin copper film (500 A 0 thick), grown on the glass slide has been measured with increasing 14 MeV neutron irradiation time. The electrical resistance vs irradiation time curve shows an interesting behaviour after an irradiation of 40 minutes. However, there is a net increase in the electrical resistance with increasing neutron dose. The maximum increase in the observed electrical resistance after an irradiation of 115 mins, is 4.45%. The microstructural studies of irradiated film were made using TEM and TED techniques. The TEM patterns up to an irradiation time of 1.00 hr do not show any appreciable change in the microstructure. The TED patterns also do not show any appreciable change in the diffraction pattern up to an irradiation time of 1.0 hr. But after an irradiation time of 1.5 hrs, two extra rings appear in the TED pattern which disappear with increasing neutron irradiation time

Critical study of some soft-tissue equivalent material. Sensitivity to neutrons of 1 keV to 14 MeV

International Nuclear Information System (INIS)

Kerviler, H. de; Pages, L.; Tardy-Joubert, Ph.

1965-01-01

Authors have studied the elastic and inelastic reactions on various elements contribution to kerma in standard soft tissue and as a function of neutron energy from 1 keV to 14 MeV the ratio of kerma in tissue equivalent material to kerma in soft tissue. The results of calculations are made for materials without hydrogen in view to state exactly their neutron sensitivity and for the following hydrogenous materials: Rossi and Failla plastic, MixD, pure polyethylene and a new CEA tissue equivalent (a magnesium fluoride and polyethylene compound). Results for γ-rays are given. (authors) [fr

Neutron-proton analyzing power data at 7.6, 12.0, 14.1, 16.0, 18.5 MeV

International Nuclear Information System (INIS)

Weisel, G.J.; Tornow, W.; Howell, C.R.; Felsher, P.D.; Alohali, M.; Chen, Z.P.; Walter, R.L.; Lambert, J.M.; Treado, P.A.

1990-01-01

Neutron-Proton A y (θ) measurements have been made at 7.6, 12.0, 14.1, 16.0, and 18.5 MeV. A sensitivity study establishes the importance of A y (θ) in determining the 3 P 0,1,2 phase shifts in n-p scattering. The data are compared to the predictions of two phase-shift studies (one of which incorporates CIB effects), and the Paris and Bonn NN potentials

Measurement and theoretical analysis of neutron-induced neutron-emission reactions of 6Li at 10 to 20 MeV region

International Nuclear Information System (INIS)

Ibaraki, Masanobu; Baba, Mamoru; Matsuyama, Shigeo

1998-06-01

We have measured the neutron elastic and inelastic scattering double-differential cross sections of 6 Li at incident neutron energies of 11.5, 14.1 and 18.0 MeV. Based on this data, together with information from other works, a phenomenological neutron optical model potential (OMP) of 6 Li was constructed to describe the total and elastic scattering cross sections from 5 MeV to several tens MeV. This potential also describes well the inelastic scattering to the 1st excited state (E x = 2.186 MeV) via the DWBA calculation with the macroscopic vibrational model. The continuum neutron energy spectra and angular distributions were then analyzed by the theory of final-state interaction extended to the DWBA form, with the assumption that the d-α interaction is dominant in the 3-body final state consisting of n, d and α particles. Such a calculation was found to be successful in explaining the major part of the low-excitation neutron spectra and angular distribution down to the Q-value region of -9 MeV, except for the Q-value range where the n-α quasi-free scattering will give a non-negligible contribution at forward angles. (author). 60 refs

Fission Product Yields of 233U, 235U, 238U and 239Pu in Fields of Thermal Neutrons, Fission Neutrons and 14.7-MeV Neutrons

Science.gov (United States)

Laurec, J.; Adam, A.; de Bruyne, T.; Bauge, E.; Granier, T.; Aupiais, J.; Bersillon, O.; Le Petit, G.; Authier, N.; Casoli, P.

2010-12-01

The yields of more than fifteen fission products have been carefully measured using radiochemical techniques, for 235U(n,f), 239Pu(n,f) in a thermal spectrum, for 233U(n,f), 235U(n,f), and 239Pu(n,f) reactions in a fission neutron spectrum, and for 233U(n,f), 235U(n,f), 238U(n,f), and 239Pu(n,f) for 14.7 MeV monoenergetic neutrons. Irradiations were performed at the EL3 reactor, at the Caliban and Prospero critical assemblies, and at the Lancelot electrostatic accelerator in CEA-Valduc. Fissions were counted in thin deposits using fission ionization chambers. The number of fission products of each species were measured by gamma spectrometry of co-located thick deposits.

Neutron Energy Spectra from Neutron Induced Fission of 235U at 0.95 MeV and of 238U at 1.35 and 2.02 MeV

Energy Technology Data Exchange (ETDEWEB)

Almen, E; Holmqvist, B; Wiedling, T

1971-09-15

The shapes of fission neutron spectra are of interest for power reactor calculations. Recently it has been suggested that the neutron induced fission spectrum of 235U may be harder than was earlier assumed. For this reason measurements of the neutron spectra of some fissile isotopes are in progress at our laboratory. This report will present results from studies of the energy spectra of the neutrons emitted in the neutron induced fission of 235U and 238U. The measurements were performed at an incident neutron energy of 0.95 MeV for 235U and at energies of 1.35 and 2.02 MeV for 238U using time-of-flight techniques. The time-of-flight spectra were only analysed at energies higher than those of the incident neutrons and up to about 10 MeV. Corrections for neutron attenuation in the uranium samples were calculated using a Monte Carlo program. The corrected fission neutron spectra were fitted to Maxwellian temperature distributions. For 235U a temperature of 1.27 +- 0.01 MeV gives the best fit to the experimental data and for 238U the corresponding values are 1.29 +- 0.03 MeV at 1.35 MeV and 1.29 +- 0.02 MeV at 2.02 MeV

Neutron-proton analyzing power data at 7. 6, 12. 0, 14. 1, 16. 0, 18. 5 MeV

Energy Technology Data Exchange (ETDEWEB)

Weisel, G.J.; Tornow, W.; Howell, C.R.; Felsher, P.D.; Alohali, M.; Chen, Z.P.; Walter, R.L. (Duke Univ., Durham, NC (US) Triangle Universities Nuclear Lab., Durham, NC (US)); Lambert, J.M.; Treado, P.A. (Georgetown Univ., Washington, DC, (US))

1990-11-15

Neutron-Proton A{sub y} ({theta}) measurements have been made at 7.6, 12.0, 14.1, 16.0, and 18.5 MeV. A sensitivity study establishes the importance of A{sub y} ({theta}) in determining the {sup 3}P{sub 0,1,2} phase shifts in n-p scattering. The data are compared to the predictions of two phase-shift studies (one of which incorporates CIB effects), and the Paris and Bonn NN potentials.

Neutron capture cross-section measurements for 238U between 0.4 and 1.4 MeV

Science.gov (United States)

Krishichayan, Fnu; Finch, S. W.; Howell, C. R.; Tonchev, A. P.; Tornow, W.

2017-09-01

Neutron-induced radiative-capture cross-section data of 238U are crucial for fundamental nuclear physics as well as for Stewardship Science, for advanced-fuel-cycle calculations, and for nuclear astrophysics. Based on different techniques, there are a large number of 238U(n, γ) 239U cross-section data available in the literature. However, there is a lack of systematic and consistent measurements in the 0.1 to 3.0 MeV energy range. The goal of the neutron-capture project at TUNL is to provide accurate 238U(n, γ) 239U cross-section data in this energy range. The 238U samples, sandwiched between gold foils of the same size, were irradiated for 8-14 hours with monoenergetic neutrons. To avoid any contribution from thermal neutrons, the 238U and 197Au targets were placed inside of a thin-walled pill-box made of 238U. Finally, the whole pill-box was wrapped in a gold foil as well. After irradiation, the samples were gamma-counted at the TUNL's low-background counting facility using high-efficient HPGe detectors. The 197Au monitor foils were used to calculate the neutron flux. The experimental technique and 238U(n, γ) 239U cross-section results at 6 energies will be discussed during the meeting.

Measurement of 14 MeV neutron cross section of {sup 129}I with foil activation method

Energy Technology Data Exchange (ETDEWEB)

Murata, Isao; Nakano, Daisuke; Takahashi, Akito [Osaka Univ., Suita (Japan). Faculty of Engineering

1997-03-01

The {sup 129}I, which is one of the most famous fission products (FPs), is of very important concern from the standpoint of waste transmutation due to its extremely long half life. The accurate reaction cross section data of {sup 129}I induced by 14 MeV neutrons are indispensable when evaluating the performance to transmute it in a fusion reactor. However, there was no available experimental data reported until now. We measured 14 MeV neutron induced reaction cross sections of {sup 129}I to give the reference cross section data for evaluation of transmutation performance and nuclear data, using OKTAVIAN facility of Osaka university, Japan. Since the available amount of {sup 129}I as a sample is quite small, probably less than 1 mg, the foil activation method was adopted in the measurement. The sample was a sealed source of {sup 129}I and the {gamma}-rays from the irradiated sample were measured with a Hp-Ge detector. Several {gamma}-rays peaks which could be expected to be caused by two nuclear reactions of {sup 129}I(n,2n) and {sup 129}I(n,{gamma}) were observed. We confirmed that these peaks corresponded to those of {sup 128}I and {sup 130}I through ascertaining each energy and half life. From the measurement, the cross section of {sup 129}I(n,2n) and the effective production cross section of {sup 130}I produced by the {sup 129}I(n,{gamma}){sup 130}I reaction including the contribution of {sup 129}I(n,{gamma}){sup 130m}I reaction, that were estimated to be 1.1{+-}0.1 b and 0.032{+-}0.003 b, respectively at 14.8 MeV, were obtained with an acceptable accuracy of about 10 %, though the errors caused by the uncertainty of {gamma} decay scheme data still existed. The measured cross sections were compared with the evaluated nuclear data of JENDL-3.2 and ENDF/B-VI. For the {sup 129}I(n,2n) reaction, the evaluations overestimate the cross section by 30-40 %, while for the {sup 129}I(n,{gamma}) reaction, the evaluations underestimate by at least one order of magnitude

Benchmark experiments with 14 MeV neutrons transmitted through Pe, Fe, Ni and Al

International Nuclear Information System (INIS)

Tichy, M.; Kralik, M.; Pulpan, J.

1989-01-01

Spectra of 14 MeV neutrons transmitted through 7.6 cm of Pb, Fe, Ni and Al are presented. The target of d-t generator was placed to the center of the sphere from the tested material (outer diam. 24 cm). The detector (NE-213 scintillator diameter 5.08 cmx5.08 cm) was located at the distance 3 m and background was subtracted by means of 1 m iron cone. Measured pulse height spectra were processed by two methods and the results were compared with spectra calculated by means of the Blank and Brand codes using Endl and ENDF/B-IV libraries. Preliminary results show remarkable differences between calculation and experiment which requires additional calculations and an improvement of experimental equipment. (orig.)

Measurement method of activation cross-sections of reactions producing short-lived nuclei with 14 MeV neutrons

CERN Document Server

Kawade, K; Kasugai, Y; Shibata, M; Iida, T; Takahashi, A; Fukahori, T

2003-01-01

We describe a method for obtaining reliable activation cross-sections in the neutron energy range between 13.4 and 14.9 MeV for the reactions producing short-lived nuclei with half-lives between 0.5 and 30 min. We noted neutron irradiation fields and measured induced activities, including (1) the contribution of scattered low-energy neutrons, (2) the fluctuation of the neutron fluence rate during the irradiation, (3) the true coincidence sum effect, (4) the random coincidence sum effect, (5) the deviation in the measuring position due to finite sample thickness, (6) the self-absorption of the gamma-ray in the sample material and (7) the interference reactions producing the same radionuclides or the ones emitting the gamma-ray with the same energy of interest. The cross-sections can be obtained within a total error of 3.6%, when good counting statistics are achieved, including an error of 3.0% for the standard cross-section of sup 2 sup 7 Al (n, alpha) sup 2 sup 4 Na. We propose here simple methods for measuri...

Measurement and theoretical analysis of neutron-induced neutron-emission reactions of {sup 6}Li at 10 to 20 MeV region

Energy Technology Data Exchange (ETDEWEB)

Ibaraki, Masanobu; Baba, Mamoru; Matsuyama, Shigeo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

1998-06-01

We have measured the neutron elastic and inelastic scattering double-differential cross sections of {sup 6}Li at incident neutron energies of 11.5, 14.1 and 18.0 MeV. Based on this data, together with information from other works, a phenomenological neutron optical model potential (OMP) of {sup 6}Li was constructed to describe the total and elastic scattering cross sections from 5 MeV to several tens MeV. This potential also describes well the inelastic scattering to the 1st excited state (E{sub x} = 2.186 MeV) via the DWBA calculation with the macroscopic vibrational model. The continuum neutron energy spectra and angular distributions were then analyzed by the theory of final-state interaction extended to the DWBA form, with the assumption that the d-{alpha} interaction is dominant in the 3-body final state consisting of n, d and {alpha} particles. Such a calculation was found to be successful in explaining the major part of the low-excitation neutron spectra and angular distribution down to the Q-value region of -9 MeV, except for the Q-value range where the n-{alpha} quasi-free scattering will give a non-negligible contribution at forward angles. (author). 60 refs.

Neutron-neutron quasifree scattering in nd breakup at 10 MeV

Directory of Open Access Journals (Sweden)

Malone R.C.

2016-01-01

We are conducting new measurements of the cross section for nn QFS in nd breakup. The measurements are performed at incident neutron beam energies below 20 MeV. The neutron beam is produced via the 2H(d, n3He reaction. The target is a deuterated plastic cylinder. Our measurements utilize time-of-flight techniques with a pulsed neutron beam and detection of the two emitted neutrons in coincidence. A description of our initial measurements at 10 MeV for a single scattering angle will be presented along with preliminary results. Also, plans for measurements at other energies with broad angular coverage will be discussed.

Non-elastic cross-sections for neutron interactions with carbon and oxygen above 14 MeV

International Nuclear Information System (INIS)

Brenner, D.J.; Prael, R.E.

1985-01-01

In the light of the new generation of high energy (less than or equal to 80 MeV) neutron therapy facilities currently being tested, the need for neutron kerma factors in the range from 15 to 80 MeV on carbon and oxygen has become of urgent importance. Not enough experimental data currently exist or are likely to be measured soon, so a nuclear model is essential for interpolation or, less satisfactorily, extrapolation of available data. The use of a suitable model, applicable to light nuclei, is shown to be crucial. Such a model is described, and good agreement between its results and the experimental data in the energy range of interest is reported. Comparisons between the model predictions and the ENDF/B-V evaluation of the non-elastic cross section for carbon between 15 and 20 MeV indicate that a re-evaluation of ENDF is required. 35 refs., 12 figs., 6 tabs

Effect of pulsed dose in simultaneous and sequential irradiation of V-79 cells by 14.8 MeV neutrons and 60Co photons

International Nuclear Information System (INIS)

Higgins, P.D.; DeLuca, P.M. Jr.; Gould, M.N.; Schell, M.C.; Pearson, D.W.

1983-01-01

The effect of irradiating V-79 Chinese hamster ovary cells with a mixture of 40% 14.8-MeV neutrons and 60% 60 Co photons with simultaneous or sequential exposures is investigated. Target doses are obtained by irradiating cell samples with 3-minute-long pulses of alternating neutrons and photons (in the sequential case) or with mixed neutrons and photons followed by equal beam-off periods to insure equal total-exposure times for sequenced and simultaneous irradiations. We observe qualitative differences between the survival results under each beam configuration that confirms earlier observations

Effect of pulsed dose in simultaneous and sequential irradiation of V-79 cells by 14.8-MeV neutrons and 60Co photons

International Nuclear Information System (INIS)

Higgins, P.D.; DeLuca, P.M. Jr.; Gould, M.N.

1984-01-01

The effect of irradiating V-79 Chinese hamster cells with a mixture of 40% 14.8-MeV neutrons and 60% 69 Co photons with simultaneous or sequential exposures is investigated. Sample doses are obtained by irradiating cells with alternating 3-min pulses of neutrons and photons (in the sequential case) or with mixed neutrons and photons followed by equal beam-off periods to ensure equal total exposure times for sequential and simultaneous irradiations. Differences between the survival results under each beam configuration that are consistent with previous observations with nonpulsed irradiations are observed

Use of 13.5-MeV neutrons for protein determination in grain crops

International Nuclear Information System (INIS)

Barit, I.A.; Kuz'min, L.E.; Makarov, S.A.; Vozhzhov, V.F.; Pronman, I.M.

1989-01-01

One of the main objectives of the Food Supply Program, i.e., that of improving the quality of crop production, is bound up intimately with the intensification of work on the selection and genetics of high-protein grain and legume crops. High-protein stains cannot be isolated without the proper analytical service for mass testing of the nitrogen content in the grain, which is one of the main elements of protein. The neutron-activation method of nitrogen determination is based on the use of the 14 N(n, 2n) 13 N nuclear reaction (E th = 11.3 MeV) with an average neutron energy of ∼14.5 MeV. In this work the authors consider a new variant of the neutron-activation method of determining nitrogen in grain and legume crops. The method is based on the use of monoenergetic neutrons with an energy of ∼13.5 MeV, generated in relatively thin titanium-tritium targets by a mass-separated deuteron beam from neutron generators operating at 150-300 kV, in order to eliminate the interference of the reaction 39 K(n, 2n) 38 K (E thr = 13.4 MeV). The present method has been used to determine the protein content (mass %) in different grains and legumes at the All-Union Selection-Genetic Institute of the Lenin Academy of Agricultural Sciences. The correctness of the analysis was checked by comparison with the data of chemical analysis. The discrepancy between the results of the two methods does not exceed 3%, which is within the limits of the error of measurement of Δ and K s.r

In vivo skin leptin modulation after 14 MeV neutron irradiation: a molecular and FT-IR spectroscopic study

Energy Technology Data Exchange (ETDEWEB)

Cestelli Guidi, M.; Mirri, C.; Marcelli, A. [Laboratori Nazionali di Frascati - INFN, Frascati, Rome (Italy); Fratini, E.; Amendola, R. [ENEA, UT BIORAD-RAB, Rome (Italy); Licursi, V.; Negri, R. [Universita La Sapienza, Dip. Biologia e Biotecnologie ' ' Charles Darwin' ' , Rome (Italy)

2012-09-15

This paper discusses gene expression changes in the skin of mice treated by monoenergetic 14 MeV neutron irradiation and the possibility of monitoring the resultant lipid depletion (cross-validated by functional genomic analysis) as a marker of radiation exposure by high-resolution FT-IR (Fourier transform infrared) imaging spectroscopy. The irradiation was performed at the ENEA Frascati Neutron Generator (FNG), which is specifically dedicated to biological samples. FNG is a linear electrostatic accelerator that produces up to 1.0 x 10{sup 11} 14-MeV neutrons per second via the D-T nuclear reaction. The functional genomic approach was applied to four animals for each experimental condition (unirradiated, 0.2 Gy irradiation, or 1 Gy irradiation) 6 hours or 24 hours after exposure. Coregulation of a subclass of keratin and keratin-associated protein genes that are physically clustered in the mouse genome and functionally related to skin and hair follicle proliferation and differentiation was observed. Most of these genes are transiently upregulated at 6 h after the delivery of the lower dose delivered, and drastically downregulated at 24 h after the delivery of the dose of 1 Gy. In contrast, the gene coding for the leptin protein was consistently upregulated upon irradiation with both doses. Leptin is a key protein that regulates lipid accumulation in tissues, and its absence provokes obesity. The tissue analysis was performed by monitoring the accumulation and the distribution of skin lipids using FT-IR imaging spectroscopy. The overall picture indicates the differential modulation of key genes during epidermis homeostasis that leads to the activation of a self-renewal process at low doses of irradiation. (orig.)

In vivo skin leptin modulation after 14 MeV neutron irradiation: a molecular and FT-IR spectroscopic study.

Science.gov (United States)

Cestelli Guidi, M; Mirri, C; Fratini, E; Licursi, V; Negri, R; Marcelli, A; Amendola, R

2012-09-01

This paper discusses gene expression changes in the skin of mice treated by monoenergetic 14 MeV neutron irradiation and the possibility of monitoring the resultant lipid depletion (cross-validated by functional genomic analysis) as a marker of radiation exposure by high-resolution FT-IR (Fourier transform infrared) imaging spectroscopy. The irradiation was performed at the ENEA Frascati Neutron Generator (FNG), which is specifically dedicated to biological samples. FNG is a linear electrostatic accelerator that produces up to 1.0 × 10(11) 14-MeV neutrons per second via the D-T nuclear reaction. The functional genomic approach was applied to four animals for each experimental condition (unirradiated, 0.2 Gy irradiation, or 1 Gy irradiation) 6 hours or 24 hours after exposure. Coregulation of a subclass of keratin and keratin-associated protein genes that are physically clustered in the mouse genome and functionally related to skin and hair follicle proliferation and differentiation was observed. Most of these genes are transiently upregulated at 6 h after the delivery of the lower dose delivered, and drastically downregulated at 24 h after the delivery of the dose of 1 Gy. In contrast, the gene coding for the leptin protein was consistently upregulated upon irradiation with both doses. Leptin is a key protein that regulates lipid accumulation in tissues, and its absence provokes obesity. The tissue analysis was performed by monitoring the accumulation and the distribution of skin lipids using FT-IR imaging spectroscopy. The overall picture indicates the differential modulation of key genes during epidermis homeostasis that leads to the activation of a self-renewal process at low doses of irradiation.

Design Concept of a Seal-off Type 14 MeV Neutron Generator of 10''1''1n/s Range

Energy Technology Data Exchange (ETDEWEB)

In, S. R.; Oh, B. H. [KAERI, Daejeon (Korea, Republic of)

2015-05-15

The total neutron fluence during the life time is expected to be around 10MW·yr/m''2 which may cause a damage of -100 dpa in materials. To estimate the adaptability of candidate materials in a few years, a 14MeV neutron source with a flux level of 3 - 5 x 10''1''8 n/s·m''2, which is the goal of the IFMIF facility costing more than ¤1000M, is necessitated. The problem in making an intense neutron generator of beam target type is really not on the neutron production rate, but on the huge heat generated in the target, because the fusion power is only one of thousands of beam power exerted on the target. We have a plan to develop neutron generators step by step from a 10''8 n/s level. The final goal is establishing a 14MeV neutron irradiation facility at 10''1''4 intensity level.. Up to the 10''1''0 n/s level, there occurs basically no critical thermal problem, because beam power density is in the range of tens W/cm''2. The neutron generator designed in a sealed-off type because of tritium safety is mainly composed of an ion source, target, reaction chamber, and getter pump.. The major design concepts for the neutron generator with the neutron production rate of 10''1''1 n/s range were presented. The specifications of the ion source, target and getter have been determined for attaining the goal of the neutron generation rate.

Spallation and 14-MeV neutron irradiation of stabilized NbTi superconductors

International Nuclear Information System (INIS)

Hahn, P.; Brown, B.S.; Weber, H.W.; Guinan, M.W.

1983-08-01

The results on 5 K irradiation available so far may be summarized as follows. (1) Increases of j/sub c/ following neutron irradiation occur only in conductors which are far from the optimal metallurgical treatments. (2) The changes of j/sub c/ following neutron irradiation and a thermal cycle to room temperature are small and in most cases comparable to the results obtained after 77 K irradiation. (3) The data available so far indicate that the degradation of j/sub c/ at 8 T is larger by about 5 to 10% than the corresponding changes at 5 T at a neutron fluence of 1.3 x 10 22 m -2 (E > 0.1 MeV). (4) The increase of Cu-resistivity is significant even after a thermal cycle to room temperature and requires design changes for a stable magnet operation

The study of 90 deg. gamma ray production cross sections for interactions of 14.9 Mev neutrons with C, Al, V, Fe, Co, Nb samples

International Nuclear Information System (INIS)

Tang Lin; Yan Yiming; Zhou Hongyu; Wen Shenlin; Wang Qi; Sun Shuxu; Ding Xiaoji; Wang Wanhong

1987-04-01

The (n,xr) reactions have been studied for incident neutron energy 14.9 Mev and for the samples C, Al, V, Fe, Co and Nb. The pulsed beam Time-of-Flight technique was adopted to discriminate neutrons and de-excitation r-rays and to improve the background conditions of the experiment. 90 deg. differential gamma production cross sections as the results of experiments are presented. Due to very low background many new r-rays peaks have been obtained. (author). 14 refs, 12 figs, 1 tab

A new empirical formula for 14-15 MeV neutron-induced (n, p) reaction cross sections

International Nuclear Information System (INIS)

Tel, E; Sarer, B; Okuducu, S; Aydin, A; Tanir, G

2003-01-01

In this study, we have suggested a new empirical formula to reproduce the cross sections of the (n, p) reactions at 14-15 MeV for the neutron incident energy. This formula obtained using the asymmetry parameters represents a modification to the original formula of Levkovskii. The resulting modified formulae yielded cross sections, representing smaller χ 2 deviations from experimental values, and values much closer to unity as compared with those calculated using Levkovskii's original formula. The results obtained have been discussed and compared with the existing formulae, and found to be well in agreement, when used to correlate the available experimental σ(n, p) data of different nuclei

Neutron-neutron quasifree scattering in nd breakup at 10 MeV

Science.gov (United States)

Malone, R. C.; Crowe, B.; Crowell, A. S.; Cumberbatch, L. C.; Esterline, J. H.; Fallin, B. A.; Friesen, F. Q. L.; Han, Z.; Howell, C. R.; Markoff, D.; Ticehurst, D.; Tornow, W.; Witała, H.

2016-03-01

The neutron-deuteron (nd) breakup reaction provides a rich environment for testing theoretical models of the neutron-neutron (nn) interaction. Current theoretical predictions based on rigorous ab-initio calculations agree well with most experimental data for this system, but there remain a few notable discrepancies. The cross section for nn quasifree (QFS) scattering is one such anomaly. Two recent experiments reported cross sections for this particular nd breakup configuration that exceed theoretical calculations by almost 20% at incident neutron energies of 26 and 25 MeV [1, 2]. The theoretical values can be brought into agreement with these results by increasing the strength of the 1S0 nn potential matrix element by roughly 10%. However, this modification of the nn effective range parameter and/or the 1S0 scattering length causes substantial charge-symmetry breaking in the nucleon-nucleon force and suggests the possibility of a weakly bound di-neutron state [3]. We are conducting new measurements of the cross section for nn QFS in nd breakup. The measurements are performed at incident neutron beam energies below 20 MeV. The neutron beam is produced via the 2H(d, n)3He reaction. The target is a deuterated plastic cylinder. Our measurements utilize time-of-flight techniques with a pulsed neutron beam and detection of the two emitted neutrons in coincidence. A description of our initial measurements at 10 MeV for a single scattering angle will be presented along with preliminary results. Also, plans for measurements at other energies with broad angular coverage will be discussed.

Cross-sections for formation of 99mTc through natRu(n,x) 99mTc reaction induced by neutrons at 13.5 and 14.8 MeV

International Nuclear Information System (INIS)

Luo Junhua; Han Jiuning; Tuo Fei; Kong Xiangzhong; Liu Rong; Jiang Li

2012-01-01

The cross-sections for formation of metastable state of 99 Tc ( 99m Tc, 140.511 keV, 6.01 h) through nat Ru(n,x) 99m Tc reaction induced by 13.5 MeV and 14.8 MeV neutrons were measured. Fast neutrons were produced via the 3 H(d,n) 4 He reaction on the K-400 neutron generator. Induced gamma activities were measured by a high-resolution gamma-ray spectrometer with a high-purity germanium (HpGe) detector. Measurements were corrected for gamma-ray attenuations, dead time and fluctuation of neutron flux. Data for nat Ru(n,x) 99m Tc reaction cross sections are reported to be 9.6±1.5 and 9.2±1.1 mb at 13.5±0.2 and 14.8±0.2 MeV incident neutron energies, respectively. Results were compared with the data by other authors. - Highlights: ► D–T neutron source was used to measure cross sections using activation method. ► 27 Al(n,α) 24 Na was used as the monitor for the measurement. ► Cross-sections for formation of 99m Tc through nat Ru(n,x) 99m Tc were measured. ► Data for nat Ru(n,x) 99m Tc reaction cross sections are reported. ► The results were discussed and compared with experimental data in the literature.

Determination of the emission rate for the 14 MeV neutron generator with the use of radio-yttrium

Directory of Open Access Journals (Sweden)

Laszynska Ewa

2015-06-01

Full Text Available The neutron emission rate is a crucial parameter for most of the radiation sources that emit neutrons. In the case of large fusion devices the determination of this parameter is necessary for a proper assessment of the power release and the prediction for the neutron budget. The 14 MeV neutron generator will be used for calibration of neutron diagnostics at JET and ITER facilities. The stability of the neutron generator working parameters like emission and angular homogeneity affects the accuracy of calibration other neutron diagnostics. The aim of our experiment was to confirm the usefulness of yttrium activation method for monitoring of the neutron generator SODERN Model: GENIE 16. The reaction rate induced by neutrons inside the yttrium sample was indirectly measured by activation of the yttrium sample, and then by means of the γ-spectrometry method. The pre-calibrated HPGe detector was used to determine the yttrium radioactivity. The emissivity of neutron generator calculated on the basis of the measured radioactivity was compared with the value resulting from its electrical settings, and both of these values were found to be consistent. This allowed for a positive verification of the reaction cross section that was used to determine the reaction rate (6.45 × 10−21 reactions per second and the neutron emission rate (1.04 × 108 n·s−1. Our study confirms usefulness of the yttrium activation method for monitoring of the neutron generator.

Gamma-ray production cross-sections for the interactions of 14.9 MeV neutrons with Si, Cu, Nb and Pb

International Nuclear Information System (INIS)

Fan Guoying

1991-12-01

Gamma rays produced in the interactions of 14.9 MeV neutrons with Si, Cu, Nb and Pb targets were studied. The neutron beam was produced with the T(d,n)He reaction using 300 KeV Cockroft-Walton accelerator. Absolute neutron flux was determined by the associated particle technique. The time-of-flight technique was used to reduce the background. The FWHM of neutron pulses was 1.5 ns. A Ge(Li) detector was used for gamma-ray detection. 39 gamma lines for Si, 39 gamma lines for Cu, 79 for Nb and 39 for Pb were detected. Most of these gamma rays were emitted in (n,γ), (n,n') and (n,2n) reactions. The measurements were made at 40 deg. C, 55 deg. C, 125 deg. C and 140 deg. C relative to the incident neutron beam. The results are presented in the form of the data tables. 9 refs, 11 figs, 19 tabs

Relative Biological Effectiveness of 14-MeV Fast Neutrons to Co{sup 60} Gamma-Rays in Einkorn Wheat; Efficacite Biologique Relative des Neutrons Rapides de 14 MeV par Rapport aux Rayons Gamma de {sup 60}Co sur l'Engrain; Otnositel'naya biologicheskaya ehffektivnost' bystrykh nejtronov s ehnergiej 14 MeV i gamma-luchej CO{sup 60} pri ikh dejstvii na pshenitsu odnozernyanku; EBR de los Neutrones Rapidos de 14 MeV y de los Rayos Gamma del {sup 60}Co en el Trigo Escanda Menor

Energy Technology Data Exchange (ETDEWEB)

Fujii, T. [National Institute of Genetics, Misima (Japan)

1964-05-15

The author investigated the RBE of 14 MeV neutrons to Co{sup 60} gamma-rays by using the specific locus method in Einkorn wheat. F{sub 1} seeds from the cross between the original strain and a chlorina mutant were used in this study (chlorina mutant was obtained as a single recessive mutant from X-irradiation; it was uniformly light green from seedling stage to maturity with relatively high survival rate and fertility). The F{sub 1} plants showed normal green colour and normal growth habit. Dormant F{sub 1} seeds were irradiated at 0.5 , 1.0 and 1.4 krad of fast neutrons ami 4.3 , 8.6 and 12.9 krad of gamma-rays. Mutations from dominant normal green to chlorina occurred by both irradiations and appeared in the leaves and stems of the heterozygotic Xi plants as longitudinal stripes. Around 80% of seeds germinated in the control lot and in the lowest dosage lots from both neutron and gamma-ray irradiations, and germination percentages were gradually decreased with increasing dosage of both kinds of radiation. Moreover, a similar tendency was observed at the early stage as to seedling growth which was gradually inhibited with increasing dosage. According to these results, neutron irradiation was about 13 times more effective than that of gamma-rays. Survival rate in the non-irradiated control was about 90% and about 60-80% of germinated seedlings survived in 0.5 and 1.0 krad lots from neutron irradiation and all lots irradiated by gamma-rays. On the other hand, only about 4% of germinated seedlings survived in the highest neutron lot. No mutation was observed in the control lot, and the number of plants which contained striped tillers increased with increasing dosage of both kinds of radiation. Mutated tillers were observed in about 15% of surviving plants obtained at the lowest dosage of neutron irradiation and a similar frequency was observed from the highest dosage of gamma-rays. RBE of 14 MeV neutrons to Co{sup 60} gamma-rays seemed to be at least 20 for the

Measurement of cross sections producing short-lived nuclei by 14 MeV neutron. Br, Te, Dy, Ho, Yb

Energy Technology Data Exchange (ETDEWEB)

Sakane, H.; Matsumoto, T.; Yamamoto, H.; Kawade, K. [Nagoya Univ. (Japan); Iida, T.; Takahashi, A.

1997-03-01

Nine neutron activation cross sections producing the nuclei with half-lives between 2 min and 57 min have been measured at energy range between 13.4 and 14.9 MeV for Br, Te, Dy, Ho, Yb. The cross sections of {sup 81}Br(n,p){sup 81m}Se, {sup 128}Te(n,p){sup 128m}Sb, {sup 128}Te(n,{alpha}){sup 125m}Sn, {sup 164}Dy(n,p){sup 164}Tb, {sup 165}Ho(n,{alpha}){sup 162}Tb, {sup 176}Yb(n,p){sup 176}Tm were newly obtained at the six energy points between 13.4-14.9 MeV, although the previous results have been obtained at one energy point. {sup 79}Br(n,2n){sup 78}Br, {sup 164}Dy(n,p){sup 164}Tb are compared with evaluated data of JENDL-3.2. The evaluations for these reactions agree reasonably well with experimental results. The cross sections of (n,p) reaction are compared with systematics by Kasugai et. al. The systematics agrees with experimental results. (author)

Activation cross section measurement at neutron energy from 13.3 to 14.9 MeV using FNS facility

Energy Technology Data Exchange (ETDEWEB)

Kasugai, Yoshimi; Ikeda, Yujiro; Uno, Yoshitomo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Yamamoto, Hiroshi; Kawade, Kiyoshi [Nagoya Univ. (Japan)

2001-03-01

Sixty activation cross sections have been measured in the neutron energy between 13.4 and 14.9 MeV using intense D-T neutrons source (Fusion Neutronics Source, FNS) at JAERI. The following reactions are included in this work: (1) 32 reactions mainly for lanthanide isotopes, (2) 19 reactions for short-lived products (the half-lives are from 1 s to 20 min) and (3) 9 (n, n{alpha}) reactions. The experimental results were compared with the data reported previously and the evaluated data of ENDF/B-VI Rev. 4, JENDL-3.2 and FENDL/A-2.0. The present data for the (n, p) and (n, {alpha}) reactions were compared with the values estimated by using the empirical formulae proposed by our group in order to validate the systematics for the reactions for the lanthanide isotopes. Systematic trend of (n, n{alpha}) reactions were discussed based on the present data. (author)

A new calculation method adapted to the experimental conditions for determining samples γ-activities induced by 14 MeV neutrons

International Nuclear Information System (INIS)

Rzama, A.; Erramli, H.; Misdaq, M.A.

1994-01-01

Induced gamma-activities of different disk shaped irradiated samples and standards with 14 MeV neutrons have been determined by using a Monte Carlo calculation method adapted to the experimental conditions. The self-absorption of the multienergetic emitted gamma rays has been taken into account in the final samples activities. The influence of the different activation parameters has been studied. Na, K, Cl and P contents in biological (red beet) samples have been determined. ((orig.))

Actinide neutron-induced fission up to 20 MeV

International Nuclear Information System (INIS)

Maslov, V.M.

2001-01-01

Fission and total level densities modelling along with double-humped fission barrier parameters allow to describe available actinide neutron-induced fission cross section data in the incident neutron energy range of ∼ 10 keV - 20 MeV. Saddle asymmetries relevant to shell correction model calculations influence fission barriers, extracted by cross section data analysis. The inner barrier was assumed axially symmetric in case of U, Np and Pu neutron-deficient nuclei. It is shown that observed irregularities in neutron-induced fission cross section data in the energy range of 0.5-3 MeV could be attributed to the interplay of few-quasiparticle excitations in the level density of fissioning and residual nuclei. Estimates of first-chance fission cross section and secondary neutron spectrum model were validated by 238 U fission, (n,2n) and (n,3n) data description up to 20 MeV. (author)

Actinide neutron-induced fission up to 20 MeV

Energy Technology Data Exchange (ETDEWEB)

Maslov, V M [Radiation Physics and Chemistry Problems Institute, Minsk-Sosny (Belarus)

2001-12-15

Fission and total level densities modelling along with double-humped fission barrier parameters allow to describe available actinide neutron-induced fission cross section data in the incident neutron energy range of {approx} 10 keV - 20 MeV. Saddle asymmetries relevant to shell correction model calculations influence fission barriers, extracted by cross section data analysis. The inner barrier was assumed axially symmetric in case of U, Np and Pu neutron-deficient nuclei. It is shown that observed irregularities in neutron-induced fission cross section data in the energy range of 0.5-3 MeV could be attributed to the interplay of few-quasiparticle excitations in the level density of fissioning and residual nuclei. Estimates of first-chance fission cross section and secondary neutron spectrum model were validated by {sup 238}U fission, (n,2n) and (n,3n) data description up to 20 MeV. (author)

Analysis of tritium production in concentric spheres of oralloy and 6LiD irradiated by 14-MeV neutrons

International Nuclear Information System (INIS)

Fawcett, L.R. Jr.; Roberts, R.R. II; Hunter, R.E.

1988-03-01

Tritium production and activation of radiochemical detector foils in a sphere of 6 LiD with an oralloy core irradiated by a central source of 14-MeV neutrons have been calculated and compared with experimental measurements. The experimental assembly consisted of an oralloy sphere surrounded by three solid 6 LiD concentric shells with ampules of 6 LiH and 7 LiH and activation foils located in several positions throughout the assembly. The Los Alamos Monte Carlo Neutron Photon Transport Code (MCNP) was used to calculate neutron transport throughout the system, tritium production in the ampules, and foil activation. The overall experimentally observed-to-calculated ratios of tritium production were 0.996 +- 2.5% in 6 Li ampules and 0.903 +- 5.2% in 7 Li ampules. Observed-to-calculated ratios for foil activation are also presented. 11 refs., 4 figs., 7 tabs

Monte Carlo calculation of the cross-section of single event upset induced by 14MeV neutrons

International Nuclear Information System (INIS)

Li, H.; Deng, J.Y.; Chang, D.M.

2005-01-01

High-density static random access memory may experience single event upsets (SEU) in neutron environments. We present a new method to calculate the SEU cross-section. Our method is based on explicit generation and transport of the secondary reaction products and detailed accounting for energy loss by ionization. Instead of simulating the behavior of the circuit, we use the Monte Carlo method to simulate the process of energy deposition in sensitive volumes. Thus, we do not need to know details about the circuit. We only need a reasonable guess for the size of the sensitive volumes. In the Monte Carlo simulation, the cross-section of SEU induced by 14MeV neutrons is calculated. We can see that the Monte Carlo simulation not only can provide a new method to calculate SEU cross-section, but also can give a detailed description about random process of the SEU

Determination of relative krypton fission product yields from 14 MeV neutron induced fission of 238U at the National Ignition Facility.

Science.gov (United States)

Edwards, E R; Cassata, W S; Velsko, C A; Yeamans, C B; Shaughnessy, D A

2016-11-01

Precisely-known fission yield distributions are needed to determine a fissioning isotope and the incident neutron energy in nuclear security applications. 14 MeV neutrons from DT fusion at the National Ignition Facility induce fission in depleted uranium contained in the target assembly hohlraum. The fission yields of Kr isotopes (85m, 87, 88, and 89) are measured relative to the cumulative yield of 88 Kr and compared to previously tabulated values. The results from this experiment and England and Rider are in agreement, except for the 85m Kr/ 88 Kr ratio, which may be the result of incorrect nuclear data.

Cross section measurements of the (n,2n) reaction with 14 MeV neutrons

Energy Technology Data Exchange (ETDEWEB)

Kaji, Harumi; Shiokawa, Takanobu [Tohoku Univ., Sendai (Japan). Faculty of Science; Suehiro, Teruo; Yagi, Masuo

1975-07-01

Cross sections are measured for the reactions /sup 64/Zn(n, 2n)/sup 63/Zn, /sup 75/As(n, 2n)/sup 74/As, /sup 79/Br(n, 2n)/sup 78/Br, /sup 90/Zr(n, 2n)/sup 89/Zr, /sup 141/Pr(n, 2n)/sup 140/Pr and /sup 144/Sm(n, 2n)/sup 143/Sm by activation method in the energy range 13.5-14.8 MeV. The cross sections are determined relatively to the cross section for the /sup 63/Cu(n, 2n)/sup 62/Cu and /sup 19/F(n, 2n)/sup 18/F reactions. Before the cross section measurement, incident-neutron energies are measured by recoil proton method. The results of the cross sections are compared with data existing in the literatures and are discussed with reference to the theory of Weisskopf and Ewing.

Double differential cross-sections of (n,{alpha}) reactions in aluminium and nickel at 14.77 MeV neutrons

Energy Technology Data Exchange (ETDEWEB)

Lalremruata, B.; Dhole, S.D. [Department of Physics, University of Pune, Pune-411007 (India); Ganesan, S. [Reactor Physics Design Division, BARC, Mumbai-400085 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune-411007 (India)], E-mail: vnb@physics.unipune.ernet.in

2009-04-15

The double differential cross-sections (DDX) for the emission of alpha particles from {sup 27}Al(n,{alpha}){sup 24}Na and Ni(n,{alpha}) reactions induced by 14.77 MeV neutrons were estimated from the alpha particle spectra recorded at 30 deg., 50 deg., 90 deg., 110 deg. angles for aluminium, and at 20 deg., 45 deg., 90 deg., 110 deg. for natural nickel. The results indicate that the alpha particles below and around the most probable energies ({approx}6.3 MeV from aluminium and {approx}8 MeV from natural nickel) are emitted predominantly through the compound nucleus formation process, and the higher energy alpha particles are emitted through the pre-equilibrium or the direct reaction. In general, the measured double-differential cross-sections are in agreement with the theoretical cross-sections estimated using Talys-1.0 and Preco2007 computer programs. The present value of the level density parameter for {sup 24}Na is close to the literature value and, therefore, these results reveal consistency in the alpha particle spectra recorded with a single silicon surface barrier detector at different scattering angles.

Measurements of double-differential neutron emission cross sections of Nb and Bi for 11.5 MeV neutrons

Energy Technology Data Exchange (ETDEWEB)

Ibaraki, Masanobu; Matsuyama, Shigeo; Soda, Daisuke; Baba, Mamoru; Hirakawa, Naohiro [Tohoku Univ., Sendai (Japan). Faculty of Engineering

1997-03-01

Double-differential neutron emission cross sections (DDXs) of Nb and Bi have been measured for 11.5MeV neutrons using the {sup 15N}(d,n){sup 16}O quasi-monoenergetic neutron source at Tohoku University 4.5MV Dynamitron facility. For En`>6MeV, DDXs were measured by the conventional TOF method (single-TOF:S-TOF). For En`<6MeV, where the S-TOF spectra were distorted by the background neutrons, we adopted a double-TOF method (D-TOF). By applying D-TOF method, we obtained DDXs down to 1MeV. (author)

Empirical formulae for 14.5 MeV (n,p) cross sections

International Nuclear Information System (INIS)

Selvi, S.; Erbil, H.H.

1989-12-01

Six empirical formulae of the (n,p) cross sections for 14.5-MeV neutrons were obtained with respect to even and odd (N-Z) values, depending on the effective Q-Value, the Coulomb barrier height, the threshold and incident neutron energies and the mass number of the target. These formulae were compared with the experimental values. The present calculations fit the experimental results quite well compared to those predicted by the previous workers. (author). 8 refs, 1 fig., 1 tab

An attempt of application of short lived 44K activity induced in the 44Ca(n,p)44K reaction using 14 MeV neutrons for total body calcium assessment in human subject

International Nuclear Information System (INIS)

Haratym, Z.; Kempisty, T.; Mikolajewski, S.; Rurarz, E.

1999-01-01

The status of in vivo neutron activation analysis techniques for the measurement of total body calcium in human subject is reviewed. Relevant data on the nuclear characteristics of calcium isotopes during interaction with neutrons ranging from slow up to 14 MeV neutrons are presented. Physical aspects of the measurement of in vivo total body calcium (TBCa) using 44 K activity induced in the 44 Ca(n,p) 44 K(T 1/2 =22.3 min) reaction by 14 MeV neutrons are discussed. The measurement of delayed γ-ray emitted during decay of activities induced in enriched 44 Ca, nat Ca, phantom filled with water solution of natural calcium and skeletal arm are considered. Results of measurements on the phantom and skeletal arm indicate a possibility to measure the TBCa using the 44 K activity. (author)

SIMULATED 8 MeV NEUTRON RESPONSE FUNCTIONS OF A THIN SILICON NEUTRON SENSOR.

Science.gov (United States)

Takada, Masashi; Matsumoto, Tetsuro; Masuda, Akihiko; Nunomiya, Tomoya; Aoyama, Kei; Nakamura, Takashi

2017-12-22

Neutron response functions of a thin silicon neutron sensor are simulated using PHITS2 and MCNP6 codes for an 8 MeV neutron beam at angles of incidence of 0°, 30° and 60°. The contributions of alpha particles created from the 28Si(n,α)25Mg reaction and the silicon nuclei scattered elastically by neutrons in the silicon sensor have not been well reproduced using the MCNP6 code. The 8 MeV neutron response functions simulated using the PHITS2 code with an accurate event generator mode are in good agreement with experimental results and include the contributions of the alpha particles and silicon nuclei. © The Author(s) 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Neutron total cross section measurements in the energy region from 47 keV to 20 MeV

International Nuclear Information System (INIS)

Poenitz, W.P.; Whalen, J.F.

1983-05-01

Neutron total cross sections were measured for 26 elements. Data were obtained in the energy range from 47 keV to 20 MeV for 11 elements in the range of light-mass fission products. Previously reported measurements for eight heavy and actinide isotopes were extended to 20 MeV. Data were also obtained for Cu (47 keV to 1.4 MeV) and for Sc, Zn, Nd, Hf, and Pt (1.8 to 20 MeV). The present work is part of a continuing effort to provide accurate neutron total cross sections for evaluations and for optical-model parameteriztions. The latter are required for the derivation of other nuclear-data information of importance to applied programs. 37 references

High-sensitive detection by direct interrogation of 14 MeV Acc neutrons, (1). Uranium-contained metal matrix in a waste dram

International Nuclear Information System (INIS)

Haruyama, Mitsuo; Takase, Misao; Tobita, Hiroshi; Mori, Takamasa

2004-01-01

Previously, authors reported that the 14 MeV-neutron direct interrogation method has made possible measure for the discrimination of clearance levels of concrete solidification uranium waste. In this paper, applicability of the method to metal waste matrix is discussed based on the results of simulation experiments by the continuation energy Monte Carlo calculation code (MVP). The problem is that self-neutron moderation effect in a waste cannot be expected when a waste matrix is metal. To solve this, a moderator is adopted so as to surround a metal waste drum and to slow down suitably a 14 MeV neutrons. The simulation calculation showed that this effect is satisfactorily large. The detection limit of radioactivity concentration to 4.5% enriched uranium has been found to be 0.0973 Bq/g in the metal waste model of 215.59 kg gross weight, in which 61 pipes are stuffed into its drum. Moreover, the position-dependent sensitivity difference in a metal waste drum can be settled as small as to ±13.5%. In conclusion, it can be said that 14 MeV-neutron direct interrogation method can be applied to the waste of a metal system: the detection sensitivity is high enough and the position-dependent sensitivity difference is small admittedly. Hence the method can be applied also to discrimination measurement of the clearance level of metal uranium waste. (author)

Volumetric Heat Generation and Consequence Raise in Temperature Due to Absorption of Neutrons from Thermal up to 14.9 MeV Energies

CERN Document Server

Massoud, E

2003-01-01

In this work, the heat generation rate and the consequence rise in temperature due to absorption of all neutrons from thermal energies (E<0.025) up to 14.9 MeV in water, paraffin wax, ordinary concrete and heavy concrete and heavy concrete as some selected hydrogenous materials are investigated. The neutron flux distributions are calculated by both ANISN-code and three group method in which the fast neutrons are expressed by the removal cross section concept while the other two groups (epithermal and thermal) are treated by the diffusion equation. The heat generation can be calculated from the neutron macroscopic absorption of each material or mixture multiplied by the corresponding neutron fluxes. The rise in temperature is then calculated by using both of the heat generation and the thermal conductivity of the selected materials. Some results are compared with the available experimental and theoretical data and a good agreement is achieved.

Neutron-photon multigroup cross sections for neutron energies up to 400 MeV: HILO86R

International Nuclear Information System (INIS)

Kotegawa, Hiroshi; Nakane, Yoshihiro; Hasegawa, Akira; Tanaka, Shun-ichi

1993-02-01

A macroscopic multigroup cross section library of 66 neutron and 22 photon groups for neutron energies up to 400 MeV: HILO86R is prepared for 10 typical shielding materials; water, concrete, iron, air, graphite, polyethylene, heavy concrete, lead, aluminum and soil. The library is a revision of the DLC-119/HILO86, in which only the cross sections below 19.6 MeV have been exchanged with a group cross section processed from the JENDL-3 microscopic cross section library. In the HILO86R library, self shielding factors are used to produce effective cross sections for neutrons less than 19.6 MeV considering rather coarse energy meshes. Energy spectra and dose attenuation in water, concrete and iron have been compared among the HILO, HILO86 and HILO86R libraries for different energy neutron sources. Significant discrepancy has been observed in the energy spectra less than a couple of MeV energy in iron among the libraries, resulting large difference in the dose attenuation. The difference was attributed to the effect of self-shielding factor, namely to the difference between infinite dilution and effective cross sections. Even for 400 MeV neutron source the influence of the self-shielding factor is significant, nevertheless only the cross sections below 19.6 MeV are exchanged. (author)

Determination of phosphorus and calcium in biological samples by activation with 14 MeV neutrons; Determinacao de fosforo e calcio em amostras biologicas por ativacao com neutrons de 14 MeV

Energy Technology Data Exchange (ETDEWEB)

Berretta, Jose Roberto

1995-07-01

Analytical methods for phosphorus and calcium in biological samples by means of activation with 14 MeV neutrons, using the Van de Graaff accelerator from the Instituto de Pesquisas Energeticas e Nucleares, SP, Brazil are developed. For phosphorus analysis, powder samples were pressed into pellets, weighed and transferred to polyethylene plastic envelopes. The pellets with cadmium shielding were irradiated under a fast neutron flux for 5 to 10 minutes, and further counted in a HPGe detector for 5 minutes. Calcium analysis was performed by cyclic irradiation. Samples were irradiated for 10 minutes. After a decay time of 2 minutes, gamma counting was performed for 10 minutes. After a decay time of 2 minutes, a new irradiation ws made. The irradiation cycle was repeated 5 times and the counting spectrum obtained in each cycle was accumulated in the multi channel analyser. The variation of the neutron flux was followed by using a BF{sub 3} detector calibrated with and aluminium monitor. By means of the gamma spectrum and the neutron counting of the BF{sub 3} detector it was possible to estimate phosphorus and calcium concentrations in the sample analyzed. The methods were checked in the reference samples from the International Atomic Energy Agency and in commercial samples of powder milk, fertilizer and animal bone. Phosphorus contents in bone (A3/74) and milk (A-11) reference materials were (15.6 +- 1.8%) and (0.9 +- 0.1)%, respectively. These values are in good agreement to the certified values (15.5 +- 0.5)% and (0.910 +- 0.102)%, respectively. Calcium analysis carried out in bone (A3/74) presented a value of (31.8+-4.1)% and the certified value was of (31.3 +- 0.3)%. Detection limits for phosphorus and calcium were determined in different analyzed samples. The agreement of the results obtained with the certified values confirmed the suitability of the methods for phosphorus and calcium analysis. The methods are fast and laborious chemical procedures are not required

Study of the production of uranium-233 in natural thorium subjected to a neutron flux of 14 MeV

International Nuclear Information System (INIS)

Abel, G.; Martel, J.G.; St Germain, J.P.

1979-01-01

This is a study of neutron flux and reactivity in several simplified models of a fusion reactor blanket composed of thorium, carbon and a stainless steel structure. The objective is the comparative determination, theoretical and experimental, of values for the conversion of nuclei of Th-232 into fissile U-233 nuclei in such a blanket. Theoretical calculations are carried out using the ANISN (transport equation) and MORSE (Monte Carlo) codes. Experimental values are measured in a stainless steel rack structure allowing simplified blanket models to be mounted around a 14 MeV neutron source. In the first year of work theoretical flux values have been obtained, the necesssary detectors constructed, the rack structure set up, programs worked out for the reactivity calculations, and finally verification methods worked out in conditions similar to those that will prevail. (LL) [fr

Effects of low doses of 14-MeV neutrons on the tensile properties of three binary copper alloys

International Nuclear Information System (INIS)

Heinisch, H.L.; Pintler, J.S.

1986-12-01

Miniature tensile specimens of high purity copper and copper alloyed respectively with five atom percent of Al, Mn, and Ni were irradiated with D-T fusion neutrons in the RTNS-II to fluences up to 1.3 x 10 18 n/cm 2 at 90 0 C. To compare fission and fusion neutron effects, some specimens were also irradiated at the same temperature to similar damage levels in the Omega West Reactor (OWR). Tensile tests were performed at room temperature, and the radiation-induced changes in tensile properties were examined as functions of displacements per atom (dpa). The irradiation-induced strengthening of Cu5%Mn is greater than that of Cu5%Al and Cu5%Ni, which behave about the same. However, all the alloys sustain less irradiation-induced strengthening by 14 MeV neutrons than pure copper, which is in contrast to the reported results of earlier work using hardness measurements. The effects of fission and fusion neutrons on the yield stress of Cu5%Al and Cu5%Ni correlate well on the basis of dpa, but the data for Cu5%Mn suggest that dpa may not be a good correlation parameter for this alloy in this fluence and temperature range

Reactor physics experiments in PURNIMA sub critical facility coupled with 14 MeV neutron source

International Nuclear Information System (INIS)

Kumar, Rajeev; Degweker, S.B.; Patel, Tarun; Bishnoi, Saroj; Adhikari, P.S.

2011-01-01

developed at BARC. Hence it is important to experimentally study the statistical properties of the neutron source for noise experiments. To characterize the statistical properties of the 14 MeV neutron source, neutron counts were collected from DD as well as DT reaction using a time stamping data acquisition card. Data were analyzed to obtain the v/m, auto correlation function and power spectral density (PSD). The study indicates that the source is different from a purely Poisson source. (author)

Measurement of cross sections for the scattering of neutrons in the energy range from 2 MeV to 4 MeV with the 15N(p,n) reaction as neutron source

International Nuclear Information System (INIS)

Poenitz, Erik

2010-01-01

In future nuclear facilities, the materials lead and bismuth can play a more important role than in today's nuclear reactors. Reliable cross section data are required for the design of those facilities. In particular the neutron transport in the lead spallation target of an Accelerator-Driven Subcritical Reactor strongly depends on the inelastic neutron scattering cross sections in the energy region from 0.5 MeV to 6 MeV. In the recent 20 years, elastic and inelastic neutron scattering cross sections were measured with high precision for a variety of elements at the PTB time-of-flight spectrometer. The D(d,n) reaction was primarily used for the production of neutrons. Because of the Q value of the reaction and the available deuteron energies, neutrons in the energy range from 6 MeV to 16 MeV can be produced. For the cross section measurement at lower energies, however, another neutron producing reaction is required. The 15 N(p,n) 15 O reaction was chosen, as it allows the production of monoenergetic neutrons with up to 5.7MeV energy. In this work, the 15 N(p,n) reaction was studied with focus on the suitability as a source for monoenergetic neutrons in scattering experiments. This includes the measurement of differential cross sections for the neutron producing reaction and the choice of optimum target conditions. Differential elastic and inelastic neutron scattering cross sections were measured for lead at four energies in the region from 2 MeV to 4 MeV incident neutron energy using the time-of-flight technique. A lead sample with natural isotopic composition was used. NE213 liquid scintillation detectors with well-known detection efficiencies were used for the detection of the scattered neutrons. Angle-integrated cross sections were determined by a Legendre polynomial expansion using least-squares methods. Additionally, measurements were carried out for isotopically pure 209 Bi and 181 Ta samples at 4 MeV incident neutron energy. Results are compared with other

Energy Dependence of Fission Product Yields from 235U, 238U and 239Pu for Incident Neutron Energies Between 0.5 and 14.8 MeV

Science.gov (United States)

Gooden, Matthew; Bredeweg, Todd; Fowler, Malcolm; Vieira, David; Wilhelmy, Jerry; Tonchev, Anton; Stoyer, Mark; Bhike, Megha; Finch, Sean; Krishichayan, Fnu; Tornow, Werner

2017-09-01

The energy dependence of a number of cumulative fission product yields (FPY) have been measured using quasi- monoenergetic neutron beams for three actinide targets, 235U, 238U and 239Pu, between 0.5 and 14.8 MeV. The FPYs were measured by a combi- nation of fission counting using specially designed dual-fission chambers and -ray counting. Each dual-fission chamber is a back-to-back ioniza- tion chamber encasing an activation target in the center with thin de- posits of the same target isotope in each chamber. This method allows for the direct measurement of the total number of fissions in the activa- tion target with no reference to the fission cross-section, thus reducing uncertainties. γ-ray counting of the activation target was performed on well-shielded HPGe detectors over a period of 2 months post irradiation to properly identify fission products. Reported are absolute cumulative fission product yields for incident neutron energies of 0.5, 1.37, 2.4, 3.6, 4.6 and 14.8 MeV. New data in the second chance fission region of 5.5 - 9 MeV are included. Work performed for the U.S. Department of Energy by Los Alamos National Security, LLC under Contract DE-AC52-06NA25396.

Irradiations of human melanoma cells by 14 MeV neutrons; survival curves interpretation; physical simulation of neutrons interactions in the cellular medium

International Nuclear Information System (INIS)

Bodez, Veronique

2000-01-01

14 MeV neutrons are used to irradiate human melanoma cells in order to study survival curves at low dose and low dose rate. We have simulated with the MCNP code, transport of neutrons through the experimental setup to evaluate the contamination of the primary beam by gamma and electrons, for the feasibility of our experiments. We have shown a rapid decrease of the survival curve in the first cGy followed by a plateau for doses up to 30 cGy; after we observed an exponential decrease. This results are observed for the first time, for neutrons at low dose rate (5 cGy/h). In parallel with this experimental point, we have developed a simulation code which permitted the study of neutrons interactions with the cellular medium for individual cells defined as in our experimental conditions. We show that most of the energy is deposited by protons from neutron interactions with external medium, and by heavy ions for interactions into the cell. On the other hand the code gives a good order of magnitude of the dose rate, compared to the experimental values given by silicon diodes. The first results show that we can, using a theory based on induced repair of cells, give an interpretation of the observed experimental plateau. We can give an estimation of the radial distribution of dose for the tracks of charged ions, we show the possibility of calculate interaction cross sections with cellular organelles. Such a work gives interesting perspectives for the future in radiobiology, radiotherapy or radioprotection. (author) [fr

[Absolute fission cross sections in the 14 MeV energy region]. Progress report, July 1982-June 1983

International Nuclear Information System (INIS)

1983-01-01

Progress is reported on the following studies: thermal neutron absorption cross section of sulfur and the 252 Cf nu bar dilemma, the sigma (H)/sigma (Mn) cross section ratio, the sigma (H)/sigma (B) cross section ratio, 14 MeV neutron cross section measurements, beryllium-based pulsed neutron detector, and testing charged particle transport and Monte Carlo codes

Production of low energy gamma rays by neutron interactions with fluorine for incident neutron energies between 0.1 and 20 MeV

International Nuclear Information System (INIS)

Morgan, G.L.; Dickens, J.K.

1975-06-01

Differential cross sections for the production of low-energy gamma rays (less than 240 keV) by neutron interactions in fluorine have been measured for neutron energies between 0.1 and 20 MeV. The Oak Ridge Electron Linear Accelerator was used as the neutron source. Gamma rays were detected at 92 0 using an intrinsic germanium detector. Incident neutron energies were determined by time-of-flight techniques. Tables are presented for the production cross sections of three gamma rays having energies of 96, 110, and 197 keV. (14 figures, 3 tables) (U.S.)

Fast neutron (14 MeV) attenuation analysis in saturated core samples and its application in well logging

International Nuclear Information System (INIS)

Amin Attarzadeh; Mohammad Kamal Ghassem Al Askari; Tagy Bayat

2009-01-01

To introduce the application of nuclear logging, it is appropriate to provide a motivation for the use of nuclear measurement techniques in well logging. Importance aspects of the geological sciences are for instance grain and porosity structure and porosity volume of the rocks, as well as the transport properties of a fluid in the porous media. Nuclear measurements are, as a rule non-intrusive. Namely, a measurement does not destroy the sample, and it does not interfere with the process to be measured. Also, non- intrusive measurements are often much faster than the radiation methods, and can also be applied in field measurements. A common type of nuclear measurement employs neutron irradiation. It is powerful technique for geophysical analysis. In this research we illustrate the detail of this technique and it's applications to well logging and oil industry. Experiments have been performed to investigate the possibilities of using neutron attenuation measurements to determine water and oil content of rock sample. A beam of 14 MeV neutrons produced by a 150 KV neutron generator was attenuated by different samples and subsequently detected with plastic scintillators NE102 (Fast counter). Each sample was saturated with water and oil. The difference in neutron attenuation between dry and wet samples was compared with the fluid content determined by mass balance of the sample. In this experiment we were able to determine 3% of humidity in standard sample model (SiO 2 ) and estimate porosity in geological samples when saturated with different fluids. (Author)

The total neutron cross sections for 14N and 24Mg

International Nuclear Information System (INIS)

Bommer, J.

This report contains tables of the total neutron cross sections of 14 N and 24 Mg as determined in a recent measurement for neutron energies between 1 and 5.3 MeV. Graphic representations and details on the evaluation of the cross sections are included. (orig.) [de

The analyzing power Asub(y)[(theta) for 12C(n,nsub(0,1))12C betwen 8.9 and] 14.9 MeV neutron energy

International Nuclear Information System (INIS)

Woye, E.; Tornow, W.; Mack, G.; Clegg, T.B.; Wylie, W.

1983-01-01

The analyzing power Asub(#betta#)(theta) for 12 C(n,n) 12 C elastic scattering and for inelastic scattering to the first excited state (Jsup(π) = 2 + , Q = -4.44 MeV) of 12 C was measured in the energy range from 8.9 to 14.9 MeV in 1 MeV steps. A pulsed polarized neutron beam was produced via the 2 H(d vector,n vector) 3 He polarization transfer reaction. Monte Carlo simulations were used to correct the data for finite geometry and multiple scattering effects. The Asub(#betta#) data, together with publsihed cross-section data, were analyzed in the framework of the spherical optical model and in the coupled-channels formalism. A good description of the data has been achieved. (orig.)

Benchmark test of 14-MeV neutron-induced gamma-ray production data in JENDL-3.2 and FENDL/E-1.0 through analysis of the OKTAVIAN experiments

International Nuclear Information System (INIS)

Maekawa, F.; Oyama, F.

1996-01-01

Secondary gamma rays play an important role along with neutrons in influencing nuclear design parameters, such as nuclear heating, radiation dose, and material damage on the plasma-facing components, vacuum vessel, and superconducting magnets, of fusion devices. Because evaluated nuclear data libraries are used in the designs, one must examine the accuracy of secondary gamma-ray data in these libraries through benchmark tests of existing experiments. The validity of the data should be confirmed, or problems with the data should be pointed out through these benchmark tests to ensure the quality of the design. Here, gamma-ray production data of carbon, fluorine, aluminum, silicon, titanium, chromium, manganese, cobalt, copper, niobium, molybdenum, tungsten, and lead in JENDL-3.2 and FENDL/E-1.0 induced by 14-MeV neutrons are tested through benchmark analyses of leakage gamma-ray spectrum measurements conducted at the OKTAVIAN deuterium-tritium neutron source facility. The MCNP transport code is used along with the flagging method for detailed analyses of the spectra. As a result, several moderate problems are pointed out for secondary gamma-ray data of titanium, chromium, manganese, and lead in FENDL/E-1.0. Because no fatal errors are found, however, secondary gamma-ray data for the 13 elements in both libraries are reasonably well validated through these benchmark tests as far as 14-MeV neutron incidence is concerned

Neutron-induced 2.2 MeV background in gamma ray telescopes

International Nuclear Information System (INIS)

Zanrosso, E.M.; Long, J.L.; Zych, A.D.; White, R.S.; Hughes Aircraft Co., Los Angeles, CA)

1985-01-01

Neutron-induced gamma ray production is an important source of background in Compton scatter gamma ray telescopes where organic scintillator material is used. Most important is deuteron formation when atmospheric albedo and locally produced neutrons are thermalized and subsequently absorbed in the hydrogenous material. The resulting 2.2 MeV gamma line essentially represents a continuous isotropic source within the scintillator itself. Interestingly, using a scintillator material with a high hydrogen-to-carbon ratio to minimize the neutron-induced 4.4 MeV carbon line favors the np reaction. The full problem of neutron-induced background in Compton scatter telescopes has been previously discussed. Results are presented of observations with the University of California balloon-borne Compton scatter telescope where the 2.2 MeV induced line emission is prominently seen

Fission Product Yields from {sup 232}Th, {sup 238}U, and {sup 235}U Using 14 MeV Neutrons

Energy Technology Data Exchange (ETDEWEB)

Pierson, B.D., E-mail: bpnuke@umich.edu [Department of Nuclear Engineering Radiological Sciences, University of Michigan, 2355 Bonisteel Blvd., Ann Arbor, MI 48109 (United States); Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352 (United States); Greenwood, L.R. [Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352 (United States); Flaska, M. [Department of Mechanical and Nuclear Engineering, Pennsylvania State University, 227 Reber Bldg., University Park, PA 16802 (United States); Pozzi, S.A. [Department of Nuclear Engineering Radiological Sciences, University of Michigan, 2355 Bonisteel Blvd., Ann Arbor, MI 48109 (United States)

2017-01-15

Neutron-induced fission yield studies using deuterium-tritium fusion-produced 14 MeV neutrons have not yet directly measured fission yields from fission products with half-lives on the order of seconds (far from the line of nuclear stability). Fundamental data of this nature are important for improving and validating the current models of the nuclear fission process. Cyclic neutron activation analysis (CNAA) was performed on three actinide targets–thorium-oxide, depleted uranium metal, and highly enriched uranium metal–at the University of Michigan's Neutron Science Laboratory (UM-NSL) using a pneumatic system and Thermo-Scientific D711 accelerator-based fusion neutron generator. This was done to measure the fission yields of short-lived fission products and to examine the differences between the delayed fission product signatures of the three actinides. The measured data were compared against previously published results for {sup 89}Kr, −90, and −92 and {sup 138}Xe, −139, and −140. The average percent deviation of the measured values from the Evaluated Nuclear Data Files VII.1 (ENDF/B-VII.1) for thorium, depleted-uranium, and highly-enriched uranium were −10.2%, 4.5%, and −12.9%, respectively. In addition to the measurements of the six known fission products, 23 new fission yield measurements from {sup 84}As to {sup 146}La are presented.

Near term, low cost, 14 MeV fusion neutron irradiation facility for testing the viability of fusion structural materials

Energy Technology Data Exchange (ETDEWEB)

Kulcinski, Gerald L., E-mail: glkulcin@wisc.edu [University of Wisconsin-Madison, Madison, WI (United States); Radel, Ross F. [Phoenix Nuclear Labs LLC, Monona, WI (United States); Davis, Andrew [University of Wisconsin-Madison, Madison, WI (United States)

2016-11-01

For over 50 years, engineers have been looking for an irradiation facility that can provide a fusion reactor appropriate neutron spectrum over a significant volume to test fusion reactor materials that is relatively inexpensive and can be built in a minimum of time. The 14 MeV neutron irradiation facility described here can nearly exactly duplicate the neutron spectrum typical of a DT fusion reactor first wall at damage rates of ≈4 displacements per atom and 40 appm He generated over a 2 l volume per full power year of operation. The projected cost of this multi-beam facility is estimated at ≈$20 million and it can be built in <4 years. A single-beam prototype, funded by the U.S. Department of Energy, is already being built to produce medical isotopes. The neutrons are produced by a 300 keV deuterium beam accelerated into 4 kPa (30 Torr) tritium target. The total tritium inventory is <2 g and <0.1 g of T{sub 2} is consumed per year. The core technology proposed has already been fully demonstrated, and no new plasma physics or materials innovations will be required for the test facility to become operational.

Transmission line matching simulation for 350 MHz RF driver for 400 KeV (deuterium) RFQ based 14 MeV neutron source

International Nuclear Information System (INIS)

Sharma, Sonal; Pande, Manjiri; Handu, V.K.

2009-01-01

A 60 KW, 350 MHz tetrode based high power RF system is being developed for 400 KeV RFQ based 14 MeV neutron generator in Bhabha Atomic Research Centre to study physics of coupled neutron sources and subcritical assembly. This RF system requires a 2.5 kW RF driver which is being designed by using tetrode TH-393. At such high frequency i.e. 350 MHz, lumped components are not practically useful due to radiation losses. Therefore, techniques such as coaxial line with stub tuning are preferred, which minimizes these losses. Simulation of two such stub tuning based matched coaxial lines at the input and output of the tube has been done by using CST studio. CST STUDIO is a special tool for the 3D EM simulation of high frequency components

Compilation and evaluation of 14-MeV neutron-activation cross sections for nuclear technology applications. Set I

International Nuclear Information System (INIS)

Evain, B.P.; Smith, D.L.; Lucchese, P.

1985-04-01

Available 14-MeV experimental neutron activation cross sections are compiled and evaluated for the following reactions of interest for nuclear-energy technology applications: 27 Al(n,p) 27 Mg, Si(n,X) 28 Al, Ti(n,X) 46 Sc, Ti(n,X) 47 Sc, Ti(n,X) 48 Sc, 51 V(n,p) 51 Ti, 51 V(n,α) 48 Sc, Cr(n,X) 52 V, 55 Mn(n,α) 52 V, 55 Mn(n,2n) 54 Mn, Fe(n,X) 54 Mn, 54 Fe(n,α) 51 Cr, 59 Co(n,p) 59 Fe, 59 Co(n,α) 56 Mn, 59 Co(n,2n) 58 Co, 65 Cu(n,p) 65 Ni, Zn(n,X) 64 Cu, 64 Zn(n,2n) 63 Zn, 113 In(n,n')/sup 113m/In, 115 In(n,n') /sup 115m/In. The compiled values are listed and plotted for reference without adjustments. From these collected results those values for which adequate supplementary information on nuclear constants, standards and experimental errors is provided are selected for use in reaction-by-reaction evaluations. These data are adjusted as needed to account for recent revisions in the nuclear constants and cross section standards. The adjusted results are subsequently transformed to equivalent cross sections at 14.7 MeV for the evaluation process. The evaluations are performed utilizing a least-squares method which considers correlations between the experimental data. 440 refs., 41 figs., 46 tabs

Container Inspection Utilizing 14 MeV Neutrons

Science.gov (United States)

Valkovic, Vladivoj; Sudac, Davorin; Nad, Karlo; Obhodas, Jasmina

2016-06-01

A proposal for an autonomous and flexible ship container inspection system is presented. This could be accomplished by the incorporation of an inspection system on various container transportation devices (straddle carriers, yard gentry cranes, automated guided vehicles, trailers). The configuration is terminal specific and it should be defined by the container terminal operator. This enables that no part of the port operational area is used for inspection. The inspection scenario includes container transfer from ship to transportation device with the inspection unit mounted on it. The inspection is performed during actual container movement to the container location. A neutron generator without associated alpha particle detection is used. This allows the use of higher neutron intensities (5 × 109 - 1010 n/s in 4π). The inspected container is stationary in the “inspection position” on the transportation device while the “inspection unit” moves along its side. The following analytical methods will be used simultaneously: neutron radiography, X-ray radiography, neutron activation analysis, (n, γ) and (n,n'γ) reactions, neutron absorption. and scattering, X-ray backscattering. The neutron techniques will utilize “smart collimators” for neutrons and gamma rays, both emitted and detected. The inspected voxel is defined by the intersection of the neutron generator and the detectors solid angles. The container inspection protocol is based on identification of discrepancies between the cargo manifest, elemental “fingerprint” and radiography profiles. In addition, the information on container weight is obtained during the container transport and screening by measuring of density of material in the container.

Cross section measurements for gallium in the neutron energy range of 13.5 to 14.8 MeV

Energy Technology Data Exchange (ETDEWEB)

Luo, J. [Hexi Univ., Zhangye (China). School of Physics and Electromechanical Engineering; Liu, R.; Jiang, L. [Chinese Academy of Engineering Physics, Mianyang (China). Inst. of Nuclear Physics and Chemistry

2012-07-01

Cross sections for (n, 2n), (n, p) and (n, n'{alpha}) reactions have been measured on gallium isotopes at the neutron energies of 13.5-14.8 MeV using the activation technique. The monoenergetic neutron beam was produced via the {sup 3}H(d, n){sup 4}He reaction. The neutron fluences were determined using the monitor reaction {sup 27}Al(n, {alpha}){sup 24}Na. The activities induced in the reaction products were measured using high-resolution gamma-ray spectrometry. Data are reported for the following reactions: {sup 69}Ga(n, 2n){sup 68}Ga, {sup 71}Ga(n, 2n) {sup 70}Ga, {sup 69}Ga(n, p){sup 69m}Zn, {sup 71}Ga(n, p){sup 71m}Zn and {sup 71} Ga(n, n'{alpha}){sup 67}Cu. Nuclear model calculations using the code HFTT, which employs the Hauser-Feshbach (statistical model) and exciton model (precompound effects) formalisms, were undertaken to describe the formation of the reaction products. Results are discussed and compared with some corresponding values found in the literature, with some established systematics and with the evaluated data given in ENDF/B-VII.0, CENDL-3.1 and JENDL-4.0. (orig.)

Differential α-production cross sections of iron and nickel for 4.3 to 14.1 MeV Neutrons

International Nuclear Information System (INIS)

Baba, Mamoru; Ito, Nobuo; Matsuyama, Isamu

1994-01-01

The cross section data for neutron-induced α-production are of prime importance in the evaluation of the radiation damage and nuclear heating in fusion and fast reactors. For the evaluation, energy and angular doubly differential cross sections are also required to calculate primary knock-on atom spectra. However, the experimental (n, xα) data are few and discrepant, therefore, the new experimental data are required urgently to improve the accuracy of the (n, xα) cross section data. The authors have measured the double differential (n, xα) cross sections of Fe and Ni in the neutron energy range of 4.3-14.1 MeV using a specially developed gridded ionization chamber. The present work was undertaken as a part of IAEA Coordinated Research Program for neutron-induced He production cross sections. The gridded ionization chamber and the experimental method were reported previously. Three-signals from the common cathode and two anodes were accumulated as two sets of two-dimensional data. The experimental two-dimensional data for the anode and cathode signals were transformed into the double differential cross sections. The results of the double differential cross sections, angular distributions, angle-integrated spectra in the center of mass system and total α-production cross sections are shown. (K.I.)

Application of multi-step direct reaction theory to 14 MeV neutron reaction, 3 (n,. cap alpha. )

Energy Technology Data Exchange (ETDEWEB)

Kumabe, I.; Matoba, M.; Fukuda, K. [Kyushu Univ., Fukuoka (Japan). Faculty of Engineering; Ikegami, H.; Muraoka, M [eds.

1980-01-01

Multi-step direct-reaction theory proposed by Tamura et al. has been applied to continuous spectra of the 14 MeV (n, ..cap alpha..) reaction with some modifications. Calculated results reproduce well the experimental energy and angular distributions of the 14 MeV (n, ..cap alpha..) reactions.

Cross sections for the 14N(n,p0), (n,α0), and (n,α1) reactions from 0.5 to 15 MeV

International Nuclear Information System (INIS)

Morgan, G.L.

1978-09-01

Cross sections were measured for the 14 N(n,p 0 ) reaction from 0.5 to 7.0 MeV and for the (n,α 0 ) and (n,α 1 ) reactions from 1 to 15 MeV and 4 to 15 MeV, respectively. The data were obtained using a gaseous scintillator containing N 2 and Xe mixtures. A linac was used as a pulsed, white neutron source with a 29-m fight path. The results of the measurement are compared to the current evaluated file for nitrogen; agreement is good for neutron energies below 8 MeV, but the measurement is substantially higher than the evaluation for neutron energies near 10 MeV

Gamma ray production cross sections for the interactions of 14.9 MeV neutrons with C, Al, V, Fe and Nb at 90 deg

International Nuclear Information System (INIS)

Zhou Hongyu; Tang Lin; Yan Yiming

1986-11-01

Discrete γ-ray spectra and production cross sections for the interactions of 14.9 MeV neutrons with C, Al, V, Fe and Nb targets have been measured at 90 deg. using a 110.7cm 3 Ge(Li) detector. A single γ-ray peak was measured for C. For Al 34 γ lines, for Fe 41 γ lines, for V 61 γ lines and for Nb 79 γ lines were measured

Measurements of the {sup 235}U(n,f) cross section in the 3 to 30 MeV neutron energy region

Energy Technology Data Exchange (ETDEWEB)

Carlson, A.D.; Wasson, O.A. [National Institute of Standards and Technology, Gaithersburg, MD (United States); Lisowski, P.W. [Los Alamos National Lab., NM (United States)] [and others

1991-12-31

To improve the accuracy of the {sup 235}U(n,f) cross section, measurements have been made of this standard cross section at the target 4 facility at Los Alamos National Laboratory (LANL). The data were obtained at the 20-meter flight path of that facility. The fission reaction rate was determined with a fast parallel plate ionization chamber and the neutron fluence was measured with an annular proton recoil telescope. The measurements provide the shape of the {sup 235}U(n,f) cross section relative to the hydrogen scattering cross section for neutron energies from about 3 to 30 MeV neutron energy. The data have been normalized to the very accurately known value near 14 MeV. The results are in good agreement with the ENDF/B-VI evaluation up to about 15 MeV neutron energy. Above this energy differences as large as 5% are observed.

Measurement of cross sections producing short-lived nuclei by 14MeV neutron. Cd, Sn, Te, Nd, Gd, Re

Energy Technology Data Exchange (ETDEWEB)

Sakane, H.; Yamamoto, H.; Kawade, K. [Nagoya Univ. (Japan); Iida, T.; Takahashi, A.

1998-03-01

Nine neutron activation cross sections producing the nuclei with half-lives between 25sec and 22min were measured at energy range between 13.4 and 14.9 MeV by activation method. The (n,p) and (n,{alpha}) reaction cross sections were measured for the isotopes of {sup 110}Cd, {sup 112}Sn, {sup 122}Te, {sup 130}Te and {sup 185}Re and those of {sup 130}Te, {sup 148}Nd and {sup 158}Gd, respectively. The present results were compared with our systematics proposed on the basis of 58 cross section data of (n,p) and 33 data of (n,{alpha}) reaction. Good agreements have been seen between them. (author)

Neutron-photon multigroup cross sections for neutron energies less than or equal to400 MeV. Revision 1

International Nuclear Information System (INIS)

Alsmiller, R.G. Jr.; Barnes, J.M.; Drischler, J.D.

1986-01-01

For a variety of applications, e.g., accelerator shielding design, neutrons in radiotherapy, radiation damage studies, etc., it is necessary to carry out transport calculations involving medium-energy (greater than or equal to20 MeV) neutrons. A previous paper described neutron-photon multigroup cross sections in the ANISN format for neutrons from thermal to 400 MeV. In the present paper the cross-section data presented previously have been revised to make them agree with available experimental data. 7 refs., 1 fig

Measurements of activation cross-sections for the 101Ru(n,p)101Tc reaction for neutrons with energies between 13 and 15 MeV

International Nuclear Information System (INIS)

Junhua Luo; Peking University, Beijing; Jiuning Han; Suhong Ge; Zhenlai Liu; Guihua Sun; Rong Liu; Li Jiang

2013-01-01

In this study, activation cross-sections were measured for the 101 Ru(n,p) 101 Tc reaction at three different neutron energies from 13.5 to 14.8 MeV. The fast neutrons were produced via the 3 H(d,n) 4 He reaction on K-400 neutron generator. Induced gamma activities were measured by a high-resolution gamma-ray spectrometer with high-purity germanium detector. Measurements were corrected for gamma-ray attenuations, random coincidence (pile-up), dead time and fluctuation of neutron flux. The data for 101 Ru(n,p) 101 Tc reaction cross-sections are reported to be 15.7 ± 2.0, 18.4 ± 2.7 and 22.0 ± 2.4 mb at 13.5 ± 0.2, 14.1 ± 0.2, and 14.8 ± 0.2 MeV incident neutron energies, respectively. Results were compared with the previous works. (author)

Determination of protein content in some foodstaffs using 14 MeV NAA

International Nuclear Information System (INIS)

Abdel Samei, M.B.; Elshafie, M.A.; Hanna, M.; Csikai, J.; Juhasz, M.

1986-01-01

The protein content of meals of various seeds (rice, lupine, sorghum, pumpkin, linseed, water melon, tomato) collected from Egypt and the USA was determined by 14 MeV neutron activation analysis via sup(14)N(n,2n)sup(13)N reaction. Non-conventional sources like tea and coffee residues are also investigated. The concentrations of trace elements determined by the x-ray fluorescence technique show definite differences even for a given type of seed produced in different geographical regions. (author)

Measurement of neutron yield by 62 MeV proton beam on a thick beryllium target

Energy Technology Data Exchange (ETDEWEB)

Osipenko, M., E-mail: osipenko@ge.infn.it [INFN, sezione di Genova, 16146 Genova (Italy); Ripani, M. [INFN, sezione di Genova, 16146 Genova (Italy); Alba, R. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Ricco, G. [INFN, sezione di Genova, 16146 Genova (Italy); Schillaci, M. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Barbagallo, M. [INFN, sezione di Bari, 70126 Bari (Italy); Boccaccio, P. [INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro (Italy); Celentano, A. [Dipartimento di Fisica dell' Università di Genova, 16146 Genova (Italy); Colonna, N. [INFN, sezione di Bari, 70126 Bari (Italy); Cosentino, L.; Del Zoppo, A.; Di Pietro, A. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Esposito, J. [INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro (Italy); Figuera, P.; Finocchiaro, P. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Kostyukov, A. [Moscow State University, Moscow 119992 (Russian Federation); Maiolino, C.; Santonocito, D.; Scuderi, V. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Viberti, C.M. [Dipartimento di Fisica dell' Università di Genova, 16146 Genova (Italy)

2013-09-21

The design of a low-power prototype of neutron amplifier recently proposed within the INFN-E project indicated the need for more accurate data on the neutron yield produced by a proton beam with energy of about 70 MeV impinging on a thick beryllium target. Such measurement was performed at the LNS superconducting cyclotron, covering a wide angular range from 0° to 150° and a complete neutron energy interval from thermal to beam energy. Neutrons with energy above 0.5 MeV were measured by liquid scintillators exploiting their time of flight to determine the kinetic energy. For lower energy neutrons, down to thermal energy, a {sup 3}He detector was used. The obtained data are in good agreement with previous measurements at 0° using 66 MeV proton beam, covering neutron energies >10MeV, as well as with measurements at few selected angles using protons of 46, 55 and 113 MeV energy. The present results extend the neutron yield data in the 60–70 MeV beam energy range. A comparison of measured yields to MCNP, FLUKA and Geant4 Monte Carlo simulations was performed.

Energy Dependence of Fission Product Yields from 235U, 238U and 239Pu for Incident Neutron Energies Between 0.5 and 14.8 MeV

Science.gov (United States)

Gooden, M. E.; Arnold, C. W.; Becker, J. A.; Bhatia, C.; Bhike, M.; Bond, E. M.; Bredeweg, T. A.; Fallin, B.; Fowler, M. M.; Howell, C. R.; Kelley, J. H.; Krishichayan; Macri, R.; Rusev, G.; Ryan, C.; Sheets, S. A.; Stoyer, M. A.; Tonchev, A. P.; Tornow, W.; Vieira, D. J.; Wilhelmy, J. B.

2016-01-01

Fission Product Yields (FPY) have historically been one of the most observable features of the fission process. They are known to have strong variations that are dependent on the fissioning species, the excitation energy, and the angular momentum of the compound system. However, consistent and systematic studies of the variation of these FPY with energy have proved challenging. This is caused primarily by the nature of the experiments that have traditionally relied on radiochemical procedures to isolate specific fission products. Although radiochemical procedures exist that can isolate all products, each element presents specific challenges and introduces varying degrees of systematic errors that can make inter-comparison of FPY uncertain. Although of high importance in fields such as nuclear forensics and Stockpile Stewardship, accurate information about the energy dependence of neutron induced FPY are sparse, due primarily to the lack of suitable monoenergetic neutron sources. There is a clear need for improved data, and to address this issue, a collaboration was formed between Los Alamos National Laboratory (LANL), Lawrence Livermore National Laboratory (LLNL) and the Triangle Universities Nuclear Laboratory (TUNL) to measure the energy dependence of FPY for 235U, 238U and 239Pu. The measurements have been performed at TUNL, using a 10 MV Tandem Van de Graaff accelerator to produce monoenergetic neutrons at energies between 0.6 MeV to 14.8 MeV through a variety of reactions. The measurements have utilized a dual-fission chamber, with thin (10-100 μg/cm2) reference foils of similar material to a thick (100-400 mg) activation target held in the center between the chambers. This method allows for the accurate determination of the number of fissions that occurred in the thick target without requiring knowledge of the fission cross section or neutron fluence on target. Following activation, the thick target was removed from the dual-fission chamber and gamma

Analyzing power Asub(y)((theta) for /sup 12/C(n,nsub(0,1))/sup 12/C betwen 8. 9 and) 14. 9 MeV neutron energy

Energy Technology Data Exchange (ETDEWEB)

Woye, E.; Tornow, W.; Mack, G. (Tuebingen Univ. (Germany, F.R.). Physikalisches Inst.); Floyd, C.E.; Guss, P.P.; Murphy, K.; Byrd, R.C.; Wender, S.A.; Walter, R.L. (Duke Univ., Durham, NC (USA). Dept. of Physics; Triangle Universities Nuclear Lab., Durham, NC (USA))

1983-02-01

The analyzing power Asub(..gamma..)(theta) for /sup 12/C(n,n)/sup 12/C elastic scattering and for inelastic scattering to the first excited state (Jsup(..pi..) = 2/sup +/, Q = -4.44 MeV) of /sup 12/C was measured in the energy range from 8.9 to 14.9 MeV in 1 MeV steps. A pulsed polarized neutron beam was produced via the /sup 2/H(d vector,n vector)/sup 3/He polarization transfer reaction. Monte Carlo simulations were used to correct the data for finite geometry and multiple scattering effects. The Asub(..gamma..) data, together with publsihed cross-section data, were analyzed in the framework of the spherical optical model and in the coupled-channels formalism. A good description of the data has been achieved.

Effects of single and split doses of cobalt-60 gamma rays and 14 MeV neutrons on mouse stem cell spermatogonia.

Science.gov (United States)

Hacker-Klom, U B; Köhnlein, W; Göhde, W

2000-12-01

The long-term effects of ionizing radiation on male gonads may be the result of damage to spermatogonial stem cells. Doses of 10 cGy to 15 Gy (60)Co gamma rays or 10 cGy to 7 Gy 14 MeV neutrons were given to NMRI mice as single or split doses separated by a 24-h interval. The ratios of haploid spermatids/2c cells and the coefficients of variation of DNA histogram peaks as measures of both the cytocidal and the clastogenic actions of radiation were analyzed by DNA flow cytometry after DAPI staining. The coefficient of variation is not only a statistical examination of the data but is also used here as a measure of residual damage to DNA (i.e. a biological dosimeter). Testicular histology was examined in parallel. At 70 days after irradiation, the relative biological effectiveness for neutrons at 50% survival of spermatogonial stem cells was 3.6 for single doses and 2.8 for split doses. The average coefficient of variation of unirradiated controls of elongated spermatids was doubled when stem cells were irradiated with single doses of approximately 14 Gy (60)Co gamma rays or 3 Gy neutrons and observed 70 days later. Split doses of (60)Co gamma rays were more effective than single doses, doubling DNA dispersion at 7 Gy. No fractionation effect was found with neutrons with coefficients of variation.

Elastic Neutron Scattering at 96 MeV from {sup 12}C and {sup 208}Pb

Energy Technology Data Exchange (ETDEWEB)

Klug, J.; Blomgren, J.; Atac, A. [and others

2003-04-01

A facility for detection of scattered neutrons in the energy interval 50-130 MeV, SCANDAL (SCAttered Nucleon Detection AssembLy), has recently been installed at the 20-180 MeV neutron beam line of the The Svedberg Laboratory, Uppsala. Elastic neutron scattering from {sup 12}C and {sup 208}Pb has been studied at 96 MeV in the 10-70 deg interval. The achieved energy resolution, 3.7 MeV, is about an order of magnitude better than for any previous experiment above 65 MeV incident energy. The present experiment represents the highest neutron energy where the ground state has been resolved from the first excited state in neutron scattering. A novel method for normalization of the absolute scale of the cross section has been used. The estimated uncertainty, 3 %, is unprecedented for a neutron-induced differential cross section measurement on a nuclear target. The results are compared with modern optical model predictions, based on phenomenology or microscopic nuclear theory.

Measurement of 167Er(n,p)167Ho reaction at 13.5 and 14.8 MeV

International Nuclear Information System (INIS)

Luo, Junhua; Liu, Jun; Han, Jiuning; Jiang, Li; Liu, Rong; Ge, Suhong; Liu, Zhenlai

2013-01-01

We have measured the 167 Er(n,p) 167 Ho cross-sections at two different neutron energies 13.5 and 14.8 MeV. Measurements were performed at Pd-300 neutron generator of Chinese Academy of Engineering Physics (CAEP) with monoenergetic neutrons produced via the 3 H(d,n) 4 He reaction using a tritium–titanium (T–Ti) target. Induced gamma activities were measured by a high-resolution gamma-ray spectrometer with high-purity germanium (HPGe) detector. The data for 167 Er(n,p) 167 Ho reaction cross-sections are reported to be 2.2±0.6 and 2.8±1.4 mb at 13.5±0.2 and 14.8±0.2 MeV incident neutron energies, respectively. The cross sections were also estimated with the TALYS-1.4 nuclear model code and compared with experimental data found in the literature, and with the comprehensive evaluation data in ENDF/B-VII.1 and JEFF-3.1/A libraries. - Highlights: • D–T neutron source was used to measure cross sections using activation method. • 27 Al(n,α) 24 Na was used as the monitor for the measurement. • The cross sections for the 167 Er(n,p) 167 Ho reactions have been measured. • Contribution of the interfering reaction 170 Er(n,α) 167 Dy was subtracted. • The results were compared with previous data and with evaluation data

Detection of 14 MeV neutrons in high temperature environment up to 500 deg. C using 4H-SiC based diode detector

Energy Technology Data Exchange (ETDEWEB)

Szalkai, D.; Klix, A. [KIT- Karlsruhe Institute of Technology, Institute of Neutron Physics and Reactor Technology Karlsruhe 76344 (Germany); Ferone, R.; Issa, F.; Ottaviani, L.; Vervisch, V. [IM2NP, UMR CNRS 7334, Aix-Marseille University, Case 231 -13397 Marseille Cedex 20 (France); Gehre, D. [Inst. for Nucl.- and Particle-Phys., Dresden University of Technology, Dresden 01069 (Germany); Lyoussi, A. [CEA, DEN, Departement d' Etudes des Reacteurs, Service de Physique Experimentale, Laboratoire Dosimetrie Capteurs Instrumentation, 13108 Saint-Paul-lez-Durance (France)

2015-07-01

In reactor technology and industrial applications detection of fast and thermal neutrons plays a crucial role in getting relevant information about the reactor environment and neutron yield. The inevitable elevated temperatures make neutron yield measurements problematic. Out of the currently available semiconductors 4H-SiC seems to be the most suitable neutron detector material under extreme conditions due to its high heat and radiation resistance, large band-gap and lower cost of production than in case of competing diamond detectors. In the framework of the European I-Smart project, optimal {sup 4}H-SiC diode geometries were developed for high temperature neutron detection and have been tested with 14 MeV fast neutrons supplied by a deuterium-tritium neutron generator with an average neutron flux of 10{sup 10}-10{sup 11} n/(s*cm{sup 2}) at Neutron Laboratory of the Technical University of Dresden in Germany from room temperatures up to several hundred degrees Celsius. Based on the results of the diode measurements, detector geometries appear to play a crucial role for high temperature measurements up to 500 deg. C. Experimental set-ups using SiC detectors were constructed to simulate operation in the harsh environmental conditions found in the tritium breeding blanket of the ITER fusion reactor, which is planned to be the location of neutron flux characterization measurements in the near future. (authors)

Determination of phosphorus and calcium in biological samples by activation with 14 MeV neutrons

International Nuclear Information System (INIS)

Berretta, Jose Roberto

1995-01-01

Analytical methods for phosphorus and calcium in biological samples by means of activation with 14 MeV neutrons, using the Van de Graaff accelerator from the Instituto de Pesquisas Energeticas e Nucleares, SP, Brazil are developed. For phosphorus analysis, powder samples were pressed into pellets, weighed and transferred to polyethylene plastic envelopes. The pellets with cadmium shielding were irradiated under a fast neutron flux for 5 to 10 minutes, and further counted in a HPGe detector for 5 minutes. Calcium analysis was performed by cyclic irradiation. Samples were irradiated for 10 minutes. After a decay time of 2 minutes, gamma counting was performed for 10 minutes. After a decay time of 2 minutes, a new irradiation ws made. The irradiation cycle was repeated 5 times and the counting spectrum obtained in each cycle was accumulated in the multi channel analyser. The variation of the neutron flux was followed by using a BF 3 detector calibrated with and aluminium monitor. By means of the gamma spectrum and the neutron counting of the BF 3 detector it was possible to estimate phosphorus and calcium concentrations in the sample analyzed. The methods were checked in the reference samples from the International Atomic Energy Agency and in commercial samples of powder milk, fertilizer and animal bone. Phosphorus contents in bone (A3/74) and milk (A-11) reference materials were (15.6 +- 1.8%) and (0.9 +- 0.1)%, respectively. These values are in good agreement to the certified values (15.5 +- 0.5)% and (0.910 +- 0.102)%, respectively. Calcium analysis carried out in bone (A3/74) presented a value of (31.8+-4.1)% and the certified value was of (31.3 +- 0.3)%. Detection limits for phosphorus and calcium were determined in different analyzed samples. The agreement of the results obtained with the certified values confirmed the suitability of the methods for phosphorus and calcium analysis. The methods are fast and laborious chemical procedures are not required. (author)

Secondary standards (non-activation) for neutron data measurements above 20 MeV

International Nuclear Information System (INIS)

Haight, R.C.

1991-01-01

In addition to H(n,p) scattering and 235,238 U(n,f) reactions, secondary standards for neutron flux determination may be useful for neutron energies above 20 MeV. For experiments where gamma rays are detected, reference gamma-ray production cross sections are relevant. For neutron-induced charged particle production, standard (n,p) and (n,alpha) cross sections would be helpful. Total cross section standards would serve to check the accuracy of these measurements. These secondary standards are desirable because they can be used with the same detector systems employed in measuring the quantities of interest. Uncertainties due to detector efficiency, geometrical effects, timing and length of flight paths can therefore be significantly reduced. Several secondary standards that do not depend on activation techniques are proposed. 14 refs

Calculation of neutron cross sections on iron up to 40 MeV

International Nuclear Information System (INIS)

Arthur, E.D.; Young, P.G.

1980-01-01

The development of high energy d + Li neutron sources for fusion materials radiation damage studies will require neutron cross sections up to 40 MeV. Experimental data above 15 MeV are generally sparse or nonexistent, and reliance must be placed upon nuclear-model calculations to produce the needed cross sections. To satisfy such requirements for the Fusion Materials Irradiation Test Facility (FMIT), neutron cross sections have been calculated for 54 56 Fe between 3 and 40 MeV. These results were joined to the existing ENDF/B-V evaluation below 3 MeV. In this energy range, most neutron reactions can be described using the Hauser-Feshbach statistical model with corrections for preequilibrium and direct-reaction effects. To properly use these models to obtain realistic cross sections, emphasis must be placed upon the determination of suitable input parameters (optical model sets, gamma-ray strength functions, level densities) valid over the energy range of the calculation. To do this, several types of independent data were used to arrive at consistent parameter sets as described

Cross-section calculations for neutron-induced reactions up to 50 MeV

International Nuclear Information System (INIS)

Yamamuro, Nobuhiro.

1996-01-01

In the field of accelerator development, medium-energy reaction cross-section data for structural materials of accelerator and shielding components are required, especially for radiation protection purposes. For a d + Li stripping reaction neutron source used in materials research, neutron reaction cross sections up to 50 MeV are necessary for the design study of neutron irradiation facilities. The current version of SINCROS-II is able to calculate neutron and proton-induced reaction cross sections up to ∼ 50 MeV with some modifications and extensions of the cross-section calculation code. The production of isotopes when structural materials and other materials are bombarded with neutrons or protons is calculated using a revised code in the SINCROS-II system. The parameters used in the cross-section calculations are mainly examined with proton-induced reactions because the experimental data for neutrons above 20 MeV are rare. The status of medium mass nuclide evaluations for aluminum, silicon, chromium, manganese, and copper is presented. These data are useful to estimate the radiation and transmutation of nuclei in the materials

Neutron scattering differential cross sections of carbon and bismuth at 37 MeV

International Nuclear Information System (INIS)

Zhou Zuying; Tang Hongqing; Qi Bujia; Zhou Chenwei; Du Yanfeng; Xia Haihong; Walter, R.L.; Tornow, W.; Howell, C.; Braun, R.; Roper, C.; Chen Zemin; Chen Zhengpeng; Chen Yingtang

1997-01-01

Elastic differential cross sections of 37 MeV neutrons scattered from carbon and bismuth were measured in the angular range 11 to 160 degrees by means of the multi-detector TOF facility. The 37 MeV neutrons were produced via the T(d,n) 4 He reaction in a tritium gas target. The pulsed 20 MeV deuteron beam was provided by the HI-13 tandem accelerator. The angular distribution of scattered neutrons from carbon and bismuth were measured in the angular range 11 degree to 145 degree and 11 degree to 160 degree respectively in steps of about 3 degree

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

International Nuclear Information System (INIS)

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

1985-12-01

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

Neutron-induced fission of uranium isotopes up to 100 MeV

International Nuclear Information System (INIS)

Lestone, J.P.; Gavron, A.

1994-01-01

The statistical-model description of the neutron-induced fission of U isotopes has been developed using densities of intrinsic states and spin cutoff parameters obtained directly from appropriate Nilsson model single-particle levels. The first-chance fission cross sections are reproduced well when the rotational contributions to the nuclear level densities are taken into account. In order to fit the U(n,f) cross sections above the threshold of second-chance fission, we must: (1) assume that the triaxial level-density enhancement is washed out at an excitation energy of approximately 7 MeV above the triaxial barriers with a width of approximately 1 MeV, implying a γ deformation for the first barriers where 10<γ<20 degree, and (2) include preequilibrium particle emission in the calculations. Above an incoming-neutron kinetic energy of approximately 17 MeV, our statistical model U(n,f) of cross sections increasingly overestimates the experimental data. This is not surprising since, at these high energies, little data exist on the scattering of neutrons to help guide the choice of optical-model parameters. A satisfactory reproduction of all of the available U(n,f) cross sections above 17 MeV is obtained by scaling our calculated compound-nucleus formation cross sections. This scaling factor falls from 1.0 at 17 MeV to 0.82 at 100 MeV

Neutron-induced charged-particle emission studies below 100 MeV at WNR

Energy Technology Data Exchange (ETDEWEB)

Haight, R.C.; Lee, T.M.; Sterbenz, S.M. [and others

1994-07-01

Charged-particles produced by neutron bombardment of selected targets with Z=5 through 53 have been studied for neutron energies from 1 MeV to about 100 MeV using the spallation neutron source at WNR/LAMPF. Particle detection with energy measurement and particle identification is accomplished by two-element {Delta}E-E counters, three-element {Delta}E{sub l}-{Delta}E{sub 2}-E counters or with pulse-shape discrimination using scintillators directly in the neutron beam. The experimental techniques for these measurements are described and comparisons made among the different approaches. This presentation introduces five papers contributed to this conference.

Neutron-induced charged-particle emission studies below 100 MeV at WNR

International Nuclear Information System (INIS)

Haight, R.C.; Lee, T.M.; Sterbenz, S.M.

1994-01-01

Charged-particles produced by neutron bombardment of selected targets with Z=5 through 53 have been studied for neutron energies from 1 MeV to about 100 MeV using the spallation neutron source at WNR/LAMPF. Particle detection with energy measurement and particle identification is accomplished by two-element ΔE-E counters, three-element ΔE l -ΔE 2 -E counters or with pulse-shape discrimination using scintillators directly in the neutron beam. The experimental techniques for these measurements are described and comparisons made among the different approaches. This presentation introduces five papers contributed to this conference

Little Boy neutron spectrum below 3 MeV

International Nuclear Information System (INIS)

Evans, A.E.; Bennett, E.F.; Yule, T.J.

1984-01-01

The leakage neutron spectrum from the Little Boy replica has been measured from 12 keV to 3 MeV using a high-resolution 3 He ionization chamber, and from 1 keV to 3 MeV using proton-recoil proportional counters. The 3 He-spectrometer measurements were made at distances of 0.75 and 2.0 m from the active center and at angles of 0 0 , 45 0 , and 90 0 with respect to the axis of the assembly. Proton-recoil measurments were made at 90 0 to the assembly axis at distances of 0.75 and 2.0 m, with a shielded measurement made at 2.0 m to estimate background due to scattering. The 3 He spectrometer was calibrated at Los Alamos using monoenergetic 7 Li(p,n) 7 Be neutrons to generate a family of response functions. The proton-recoil counters were calibrated at Argonne by studying the capture of thermal neutrons by nitrogen in the counters, by observation of the 24-keV neutron resonance in iron, and by relating to the known hydrogen content of the counters. The neutron spectrum from Little Boy was found to be highly structured, with peaks corresponding to minima in the iron total neutron cross section. In particular, influence of the 24-keV iron window was evident in both sets of spectra. The measurements provide information for dosimetry calculations and also a valuable intercomparison of neutron spectrometry using the two different detector types. Spectra measured with both detectors are in essential agreement. 8 references, 7 figures, 2 tables

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

International Nuclear Information System (INIS)

Miyahara, A.; Coensgen, F.H.

1988-06-01

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

Comprehensive Measurement of Neutron Yield Produced by 62 MeV Protons on Beryllium Target

International Nuclear Information System (INIS)

Osipenko, M.; Ripani, M.; Ricco, G.; Alba, R.; Schillaci, M.; Cosentino, L.; Del Zoppo, A.; Di Pietro, A.; Figuera, P.; Finocchiaro, P.; Maiolino, C.; Santonocito, D.; Scuderi, V.; Barbagallo, M.; Colonna, N.; Boccaccio, P.; Esposito, J.; Celentano, A.; Viberti, C.M.; Kostyukov, A.

2013-06-01

A low-power prototype of neutron amplifier, based on a 70 MeV, high current proton cyclotron being installed at LNL for the SPES RIB facility, was recently proposed within INFN-E project. This prototype uses a thick Beryllium converter to produce a fast neutron spectrum feeding a sub-critical reactor core. To complete the design of such facility the new measurement of neutron yield from a thick Beryllium target was performed at LNS. This measurement used liquid scintillator detectors to identify produced neutrons by Pulse Shape Discrimination and Time of Flight technique to measure neutron energy in the range 0.5-62 MeV. To extend the covered neutron energy range 3 He detector was used to measure neutrons below 0.5 MeV. The obtained yields were normalized to the charge deposited by the proton beam on the metallic Beryllium target. These techniques allowed to achieve a wide angular coverage from 0 to 150 degrees and to explore almost complete neutron energy interval. (authors)

The local distribution of radiation quality of a collimated fast neutron beam from 15 MeV deuterons on beryllium

International Nuclear Information System (INIS)

Fidorra, J.; Booz, J.

1978-01-01

The local distribution of radiation quality (ysub(F), ysub(D)) of a collimated fast neutron beam from 14 MeV deuterons on Beryllium was studied with a spherical 1/2 inch EG and G proportional counter simulating a diameter of 2μm. The deuterons were accelerated by the compact cyclotron CV-28 of the Kernforschungsanlage Juelich. The collimator was constructed by the Cyclotron Corporation. The mean neutron energy was 6 MeV. The measurements were performed in air and in a water phantom at a target skin distance of 125 cm. The energy deposition spectra of fast neutrons obtained at various positions were separated into three components of different radiation quality: the gamma component, the recoil proton component, and the heavy ion component

Differential cross sections for gamma-ray production by 14 MeV neutrons with several elements in structural materials

International Nuclear Information System (INIS)

Murata, Isao; Yamamoto, Junji; Takahashi, Akito

1988-01-01

Energy differential cross sections for the gamma-rays produced from the (n,xγ) reactions by 14 MeV neutrons were measured in the gamma-ray energy range from 700 keV to 10 MeV using an NaI spectrometer. Results were obtained for the 8 natural elements; C, Al, Si, Cr, Fe, Ni, Cu and Mo. For prominent discrete gamma-rays in the differential cross sections, the production cross sections were determined by measuring angular distributions with a Ge detector. The gamma-ray energy covered the range between 500 and 3000 keV. The energy distributions have been compared with the differential cross sections evaluated in the nuclear data files of JENDL-3T, ENDL and ENDF/B-IV. The evaluations in JENDL-3T agreed fairly well with the measurements concerning the continuum energy spectra for secondary photons. Discrepancies appeared, however, for Si, Cr and Ni at the energies where the discrete gamma-rays were dominant. The ENDL evaluations were largely deviated from the experimental data. The production cross sections for the discrete gamma-rays in ENDL and ENDF/B-IV were available for the comparison with some of the measured cross sections. Results are presented for C, Al and Si. (author)

Development and application of a detector for absolute measurement of neutron fluence rate in MeV region

International Nuclear Information System (INIS)

Silva Dias, M. da.

1988-01-01

The development and performance of the DTS (Dual Thin Scintillator) for the absolute measurement of the neutron fluence rate between 1 and 15 MeV is decribed. The DTS detector consists of a pair of organic scintillators in a dual configuration, where the incident produces a proton-recoil which is detected in a 2Π geometry therefore avoiding the effect of the escape of protons. Thin scintillators are used resulting in small multiple scattering corrections. The theoretical caluclations of detector efficiency and proton-recoil spectrum were performed by means of a Monte Carlos code - CARLO DTS. The calculated efficiency was compared to the experimental one at two neutron energies namely 2.446 MeV and 14.04 MeV applying the Time Correlated Associated Particle technique. The theoretical and experimental efficiencies agreed within the experimental uncertainties of 1.44% and 0.77%, respectively. The performance of the DTS has been verified in an absolute 235 U(n,f) cross section measurement between 1 and 6 MeV neutron energy. The cross section results were compared to those obtained replacing the DTS detector by the NBS (National Bureau of Standards, USA) Black Neutron Detector. The agreement was excellent in the overlapping energy interval of the two experiments (between 1 and 3 MeV), within the estimated uncertainly in the range of 1,0 to 1,7%. The agreement with the most recent evaluation from the ENDF/B-VI was excellent in almost all the energy range between 1 and 6 MeV. The 235 U(n,f) cross section, average over the 252 Cf fission neutron spectrum has been evaluated. The result including the cross section values of the present work was 1220 mb, in excellent agreement with the average value among the most recent measurements, 1227 +- 12 mb, and with the value 1213 mb, using the ENDF/B-VI data. (author) [pt

Neutron-capture cross-section measurements of 74Ge and 76Ge in the energy region 0.4-14.8 MeV for neutrinoless double β decay applications

Science.gov (United States)

Bhike, Megha; Tornow, Werner

2013-10-01

Fast neutron capture cross sections for the reactions 74Ge(n, γ)75Ge and 76Ge(n, γ)77Ge have been measured in the neutron energy region 0.4-14.8 MeV with the activation method. The results are important to identify backgrounds in the neutrinoless double- β decay experiments GERDA and MAJORANA, which use germanium as both source and detector. Isotopically enriched targets which consisted of 86% of 76Ge and 14% of 74Ge were irradiated with mono-energetic neutrons produced via 3H(p,n)3He, 2H(d,n)3He and 3H(d,n)4He reactions. The cross sections were determined relative to 197Au(n, γ)198Au, 115In(n,n')115mIn and 197Au(n,2n)196Au standard cross sections. The activities of the products were measured using high-resolution γ-ray spctroscopy. The present results are compared with the evaluated data from ENDF/B-VII.1 and TALYS.

Neutron-proton analyzing power data between 7.6 and 18.5 MeV

International Nuclear Information System (INIS)

Weisel, G.J.; Tornow, W.; Howell, C.R.; Felsher, P.D.; AlOhali, M.; Chen, Z.P.; Walter, R.L.; Lambert, J.M.; Treado, P.A.; Slaus, I.

1992-01-01

Measurements of the analyzing power A y (θ) for neutron-proton scattering have been performed at 7.6, 12.0, 14.1, 16.0, and 18.5 MeV. The experimental setup is described as are the finite-geometry corrections applied to the data. One of these corrections, due to the presence of carbon in the scintillators used for neutron detection, is discussed in detail. The A y (θ) data are compared to the predictions of the Paris and Bonn nucleon-nucleon potentials and the predictions of two phase-shift analyses, one of which incorporates charge-independence breaking effects in the 3 P waves

Neutron induced fission of U isotopes up to 100 MeV

International Nuclear Information System (INIS)

Lestone, J.P.; Gavron, A.

1993-01-01

We have developed a statistical model description of the neutron induced fission of U isotopes using densities of intrinsic states and spin cut off parameters obtained directly from appropriate Nilsson model single particle levels. The first chance fission cross sections are well reproduced when the rotational contributions to the nuclear level densities are taken into account. In order to fit the U(n,f) cross sections above the threshold of second chance fission, we need to: (1) assume that the triaxial level density enhancement is washed out at an excitation energy of ∼7 MeV above the triaxial barriers with a width of ∼1 MeV, implying a γ deformation for the first barriers of 10 degree < γ < 20 degree; and (2) include pre-equilibrium particle emission in the calculations. Above an incoming neutron kinetic energy of ∼17 MeV our statistical model U(n,f) cross sections increasingly overestimate the experimental data when so called ''good'' optical model potentials are used to calculate the compound nucleus formation cross sections. This is not surprising since at these high energies little data exists on the scattering of neutrons to help guide the choice of optical model parameters. A satisfactory reproduction of all the available U(n,f) cross sections above 17 MeV is obtained by a simple scaling of our calculated compound nucleus formation cross sections. This scaling factor falls from 1.0 at 17 MeV to 0.82 at 100 MeV

Neutron response matrix for unfolding NE-213 measurements to 21 MeV

International Nuclear Information System (INIS)

Ingersoll, D.T.; Wehring, B.W.; Johnson, R.H.

1976-01-01

A neutron response matrix from measured neutron responses of NE-213 in the energy range of 0.2 to 22 MeV is presented. An interpolation scheme was used to construct an 81-column matrix from the data of Verbinski, Burrus, Love, Zobel, and Hill. As a test of the new response matrix, the Cf-252 neutron spectrum was measured and unfolded using the new response matrix and the FORIST unfolding code. The spectrum agrees well with previous measurements at lower energies, while providing new information above 8 MeV

Measurement of cross sections for the scattering of neutrons in the energy range from 2 MeV to 4 MeV with the {sup 15}N(p,n) reaction as neutron source; Messung von Wirkungsquerschnitten fuer die Streuung von Neutronen im Energiebereich von 2 MeV bis 4 MeV mit der {sup 15}N(p,n)-Reaktion als Neutronenquelle

Energy Technology Data Exchange (ETDEWEB)

Poenitz, Erik

2010-04-26

In future nuclear facilities, the materials lead and bismuth can play a more important role than in today's nuclear reactors. Reliable cross section data are required for the design of those facilities. In particular the neutron transport in the lead spallation target of an Accelerator-Driven Subcritical Reactor strongly depends on the inelastic neutron scattering cross sections in the energy region from 0.5 MeV to 6 MeV. In the recent 20 years, elastic and inelastic neutron scattering cross sections were measured with high precision for a variety of elements at the PTB time-of-flight spectrometer. The D(d,n) reaction was primarily used for the production of neutrons. Because of the Q value of the reaction and the available deuteron energies, neutrons in the energy range from 6 MeV to 16 MeV can be produced. For the cross section measurement at lower energies, however, another neutron producing reaction is required. The {sup 15}N(p,n){sup 15}O reaction was chosen, as it allows the production of monoenergetic neutrons with up to 5.7MeV energy. In this work, the {sup 15}N(p,n) reaction was studied with focus on the suitability as a source for monoenergetic neutrons in scattering experiments. This includes the measurement of differential cross sections for the neutron producing reaction and the choice of optimum target conditions. Differential elastic and inelastic neutron scattering cross sections were measured for lead at four energies in the region from 2 MeV to 4 MeV incident neutron energy using the time-of-flight technique. A lead sample with natural isotopic composition was used. NE213 liquid scintillation detectors with well-known detection efficiencies were used for the detection of the scattered neutrons. Angle-integrated cross sections were determined by a Legendre polynomial expansion using least-squares methods. Additionally, measurements were carried out for isotopically pure {sup 209}Bi and {sup 181}Ta samples at 4 MeV incident neutron energy

Inelastic Neutron Scattering Cross Sections of Cu-63 and Cu-65 in the Energy Region 0.7 to 1.4 MeV

Energy Technology Data Exchange (ETDEWEB)

Holmqvist, B; Wiedling, T

1964-08-15

The gamma ray spectra from, the {sup 63}Cu (n, n'{gamma}) and {sup 65}Cu (n, n'{gamma}) reactions have been studied for seven neutron energies in the energy range 0.7 - 1.4 MeV using a Nal(Tl) scintillation spectrometer and time-of-flight techniques. Scatterers of natural copper have been used. Experimental excitation curves have been obtained for the two lowest excited levels in each of the Cu and Cu isotopes. The experimental (n, n') cross sections for the individual levels at 668 keV and 961 keV in {sup 63}Cu and 764 keV and 1114 keV in {sup 65}Cu have been compared to a modified Hauser-Feshbach theory for inelastic neutron scattering. This experiment has confirmed by other methods determined spins of these levels, i.e. 1/2{sup -} and 5/2{sup -} respectively.

Radiochemical study of 45Sc(n,p)45Ca and 89Y(n,p)89Sr reactions in the neutron energy range of 13.9 to 14.7 MeV

International Nuclear Information System (INIS)

Molla, N.I.; Basunia, S.; Miah, M.R.; Hossain, S.M.; Rahman, M.M.; Spellerberg, S.; Qaim, S.M.

1998-01-01

Cross sections for 45 Sc(n,p) 45 Ca and 89 Y(n,p) 89 Sr reactions were measured using the activation technique. Monoenergetic neutrons in the energy range of 13.9 to 14.7 MeV were produced using a D-T neutron generator. The purely β - emitting products 45 Ca and 89 Sr were separated radiochemically; their radioactivity was assayed via low-level β - counting. The measured data complement the available published experimental information, and agree with the results of statistical model calculations. (orig.)

Variance reduction techniques for 14 MeV neutron streaming problem in rectangular annular bent duct

Energy Technology Data Exchange (ETDEWEB)

Ueki, Kotaro [Ship Research Inst., Mitaka, Tokyo (Japan)

1998-03-01

Monte Carlo method is the powerful technique for solving wide range of radiation transport problems. Its features are that it can solve the Boltzmann`s transport equation almost without approximation, and that the complexity of the systems to be treated rarely becomes a problem. However, the Monte Carlo calculation is always accompanied by statistical errors called variance. In shielding calculation, standard deviation or fractional standard deviation (FSD) is used frequently. The expression of the FSD is shown. Radiation shielding problems are roughly divided into transmission through deep layer and streaming problem. In the streaming problem, the large difference in the weight depending on the history of particles makes the FSD of Monte Carlo calculation worse. The streaming experiment in the 14 MeV neutron rectangular annular bent duct, which is the typical streaming bench mark experiment carried out of the OKTAVIAN of Osaka University, was analyzed by MCNP 4B, and the reduction of variance or FSD was attempted. The experimental system is shown. The analysis model by MCNP 4B, the input data and the results of analysis are reported, and the comparison with the experimental results was examined. (K.I.)

Neutron total and scattering cross sections of 6Li in the few MeV region

International Nuclear Information System (INIS)

Smith, A.; Guenther, P.; Whalen, J.

1980-02-01

Neutron total cross sections of 6 Li are measured from approx. 0.5 to approx. 4.8 MeV at intervals of approx. 10 scattering angles and at incident-neutron intervals of approx.< 100 keV. Neutron differential inelastic-scattering cross sections are measured in the incident-energy range 3.5 to 4.0 MeV. The experimental results are extended to lower energies using measured neutron total cross sections recently reported elsewhere by the authors. The composite experimental data (total cross sections from 0.1 to 4.8 MeV and scattering cross sections from 0.22 to 4.0 MeV) are interpreted in terms of a simple two-level R-matrix model which describes the observed cross sections and implies the reaction cross section in unobserved channels; notably the (n;α)t reaction (Q = 4.783 MeV). The experimental and calculational results are compared with previously reported results as summarized in the ENDF/B-V evaluated nuclear data file

Measurements of the 40Ar(n, γ)41Ar radiative-capture cross section between 0.4 and 14.8 MeV

Science.gov (United States)

Bhike, Megha; Fallin, B.; Tornow, W.

2014-09-01

The 40Ar(n, γ)41Ar neutron capture cross section has been measured between 0.4 and 14.8 MeV neutron energy using the activation technique. The data are important for estimating backgrounds in argon-based neutrino and dark-matter detectors and in the neutrino-less double-beta decay search GERDA, which uses liquid argon as cooling and shielding medium. For the first time the 40Ar(n, γ)41Ar cross section has been measured for neutron energies above 1 MeV. Our results are compared to the evaluation ENDF/B-VII.1 and the calculated prediction TENDL-2013. The latter agrees very well with the present results.

Verification of KERMA factor for beryllium at neutron energy of 14.2 MeV based on charged-particle measurement

International Nuclear Information System (INIS)

Kondo, Keitaro; Ochiai, Kentaro; Murata, Isao; Konno, Chikara

2008-01-01

In previous direct measurements of nuclear heating for beryllium induced with DT neutrons, it was pointed out that the calculation with JENDL-3.2 underestimated the measured one by 25%. However, reasons of the discrepancy have not been understood clearly. Recently, we measured the α-particle emission double-differential cross section for beryllium and found that the evaluation of the 9 Be(n,2n + 2α) reaction in nuclear data libraries have some problems. We examined KERMA factors for beryllium deduced with three latest nuclear data libraries: JENDL-3.3, ENDF/B-VII.0 and JEFF-3.1. The partial KERMA factors for 9 Be(n,2n + 2α) reaction channel at incident neutron energy of 14.2 MeV deduced from these libraries were compared with a new partial KERMA factor calculated based on our experimental model. The partial KERMA factor from JENDL-3.3 was smaller by 20% than our experiment-based one. The reason of the discrepancy in the previous nuclear heating measurement comes from the smaller partial KERMA factor in JENDL-3.3, which is caused by significant underestimation of higher energy part of the α-particle emission DDX at forward emission angles

Development of quasi-monochromatic p-7Li neutron generating system for 80-210 MeV

International Nuclear Information System (INIS)

Nakao, Noriaki; Shibata, Tokushi; Nakamura, Takashi; Uwamino, Yoshitomo; Nakanishi, Noriyoshi; Kurosawa, Tadahiro; Kim, Unju.

1996-01-01

Recently the requirements for the experimental data on the response characteristics of neutron detector and the cross section for neutron generation by charged particles have been increasing for shield designing. Here, a system for quasi-monochromatic neutron generation was developed in the facility of ring-cyclotron in Institute of Physical and Chemical Sciences. In this study, H 2 + accelerated to an energy range of 80-135 MeV/n and P + to 150-210 MeV was irradiated to E4 beam course and NE102A plastic scintillator was used for monitoring the neutron flux. The amount of neutrons generated was estimated from the radioactivity of 7 Be produced in 7 Li-target. The neutron spectres thus estimated as an energy range of 80-210 MeV were presented and the lower limit of these spectres was about 20 MeV. The peaks in the range of 150 and 210 MeV were comparatively wide because of the inferiority of energy resolving power at a higher energy level. (M.N.)

Compilation and evaluation of 14-MeV neutron-activation cross sections for nuclear technology applications. Set I

Energy Technology Data Exchange (ETDEWEB)

Evain, B.P.; Smith, D.L.; Lucchese, P.

1985-04-01

Available 14-MeV experimental neutron activation cross sections are compiled and evaluated for the following reactions of interest for nuclear-energy technology applications: /sup 27/Al(n,p)/sup 27/Mg, Si(n,X)/sup 28/Al, Ti(n,X)/sup 46/Sc, Ti(n,X)/sup 47/Sc, Ti(n,X)/sup 48/Sc, /sup 51/V(n,p)/sup 51/Ti, /sup 51/V(n,..cap alpha..)/sup 48/Sc, Cr(n,X)/sup 52/V, /sup 55/Mn(n,..cap alpha..)/sup 52/V, /sup 55/Mn(n,2n)/sup 54/Mn, Fe(n,X)/sup 54/Mn, /sup 54/Fe(n,..cap alpha..)/sup 51/Cr, /sup 59/Co(n,p)/sup 59/Fe, /sup 59/Co(n,..cap alpha..)/sup 56/Mn, /sup 59/Co(n,2n)/sup 58/Co, /sup 65/Cu(n,p)/sup 65/Ni, Zn(n,X)/sup 64/Cu, /sup 64/Zn(n,2n)/sup 63/Zn, /sup 113/In(n,n')/sup 113m/In, /sup 115/In(n,n') /sup 115m/In. The compiled values are listed and plotted for reference without adjustments. From these collected results those values for which adequate supplementary information on nuclear constants, standards and experimental errors is provided are selected for use in reaction-by-reaction evaluations. These data are adjusted as needed to account for recent revisions in the nuclear constants and cross section standards. The adjusted results are subsequently transformed to equivalent cross sections at 14.7 MeV for the evaluation process. The evaluations are performed utilizing a least-squares method which considers correlations between the experimental data. 440 refs., 41 figs., 46 tabs.

The neutron-deuteron elastic scattering angular distribution at 95 MeV

Energy Technology Data Exchange (ETDEWEB)

Mermod, Philippe

2004-04-01

The neutron-deuteron elastic scattering differential cross section has been measured at 95 MeV incident neutron energy, with the Medley setup at TSL in Uppsala. The neutron-proton differential cross section has also been measured for normalization purposes. The data are compared with theoretical calculations to investigate the role of three-nucleon force effects.

Exclusive data-based modeling of neutron-nuclear reactions below 20 MeV

Science.gov (United States)

Savin, Dmitry; Kosov, Mikhail

2017-09-01

We are developing CHIPS-TPT physics library for exclusive simulation of neutron-nuclear reactions below 20 MeV. Exclusive modeling reproduces each separate scattering and thus requires conservation of energy, momentum and quantum numbers in each reaction. Inclusive modeling reproduces only selected values while averaging over the others and imposes no such constraints. Therefore the exclusive modeling allows to simulate additional quantities like secondary particle correlations and gamma-lines broadening and avoid artificial fluctuations. CHIPS-TPT is based on the formerly included in Geant4 CHIPS library, which follows the exclusive approach, and extends it to incident neutrons with the energy below 20 MeV. The NeutronHP model for neutrons below 20 MeV included in Geant4 follows the inclusive approach like the well known MCNP code. Unfortunately, the available data in this energy region is mostly presented in ENDF-6 format and semi-inclusive. Imposing additional constraints on secondary particles complicates modeling but also allows to detect inconsistencies in the input data and to avoid errors that may remain unnoticed in inclusive modeling.

Energy Dependence of Fission Product Yields from {sup 235}U, {sup 238}U and {sup 239}Pu for Incident Neutron Energies Between 0.5 and 14.8 MeV

Energy Technology Data Exchange (ETDEWEB)

Gooden, M.E., E-mail: m_gooden@lanl.gov [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Arnold, C.W. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Becker, J.A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Bhatia, C. [McMaster University, Ontario (Canada); Bhike, M. [Department of Physics, Duke University,Durham, North Carolina 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 (United States); Bond, E.M.; Bredeweg, T.A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Fallin, B. [Department of Physics, Duke University,Durham, North Carolina 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 (United States); Fowler, M.M. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Howell, C.R. [Department of Physics, Duke University,Durham, North Carolina 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 (United States); Kelley, J.H. [Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 (United States); Department of Physics, North Carolina State University, Raleigh, North Carolina 27605 (United States); Krishichayan [Department of Physics, Duke University,Durham, North Carolina 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 (United States); Macri, R. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Rusev, G. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Ryan, C.; Sheets, S.A.; Stoyer, M.A.; Tonchev, A.P. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Tornow, W. [Department of Physics, Duke University,Durham, North Carolina 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 (United States); and others

2016-01-15

Fission Product Yields (FPY) have historically been one of the most observable features of the fission process. They are known to have strong variations that are dependent on the fissioning species, the excitation energy, and the angular momentum of the compound system. However, consistent and systematic studies of the variation of these FPY with energy have proved challenging. This is caused primarily by the nature of the experiments that have traditionally relied on radiochemical procedures to isolate specific fission products. Although radiochemical procedures exist that can isolate all products, each element presents specific challenges and introduces varying degrees of systematic errors that can make inter-comparison of FPY uncertain. Although of high importance in fields such as nuclear forensics and Stockpile Stewardship, accurate information about the energy dependence of neutron induced FPY are sparse, due primarily to the lack of suitable monoenergetic neutron sources. There is a clear need for improved data, and to address this issue, a collaboration was formed between Los Alamos National Laboratory (LANL), Lawrence Livermore National Laboratory (LLNL) and the Triangle Universities Nuclear Laboratory (TUNL) to measure the energy dependence of FPY for {sup 235}U, {sup 238}U and {sup 239}Pu. The measurements have been performed at TUNL, using a 10 MV Tandem Van de Graaff accelerator to produce monoenergetic neutrons at energies between 0.6 MeV to 14.8 MeV through a variety of reactions. The measurements have utilized a dual-fission chamber, with thin (10-100 μg/cm2) reference foils of similar material to a thick (100-400 mg) activation target held in the center between the chambers. This method allows for the accurate determination of the number of fissions that occurred in the thick target without requiring knowledge of the fission cross section or neutron fluence on target. Following activation, the thick target was removed from the dual-fission chamber

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

Neutron-deuteron analyzing power data at 19.0 MeV

International Nuclear Information System (INIS)

Weisel, G. J.; Tornow, W.; Crowe, B. J. III; Crowell, A. S.; Esterline, J. H.; Howell, C. R.; Kelley, J. H.; Macri, R. A.; Pedroni, R. S.; Walter, R. L.; Witala, H.

2010-01-01

Measurements of neutron-deuteron (n-d) analyzing power A y (θ) at E n =19.0 MeV are reported at 16 angles from θ c.m. =46.7 to 152.0 deg. The objective of the experiment is to better characterize the discrepancies between n-d data and the predictions of three-nucleon calculations for neutron energies above 16.0 MeV. The experiment used a shielded neutron source, which produced polarized neutrons via the 2 H(d-vector,n-vector) 3 He reaction, a deuterated liquid scintillator center detector (CD) and liquid-scintillator neutron side detectors. A coincidence between the CD and the side detectors isolated the elastic-scattering events. The CD pulse height spectrum associated with each side detector was sorted by using pulse-shape discrimination, time-of-flight techniques, and by removing accidental coincidences. A Monte Carlo computer simulation of the experiment accounted for effects due to finite geometry, multiple scattering, and CD edge effects. The resulting high-precision data (with absolute uncertainties ranging from 0.0022 to 0.0132) have a somewhat lower discrepancy with the predictions of three-body calculations, as compared to those found at lower energies.

The use of multi-energy-group neutron diffusion theory to numerically evaluate the relative utility of three dial-detector neutron porosity well logging tools

International Nuclear Information System (INIS)

Zalan, T.A.

1988-01-01

Multi-energy-group neutron diffusion theory is used to numerically evaluate the utility of two different dual-detector neutron porosity logging devices, a 14 MeV (accelerator) neutron source - epithermal neutron detector device and a 4 MeV neutron source - capture gamma-ray detector device, relative to the traditional 4 MeV neutron source - thermal neutron detector device. Fast and epithermal neutron diffusion parameters are calculated using Monte Carlo - derived neutron flux distributions. Thermal parameters are calculated from tabulated cross sections. An existing analytical method to describe the transport of gamma-rays through common earth materials is modified in order to accommodate the modeling of the 4 MeV neutron - capture gamma-ray device. The 14 MeV neutron - epithermal neutron device is found to be less sensitive to porosity than the 4 MeV neutron - capture gamma-ray device, which in turn is found to be less sensitive to porosity than the traditional 4 MeV neutron - thermal neutron device. Salinity effects are found to be comparable for the 4 MeV neutron - capture gamma-ray and 4 MeV neutron - thermal neutron devices. The 4 MeV neutron capture gamma-ray measurement is found to be deepest investigating

14 MeV proton activation analysis

International Nuclear Information System (INIS)

Constantinescu, B.; Ivanov, E.; Plostinaru, D.; Popa-Nemoiu, A.; Pascovichi, G.

1985-01-01

A fast nuclear nondestructive method for protein analysis using the 14 MeV proton activation has been developed. The total nitrogen content was measured through the reaction: 14 N (p,n) 14 O, (Tsub(1/2)=71 s). The 14 O activity was detected by means of its characteristic 2.312 MeV gamma-ray line with a NaI(Tl) detector. For a fast determination of a large number of samples a mechanized sistem reacting a rate of one sample per minute has been developed. The laboratory electronics comprises a multichannel analyser, a PDP computer and an electronic module comtroller. Comparison of the results obtained by the method described and the classical Kjeldal technique for samples of various cereal grains (soya bean seads, wheat, barley and corn) showed good correlation. A problem of the analysis of the whole protein region on corn and soya-bean seads, where this region is thicker (0,2 - 2 mm), is mentioned. In this case flour was proposed to be used to obtain a protein homogeneous sample and the irradiaton dose for a sample was about 33,000 Gy, mainly (99%) from protons (27 s x 100 nA x 14 MeV)

Conceptual design of 30 MeV magnet system used for BNCT epithermal neutron source

International Nuclear Information System (INIS)

Slamet Santosa; Taufik

2015-01-01

Conceptual design of 30 MeV Magnet System Used for BNCT Epithermal Neutron Source has been done based on methods of empirical model of basic equation, experiences of 13 MeV cyclotron magnet design and personal communications. In the field of health, cyclotron can be used as an epithermal neutron source for Boron Neutron Capture Therapy (BNCT). The development of cyclotron producing epithermal neutrons for BNCT has been performed at Kyoto University, of which it produces a proton beam current of 1.1 mA with energy of 30 MeV. With some experiences on 13 MeV cyclotron magnet design, to support BNCT research and development we performed the design studies of 30 MeV cyclotron magnet system, which is one of the main components of the cyclotron for deflecting proton beam into circular trajectory and serves as beam focusing. Results of this study are expected to define the parameters of particular cyclotron magnet. The scope of this study includes the study of the parameters component of the 30 MeV cyclotron and magnet initial parameters. The empirical method of basic equation model is then corroborated by a simulation using Superfish software. Based on the results, a 30 MeV cyclotron magnet for BNCT neutron source enables to be realized with the parameters of B 0 = 1.06 T, frequency RF = 64.733938 ≈ 65 MHz, the external radius of 0.73 m, the radius of the polar = 0.85 m, BH = 1.95 T and a gap hill of 4 cm. Because proton beam current that be needed for BNCT application is very large, then in the calculation it is chosen a great focusing axial νz = 0.630361 which can generate B V = 0.44 T. (author)

Characterization of a diamond detector to be used as neutron yield monitor during the in-vessel calibration of JET neutron detectors in preparation of the DT experiment

International Nuclear Information System (INIS)

Pillon, Mario; Angelone, Maurizio; Batistoni, Paola; Loreti, Stefano; Milocco, Alberto

2016-01-01

Highlights: • A diamond detector has been characterized for use as neutron yield monitor of a portable 14 MeV neutron generator. • The system will be used for the 14 MeV calibration of JET neutron detector. • The results and the performances of the monitor are very satisfactory in term of accuracy and reliability. - Abstract: A new Deuterium-Tritium (DT) campaign is planned at JET. An accurate calibration for the 14 MeV neutron yield monitors is necessary. In order to perform the calibration a 14 MeV Neutron Generator with suitable intensity (∼10 8 n/s) will be used. Due to the intensity change during the Neutron Generator lifetime it would be necessary to monitor continuously the neutron emission intensity during the calibration using a compact detector attached to it. A high quality diamond detector has been chosen as one of the monitors. This detector has been fully characterized at the 14 MeV Frascati Neutron Generator facility. The characterization procedure and the resulting 14 MeV neutron response of the detector are described in this paper together with the obtained uncertainties.

Measurements of double-differential neutron emission cross sections of {sup 6}Li and {sup 7}Li for 18 MeV neutrons

Energy Technology Data Exchange (ETDEWEB)

Ibaraki, Masanobu; Baba, Mamoru; Matsuyama, Shigeo; Sanami, Toshiya; Win, T.; Miura, Takako; Hirakawa, Naohiro [Tohoku Univ., Sendai (Japan). Faculty of Engineering

1997-03-01

Double-differential neutron emission cross sections of {sup 6}Li and {sup 7}Li were measured for 18 MeV neutrons at Tohoku University 4.5 MV Dynamitron facility. Neutron emission spectra were obtained down to 1 MeV at 13 angles with energy resolution good enough to separate discrete levels. A care was taken to eliminate the sample-dependent background due to parasitic neutrons. Experimental results were in fair agreement with the JENDL-3.2 data and a simple model considering a three-body breakup process and discrete level excitations. (author)

Neutron data library for transactinides at energies up to 100 MeV

Energy Technology Data Exchange (ETDEWEB)

Korovin, Y.A.; Artisyuk, V.V.; Konobeyev, A.Y. [Obninsk Institute of Nuclear Power Engineering (Russian Federation)

1995-10-01

New neutron data library for transactinides is briefly described. The library includes evaluated cross-sections for fission and threshold neutron induced reactions for isotopes of U, Np and Pu at energies 0-100 MeV.

Observations on late effects in mice exposed to 400 MeV neutrons

CERN Document Server

Covelli, V; Bassani, B; Baarli, Johan; Bianchi, M; Metalli, P; Covelli, V; Di Paola, M; Bassani, B; Baarli, J no 2; Bianchi, M no 2; Metalli, P

1976-01-01

Life-long observations on mortality and pathology at death were carried out on groups of mice irradiated with 250 kV X-rays or exposed to a 400 MeV neutron beam, both directly and after attenuation corresponding to the maximum dose build-up region, at comparable dose-rates. Doses up to 84 rad of 400 MeV neutrons and up to 200 rad of X-rays showed no effect on the longevity of the animals, which suggests an upper limit to the r.b.e. for life-shortening of approximately 2·5. Similar conclusions were drawn from the data on all types of leukemias. For all other neoplasms, the age-specific death-rate showed a similar shortening of the latency times for groups of mice irradiated with 0–84 rad of 400 MeV direct neutrons and 0–400 rad of X-rays, also suggesting an upper limit to the r.b.e. slightly higher than that previously indicated for life-shortening. No definite effect was observed after exposure to the attenuated neutron beam at the doses used in these experiments.

Analysis of a neutron scattering integral experiment on iron for neutron energies from 1 to 15 MeV

International Nuclear Information System (INIS)

Cramer, S.N.; Oblow, E.M.

1976-11-01

Monte Carlo calculations were made to analyze the results of an integral experiment with an iron sample to determine the adequacy of neutron scattering cross section data for iron. The experimental results analyzed included energy-dependent NE-213 detector count rates at a scattering angle of 90 deg and pulse-height spectra for scattered neutrons produced in an iron ring pulsed with a 1- to 20-MeV neutron source. The pulse-height data were unfolded to generate secondary neutron spectra at 90 deg as a function of incident neutron energy. Multigroup Monte Carlo calculations using the MORSE code and ENDF/B-IV cross sections were made to analyze all reported results. Discrepancies between calculated and measured responses were found for inelastic scattering reactions in the range from 1 to 4 MeV. These results were related to deficiencies in ENDF/B-IV iron cross section data

Low-temperature irradiation of niobium with 15-MeV neutrons

International Nuclear Information System (INIS)

Kerchner, H.R.; Coltman, R.R. Jr.; Klabunde, C.E.; Sekula, S.T.

1978-01-01

Niobium was irradiated at 4.2 K with high energy d-Be neutrons to a fluence of 3.7x10 15 n/cm 2 . The neutrons were generated at the Oak Ridge Isochronous Cyclotron by the breakup reaction of 40-MeV deuterons in a thick Be target. The resulting neutron energy spectrum was broadly peaked near 15 MeV. The 0.012-cm-diameter wire sample (RRR=200) was situated in a uniform transverse magnetic field. The critical current, flux flow resistance, and normal state resistance were measured by using a standard four-terminal technique. The critical current density and the flux flow resistivity were observed to increase with irradiation and to decrease toward the preirradiation values with subsequent isochronal annealing between 4.2 K and 360 K. Using recent theories of flux line lattice deformation, the elementary pinning force is deduced and the result is compared to theoretical calculations. (Auth.)

Integral activation experiment of fusion reactor materials with d-Li neutrons up to 55 MeV

Energy Technology Data Exchange (ETDEWEB)

Maekawa, Fujio; Ikeda, Yujiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Moellendorff, Ulrich von [Forschungszentrum Karlsruhe, Karlsruhe (Germany); Wada, Masayuki [Business Automation Co., Ltd., Tokyo (Japan)

2000-03-01

An integral activation experiment of fusion reactor materials with a deuteron-lithium neutron source was performed. Since the maximum energy of neutrons produced was 55 MeV, the experiment with associated analysis was one of the first attempts for extending the energy range beyond 20 MeV. The following keywords represent the present study: d-Li neutrons, 55 MeV, dosimetry, SAND-II, spectrum adjustment, LA-150, MCNP, McDeLi, IFMIF, fusion reactor materials, integral activation experiment, low-activation, F82H, vanadium-alloy, IEAF, ALARA, and sequential charged particle reaction. (author)

Structures in 20O from the 14C(7Li, p) reaction at 44 MeV

International Nuclear Information System (INIS)

Bohlen, H.G.; Oertzen, W. von; Kokalova, T.; Wheldon, C.; Milin, M.; Dorsch, T.; Kruecken, R.; Faestermann, T.; Mahgoub, M.; Hertenberger, R.; Wirth, H.F.

2011-01-01

We have studied the multi-nucleon transfer reaction 14 C( 7 Li, p) at E Lab ( 7 Li) = 44 MeV populating states of the neutron-rich oxygen isotope 20 O. The experiments have been performed at the Munich Tandem accelerator using the high-resolution Q3D magnetic spectrometer, with an overall energy resolution of 45keV. States were populated up to 20MeV excitation energy -65 states have been identified in the analysis, among which 42 are new. Rotational bands are proposed in terms of underlying intrinsic reflection-asymmetric cluster and prolate molecular structures (namely 14 C x 2n x α) as parity doublet bands. A rectangular oblate structure is suggested for some very narrow states at high excitation energies. (orig.)

Evaluation of the n + 3H Cross Section at En=14 MeV

Energy Technology Data Exchange (ETDEWEB)

Navratil, P; Quaglioni, S; Anderson, J D; Dietrich, F S; McNabb, D P; Hale, G M

2010-02-10

The n + {sup 3}H cross section is important for NIF diagnostics. As the d-{sup 3}H fusion at NIF generates neutrons with an energy of 14 MeV, the precise knowledge of the n + {sup 3}H cross section and in particular the elastic cross section at that energy is crucial. Experimental data at E{sub n} = 14 MeV are not accurate with large disagreements among different sets of measurements. On the other hand, the mirror reaction p-{sup 3}He is well studied and accurate data are available in a wide range of proton energies. We use several theoretical approaches to evaluate the n-{sup 3}H cross section by fine-tuning the theory to reproduce the p-{sup 3}He elastic differential cross sections. The good agreement between the R-matrix analysis and scaled ab initio calculations gives us confidence that our evaluated n + {sup 3}H cross section is accurate with an uncertainty on the order of 5%.

Measurements of the 40Ar(n, γ41Ar radiative-capture cross section between 0.4 and 14.8 MeV

Directory of Open Access Journals (Sweden)

Megha Bhike

2014-09-01

Full Text Available The 40Ar(n, γ41Ar neutron capture cross section has been measured between 0.4 and 14.8 MeV neutron energy using the activation technique. The data are important for estimating backgrounds in argon-based neutrino and dark-matter detectors and in the neutrino-less double-beta decay search GERDA, which uses liquid argon as cooling and shielding medium. For the first time the 40Ar(n, γ41Ar cross section has been measured for neutron energies above 1 MeV. Our results are compared to the evaluation ENDF/B-VII.1 and the calculated prediction TENDL-2013. The latter agrees very well with the present results.

Neutron spectrum at 900 from 800 MeV (p,n) reactions on a Ta target

International Nuclear Information System (INIS)

Howe, S.D.; Lisowski, P.W.; King, N.S.P.; Russell, G.J.; Donnert, H.J.

1979-01-01

The neutron time-of-flight spectrum produced by a thick tantalum target bombarded by 800-MeV protons was measured at an angle of 90 0 . The data were taken at the Weapons Neutron Research facility by use of a cylindrical Ta target with a radius of 1.27 cm and a length of 15 cm. An NE-213 liquid scintillator was used to detect the neutrons over an energy range of 0.5 to 350 MeV. The neutron yield is presented and compared to a intranuclear-cascade/evaporation model prediction. 3 figures

V79 survival following simultaneous or sequential irradiation by 15-MeV neutrons and 60Co photons

International Nuclear Information System (INIS)

Higgins, P.D.; DeLuca, P.M. Jr.; Pearson, D.W.; Gould, M.N.

1983-01-01

A unique tandem source irradiation facility, composed of an intense d-T neutron source and a 60 Co teletherapy unit, was used to investigate biological responses for different neutron/photon configurations. V79 Chinese hamster cells, attached as monolayers in log-phase growth, were irradiated at 37 degrees C by either 14.8-MeV neutrons, 60 Co, or a mixture of 40% neutrons and 60% photons in simultaneous or sequential application. Measurements of cell survival indicate an increased effectiveness in cell killing for simultaneously administered neutrons and photons compared to that measured or predicted for sequentially applied beam modalities. An understanding of the magnitude of these interactive effects is important both for calculating accurate effective doses for neutron radiotherapy of deep-seated tumors, for which the photon component is appreciable, and for determination of environmental hazards to people occupationally exposed to mixtures of photons and neutrons

V79 survival following simultaneous or sequential irradiation by 15-MeV neutrons and 60Co photons

International Nuclear Information System (INIS)

Higgins, P.D.; DeLuca, P.M. Jr.; Pearson, D.W.; Gould, M.N.

1983-01-01

A unique tandem source irradiation facility, composed of an intense d-T neutron source and a 60 Co teletherapy unit, was used to investigate biological responses for different neutron/photon configurations. V79 Chinese hamster cells, attached as monolayers in log-phase growth, were irradiated at 37 0 C by either 14.8-MeV neutrons, 60 Co, or a mixture of 40% neutrons and 60% photons in simultaneous or sequential application. Measurements of cell survival indicate an increased effectiveness in cell killing for simultaneously administered neutrons and photons compared to that measured or predicted for sequentially applied beam modalities. An understanding of the magnitude of these interactive effects is important both for calculating accurate effective doses for neutron radiotherapy of deep-seated tumors, for which the photon component is appreciable, and for determination of environmental hazards to people occupationally exposed to mixtures of photons and neutrons

Determination of the cross section for (n,p) and (n,α) reactions on 165Ho at 13.5 and 14.8 MeV

International Nuclear Information System (INIS)

Luo, Junhua; An, Li; Jiang, Li; He, Long

2015-01-01

Activation cross-sections for the 165 Ho(n,p) 165 Dy and 165 Ho(n,α) 162 Tb reactions were measured by means of the activation method at 13.5 and 14.8 MeV, to resolve inconsistencies in existing data. A neutron beam produced via the 3 H(d,n) 4 He reaction was used. Statistical model calculations were performed using the nuclear-reaction codes EMPIRE-3.2 Malta and TALYS-1.6 with default parameters, at neutron energies varying from the reaction threshold to 20 MeV. Results are also discussed and compared with some corresponding values found in the literature. The calculational results on the 165 Ho(n,α) 162 Tb reaction agreed fairly well with experimental data, but there were large discrepancies in the results for the 165 Ho(n,p) 165 Dy reaction. - Highlights: • 27 Al(n,α) 24 Na was used as a monitor for neutron fleunce. • The cross sections for the 165 Ho(n,p) 165 Dy and 165 Ho(n,α) 162 Tb reactions were measured at 13.5 and 14.8 MeV neutron energies. • Nuclear reaction codes TALYS-1.6 and EMPIRE-3.2 Malta were used to model the reactions. • Inconsistency with previous data and with model calculations are noted

Measurements of the prompt neutron spectra in 233U, 235U, 239Pu thermal neutron fission in the energy range of 0.01-5 MeV and in 252Cf spontaneous fission in the energy range of 0.01-10 MeV

International Nuclear Information System (INIS)

Starostov, B.I.; Semenov, A.F.; Nefedov, V.N.

1978-01-01

The measurement results on the prompt neutron spectra in 233 U, 235 U, 239 Pu thermal neutron fission in the energy range of 0.01-5 MeV and in 252 Cf spontaneous fission in the energy range of 0.01-10 MeV are presented. The time-of-flight method was used. The exceeding of the spectra over the Maxwell distributions is observed at E 252 Cf neutron fission spectra. The spectra analysis was performed after normalization of the spectra and corresponding Maxwell distributions for one and the same area. In the range of 0.05-0.22 MeV the yield of 235 U + nsub(t) fission neutrons is approximately 8 and approximately 15 % greater than the yield of 252 Cf and 239 Pu + nsub(t) fission neutrons, respectively. In the range of 0.3-1.2 MeV the yield of 235 U + nsub(t) fission neutrons is 8 % greater than the fission neutron yield in case of 239 Pu + nsub(t) fission. The 235 U + nsub(t) and 233 U + nsub(t) fission neutron spectra do not differ from one another in the 0.05-0.6 MeV range

Partial Cross Sections of Neutron-Induced Reactions on nCu at En = 6, 8, 10, 12, 14, and 16 MeV for 0νββ Background Studies

Science.gov (United States)

Gooden, M. E.; Fallin, B. A.; Finch, S. W.; Kelley, J. H.; Howell, C. R.; Rusev, G.; Tonchev, A. P.; Tornow, W.; Stanislav, V.

2014-05-01

Partial cross-section measurements of (n,n'γ) reactions on natCu were carried out at TUNL using monoenergetic neutrons at six energies of En = 6, 8, 10, 12, 14, 16 MeV. These studies were performed to provide accurate cross-section data on materials abundant in experimental setups involving HPGe detectors used to search for rare events, like the neutrino-less double-beta decay of 76Ge. Spallation and (α,n) neutrons are expected to cause the largest source of external background in the energy region of interest. At TUNL pulsed neutron beams were produced via the 2H(d,n)3He reaction and the deexcitation γ rays from the reaction natCu(n,xγ) were detected with clover HPGe detectors. Cross-section results for the strongest transtions in 63Cu and 65Cu will be reported, and will compared to model calculations and to data recently obtained at LANL with a white neutron beam.

Compendium on neutron spectra in criticality accident dosimetry

International Nuclear Information System (INIS)

Ing, H.

1978-01-01

Graphical and tabulated neutron spectra are presented: from selected critical assemblies; from critical solutions; of fission neutrons through shielding; of H 2 O-moderated fission neutrons through shielding; of D 2 O-moderated fission neutrons through shielding; of fission neutrons reflected from various materials; from the D(T, 4 He)n reaction (''14 MeV'' neutrons) through shielding and of ''14 MeV'' neutrons reflected from various materials

Evaluation of neutron cross sections to 40 MeV for 5456Fe

International Nuclear Information System (INIS)

Arthur, E.D.; Young, P.G.

1980-01-01

Cross sections for neutron-induced reactions on 54 56 Fe were calculated by employing several nuclear models: optical, Hauser-Feshbach, preequilibrium and DWBA - in the energy range between 3 and 40 MeV. As a prelude to the calculations, the necessary input parameters were determined or verified through analysis of a large body of experimental data for both neutron- and proton-induced reactions in this mass and energy region. This technique also led to cross sections in which the simultaneous influence of available data types added to their consistency and reliability. Calculated cross sections as well as neutron and gamma-ray emission spectra were incorporated into an ENDF evaluation suitable for use to 40 MeV. 12 figures, 1 table

A neutron survey meter with sensitivity extended up to 400 MeV

International Nuclear Information System (INIS)

Birattari, C.; Silari, M.

1992-01-01

The well-known Andersson-Braun rem counter is widely employed for radiation protection purposes, but its efficiency shows a marked decrease for neutron energies above about 10 MeV. Since the availability of a survey meter with a good sensitivity to higher energies can be very useful, for instance, at many particle accelerator facilities, a neutron monitor with a response function extended up to 400 MeV has been achieved by modifying the structure of the moderator-attenuator of a commercial instrument. The first experimental tests carried out to verify the response of the new monitor both to low and high energy neutrons are reported. A comparison with the response function of three conventional commercial rem counters is presented. (author)

Development of neutron-monitor detectors applicable for energies up to 100 MeV

Energy Technology Data Exchange (ETDEWEB)

Sato, Tatsuhiko; Endo, Akira; Yamaguchi, Yasuhiro; Kim, Eunjoo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Nakamura, Takashi [Tohoku Univ., Sendai, Miyagi (Japan)

2003-03-01

For the purpose of monitoring of neutron doses in high energy accelerator facilities, we have been developing neutron detectors which are applicable for neutron energies up to 100 MeV. The present paper reports characteristics of a phoswitch-type neutron detector which is composed of a liquid organic scintillator and {sup 6}Li+ZnS(Ag) sheets. (author)

Comments on (n, charged particle) reactions at E/sub n/ = 14 MeV

International Nuclear Information System (INIS)

Haight, R.C.

1984-01-01

The study of charged particles produced by bombarding materials with 14 MeV neutrons is important for the development of fusion reactors and for biomedical applications as well as for the basic understanding of nuclear reactions. Several experimental techniques for investigating these reactions are discussed here. The interpretation of the data requires the consideration of several possible reaction mechanisms including equilibrium and preequilibrium particle emission and, for light nuclei, sequential particle emission, final state interactions, and the effect of resonances. 17 references

Energy measurement of prompt fission neutrons in 239Pu(n,f) for incident neutron energies from 1 to 200 MeV

CERN Document Server

Chatillon, A; Granier, Th; Laurent, B; Taïeb, J; Noda, S; Haight, R C; Devlin, M; Nelson, R O; O’Donnell, J M

2010-01-01

Prompt fission neutron spectra in the neutron-induced fission of 239Pu have been measured for incident neutron energies from 1 to 200 MeV at the Los Alamos Neutron Science Center. Preliminary results are discussed and compared to theoretical model calculation.

Determination of 233U, 235U, 238U and 239Pu fission yields induced by fission and 14.7 MeV neutrons

International Nuclear Information System (INIS)

Laurec, Jean; Adam, Albert; Bruyne, Thierry de.

1981-12-01

The 233 U, 235 U, 238 U, 239 Pu fission yields have been determined by a radiochemical method. A target and a fission chamber made of same fissible material are irradied together. The total fission number is measured from the fission chamber. The fission product activities are directly measured on the target using calibrated Ge-Li detectors. The fissible material masses are determined by alpha and mass spectrometries. The irradiations were made on the critical assemblies PROSPERO and CALIBAN and on the 14 MeV neutron generator of C.E. VALDUC. 3 to 5% fission yield errors are got for the most measured nuclides: 95 Zr, 97 Zr, 99 Mo, 103 Ru, 131 I, 132 Te, 140 Ba, 141 Ce, 143 Ce, 144 Ce, 147 Nd [fr

The polarization of MeV neutrons elastically scattered from 4He

International Nuclear Information System (INIS)

Bond, J.E.; Firk, F.W.K.

1976-01-01

The analyzing power of 4 He for neutron elastic scattering has been measured at four angles between 20 0 and 80 0 (lab) throughout the energy range 1.5-6.0 MeV using a double-scattering method. The intense flux of polarized neutrons was generated via the reactions Pb(γ, n)→ 12 C(n, n(pol.) 12 C, and the magnitude of the polarization of the neutron beam measured absolutely in a separate double-scattering experiment. Neutron energies were determined with a nanosecond time-of-flight spectrometer, and the generalized neutron spin-precession method was used to minimize systematic uncertainties. (Auth.)

Measurement of formation cross sections of short-lived nuclei by 14 MeV neutron. Nd, Sm, Dy, Er, Yb

Energy Technology Data Exchange (ETDEWEB)

Sakane, H.; Yamamoto, H.; Kawade, K. [Nagoya Univ. (Japan). School of Engineering; Iida, T.; Takahashi, A.

1997-03-01

Eight neutron activation cross sections producing the nuclei with half-lives between 3 min and 24 min were obtained at the energy range between 13.4 and 14.9 MeV by activation method. The cross sections were {sup 146}Nd(n,p){sup 146}Pr, {sup 154}Sm(n,{alpha}){sup 151}Nd, {sup 162}Dy(n,p){sup 162}Tb, {sup 163}Dy(n,np){sup 162}Tb, {sup 163}Dy(n,p){sup 163}Tb, {sup 164}Dy(n,p){sup 164}Tb, {sup 170}Er(n,{alpha}){sup 167}Dy, {sup 174}Yb(n,p){sup 170}Tm. {sup 163}Dy(n,np){sup 162}Tb (T{sub 1/2}=7.7 min) was obtained for the first time. Present results are compared with previous results and the evaluated data of JENDL-3 and ENDF/B-VI. There are some discrepancies between present results and the JENDL-3 and ENDF/B-VI. (author)

SCANDAL -- A facility for elastic neutron scattering studies in the 50--130 MeV range

International Nuclear Information System (INIS)

Klug, J.; Blomgren, J.; Atac, A.; Bergenwall, B.; Dangtip, S.; Elmgren, K.; Johansson, C.; Olsson, N.; Prokofiev, A.V.; Rahm, J.; Oberstedt, A.; Tovesson, F.; Eudes, Ph.; Haddad, F.; Kerveno, M.; Kirchner, T.; Lebrun, C.; Stuttge, L.; Slypen, I.; Michel, R.; Neumann, S.; Herpers, U.

2001-01-01

A facility for detection of scattered neutrons in the energy interval 50--130 MeV, SCANDAL (SCAttered Nucleon Detection AssembLy), has recently been installed at the 20--180 MeV neutron beam facility of the The Svedberg Laboratory, Uppsala. It is primarily intended for studies of elastic neutron scattering, but can be used for the (n,p) and (n,d) reaction experiments as well. The performance of the spectrometer is illustrated in measurements of the (n,p) and (n,n) reactions on 1 H and 12 C. In addition, the neutron beam facility is described in some detail

SCANDAL--a facility for elastic neutron scattering studies in the 50-130 MeV range

CERN Document Server

Klug, J; Atac, A; Bergenwall, B; Dangtip, S; Elmgren, K; Johansson, C; Olsson, N; Pomp, S; Prokofiev, A V; Rahm, J; Tippawan, U; Jonsson, O; Nilsson, L; Renberg, P U; Nadel-Turonski, P; Ringbom, A; Oberstedt, A; Tovesson, F; Blideanu, V; Le Brun, C; Lecolley, J F; Lecolley, F R; Louvel, M; Marie, N; Schweitzer, C; Varignon, C; Eudes, P; Haddad, F; Kerveno, M; Kirchner, T; Lebrun, C; Stuttgé, L; Slypen, I; Smirnov, A N; Michel, R; Neumann, S; Herpers, U

2002-01-01

A facility for detection of scattered neutrons in the energy interval 50-130 MeV, SCAttered Nucleon Detection AssembLy (SCANDAL), has recently been installed at the 20-180 MeV neutron beam facility of The Svedberg Laboratory, Uppsala. It is primarily intended for studies of elastic neutron scattering, but can be used for (n,p) and (n,d) reaction experiments as well. The performance of the spectrometer is illustrated in measurements of the (n,p) and (n,n) reactions on sup 1 H and sup 1 sup 2 C. In addition, the neutron beam facility is described in some detail.

Calibration of a large multi-element neutron counter in the energy range 85-430 MeV

CERN Document Server

Strong, J A; Esterling, R J; Garvey, J; Green, M G; Harnew, N; Jane, M R; Jobes, M; Mawson, J; McMahon, T; Robertson, A W; Thomas, D H

1978-01-01

Describes the calibration of a large 60 element neutron counter with a threshold of 2.7 MeV equivalent electron energy. The performance of the counter has been measured in the neutron kinetic energy range 8.5-430 MeV using a neutron beam at the CERN Synchrocyclotron. The results obtained for the efficiency as a function of energy are in reasonable agreement with a Monte Carlo calculation. (7 refs).

Exposure times and ratio of readings produced by irradiation of thermoluminescence dosemeters in PTB neutron standard fields between 0.1 MeV and 19 MeV

International Nuclear Information System (INIS)

Jahr, R.; Guldbakke, S.; Cosack, M.

1979-06-01

6 LiF and 7 LiF thermoluminescence dosimeters (TLD) irradiated in a standard field of monoenergetic neutrons (Esub(n) = 0.1 MeV to 19 MeV), respond as well to the photon as to the neutron component of this radiation field. The ratio of the two TLD readings as well as the duration of irradiation required to obtain a preset TLD reading are calculated as a function of the neutron energy. (orig.) [de

Fusion spectrum neutron source computation in "6LiD convertor for HFETR

International Nuclear Information System (INIS)

Sun Shouhua; Hu Yifei; Ye Bin

2014-01-01

A computation model of 14 MeV neutron from the "6LiD convertor has been established, the 14 MeV neutron sources and flux in the irradiation samples from the "6LiD convertor and the core have been computed separately, the neutron spectrum in the irradiation samples have been computed, too. The results show that the neutron sources that over 13 MeV account for 1 MeV above in the "6LiD convertor is 25.7%, 24.6% respectively, 14 MeV neutron sources get 4.31 × 10"1"3 n_T·s"-"1, 3.34 × 10"1"3 n_T·s"-"1, 14 MeV neutron flux get 2.66 × 10"1"0 n_T·cm"-"2·s"-"1, 3.53 × 10"1"0 n_T·cm"-"2·s"-"1, as He and H_2O charged in the irradiation capsule. (authors)

Measurement of double differential cross sections of secondary neutrons in the incident energy range 9-13 MeV

International Nuclear Information System (INIS)

Tang Hongqing; Qi Bujia; Zhou Zuying; Sa Jun; Ke Zunjian; Sui Qingchang; Xia Haihong; Shen Guanren

1992-01-01

The status and technique of double differential cross section measurement of secondary neutrons in the incident neutron energy range 9 to 13 MeV is reviewed with emphasis on the work done at CIAE. There are scarce measurements of secondary neutron double differential cross sections in this energy region up to now. A main difficulty for this is lack of an applicable monoenergetic neutron source. When monoenergetic neutron energy reaches 8 Me/v, the break-up neutrons from the d + D or p + T reaction starts to become significant. It is difficult to get a pure secondary neutron spectrum induced only by monoenergetic neutrons. To solve this problem an abnormal fast neutron TOF facility was designed and tested. Double differential neutron emission cross sections of 238 U and 209 Bi at 10 MeV were obtained by combining the data measured by both normal and abnormal TOF spectrometers and a good agreement between measurement and calculation was achieved

Pre-equilibrium effects in (n,2n) cross sections at 14.5 MeV

International Nuclear Information System (INIS)

Gupta, S.K.; Chatterjee, Ambar

The Griffin-Williams exciton model is used to calculate the pre-equilibrium contribution to the (n,2n) reaction around 14.5 MeV neutron energy for nuclei throughout the periodic table. The experimental cross sections for 60< A<209 are explained with an r.m.s. deviation of 0.31 by including a statistical evaporation and a pre-equilibrium component taking into account the competing proton emission. For A<60 the data is not reproduced very well. (auth.)

Neutron radiative capture by the 241Am nucleus in the energy range 1 keV-20 MeV

International Nuclear Information System (INIS)

Zolotarev, K.I.; Ignatyuk, A.V.; Tolstikov, V.A.; Tertychnyj, G.Ya.

1998-01-01

Production of high actinides leads to many technological problems in the nuclear power. The 241 Am(n,γ) 242 Am reaction is one of the sources of high actinide buildup. So a knowledge of the radiative capture cross-section of 241 Am for neutron energies up to 20 MeV is of considerable important for present day fission reactors and future advanced reactors. The main goal of this paper is the evaluation of the excitation function for the reaction 241 Am(n,γ) 242 Am in the energy range 1 keV-20 MeV. The evaluation was done on the basis of analysed experimental data, data from theoretical model calculations and systematic predictions for 14.5 MeV and 20 MeV. Data from the present evaluation are compared with the cross-section values given in the evaluations carried out earlier. (author)

Investigation of Response of Several Neutron Surveymeters by a DT Neutron Generator

International Nuclear Information System (INIS)

Kim, Sang In; Jang, In Su; Kim, Jang Lyul; Lee, Jung IL; Kim, Bong Hwan

2012-01-01

Several neutron measuring devices were tested under the neutron fields characterized with two distinct kinds of thermal and fast neutron spectrum. These neutron fields were constructed by the mixing of both thermal neutron fields and fast neutron fields. The thermal neutron field was constructed using by a graphite pile with eight AmBe neutron sources. The fast neutron field of 14 MeV was made by a DT neutron generator. In order to change the fraction of fast neutron fluence rate in each neutron fields, a neutron generator was placed in the thermal neutron field at 50 cm and 150 cm from the reference position. The polyethylene neutron collimator was used to make moderated 14 MeV neutron field. These neutron spectra were measured by using a Bonner sphere system with an LiI scintillator, and dosimetric quantities delivered to neutron surveymeters were determined from these measurement results.

Determination of the level of some heavy metals in wastewater of Oued Fez by 14 MeV neutron activation analysis

International Nuclear Information System (INIS)

Zaoui, H.; Hamedoun, M.; Chaqroune, A.; Chouak, A.; Lfred, M.; Senhou, A.

2001-01-01

14 MeV neutron activation analysis has been tested for samples of sediments and residues, which were collected along the water discharge of Oued Fez. Analyses of the whole sample as well as the fine fraction of the samples were carried put; the elements that could be detected with good statistics were Fe, Al, Si, Cr, Mg, Rb, Ti, Cl, Na, Ca and Sr and those with low statistics were Ba, Zn and La; however the results show that the most of concentrations obtained are close to those generally observed in downstream water of Oued Fez which would be the most important source of metals releases in Sebou basin river. Physico-chemical analysis was used to determine the indicator parameters of water pollution. They showed that the norms indicated by the World Health Organization (WHO) are largely exceeded. 2 figs., 4 tabs.,12 refs. (au)

EXPERIMENTAL ANALYSES OF SPALLATION NEUTRONS GENERATED BY 100 MEV PROTONS AT THE KYOTO UNIVERSITY CRITICAL ASSEMBLY

Directory of Open Access Journals (Sweden)

CHEOL HO PYEON

2013-02-01

Full Text Available Neutron spectrum analyses of spallation neutrons are conducted in the accelerator-driven system (ADS facility at the Kyoto University Critical Assembly (KUCA. High-energy protons (100 MeV obtained from the fixed field alternating gradient accelerator are injected onto a tungsten target, whereby the spallation neutrons are generated. For neutronic characteristics of spallation neutrons, the reaction rates and the continuous energy distribution of spallation neutrons are measured by the foil activation method and by an organic liquid scintillator, respectively. Numerical calculations are executed by MCNPX with JENDL/HE-2007 and ENDF/B-VI libraries to evaluate the reaction rates of activation foils (bismuth and indium set at the target and the continuous energy distribution of spallation neutrons set in front of the target. For the reaction rates by the foil activation method, the C/E values between the experiments and the calculations are found around a relative difference of 10%, except for some reactions. For continuous energy distribution by the organic liquid scintillator, the spallation neutrons are observed up to 45 MeV. From these results, the neutron spectrum information on the spallation neutrons generated at the target are attained successfully in injecting 100 MeV protons onto the tungsten target.

76 FR 53531 - Environmental Impact Statement: Hancock County, MS

Science.gov (United States)

2011-08-26

...)] Environmental Impact Statement: Hancock County, MS AGENCY: Federal Highway Administration (FHWA), Department Of... that an environmental impact statement will be prepared for a proposed highway project in Hancock... an Environmental Impact Statement (EIS) for the proposed widening and/or realignment of State Route...

The Efficiency of the BC-720 Scintillator in a High-Energy (20--800 MeV) Accelerator Neutron Field

Energy Technology Data Exchange (ETDEWEB)

Miles, Leslie H. [Univ. of Missouri, Columbia, MO (United States)

2005-12-01

High-energy neutron doses (>20 MeV) are of little importance to most radiation workers. However, space and flight crews, and people working around medical and scientific accelerators receive over half of their radiation dose from high-energy neutrons. Unfortunately, neutrons are difficult to measure, and no suitable dosimetry has yet been developed to measure this radiation. In this paper, basic high-energy neutron interactions, characteristics of high-energy neutron environments, present neutron dosimetry, and quantities used in neutron dosimetry are discussed before looking into the potential of the BC-720 scintillator to improve dosimetry. This research utilized 800 MeV protons impinging upon the WNR Facility spallation neutron source at Los Alamos National Laboratory. Time-of-flight methods and a U-238 Fission Chamber were used to aid evaluation of the efficiency of the BC-720. Results showed that the efficiency is finite over the 20–650 MeV energy region studied, although it decreases by a factor of ten between 40 and 100 MeV. This limits the use of this dosimeter to measure doses at sitespecific locations. It also encourages modifications to use this dosimeter for any unknown neutron field. As such, this dosimeter has the potential for a small, lightweight, real-time dose measurement, which could impact neutron dosimetry in all high-energy neutron environments.

Cross-sections for some millisecond beta activities. [14. 7 MeV

Energy Technology Data Exchange (ETDEWEB)

Garg, K C; Khurana, C S [Punjabi Univ., Patiala (India). Dept. of Physics

1979-06-01

An on-line irradiation system involving pulsed beam technique has been developed to handle the millisecond isomers produced in nuclear reactions with 14.7 MeV neutrons. The system originally used to measure the half-lives of a number of millisecond gamma-active isomers has been extended to handle the millisecond pure beta-activities produced in nuclear reactions. An end-window type GM counter has been employed to measure the produced beta activities of /sup 6/He and /sup 9/Li in /sup 7/ /sup 6/Li((n,d))/sup 6/He, /sup 9/Be(n,..cap alpha..)/sup 6/He and /sup 9/Be(n,p)/sup 9/Li reactions.

Neutronics comparisons of d-Li and t-H2O neutron sources

International Nuclear Information System (INIS)

Doran, D.G.; Cierjacks, S.; Mann, F.M.; Greenwood, L.R.; Daum, E.

1995-01-01

Calculations were performed to compare the neutronics of two neutron source concepts which are candidates for an international fusion materials irradiation facility (IFMIF). One concept, d-Li, produces neutrons by stopping 35 MeV deuterons in a flowing lithium target. Criticism of this concept because of the high energy tail above 14 MeV gave rise to the t-H 2 O concept proposed by Cierjacks. It would generate neutrons below 14.6 MeV ( 2 O. Test volumes that met certain damage parameter criteria were estimated. Because of the softer spectra and somewhat lower yields for t-H 2 O, the d-Li concept was found to have a test volume advantage of a factor of 2 or more, depending on the material to be irradiated. ((orig.))

Determination of nitrogen in food stuffs using 14-MeV neutrons

International Nuclear Information System (INIS)

Shaddad, I.; Habbani, F.

1994-03-01

The neutron activation method was used for the determination of nitrogen in local food stuffs ( sorghum, grains, beans, nuts, wheat and sesame ). The 14 N(n,2n) 13 N reaction was used in this analysis. The protein content obtained ranged from 8% to 50%. The results of these measurements were compared with others obtained for the same samples using Kjeldahl chemical method. The comparison showed that the two measurements were in good agreement. An effort was also made to optimise the method with regard to sample irradiation and measurement acquisition times. (author). tabs

Measurement of prompt neutron spectra from the "2"3"9Pu(n, f ) fission reaction for incident neutron energies from 1 to 200 MeV

International Nuclear Information System (INIS)

Chatillon, A.; Belier, G.; Granier, T.; Laurent, B.; Morillon, B.; Taieb, J.; Haight, R.C.; Devlin, M.; Nelson, R.O.; Noda, R.S.; O'Donnell, J.M.

2014-01-01

Prompt fission neutron spectra in the neutron-induced fission of "2"3"9Pu have been measured for incident neutron energies from 1 to 200 MeV at the Los Alamos Neutron Science Center. Mean energies deduced from the prompt fission neutron spectra (PFNS) lead to the observation of the opening of the second chance fission at 7 MeV and to indications for the openings of fission channels of third and fourth chances. Moreover, the general trend of the measured PFNS is well reproduced by the different models. The comparison between data and models presents, however, two discrepancies. First, the prompt neutron mean energy seems constant for neutron energy, at least up to 7 MeV, whereas in the theoretical calculations it is continuously increasing. Second, data disagree with models on the shape of the high energy part of the PFNS, where our data suggest a softer spectrum than the predictions. (authors)

Neutron-proton elastic scattering between 200 and 500 MeV

International Nuclear Information System (INIS)

Clough, A.S.; Gibson, D.R.; Axen, D.

1979-01-01

Measurements over an extensive angular range of the Dsub(t) and P parameters in free neutron-proton elastic scattering at laboratory energies of 220, 325, 425 and 495 MeV are reported. Experimental and analytical details are given. (author)

Energy dependence of fission product yields from 235U, 238U, and 239Pu with monoenergetic neutrons between thermal and 14.8 MeV

Science.gov (United States)

Gooden, Matthew; Arnold, Charles; Bhike, Megha; Bredeweg, Todd; Fowler, Malcolm; Krishichayan; Tonchev, Anton; Tornow, Werner; Stoyer, Mark; Vieira, David; Wilhelmy, Jerry

2017-09-01

Under a joint collaboration between TUNL-LANL-LLNL, a set of absolute fission product yield measurements has been performed. The energy dependence of a number of cumulative fission product yields (FPY) have been measured using quasi-monoenergetic neutron beams for three actinide targets, 235U, 238U and 239Pu, between 0.5 and 14.8 MeV. The FPYs were measured by a combination of fission counting using specially designed dual-fission chambers and γ-ray counting. Each dual-fission chamber is a back-to-back ionization chamber encasing an activation target in the center with thin deposits of the same target isotope in each chamber. This method allows for the direct measurement of the total number of fissions in the activation target with no reference to the fission cross-section, thus reducing uncertainties. γ-ray counting of the activation target was performed on well-shielded HPGe detectors over a period of two months post irradiation to properly identify fission products. Reported are absolute cumulative fission product yields for incident neutron energies of 0.5, 1.37, 2.4, 3.6, 4.6, 5.5, 7.5, 8.9 and 14.8 MeV. Preliminary results from thermal irradiations at the MIT research reactor will also be presented and compared to present data and evaluations. This work was performed under the auspices of the U.S. Department of Energy by Los Alamos National Security, LLC under contract DE-AC52-06NA25396, Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344 and by Duke University and Triangle Universities Nuclear Laboratory through NNSA Stewardship Science Academic Alliance grant No. DE-FG52-09NA29465, DE-FG52-09NA29448 and Office of Nuclear Physics Grant No. DE-FG02-97ER41033.

Measurement of secondary gamma-ray skyshine and groundshine from intense 14 MeV neutron source facility

Energy Technology Data Exchange (ETDEWEB)

Yoshida, Shigeo; Morotomi, Ryutaro; Kondo, Tetsuo; Murata, Isao; Takahashi, Akito [Osaka Univ., Suita (Japan). Dept. of Nuclear Engineering

2000-03-01

Secondary gamma-ray skyshine and groundshine, including the direct contribution from the facility building, have been measured with an Hp-Ge detector and an NaI(Tl) detector at the Intense 14 MeV Neutron Source Facility OKTAVIAN of Osaka University, Japan. The mechanism of secondary gamma-rays propagation were analyzed with the measured spectrum with the Hp-Ge detector. The contribution of the skyshine was shown to be a continuum spectrum that was composed of mainly Compton scattered high energy secondary gamma-rays generated in the facility building created by (n, {gamma}) reaction. The contribution of the groundshine considerably contained secondary gamma-rays generated by {sup nat}Si (n, {gamma}) reaction in soil, including the albedo contribution from the ground. And the total contribution contained capture gamma-rays from iron (Fe) and other nuclides. The measurements with the NaI(Tl) detector as well as the Hp-Ge detector were carried out to investigate the dependence of gamma-ray dose as a function of distance from the neutron source up to hundreds meters. Consequently, it was found that the dependence could be fitted with the function of const.{center_dot}exp(-r/{lambda})/r{sup n}, where n values were around 2 except for the skyshine (n {approx} 1). It was thus indicated that the contribution of the skyshine could be propagated farther downfield than the direct contribution from the facility. The measured ratios of the three contributions (skyshine, groundshine, and direct contributions) and the distance dependence in each path were shown to be in good agreement with calculated results by the Monte Carlo transport code MCNP-4A. And the total contributions for the two detectors of NaI(Tl) and Hp-Ge agree excellently with each other. (author)

Measurements of the {sup 40}Ar(n, γ){sup 41}Ar radiative-capture cross section between 0.4 and 14.8 MeV

Energy Technology Data Exchange (ETDEWEB)

Bhike, Megha, E-mail: megha@tunl.duke.edu [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Fallin, B.; Tornow, W. [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States)

2014-09-07

The {sup 40}Ar(n, γ){sup 41}Ar neutron capture cross section has been measured between 0.4 and 14.8 MeV neutron energy using the activation technique. The data are important for estimating backgrounds in argon-based neutrino and dark-matter detectors and in the neutrino-less double-beta decay search GERDA, which uses liquid argon as cooling and shielding medium. For the first time the {sup 40}Ar(n, γ){sup 41}Ar cross section has been measured for neutron energies above 1 MeV. Our results are compared to the evaluation ENDF/B-VII.1 and the calculated prediction TENDL-2013. The latter agrees very well with the present results.

Neutron-deuteron analyzing power data at En=22.5 MeV

Science.gov (United States)

Weisel, G. J.; Tornow, W.; Crowell, A. S.; Esterline, J. H.; Hale, G. M.; Howell, C. R.; O'Malley, P. D.; Tompkins, J. R.; Witała, H.

2014-05-01

We present measurements of n-d analyzing power, Ay(θ), at En=22.5 MeV. The experiment uses a shielded neutron source which produced polarized neutrons via the 2H(d⃗,n⃗)3He reaction. It also uses a deuterated liquid-scintillator center detector and six pairs of liquid-scintillator neutron side detectors. Elastic neutron scattering events are identified by using time-of-flight techniques and by setting a window in the center detector pulse-height spectrum. The beam polarization is monitored by using a high-pressure helium gas cell and an additional pair of liquid-scintillator side detectors. The n-d Ay(θ) data were corrected for finite-geometry and multiple-scattering effects using a Monte Carlo simulation of the experiment. The 22.5-MeV data demonstrate that the three-nucleon analyzing power puzzle also exists at this energy. They show a significant discrepancy with predictions of high-precision nucleon-nucleon potentials alone or combined with Tucscon-Melbourne or Urbana IX three-nucleon forces, as well as currently available effective-field theory based potentials of next-to-next-to-next-to-leading order.

The fission cross section ratios and error analysis for ten thorium, uranium, neptunium and plutonium isotopes at 14.74 MeV neutron energy

International Nuclear Information System (INIS)

Meadows, J.W.

1987-03-01

The error information from the recent measurements of the fission cross section ratios of nine isotopes, 230 Th, 232 Th, 233 U, 234 U, 236 U, 238 U, 237 Np, 239 Pu, and 242 Pu, relative to 235 U at 14.74 MeV neutron energy was used to calculate their correlations. The remaining 36 non-trivial and non-reciprocal cross section ratios and their errors were determined and compared to evaluated (ENDF/B-V) values. There are serious differences but it was concluded that the reduction of three of the evaluated cross sections would remove most of them. The cross sections to be reduced are 230 Th - 13%, 237 Np - 9.6% and 239 Pu - 7.6%. 5 refs., 6 tabs

A simple neutron-gamma discriminating system

International Nuclear Information System (INIS)

Liu Zhongming; Xing Shilin; Wang Zhongmin

1986-01-01

A simple neutron-gamma discriminating system is described. A detector and a pulse shape discriminator are suitable for the neutron-gamma discriminating system. The influence of the constant fraction discriminator threshold energy on the neutron-gamma resolution properties is shown. The neutron-gamma timing distributions from an 241 Am-Be source, 2.5 MeV neutron beam and 14 MeV neutron beam are presented

Charged-particle magnetic-quadrupole spectrometer for neutron induced reactions

International Nuclear Information System (INIS)

Haight, R.C.; Grimes, S.M.; Tuckey, B.J.; Anderson, J.D.

1975-01-01

A spectrometer has been developed for measuring the charged particle production cross sections and spectra in neutron-induced reactions. The spectrometer consists of a magnetic quadrupole doublet which focuses the charged particles onto a silicon surface barrier detector telescope which is 2 meters or more from the irradiated sample. Collimators, shielding, and the large source-to-detector distance reduce the background enough to use the spectrometer with a 14-MeV neutron source producing 4 . 10 12 n/s. The spectrometer has been used in investigations of proton, deuteron, and alpha particle production by 14-MeV neutrons incident on various materials. Protons with energies as low as 1.1 MeV have been measured. The good resolution of the detectors has also made possible an improved measurement of the neutron- neutron scattering length from the 0 0 proton spectrum from deuteron breakup by 14-MeV neutrons

Simulation study of neutron production in thick beryllium targets by 35 MeV and 50.5 MeV proton beams

Science.gov (United States)

Shin, Jae Won; Park, Tae-Sun

2017-09-01

A data-driven nuclear model dedicated to an accurate description of neutron productions in beryllium targets bombarded by proton beams is developed as a custom development that can be used as an add-on to GEANT4 code. The developed model, G4Data(Endf7.1), takes as inputs the total and differential cross section data of ENDF/B-VII.1 for not only the charge-exchange 9Be(p,n)9B reaction which produces discrete neutrons but also the nuclear reactions relevant for the production of continuum neutrons such as 9Be(p,pn)8Be and 9Be(p,n α) 5Li . In our benchmarking simulations for two experiments with 35 MeV and 50.5 MeV proton beams impinged on 1.16 and 1.05 cm thick beryllium targets, respectively, we find that the G4Data(Endf7.1) model can reproduce both the total amounts and the spectral shapes of the measured neutron yield data in a satisfactory manner, while all the considered hadronic models of GEANT4 cannot.

Beam dynamics study of a 30 MeV electron linear accelerator to drive a neutron source

Science.gov (United States)

Kumar, Sandeep; Yang, Haeryong; Kang, Heung-Sik

2014-02-01

An experimental neutron facility based on 32 MeV/18.47 kW electron linac has been studied by means of PARMELA simulation code. Beam dynamics study for a traveling wave constant gradient electron accelerator is carried out to reach the preferential operation parameters (E = 30 MeV, P = 18 kW, dE/E E-gun, pre-buncher, buncher, and 2 accelerating columns. A disk-loaded, on-axis-coupled, 2π/3-mode type accelerating rf cavity is considered for this linac. After numerous optimizations of linac parameters, 32 MeV beam energy is obtained at the end of the linac. As high electron energy is required to produce acceptable neutron flux. The final neutron flux is estimated to be 5 × 1011 n/cm2/s/mA. Future development will be the real design of a 30 MeV electron linac based on S band traveling wave.

Proposed 14-MeV neutron spectrometer system for jet

International Nuclear Information System (INIS)

Elevant, T.

1983-09-01

In order to cover a broad range of neutron spectra and fluxes during D-T operation in JET we propose the use of two different detector techniques neutron induced reactions in a silicon surface barrier detector and neutron-proton elastic scattering in a liquid scintillator. Experimental investigations of 28 Si(n,α) 25 Mg reactions have resulted in resolutions of ΔE(FWHM)/E=0.02 with intrinsic efficiency equal to 10 -4 and a maximum useful countrate equal to 1600 c.p.s. However, due to overlap of adjacent peaks, caused by excited states of 25 Mg, this spectrometer has an operation range limited to FWHM/E=0.04. For broader neutron distributions we propose the use of a conventional liquid scintillator system with a light guide, photomultiplier tube and modified conventional electronics. Experiments have demonstrated a resolution equal to 0.05 and a n/γ separation better than 90percent at total countrates equal to 2times10 5 c.p.s. (author)

Neutron-transmuted carbon-14 in neutron-irradiated GaN: Compensation of DX-like center

International Nuclear Information System (INIS)

Ida, T.; Oga, T.; Kuriyama, K.; Kushida, K.; Xu, Q.; Fukutani, S.

2013-01-01

The transmuted-C related luminescence and net carrier concentration are studied by combining photoluminescence, liquid scintillation, and Raman scattering. GaN single crystal films grown by metalorganic-vapor-phase epitaxy are irradiated with fast and thermal neutrons at fluxes of 3.9 × 10 13 cm −2 s −1 and 8.15 × 10 13 cm −2 s −1 , respectively. Irradiation time is 48 hours. The calculated 72 Ge and 14 C concentrations are 1.24 × 10 18 cm −3 and 1.13 × 10 18 cm −3 , respectively. The transmuted 14 C is detected by the liquid scintillation method to survey β-rays emitted in the process of 14 C decays from 14 N. Tritium ( 3 H) is also emitted by a (n,t) reaction of 14 N due to the neutron irradiation above 4.5 MeV. Photoluminescence relating to C, DX-like center of Ge and yellow luminescence band are observed in 1000 °C annealed NTD-GaN. The free electron concentration estimated from Raman scattering is 4.97 × 10 17 cm −3 . This value is lower than that from the transmuted Ge concentration, suggesting the compensation due to the transmuted 14 C acceptors

Tooth enamel dosimetric response to 2.8 MeV neutrons

Science.gov (United States)

Fattibene, P.; Angelone, M.; Pillon, M.; De Coste, V.

2003-03-01

Tooth enamel dosimetry, based on electron paramagnetic resonance (EPR) spectroscopy, is recognized as a powerful method for individual retrospective dose assessment. The method is mainly used for individual dose reconstruction in the epidemiological studies aimed at the radiation risk analysis. The study of the sensitivity of tooth enamel as a function of radiation quality is one of the main goals of the research in this field. In the present work, tooth enamel dose response in a monoenergetic neutron flux of 2.8 MeV, generated by the D-D reaction, was studied for in air and in phantom irradiations of enamel samples and of whole teeth. EPR measurements were complemented by Monte Carlo calculation and by gamma dose discrimination obtained with thermoluminescent and Geiger-Muller tube measurements. The 2.8 MeV neutrons to 60Co relative sensitivity was 0.33±0.08.

Tooth enamel dosimetric response to 2.8 MeV neutrons

International Nuclear Information System (INIS)

Fattibene, P.; Angelone, M.; Pillon, M.; De Coste, V.

2003-01-01

Tooth enamel dosimetry, based on electron paramagnetic resonance (EPR) spectroscopy, is recognized as a powerful method for individual retrospective dose assessment. The method is mainly used for individual dose reconstruction in the epidemiological studies aimed at the radiation risk analysis. The study of the sensitivity of tooth enamel as a function of radiation quality is one of the main goals of the research in this field. In the present work, tooth enamel dose response in a monoenergetic neutron flux of 2.8 MeV, generated by the D-D reaction, was studied for in air and in phantom irradiations of enamel samples and of whole teeth. EPR measurements were complemented by Monte Carlo calculation and by gamma dose discrimination obtained with thermoluminescent and Geiger-Muller tube measurements. The 2.8 MeV neutrons to 60 Co relative sensitivity was 0.33±0.08

MODELING THE RADIATION SHIELDING OF BORON NEUTRON CAPTURE THERAPY BASED ON 2.4 MEV D-D NEUTRON GENERATOR FACILITY

Directory of Open Access Journals (Sweden)

Muhammad Mu’Alim

2018-01-01

PEMODELAN PERISAI RADIASI PADA FASILITAS BORON NEUTRON CAPTURE THERAPY BERBASIS GENERATOR NEUTRON D-D 2,4 MeV. Telah dimodelkan perisai radiasi pada fasilitas Boron Neutron Capture Therapy (BNCT berbasis reaksi D-D pada Neutron Generator 2,4 MeV dengan Beam Shaping Assembly (BSA yang telah didesain sebelumnya. Pemodelan ini dilakukan untuk memperoleh suatu desain perisai radiasi untuk fasilitas BNCT berbasis generator neutron 2,4 MeV. Pemodelan dilakukan dengan cara memvariasikan bahan dan ketebalan perisasi radiasi. Bahan yang dipilih adalah beton barit, parafin, polietilen terborasi dan timbal. Perhitungan dilakukan menggunakan program MCNPX dengan tally F4 untuk menentukan laju dosis yang keluar dari perisai radiasi. Desain periasi radiasi dinyatakan optimal jika radiasi yang dihasilkan diluar perisai radiasi tidak melebihi Nilai Batas Dosis (NBD yang telah ditentukan oleh BAPETEN. Hasilnya, diperoleh suatu desain perisai radiasi menggunakan lapisan utama beton barit setebal 100 cm yang mengelilingi ruangan 100 cm x 100 cm x 166,4 cm dan polietilen terborasi 40 cm yang mengelilingi bahan beton barit. Kemudian ditambahkan beton barit 10 cm dan polietilen terborasi 10 cm untuk mengurangi radiasi primer yang lurus dari BSA setelah keluar dari lapisan utama. Laju dosis terbesar adalah 4,58 μSv·jam-1 pada sel 227 dan laju dosis rata-rata yang dihasilkan adalah sebesar 0,65 µSv·jam-1. Nilai laju dosis tersebut masih dibawah ambang batas NBD yang diperbolehkan oleh BAPETEN untuk pekerja radiasi. Kata kunci: Perisai radiasi, tally, laju dosis radiasi, BSA, BNCT

Measurements of fission product yield in the neutron-induced fission of 238U with average energies of 9.35 MeV and 12.52 MeV

Science.gov (United States)

Mukerji, Sadhana; Krishnani, Pritam Das; Shivashankar, Byrapura Siddaramaiah; Mulik, Vikas Kaluram; Suryanarayana, Saraswatula Venkat; Naik, Haladhara; Goswami, Ashok

2014-07-01

The yields of various fission products in the neutron-induced fission of 238U with the flux-weightedaveraged neutron energies of 9.35 MeV and 12.52 MeV were determined by using an off-line gammaray spectroscopic technique. The neutrons were generated using the 7Li(p, n) reaction at Bhabha Atomic Research Centre-Tata Institute of Fundamental Research Pelletron facility, Mumbai. The gamma- ray activities of the fission products were counted in a highly-shielded HPGe detector over a period of several weeks to identify the decaying fission products. At both the neutron energies, the fission-yield values are reported for twelve fission product. The results obtained from the present work have been compared with the similar data for mono-energetic neutrons of comparable energy from the literature and are found to be in good agreement. The peak-to-valley (P/V) ratios were calculated from the fission-yield data and were found to decreases for neutron energy from 9.35 to 12.52 MeV, which indicates the role of excitation energy. The effect of the nuclear structure on the fission product-yield is discussed.

Neutron-induced fission cross sections of uraniums up to 40 MeV

Energy Technology Data Exchange (ETDEWEB)

Maslov, V.M. [Radiation Physics and Chemistry Problems Inst., Minsk-Sosny (Belarus); Hasegawa, A.

1998-11-01

Statistical theory of nuclear reactions, well-proved below 20 MeV, is applied for {sup 235}U and {sup 238}U fission data analysis up to {approx}40 MeV. It is shown that measured data could be reproduced. Chance structure of measured fission cross section is provided, it`s validity is supported by description of data for competing (n,xn)-reactions. Role of fissility of target nucleus is addressed. It seems that gap in incident neutron energy interval of 20 MeV - 50 MeV, below which evaluation approaches are well-developed, and above which simplified statistical approaches are valid, could be covered. (author)

Neutron spectra characteristics for the intense neutron source, INS

International Nuclear Information System (INIS)

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

1977-01-01

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

Neutron total, scattering and inelastic gamma-ray cross sections of yttrium at few MeV energies

International Nuclear Information System (INIS)

Budtz-Joergensen, C.; Guenther, P.; Smith, A.; Whalen, J.; McMurray, W.R.; Renan, M.J.; Heerden, I.J. van

1984-01-01

Neutron total, scattering and (n; n', γ) cross sections of elemental yttrium ( 89 Y) were measured in the few-MeV region. The neutron total-cross-section measurements were made with broad resolutions from approx.=0.5 to 4.2 MeV in steps of < or approx.0.1 MeV. Neutron elastic- and inelastic-scattering cross sections were measured from approx.=1.5 to 4.0 MeV, at incident-neutron energy intervals of approx.=50 keV and at ten or more scattering angles distributed between 20 and 160 degrees using neutron detection. Inelastic-scattering cross sections were also determined using the (n; n', γ) reaction at incident energies from 1.6 to 3.8 MeV at intervals of 0.1 MeV. Gamma-rays and/or inelastically-scattered neutrons were observed corresponding to the excitation of levels at: 909.0+-0.5, 1,507.4+-0.3, 1,744.5+-0.3, 2,222.6+-0.5, 2,530+-0.8, 2,566.4+-1.0, 2,622.5+-1.0, 2,871.9+-1.5, 2,880.6+-2.0, 3,067.0+-2.0, 3,107.0+-2.0, 3,140.0+-2.0, 3,410.0+-2.0, 3,450.0+-2.0, 3,504.0+-1.5, 3,514.0+-2.0, 3,556.0+-2.0, 3,619.0+-3.0, 3,629.0+-3.0 and 3,715.0+-3.0 keV. The experimental results are discussed in terms of the spherical-optical-statistical, coupled-channels, and core-coupling models, and in the context of previously reported excited-level structure. (orig.)

Review of RBE values of 15 MeV neutrons for effects on normal tissues

NARCIS (Netherlands)

Broerse, J.J.

1974-01-01

Values of the relative biological effectiveness (RBE) of fast neutrons for effect on normal tissue depend not only on the neutron energy and the dose, but also on the type of tissue irradiated. Values of the RBE of 15 MeV neutrons are reviewed for rapidly proliferating rodent tissue, such as mouse

Neutron kinetics in moderators and SNM detection through epithermal-neutron-induced fissions

Energy Technology Data Exchange (ETDEWEB)

Gozani, Tsahi, E-mail: tgmaven@gmail.com [1050 Harriet St., Palo Alto, CA 94301 (United States); King, Michael J. [Rapiscan Laboratories Inc., 520 Almanor Ave., Sunnyvale, CA 94085 (United States)

2016-01-01

Extension of the well-established Differential Die Away Analysis (DDAA) into a faster time domain, where more penetrating epithermal neutrons induce fissions, is proposed and demonstrated via simulations and experiments. In the proposed method the fissions stimulated by thermal, epithermal and even higher-energy neutrons are measured after injection of a narrow pulse of high-energy 14 MeV (d,T) or 2.5 MeV (d,D) source neutrons, appropriately moderated. The ability to measure these fissions stems from the inherent correlation of neutron energy and time (“E–T” correlation) during the process of slowing down of high-energy source neutrons in common moderating materials such as hydrogenous compounds (e.g., polyethylene), heavy water, beryllium and graphite. The kinetic behavior following injection of a delta-function-shaped pulse (in time) of 14 MeV neutrons into such moderators is studied employing MCNPX simulations and, when applicable, some simple “one-group” models. These calculations served as a guide for the design of a source moderator which was used in experiments. Qualitative relationships between slowing-down time after the pulse and the prevailing neutron energy are discussed. A laboratory system consisting of a 14 MeV neutron generator, a polyethylene-reflected Be moderator, a liquid scintillator with pulse-shape discrimination (PSD) and a two-parameter E–T data acquisition system was set up to measure prompt neutron and delayed gamma-ray fission signatures in a 19.5% enriched LEU sample. The measured time behavior of thermal and epithermal neutron fission signals agreed well with the detailed simulations. The laboratory system can readily be redesigned and deployed as a mobile inspection system for SNM in, e.g., cars and vans. A strong pulsed neutron generator with narrow pulse (<75 ns) at a reasonably high pulse frequency could make the high-energy neutron induced fission modality a realizable SNM detection technique.

Inelastic scattering of 1-2.5 MeV neutrons by 235U and 238U nuclei

International Nuclear Information System (INIS)

Kornilov, N.V.; Kagalenko, A.B.; Baryba, V.Ya.; Balitskij, A.V.; Androsenko, A.A.; Androsenko, P.A.

1993-07-01

The inelastic scattering cross-sections of 1-2.5 MeV neutrons for 235 U and 238 0 nuclei were measured. A detailed description is given of the data processing procedures used, and the methods for determining the neutron flux in the sample. The Monte Carlo method was used to calculate the corrections for multiple neutron scattering and neutron flux attenuation in the sample. Pursuant to an analysis of the fission neutron spectra, we concluded that the systematic error level of the results is ± 3.27%. The results of these cross-section and spectrum measurements for inelastically scattered neutrons are compared with results from other sources and existing evaluations, the possible causes of the divergences for neutrons with an energy level of less than 1 MeV are analysed, and suggestions are put forward for future research work. (author)

Study on the energy response to neutrons for a new scintillating-fiber-array neutron detector

CERN Document Server

Zhang Qi; Wang Qun; Xie Zhong Shen

2003-01-01

The energy response of a new scintillating-fiber-array neutron detector to neutrons in the energy range 0.01 MeV<=E sub n<=14 MeV was modeled by combining a simplified Monte Carlo model and the MCNP 4b code. In order to test the model and get the absolute sensitivity of the detector to neutrons, one experiment was carried out for 2.5 and 14 MeV neutrons from T(p,n) sup 3 He and T(d,n) sup 4 He reactions at the Neutron Generator Laboratory at the Institute of Modern Physics, the Chinese Academy of Science. The absolute neutron fluence was obtained with a relative standard uncertainty 4.5% or 2.0% by monitoring the associated protons or sup 4 He particles, respectively. Another experiment was carried out for 0.5, 1.0, 1.5, 2.0, 2.5 MeV neutrons from T(p,n) sup 3 He reaction, and for 3.28, 3.50, 4.83, 5.74 MeV neutrons from D(d,n) sup 3 He reaction on the Model 5SDH-2 accelerator at China Institute of Atomic Energy. The absolute neutron fluence was obtained with a relative standard uncertainty 5.0% by usin...

Evaluating the 239Pu Prompt Fission Neutron Spectrum Induced by Thermal to 30 MeV Neutrons

Directory of Open Access Journals (Sweden)

Neudecker D.

2016-01-01

Full Text Available We present a new evaluation of the 239Pu prompt fission neutron spectrum (PFNS induced by thermal to 30 MeV neutrons. Compared to the ENDF/B-VII.1 evaluation, this one includes recently published experimental data as well as an improved and extended model description to predict PFNS. For instance, the pre-equilibrium neutron emission component to the PFNS is considered and the incident energy dependence of model parameters is parametrized more realistically. Experimental and model parameter uncertainties and covariances are estimated in detail. Also, evaluated covariances are provided between all PFNS at different incident neutron energies. Selected evaluation results and first benchmark calculations using this evaluation are briefly discussed.

Track-etch dosemeter response to neutrons up to 300 MeV

International Nuclear Information System (INIS)

Devine, R.T.; Walker, S.; Staples, P.; Duran, M.; Mundis, R.; Miller, J.

1996-01-01

Electro-chemical and chemical track-etch dosemeters were obtained from commercial suppliers and exposed to neutrons produced at the LANTF WNR white neutron source at 15 degree with no shielding and filtered by polyethylene blocks of 2.5, 5.1, 10.2, 20.3 and 40.6 cin thickness. The neutron spectrum was determined using calculations. Mean energies from 28 to 300 MeV were produced. Dose was calculated from the NCRP-38 flux-to-dose conversion. The results are compared with NTA film which was exposed in the same configuration. The response of track etch dosimeters was found to reach a minimum and then rise as the average neutron energy increased. The response of the NTA film increased as the neutron energy increased

Production of neutron-rich nuclei in fission induced by neutrons generated by the p+ sup 1 sup 3 C reaction at 55 MeV

CERN Document Server

Stroe, L; Andrighetto, A; Tecchio, L B; Dendooven, P; Huikari, J; Pentillä, H; Peraejaervi, K; Wang, Y

2003-01-01

Cross-sections for the production of neutron-rich nuclei obtained by neutron-induced fission of natural uranium have been measured. The neutrons were generated by bombarding a sup 1 sup 3 C target with 55 MeV protons. The results, position of the maximum in the (Z, A)-plane, width and magnitude, are very comparable with those where the neutrons are generated by bombardment of natural sup 1 sup 2 C graphite with 50 MeV deuterons. Depending on the geometry of the converter/target assembly the isotope yields, however, are a factor of 2-3 lower due to less efficient production of neutrons per primary projectile, especially at small forward angles. (orig.)

The fission cross section ratios and error analysis for ten thorium, uranium, neptunium and plutonium isotopes at 14. 74 MeV neutron energy

Energy Technology Data Exchange (ETDEWEB)

Meadows, J.W.

1987-03-01

The error information from the recent measurements of the fission cross section ratios of nine isotopes, /sup 230/Th, /sup 232/Th, /sup 233/U, /sup 234/U, /sup 236/U, /sup 238/U, /sup 237/Np, /sup 239/Pu, and /sup 242/Pu, relative to /sup 235/U at 14.74 MeV neutron energy was used to calculate their correlations. The remaining 36 non-trivial and non-reciprocal cross section ratios and their errors were determined and compared to evaluated (ENDF/B-V) values. There are serious differences but it was concluded that the reduction of three of the evaluated cross sections would remove most of them. The cross sections to be reduced are /sup 230/Th - 13%, /sup 237/Np - 9.6% and /sup 239/Pu - 7.6%. 5 refs., 6 tabs.

Performance analysis of fusion nuclear-data benchmark experiments for light to heavy materials in MeV energy region with a neutron spectrum shifter

International Nuclear Information System (INIS)

Murata, Isao; Ohta, Masayuki; Miyamaru, Hiroyuki; Kondo, Keitaro; Yoshida, Shigeo; Iida, Toshiyuki; Ochiai, Kentaro; Konno, Chikara

2011-01-01

Nuclear data are indispensable for development of fusion reactor candidate materials. However, benchmarking of the nuclear data in MeV energy region is not yet adequate. In the present study, benchmark performance in the MeV energy region was investigated theoretically for experiments by using a 14 MeV neutron source. We carried out a systematical analysis for light to heavy materials. As a result, the benchmark performance for the neutron spectrum was confirmed to be acceptable, while for gamma-rays it was not sufficiently accurate. Consequently, a spectrum shifter has to be applied. Beryllium had the best performance as a shifter. Moreover, a preliminary examination of whether it is really acceptable that only the spectrum before the last collision is considered in the benchmark performance analysis. It was pointed out that not only the last collision but also earlier collisions should be considered equally in the benchmark performance analysis.

Neutron emission in fission of highly excited californium nuclei (E*=76 MeV)

International Nuclear Information System (INIS)

Blinov, M.V.; Bordyug, V.M.; Kozulin, Eh.M.; Mozhaev, A.N.; Levitovich, M.; Muzychka, Yu.A.; Penionzhkevich, Yu.Eh.; Pustyl'nik, B.I.

1990-01-01

The differential cross sections for neutron production in the fission of highly excited californium nuclei formed in the 238 U+ 12 C (105 MeV) reaction have been measured. From the analysis of the experimental data is follows that the number of pre-fission neutrons substantially exceeds the value obtained in the framework of the standard statistical model. The saddle-to-scission time of the excited nucleus is estimated on the basis of the neutron multiplicity. The dependences of the neutron number and neutron average energies upon the fragment mass are determined

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

International Nuclear Information System (INIS)

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

2010-01-01

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

Measurements of fission product yield in the neutron-induced fission of {sup 238}U with average energies of 9.35 MeV and 12.52 MeV

Energy Technology Data Exchange (ETDEWEB)

Mukerji, Sadhana; Krishnani, Pritam Das; Suryanarayana, Saraswatula Venkat; Naik, Haladhara; Goswami, Ashok [Bhabha Atomic Research Centre, Mumbai (India); Shivashankar, Byrapura Siddaramaiah [Manipal University, Manipal (India); Mulik, Vikas Kaluram [University of Pune, Pune (India)

2014-07-15

The yields of various fission products in the neutron-induced fission of {sup 238}U with the flux-weighted averaged neutron energies of 9.35 MeV and 12.52 MeV were determined by using an off-line gamma ray spectroscopic technique. The neutrons were generated using the {sup 7}Li(p, n) reaction at Bhabha Atomic Research Centre-Tata Institute of Fundamental Research Pelletron facility, Mumbai. The gamma- ray activities of the fission products were counted in a highly-shielded HPGe detector over a period of several weeks to identify the decaying fission products. At both the neutron energies, the fission-yield values are reported for twelve fission product. The results obtained from the present work have been compared with the similar data for mono-energetic neutrons of comparable energy from the literature and are found to be in good agreement. The peak-to-valley (P/V) ratios were calculated from the fission-yield data and were found to decreases for neutron energy from 9.35 to 12.52 MeV, which indicates the role of excitation energy. The effect of the nuclear structure on the fission product-yield is discussed.

Neutron-Neutron effective range from a comparison of n-n and n-p quasi-free scattering at 24 MeV

International Nuclear Information System (INIS)

Witsch, W. von; Gomez Moreno, B.; Rosenstock, W.; Franke, R.; Steinheuer, B.

1980-01-01

Neutron-neutron and neutron-proton quasi-free scattering have been measured at Esub(n) = 24 MeV the d + n reaction to deduce the n-n effective range from a comparison of relative cross sections, reducing considerably experimental as well as theoretical uncertainties. A Monte Carlo analysis with exact three-body calculations yields rsub(nn) = 2.65 +- 0.18 fm. (orig.)

Measurement of neutron-induced fission cross-sections of Th232, U238, U233 and Np237 relative to U235 from 1 MeV to 200 MeV

Energy Technology Data Exchange (ETDEWEB)

Shcherbakov, O.A.; Laptev, A.B.; Petrov, G.A. [Petersburg Nuclear Physics Inst., Gatchina, Leningrad district (Russian Federation); Fomichev, A.V.; Donets, A.Y.; Osetrov, O.I.

1998-11-01

The measurements of neutron-induced cross-section ratios for Th232, U238, U233 and Np237 relative to U235 have been carried out in the energy range from 1 MeV up to 200 MeV using the neutron time-of-flight spectrometer GNEIS based on 1 GeV proton synchrocyclotron. Below 20 MeV, the results of present measurements are roughly in agreement with evaluated data though there are some discrepances to be resolved. (author)

Neutron doses to personnel from a 24 MeV betatron

International Nuclear Information System (INIS)

Beckham, W.A; Entwistle, R.F.

1987-01-01

Neutrons are produced by bombardment of most materials by high-energy photons. Because the x-ray shielding around high-energy x-ray generators may not have been designed with neutrons in mind there may be unexpected contributions to the radiation doses of staff working in the immediate vicinity. Neutron fluxes in the working area close to an Allis-Chalmers 24 MeV betatron have been measured using a lithium-6-loaded scintillator and the dose rates calculated. Hazard of staff has been found to be low; typical dose-equivalent rates in occupied areas range from 0.0042 to 0.012 mrem/hour. The flux of fast neutrons in the treatment room was found to be essentially zero. Measurements of neutron flux may be routinely performed using the scintillation detector (NE 912) described, and could usefully form part of the acceptance protocol for any new accelerator

Utilization of new 150-MeV neutron and proton evaluations in MCNP

International Nuclear Information System (INIS)

Little, R.C.; Frankle, S.C.; Hughes, H.G. III; Prael, R.E.

1997-01-01

MCNP trademark and LAHET trademark are two of the codes included in the LARAMIE (Los Alamos Radiation Modeling Interactive Environment) code system. Both MCNP and LAHET are three-dimensional continuous-energy Monte Carlo radiation transport codes. The capabilities of MCNP and LAHET are currently being merged into one code for the Accelerator Production of Tritium (APT) program at Los Alamos National Laboratory. Concurrently, a significant effort is underway to improve the accuracy of the physics in the merged code. In particular, full nuclear-data evaluations (in ENDF6 format) for many materials of importance to APT are being produced for incident neutrons and protons up to an energy of 150-MeV. After processing, cross-section tables based on these new evaluations will be available for use fin the merged code. In order to utilize these new cross-section tables, significant enhancements are required for the merged code. Neutron cross-section tables for MCNP currently specify emission data for neutrons and photons only; the new evaluations also include complete neutron-induced data for protons, deuterons, tritons, and alphas. In addition, no provision in either MCNP or LAHET currently exists for the use of incident charged-particle tables other than for electrons. To accommodate the new neutron-induced data, it was first necessary to expand the format definition of an MCNP neutron cross-section table. The authors have prepared a 150-MeV neutron cross-section library in this expanded format for 15 nuclides. Modifications to MCNP have been implemented so that this expanded neutron library can be utilized

Quality factor calculations for neutron spectra below 4 MeV

International Nuclear Information System (INIS)

Borak, T.B.; Stinchcomb, T.G.

1979-01-01

A method is described for computing the distribution of absorbed dose, D(L), as a function of linear energy transfer, L, for any neutron spectrum with energies below 4 MeV. The results are used to determine the average quality factor for two distinctly different neutron spectra using the ICRP recommended values of the quality factor, Q(L). A comparison is made between the calculations and measurements of D(L) using a spherical tissue equivalent proportional counter. Heavy ion recoil contributions to the average quality factor are examined in detail. (author)

Study of the response of a silicon detector irradiated with 1 MeV neutrons; Etude de la reponse d`un detecteur Si irradie par des neutrons de 1 MeV

Energy Technology Data Exchange (ETDEWEB)

Roy, P [Montreal Univ., PQ (Canada). Lab. de Physique Nucleaire

1994-12-31

The author studied the response of an n-type silicon detector irradiated with 1 MeV neutrons at fluences ranging from 0.26x10{sup 13} to 11.19x10{sup 13} neutrons/cm{sup 2}. The response of the irradiated detector to {sup 241}Am alpha particles was measured. 13 refs., 7 figs.

Systematics of (n,t) reactions in medium and heavy mass nuclei at 14.6 MeV

International Nuclear Information System (INIS)

Woo, T.T.

1979-01-01

The production cross sections for (n,t) reactions of 14.6-MeV neutrons with isotopes of the natural elements Ca, Ti, Cr, Fe, Ni, Y, Mo, Pd, Cd, Sn, Pb, La, and with the enriched isotopes 86 Sr, 114 Cd, 130 Te, 205 Tl were measured by the activation technique using high-energy resolution gamma-ray spectrometry. The systematics for the (n,t) reactions were investigated as a function of the relative neutron excess. The experimentally determined values of the cross sections are in good agreement with values calculated by an empirical equation. The cross section ratios (n,t) and (n,p) reactions were calculated on the basis of the statistical model

Radionuclide 252Cf neutron source

International Nuclear Information System (INIS)

Kolevatov, Yu.I.; Trykov, L.A.

1979-01-01

Characteristics of radionuclide neutron sourses of 252 Cf base with the activity from 10 6 to 10 9 n/s have been investigated. Energetic distributions of neutrons and gamma-radiation have been presented. The results obtained have been compared with other data available. The hardness parameter of the neutron spectrum for the energy range from 3 to 15 MeV is 1.4 +- 0.02 MeV

A study of the reactions 14C( vector d, dprime)14C and 14C ( vector d, p)15C at 16.0 MeV

International Nuclear Information System (INIS)

Murillo, G.; Sen, S.; Darden, S.E.

1994-01-01

Cross-section and vector-analyzing-power measurements for 14 C(d, d prime) and 14 C(d, p) reactions have been carried out for E d =16 MeV. The inelastic-scattering data have been analyzed using the DWBA with a collective and a microscopic model form-factor and also by using the coupled-channels formalism with a vibrational model form-factor. It is observed that while the cross-section angular-distribution data for the two 2 + states at E x =7.012 and 8.318 MeV are very similar, the corresponding vector analyzing powers are quite different. The results of the analyses indicate that the distinctive characteristics probably arise from the difference in the relative importance of the proton and neutron components in the transition amplitude. The 3 - state at E x =6.728 MeV is identified as predominantly a 1p-3h state. Although the deformation parameters are relatively large, the single-particle structure aspects play a more dominant role than channel-coupling effects in populating the inelastic states. The transfer reaction data have been analyzed using the DWBA for bound and unbound states. The importance of two-step processes has been investigated via coupled-reaction-channels calculations. The g.s. and the states with excitation energies 0.770, 3.103 and 4.78 MeV in 15 C are populated primarily by a one-step process with a small two-step contribution in the case of the 3.103 MeV state. The 4.22 MeV state is populated predominantly by two-step processes. The 4.78 and the 5.83 MeV states have been identified as 1p-2h and 3p-4h, [3]/[2] + state, respectively, in an earlier report. There is close similarity in the level structures and reaction mechanisms between the states of 15 C and 17 O populated via the (d, p) reaction. ((orig.))

Inter-comparison of High Energy Files (neutron-induced, from 20 to 150 MeV)

Energy Technology Data Exchange (ETDEWEB)

Lee, Young-Ouk; Fukahori, Tokio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1998-11-01

Recent new applications using accelerator-driven system require well-tested nuclear data when modeling the interaction of neutrons above 20 MeV. This work is aimed to review evaluation methods applied in currently available neutron high energy files above 20 to 150 MeV, to inter-compare their evaluated cross sections on some important isotopes, and to analyze resulting discrepancies. Through out these, integrities and consistencies of the high energy files are checked, applicability of physics models and evaluation methodologies are assessed, and some directions are derived to improve and expand current JENDL High Energy File. (author)

Energy dependence of relative abundances and periods of delayed neutron separate groups from neutron induced fission of 239Pu in the virgin neutron energy range 0.37-4.97 MeV

International Nuclear Information System (INIS)

Piksajkin, V.M.; Kazakov, L.E.; Isaev, S.T.; Korolev, G.G.; Roshchenko, V.A.; Tertychnyj, R.G.

2002-01-01

Relative yield and group period of delayed neutrons induced by the 239 Pu fission in the 0.37-4.97 MeV range were measured. Comparative analysis of experimental data was conducted in terms of middle period of half-life of delayed neutron nuclei-precursors. Character and scale of changing values of delayed neutron group parameters as changing excitation energy of fission compound-nucleus have been demonstrated for the first time. Considerable energy dependence of group parameters under the neutron induced 239 Pu fission that was expressed by the decreasing middle period of half-life of nuclei-precursors by 10 % in the 2.85 eV - 5 MeV range of virgin neutrons was detected [ru

Neutron activation analysis in Romania

International Nuclear Information System (INIS)

Apostolescu, St.

1985-01-01

The following basic nuclear facilities are used for neutron activation analysis: a 2000 KW VVR-S Nuclear Reactor, a U-200 Cyclotron, a 30 MeV Betatron, several 14 MeV neutron generators and a king size High Voltage tandem Van de'Graaff accelerator. The main domains of application of the thermal neutron activation analysis are: geology and mining, processing of materials, environment and biology, achaeology. Epithermal neutron activation analysis has been used for determination of uranium and thorium in ores with high Th/U ratios or high rare earth contents. One low energy accelerator, used as 14.1 Mev neutron source, is provided with special equipmen for oxigen and low mass elements determination. An useful alternating way to support fast neutron activation analysis is an accurate theoretical description of the fast neutron induced reactions based on the statistical model (Hauser-Feubach STAPRE code) and the preequilibrium decay geometry dependent model. A gravitational sample changer has been installed at the end of a beam line of the Cyclotron, which enables to perform charged particles activation analysis for protein determination in grains

The SCANDAL facility - How to measure elastic neutron scattering in the 50-130 MeV range

International Nuclear Information System (INIS)

Klug, Joakim

2001-01-01

The interest in neutrons of energies above 20 MeV is growing rapidly, since new applications are being developed or have been identified. Transmutation of nuclear waste and cancer therapy with neutron beams are two research fields that would benefit from new neutron scattering data at these energies. A facility for detection of scattered neutrons in the energy interval 50-130 MeV, SCANDAL (SCAttered Nucleon Detection AssembLy), has been developed and installed at the neutron beam facility of the The Svedberg Laboratory in Uppsala. It can be used to study the (n,n), (n,p) and (n,d) reactions. This thesis describes the layout of the setup, the experimental procedure, and data analysis principles. The performance of the spectrometer is illustrated with measurements of the (n,p) and (n,n) reactions on 1 H and 12 C. In addition, the neutron beam facility is described in some detail

Experimental Measurement of the Ratio of the Reaction Cross Section (n,2n) for the Natural Mixtures of Lead and Iron Isotopes with 14 MeV Neutrons by the Method of Moderated Neutron-Neutron Coincidences

International Nuclear Information System (INIS)

Panteleev, Ts.Ts.; Penchev, O.I.; Trifonov, A.I.; Troshev, T.M.; Christov, V.I.

1986-01-01

Neutron data are widely applied in nuclei physics and into practice as well. Data obtained by means of different measurement methods are of interest for increasing the accuracy and reliability of the recommended values for the cross sections of neutron interactions, with substance. The activation analysis method gives a possibility to obtain data about cross section interactions of 14 MeV neutrons with the nuclei σ (n,2n), σ( n,p), σ (n,pn), σ (n,α), etc. A serious shortcoming of this measuring method is the necessity of applying express methods of analysis of induced activities - restrictions connected with the life-times of the reaction products. It is also necessary to comply with the requirements for high accuracy in the data about the decay schemes and the absolute intensities of the γ-transitions in the investigated nuclei. The investigations directly measuring the output of the reaction, products from the targets, placed into the neutron beam, do not possess the shortcomings of the activation method but require serious demands toward the detecting apparatuses (ionization chambers, semiconducting and scintillation detectors, proportional counters, etc.). These demands are connected with the heavy background conditions of work at the beams for measurements of whatever partial cross sections. During the experimental measurements of the reactions by neutron emission for registration, it is necessary to slow them down to thermal energies, since only in this energy interval there exist sufficiently effective without threshold detectors. We have elaborated the experimental set-up allowing to measure the neutron multiplicity in an interaction. In the present work we have also used it for a relative measurement the the reaction cross section σ (n,2n) for Pe and Pb nuclei in their natural isotope mixtures. As it is known, this reaction has an important application for the blanket materials of thermonuclear reactors and for tritium fuel regeneration problem. The

Measurement of neutron-production double-differential cross sections for continuous neutron-incidence reaction up to 100 MeV

International Nuclear Information System (INIS)

Kunieda, Satoshi; Watanabe, Takehito; Shigyo, Nobuhiro; Ishibashi, Kenji; Satoh, Daiki; Nakamura, Takashi; Haight, Robert C.

2004-01-01

The inclusive measurements of neutron-incident neutron-production double-differential cross sections in intermediate energy range is now being carried out. Spallation neutrons are used as incident particles. As a part of this, the experiment was performed by using of NE213 liquid organic scintillators to detect outgoing-neutrons. Incident-neutron energy was determined by time-of-flight technique, and outgoing-neutron energy spectrum was derived by unfolding light-output spectrum of NE213 with response functions calculated by SCINFUL-R. Preliminary cross sections were obtained up to about 100 MeV, and were compared with calculations by the GNASH code. It is hoped to get pure measurements by using measured response functions for our detectors used in this study. (author)

Neutron emission in fission of highly excited californium nuclei (E* = 76 MeV)

International Nuclear Information System (INIS)

Blinov, M.V.; Bordyug, V.M.; Kozulin, E.M.; Levitovich, M.; Mozhaev, A.N.; Muzychka, Yu.A.; Penionzhkevich, Yu.E.; Pustyl'nik, B.I.

1990-01-01

Differential cross sections for neutron production have been measured in fission of excited californium nuclei produced in the reaction 238 U + 12 C (105 MeV). It follows from analysis of the experimental results that the number of neutrons emitted before fission considerably exceeds the number obtained in the framework of the standard statistical model. On the basis of the multiplicity of neutrons they authors have estimated the time of fission of the excited nucleus. The dependence of the number of neutrons and their average energies on the mass of the fragments is determined

Neutron quality parameters versus energy below 4 MeV from microdosimetric calculations

International Nuclear Information System (INIS)

Stinchcomb, T.G.; Borak, T.B.

1983-01-01

Charged-particle production by neutrons and the resulting energy-deposition spectra in micron-sized spheres of tissue of varying diameters were calculated from thermal energies to 4 MeV. These data were used to obtain dose-average values of several quality-indicating parameters as functions of neutron energy and of tissue sphere diameter. The contrast among the parameters is shown and discussed. Applications are made to two neutron spectra, one a fission spectrum in air and the other a moderated spectrum at the center of an irradiated cube of water

First measurement of the VESUVIO neutron spectrum in the 30-80 MeV energy range using a Proton Recoil Telescope technique

Science.gov (United States)

Cazzaniga, C.; Tardocchi, M.; Croci, G.; Frost, C.; Giacomelli, L.; Grosso, G.; Hjalmarsson, A.; Rebai, M.; Rhodes, N. J.; Schooneveld, E. M.; Gorini, G.

2013-11-01

Measurements of the fast neutron energy spectrum at the ISIS spallation source are reported. The measurements were performed with a Proton Recoil Telescope consisting of a thin plastic foil placed in the neutron beam and two scintillator detectors. Results in the neutron energy range 30 MeV < En < 80 MeV are in good agreement with Monte Carlo simulations of the neutron spectrum.

Properties of neutron sources

International Nuclear Information System (INIS)

1987-03-01

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

Features of the neutron spectra accompanying the fission of actinide nuclei