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Sample records for capture cross-section adjustments

  1. Integral-capture measurements and cross-section adjustments for Nd, Sm, and Eu

    International Nuclear Information System (INIS)

    Anderl, R.A.; Schmittroth, F.; Harker, Y.D.

    1981-07-01

    Integral-capture reaction rates are reported for 143 Nd, 144 Nd, 145 Nd, 147 Sm, 151 Eu, 152 Eu, 153 Eu, and 154 Eu irradiated in different neutron spectra in EBR-II. These reaction rates are based primarily on mass-spectrometric measurements of the isotopic atom ratios of the capture product to the target nuclide. The neutron spectra are characterized using passive neutron dosimetry and spectrum-unfolding with the FERRET least-squares data analysis code. Reaction rates for the neutron spectrum monitors were determined by the radiometric technique using Ge(Li) spectrometers. These rates are also reported here. The integral data for the rare-earth samples and for the spectrum monitors were used in multigroup flux/cross-section adtustment analyses with FERRET to generate adjustments to 47 group representations of the ENDF/B-IV capture cross sections for the rare-earth isotopes. These adjusted cross sections are in good agreement with recent differential data and with adjusted cross sections based on STEK integral data. Examples are given of the use of the adjusted cross sections and covariance matrices for cross-section evaluation

  2. Measurements of neutron capture cross sections

    International Nuclear Information System (INIS)

    Nakajima, Yutaka

    1984-01-01

    A review of measurement techniques for the neutron capture cross sections is presented. Sell transmission method, activation method, and prompt gamma-ray detection method are described using examples of capture cross section measurements. The capture cross section of 238 U measured by three different prompt gamma-ray detection methods (large liquid scintillator, Moxon-Rae detector, and pulse height weighting method) are compared and their discrepancies are resolved. A method how to derive the covariance is described. (author)

  3. Capture cross sections on unstable nuclei

    Science.gov (United States)

    Tonchev, A. P.; Escher, J. E.; Scielzo, N.; Bedrossian, P.; Ilieva, R. S.; Humby, P.; Cooper, N.; Goddard, P. M.; Werner, V.; Tornow, W.; Rusev, G.; Kelley, J. H.; Pietralla, N.; Scheck, M.; Savran, D.; Löher, B.; Yates, S. W.; Crider, B. P.; Peters, E. E.; Tsoneva, N.; Goriely, S.

    2017-09-01

    Accurate neutron-capture cross sections on unstable nuclei near the line of beta stability are crucial for understanding the s-process nucleosynthesis. However, neutron-capture cross sections for short-lived radionuclides are difficult to measure due to the fact that the measurements require both highly radioactive samples and intense neutron sources. Essential ingredients for describing the γ decays following neutron capture are the γ-ray strength function and level densities. We will compare different indirect approaches for obtaining the most relevant observables that can constrain Hauser-Feshbach statistical-model calculations of capture cross sections. Specifically, we will consider photon scattering using monoenergetic and 100% linearly polarized photon beams. Challenges that exist on the path to obtaining neutron-capture cross sections for reactions on isotopes near and far from stability will be discussed.

  4. Capture cross sections on unstable nuclei

    Directory of Open Access Journals (Sweden)

    Tonchev A.P.

    2017-01-01

    Full Text Available Accurate neutron-capture cross sections on unstable nuclei near the line of beta stability are crucial for understanding the s-process nucleosynthesis. However, neutron-capture cross sections for short-lived radionuclides are difficult to measure due to the fact that the measurements require both highly radioactive samples and intense neutron sources. Essential ingredients for describing the γ decays following neutron capture are the γ-ray strength function and level densities. We will compare different indirect approaches for obtaining the most relevant observables that can constrain Hauser-Feshbach statistical-model calculations of capture cross sections. Specifically, we will consider photon scattering using monoenergetic and 100% linearly polarized photon beams. Challenges that exist on the path to obtaining neutron-capture cross sections for reactions on isotopes near and far from stability will be discussed.

  5. Neutron capture cross section of ^243Am

    Science.gov (United States)

    Jandel, M.

    2009-10-01

    The Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory (LANL) was used for neutron capture cross section measurement on ^243Am. The high granularity of DANCE (160 BaF2 detectors in a 4π geometry) enables the efficient detection of prompt gamma-rays following neutron capture. DANCE is located on the 20.26 m neutron flight path 14 (FP14) at the Manuel Lujan Jr. Neutron Scattering Center at the Los Alamos Neutron Science Center (LANSCE). The methods and techniques established in [1] were used for the determination of the ^243Am neutron capture cross section. The cross sections were obtained in the range of neutron energies from 0.02 eV to 400 keV. The resonance region was analyzed using SAMMY7 and resonance parameters were extracted. The results will be compared to existing evaluations and calculations. Work was performed under the auspices of the U.S. Department of Energy at Los Alamos National Laboratory by the Los Alamos National Security, LLC under Contract No. DE-AC52-06NA25396 and at Lawrence Livermore National Laboratory by the Lawrence Livermore National Security, LLC under Contract No. DE-AC52-07NA27344. [4pt] [1] M. Jandel et al., Phys. Rev. C78, 034609 (2008)

  6. Neutron capture cross sections of Kr

    Directory of Open Access Journals (Sweden)

    Fiebiger Stefan

    2017-01-01

    Full Text Available Neutron capture and β− -decay are competing branches of the s-process nucleosynthesis path at 85Kr [1], which makes it an important branching point. The knowledge of its neutron capture cross section is therefore essential to constrain stellar models of nucleosynthesis. Despite its importance for different fields, no direct measurement of the cross section of 85Kr in the keV-regime has been performed. The currently reported uncertainties are still in the order of 50% [2, 3]. Neutron capture cross section measurements on a 4% enriched 85Kr gas enclosed in a stainless steel cylinder were performed at Los Alamos National Laboratory (LANL using the Detector for Advanced Neutron Capture Experiments (DANCE. 85Kr is radioactive isotope with a half life of 10.8 years. As this was a low-enrichment sample, the main contaminants, the stable krypton isotopes 83Kr and 86Kr, were also investigated. The material was highly enriched and contained in pressurized stainless steel spheres.

  7. Electron Capture Cross Sections for Stellar Nucleosynthesis

    Directory of Open Access Journals (Sweden)

    P. G. Giannaka

    2015-01-01

    Full Text Available In the first stage of this work, we perform detailed calculations for the cross sections of the electron capture on nuclei under laboratory conditions. Towards this aim we exploit the advantages of a refined version of the proton-neutron quasiparticle random-phase approximation (pn-QRPA and carry out state-by-state evaluations of the rates of exclusive processes that lead to any of the accessible transitions within the chosen model space. In the second stage of our present study, we translate the abovementioned e--capture cross sections to the stellar environment ones by inserting the temperature dependence through a Maxwell-Boltzmann distribution describing the stellar electron gas. As a concrete nuclear target we use the 66Zn isotope, which belongs to the iron group nuclei and plays prominent role in stellar nucleosynthesis at core collapse supernovae environment.

  8. Capture cross sections for very heavy systems

    International Nuclear Information System (INIS)

    Rowley, N.; Grar, N.; Ntshangase, S.S.

    2006-01-01

    In intermediate-mass systems, collective excitations of the target and projectile can greatly enhance the sub-barrier capture cross section σ cap by giving rise to a distribution of Coulomb barriers. For such systems, capture essentially leads directly to fusion (formation of a compound nucleus (CN)), which then decays through the emission of light particles (neutrons, protons, and alpha particles). Thus the evaporation-residue (ER) cross section is essentially equal to σ cap . For heavier systems the experimental situation is significantly more complicated due to the presence of quasifission (QF) (rapid separation into two fragments before the CN is formed) and by fusion-fission (FF) of the CN itself. Thus three cross sections need to be measured in order to evaluate σ cap . Although the ER essentially recoil along the beam direction. QF and FF fragments are scattered to all angles and require the measurement of angular distribution in order to obtain the excitation function and barrier distribution for capture. Two other approaches to this problem exist. If QF is not important, one can still measure just the ER cross section and try to reconstruct the corresponding σ cap through use of an evaporation-model code that takes account of the FF degree of freedom. Some earlier results on σ cap obtained in this way will be re-analyzed with detail coupled-channels calculations, and the extra-push phenomenon discussed. One may also try to obtain σ cap by exploiting unitarity, that is, by measuring instead the flux of particles corresponding to quasielastic (QE) scattering from the Coulomb barrier. Some new QE results obtained for the 86 Kr + 208 Pb system at iThemba LABS in South Africa will be presented [ru

  9. Neutron capture cross section of $^{93}$Zr

    CERN Document Server

    We propose to measure the neutron capture cross section of the radioactive isotope $^{93}$Zr. This project aims at the substantial improvement of existing results for applications in nuclear astrophysics and emerging nuclear technologies. In particular, the superior quality of the data that can be obtained at n_TOF will allow on one side a better characterization of s-process nucleosynthesis and on the other side a more accurate material balance in systems for transmutation of nuclear waste, given that this radioactive isotope is widely present in fission products.

  10. Measurement of thermal neutron capture cross section

    International Nuclear Information System (INIS)

    Huang Xiaolong; Han Xiaogang; Yu Weixiang; Lu Hanlin; Zhao Wenrong

    2001-01-01

    The thermal neutron capture cross sections of 71 Ga(n, γ) 72 Ga, 94 Zr(n, γ) 95 Zr and 191 Ir(n, γ) 192 Ir m1+g,m2 reactions were measured by using activation method and compared with other measured data. Meanwhile the half-life of 72 Ga was also measured. The samples were irradiated with the neutron in the thermal column of heavy water reactor of China Institute of Atomic Energy. The activities of the reaction products were measured by well-calibrated Ge(Li) detector

  11. Resonance capture cross section of 207Pb

    CERN Document Server

    Domingo-Pardo, C.; Aerts, G.; Alvarez-Pol, H.; Alvarez-Velarde, F.; Andriamonje, S.; Andrzejewski, J.; Assimakopoulos, P.; Audouin, L.; Badurek, G.; Baumann, P.; Becvar, F.; Berthoumieux, E.; Bisterzo, S.; Calvino, F.; Cano-Ott, D.; Capote, R.; Carrapico, C.; Cennini, P.; Chepel, V.; Chiaveri, E.; Colonna, N.; Cortes, G.; Couture, A.; Cox, J.; Dahlfors, M.; David, S.; Dillman, I.; Dolfini, R.; Dridi, W.; Duran, I.; Eleftheriadis, C.; Embid-Segura, M.; Ferrant, L.; Ferrari, A.; Ferreira-Marques, R.; Fitzpatrick, L.; Frais-Koelbl, H.; Fujii, K.; Furman, W.; Gallino, R.; Goncalves, I.; Gonzalez-Romero, E.; Goverdovski, A.; Gramegna, F.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Haas, B.; Haight, R.; Heil, M.; Herrera-Martinez, A.; Igashira, M.; Isaev, S.; Jericha, E.; Kadi, Y.; Kappeler, F.; Karamanis, D.; Karadimos, D.; Kerveno, M.; Ketlerov, V.; Koehler, P.; Konovalov, V.; Kossionides, E.; Krticka, M.; Lamboudis, C.; Leeb, H.; Lindote, A.; Lopes, I.; Lozano, M.; Lukic, S.; Marganiec, J.; Marrone, S.; Mastinu, P.; Mengoni, A.; Milazzo, P.M.; Moreau, C.; Mosconi, M.; Neves, F.; Oberhummer, H.; Oshima, M.; O'Brien, S.; Pancin, J.; Papachristodoulou, C.; Papadopoulos, C.; Paradela, C.; Patronis, N.; Pavlik, A.; Pavlopoulos, P.; Perrot, L.; Plag, R.; Plompen, A.; Plukis, A.; Poch, A.; Pretel, C.; Quesada, J.; Rauscher, T.; Reifarth, R.; Rosetti, M.; Rubbia, C.; Rudolf, G.; Rullhusen, P.; Salgado, J.; Sarchiapone, L.; Savvidis, I.; Stephan, C.; Tagliente, G.; Tain, J.L.; Tassan-Got, L.; Tavora, L.; Terlizzi, R.; Vannini, G.; Vaz, P.; Ventura, A.; Villamarin, D.; Vincente, M.C.; Vlachoudis, V.; Vlastou, R.; Voss, F.; Walter, S.; Wendler, H.; Wiescher, M.; Wisshak, K.

    2006-01-01

    The radiative neutron capture cross section of 207Pb has been measured at the CERN neutron time of flight installation n_TOF using the pulse height weighting technique in the resolved energy region. The measurement has been performed with an optimized setup of two C6D6 scintillation detectors, which allowed us to reduce scattered neutron backgrounds down to a negligible level. Resonance parameters and radiative kernels have been determined for 16 resonances by means of an R-matrix analysis in the neutron energy range from 3 keV to 320 keV. Good agreement with previous measurements was found at low neutron energies, whereas substantial discrepancies appear beyond 45 keV. With the present results, we obtain an s-process contribution of 77(8)% to the solar abundance of 207Pb. This corresponds to an r-process component of 23(8)%, which is important for deriving the U/Th ages of metal poor halo stars.

  12. Precise measurements of neutron capture cross sections for FP

    International Nuclear Information System (INIS)

    Nakamura, Shoji; Harada, Hideo; Katoh, Toshio

    2000-01-01

    The thermal neutron capture cross sections (σ 0 ) and the resonance integrals (I 0 ) of some fission products (FP), such as 137 Cs, 90 Sr, 99 Tc, 129 I and 135 Cs, were measured by the activation and γ-ray spectroscopic methods. Moreover, the cross section measurements were done for other FP elements, such as 127 I, 133 Cs and 134 Cs. This paper provides the summary of the FP cross section measurements, which have been performed by authors. (author)

  13. Thermal neutron capture cross sections of tellurium isotopes

    International Nuclear Information System (INIS)

    Tomandl, I.; Honzatko, J.; Egidy, T. von; Wirth, H.-F.; Belgya, T.; Lakatos, M.; Szentmiklosi, L.; Revay, Zs.; Molnar, G.L.; Firestone, R.B.; Bondarenko, V.

    2003-01-01

    New values for thermal neutron capture cross sections of the tellurium isotopes 122 Te, 124 Te, 125 Te, 126 Te, 128 Te, and 130 Te are reported. These values are based on a combination of newly determined partial γ-ray cross sections obtained from experiments on targets contained natural Te and γ intensities per capture of individual Te isotopes. Isomeric ratios for the thermal neutron capture on the even tellurium isotopes are also given

  14. Thermal neutron capture cross sections of tellurium isotopes

    International Nuclear Information System (INIS)

    Tomandl, I.; Honzatko, J.; Egidy, T. von; Wirth, H.-F.; Belgya, T.; Lakatos, M.; Szentmiklosi, L.; Revay, Zs.; Molnar, G.L.; Firestone, R.B.; Bondarenko, V.

    2004-01-01

    New values for thermal neutron capture cross sections of the tellurium isotopes 122Te, 124Te, 125Te, 126Te, 128Te, and 130Te are reported. These values are based on a combination of newly determined partial g-ray cross sections obtained from experiments on targets contained natural Te and gamma intensities per capture of individual Te isotopes. Isomeric ratios for the thermal neutron capture on the even tellurium isotopes are also given

  15. Thermal neutron capture cross sections of tellurium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Tomandl, I.; Honzatko, J.; von Egidy, T.; Wirth, H.-F.; Belgya, T.; Lakatos, M.; Szentmiklosi, L.; Revay, Zs.; Molnar, G.L.; Firestone, R.B.; Bondarenko, V.

    2004-03-01

    New values for thermal neutron capture cross sections of the tellurium isotopes 122Te, 124Te, 125Te, 126Te, 128Te, and 130Te are reported. These values are based on a combination of newly determined partial g-ray cross sections obtained from experiments on targets contained natural Te and gamma intensities per capture of individual Te isotopes. Isomeric ratios for the thermal neutron capture on the even tellurium isotopes are also given.

  16. Adjustement of multigroup cross sections using fast reactor integral data

    International Nuclear Information System (INIS)

    Renke, C.A.C.

    1982-01-01

    A methodology for the adjustment of multigroup cross section is presented, structured with aiming to compatibility the limitated number of measured values of integral parameters known and disponible, and the great number of cross sections to be adjusted the group of cross section used is that obtained from the Carnaval II calculation system, understanding as formular the sets of calculation methods and data bases. The adjustment is realized, using the INCOAJ computer code, developed in function of one statistical formulation, structural from the bayer considerations, taking in account the measurement processes of cross section and integral parameters defined on statistical bases. (E.G.) [pt

  17. Neutron-capture cross sections from indirect measurements

    Directory of Open Access Journals (Sweden)

    Scielzo N.D.

    2012-02-01

    Full Text Available Cross sections for compound-nuclear reactions reactions play an important role in models of astrophysical environments and simulations of the nuclear fuel cycle. Providing reliable cross section data remains a formidable task, and direct measurements have to be complemented by theoretical predictions and indirect methods. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f reactions, but need to be improved upon for applications to capture reactions.

  18. Neutron-capture Cross Sections from Indirect Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Escher, J E; Burke, J T; Dietrich, F S; Ressler, J J; Scielzo, N D; Thompson, I J

    2011-10-18

    Cross sections for compound-nuclear reactions play an important role in models of astrophysical environments and simulations of the nuclear fuel cycle. Providing reliable cross section data remains a formidable task, and direct measurements have to be complemented by theoretical predictions and indirect methods. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f) reactions, but need to be improved upon for applications to capture reactions.

  19. Some problem areas in capture cross-section measurements

    International Nuclear Information System (INIS)

    Moxon, M.C.; Gayther, D.B.; Sowerby, M.G.

    1975-01-01

    This paper outlines some of the problems that have been encountered and are envisaged in the measurement and evaluation of capture cross-sections. Particular emphasis is placed on the cross-sections of the structural materials (Fe, Ni, Cr) used in fast reactors. The topics considered are the influence of scattered neutrons in capture detectors, the determination of background, sample thickness corrections, and the theoretical representation of resonance parameters. (author)

  20. Second order effects in adjustment processes of cross sections

    International Nuclear Information System (INIS)

    Silva, F.C. da; D'Angelo, A.; Gandini, A.; Rado, V.

    1982-01-01

    An iterative processe, that take in account the non linear effects of some integral quantities in relation to cross sections, is used to execute an adjustment of cross sections of some elements that constitute the fast reactors shielding. (E.G.) [pt

  1. Comparison of fission and capture cross sections of minor actinides

    International Nuclear Information System (INIS)

    Nakagawa, Tsuneo; Iwamoto, Osamu

    2003-01-01

    The fission and capture cross sections of minor actinides given in JENDL-3.3 are compared with other evaluated data and experimental data. The comparison was made for 32 nuclides of Th-227, 228, 229, 230, 233, 234, Pa-231, 232, 233, U-232, 234, 236, 237, Np-236, 237, 238, Pu-236, 237, 238, 242, 244, Am-241, 242, 242m, 243, Cm-242, 243, 244, 245, 246, 247 and 248. Given in the present report are figures of these cross sections and tables of cross sections at 0.0253 eV and resonance integrals. (author)

  2. Neutron capture cross section standards for BNL 325, Fourth Edition

    International Nuclear Information System (INIS)

    Holden, N.E.

    1981-01-01

    This report evaluates the experimental data and recommends values for the thermal neutron cross sections and resonance integrals for the neutron capture reactions: 55 Mn(n,γ), 59 Co(n,γ) and 197 Au(n,γ). The failure of lithium and boron as standards due to the natural variation of the absorption cross sections of these elements is discussed. The Westcott convention, which describes the neutron spectrum as a thermal Maxwellian distribution with an epithermal component, is also discussed

  3. Capture cross section and resonance parameters of thulium-169

    International Nuclear Information System (INIS)

    Arbo, J.C.; Felvinci, J.P.; Melkonian, E.; Havens, W.W. Jr.

    1975-01-01

    The previously analyzed energy range for thulium capture resonance parameters is extended from 1 keV to 2 keV. In addition, point and group averaged thulium cross section curves are extended to above 2 keV and 181 Ta impurity levels are discussed. (SDF)

  4. Measurements of neutron capture cross sections of wolfram and thulium

    International Nuclear Information System (INIS)

    Xia Yijun; Wang Chunhao; Yang Jingfu; Yang Zhihua; Luo Xiaobing

    1992-01-01

    The neutron capture cross sections of wolfram and thulium were measured in the energy range from 10 to 100 KeV using gold as the standard. Kinematically collimated neutrons were produced via the 7 Li(p, n) 7 Be reaction with a 2.5 MV pulsed Van de Graaff accelerator at Sichuan University. The capture events were detected by a pair of Moxon-Rae detectors. Time-of-flight technique was used to improve the signal-background ratio. The present results are compared with data by other authors. The capture cross section were calculated from 10 to 100 KeV for two nuclides by the Hauser-Feshbach statistical theory with width fluctuation correction. The nonstatistical effects such as potential capture and radiative capture in elastic and inelastic channels of a compound nucleus were included in the calculations. The calculated results show that the nonstatistical contribution to the capture cross sections is negligible compared with that of the statistical effects

  5. Neutron capture cross section measurements: case of lutetium isotopes

    International Nuclear Information System (INIS)

    Roig, O.; Meot, V.; Belier, G.

    2011-01-01

    The neutron radiative capture is a nuclear reaction that occurs in the presence of neutrons on all isotopes and on a wide energy range. The neutron capture range on Lutetium isotopes, presented here, illustrates the variety of measurements leading to the determination of cross sections. These measurements provide valuable fundamental data needed for the stockpile stewardship program, as well as for nuclear astrophysics and nuclear structure. Measurements, made in France or in United-States, involving complex detectors associated with very rare targets have significantly improved the international databases and validated models of nuclear reactions. We present results concerning the measurement of neutron radiative capture on Lu 173 , Lu 175 , Lu 176 and Lu 177m , the measurement of the probability of gamma emission in the substitution reaction Yb 174 (He 3 ,pγ)Lu 176 . The measurement of neutron cross sections on Lu 177m have permitted to highlight the process of super-elastic scattering

  6. PIA and REWIND: Two New Methodologies for Cross Section Adjustment

    Energy Technology Data Exchange (ETDEWEB)

    Palmiotti, G.; Salvatores, M.

    2017-02-01

    This paper presents two new cross section adjustment methodologies intended for coping with the problem of compensations. The first one PIA, Progressive Incremental Adjustment, gives priority to the utilization of experiments of elemental type (those sensitive to a specific cross section), following a definite hierarchy on which type of experiment to use. Once the adjustment is performed, both the new adjusted data and the new covariance matrix are kept. The second methodology is called REWIND (Ranking Experiments by Weighting for Improved Nuclear Data). This new proposed approach tries to establish a methodology for ranking experiments by looking at the potential gain they can produce in an adjustment. Practical applications for different adjustments illustrate the results of the two methodologies against the current one and show the potential improvement for reducing uncertainties in target reactors.

  7. Fast neutron capture cross section facility at Cadarache

    International Nuclear Information System (INIS)

    Le Rigoleur, C.; Arnaud, A.

    1975-01-01

    The total energy weighting technique has been applied to measure absolute fast neutron capture cross section at Cadarache. We use a non hydrogeneous liquid scintillator to detect the gamma from the cascade. The neutron flux is measured with a B 10 INa(Tl) detector or Li 6 glass scintillator of well known efficiency. Time of flight technique is used with on line digital computer data processing. (orig.) [de

  8. Stellar neutron capture cross sections of the Ba isotopes

    International Nuclear Information System (INIS)

    Voss, F.; Wisshak, K.; Guber, K.; Kaeppeler, F.; Reffo, G.

    1994-03-01

    The neutron capture cross sections of 134 Ba, 135 Ba, 136 Ba, and 137 Ba were measured in the energy range from 5 to 225 keV at the Karlsruhe 3.75 MV Van de Graaff accelerator. Neutrons were produced via the 7 Li(p,n) 7 Be reaction by bombarding metallic Li targets with a pulsed proton beam. Capture events were registered with the Karlsruhe 4π Barium Fluoride Detector. Several runs have been performed under different experimental conditions to study the systematic uncertainties, which resulted mainly from the large ratios of total to capture cross sections of up to 400. The cross section ratios were determined with an overall uncertainty of ∼3%, an improvement by factors of five to eight compared to existing data. Severe discrepancies were found with respect to previous results. Maxwellian averaged neutron capture cross sections were calculated for thermal energies between kT=10 keV and 100 keV. These stellar cross sections were used in an s-process analysis. For the s-only isotopes 134 Ba and 136 Ba the N s ratio was determined to 0.875±0.025. Hence, a significant branching of the s-process path at 134 Cs can be claimed for the first time, in contrast to predictions from the classical approach. This branching yields information on the s-process temperature, indicating values around T 8 =2. The new cross sections are also important for the interpretation of barium isotopic anomalies, which were recently discovered in SiC grains of carbonaceous chondrite meteorites. Together with the results from previous experiments on tellurium and samarium, a general improvement of the N s systematics in the mass range A=120 to 150 is achieved. This allows for a more reliable separation of s- and r-process yields, resulting in an improved assignment of the respective contributions to elemental barium that is required for comparison with stellar observations. (orig.) [de

  9. Neutron capture cross section standards for BNL-325

    International Nuclear Information System (INIS)

    Holden, N.E.

    1980-01-01

    The most common cross section standards for capture reactions in the thermal neutron energy region are gold, cobalt, and manganese. In preparation for the fourth edition of BNL-325, data on the thermal cross section and resonance integral were evaluated for these three standards. For gold, only measurements below the Bragg scattering cutoff were used and extrapolated to a neutron velocity of 2200 meters/second. A non 1/v correction due to the 4.9 eV resonance was made. The resonance integral is based on Jirlow's integral measurement and Tellier's parameters. The resonance integrals for cobalt and manganese are based solely on integral measurements because the capture widths of the first major resonance either vary by 20% in various measurements (cobalt), or have never been measured (manganese). Recommended thermal cross sections and resonance integrals are respectively gold: 98.65/plus or minus/0.9 barns, 1550/plus or minus/28 barns; cobalt: 37.18/plus or minus/0.06 barns, 74.2/plus or minus/2.0 barns and manganese: 13.3/plus or minus/0.2 barns, and 14.0/plus or minus/0.3 barns. 72 refs

  10. Evaluations of fission product capture cross sections for ENDF/B-V

    International Nuclear Information System (INIS)

    Schenter, R.E.; Johnson, D.L.; Mann, F.M.; Schmittroth, F.

    1979-01-01

    Capture cross section evaluations were made for the 36 most important fission product absorbers in a fast reactor system. These evaluations were obtained by use of a generalized least-squares approach with calculations being performed with the computer code FERRET. These results will provide the major revisions to the ENDF/B-IV Fission Product Cross Section File which will be released as part of ENDF/B-V. Input for the cross section adjustment calculations included both integral and differential experimental data results. The differential cross sections and their uncertainties were obtained from the CSIRS library. Integral measurement results came from CFRMF and STEK Assemblies 500, 1000, 2000, 3000, and 4000. Comparisons of these evaluations with recent capture measurements are presented. 14 figures

  11. Electron capture cross sections by O+ from atomic He

    International Nuclear Information System (INIS)

    Joseph, Dwayne C; Saha, Bidhan C

    2009-01-01

    The adiabatic representation is used in both the quantal and semi classical molecular orbital close coupling methods (MOCC) to evaluate charge exchange cross sections. Our results show good agreement with experimental cross sections

  12. Electron capture cross sections by O+ from atomic He

    Science.gov (United States)

    Joseph, Dwayne C.; Saha, Bidhan C.

    2009-11-01

    The adiabatic representation is used in both the quantal and semi classical molecular orbital close coupling methods (MOCC) to evaluate charge exchange cross sections. Our results show good agreement with experimental cross sections

  13. Utilization of cross-section covariance data in FBR core nuclear design and cross-section adjustment

    International Nuclear Information System (INIS)

    Ishikawa, Makoto

    1994-01-01

    In the core design of large fast breeder reactors (FBRs), it is essentially important to improve the prediction accuracy of nuclear characteristics from the viewpoint of both reducing cost and insuring reliability of the plant. The cross-section errors, that is, covariance data are one of the most dominant sources for the prediction uncertainty of the core parameters, therefore, quantitative evaluation of covariance data is indispensable for FBR core design. The first objective of the present paper is to introduce how the cross-section covariance data are utilized in the FBR core nuclear design works. The second is to delineate the cross-section adjustment study and its application to an FBR design, because this improved design method markedly enhances the needs and importance of the cross-section covariance data. (author)

  14. Isotonic and isotopic dependence of the radiative neutron capture cross-section on the neutron excess

    International Nuclear Information System (INIS)

    Trofimov, Yu.N.

    1991-01-01

    The radiative neutron capture cross-section of nuclei has been derived as a function of neutron excess on the basis of the exponential dependence of the cross-section on the reaction energy. It is shown that unknown cross-sections of stable and radioactive nuclei may be evaluated by using the isotonic and isotopic dependence together with available reference cross-section measurements. (author). 4 refs, 3 figs

  15. Resonance parameters for measured keV neutron capture cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Musgrove, A.R. de L

    1969-05-01

    All available neutron capture cross sections in the keV region ({approx} to 100 keV) have been fitted with resonance parameters. Capture cross sections for nuclides with reasonably well known average s-wave parameters, but no measured cross section, have been calculated and tabulated using p-and d- wave strength functions interpolated between fitted values. Several of these nuclides are of interest in the theory of slow nucleosynthesis of heavy elements in stars, and the product of cosmic abundance (due to the s-process) and capture cross section at 30 keV has been plotted versus mass number. (author)

  16. Thermal capture cross section for 58Ni (n,γ)59 Ni reaction

    International Nuclear Information System (INIS)

    Carbonari, A.W.; Pecequilo, B.R.S.

    1989-01-01

    The 58 Ni total thermal capture cross section was determined by suming the partial cross sections calculated for the primary transitions of the reaction 58 Ni (n,γ) 59 Ni. The primary transitions energies and intensities were determined from the 58 Ni thermal neutrons prompt gamma capture gamma rays spectrum in the 3.7 to 9.3 MeV region. The obtained value for the total cross section was 4.52 + 0.10b. (author) [pt

  17. Simple, empirical approach to predict neutron capture cross sections from nuclear masses

    Science.gov (United States)

    Couture, A.; Casten, R. F.; Cakirli, R. B.

    2017-12-01

    Background: Neutron capture cross sections are essential to understanding the astrophysical s and r processes, the modeling of nuclear reactor design and performance, and for a wide variety of nuclear forensics applications. Often, cross sections are needed for nuclei where experimental measurements are difficult. Enormous effort, over many decades, has gone into attempting to develop sophisticated statistical reaction models to predict these cross sections. Such work has met with some success but is often unable to reproduce measured cross sections to better than 40 % , and has limited predictive power, with predictions from different models rapidly differing by an order of magnitude a few nucleons from the last measurement. Purpose: To develop a new approach to predicting neutron capture cross sections over broad ranges of nuclei that accounts for their values where known and which has reliable predictive power with small uncertainties for many nuclei where they are unknown. Methods: Experimental neutron capture cross sections were compared to empirical mass observables in regions of similar structure. Results: We present an extremely simple method, based solely on empirical mass observables, that correlates neutron capture cross sections in the critical energy range from a few keV to a couple hundred keV. We show that regional cross sections are compactly correlated in medium and heavy mass nuclei with the two-neutron separation energy. These correlations are easily amenable to predict unknown cross sections, often converting the usual extrapolations to more reliable interpolations. It almost always reproduces existing data to within 25 % and estimated uncertainties are below about 40 % up to 10 nucleons beyond known data. Conclusions: Neutron capture cross sections display a surprisingly strong connection to the two-neutron separation energy, a nuclear structure property. The simple, empirical correlations uncovered provide model-independent predictions of

  18. Capture cross sections for Cr, Fe and Ni

    International Nuclear Information System (INIS)

    Corvi, F.

    1990-01-01

    Since stainless steel represents about 25% of the volume of a fast power reactor, its constituent elements strongly influence its two main neutronic parameters: critical enrichment and breeding gain. Also, capture in the narrow p and d-wave resonances of Cr, Fe and Ni contributes as much as 10 to 15% of the Doppler coefficient of reactivity. Following sensitivity calculations, typical accuracy requirements in the energy range 0.1-100 keV are 5-10% for capture in Fe and 10-20% for capture in Ni and Cr. 11 refs, 2 tabs

  19. Optical and statistical model calculation of the americium 242m capture cross section

    International Nuclear Information System (INIS)

    Tellier, Henry.

    1981-04-01

    The capture cross sections of Am 242m can be deduced from resonances analysis at low energy and computed with theoretical models at high energy. In this work, a coherent set of cross sections which reproduced the experimental values of the fission cross sections is computed. These calculations were performed for an energy of the incoming neutron between 1 keV and 1 MeV

  20. Five-dimensional black hole capture cross sections

    International Nuclear Information System (INIS)

    Gooding, Cisco; Frolov, Andrei V.

    2008-01-01

    We study scattering and capture of particles by a rotating black hole in the five-dimensional spacetime described by the Myers-Perry metric. The equations of geodesic motion are integrable, and allow us to calculate capture conditions for a free particle sent towards a black hole from infinity. We introduce a three-dimensional impact parameter describing asymptotic initial conditions in the scattering problem for a given initial velocity. The capture surface in impact parameter space is a sphere for a nonrotating black hole, and is deformed for a rotating black hole. We obtain asymptotic expressions that describe such deformations for small rotational parameters, and use numerical calculations to investigate the arbitrary rotation case, which allows us to visualize the capture surface as extremal rotation is approached

  1. Thermal neutron capture cross section for the K isomer 177Lum

    International Nuclear Information System (INIS)

    Belier, G.; Roig, O.; Daugas, J.-M.; Giarmana, O.; Meot, V.; Letourneau, A.; Marie, F.; Foucher, Y.; Aupiais, J.; Abt, D.; Jutier, Ch.; Le Petit, G.; Bettoni, C.; Gaudry, A.; Veyssiere, Ch.; Barat, E.; Dautremer, T.; Trama, J.-Ch.

    2006-01-01

    The thermal neutron radiative capture cross section for the K isomeric state in 177 Lu has been measured for the first time. Several 177 Lu m targets have been prepared and irradiated in various neutron fluxes at the Lauee Langevin Institute in Grenoble and at the CEA reactors OSIRIS and ORPHEE in Saclay. The method consists of measuring the 178 Lu activity by γ-ray spectroscopy. The values obtained in four different neutron spectra have been used to calculate the resonance integral of the radiative capture cross section for 177 Lu m . In addition, an indirect method leads to the determination of the 177 Lu g neutron radiative capture cross section

  2. Use of gamma ray strength functions for predicting the neutron capture cross section of 88Y

    International Nuclear Information System (INIS)

    Gardner, D.G.; Gardner, M.A.

    1977-01-01

    The present study indicates that the estimation of the gamma-ray strength function is the approach least subject to error when unmeasured capture cross sections are to be computed. An estimate is given for the 88 γ(n,γ) cross section

  3. Measurements and calculations of integral capture cross-sections of structural materials in fast reactor spectra

    International Nuclear Information System (INIS)

    Seth, S.; Brunson, G.; Gmuer, K.; Jermann, M.; McCombie, C.; Richmond, R.; Schmocker, U.

    1979-01-01

    This paper relates the checking of integral data of steel and iron in fast reactor lattices. The fully-rodded GCFR benchmark lattice of the zero-energy reactor PROTEUS was successively modified by replacing the PuO 2 -UO 2 fuel rods by steel-18/8 or steel-37 (iron) rods. The neutron spectra of the modified lattices in fact have median energies close to that of a typical LMFBR. The replacement of fuel by the structural material of interest was such that in each case the value of k(infinity) was reduced to near-unity. This allowed the measurement of the lattice-k(infinity) by the null-reactivity technique. In addition, the principal reaction rates (namely U238 capture and fission, relative to Pu239 fission) and the neutron spectrum were measured. These directly measured integral data which are particularly sensitive to the steel cross-sections can be used for the checking and systematic adjustment of data sets. The results may also be analysed so as to derive specific values for the integral capture cross-sections of steel and iron. Neutron balance equations were set-up for each of the lattices using the measured k(infinity) and reaction rates

  4. Electron capture cross-section of Au-Fe complex in silicon

    International Nuclear Information System (INIS)

    Ali, Akbar; Shafi, M; Majid, Abdul

    2006-01-01

    A deep level transient spectroscopy technique is applied to study the capture cross-section of an iron-gold complex. The thermal ionization energy obtained from emission rate data is found to be E c -0.36 eV. The Au-Fe complex is a single defect having a capture cross-section of 2.48x10 -16 cm 2 for electrons which is independent of temperature

  5. Electron capture cross-section of Au-Fe complex in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Akbar; Shafi, M; Majid, Abdul [Advance Materials Physics Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad (Pakistan)

    2006-10-15

    A deep level transient spectroscopy technique is applied to study the capture cross-section of an iron-gold complex. The thermal ionization energy obtained from emission rate data is found to be E{sub c} -0.36 eV. The Au-Fe complex is a single defect having a capture cross-section of 2.48x10{sup -16} cm{sup 2} for electrons which is independent of temperature.

  6. Derivation of capture and reaction cross sections from experimental quasi-elastic and elastic backscattering probabilities

    International Nuclear Information System (INIS)

    Sargsyan, V.V.; Adamian, G.G.; Antonenko, N.V.; Gomes, P.R.S.

    2014-01-01

    We suggest simple and useful methods to extract reaction and capture (fusion) cross sections from the experimental elastic and quasi-elastic backscattering data.The direct measurement of the reaction or capture (fusion) cross section is a difficult task since it would require the measurement of individual cross sections of many reaction channels, and most of them could be reached only by specific experiments. This would require different experimental setups not always available at the same laboratory and, consequently, such direct measurements would demand a large amount of beam time and would take probably some years to be reached. Because of that, the measurements of elastic scattering angular distributions that cover full angular ranges and optical model analysis have been used for the determination of reaction cross sections. This traditional method consists in deriving the parameters of the complex optical potentials which fit the experimental elastic scattering angular distributions and then of deriving the reaction cross sections predicted by these potentials. Even so, both the experimental part and the analysis of this latter method are not so simple. In the present work we present a much simpler method to determine reaction and capture (fusion) cross sections. It consists of measuring only elastic or quasi-elastic scattering at one backward angle, and from that, the extraction of the reaction or capture cross sections can easily be performed. (author)

  7. Measurement of keV-neutron capture cross sections and capture gamma-ray spectra of Er isotopes

    International Nuclear Information System (INIS)

    Harun-Ar-Rashid, A.K.M.; Igashira, Masayuki; Ohsaki, Toshiro

    2000-01-01

    Neutron capture cross sections and capture γ-ray spectra of 166,167, 168 Er were measured in the energy region of 10 to 550 keV. The measurements were performed with a pulsed 7 Li(p,n) 7 Be neutron source and a large anti-Compton NaI(Tl) γ-ray spectrometer. A pulse-height weighting technique and the standard capture cross sections of gold were used to derive the capture cross sections. The errors of the derived cross sections were about 5%. The present results were compared with other measurements and evaluations. The observed capture γ-ray pulse-height spectra were unfolded to obtain the corresponding γ-ray spectra. An anomalous shoulder was observed around 3 MeV in each of the capture γ-ray spectra. (author)

  8. Implementation of the rapid cross section adjustment approach at General Electric

    International Nuclear Information System (INIS)

    Cowan, C.L.; Kujawski, E.; Protsik, R.

    1978-01-01

    The General Electric rapid cross section adjustment approach was developed to use the shielding factor method for formulating multigroup cross sections. In this approach, space- and composition-dependent cross sections for a particular reactor or shield design are prepared from a generalized cross section library by the use of resonance self-shielding factors, and by the adjustment of elastic scattering cross sections for the local neutron flux spectra. The principal tool in the cross section adjustment package is the data processing code TDOWN. This code was specified to give the user a high degree of flexibility in the analysis of advanced reactor designs. Of particular interest in the analysis of critical experiments is the ability to carry out cell heterogeneity self-shielding calculations using a multiregion equivalence relationship, and the homogenization of the cross sections over the specified cell with the flux weighting obtained from transport theory calculations. Extensive testing of the rapid cross section adjustment approach, including comparisons with Monte Carlo methods, indicated that this approach can be utilized with a high degree of confidence in the design analysis of complex fast reactor systems. 2 figures, 1 table

  9. Neutron-induced capture cross sections via the surrogate reaction method

    International Nuclear Information System (INIS)

    Boutoux, G.; Jurado, B.; Aiche, M.; Barreau, G.; Capellan, N.; Companis, I.; Czajkowski, S.; Dassie, D.; Haas, B.; Mathieu, L.; Meot, V.; Bail, A.; Bauge, E.; Daugas, J. M.; Faul, T.; Gaudefroy, L.; Morel, P.; Pillet, N.; Roig, O.; Romain, P.; Taieb, J.; Theroine, C.; Burke, J.T.; Companis, I.; Derkx, X.; Gunsing, F.; Matea, I.; Tassan-Got, L.; Porquet, M.G.; Serot, O.

    2011-01-01

    The surrogate reaction method is an indirect way of determining cross sections for nuclear reactions that proceed through a compound nucleus. This technique enables neutron-induced cross sections to be extracted for nuclear reactions on short-lived unstable nuclei that otherwise can not be measured. This technique has been successfully applied to determine the neutron-induced fission cross sections of several short-lived nuclei. In this work, we investigate whether this powerful technique can also be used to determine of neutron-induced capture cross sections. For this purpose we use the surrogate reaction 174 Yb( 3 He, pγ) 176 Lu to infer the well known 175 Lu(n, γ) cross section and compare the results with the directly measured neutron-induced data. This surrogate experiment has been performed in March 2010. The experimental technique used and the first preliminary results will be presented. (authors)

  10. Study on keV-neutron capture cross sections and capture γ-ray spectra of 117,119Sn

    International Nuclear Information System (INIS)

    Nishiyama, J.; Igashira, M.; Ohsaki, T.; Kim, G.N.; Chung, W.C.; Ro, T.I.

    2006-01-01

    The capture cross sections and capture γ-ray spectra of 117,119 Sn were measured in an incident neutron energy region from 10 to 100 keV and at 570 keV, using a 1.5-ns pulsed neutron source by the 7 Li(p,n) 7 Be reaction and a large anti-Compton NaI(Tl) γ-ray spectrometer. A pulse-height weighting technique was applied to observed capture γ-ray pulse-height spectra to derive capture yields. The capture cross sections of 117,119 Sn were obtained with the error of about 5% by using the standard capture cross sections of 197 Au. The present cross sections were compared with previous experimental data and the evaluated values in JENDL-3.3 and ENDF/B-VI. The capture γ-ray spectra of 117,119 Sn were derived by unfolding the observed capture γ-ray pulse-height spectra. The calculations of capture cross sections and capture γ-ray spectra of 117,119 Sn were performed with the EMPIRE-II code. The calculated results were compared with the present experimental ones. (author)

  11. Thermal neutron capture cross sections resonance integrals and g-factors

    International Nuclear Information System (INIS)

    Mughabghab, S.F.

    2003-02-01

    The thermal radiative capture cross sections and resonance integrals of elements and isotopes with atomic numbers from 1 to 83 (as well as 232 Th and 238 U) have been re-evaluated by taking into consideration all known pertinent data published since 1979. This work has been undertaken as part of an IAEA co-ordinated research project on 'Prompt capture gamma-ray activation analysis'. Westcott g-factors for radiative capture cross sections at a temperature of 300K were computed by utilizing the INTER code and ENDF-B/VI (Release 8) library files. The temperature dependence of the Westcott g-factor is illustrated for 113 Cd, 124 Xe and 157 Gd at temperatures of 150, 294 and 400K. Comparisons have also been made of the newly evaluated capture cross sections of 6 Li, 7 Li, 12 C and 207 Pb with those determined by the k 0 method. (author)

  12. Differential cross sections for single-electron capture in He{sup 2+}-D collisions

    Energy Technology Data Exchange (ETDEWEB)

    Bordenave-Montesquieu, D.; Dagnac, R. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France)]|[Toulouse-3 Univ., 31 (France)

    1995-06-14

    A translational energy spectroscopy technique was used to study single-electron capture into the He{sup +} (n = 2) and He{sup +} (n 3) states in He{sup 2+}-D collisions. Differential cross sections were determined at 4, 6 and 8 keV in the angular range 5`-1{sup o}30` (laboratory frame). As expected, single-electron capture into the n = 2 state was found to be the dominant process; total cross sections for capture into the He{sup +} (n = 3) state were compared to other experimental and theoretical results. (author).

  13. Resonance structure of 32S+n from measurements of neutron total and capture cross sections

    International Nuclear Information System (INIS)

    Halperin, J.; Johnson, C.H.; Winters, R.R.; Macklin, R.L.

    1980-01-01

    Neutron total and capture cross sections of 32 S have been measured up to 1100 keV neutron energy [E/sub exc/( 33 S) =9700 keV]. Spin and parity assignments have been made for 28 of the 64 resonances found in this region. Values of total radiation widths, reduced neutron widths, level spacings, and neutron strength functions have been evaluated for s/sub 1/2/, p/sub 1/2/, p/sub 3/2/, and d/sub 5/2/ levels. Single particle contributions using the valency model account for a significant portion of the total radiation width only for the p/sub 1/2/-wave resonances. A significant number of resonances can be identified with reported levels excited in 32 S(d,p) and 29 Si(α,n) reactions. A calculation of the Maxwellian average cross section appropriate to stellar interiors indicates an average capture cross section at 30 keV, sigma-bar approx. = 4.2(2) mb, a result that is relatively insensitive to the assumed stellar temperature. Direct (potential) capture and the s-wave resonance capture contributions to the thermal capture cross section do not fully account for the reported thermal cross section (530 +- 40 mb) and a bound state is invoked to account for the discrepancy

  14. Surface State Capture Cross-Section at the Interface between Silicon and Hafnium Oxide

    Directory of Open Access Journals (Sweden)

    Fu-Chien Chiu

    2013-01-01

    Full Text Available The interfacial properties between silicon and hafnium oxide (HfO2 are explored by the gated-diode method and the subthreshold measurement. The density of interface-trapped charges, the current induced by surface defect centers, the surface recombination velocity, and the surface state capture cross-section are obtained in this work. Among the interfacial properties, the surface state capture cross-section is approximately constant even if the postdeposition annealing condition is changed. This effective capture cross-section of surface states is about 2.4 × 10−15 cm2, which may be an inherent nature in the HfO2/Si interface.

  15. Neutron capture cross section of /sup 197/Au: A standard for stellar nucleosynthesis

    International Nuclear Information System (INIS)

    Ratynski, W.; Kaeppeler, F.

    1988-01-01

    We have measured the neutron capture cross section of gold using the 7 Li(p,n) 7 Be reaction for neutron production. This reaction not only provides the integrated neutron flux via the 7 Be activity of the target, but also allows for the simulation of a Maxwellian neutron energy spectrum at kT = 25 keV. As this spectrum is emitted in a forward cone of 120 0 opening angle, the cross section can be measured in good geometry and independent of any other standard. Systematic uncertainties were studied experimentally in a series of activations. The final stellar cross section at kT = 25 keV was found to be 648 +- 10 mb, and extrapolation to the common s-process temperature kT = 30 keV yields 582 +- 9 mb. This result is used for renormalization of a number of cross sections which had been measured relative to gold

  16. Differential Single-Capture Cross Sections for Fast Alpha–Helium Collisions

    International Nuclear Information System (INIS)

    Ghanbari-Adivi, Ebrahim; Ghavaminia, Hoda

    2014-01-01

    A four-body theoretical study of the single charge transfer process in collision of energetic alpha ions with helium atoms in their ground states is presented. The model utilizes the Coulomb–Born distorted wave approximation with correct boundary conditions to calculate the single-electron capture differential and integral cross sections. The influence of the dynamic and static electron correlations on the capture probability is investigated. The results of the calculations are compared with the recent experimental measurements for differential cross sections and with the other theoretical manipulations. The results for scattering at extreme forward angles are in good agreement with the experimental measurements, but in other scattering angles the agreement is poor. However, the present four-body results for integral cross sections are in excellent agreement with the experimental data. (author)

  17. Thermal neutron capture cross section of gadolinium by pile-oscillation measurements in MINERVE

    International Nuclear Information System (INIS)

    Leconte, P.; Di-Salvo, J.; Antony, M.; Pepino, A.; Hentati, A.

    2012-01-01

    Natural gadolinium is used as a burnable poison in most LWR to account for the excess of reactivity of fresh fuels. For an accurate prediction of the cycle length, its nuclear data and especially its neutron capture cross section needs to be known with a high precision. Recent microscopic measurements at Rensselaer Polytechnic Inst. (RPI) suggest a 11% smaller value for the thermal capture cross section of 157 Gd, compared with most of evaluated nuclear data libraries. To solve this inconsistency, we have analyzed several pile-oscillation experiments, performed in the MINERVE reactor. They consist in the measurement of the reactivity variation involved by the introduction in the reactor of small-samples, containing different mass amounts of natural gadolinium. The analysis of these experiments is done through the exact perturbation theory, using the PIMS calculation tool, in order to link the reactivity effect to the thermal capture cross section. The measurement of reactivity effects is used to deduce the 2200 m.s-1 capture cross section of nat Gd which is (49360 ± 790) b. This result is in good agreement with the JEFF3.1.1 value (48630 b), within 1.6% uncertainty at 1σ, but is strongly inconsistent with the microscopic measurements at RPI which give (44200 ± 500) b. (authors)

  18. Capture cross-section and rate of the 14 C (n, γ) 15 C reaction from ...

    Indian Academy of Sciences (India)

    We calculate the Coulomb dissociation of 15C on a Pb target at 68 MeV/u incident beam energy within the fully quantum mechanical distorted wave Born approximation formalism of breakup reactions. The capture cross-section and the subsequent rate of the 14C(, )15C reaction are calculated from the ...

  19. Thermal neutron capture cross section of gadolinium by pile-oscillation measurements in MINERVE

    Energy Technology Data Exchange (ETDEWEB)

    Leconte, P.; Di-Salvo, J.; Antony, M.; Pepino, A. [CEA, DEN, DER, Cadarache, F-13108 Saint-Paul-Lez-Durance (France); Hentati, A. [International School in Nuclear Engineering, Cadarache, F-13108 Saint-Paul-Lez-Durance (France)

    2012-07-01

    Natural gadolinium is used as a burnable poison in most LWR to account for the excess of reactivity of fresh fuels. For an accurate prediction of the cycle length, its nuclear data and especially its neutron capture cross section needs to be known with a high precision. Recent microscopic measurements at Rensselaer Polytechnic Inst. (RPI) suggest a 11% smaller value for the thermal capture cross section of {sup 157}Gd, compared with most of evaluated nuclear data libraries. To solve this inconsistency, we have analyzed several pile-oscillation experiments, performed in the MINERVE reactor. They consist in the measurement of the reactivity variation involved by the introduction in the reactor of small-samples, containing different mass amounts of natural gadolinium. The analysis of these experiments is done through the exact perturbation theory, using the PIMS calculation tool, in order to link the reactivity effect to the thermal capture cross section. The measurement of reactivity effects is used to deduce the 2200 m.s-1 capture cross section of {sup nat}Gd which is (49360 {+-} 790) b. This result is in good agreement with the JEFF3.1.1 value (48630 b), within 1.6% uncertainty at 1{sigma}, but is strongly inconsistent with the microscopic measurements at RPI which give (44200 {+-} 500) b. (authors)

  20. Simultaneous analysis of fission and capture cross section with Adler-Adler resonance formula

    International Nuclear Information System (INIS)

    Cao Hengdao; Qiu Guochun

    1989-01-01

    The method of simultaneous analysis of fission and capture cross section for fissile nuclide with Adler-Adler resonance formula and the corresponding computer code are presented. A simple and convenient method to correct parameters μ, γ simultaneously is given in order to acquire optimized parameters. The results are satisfactory

  1. Ion-induced ionization and capture cross sections for DNA nucleobases impacted by light ions

    International Nuclear Information System (INIS)

    Champion, Christophe; Hanssen, Jocelyn; Galassi, Mariel E; Fojón, Omar; Rivarola, Roberto D; Weck, Philippe F

    2012-01-01

    Two quantum mechanical models (CB1 and CDW-EIS) are here presented for describing electron ionization and electron capture induced by heavy charged particles in DNA bases. Multiple differential and total cross sections are determined and compared with the scarce existing experimental data.

  2. Adjust of effective cross sections of some actinides in inventory calculation with HAMOR-2

    International Nuclear Information System (INIS)

    Guimaraes, L.N.F.; Marzo, M.A.S.

    1985-01-01

    A comparative study of the adjustment of effective cross sections generated by HAMOR-2 for the following actinides U-238, Pu-239 and Pu-240 is done. The adjustment were made to calculate the inventory of two different PWRs reactors. (M.C.K.) [pt

  3. New Maxwellian averaged neutron capture cross sections for 35,37Cl

    International Nuclear Information System (INIS)

    Guber, K.H.; Sayer, R.O.; Valentine, T.E.; Leal, L.C.; Spencer, R.R.; Harvey, J.A.; Koehler, P.E.; Rauscher, T.

    2002-01-01

    The Oak Ridge Electron Linear Accelerator (ORELA) was used to measure neutron total and capture cross sections of natural chlorine in the energy range from 100 eV to 600 keV. We performed an R-matrix analysis of our new capture and transmission data up to 500 keV. From these resonance parameters new (n,γ) astrophysical reaction rates were determined over the entire energy range needed by the latest stellar models of the s process

  4. Differential cross section measurement of radiative capture of protons by nuclei 12C

    International Nuclear Information System (INIS)

    Burtebayev, N.; Zazulin, D.M.; Buminskii, V.P.; Zarifov, R.A.; Tohtarov, R.N.; Sagindykov, Sh.Sh.; Baktibayev, M.K.

    2003-01-01

    Measurements of differential cross sections of nuclear reaction 12 C(p, γ) 13 N at 0, 45, 90, 135 Deg. to beam direction of flying protons in the field of E p = 350-1100 KeV with an error it is not worse than 10 % have been carried out. Most important was studied, from the astrophysical point of view, process of capture of protons by nucleuses 12 C on the ground state of a nucleus 13 N. It is experimentally shown isotropy of angular distribution of differential cross sections of reaction 12 C(p, γ) 13 N, in the given field energy of protons

  5. UCN anomalous losses and the UCN capture cross section on material defects

    International Nuclear Information System (INIS)

    Serebrov, A.; Romanenko, N.; Zherebtsov, O.; Lasakov, M.; Vasiliev, A.; Fomin, A.; Geltenbort, P.; Krasnoshekova, I.; Kharitonov, A.; Varlamov, V.

    2005-01-01

    Experimental data shows anomalously large ultra cold neutrons (UCN) reflection losses and that the process of UCN reflection is not completely coherent. UCN anomalous losses under reflection cannot be explained in the context of neutron optics calculations. UCN losses by means of incoherent scattering on material defects are considered and cross-section values calculated. The UCN capture cross section on material defects is enhanced by a factor of 10 4 due to localization of UCN around defects. This phenomenon can explain anomalous losses of UCN

  6. Neutron capture cross section of $^{25}$Mg and its astrophysical implications

    CERN Multimedia

    We propose to measure the neutron capture cross section of the stable $^{25}$Mg isotope. This experiment aims at the improvement of existing results for nuclear astrophysics.The measurement will be carried out under similar conditions as for the Mgexperiment that was completed at n_TOF during 2003. A metal $^{25}$Mg-enriched sample will be used in the proposed experiment instead of a MgO powder sample, which was used in the previous measurement and prevented us to minimize the uncertainty of the measured cross section. This experiment will be part of an ongoing study for a comprehensive discussion of the s-process abundances in massive stars.

  7. Kilo-electron-volt neutron capture cross sections of the krypton isotopes

    International Nuclear Information System (INIS)

    Walter, G.; Leugers, B.; Kappeler; Bao, Z.Y.; Reffo, G.; Fabbri, F.

    1986-01-01

    The neutron capture cross sections of the stable krypton isotopes were determined in the energy interval from 4 to 250 keV using a C/sub 6/D/sub 6/-detector system in conjunction with the time-of-flight technique. The energy resolution of the measurement was 4% at 20 keV and 6% at 100 keV, and the experimental uncertainties were typically 6 to 10%. The measurements were complemented by statistical model calculations of all krypton isotopes in the mass range 78 < A < 86 to also obtain reliable cross sections for the unstable nuclei /sup 79,81,85/Kr. These calculations were based on local systematics for all relevant parameters, and the results were estimated to show uncertainties of 20 to 25%. Maxwellian average cross sections were calculated for kT=30 keV

  8. Filtered thermal neutron captured cross sections measurements and decay heat calculations

    International Nuclear Information System (INIS)

    Pham Ngoc Son; Vuong Huu Tan

    2015-01-01

    Recently, a pure thermal neutron beam has been developed for neutron capture measurements based on the horizontal channel No.2 of the research reactor at the Nuclear Research Institute, Dalat. The original reactor neutron spectrum is transmitted through an optimal composition of Bi and Si single crystals for delivering a thermal neutron beam with Cadmium ratio (R ed ) of 420 and neutron flux (Φ th ) of 1.6*10 6 n/cm 2 .s. This thermal neutron beam has been applied for measurements of capture cross sections for nuclide of 51 V, by the activation method relative to the standard reaction 197 Au(n,γ) 198 Au. In addition to the activities of neutron capture cross sections measurements, the study on nuclear decay heat calculations has been also considered to be developed at the Institute. Some results on calculation procedure and decay heat values calculated with update nuclear database for 235 U are introduced in this report. (author)

  9. Neutron capture cross section of $^{90}$Zr Bottleneck in the s-process reaction flow

    CERN Document Server

    Tagliente, G; Milazzo, P M; Moreau, C; Aerts, G; Abbondanno, U; Alvarez, H; Alvarez-Velarde, F; Andriamonje, Samuel A; Andrzejewski, J; Assimakopoulos, Panayiotis; Audouin, L; Badurek, G; Baumann, P; Bečvář, F; Berthoumieux, E; Bisterzo, S; Calviño, F; Calviani, M; Cano-Ott, D; Capote, R; Carrapiço, C; Cennini, P; Chepel, V; Chiaveri, Enrico; Colonna, N; Cortés, G; Couture, A; Cox, J; Dahlfors, M; David, S; Dillman, I; Domingo-Pardo, C; Dridi, W; Durán, I; Eleftheriadis, C; Embid-Segura, M; Ferrant, L; Ferrari, A; Ferreira-Marques, R; Furman, W; Gallino, R; Gonçalves, I; Gonzalez-Romero, E; Gramegna, F; Guerrero, C; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martínez, A; Igashira, M; Jericha, E; Käppeler, F; Kadi, Y; Karadimos, D; Karamanis, D; Kerveno, M; Köhler, P; Kossionides, E; Krtička, M; Lamboudis, C; Leeb, H; Lindote, A; Lopes, I; Lozano, M; Lukic, S; Marganiec, J; Marrone, S; Martínez, T; Massimi, C; Mastinu, P; Mengoni, A; Mosconi, M; Neves, F; Oberhummer, Heinz; O'Brien, S; Pancin, J; Papachristodoulou, C; Papadopoulos, C; Paradela, C; Patronis, N; Pavlik, A; Pavlopoulos, P; Perrot, L; Pigni, M T; Plag, R; Plompen, A; Plukis, A; Poch, A; Praena, J; Pretel, C; Quesada, J; Rauscher, T; Reifarth, R; Rubbia, Carlo; Rudolf, G; Rullhusen, P; Salgado, J; Santos, J; Sarchiapone, L; Savvidis, I; Stéphan, C; Taín, J L; Tassan-Got, L; Tavora, L; Terlizzi, R; Vannini, G; Vaz, P; Ventura, A; Villamarín, D; Vincente, M, C; Vlachoudis, V; Vlastou, R; Voss, F; Walter, S; Wendler, H; Wiescher, M; Wisshak, K

    2008-01-01

    The neutron capture cross sections of the Zr isotopes have important implications in nuclear astrophysics and for reactor design. The small cross section of the neutron magic nucleus 90Zr, which accounts for more than 50% of natural zirconium represents one of the key isotopes for the stellar s-process, because it acts as a bottleneck in the neutron capture chain between the Fe seed and the heavier isotopes. The same element, Zr, also is an important component of the structural materials used in traditional and advanced nuclear reactors. The (n,γ) cross section has been measured at CERN, using the n_TOF spallation neutron source. In total, 45 resonances could be resolved in the neutron energy range below 70 keV, 10 being observed for the first time thanks to the high resolution and low backgrounds at n_TOF. On average, the Γγ widths obtained in resonance analyses with the R-matrix code SAMMY were 15% smaller than reported previously. By these results, the accuracy of the Maxwellian averaged cross section f...

  10. High resolution neutron total and capture cross-sections in separated isotopes of copper (6365Cu)

    International Nuclear Information System (INIS)

    Pandey, M.S.

    1975-01-01

    High resolution neutron total and capture cross section measurements have been performed on separated isotopes of copper ( 63 65 Cu). Measurements for capture cross section were made from about 1 keV to a few hundreds of keV. The total cross section measurements were made in the energy interval of approximately 10 keV to 150 keV. The resulting capture data have been analyzed by a generalized least square peak fitting computer code in the energy interval of 2.5 keV to 50 keV. Photon strengths are determined using the data up to approximately 250 keV. The resulting total cross section data have been analyzed by area-analysis on the transmission values and by R-matrix multilevel code on cross section values. Average s- and p-wave level spacing and s- and p-wave strength function values are determined. From the resonance parameters thus obtained, by the analysis, statistical distribution is studied for s- and p-wave level spacings and reduced neutron widths. A comparison has been made for adjacent level spacings with the theoretical predictions of level repulsion (of same J/sup π/) by Wigner considering levels with various spin states separately for s-wave resonances where confident spin assignment has been possible. Reduced neutron widths are compared with the Porter-Thomas distribution. Optical model formulated by Feshbach, Porter and Weiskopf describes the neutron-nucleus interaction. A comparison has been made between experimentally determined values of the s- and p-wave strength functions and that obtainable from optical model calculations, thereby determining the appropriate optical model parameters. The experimental arrangement, pertinent theoretical discussion, and the processes of data reduction and the analyses along with the comparison of the previously reported results with the present work are presented in detail

  11. 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)

  12. Stellar Neutron Capture Cross Sections of the Lu and Hf Isotopes

    International Nuclear Information System (INIS)

    Wisshak, K.; Voss, F.; Kaeppeler, F.; Kazakov, L.; Krticka, M.

    2005-01-01

    The neutron capture cross sections of 175,176Lu and 176,177,178,179,180Hf have been measured in the energy range from 3 to 225 keV at the Karlsruhe 3.7 MV Van de Graaff accelerator relative to the gold standard. Neutrons were produced by the 7Li(p,n)7Be reaction and capture events were detected by the Karlsruhe 4πBaF2 detector. The cross section ratios could be determined with uncertainties between 0.9 and 1.8% about a factor of five more accurate than previous data. A strong population of isomeric states was found in neutron capture of the Hf isotopes, which are only partially explained by CASINO/GEANT simulations based on the known level schemes.Maxwellian averaged neutron capture cross sections were calculated for thermal energies between kT = 8 keV and 100 keV. Severe differences up to40% were found to the data of a recent evaluation based on existing experimental results. The new data allow for a much more reliable analysis of the important branching in the s-process synthesis path at 176Lu which can be interpreted as an s-process thermometer

  13. Gold standard capture cross section from 100 keV to 15 MeV

    International Nuclear Information System (INIS)

    Ryves, T.B.

    1982-01-01

    The capture cross section of gold is now generally accepted as the principal reference standard, and therefore in this review only gold is considered. Recent measurements of the gold capture cross section in the unresolved region are discussed and compared with the ENDF/B-V evaluation. It is concluded that in the energy interval 100 to 2000 keV the present uncertainty in the evaluation is +-8%, in the interval 2 to 3.5 MeV the uncertainty is +-4%, in ther interval 3.5 to 14 MeV more measurements are needed before a realistic error can be assigned, and from 14 to 15 MeV the uncertainty is +-10%. Several recommendations for future work have been made

  14. Recommended data for capture cross sections in B5+ + H collisions

    International Nuclear Information System (INIS)

    Errea, L F; Guzman, F; Illescas, Clara; Mendez, L; Pons, B; Riera, A; Suarez, J

    2006-01-01

    Recommended values for state selective capture cross sections are presented for the collision B 5+ + H(1s) in the energy range from 0.05 to 1000 keV amu -1 . Special attention is focused on capture processes to n = 7 states of B 4+ , which play an important role in spectral diagnostics in fusion plasmas. In order to completely cover the intermediate impact energy domain, quantal, semi-classical and classical treatments have been employed for low, low-intermediate and intermediate-high energies, respectively. We also give some guidelines about the domain of accuracy of the methodologies employed. Additionally, preliminary cross sections of the B 5+ + H(2s) collision are also provided

  15. The Radiative Capture Cross-Section of U 238 for Fast Neutrons

    International Nuclear Information System (INIS)

    Broda, E.

    1945-01-01

    This report was written by E. Broda and D.H. Wilkinson at the Cavendish Laboratory (Cambridge) in January 1945 and is about the radiative capture cross-section of U238 for fast neutrons. The Chemical procedure and beta counting, the notes on the activation of the samples, the results and an appendix as well as a short introduction can be found in this report. (nowak)

  16. The Radiative Capture Cross-Section of U 238 for Fast Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Broda, E.

    1945-07-01

    This report was written by E. Broda and D.H. Wilkinson at the Cavendish Laboratory (Cambridge) in January 1945 and is about the radiative capture cross-section of U238 for fast neutrons. The Chemical procedure and beta counting, the notes on the activation of the samples, the results and an appendix as well as a short introduction can be found in this report. (nowak)

  17. Cross section measurements of proton capture reactions on Se isotopes relevant to the astrophysical p process

    Science.gov (United States)

    Foteinou, V.; Harissopulos, S.; Axiotis, M.; Lagoyannis, A.; Provatas, G.; Spyrou, A.; Perdikakis, G.; Zarkadas, Ch.; Demetriou, P.

    2018-03-01

    Cross sections of proton capture reactions on 74Se, 78Se, and 80Se have been measured at incident beam energies from 2 to 6 MeV, 1.7 to 3 MeV, and 1.5 to 3.5 MeV, respectively. In the case of Se,8078, cross sections were obtained from in-beam γ -angular distribution measurements, whereas for the 74Se isotope they were derived from off-beam activity measurements. The measured cross sections were compared with calculations performed with the nuclear reaction code talys (version 1.6). A good agreement between theory and experiment was found. Astrophysical S factors and reaction rates deduced from the experimental and calculated cross sections were also compared and the impact of different nuclear ingredients in the calculations on the reaction rates was investigated. It was found that, for certain combinations of nuclear input models, the reaction rates obtained at temperatures relevant to p -process nucleosynthesis differ by a factor 2 at the most, differences that are well within the acceptable deviations of calculated p -nuclei abundances and observations.

  18. Space, energy and anisotropy effects on 238U effective capture cross sections in the resonance region

    International Nuclear Information System (INIS)

    Meftah, B.; Karam, R.A.

    1984-01-01

    Agreement between calculations and measurements within prescribed limits of error is always the test of engineering design analysis. Large and puzzling discrepancies do exist between several measured and calculated important integral reactor parameters. A thorough and exhaustive investigation of the methods used in reactor analysis revealed that in the generation of effective resonance cross sections no anisotropy effects are considered in the resonances. This is true in the integral transport and fundamental-mode codes. The neglect of anisotropy introduces errors at two levels: (1) the effective group cross sections such as σsub(c), σsub(f) and σsub(s); and (2) the diffusion coefficients and P 1 and higher components of the scattering cross sections. The study showed that the inclusion of linear scattering anisotropy increases, in general, the cell effective capture cross section of 238 U in both ZPR-6/5 and TRX-3 reactors. The increase was up to 2% in TRX-3 and 0.5% in ZPR-6/5. The effect on the multiplication factor was -0.003% Δk/k for ZPR-6/5 and -0.05% Δk/k for TRX-3. (author)

  19. Neutron-capture-activation cross sections of 9496Zr and 98100Mo at thermal and 30 keV energy

    International Nuclear Information System (INIS)

    Wyrick, J.M.; Poenitz, W.P.

    1982-01-01

    Neutron-capture cross sections of 94 96 Zr and 98 100 Mo were measured relative to the standard-capture cross section of gold at thermal and 30 keV neutron energies using the activation technique. The reported values are based upon available decay-scheme information

  20. Partial neutron capture cross sections of actinides using cold neutron prompt gamma activation analysis

    International Nuclear Information System (INIS)

    Genreith, Christoph

    2015-01-01

    Nuclear waste needs to be characterized for its safe handling and storage. In particular long-lived actinides render the waste characterization challenging. The results described in this thesis demonstrate that Prompt Gamma Neutron Activation Analysis (PGAA) with cold neutrons is a reliable tool for the non-destructive analysis of actinides. Nuclear data required for an accurate identification and quantification of actinides was acquired. Therefore, a sample design suitable for accurate and precise measurements of prompt γ-ray energies and partial cross sections of long-lived actinides at existing PGAA facilities was presented. Using the developed sample design the fundamental prompt γ-ray data on 237 Np, 241 Am and 242 Pu were measured. The data were validated by repetitive analysis of different samples at two individual irradiation and counting facilities - the BRR in Budapest and the FRM II in Garching near Munich. Employing cold neutrons, resonance neutron capture by low energetic resonances was avoided during the experiments. This is an improvement over older neutron activation based works at thermal reactor neutron energies. 152 prompt γ-rays of 237 Np were identified, as well as 19 of 241 Am, and 127 prompt γ-rays of 242 Pu. In all cases, both high and lower energetic prompt γ-rays were identified. The most intense line of 237 Np was observed at an energy of E γ =182.82(10) keV associated with a partial capture cross section of σ γ =22.06(39) b. The most intense prompt γ-ray lines of 241 Am and of 242 Pu were observed at E γ =154.72(7) keV with σ γ =72.80(252) b and E γ =287.69(8) keV with σ γ =7.07(12) b, respectively. The measurements described in this thesis provide the first reported quantifications on partial radiative capture cross sections for 237 Np, 241 Am and 242 Pu measured simultaneously over the large energy range from 45 keV to 12 MeV. Detailed uncertainty assessments were performed and the validity of the given uncertainties was

  1. 12C+16O sub-barrier radiative capture cross-section measurements

    International Nuclear Information System (INIS)

    Goasduff, A.; Courtin, S.; Haas, F.; Beck, C.; Lebhertz, D.; Jenkins, D.G.; Fallis, J.; Ruiz, C.; Hutcheon, D.A.; Amandruz, P.A.; Davis, C.; Hager, U.; Ottewell, D.; Ruprecht, G.

    2011-01-01

    We have performed a heavy ion radiative capture reaction between two light heavy ions, 12 C and 16 O, leading to 28 Si. The present experiment has been performed below Coulomb barrier energies in order to reduce the phase space and to try to shed light on structural effects. Obtained γ-spectra display a previously unobserved strong feeding of intermediate states around 11 MeV at these energies. This new decay branch is not fully reproduced by statistical nor semi-statistical decay scenarios and may imply structural effects. Radiative capture cross-sections are extracted from the data. (authors)

  2. Differential cross section measurement of radiative capture of protons by nuclei 13C

    International Nuclear Information System (INIS)

    Baktibayev, M.K.; Burminskii, V.P.; Burtebayev, N.; Jazairov-Kakhramanov, V.; Kadyrzhanov, K.K.; Sagindykov, Sh.Sh.; Zarifov, R.A.; Zazulin, D.M.

    2004-01-01

    The reaction 13 C(p,γ ) 14 N is the important one for the astrophysics, not only for nuclear synthesis of CNO elements, but also for nuclear synthesis of elements participating in subsequent combustion of helium [1]. The predominant yield of the reaction occurs at protons energies of less than 1 MeV. However, the clearness of the capture mechanism in this energy region is made difficult because of the superposition of the contribution of the low - energy part of the resonance 1320 keV onto the cross section. Last experimental data for a wider energy region, informed in the work [1], and results of previous works, mentioned in that work, give reason for further continuation of the study of the reaction 13 C(p,γ ) 14 N. Measured data of the work [1] in the region of E P = (320 - 900) keV at the angles of 0 o and 90 o are obviously insufficient. In the present work measurements of differential cross sections of the reaction were carried out at protons energies E P = 991 - 365 keV, the accuracy is not worse than 10%. There was studied the most (from the astrophysical point of view) important process of protons capture by 13 C nuclei onto the ground state of the 14 N nucleus. The theoretical investigation of the given reaction included calculation of cross sections. The cross sections were calculated within the framework of model of direct capture with the using of optical potentials for the description of a channel of scattering. The wave functions of a bound state were generated in a potential reproducing binding energy of a proton in 14 N nucleus. Results of calculations were compared with the experimental data. (author)

  3. ORACLE: an adjusted cross-section and covariance library for fast-reactor analysis

    International Nuclear Information System (INIS)

    Yeivin, Y.; Marable, J.H.; Weisbin, C.R.; Wagschal, J.J.

    1980-01-01

    Benchmark integral-experiment values from six fast critical-reactor assemblies and two standard neutron fields are combined with corresponding calculations using group cross sections based on ENDF/B-V in a least-squares data adjustment using evaluated covariances from ENDF/B-V and supporting covariance evaluations. Purpose is to produce an adjusted cross-section and covariance library which is based on well-documented data and methods and which is suitable for fast-reactor design. By use of such a library, data- and methods-related biases of calculated performance parameters should be reduced and uncertainties of the calculated values minimized. Consistency of the extensive data base is analyzed using the chi-square test. This adjusted library ORACLE will be available shortly

  4. Neutron Capture Cross Section of Unstable Ni63: Implications for Stellar Nucleosynthesis

    Science.gov (United States)

    Lederer, C.; Massimi, C.; Altstadt, S.; Andrzejewski, J.; Audouin, L.; Barbagallo, M.; Bécares, V.; Bečvář, F.; Belloni, F.; Berthoumieux, E.; Billowes, J.; Boccone, V.; Bosnar, D.; Brugger, M.; Calviani, M.; Calviño, F.; Cano-Ott, D.; Carrapiço, C.; Cerutti, F.; Chiaveri, E.; Chin, M.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Diakaki, M.; Domingo-Pardo, C.; Duran, I.; Dressler, R.; Dzysiuk, N.; Eleftheriadis, C.; Ferrari, A.; Fraval, K.; Ganesan, S.; García, A. R.; Giubrone, G.; Gómez-Hornillos, M. B.; Gonçalves, I. F.; González-Romero, E.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Gurusamy, P.; Jenkins, D. G.; Jericha, E.; Kadi, Y.; Käppeler, F.; Karadimos, D.; Kivel, N.; Koehler, P.; Kokkoris, M.; Korschinek, G.; Krtička, M.; Kroll, J.; Langer, C.; Leeb, H.; Leong, L. S.; Losito, R.; Manousos, A.; Marganiec, J.; Martínez, T.; Mastinu, P. F.; Mastromarco, M.; Meaze, M.; Mendoza, E.; Mengoni, A.; Milazzo, P. M.; Mingrone, F.; Mirea, M.; Mondelaers, W.; Paradela, C.; Pavlik, A.; Perkowski, J.; Pignatari, M.; Plompen, A.; Praena, J.; Quesada, J. M.; Rauscher, T.; Reifarth, R.; Riego, A.; Roman, F.; Rubbia, C.; Sarmento, R.; Schillebeeckx, P.; Schmidt, S.; Schumann, D.; Tagliente, G.; Tain, J. L.; Tarrío, D.; Tassan-Got, L.; Tsinganis, A.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Versaci, R.; Vermeulen, M. J.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Ware, T.; Weigand, M.; Weiß, C.; Wright, T. J.; Žugec, P.

    2013-01-01

    The Ni63(n,γ) cross section has been measured for the first time at the neutron time-of-flight facility n_TOF at CERN from thermal neutron energies up to 200 keV. In total, capture kernels of 12 (new) resonances were determined. Maxwellian averaged cross sections were calculated for thermal energies from kT=5-100keV with uncertainties around 20%. Stellar model calculations for a 25M⊙ star show that the new data have a significant effect on the s-process production of Cu63, Ni64, and Zn64 in massive stars, allowing stronger constraints on the Cu yields from explosive nucleosynthesis in the subsequent supernova.

  5. Thermal neutron radiative capture cross-section of 186W(n, γ)187W reaction

    International Nuclear Information System (INIS)

    Tan, V H; Son, P N

    2016-01-01

    The thermal neutron radiative capture cross section for 186 W(n, γ) 187 W reaction was measured by the activation method using the filtered neutron beam at the Dalat research reactor. An optimal composition of Si and Bi, in single crystal form, has been used as neutron filters to create the high-purity filtered neutron beam with Cadmium ratio of R cd = 420 and peak energy E n = 0.025 eV. The induced activities in the irradiated samples were measured by a high resolution HPGe digital gamma-ray spectrometer. The present result of cross section has been determined relatively to the reference value of the standard reaction 197 Au(n, γ) 198 Au. The necessary correction factors for gamma-ray true coincidence summing, and thermal neutron self-shielding effects were taken into account in this experiment by Monte Carlo simulations. (paper)

  6. Specifications for adjusted cross section and covariance libraries based upon CSEWG fast reactor and dosimetry benchmarks

    International Nuclear Information System (INIS)

    Weisbin, C.R.; Marable, J.H.; Collins, P.J.; Cowan, C.L.; Peelle, R.W.; Salvatores, M.

    1979-06-01

    The present work proposes a specific plan of cross section library adjustment for fast reactor core physics analysis using information from fast reactor and dosimetry integral experiments and from differential data evaluations. This detailed exposition of the proposed approach is intended mainly to elicit review and criticism from scientists and engineers in the research, development, and design fields. This major attempt to develop useful adjusted libraries is based on the established benchmark integral data, accurate and well documented analysis techniques, sensitivities, and quantified uncertainties for nuclear data, integral experiment measurements, and calculational methodology. The adjustments to be obtained using these specifications are intended to produce an overall improvement in the least-squares sense in the quality of the data libraries, so that calculations of other similar systems using the adjusted data base with any credible method will produce results without much data-related bias. The adjustments obtained should provide specific recommendations to the data evaluation program to be weighed in the light of newer measurements, and also a vehicle for observing how the evaluation process is converging. This report specifies the calculational methodology to be used, the integral experiments to be employed initially, and the methods and integral experiment biases and uncertainties to be used. The sources of sensitivity coefficients, as well as the cross sections to be adjusted, are detailed. The formulae for sensitivity coefficients for fission spectral parameters are developed. A mathematical formulation of the least-square adjustment problem is given including biases and uncertainties in methods

  7. Filtered thermal neutron captured cross-sections measurements and decay heat calculations

    International Nuclear Information System (INIS)

    Son, Pham Ngoc; Tan, Vuong Huu

    2014-01-01

    Recently, a pure thermal neutron beam has been developed for neutron capture measurements based on the horizontal channel No.2 of the research reactor at the Nuclear Research Institute, Dalat. The original reactor neutron spectrum is transmitted through an optimal composition of Bi and Si single crystals for delivering a thermal neutron beam with Cadmium ratio (R cd ) of 420 and neutron flux (Φ th ) of 1.6x10 6 n/cm 2 .s. This thermal neutron beam has been applied for measurements of capture cross-sections for nuclide of 51 V, 55 Mn, 180 Hf and 186 W by the activation method relative to the standard reaction 197 Au(n,g) 198 Au. In addition to the activities of neutron capture cross-sections measurements, the study on nuclear decay heat calculations has been also considered to be developed at the Institute. Some results on calculation procedure and decay heat values calculated with update nuclear database for 235 U, 238 U, 239 Pu and 232 Th are introduced in this report. (author)

  8. Measurements and analysis of the 127I and 129I neutron capture and total cross sections

    International Nuclear Information System (INIS)

    Noguere, G.

    2005-01-01

    Most of the experimental work on the interaction of neutrons with matter has focused on materials important to reactor physics and reactor structures. By comparison, the corresponding data for minor actinides or long-lived fission products are poor. A significant demand has developed for improved neutron cross-section data of these little-studied nuclides due to the surge of interest in the transmutation of nuclear waste. With 400 kg of 129 I produced yearly in the reactors of the EU countries and a very long β - half-life of 1.57 x 10 7 years, iodine requires disposal strategies that will isolate this isotope from the environment for long periods of time. Therefore, 129 I is potentially a key long-lived fission product for transmutation applications, since 129 I transmutes in 130 I after a single neutron capture and decays to 130 Xe with a 12.36 h half-life. Accurate capture cross sections would help to reduce uncertainties in waste management concepts. For that purpose, Time-Of-Flight measurements covering the [0.5 eV-100 keV] energy range have been carried out at the 150 MeV pulsed neutron source GELINA of the Institute for Reference Materials and Measurements (IRMM). Two types of experiments have been performed at the IRMM, namely capture and transmission experiments. They are respectively related to the neutron capture and total cross sections. Since the PbI 2 samples used in this work contain natural and radioactive iodine, extensive measurements of 129 I have been carried out under the same experimental conditions as for the 129 I. The data reduction process was performed with the AGS system, and the resonance parameters were extracted with the SAMMY and REFIT shape analysis codes. In a last step, the parameters have been converted into ENDF-6 format and processed with the NJOY code to produce point-wise and multigroup cross sections, as well as MCNP and ERANOS libraries. (author)

  9. Single electron capture differential cross section in H+ + He collisions at intermediate and high collision energies

    International Nuclear Information System (INIS)

    Abufager, P N; Fainstein, P D; MartInez, A E; Rivarola, R D

    2005-01-01

    The generalized continuum distorted wave-eikonal initial state (CDW-EIS II) approximation is employed to study differential cross sections (DCS) for single electron capture in H + + He collisions at intermediate and high energies. Present results are compared with theoretical calculations obtained using the previous CDW-EIS formulation in order to show the importance of the description of the bound and continuum target states in the entrance and exit channels, respectively. Both DCS are also shown together with other theoretical results and with experimental data

  10. Absorption and activation techniques in measurements of fast-neutron capture cross sections

    International Nuclear Information System (INIS)

    Bergqvist, I.

    1982-01-01

    The absorption and activation methods have been applied for a long time to systematic studies of fast neutron capture cross sections. Both methods are simple in principle but difficult in practice. The simplicity should ensure a wider use of the methods in particular for problems which may be complicated to approach with other methods. The difficulties encountered in absorption measurements are related to multiple scattering and resonance shielding effects. In activation experiments the influence of secondary low-energy neutrons causes the main problems

  11. Aborption and activation techniques in measurements of fast-neutron capture cross sections

    International Nuclear Information System (INIS)

    Bergqvist, I.

    1982-01-01

    The absorption and activation methods have been applied for a long time to systematic studies of fast neutron capture cross sections. Both methods are simple in principle but difficult in practice. The simplicity should ensure a wider use of the methods in particular for problems which may be complicated to approach with other methods The difficulties encountered in absorption measurements are related to multiple scattering and resonance shielding effects. In activation experiments the influence of secondary low-energy neutrons c causes the main problems. (Author)

  12. The Cross-Section for the Radiative Capture of Thermal Neutrons by Uranium

    Energy Technology Data Exchange (ETDEWEB)

    Broda, E.

    1942-07-01

    This report is based on an experiment performed at the Cavendish Laboratory (Cambridge) by E. Broda, J. Guéron and L. Kowarski in July 1942 where the intensity of the beta-activity induced in uranium by thermal neutrons has been compared with that induced in manganese or iodine. Care was taken to avoid losses due to a Szilard-Chalmers effect. The capture cross section of uranium for thermal neutrons is found to amount to (2.78 ±0.1)*10{sup -24} cm{sup 2}, assuming the value 581*10{sup -24} cm{sup 2} for σ{sub B}. (nowak)

  13. A Cross-Section Adjustment Method for Double Heterogeneity Problem in VHTGR Analysis

    International Nuclear Information System (INIS)

    Yun, Sung Hwan; Cho, Nam Zin

    2011-01-01

    Very High Temperature Gas-Cooled Reactors (VHTGRs) draw strong interest as candidates for a Gen-IV reactor concept, in which TRISO (tristructuralisotropic) fuel is employed to enhance the fuel performance. However, randomly dispersed TRISO fuel particles in a graphite matrix induce the so-called double heterogeneity problem. For design and analysis of such reactors with the double heterogeneity problem, the Monte Carlo method is widely used due to its complex geometry and continuous-energy capabilities. However, its huge computational burden, even in the modern high computing power, is still problematic to perform wholecore analysis in reactor design procedure. To address the double heterogeneity problem using conventional lattice codes, the RPT (Reactivityequivalent Physical Transformation) method considers a homogenized fuel region that is geometrically transformed to provide equivalent self-shielding effect. Another method is the coupled Monte Carlo/Collision Probability method, in which the absorption and nu-fission resonance cross-section libraries in the deterministic CPM3 lattice code are modified group-wise by the double heterogeneity factors determined by Monte Carlo results. In this paper, a new two-step Monte Carlo homogenization method is described as an alternative to those methods above. In the new method, a single cross-section adjustment factor is introduced to provide self-shielding effect equivalent to the self-shielding in heterogeneous geometry for a unit cell of compact fuel. Then, the homogenized fuel compact material with the equivalent cross-section adjustment factor is used in continuous-energy Monte Carlo calculation for various types of fuel blocks (or assemblies). The procedure of cross-section adjustment is implemented in the MCNP5 code

  14. Differential cross section measurement of radiative capture of protons by nuclei 13C

    International Nuclear Information System (INIS)

    Baktibayev, M.K.; Burminskii, V.P.; Burtebayev, N.; Dzazairov-Kakhramanov, V.; Kadyrzhanov, K.K.; Sagindykov, Sh.Sh.; Zarifov, R.A.; Zazulin, D.M.

    2004-01-01

    Full text: The reaction 13 C(p,γ ) 14 N is the important one for the astrophysics, not only for nuclear synthesis of CNO elements, but and for nuclear synthesis of elements participating in subsequent combustion of helium [1]. The predominant yield of the reaction occurs at protons energies of less than 1 MeV. However, the clearness of the capture mechanism in this energy region is made difficult because of the superposition of the contribution of the low - energetical part of the resonance 1320 keV onto the cross section. Last experimental data for more wide energy region, informed in the work [1], and results of previous works, mentioned in that work, give reason for further continuation of the study of the reaction 13 C(p,γ ) 14 N. Measured data of the work [1] in the region of E ρ = (320 † 900) keV at the angles of 0 o and 90 o are obviously insufficient. In the present work measurements of differential cross sections of the reaction were carried out at protons energies E p = 991, 558 and 365 keV, the accuracy is not worse then 10%. There was studied the most (from the astrophysical point of view) important process of protons capture by 13 C nuclei onto the ground state of the 14 N nucleus. The 13 C (99%) targets, used in the experiment, were sprayed onto copper base. The target thickness was determined by incident protons energy losses in the target. The energy losses were clearly reflected in the corresponding spreading of transitions of radiation capture. The statement about the gamma-lines spreading is valid in this case, because energy losses in the target are here significantly more, than the energetical resolution of the detector. The peak width of the radiation capture gamma-line at half-height corresponds to energy losses of incident protons in the target. From the Table of brake values for protons in carbon [2] there was determined that the thickness of the target was 140 ± 5% μg/cm 2 . The upper part of gamma-lines in the spectrum repeats the

  15. High-resolution neutron capture and transmission measurements and the stellar neutron capture cross sections of 116,120Sn

    International Nuclear Information System (INIS)

    Koehler, P.E.; Spencer, R.R.; Guber, K.H.

    1997-01-01

    Improved astrophysical reaction rates for 116,120 Sn(n, γ) are of interest because nucleosynthesis models have not been able to reproduce the observed abundances in this mass region. For example, previous s-process calculations have consistently underproduced the s-only isotope 116 Sn. Also, these studies have resulted in residual reprocess abundances for the tin isotopes which are systematically larger than predicted by reprocess calculations. It has been suggested that these problems could be solved by reducing the solar tin abundance by 10-20%, but there is no experimental evidence to justify this renormalization. Instead, it is possible that the problem lies in the (n,T) cross sections used in the reaction network calculations or in the s-process models. One reason to suspect the (n, γ) data is that previous measurements did not extend to low enough energies to determine accurately the Maxwellian-averaged capture cross sections at the low temperatures (kT=6-8 keV) favored by the most recent stellar models of the s process. Also, the two most recent high-precision measurements of the 120 Sn(n, γ) cross section are in serious disagreement. Because of its small size, this cross section could affect (via the s-process branching at 121 Sn) the relative abundances of the three s-only isotopes of Te

  16. Evaluation of the capture cross section of natural Ti from 10-5eV to 20.106eV

    International Nuclear Information System (INIS)

    Simon, G.; Bersillon, O.; Mosinski, G.; Philis, C.; Trochon, J.; Verges, N.

    1977-01-01

    In the 10 -5 eV - 200 keV energy range a coherent resolved resonance parameter set has been determined for each titanium isotope. From these sets the titanium capture cross section has been calculated with the Reich-Moore formalism and corrected for the missing resonances. From 200 keV up to 20 MeV all the isotopic cross sections were calculated with the help of two statistical model codes NCNR and FISPRO. These calculations have been adjusted on available 50 Ti(n,γ) 51 Ti and Ti(n,γ) experimental results. The elemental titanium capture cross section has been obtained as the weighted sum of the isotopic cross sections. The present evaluation is descriptive of the experimental values. The comparison of the present evaluation with ENDF/BIV shows the ameliorations brought in this cross section: a better description of all the resonances known in the 1 keV - 200 keV energy range; above 200 keV the new data give a more realistic shape showing compound nucleus competition of prominent inelastic scattering channels. As titanium is used as structural material for fast reactors the capture cross section integrals for the two evaluations in different energy ranges are compared. These comparisons show considerable discrepancies in some areas. Thus the new evaluation may change the results of reactor calculations

  17. A methodology to leverage cross-sectional accelerometry to capture weather's influence in active living research.

    Science.gov (United States)

    Katapally, Tarun R; Rainham, Daniel; Muhajarine, Nazeem

    2016-06-27

    While active living interventions focus on modifying urban design and built environment, weather variation, a phenomenon that perennially interacts with these environmental factors, is consistently underexplored. This study's objective is to develop a methodology to link weather data with existing cross-sectional accelerometry data in capturing weather variation. Saskatoon's neighbourhoods were classified into grid-pattern, fractured grid-pattern and curvilinear neighbourhoods. Thereafter, 137 Actical accelerometers were used to derive moderate to vigorous physical activity (MVPA) and sedentary behaviour (SB) data from 455 children in 25 sequential one-week cycles between April and June, 2010. This sequential deployment was necessary to overcome the difference in the ratio between the sample size and the number of accelerometers. A data linkage methodology was developed, where each accelerometry cycle was matched with localized (Saskatoon-specific) weather patterns derived from Environment Canada. Statistical analyses were conducted to depict the influence of urban design on MVPA and SB after factoring in localized weather patterns. Integration of cross-sectional accelerometry with localized weather patterns allowed the capture of weather variation during a single seasonal transition. Overall, during the transition from spring to summer in Saskatoon, MVPA increased and SB decreased during warmer days. After factoring in localized weather, a recurring observation was that children residing in fractured grid-pattern neighbourhoods accumulated significantly lower MVPA and higher SB. The proposed methodology could be utilized to link globally available cross-sectional accelerometry data with place-specific weather data to understand how built and social environmental factors interact with varying weather patterns in influencing active living.

  18. Measurement of the radiative neutron capture cross section of 206Pb and its astrophysical implications

    CERN Document Server

    Domingo-Pardo, C.; Aerts, G.; Alvarez, H.; Alvarez-Velarde, F.; Andriamonje, S.; Andrzejewski, J.; Assimakopoulos, P.; Audouin, L.; Badurek, G.; Baumann, P.; Becvar, F.; Berthoumieux, E.; Bisterzo, S.; Calvino, F.; Calviani, M.; Cano-Ott, D.; Capote, R.; Carrapico, C.; Cennini, P.; Chepel, V.; Chiaveri, E.; Colonna, N.; Cortes, G.; Couture, A.; Cox, J.; Dahlfors, M.; David, S.; Dillman, I.; Dolfini, R.; Dridi, W.; Duran, I.; Eleftheriadis, C.; Embid-Segura, M.; Ferrant, L.; Ferrari, A.; Ferreira-Marques, R.; Fitzpatrick, L.; Frais-Koelbl, H.; Fujii, K.; Furman, W.; Gallino, R.; Goncalves, I.; Gonzalez-Romero, E.; Goverdovski, A.; Gramegna, F.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Haas, B.; Haight, R.; Heil, M.; Herrera-Martinez, A.; Igashira, M.; Isaev, M.; Jericha, E.; Kappeler, F.; Kadi, Y.; Karadimos, D.; Karamanis, D.; Kerveno, M.; Ketlerov, V.; Koehler, P.; Konovalov, V.; Kossionides, E.; Krticka, M.; Lamboudis, C.; Leeb, H.; Lindote, A.; Lopes, I.; Lozano, M.; Lukic, S.; Marganiec, J.; Marrone, S.; Massimi, C.; Mastinu, P.; Mengoni, A.; Milazzo, P.M.; Moreau, C.; Mosconi, M.; Neves, F.; Oberhummer, H.; Oshima, M.; O'Brien, S.; Pancin, J.; Papachristodoulou, C.; Papadopoulos, C.; Paradela, C.; Patronis, N.; Pavlik, A.; Pavlopoulos, P.; Perrot, L.; Plag, R.; Plompen, A.; Plukis, A.; Poch, A.; Pretel, C.; Quesada, J.; Rauscher, T.; Reifarth, R.; Rosetti, M.; Rubbia, C.; Rudolf, G.; Rullhusen, P.; Salgado, J.; Sarchiapone, L.; Savvidis, I.; Stephan, C.; Tagliente, G.; Tain, J.L.; Tassan-Got, L.; Tavora, L.; Terlizzi, R.; Vannini, G.; Vaz, P.; Ventura, A.; Villamarin, D.; Vincente, M.C.; Vlachoudis, V.; Vlastou, R.; Voss, F.; Walter, S.; Wendler, H.; Wiescher, M.; Wisshak, K.

    2007-01-01

    The (n, gamma) cross section of 206Pb has been measured at the CERN n_TOF facility with high resolution in the energy range from 1 eV to 600 keV by using two optimized C6D6 detectors. In the investigated energy interval about 130 resonances could be observed, from which 61 had enough statistics to be reliably analyzed via the R-matrix analysis code SAMMY. Experimental uncertainties were minimized, in particular with respect to (i) angular distribution effects of the prompt capture gamma-rays, and to (ii) the TOF-dependent background due to sample-scattered neutrons. Other background components were addressed by background measurements with an enriched 208Pb sample. The effect of the lower energy cutoff in the pulse height spectra of the C6D6 detectors was carefully corrected via Monte Carlo simulations. Compared to previous 206Pb values, the Maxwellian averaged capture cross sections derived from these data are about 20% and 9% lower at thermal energies of 5 keV and 30 keV, respectively. These new results hav...

  19. The neutron capture cross section of the ${s}$-process branch point isotope $^{63}$Ni

    CERN Multimedia

    Neutron capture nucleosynthesis in massive stars plays an important role in Galactic chemical evolution as well as for the analysis of abundance patterns in very old metal-poor halo stars. The so-called weak ${s}$-process component, which is responsible for most of the ${s}$ abundances between Fe and Sr, turned out to be very sensitive to the stellar neutron capture cross sections in this mass region and, in particular, of isotopes near the seed distribution around Fe. In this context, the unstable isotope $^{63}$Ni is of particular interest because it represents the first branching point in the reaction path of the ${s}$-process. We propose to measure this cross section at n_TOF from thermal energies up to 500 keV, covering the entire range of astrophysical interest. These data are needed to replace uncertain theoretical predicitons by first experimental information to understand the consequences of the $^{63}$Ni branching for the abundance pattern of the subsequent isotopes, especially for $^{63}$Cu and $^{...

  20. Non-statistical effects in the radiative capture cross sections of the neodymium isotopes

    International Nuclear Information System (INIS)

    Musgrove, A.R.; Allen, B.J.; Boldeman, J.W.

    1977-01-01

    The neutron capture cross sections of the stable neodymium isotopes have been measured with high energy resolution in the keV region at the 40 m station of ORELA. Average resonance parameters are extracted for s-wave resonances. Significant positive correlations are found between gamma-n-0 and gamma-gamma for all isotopes. The magnitude of the observed correlation coefficient, particularly for 142 Nd (rho = 0.9), cannot be explained in terms of valence neutron capture and additional mechanisms are discussed. The average s-wave radiative widths for the odd-A isotopes are markedly greater than for the even-A isotopes, while the p-wave radiative width for 142 Nd is considerably less than the s-wave width. (author)

  1. Factors influencing adjustment to a colostomy in Chinese patients: a cross-sectional study.

    Science.gov (United States)

    Hu, Ailing; Pan, Yunfeng; Zhang, Meifen; Zhang, June; Zheng, Meichun; Huang, Manrong; Ye, Xinmei; Wu, Xianrong

    2014-01-01

    We evaluated persons living with a colostomy in order to characterize and describe relationships among adjustment, self-care ability, and social support. One hundred twenty-nine colostomy patients from 5 hospitals in Guangzhou, capital city of the Guangdong province, were recruited by convenience sampling. Cross-sectional data were collected from a survey that included demographic and pertinent clinical data related to their ostomy. The survey also incorporated Chinese language versions of the Ostomy Adjustment Scale, Exercise of Self-Care Agency Scale, and Perceived Social Support Scale. These scales were used to measure the levels and degrees of adjustment, self-care ability, and social support of colostomy patients. Respondents completed the survey during outpatient clinics visit after creation of a colostomy. Scores from the Ostomy Adjustment Scale revealed that 96.9% of colostomy patients reported low to moderate adjustment (128.6 ± 19.38) to their stoma. Self-care ability and social support of patients were positively correlated with the adjustment level (R = 0.33, R = 0.21). Several factors, including being a housewife, paying medical expense by oneself, inability to manage the ostomy without assistance, and not participating in an ostomy support group, were associated with a lower level of adjustment (P colostomy was moderate. Self-care ability and social support associated with having a colostomy positively influenced adjustment. Adjustment was also influenced by occupation, health insurance provider, and ability to care for the stoma without requiring assistance.

  2. Calculation of homogenized Pickering NGS stainless steel adjuster rod neutron cross-sections using conservation of reaction rates

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, R C [Atlantic Nuclear Services Ltd. (Canada); Tran, F [Ontario Hydro, Pickering, ON (Canada). Pickering Generating Station

    1996-12-31

    A homogenization methodology for calculation of reactivity device incremental cross-sections has been developed using reaction rate conservation (RRC). A heterogeneous transport calculation of flux was utilised to produce the homogenized cross-sections for a finite difference two group diffusion code. The RRC cross-sections have been shown to improve significantly the prediction of reactivity worth for stainless steel adjuster rods installed in Pickering NGS reactors. (author). 10 refs., 3 tabs., 6 figs.

  3. Photoneutron cross sections measurements in 9Be, 13C e 17O with thermal neutron capture gamma-rays

    International Nuclear Information System (INIS)

    Semmler, Renato

    2006-01-01

    Photoneutron cross sections measurements of 9 Be, 13 C and 17 O have been obtained in the energy interval between 1,6 and 10,8 MeV, using neutron capture gamma-rays with high resolution in energy (3 a 21 eV), produced by 21 target materials, placed inside a tangential beam port, near the core of the IPEN/CNEN-SP IEA-R1 (5 MW) research reactor. The samples have been irradiated inside a 4π geometry neutron detector system 'Long Counter', 520,5 cm away from the capture target. The capture gamma-ray flux was determined by means of the analysis of the gamma spectrum obtained by using a Ge(Li) solid-state detector (EG and G ORTEC, 25 cm 3 , 5%), previously calibrated with capture gamma-rays from a standard target of Nitrogen (Melamine). The neutron photoproduction cross section has been measured for each target capture gamma-ray spectrum (compound cross section). A inversion matrix methodology to solve inversion problems for unfolding the set of experimental compound cross sections, was used in order to obtain the cross sections at specific excitation energy values (principal gamma line energies of the capture targets). The cross sections obtained at the energy values of the principal gamma lines were compared with experimental data reported by other authors, with have employed different gamma-ray sources. A good agreement was observed among the experimental data in this work with reported in the literature. (author)

  4. Actinide Capture and Fission Cross Section Measurements Within the Mini-Inca Project

    International Nuclear Information System (INIS)

    Letourneau, A.

    2006-01-01

    Full text of publication follows: The Mini-INCA project is devoted to precise description of the transmutation chain of Actinides within high thermal neutron fluxes. It uses the High Flux Reactor of ILL (Laue Langevin Institute) as an intense thermal neutron source to measure capture and fission cross sections. Two irradiation channels are dedicated for those measurements offering a diversity of fluxes ranging from pure thermal neutrons to 15% epithermal neutrons with intensities as high as 1*10 15 n/cm 2 /s. Standard nuclear techniques for measurements, such as α and γ-spectroscopy of irradiated samples, have been extended in order to stand all constraints due to the irradiation in high fluxes. In particular new types of fission micro-chambers have been developed to follow online the evolution of one actinide and to measure its fission cross section in reference to 235 U(n,F) standard reaction. This type of neutron detector will be used within the MEGAPIE target to on-line characterise the neutron flux and to study the potentiality of such target in terms of incineration. (author)

  5. Response of Moxon-Rae type gamma detectors for neutron capture cross section measurements

    International Nuclear Information System (INIS)

    Iyengar, K.V.K.; Lal, B.; Jhingan, M.L.

    1974-01-01

    A detector devised by Moxon and Rae for the absolute measurement of (n,γ) cross sections is briefly described. This detector is supposed to have an efficiency per MeV of γ-ray energy independent of the energy of the γ-rays. Such a detector consists of an electron converter placed before a thin plastic scintillator which detects the electron emitted by interaction of the γ-ray in the converter. The performance of this type of detector depends on the thickness and composition of the converter. Detailed Monte-Carlo calculations of the response for γ-ray energies from 0.2 to 12 MeV has been carried out for elements ranging from C to Bi and for a mixture of elements as well as for a mixture of an element plus compound, to find out the suitable material and thickness of the converter. Among the elements studied for the converter, Ni, Mo and Sn have a uniform response over the photon energy range 1-12 MeV. Out of these elements Mo has a low neutron capture cross section in the energy range 1-1000 keV and is thus to be preferred. A mixture of C + Bi 2 O 3 in the weight ratio 11.6 : 88.4 gives a uniform response over the photon energy range 1-12 MeV. (K.B.)

  6. Neutron capture cross sections of $^{70,72,73,74,76}$ Ge at n_TOF EAR-1

    CERN Multimedia

    We propose to measure the (n;$\\gamma$ ) cross sections of the isotopes $^{70;72;73;74;76}$Ge. Neutron induced reactions on Ge are of importance for the astrophysical slow neutron capture process, which is responsible for forming about half of the overall elemental abundances heavier than Fe. The neutron capture cross section on Ge affects the abundances produced in this process for a number of heavier isotopes up to a mass number of A = 90. Additionally, neutron capture on Ge is of interest for low background experiments involving Ge detectors. Experimental cross section data presently available for Ge (n;$\\gamma$ ) are scarce and cover only a fraction of the neutron energy range of interest. (n;$\\gamma$ ) cross sections will be measured in the full energy range from 25 meV to about 200 keV at n TOF EAR-1.

  7. Eikonal calculation of electron-capture cross sections in collisions of H atoms with fast projectiles

    International Nuclear Information System (INIS)

    Ho, T.S.; Lieber, M.; Chan, F.T.

    1981-01-01

    We have employed the eikonal method to calculate the cross section for the capture of an electron into an arbitrary nl subshell in collisions between hydrogen atoms and fast projectiles. the projectiles were protons, C 6+ , O 8+ , and Fe 24+ . The energy ranges considered were 20--100 keV in the proton case, and 40--200 keV per nucleon in the other cases. These projectiles were selected because of their importance in fusion plasmas. For the highly charged case of Fe 24+ we found that our formulas, while exact, involved a high degree of cancellation and produced unreliable numerical results, so that a numerical integration of the penultimate formula was substituted. In the proton case agreement with recent experimental data is excellent

  8. Coupled-channel calculations of partial capture cross sections in multiply charged ion collisions with hydrogen

    International Nuclear Information System (INIS)

    Hansen, J.P.; Taulbjerg, K.; University of Tennessee, Knoxville, Tennessee 37996)

    1989-01-01

    Partial cross sections for electron capture in 1--50-keV collisions of Ar 6+ and Ar 8+ with atomic hydrogen have been calculated using an atomic expansion including two complete principal shells of final states (n=4,5 for Ar 6+ and n=5,6 for Ar 8+ ). The qualitative structure of the results is in good accord with a reaction window picture. The results for Ar 6+ ions are in agreement with published experimental data when precaution is taken with respect to uncertainties in absolute normalization of the data and with respect to a proper analysis of translation energy spectra at lower impact energies. The limited experimental data for Ar 8+ do not agree with the present results

  9. Electron capture cross sections by O{sup +} from atomic He

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, Dwayne C; Saha, Bidhan C [Department of Physics, Florida A and M University, Tallahassee, FL-32307 (United States)

    2009-11-01

    The adiabatic representation is used in both the quantal and semi classical molecular orbital close coupling methods (MOCC) to evaluate charge exchange cross sections. Our results show good agreement with experimental cross sections

  10. Theory of inelastic multiphonon scattering and carrier capture by defects in semiconductors: Application to capture cross sections

    Science.gov (United States)

    Barmparis, Georgios D.; Puzyrev, Yevgeniy S.; Zhang, X.-G.; Pantelides, Sokrates T.

    2015-12-01

    Inelastic scattering and carrier capture by defects in semiconductors are the primary causes of hot-electron-mediated degradation of power devices, which holds up their commercial development. At the same time, carrier capture is a major issue in the performance of solar cells and light-emitting diodes. A theory of nonradiative (multiphonon) inelastic scattering by defects, however, is nonexistent, while the theory for carrier capture by defects has had a long and arduous history. Here we report the construction of a comprehensive theory of inelastic scattering by defects, with carrier capture being a special case. We distinguish between capture under thermal equilibrium conditions and capture under nonequilibrium conditions, e.g., in the presence of an electrical current or hot carriers where carriers undergo scattering by defects and are described by a mean free path. In the thermal-equilibrium case, capture is mediated by a nonadiabatic perturbation Hamiltonian, originally identified by Huang and Rhys and by Kubo, which is equal to linear electron-phonon coupling to first order. In the nonequilibrium case, we demonstrate that the primary capture mechanism is within the Born-Oppenheimer approximation (adiabatic transitions), with coupling to the defect potential inducing Franck-Condon electronic transitions, followed by multiphonon dissipation of the transition energy, while the nonadiabatic terms are of secondary importance (they scale with the inverse of the mass of typical atoms in the defect complex). We report first-principles density-functional-theory calculations of the capture cross section for a prototype defect using the projector-augmented wave, which allows us to employ all-electron wave functions. We adopt a Monte Carlo scheme to sample multiphonon configurations and obtain converged results. The theory and the results represent a foundation upon which to build engineering-level models for hot-electron degradation of power devices and the performance

  11. Revisiting the U-238 thermal capture cross section and gamma-raymission probabilities from Np-239 decay

    Energy Technology Data Exchange (ETDEWEB)

    Trkov, A.; Molnar, G.L.; Revay, Zs.; Mughabghab, S.F.; Firestone,R.B.; Pronyaev, V.G.; Nichols, A.L.; Moxon, M.C.

    2005-03-03

    The precise value of the thermal capture cross section of238U is uncertain, and evaluated cross sections from various sourcesdiffer by more than their assigned uncertainties. A number of theoriginal publications have been reviewed to assess the discrepant data,corrections were made for more recent standard cross sections andotherconstants, and one new measurement was analyzed. Due to the strongcorrelations in activation measurements, the gamma-ray emissionprobabilities from the beta decay of 239Np were also analyzed. As aresult of the analysis, a value of 2.683 +- 0.012 barns was derived forthe thermal capture cross section of 238U. A new evaluation of thegamma-ray emission probabilities from 239Np decay was alsoundertaken.

  12. Sensitivity coefficients for the 238U neutron-capture shielded-group cross sections

    International Nuclear Information System (INIS)

    Munoz-Cobos, J.L.; de Saussure, G.; Perez, R.B.

    1981-01-01

    In the unresolved resonance region cross sections are represented with statistical resonance parameters. The average values of these parameters are chosen in order to fit evaluated infinitely dilute group cross sections. The sensitivity of the shielded group cross sections to the choice of mean resonance data has recently been investigated for the case of 235 U and 239 Pu by Ganesan and by Antsipov et al; similar sensitivity studies for 238 U are reported

  13. New approach to the adjustment of group cross sections fitting integral measurements

    International Nuclear Information System (INIS)

    Chao, Y.A.

    1979-01-01

    The adjustment of group cross sections fitting integral measurements is viewed as a process of estimating theoretical and/or experimental negligence errors to bring statistical consistency to the integral and differential data so that they can be combined to form an enlarged ensemble, based on which an improved estimation of the physical constants can be made. A three-step approach is suggested, and its formalism of general validity is developed. In step one, the data of negligence error are extracted from the given integral and differential data. The method of extraction is based on the concepts of prior probability and information entropy. It automatically leads to vanishing negligence error as the two sets of data are statistically consistent. The second step is to identify the sources of negligence error and adjust the data by an amount compensating for the extracted negligence discrepancy. In the last step, the two data sets, already adjusted to mutual consistency are combined as a single unified ensemble. Standard methods of statistics can then be applied to reestimate the physical constants. 1 figure

  14. New approach to the adjustment of group cross-sections fitting integral measurements

    International Nuclear Information System (INIS)

    Chao, Y.A.

    1979-01-01

    The adjustment of group cross-sections fitting integral measurements is viewed as a process of uncovering theoretical and/or experimental negligence errors to bring statistical consistency to the integral and differential data so that they can be combined to form an enlarged ensemble, on which an improved estimation of the physical constants can be based. An approach with three steps is suggested, and its formalism of general validity is developed. In step one, the data of negligence error are extracted from the given integral and differential data. The method of extraction is based on the concepts of prior probability and information entropy. It automatically leads to vanishing negligence error as the two sets of data are statistically consistent. The second step is to identify the sources of negligence error and adjust the data by an amount compensating the extracted negligence discrepancy. In the last step the two data sets, already adjusted to mutual consistency, are combined as a single unified ensemble. Standard methods of statistics can then be applied to re-estimate the physical constants. A simple example is shown as a demonstration of the method. 1 figure

  15. The 236U neutron capture cross-section measured at the n_TOF CERN facility

    Directory of Open Access Journals (Sweden)

    Mastromarco M.

    2017-01-01

    Full Text Available The 236U isotope plays an important role in nuclear systems, both for future and currently operating ones. The actual knowledge of the capture reaction of this isotope is satisfactory in the thermal region, but it is considered insufficient for Fast Reactor and ADS applications. For this reason the 236U(n, γ reaction cross-section has been measured for the first time in the whole energy region from thermal energy up to 1 MeV at the n_TOF facility with two different detection systems: an array of C6D6 detectors, employing the total energy deposited method, and a FX1 total absorption calorimeter (TAC, made of 40 BaF2 crystals. The two n_TOF data sets agree with each other within the statistical uncertainty in the Resolved Resonance Region up to 800 eV, while sizable differences (up to ≃ 20% are found relative to the current evaluated data libraries. Moreover two new resonances have been found in the n_TOF data. In the Unresolved Resonance Region up to 200 keV, the n_TOF results show a reasonable agreement with previous measurements and evaluated data.

  16. Study of the surrogate-reaction method applied to neutron-induced capture cross sections

    International Nuclear Information System (INIS)

    Boutoux, G.; Jurado, B.; Méot, V.; Roig, O.; Mathieu, L.; Aïche, M.; Barreau, G.; Capellan, N.; Companis, I.; Czajkowski, S.; Schmidt, K.-H.; Burke, J.T.; Bail, A.; Daugas, J.M.; Faul, T.; Morel, P.; Pillet, N.; Théroine, C.; Derkx, X.; Sérot, O.

    2012-01-01

    Gamma-decay probabilities of 173 Yb and 176 Lu have been measured using the surrogate reactions 174 Yb( 3 He,αγ) 173 Yb* and 174 Yb( 3 He,pγ) 176 Lu*, respectively. For the first time, the gamma-decay probabilities have been obtained with two independent experimental methods based on the use of C 6 D 6 scintillators and Germanium detectors. Our results for the radiative-capture cross sections are several times higher than the corresponding neutron-induced data. To explain these differences, we have used our gamma-decay probabilities to extract rather direct information on the spin distributions populated in the transfer reactions used. They are about two times wider and the mean values are 3 to 4 ℏ higher than the ones populated in the neutron-induced reactions. As a consequence, in the transfer reactions neutron emission to the ground and first excited states of the residual nucleus is strongly suppressed and gamma-decay is considerably enhanced.

  17. Determination of Thermal Neutron Capture Cross Sections Using Cold Neutron Beams at the Budapest PGAA-NIPS Facilities

    International Nuclear Information System (INIS)

    Belgya, T.

    2006-01-01

    A complete elemental gamma-ray library was measured with our guided thermal beam at the Budapest PGAA facility in the period of 1995-2000. Using this data library in an IAEA CRP on PGAA it was managed to re-normalize the ENSDF intensity data with the Budapest intensities. Based on this renormalization thermal neutron cross sections were deduced for several isotopes. Most of these calculations were done by Richard B. Firestone. The Budapest PGAA-NIPS facilities have been used for routine prompt gamma activation analysis with cold neutrons since the year of 2000. The advantage of the cold neutron beam is that the neutron guide has much higher neutron transmission. This resulted in a gain factor about 20 relative to our thermal guide. For the analytical works a precise comparator technique was developed that is routinely used to determine partial gamma-ray production cross sections. An additional development of our methodology was necessary to be worked out to determine thermal neutron capture cross sections based on the partial gamma-ray production cross sections. In this talk our methodology of radiative capture cross section determination will be presented, including our latest results on 129 I, 204,206,207 Pb and 209 Bi. Most of these works were done in cooperation with people from EU-JRC-IRMM, Geel, Belgium and CEA Cadarache, France. Many partial cross sections of short lived nuclei have been re-measured with our new chopper technique. The uncertainty calculations of the radiative capture cross section determination procedures will be also shown. (authors)

  18. Adjusts of control rod cross sections and its utilization in power distribution calculations for Angra-1 reactor

    International Nuclear Information System (INIS)

    Pina, C.M. de

    1981-01-01

    One of the most important part in neutronics calculations is the study of core behavior with inserted control rods. The first stage of this calculations consists in generating equivalent microscopic cross sections for the basic cells containing fuel or absorbed material. The cross sections will be then adjusted. The choice of parameters that help in those adjustments, were obtained by the comparisons of data coming from the control rod supercell calculations with the Hammer and Citation computer codes. The effect of those adjustments in core integral parameters was evaluated; in this work only the core power two-dimensional distribution calculations with the D bank completely inserted, is studied. (E.G.) [pt

  19. Measurement and analysis of the $^{243}$Am neutron capture cross section at the n_TOF facility at CERN

    CERN Document Server

    Mendoza, E; Guerrero, C; Berthoumieux, E; Abbondanno, U; Aerts, G; Alvarez-Velarde, F; Andriamonje, S; Andrzejewski, J; Assimakopoulos, P; Audouin, L; Badurek, G; Balibrea, J; Baumann, P; Becvar, F; Belloni, F; Calvino, F; Calviani, M; Capote, R; Carrapico, C; Carrillo de Albornoz, A; Cennini, P; Chepel, V; Chiaveri, E; Colonna, N; Cortes, G; Couture, A; Cox, J; Dahlfors, M; David, S; Dillmann, I; Dolfini, R; Domingo-Pardo, C; Dridi, W; Duran, I; Eleftheriadis, C; Ferrant†, L; Ferrari, A; Ferreira-Marques, R; Fitzpatrick, L; Frais-Koelbl, H; Fujii, K; Furman, W; Goncalves, I; Gonz alez-Romero, E; Goverdovski, A; Gramegna, F; Griesmayer, E; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martinez, A; Igashira, M; Isaev, S; Jericha, E; Kappeler, F; Kadi, Y; Karadimos, D; Karamanis, D; Ketlerov, V; Kerveno, M; Koehler, P; Konovalov, V; Kossionides, E; Krticka, M; Lampoudis, C; Leeb, H; Lindote, A; Lopes, I; Lossito, R; Lozano, M; Lukic, S; Marganiec, J; Marques, L; Marrone, S; Martınez, T; Massimi, C; Mastinu, P; Mengoni, A; Milazzo, P M; Moreau, C; Mosconi, M; Neves, F; Oberhummer, H; O’Brien, S; Oshima, M; Pancin, J; Papachristodoulou, C; Papadopoulos, C; Paradela, C; Patronis, N; Pavlik, A; Pavlopoulos, P; Perrot, L; Pigni, M T; Plag, R; Plompen, A; Plukis, A; Poch, A; Praena, J; Pretel, C; Quesada, J; Rauscher, T; Reifarth, R; Rosetti, M; Rubbia, C; Rudolf, G; Rullhusen, P; Salgado, J; Santos, C; Sarchiapone, L; Savvidis, I; Stephan, C; Tagliente, G; Tain, J L; Tassan-Got, L; Tavora, L; Terlizzi, R; Vannini, G; Vaz, P; Ventura, A; Villamarin, D; Vicente, M C; Vlachoudis, V; Vlastou, R; Voss, F; Walter, S; Wendler, H; Wiescher, M; Wisshak, K

    2014-01-01

    Background:The design of new nuclear reactors and transmutation devices requires to reduce the present neutron cross section uncertainties of minor actinides. Purpose: Reduce the $^{243}$Am(n,$\\gamma$) cross section uncertainty. Method: The $^{243}$Am(n,$\\gamma$) cross section has been measured at the n_TOF facility at CERN with a BaF$_{2}$ Total Absorption Calorimeter, in the energy range between 0.7 eV and 2.5 keV. Results: The $^{243}$Am(n,$\\gamma$) cross section has been successfully measured in the mentioned energy range. The resolved resonance region has been extended from 250 eV up to 400 eV. In the unresolved resonance region our results are compatible with one of the two incompatible capture data sets available below 2.5 keV. The data available in EXFOR and in the literature has been used to perform a simple analysis above 2.5 keV. Conclusions: The results of this measurement contribute to reduce the $^{243}$Am(n,$\\gamma$) cross section uncertainty and suggest that this cross section is underestimate...

  20. Status of recent fast capture cross section evaluations for important fission product nuclides

    International Nuclear Information System (INIS)

    Gruppelaar, H.

    1982-01-01

    A comparison is made between recent evaluations of fission-product cross sections as given in the CNEN/CEA, ENDF/B-IV, ENDF/V-V, JENDL-1, RCN-2 and RCN-3 data libraries. The intercomparison is restricted to 24 important fission products in a fast power reactor. The evaluation methods used to obtain the various data files are reviewed and possible shortcomings are indicated. A survey is given of the experimental data based used in the various evaluations. Some graphs are included showing the new ENDF/B-V and RCN-3 fastcapture cross-section evaluations. Further intercomparisons are made by means of multi-group and one-group cross sections. It is shown that lumped fission-product cross sections calculated from the most recent versions of the data files are in quite good agreement with each other. This review concludes with a discussion on observed discrepancies and requests for new measurements. 78 references

  1. Uncertainties of Electron Capture Cross Sections In Be4+ + H(1s) Collisions

    International Nuclear Information System (INIS)

    Méndez, L.; Illescas, Clara; Jorge, Alba; Errea, L.F.; Rabadán, I.; Suárez, J.

    2014-01-01

    We have considered one-electron systems where the theoretical methods are well established. The use of different computational alternatives enables the accurate evaluation of nl-partial cross sections in a wide range of collision energies. In the presentation we have analyzed the uncertainties of n-partial charge exchange (CX) cross sections in Be 4+ + H(1s) collisions, which are relevant in tokamak plasmas and experimental data are not available.

  2. Measurement of the effective thermal cross section of {sup 134}Cs by triple neutron capture reaction

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Shoji; Harada, Hideo; Katoh, Toshio [Power Reactor and Nuclear Fuel Development Corp., Tokai, Ibaraki (Japan). Tokai Works; Hatsukawa, Yuichi; Shinohara, Nobuo; Hata, Kentaro; Kobayashi, Katsutoshi; Motoishi, Shoji; Tanase, Masakazu

    1998-03-01

    The effective thermal cross section ({sigma}{sub eff}) of the {sup 134}Cs(n,{gamma}){sup 135}Cs reaction was measured by the activation method and the {gamma}-ray spectroscopic method in order to obtain fundamental data for research on the transmutation of nuclear wastes. The effective thermal cross section of the reaction {sup 134}Cs(n,{gamma}){sup 135}Cs was found to be 140.6{+-}8.5 barns. (author)

  3. Neutron Capture Gamma Ray Cross Sections for Ta, Ag, In and Au between 30 and 175 keV

    International Nuclear Information System (INIS)

    Hellstroem, J.; Beshai, S.

    1971-11-01

    A new detector has been used to determine neutron capture gamma ray cross sections for Ta, Ag, In and Au. The results are listed and discussed together with associated problems. The energy range from 30 keV to 175 keV is considered

  4. A compact multi-plate fission chamber for the simultaneous measurement of 233U capture and fission cross-sections

    Directory of Open Access Journals (Sweden)

    Bacak M.

    2017-01-01

    Full Text Available 233U plays the essential role of fissile nucleus in the Th-U fuel cycle. A particularity of 233U is its small neutron capture cross-section which is about one order of magnitude lower than the fission cross-section on average. Therefore, the accuracy in the measurement of the 233U capture cross-section essentially relies on efficient capture-fission discrimination thus a combined setup of fission and γ-detectors is needed. At CERN n_TOF the Total Absorption Calorimeter (TAC coupled with compact fission detectors is used. Previously used MicroMegas (MGAS detectors showed significant γ-background issues above 100 eV coming from the copper mesh. A new measurement campaign of the 233U capture cross-section and alpha ratio is planned at the CERN n_TOF facility. For this measurement, a novel cylindrical multi ionization cell chamber was developed in order to provide a compact solution for 14 active targets read out by 8 anodes. Due to the high specific activity of 233U fast timing properties are required and achieved with the use of customized electronics and the very fast ionizing gas CF4 together with a high electric field strength. This paper describes the new fission chamber and the results of the first tests with neutrons at GELINA proving that it is suitable for the 233U measurement.

  5. Neutron Capture Gamma Ray Cross Sections for Ta, Ag, In and Au between 30 and 175 keV

    Energy Technology Data Exchange (ETDEWEB)

    Hellstroem, J; Beshai, S

    1971-11-15

    A new detector has been used to determine neutron capture gamma ray cross sections for Ta, Ag, In and Au. The results are listed and discussed together with associated problems. The energy range from 30 keV to 175 keV is considered

  6. Radiochemical determination of the neutron capture cross sections of {sup 241}Am irradiated in the JMTR reactor

    Energy Technology Data Exchange (ETDEWEB)

    Shinohara, N.; Hatsukawa, Y.; Hata, K.; Kohno, N. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    The thermal neutron capture cross section {sigma}{sub 0} and Resonance integral I{sub 0} of {sup 241}Am leading to the production of {sup 242m}Am and {sup 242g}Am were measured by radiochemical method. The cross sections obtained in this study are {sigma}{sub 0}=60.9 {+-} 2.6 barn, I{sub 0}=213 {+-} 13 barn for {sup 241}Am(n,{gamma}){sup 242m}Am and {sigma}{sub 0}=736 {+-} 31 barn, I{sub 0}=1684 {+-} 92 barn for {sup 241}Am(n,{gamma}){sup 242g}Am. (author)

  7. Neutron capture cross section measurement of $^{151}Sm$ at the CERN neutron Time of Flight Facility (nTOF)

    CERN Document Server

    Abbondanno, U; Alvarez-Velarde, F; Alvarez-Pol, H; Andriamonje, Samuel A; Andrzejewski, J; Badurek, G; Baumann, P; Becvar, F; Benlliure, J; Berthoumieux, E; Calviño, F; Cano-Ott, D; Capote, R; Cennini, P; Chepel, V; Chiaveri, Enrico; Colonna, N; Cortés, G; Cortina-Gil, D; Couture, A; Cox, J; Dababneh, S; Dahlfors, M; David, S; Dolfini, R; Domingo-Pardo, C; Durán, I; Embid-Segura, M; Ferrant, L; Ferrari, A; Ferreira-Marques, R; Frais-Kölbl, H; Furman, W; Gonçalves, I; Gallino, R; Gonzalez-Romero, E; Goverdovski, A; Gramegna, F; Griesmayer, E; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martínez, A; Isaev, S; Jericha, E; Kappeler, F; Kadi, Y; Karadimos, D; Kerveno, M; Ketlerov, V; Köhler, P; Konovalov, V; Krticka, M; Lamboudis, C; Leeb, H; Lindote, A; Lopes, I; Lozano, M; Lukic, S; Marganiec, J; Marrone, S; Martinez-Val, J; Mastinu, P; Mengoni, A; Milazzo, P M; Molina-Coballes, A; Moreau, C; Mosconi, M; Neves, F; Oberhummer, Heinz; O'Brien, S; Pancin, J; Papaevangelou, T; Paradela, C; Pavlik, A; Pavlopoulos, P; Perlado, J M; Perrot, L; Pignatari, M; Plag, R; Plompen, A; Plukis, A; Poch, A; Policarpo, Armando; Pretel, C; Quesada, J; Raman, S; Rapp, W; Rauscher, T; Reifarth, R; Rosetti, M; Rubbia, Carlo; Rudolf, G; Rullhusen, P; Salgado, J; Soares, J C; Stéphan, C; Tagliente, G; Taín, J L; Tassan-Got, L; Tavora, L; Terlizzi, R; Vannini, G; Vaz, P; Ventura, A; Villamarín, D; Vincente, M C; Vlachoudis, V; Voss, F; Wendler, H; Wiescher, M; Wissha, K

    2004-01-01

    The measurement of **1**5**1Sm(n, gamma)**1**5**2Sm (samarium) cross section showed improved performance of the new spallation neutron facility. It covered a wide energy range with good resolution, high neutron flux, low backgrounds and a favourable duty factor. The samarium cross section was found to be of great importance for characterizing neutron capture nucleosynthesis in asymptotic giant stars. The combination of these features provided a promising basis for a broad experimental program directed towards application in astrophysics and advanced nuclear technologies. (Edited abstract)

  8. Cross sections for one-electron capture by highly stripped ions of Be, B and C from H2 and Ar below 10 keV

    International Nuclear Information System (INIS)

    Takagi, S.; Ohtani, S.; Kadota, K.; Fujita, J.

    1982-03-01

    Cross sections for one-electron capture by highly stripped ions of Be, B and C from H 2 and Ar are measured at low energies below 10 keV. The cross sections are nearly independent of the collision energy investigated. The distinct oscillation with incident ionic charge g in the cross sections are observed. (author)

  9. Measurement of the neutron capture cross-section of 232Th using the neutron activation technique

    International Nuclear Information System (INIS)

    Naik, H.; Singh, Sarbjit; Goswami, A.; Manchanda, V.K.; Prajapati, P.M.; Surayanarayana, S.V.; Nayak, B.K.; Sharma, S.C.; Jagadeesan, K.C.; Thakare, S.V.; Raj, D.; Ganesan, S.; Mulik, V.K.; Sivashankar, B.S.; Mukherjee, S.

    2011-01-01

    The 232 Th(n, γ) reaction cross-section at average neutron energies of 3.7±0.3 MeV and 9.85±0.38 MeV from the 7 Li(p, n) reaction has been determined for the first time using activation and off-line γ -ray spectrometric technique. The 232 Th(n, 2n) reaction cross-section at the average neutron energy of 9.85±0.38 MeV has been also determined using the same technique. The experimentally determined 232 Th(n, γ) and 232 Th(n, 2n) reaction cross-sections were compared with the evaluated data of ENDF/B-VII, JENDL-4.0 and JEFF-3.1 and were found to be in good agreement. The present data along with literature data in a wide range of neutron energies were interpreted in terms of competition between different reaction channels including fission. The 232 Th(n, γ) and 232 Th(n, 2n) reaction cross-sections were also calculated theoretically using the TALYS 1.2 computer code and were found to be slightly higher than the experimental data. (orig.)

  10. Cross Sections for High-Energy Gamma Transitions from MeV Neutron Capture in {sup 206}Pb

    Energy Technology Data Exchange (ETDEWEB)

    Bergqvist, I; Lundberg, B; Nilsson, L

    1970-03-15

    Gamma-ray spectra from neutron capture in Pb (radiogenic lead) in the energy range 1.5 to 8.5 MeV were recorded using time-of-flight techniques. The spectrometer was a Nal (Tl) crystal, 20.8 cm long and 22.6 cm in diameter. The spectra are dominated by gamma transitions to levels with large single-particle strength, in agreement with predictions of semi-direct capture theories. The theories predict enhancements of the direct capture cross section by a factor of 10 - 15 in the region of the giant dipole resonance. The observed enhancement is about 50.

  11. 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.

  12. Methodological study of the adjustment of multigroup cross sections for fast reactors, by means of integral data

    International Nuclear Information System (INIS)

    Bastos, H.F.B.N.

    1979-01-01

    In this work a study of the methodology of the adjustment of multigroup cross sections by means of integral data is presented. A synthesis of the principal methods existent and the mathematical development of the adaptation of one of them are made. A calculational system is built from this reference method, with the basic conditions for the operation of the process of adjustment. In order to test the system developed and analyze several problems related to the adjustment, a series of trial adjustments was made with the value of the U 235 fission cross section from the infinite dilution library used in the calculational system for fast reactors of the Instituto de Engenharia Nuclear. (author)

  13. Thermal neutron capture and resonance integral cross sections of {sup 45}Sc

    Energy Technology Data Exchange (ETDEWEB)

    Van Do, Nguyen; Duc Khue, Pham; Tien Thanh, Kim [Institute of Physics, Vietnam Academy of Science and Technology, 10 Dao Tan, Hanoi (Viet Nam); Thi Hien, Nguyen [Institute of Physics, Vietnam Academy of Science and Technology, 10 Dao Tan, Hanoi (Viet Nam); Department of Physics and Center for High Energy Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Kim, Guinyun, E-mail: gnkim@knu.ac.kr [Department of Physics and Center for High Energy Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Kim, Kwangsoo [Department of Physics and Center for High Energy Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Shin, Sung-Gyun; Cho, Moo-Hyun [Department of Advanced Nuclear Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Lee, Manwoo [Research Center, Dongnam Institute of Radiological and Medical Science, Busan 619-953 (Korea, Republic of)

    2015-11-01

    The thermal neutron cross section (σ{sub 0}) and resonance integral (I{sub 0}) of the {sup 45}Sc(n,γ){sup 46}Sc reaction have been measured relative to that of the {sup 197}Au(n,γ){sup 198}Au reaction by means of the activation method. High-purity natural scandium and gold foils without and with a cadmium cover of 0.5 mm thickness were irradiated with moderated pulsed neutrons produced from the Pohang Neutron Facility (PNF). The induced activities in the activated foils were measured with a high purity germanium (HPGe) detector. In order to improve the accuracy of the experimental results the counting losses caused by the thermal (G{sub th}) and resonance (G{sub epi}) neutron self-shielding, the γ-ray attenuation (F{sub g}) and the true γ-ray coincidence summing effects were made. In addition, the effect of non-ideal epithermal spectrum was also taken into account by determining the neutron spectrum shape factor (α). The thermal neutron cross-section and resonance integral of the {sup 45}Sc(n,γ){sup 46}Sc reaction have been determined relative to the reference values of the {sup 197}Au(n,γ){sup 198}Au reaction, with σ{sub o,Au} = 98.65 ± 0.09 barn and I{sub o,Au} = 1550 ± 28 barn. The present thermal neutron cross section has been determined to be σ{sub o,Sc} = 27.5 ± 0.8 barn. According to the definition of cadmium cut-off energy at 0.55 eV, the present resonance integral cross section has been determined to be I{sub o,Sc} = 12.4 ± 0.7 barn. The present results are compared with literature values and discussed.

  14. Thermal neutron capture cross section for Fe-56(n,gamma)

    Czech Academy of Sciences Publication Activity Database

    Firestone, R. B.; Belgya, T.; Krtička, M.; Bečvář, F.; Szentmiklosi, L.; Tomandl, Ivo

    2017-01-01

    Roč. 95, č. 1 (2017), č. článku 014328. ISSN 2469-9985 R&D Projects: GA ČR GA13-07117S; GA MŠk LM2015056 Institutional support: RVO:61389005 Keywords : neutron cross section * gamma gamma-coincidence data Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders OBOR OECD: Nuclear physics Impact factor: 3.820, year: 2016

  15. Thermal neutron capture cross section of chromium, vanadium, titanium and nickel isotopes

    International Nuclear Information System (INIS)

    Venturini, L.; Pecequilo, B.R.S.

    1990-04-01

    The thermal neutron cross section of chromium, vanadium, titanium and nickel can be determined by measuring the pair spectrum of prompt gamma-rays emitted targets of these elements are irradiated by a thermal neutron beam. Such measurements were carried out by irradiating the natural element mixed with a nitrogen standard (melamine) in the tangential beam hole of the IEA-R1 research reactor. The pair spectrometer efficiency calibration curve in the 1.5 to 11 MeV energy range was performed with a melamine plus ammonium chloride mixed target. The cross section was calculated for the most prominent gamma transitions of each isotope, using nitrogen as standard and averaged over the obtained values. The resulting mean cross sections are as follows: (13.4 ± 0.7)b for 50 Cr, (0.79 ± 0,02)b for 52 Cr, (18.1 ± 0,7)b for 53 Cr, (4.9 ± 0.2)b for 51 V, (8.4 ± 0.1)b for 48 Ti, (4.41 ± 0.08)b 58 Ni, (2.54 ± 0.07)b for 60 Ni, (15.2 ± 0.5)b for 62 Ni and (1.6 ± 0.1) for 64 Ni. (author) [pt

  16. Neutron capture and fission cross section of Americium-243 in the energy range from 5 to 250 keV

    International Nuclear Information System (INIS)

    Wisshak, K.; Kaeppeler, F.

    1983-04-01

    The neutron capture and subthreshold fission cross section of 243 Am was measured in the energy range from 5 to 250 keV using 197 Au and 235 U as the respective standards. Neutrons were produced via the 7 Li(p,n) and the T(p,n) reaction with the Karlsruhe 3-MV pulsed Van de Graaff accelerator. Capture events were detected by two MoxonRae detectors with graphite and bismuthgraphite converters, respectively. Fission events were registered by a NE-213 liquid scintillator with pulse-shape discriminator equipment. Flight paths as short as 50-70 mm were used to obtain optimum signal-to-background ratio. After correction for the different efficiency of the individual converter materials the capture cross section could be determined with a total uncertainty of 3-6%. The respective values for the fission cross section are 8-12%. The results are compared to predictions of recent evaluations, which in some cases are severely discrepant. (orig.)

  17. Use of integral experiments for the assessment of the 235U capture cross section within the CIELO Project

    Directory of Open Access Journals (Sweden)

    Ichou Raphaelle

    2016-01-01

    Full Text Available A new 235U capture cross-section evaluation, evaluated by ORNL and the CEA Bruyères-le-Châtel (BRC has been proposed within the CIELO project. IRSN, who participates in the CIELO project, contributes with data testing and has carried out benchmark calculations using few benchmarks, extracted from the ICSBEP database, for testing the new 235U evaluation. The benchmarks have been selected by privileging the experiments showing small experimental uncertainties and a significant sensitivity to 235U capture cross-section. The keff calculations were performed with both the MCNP 6 code and the 5.C.1 release of the MORET 5 code, using the ENDF/B-VII.1 library for all isotopes except 235U, for which both the ENDF/B-VII.1 and the new 235U evaluation was used. The benchmark selection allowed highlighting a significant effect on keff of the new 235U capture cross-section. The results of this data testing, provided as input for the evaluators, are presented here.

  18. Measurement of the 241Am neutron capture cross section at the n_TOF facility at CERN

    Directory of Open Access Journals (Sweden)

    Mendoza E.

    2017-01-01

    Full Text Available New neutron cross section measurements of minor actinides have been performed recently in order to reduce the uncertainties in the evaluated data, which is important for the design of advanced nuclear reactors and, in particular, for determining their performance in the transmutation of nuclear waste. We have measured the 241Am(n,γ cross section at the n_TOF facility between 0.2 eV and 10 keV with a BaF2 Total Absorption Calorimeter, and the analysis of the measurement has been recently concluded. Our results are in reasonable agreement below 20 eV with the ones published by C. Lampoudis et al. in 2013, who reported a 22% larger capture cross section up to 110 eV compared to experimental and evaluated data published before. Our results also indicate that the 241Am(n,γ cross section is underestimated in the present evaluated libraries between 20 eV and 2 keV by 25%, on average, and up to 35% for certain evaluations and energy ranges.

  19. Kuang's Semi-Classical Formalism for Calculating Electron Capture Cross Sections: A Space- Physics Application

    Science.gov (United States)

    Barghouty, A. F.

    2014-01-01

    Accurate estimates of electroncapture cross sections at energies relevant to the modeling of the transport, acceleration, and interaction of energetic neutral atoms (ENA) in space (approximately few MeV per nucleon) and especially for multi-electron ions must rely on detailed, but computationally expensive, quantum-mechanical description of the collision process. Kuang's semi-classical approach is an elegant and efficient way to arrive at these estimates. Motivated by ENA modeling efforts for apace applications, we shall briefly present this approach along with sample applications and report on current progress.

  20. Comparison of the potentials used for the calculation of the resonant coherent electron capture and loss cross sections

    International Nuclear Information System (INIS)

    Pauly, N.; Dubus, A.; Roesler, M.

    2003-01-01

    For incident protons with velocities around 1 a.u., electron capture and loss processes are known to play an important role. In particular, electron emission as well as electronic stopping power are strongly influenced by the charge changing processes. Several different electron capture and loss processes have been identified [Solid State Phys. 43 (1990) 229], i.e. Auger valence band processes, shell processes and resonant coherent processes. In the latter, the incident projectile undergoes a periodic excitation due to the periodic crystalline potential so that an electron can be lost or captured. In the literature, several different choices have been made for the crystalline potential. It is precisely the aim of the present work to review and compare the various potentials used in the literature and to show the influence of this choice on the resonant coherent electron capture and loss cross sections

  1. New neutron capture and total cross section measurements on 88Sr and their impact on s-process nucleosynthesis

    International Nuclear Information System (INIS)

    Koehler, P.E.; Spencer, R.R.; Guber, K.H.

    1998-01-01

    The authors have made new and improved measurements of the neutron capture and total cross sections of 88 Sr at the Oak Ridge Electron Linear Accelerator (ORELA). Improvements over previous measurements include a wider incident neutron energy range, the use of metallic rather than carbonate samples, better background subtraction, reduced sensitivity to sample-dependent backgrounds, and better pulse-height weighting functions. Because of its small cross section, the 88 Sr(n,γ) reaction is an important bottleneck during the s-process nucleosynthesis. Hence, an accurate determination of this rate is needed to better constrain the neutron exposure in s-process models and to more fully exploit the recently discovered isotopic anomalies in certain meteorites. They describe the experimental procedures, compare the results to previous data, and discuss their astrophysical impact

  2. Neutron Capture Cross Sections of Zr and La: Probing Neutron Exposure and Neutron Flux in Red Giant Stars

    CERN Document Server

    Kitis, G; Wiescher, M; Dahlfors, M; Soares, J

    2002-01-01

    We propose to measure the neutron capture cross sections of $^{139}$La, of $^{93}$Zr (t$_{1/2}$)=1.5 10$^{6}$ yr), and of all the stable Zr isotopes at n_TOF. The aim of these measurements is to improve the accuracy of existing results by at least a factor of three in order to meet the quality required for using the s-process nucleosynthesis as a diagnostic tool for neutron exposure and neutron flux during the He burning stages of stellar evolution. Combining these results with a wealth of recent information coming from high-resolution stellar spectroscopy and from the detailed analysis of presolar dust grains will shed new light on the chemical history of the universe. The investigated cross sections are also needed for technological applications, in particular since $^{93}$Zr is one of the major long-lived fission products.

  3. Electron-capture cross sections for low-energy highly charged neon and argon ions from molecular and atomic hydrogen

    International Nuclear Information System (INIS)

    Can, C.; Gray, T.J.; Varghese, S.L.; Hall, J.M.; Tunnell, L.N.

    1985-01-01

    Electron-capture cross sections for low-velocity (10 6 --10 7 cm/s) highly charged Ne/sup q/+ (2< or =q< or =7) and Ar/sup q/+ (2< or =q< or =10)= projectiles incident on molecular- and atomic-hydrogen targets have been measured. A recoil-ion source that used the collisions of fast heavy ions (1 MeV/amu) with target gas atoms was utilized to produce slow highly charged ions. Atomic hydrogen was produced by dissociating hydrogen molecules in a high-temperature oven. Measurements and analysis of the data for molecular- and atomic-hydrogen targets are discussed in detail. The measured absolute cross sections are compared with published data and predictions of theoretical models

  4. Influence of the Coulomb interaction in the final state on the cross section of single-electron capture by fast ions

    International Nuclear Information System (INIS)

    Novikov, N.V.; Teplova, Ya.A.

    2011-01-01

    It is shown that the Coulomb interaction of ions in the final state must be taken into account in the estimation of the cross section of electron capture by fast ions. The cross section of electron capture decreases considerably, and the dependence of the cross section on the collision energy becomes close to the experimental one if the interaction of charged particles after collision is taken into account. -- Highlights: → Coulomb interaction of ions in the final state must be taken into account. → This interaction leads to a considerable decrease in the cross section. → The dependence on energy close to the experimental one.

  5. Measurement of 235U fission spectrum-averaged cross sections and neutron spectrum adjusted with the activation data

    International Nuclear Information System (INIS)

    Kobayashi, Katsuhei; Kobayashi, Tooru

    1992-01-01

    The 235 U fission spectrum-averaged cross sections for 13 threshold reactions were measured with the fission plate (27 cm in diameter and 1.1 cm thick) at the heavy water thermal neutron facility of the Kyoto University Reactor. The Monte Carlo code MCNP was applied to check the deviation from the 235 U fission neutron spectrum due to the room-scattered neutrons, and it was found that the resultant spectrum was close to that of 235 U fission neutrons. Supplementally, the relations to derive the absorbed dose rates with the fission plate were also given using the calculated neutron spectra and the neutron Kerma factors. Finally, the present values of the fission spectrum-averaged cross sections were employed to adjust the 235 U fission neutron spectrum with the NEUPAC code. The adjusted spectrum showed a good agreement with the Watt-type fission neutron spectrum. (author)

  6. Electron capture to the continuum manifestation in fully differential cross sections for ion impact single ionization

    Science.gov (United States)

    Ciappina, M. F.; Fojón, O. A.; Rivarola, R. D.

    2018-04-01

    We present theoretical calculations of single ionization of He atoms by protons and multiply charged ions. The kinematical conditions are deliberately chosen in such a way that the ejected electron velocity matches the projectile impact velocity. The computed fully differential cross sections (FDCS) in the scattering plane using the continuum-distorted wave-eikonal initial state show a distinct peaked structure for a polar electron emission angle θ k = 0°. This element is absent when a first order theory is employed. Consequently, we can argue that this peak is a clear manifestation of a three-body effect, not observed before in FDCS. We discuss a possible interpretation of this new feature.

  7. New approach to the adjustment of group cross sections fitting integral measurements - 2

    International Nuclear Information System (INIS)

    Chao, Y.A.

    1980-01-01

    The method developed in the first paper concerning group cross sections fitting integral measurements is generalized to cover the case when the source of the extracted negligence discrepancy cannot be identified and the theoretical relation between the integral and differential measurements is also subject to uncertainty. The question of how to divide in such a case the negligence discrepancy between the integral and differential data is resolved. Application to a specific problem with real experimental data is shown as a demonstration of the method. 4 refs

  8. Measurement of the 232Th capture cross section in the energy region 5 keV-150 keV

    International Nuclear Information System (INIS)

    Lobo, G.; Schillebeeckx, P.; Brusegan, A.; Borella, A.; Corvi, F.; Janeva, N.; Volev, K.

    2003-01-01

    The 232 Th(n,γ) neutron capture cross-section is of great importance for accelerator driven reactor (ADS) systems based on the Thorium-Uranium fuel cycle. An analysis of the required nuclear data, reveals that the status of the 232 Th capture data is far from the requested 2 % uncertainty level. Recently 232 Th average capture measurements, between 5-200 keV neutron energy, were performed at the FzK Karlsruhe (DE). A comparison of the measured averaged capture cross section with the evaluated data files shows a reasonable agreement in the neutron energy range above 15 keV. However, discrepancies of up to 40 % at lower neutron energies are observed. The same order of discrepancies is observed when comparing their results with the results obtained by Macklin et al. at ORELA. To clarify these discrepancies we measured at IRMM the average capture cross-section at the GEel LINear Accelerator (GELINA). The measurements were performed at a 14.37 m flight-path using the Time-Of-Flight (TOF) method. The gamma rays, originating from the 232 Th(n,γ) reaction, were detected by a pair of C 6 D 6 -based liquid scintillators applying a pulse-height weighting method. The neutron flux was measured with an ionisation chamber placed at 80 cm before the Thorium sample. This chamber has a cathode loaded with two back-to-back layers of about 40 μg/cm 2 10 B. The sample consisted of a metallic natural thorium disc of 8 cm diameter and 0.5 mm thick, corresponding to a thickness of 1.588 10 -3 at/b. The background for the capture measurements consists of a time independent and time dependent component. The former, mainly produced by the radioactive decay of the sample, was deduced from measurements with a closed beam. The latter was measured by replacing the thorium sample with a 0.5 mm thick 208 Pb sample of the same size. Such a Pb sample has practically the same scattering probability as the thorium sample and has a negligible capture yield. Therefore, the 208 Pb run provides a good

  9. Mean cross sections of fast neutrons radiative capture, transmission and mean resonance parameters for the tin isotopes

    International Nuclear Information System (INIS)

    Timokhov, V.M.; Bokhovko, M.V.; Kazakov, L.E.; Kononov, V.N.; Manturov, G.N.; Poletaev, E.D.

    1988-01-01

    Results of measurements of neutron radiative capture cross sections in the energy range of 20-450 keV and of neutron transmission in the energy range of 20-1400 keV for 112,114,115,116,117,118,119,120,122 ,124S n isotopes and natural mixture of tin are presented. Analysis of the experimental data in the framework of nuclear reactions statistical theory is carried out, as a result of which data on neutron and radiation strength functions, potential scattering radii for S- and P-neutrons, as well as nuclear levels density parameters, are obtained

  10. Fast Neutron Radiative Capture Cross Sections for some Important Standards from 30 keV to 1.5 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Hellstroem, J

    1971-12-15

    Neutron capture radiative cross sections for Ta, Ag, In and Au have been measured between 30 keV and 1.5 MeV using time-of-flight technique. The detector used was a large liquid scintillator. Cross sections are given in relative and absolute units

  11. Fast Neutron Radiative Capture Cross Sections for some Important Standards from 30 keV to 1.5 MeV

    International Nuclear Information System (INIS)

    Hellstroem, J.

    1971-12-01

    Neutron capture radiative cross sections for Ta, Ag, In and Au have been measured between 30 keV and 1.5 MeV using time-of-flight technique. The detector used was a large liquid scintillator. Cross sections are given in relative and absolute units

  12. Importance of nuclear triaxiality for electromagnetic strength, level density and neutron capture cross sections in heavy nuclei

    CERN Document Server

    Grosse, Eckart; Massarczyk, Ralph

    2014-01-01

    Cross sections for neutron capture in the range of unresolved resonances are predicted simultaneously to level distances at the neutron threshold for more than 100 spin-0 target nuclei with A >70. Assuming triaxiality in nearly all these nuclei a combined parameterization for both, level density and photon strength is presented. The strength functions used are based on a global fit to IVGDR shapes by the sum of three Lorentzians adding up to the TRK sum rule and theory-based predictions for the A-dependence of pole energies and spreading widths. For the small spins reached by capture level densities are well described by only one free global parameter; a significant collective enhancement due to the deviation from axial symmetry is observed. Reliable predictions for compound nuclear reactions also outside the valley of stability as expected from the derived global parameterization are important for nuclear astrophysics and for the transmutation of nuclear waste.

  13. Fast-neutron capture cross sections for the most important fission-product nuclei

    International Nuclear Information System (INIS)

    Gruppelaar, H.

    1982-01-01

    The main activity of the fission-product (FP) Working Group was the discussion of the current status of neutron capture knowledge of the most important FP nuclides, including the formulation of recommendations toward improved understanding. The results of the discussion are summarized. General conclusions and recommendations are given. The status of integral data is summarized by R. Anderl; and nuclear models and calculations are reviewed by D. Gardner and G. Reffo

  14. Neutron capture cross-section of fission products in the European activation file EAF-3

    International Nuclear Information System (INIS)

    Kopecky, J.; Delfini, M.G.; Kamp, H.A.J. van der; Gruppelaar, H.; Nierop, D.

    1992-05-01

    This paper contains a description of the work performed to extend and revise the neutron capture data in the European Activation File (EAF-3) with emphasis on nuclides in the fission-product mass range. The starter was the EAF-1 data file from 1989. The present version, EAF/NG-3, contains (n,γ) excitation functions for all nuclides (729 targets) with half-lives exceeding 1/2 day in the mass range from H-1 to Cm-248. The data file is equipped with a preliminary uncertainty file, that will be improved in the near future. (author). 19 refs.; 5 figs.; 3 tabs

  15. THE WEAK s-PROCESS IN MASSIVE STARS AND ITS DEPENDENCE ON THE NEUTRON CAPTURE CROSS SECTIONS

    International Nuclear Information System (INIS)

    Pignatari, M.; Herwig, F.; Gallino, R.; Bisterzo, S.; Heil, M.; Wiescher, M.; Kaeppeler, F.

    2010-01-01

    The slow neutron capture process in massive stars (weak s process) produces most of the s-process isotopes between iron and strontium. Neutrons are provided by the 22 Ne(α,n) 25 Mg reaction, which is activated at the end of the convective He-burning core and in the subsequent convective C-burning shell. The s-process-rich material in the supernova ejecta carries the signature of these two phases. In the past years, new measurements of neutron capture cross sections of isotopes beyond iron significantly changed the predicted weak s-process distribution. The reason is that the variation of the Maxwellian-averaged cross sections (MACS) is propagated to heavier isotopes along the s path. In the light of these results, we present updated nucleosynthesis calculations for a 25 M sun star of Population I (solar metallicity) in convective He-burning core and convective C-burning shell conditions. In comparison with previous simulations based on the Bao et al. compilation, the new measurement of neutron capture cross sections leads to an increase of s-process yields from nickel up to selenium. The variation of the cross section of one isotope along the s-process path is propagated to heavier isotopes, where the propagation efficiency is higher for low cross sections. New 74 Ge, 75 As, and 78 Se MACS result in a higher production of germanium, arsenic, and selenium, thereby reducing the s-process yields of heavier elements by propagation. Results are reported for the He core and for the C shell. In shell C-burning, the s-process nucleosynthesis is more uncertain than in the He core, due to higher MACS uncertainties at higher temperatures. We also analyze the impact of using the new lower solar abundances for CNO isotopes on the s-process predictions, where CNO is the source of 22 Ne, and we show that beyond Zn this is affecting the s-process yields more than nuclear or stellar model uncertainties considered in this paper. In particular, using the new updated initial

  16. Neutron capture cross section measurements and theoretical calculation for the {sup 186}W(n,γ){sup 187}W reaction

    Energy Technology Data Exchange (ETDEWEB)

    Al-abyad, Mogahed; Mohamed, Gehan Y. [Atomic Energy Authority, Cairo (Egypt). Experimental Nuclear Physics Dept.

    2017-08-01

    Neutron capture cross section (σ{sub 0}) and resonance integral (I{sub 0}) of the reaction {sup 186}W(n,γ){sup 187}W were measured experimentally using the research reactor (ETRR-2) and an Am-Be neutron source, also calculated using TALYS-1.6 code. The present results of σ{sub 0} are (39.08±2.6, 38.75±0.98 and 38.33 barn) and I{sub 0} are (418.5±74, 439.3±36 and 445.5 barn) by using the reactor, neutron source and TALYS-1.6, respectively. The present results are in acceptable agreement with most of the previous experimental and evaluated data as well as the theoretical calculations.

  17. Measurements of thermal fission and capture cross sections of minor actinides within the Mini-INCA project

    Energy Technology Data Exchange (ETDEWEB)

    Bringer, O.; Chabod, S.; Dupont, E.; Letourneau, A.; Panebianco, S.; Veyssiere, Ch. [CEA Saclay, Dept. d' Astrophysique de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee, 91- Gif sur Yvette (France); Oriol, L. [CEA Cadarache, Dept. d' Etudes des Reacteurs, 13 - Saint Paul lez Durance (France); Chartier, F. [CEA Saclay, Dept. de Physico-Chimie, 91 - Gif sur Yvette (France); Mutti, P. [Institut Laue Langevin, 38 - Grenoble, (France); AlMahamid, I. [Wadsworth Center, New York State Dept. of Health, Albany, NY (United States)

    2008-07-01

    In the framework of nuclear waste transmutation studies, the Mini-INCA project has been initiated at Cea/DSM to determine optimal conditions for transmutation and incineration of Minor Actinides in high intensity neutron fluxes in the thermal region. Our experimental tool is based on alpha- and gamma-spectroscopy of irradiated samples and microscopic fission-chambers. It can provide both microscopic information on nuclear reactions (total and partial cross sections for neutron capture and/or fission reactions) and macroscopic information on transmutation and incineration potentials. The {sup 232}Th, {sup 237}Np, {sup 241}Am, and {sup 244}Cm transmutation chains have been explored in details, showing some discrepancies in comparison with evaluated data libraries but in overall good agreement with recent experimental data. (authors)

  18. Measurements of thermal fission and capture cross sections of minor actinides within the Mini-INCA project

    International Nuclear Information System (INIS)

    Bringer, O.; Chabod, S.; Dupont, E.; Letourneau, A.; Panebianco, S.; Veyssiere, Ch.; Oriol, L.; Chartier, F.; Mutti, P.; AlMahamid, I.

    2008-01-01

    In the framework of nuclear waste transmutation studies, the Mini-INCA project has been initiated at Cea/DSM to determine optimal conditions for transmutation and incineration of Minor Actinides in high intensity neutron fluxes in the thermal region. Our experimental tool is based on alpha- and gamma-spectroscopy of irradiated samples and microscopic fission-chambers. It can provide both microscopic information on nuclear reactions (total and partial cross sections for neutron capture and/or fission reactions) and macroscopic information on transmutation and incineration potentials. The 232 Th, 237 Np, 241 Am, and 244 Cm transmutation chains have been explored in details, showing some discrepancies in comparison with evaluated data libraries but in overall good agreement with recent experimental data. (authors)

  19. Is antipsychotic polypharmacy associated with metabolic syndrome even after adjustment for lifestyle effects?: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Okumura Yasuyuki

    2011-07-01

    Full Text Available Abstract Background Although the validity and safety of antipsychotic polypharmacy remains unclear, it is commonplace in the treatment of schizophrenia. This study aimed to investigate the degree that antipsychotic polypharmacy contributed to metabolic syndrome in outpatients with schizophrenia, after adjustment for the effects of lifestyle. Methods A cross-sectional survey was carried out between April 2007 and October 2007 at Yamanashi Prefectural KITA hospital in Japan. 334 patients consented to this cross-sectional study. We measured the components consisting metabolic syndrome, and interviewed the participants about their lifestyle. We classified metabolic syndrome into four groups according to the severity of metabolic disturbance: the metabolic syndrome; the pre-metabolic syndrome; the visceral fat obesity; and the normal group. We used multinomial logistic regression models to assess the association of metabolic syndrome with antipsychotic polypharmacy, adjusting for lifestyle. Results Seventy-four (22.2% patients were in the metabolic syndrome group, 61 (18.3% patients were in the pre-metabolic syndrome group, and 41 (12.3% patients were in visceral fat obesity group. Antipsychotic polypharmacy was present in 167 (50.0% patients. In multinomial logistic regression analyses, antipsychotic polypharmacy was significantly associated with the pre-metabolic syndrome group (adjusted odds ratio [AOR], 2.348; 95% confidence interval [CI], 1.181-4.668, but not with the metabolic syndrome group (AOR, 1.269; 95%CI, 0.679-2.371. Conclusions These results suggest that antipsychotic polypharmacy, compared with monotherapy, may be independently associated with an increased risk of having pre-metabolic syndrome, even after adjusting for patients' lifestyle characteristics. As metabolic syndrome is associated with an increased risk of cardiovascular mortality, further studies are needed to clarify the validity and safety of antipsychotic polypharmacy.

  20. Interim report on research between Oak Ridge National Laboratory and Japan Nuclear Cycle Development Institute on neutron-capture cross sections by long-lived fission product nuclides

    International Nuclear Information System (INIS)

    Furutaka, Kazuyoshi; Nakamura, Shoji; Harada, Hideo

    2004-03-01

    Neutron capture cross sections of long-lived fission products (LLFP) are important quantities as fundamental data for the study of nuclear transmutation of radioactive wastes. Previously obtained thermal-neutron capture gamma-ray data were analyzed to deduce the partial neutron-capture cross sections of LLFPs including 99 Tc, 93 Zr, and 107 Pd for thermal neutrons. By comparing the decay gamma-ray data and prompt gamma-ray data for 99 Tc, the relation between the neutron-capture cross section deduced by the two different methods was studied. For the isotopes 93 Zr and 107 Pd, thermal neutron-capture gamma-ray production cross sections were deduced for the first time. The level schemes of 99 Tc, 93 Zr, and 107 Pd have also been constructed form the analyzed data and compared with previously reported levels. This work has been done under the cooperative program 'Neutron Capture Cross Sections of Long-Lived Fission products (LLFPs)' by Japan Nuclear Cycle Development Institute (JNC) and Oak Ridge National Laboratory (ORNL). (author)

  1. Neutron capture cross section measurements: case of lutetium isotopes; Mesures de donnees de sections efficaces de capture radiative de neutrons: application au cas du lutecium

    Energy Technology Data Exchange (ETDEWEB)

    Roig, O.; Meot, V.; Belier, G. [CEA Bruyeres-le-Chatel, 91 (France)

    2011-07-15

    The neutron radiative capture is a nuclear reaction that occurs in the presence of neutrons on all isotopes and on a wide energy range. The neutron capture range on Lutetium isotopes, presented here, illustrates the variety of measurements leading to the determination of cross sections. These measurements provide valuable fundamental data needed for the stockpile stewardship program, as well as for nuclear astrophysics and nuclear structure. Measurements, made in France or in United-States, involving complex detectors associated with very rare targets have significantly improved the international databases and validated models of nuclear reactions. We present results concerning the measurement of neutron radiative capture on Lu{sup 173}, Lu{sup 175}, Lu{sup 176} and Lu{sup 177m}, the measurement of the probability of gamma emission in the substitution reaction Yb{sup 174}(He{sup 3},p{gamma})Lu{sup 176}. The measurement of neutron cross sections on Lu{sup 177m} have permitted to highlight the process of super-elastic scattering

  2. Measurements of 14 MeV neutron radiative capture γ-ray spectra and integrated cross sections in Sc, Y, Pr and Ho

    International Nuclear Information System (INIS)

    Budnar, M.; Cvelbar, F.; Likar, A.; Martincic, R.; Potokar, M.; Ivkovic, V.

    1977-01-01

    Gamma ray spectra and integrated cross sections for radiative capture in 45 Sc, 89 Y, 141 Pr and 165 Ho have been measured. Obtained integrated cross sections (800+-110)μb, (1490+-210)μb, (980+-160)μb and (940+-150)μb are in accordance with measurements at other elements showing smooth mass dependence. Measuring procedure and experimental data evaluation is described in details. (author)

  3. Double electron capture cross-sections of the ground state in the collisions of He2+ and Li3+ with He

    International Nuclear Information System (INIS)

    Purkait, M.

    2004-01-01

    We investigate the problem of the double charge transfer cross-section of a helium atom by bare ions of helium and lithium at energies ranging from 60 to 200 keV/amu. The boundary corrected continuum intermediate state approximation (BCCIS) is used to calculate the capture cross-section in the ground state. The continuum state of each electron has been accounted for in the formalism. The present results are compared with existing theoretical and experimental results. (authors)

  4. Measurement of the 232Th neutron capture cross section in the region 5 keV-150 keV

    International Nuclear Information System (INIS)

    Lobo, Georges; Corvi, Franco; Schillebeeckx, Peter; Brusegan, Antonio; Mutti, Paolo; Janeva, Natalia

    2002-01-01

    The average capture cross-section of 232 Th has been measured at the 14.37 m flight path of GELINA, IRMM-Geel, in the energy range from 5 to 150 keV. The capture events were detected by two C 6 D 6 liquid scintillators and the neutron flux was measured with a 10 B-loaded ionisation chamber. The data, corrected with the pulse-height weighting technique, have been normalised to the well-isolated and nearly saturated 232 Th (n, γ) resonances at 21.8 eV and 23.5 eV. Below 15 keV neutron energy, we do not observe the discrepancies, up to 40%, with the evaluated ENDF/B-VI data as reported by Wisshak et al.. Between 5 and 80 keV our results are about 10% systematically above the ENDF/B-VI data and approach the evaluated data between 80 and 100 keV. (author)

  5. Application of an iterative methodology for cross-section and variance/covariance data adjustment to the analysis of fast spectrum systems accounting for non-linearity

    International Nuclear Information System (INIS)

    Pelloni, Sandro

    2014-01-01

    Highlights: • Our data adjustment is based on a Generalized Linear Least-Squares approach. • The computed sensitivity coefficients are converged within an iterative procedure. • The corresponding multistep adjustment thus accounts for non-linearity. • It provides a more accurate simulation of fast-spectrum experiments. - Abstract: The data assimilation benchmark launched by the “Subgroup 33” on “Methods and issues for the combined use of integral experiments and covariance data” of the Working Party on Evaluation Cooperation (WPEC) of the OECD Nuclear Energy Agency Nuclear Science Committee is recalculated by means of a multistep adjustment procedure using the deterministic code system ERANOS in conjunction with a dedicated Generalized Linear Least-Squares approach based on the Bayesian parameter estimation method. Nuclear data in terms of multi-group cross-sections as well as their variances and covariances, are adjusted for 11 nuclides, namely 10 B, 16 O, 23 Na, 56 Fe, 52 Cr, 58 Ni, 235 U, 238 U, 239 Pu, 240 Pu and 241 Pu and 6 nuclear reactions which are elastic and inelastic scattering, lumped (n,2n) and (n,3n), capture, fission and ν ¯ . The adjustment is carried out by making use of experimental data for 19 integral parameters obtained in 7 different fast spectrum systems. In the determination of a posteriori values for these integral parameters including effective multiplication factors, spectral indices and void effects, along with their nuclear data uncertainty, the required adjusted data for these nuclides and reactions are generated in conjunction with pre-computed sensitivity coefficients of the analytical integral parameters to the nuclear data to adjust. The suggested multistep scheme aims at accounting for non-linear effects. Correspondingly, the sensitivity coefficients are recalculated within an iterative procedure on the basis of the a posteriori analytical values and adjusted cross-sections. The adjustment is thus repeated

  6. Development of the adjusted nuclear cross-section library based on JENDL-3.2 for large FBR

    International Nuclear Information System (INIS)

    Yokoyama, Kenji; Ishikawa, Makoto; Numata, Kazuyuki

    1999-04-01

    JNC (and PNC) had developed the adjusted nuclear cross-section library in which the results of the JUPITER experiments were reflected. Using this adjusted library, the distinct improvement of the accuracy in nuclear design of FBR cores had been achieved. As a recent research, JNC develops a database of other integral data in addition to the JUPITER experiments, aiming at further improvement for accuracy and reliability. In 1991, the adjusted library based on JENDL-2, JFS-3-J2 (ADJ91R), was developed, and it has been used on the design research for FBR. As an evaluated nuclear library, however, JENDL-3.2 is recently used. Therefore, the authors developed an adjusted library based on JENDL-3.2 which is called JFS-3-J3.2(ADJ98). It is known that the adjusted library based on JENDL-2 overestimated the sodium void reactivity worth by 10-20%. It is expected that the adjusted library based on JENDL-3.2 solve the problem. The adjusted library JFS-3-J3.2(ADJ98) was produced with the same method as the adjusted library JFS-3-J2(ADJ91R) and used more integral parameters of JUPITER experiments than the adjusted library JFS-3-J2(ADJ91R). This report also describes the design accuracy estimation on a 600 MWe class FBR with the adjusted library JFS-3-J3.2(ADJ98). Its main nuclear design parameters (multiplication factor, burn-up reactivity loss, breeding ratio, etc.) except the sodium void reactivity worth which are calculated with the adjusted library JFS-3-J3.2(ADJ98) are almost the same as those predicted with JFS-3-J2(ADJ91R). As for the sodium void reactivity, the adjusted library JFS-3-J3.2(ADJ98) estimates about 4% smaller than the JFS-3-J2(ADJ91R) because of the change of the basic nuclear library from JENDL-2 to JENDL-3.2. (author)

  7. Neutron capture cross section measurements of $^{238}$U, $^{241}$Am and $^{243}$Am at n_TOF

    CERN Multimedia

    Koehler, P E; Plag, R

    The increase of the world energy demand and the need of low carbon energy sources have triggered the renaissance and/or enhancement of nuclear energy in many countries. Fundamental nuclear physics can contribute in a practical way to the sustainability and safety of the nuclear energy production and the management of the nuclear waste. There exists a series of recent studies which address the most relevant isotopes, decay data, nuclear reaction channels and energy ranges which have to be investigated in more detail for improving the design of different advanced nuclear systems [1] and nuclear fuel cycles [2]. In this proposal, we aim at the measurement of the neutron capture cross sections of $^{238}$U, $^{241}$Am and $^{243}$Am. All three isotopes are listed in the NEA High Priority Request List [37], are recommended for measurements [1] and play an important role in the nuclear energy production and fuel cycle scenarios. The measurements will provide as well valuable nuclear structure data necessary for the...

  8. The Gogny-HFB+QRPA dipole strength function and its application to radiative neutron capture cross section

    Directory of Open Access Journals (Sweden)

    Goriely Stephane

    2018-01-01

    Full Text Available Valuable theoretical predictions of nuclear dipole excitations in the whole chart are of great interest for different nuclear applications, including in particular nuclear astrophysics. Here we extend our large-scale calculations of the E1 and M1 absorption γ-ray strength function obtained in the framework of the axially-symmetric deformed quasiparticle random phase approximation (QRPA based on the finite-range D1M Gogny force to the determination of the de-excitation strength function. To do so, shell-model calculations of the de-excitation dipole strength function as well as experimental data are considered to provide insight in the low-energy limit and to complement the QRPA estimate phenomenologically. We compare our final prediction of the E1 and M1 strengths with available experimental data at low energies and show that a relatively good agreement can be obtained. Its impact on the average radiative width as well as radiative neutron capture cross section is discussed.

  9. Evaluation of sodium-23 neutron capture cross section data for the ENDF/B V-III file

    International Nuclear Information System (INIS)

    Paik, N.C.; Pitterle, T.A.

    1975-01-01

    The evaluation of neutron cross sections of 23 Na, material number 1156, for the ENDF/B File is described. Cross sections were evaluated between 10 -5 eV and 15 MeV. Experimental data available up to March 1971 were included in the evaluation

  10. Neutron capture cross sections of rhodium, thulium, iridium, and gold between 0.5 and 3.0 MeV

    International Nuclear Information System (INIS)

    Joly, S.; Voignier, J.; Grenier, G.; Drake, D.M.; Nilsson, L.

    1979-01-01

    Measurements of the neutron capture cross sections of rhodium, thulium, gold, and iridium were carried out in the 0.5- to 3.0-MeV energy range. The cross sections are deduced from the capture gamma-ray spectra recorded by a NaI spectrometer consisting of central and annulus detectors. Time-of-flight techniques are used to improve the signal-to-background ratio. When comparison is possible, the present results are found to be in general agreement with the previous data. 5 figures, 3 tables

  11. Neutron radiative capture cross section of 232Th in the energy range 0.1 to 1.2 MeV

    International Nuclear Information System (INIS)

    Jain, H.M.; Kailas, S.

    1987-01-01

    Recently reported neutron radiative capture cross section of 232 Th measurements in the energy range 0.1 to 1.2 MeV are compared with the calculations based on the statistical model Hauser-Feshbach theory using the spherical optical model transmission coefficients and simple Fermi gas level density formula. The calculations are in good agreement with the recent experimental data, reproducing both the absolute magnitude and the shape exhibited by the excitation function. The results of this comparative study can be used for improving the evaluation of the neutron radiative capture cross section of 232 Th. 16 refs., 3 tables, 4 figures. (author)

  12. Neutron radiative capture cross section of 232Th in the energy range 0.1 to 1.2 MeV

    International Nuclear Information System (INIS)

    Jain, H.M.; Kailas, S.

    1987-03-01

    Recently reported neutron radiative capture cross section of Th-232 measurements in the energy range 0.1 to 1.2 MeV are compared with the calculations based on the statistical model Hauser-Feshbach theory using the spherical optical model transmission coefficients and simple Fermi gas level density formula. The calculations are in good agreement with the recent experimental data, reproducing both the absolute magnitude and the shape exhibited by the excitation function. The results of this comparative study can be used for improving the evaluation of the neutron radiative capture cross section of Th-232. (author)

  13. Neutron capture cross section measurements of 109Ag, 186W and 158Gd on filtered neutron beams of 55 and 144 keV

    International Nuclear Information System (INIS)

    Vuong Huu Tan; Nguyen Canh Hai; Pham Ngoc Son; Tran Tuan Anh

    2004-12-01

    The neutron capture cross sections of the 109 Ag(n, γ) 110 mAg, 186 W(n, γ) 187 W and 158 Gd(n, γ) 159 Gd have been measured at 55 and 144 keV by the activation method with filtered neutron beams of the Dalat nuclear research reactor. The cross sections were determined relative to the standard capture cross sections of 197 Au using highly purity metallic foils of Ag, W, Gd and Au. The high efficient HPGe detector was used for the gamma rays measurement from the samples, and absolute efficiency calibration was performed by using a set of standard radioisotope sources and a multi-nuclides standard solution. The present results were compared with the previous measurements listed in EXFOR-CINDA, and the evaluated data of ENDF/B-VI. (author)

  14. Resourcefulness, positive cognitions, relocation controllability and relocation adjustment among older people: a cross-sectional study of cultural differences.

    Science.gov (United States)

    Bekhet, Abir K; Zauszniewski, Jaclene A

    2013-09-01

    The population of older people in both the United States and Egypt is expected to double by the year 2030. With ageing, chronic illnesses increase and many older people need to relocate to retirement communities. Research has shown that positive cognitions and resourcefulness are positively correlated with adaptive functioning and better adjustment. The purpose of this study was to examine and compare relocation controllability, positive cognitions, resourcefulness and relocation adjustment between American and Egyptian older people living in retirement communities. The purpose of this cultural comparison is to gain insight into influencing factors in each culture that might lead to interventions to help relocated older adults in both cultures adjust to their new surroundings. A cross-sectional, descriptive design was used to compare relocation controllability, positive cognitions, resourcefulness and relocation adjustment of a convenience sample of American older people (n = 104) and a convenience sample of Egyptian older people (n = 94). The study was a secondary analysis of two studies of older people residing in six retirement communities in Northeast Ohio and in five retirement communities in Alexandria, Egypt. Examination of mean scores and standard deviations on the measure of positive cognitions using independent sample t-tests indicated that on average, the American older people reported more positive cognitions (t (131.16) = 11.29, P difference between Egyptians and Americans in resourcefulness (t (174.16) = -0.97, P > 0.05). The results provide direction for the development of positive cognition interventions and engaging older people in the decision-making process to help them to adjust to relocation. Implications for practice.  Positive thinking and resourcefulness training interventions can be used by nurses to help relocated older people to adjust to the stress of relocation to retirement communities. These interventions can be used on primary

  15. Experimental determination of neutron capture cross sections of fast reactor structure materials integrated in intermediate energy spectra. Vol. 2: description of experimental structure

    International Nuclear Information System (INIS)

    Tassan, S.

    1978-01-01

    A selection of technical documents is given concerning the experimental determination of the neutron capture cross-sections of fast reactor structural materials (Fe, Cr, Ni...) integrated over the intermediate energy spectra. The experimental structure project and modifications of the reactor RB2 for this experiment, together with criticality and safety calculations, are presented

  16. Q-Dependence of the double capture cross sections measured by electron spectroscopy at 10 qkeV (q = 4-8). Comparison with other experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Bordenave-Montesquieu, A.; Boudjema, M.; Benoit-Cattin, P.; Gleizes, A.; Moretto-Capelle, P.

    1989-01-01

    The q dependence of cross sections for double capture into autoionising states has been investigated by electron spectroscopy. It is shown that they are independent of the ionic core. Our results are compared with all other available experimental data obtained at 10 qkeV collision energy.

  17. Q-Dependence of the double capture cross sections measured by electron spectroscopy at 10 qkeV (q = 4-8). Comparison with other experimental data

    International Nuclear Information System (INIS)

    Bordenave-Montesquieu, A.; Boudjema, M.; Benoit-Cattin, P.; Gleizes, A.; Moretto-Capelle, P.

    1989-01-01

    The q dependence of cross sections for double capture into autoionising states has been investigated by electron spectroscopy. It is shown that they are independent of the ionic core. Our results are compared with all other available experimental data obtained at 10 qkeV collision energy

  18. Measurements of neutron-induced capture and fission reactions on $^{235}$ U: cross sections and ${\\alpha}$ ratios, photon strength functions and prompt ${\\gamma}$-ray from fission

    CERN Multimedia

    We propose to measure the neutron-induced capture cross section of the fissile isotope $^{235}$U using a fission tagging set-up. This new set-up has been tested successfully in 2010 and combines the n_TOF 4${\\pi}$ Total Absorption Calorimeter (TAC) with MicroMegas (MGAS) fission detectors. It has been proven that such a combination of detectors allows distinguishing with very good reliability the electromagnetic cascades from the capture reactions from dominant ${\\gamma}$-ray background coming from the fission reactions. The accurate discrimination of the fission background is the main challenge in the neutron capture cross section measurements of fissile isotopes. The main results from the measurement will be the associated capture cross section and ${\\alpha}$ ratio in the resolved (0.3-2250 eV) and unresolved (2.25-30 keV) resonance regions. According to the international benchmarks and as it is mentioned in the NEA High Priority Request List (HPRL), the 235U(n,${\\gamma}$) cross section is of utmost impo...

  19. Measurement of the 241Am and the 243Am Neutron Capture Cross Sections at the n_TOF Facility at CERN

    CERN Document Server

    Mendoza, E; Guerrero, C; Altstadt, S; Andrzejewski, J; Audouin, L; Barbagallo, M; Bécares, V; Bečvář, F; Belloni, F; Berthoumieux, E; Billowes, J; Boccone, V; Bosnar, D; Brugger, M; Calviani, M; Calviño, F; Carrapiço, C; Cerutti, F; Chiaveri, E; Chin, M; Colonna, N; Cortés, G; Cortés-Giraldo, M A; Diakaki, M; Domingo-Pardo, C; Duran, I; Dressler, R; Dzysiuk, N; Eleftheriadis, C; Ferrari, A; Fraval, K; Ganesan, S; García, A R; Giubrone, G; Gómez-Hornillos, M B; Gonçalves, I F; González-Romero, E; Griesmayer, E; Gunsing, F; Gurusamy, P; Jenkins, D G; Jericha, E; Kadi, Y; Käppeler, F; Karadimos, D; Kivel, N; Koehler, P; Kokkoris, M; Korschinek, G; Krtička, M; Kroll, J; Langer, C; Lederer, C; Leeb, H; Leong, L S; Losito, R; Manousos, A; Marganiec, J; Martínez, T; Mastinu, P F; Mastromarco, M; Massimi, C; Meaze, M; Mengoni, A; Milazzo, P M; Mingrone, F; Mirea, M; Mondelaers, W; Paradela, C; Pavlik, A; Perkowski, J; Pignatari, M; Plompen, A; Praena, J; Quesada, J M; Rauscher, T; Reifarth, R; Riego, A; Roman, F; Rubbia, C; Sarmento, R; Schillebeeckx, P; Schmidt, S; Schumann, D; Tagliente, G; Tain, J L; Tarrío, D; Tassan-Got, L; Tsinganis, A; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Versaci, R; Vermeulen, M J; Vlachoudis, V; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiß, C; Wright, T J; Žugec, P

    2014-01-01

    The capture cross sections of Am-241 and Am-243 were measured at the n\\_TOF facility at CERN in the epithermal energy range with a BaF2 Total Absorption Calorimeter. A preliminary analysis of the Am-241 and a complete analysis of the Am-243 measurement, including the data reduction and the resonance analysis, have been performed.

  20. SB2. Experiment on secondary gamma-ray production cross sections arising from thermal-neutron capture in each of 14 different elements plus a stainless steel

    International Nuclear Information System (INIS)

    Maerker, R.E.

    1976-01-01

    The experimental and calculational details for a CSEWG integral data testing shielding experiment are presented. This particular experiment measured the secondary gamma-ray production cross sections arising from thermal-neutron capture in iron, nitrogen, sodium, aluminum, copper, titanium, calcium, potassium, chlorine, silicon, ickel, zinc, barium, sulfur and a type 321 stainless steel. 1 figure, 30 tables

  1. Gamma-Ray Emission Spectra as a Constraint on Calculations of 234,236,238U Neutron-Capture Cross Sections

    Energy Technology Data Exchange (ETDEWEB)

    Ullmann, John Leonard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kawano, Toshihiko [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bredeweg, Todd Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Baramsai, Bayarbadrakh [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Couture, Aaron Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Haight, Robert Cameron [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jandel, Marian [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mosby, Shea Morgan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); O' Donnell, John M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rundberg, Robert S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Vieira, David J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wilhelmy, Jerry B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Becker, John A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wu, Ching-Yen [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Krticka, Milan [Charles Univ., Prague (Czech Republic)

    2015-05-28

    Neutron capture cross sections in the “continuum” region (>≈1 keV) and gamma-emission spectra are of importance to basic science and many applied fields. Careful measurements have been made on most common stable nuclides, but physicists must rely on calculations (or “surrogate” reactions) for rare or unstable nuclides. Calculations must be benchmarked against measurements (cross sections, gamma-ray spectra, and <Γγ>). Gamma-ray spectrum measurements from resolved resonances were made with 1 - 2 mg/cm2 thick targets; cross sections at >1 keV were measured using thicker targets. The results show that the shape of capture cross section vs neutron energy is not sensitive to the form of the strength function (although the magnitude is); the generalized Lorentzian E1 strength function is not sufficient to describe the shape of observed gamma-ray spectra; MGLO + “Oslo M1” parameters produces quantitative agreement with the measured 238U(n,γ) cross section; additional strength at low energies (~ 3 MeV) -- likely M1-- is required; and careful study of complementary results on low-lying giant resonance strength is needed to consistently describe observations.

  2. Standard cross-section data

    International Nuclear Information System (INIS)

    Carlson, A.D.

    1984-01-01

    The accuracy of neutron cross-section measurement is limited by the uncertainty in the standard cross-section and the errors associated with using it. Any improvement in the standard immediately improves all cross-section measurements which have been made relative to that standard. Light element, capture and fission standards are discussed. (U.K.)

  3. Neutron-capture cross-section measurement for 163Dy In the neutron energy range from 15 to 75 keV

    International Nuclear Information System (INIS)

    Kim, Hyun Duk; Jung, Eui Jung; Ahn, Jung Keun; Lee, Dae Won; Kim, Guin Yun; Ro, Tae Ik; Min, Young Ki; Igashira, Masayuki; Ohsaki, Toshiro; Mizuno, Satoshi

    2002-01-01

    The neutron-capture cross-section of 163 Dy were measured in the neutron energy range from 15 to 75 keV at the 3-MV Pelletron accelerator of the Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology. Pulsed neutrons were produced from the 7 Li(p,n) 7 Be reaction by bombarding a metallic lithium target with the 1.903-MeV proton beam. The incident neutron spectra were measured by means of a neutron time-of-flight method with a 6 Li-glass detector. Capture γ-rays were detected with a large anti-Compton NaI(Tl) spectrometer. A pulse-height weighting technique was applied to the capture γ-ray pulse-height spectra to obtain capture yields. The neutron capture cross-section were determined relative to the standard capture cross-sections of 197 Au. The present results were compared with the previous measurements and the evaluated values of ENDF/B-VI

  4. Determination of the neutron resonance parameters for 206Pb and of the thermal neutron capture cross section for 206Pb and 209Bi

    International Nuclear Information System (INIS)

    Borella, A.

    2005-01-01

    Chapter 1 describes the motivation of the measurements (accelerator driven systems, stellar nucleosynthesis, neutron induced reactions on 206 Pb), the present status of the neutron capture data for 206 Pb and 209 Bi and the structure of this work. In Chapter 2 the basic reaction theory underlying this work is described. The neutron induced reaction mechanism and formalism are explained. The parameterisation of the cross section in terms of R-matrix theory is discussed and we put particular emphasis on the statistical behaviour of the resonance parameters and the impact of the angular distribution of gamma rays following neutron capture. The relation between experimental observables and the resonance parameters is discussed together with general comments related to resonance shape analysis. Chapter 3 is focused on the determination of resonance parameters for 206 Pb. We performed high-resolution transmission and capture measurements at the Time-Of-Flight (TOF) facility GELINA of the IRMM at Geel (B) and determined the resonance parameters. For nuclei like 206 Pb, where the total width is dominated by Γ n , the capture area allows to determine G . Transmission measurements were carried out to determine Γ n , and the statistical factor g of resonances. Before performing a Resonance Shape Analysis (RSA) on the transmission and capture data, we verified the neutron flux and resolution at GELINA. We also compared the characteristics of GELINA with those of the n-TOF facility at CERN. A special emphasis is placed on the total energy detection technique using C 6 D 6 detectors. This technique was applied for the determination of the capture cross section. To reduce systematic bias effects on the capture cross section, the response of the detectors was determined by Monte Carlo simulations, which has been validated by experiments. Using these response functions the partial capture cross sections for individual resonances of 206 Pb have been deduced, by unfolding the

  5. Measurement and analysis of the 241Am neutron capture cross section at the n_TOF facility at CERN

    Science.gov (United States)

    Mendoza, E.; Cano-Ott, D.; Altstadt, S.; Andriamonje, S.; Andrzejewski, J.; Audouin, L.; Balibrea, J.; Bécares, V.; Barbagallo, M.; Bečvář, F.; Belloni, F.; Berthier, B.; Berthoumieux, E.; Billowes, J.; Bosnar, D.; Brugger, M.; Calviño, F.; Calviani, M.; Carrapiço, C.; Cerutti, F.; Chiaveri, E.; Chin, M.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Diakaki, M.; Dillmann, I.; Domingo-Pardo, C.; Durán, I.; Dzysiuk, N.; Eleftheriadis, C.; Ferrari, A.; Fraval, K.; Furman, V.; Gómez-Hornillos, M. B.; Ganesan, S.; García, A. R.; Giubrone, G.; Gonçalves, I. F.; González, E.; Goverdovski, A.; Gramegna, F.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Gurusamy, P.; Heftrich, T.; Heinitz, S.; Hernández-Prieto, A.; Heyse, J.; Jenkins, D. G.; Jericha, E.; Käppeler, F.; Kadi, Y.; Karadimos, D.; Katabuchi, T.; Ketlerov, V.; Khryachkov, V.; Koehler, P.; Kokkoris, M.; Kroll, J.; Krtička, M.; Lampoudis, C.; Langer, C.; Leal-Cidoncha, E.; Lederer, C.; Leeb, H.; Leong, L. S.; Lerendegui-Marco, J.; Licata, M.; López, D.; Losito, R.; Manousos, A.; Marganiec, J.; Martínez, T.; Massimi, C.; Mastinu, P.; Mastromarco, M.; Mengoni, A.; Milazzo, P. M.; Mingrone, F.; Mirea, M.; Mondelaers, W.; Paradela, C.; Pavlik, A.; Perkowski, J.; Plompen, A. J. M.; Praena, J.; Quesada, J. M.; Rauscher, T.; Reifarth, R.; Riego-Perez, A.; Robles, M.; Roman, F.; Rubbia, C.; Ryan, J. A.; Sabaté-Gilarte, M.; Sarmento, R.; Saxena, A.; Schillebeeckx, P.; Schmidt, S.; Schumann, D.; Sedyshev, P.; Tagliente, G.; Tain, J. L.; Tarifeño-Saldivia, A.; Tarrío, D.; Tassan-Got, L.; Tsinganis, A.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Vermeulen, M. J.; Versaci, R.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Ware, T.; Weigand, M.; Weiss, C.; Wright, T.; Žugec, P.; n TOF Collaboration

    2018-05-01

    The 241Am(n ,γ ) cross section has been measured at the n_TOF facility at CERN with the n_TOF BaF2 Total Absorption Calorimeter in the energy range between 0.2 eV and 10 keV. Our results are analyzed as resolved resonances up to 700 eV, allowing a more detailed description of the cross section than in the current evaluations, which contain resolved resonances only up to 150-160 eV. The cross section in the unresolved resonance region is perfectly consistent with the predictions based on the average resonance parameters deduced from the resolved resonances, thus obtaining a consistent description of the cross section in the full neutron energy range under study. Below 20 eV, our results are in reasonable agreement with JEFF-3.2 as well as with the most recent direct measurements of the resonance integral, and differ up to 20-30% with other experimental data. Between 20 eV and 1 keV, the disagreement with other experimental data and evaluations gradually decreases, in general, with the neutron energy. Above 1 keV, we find compatible results with previously existing values.

  6. Measurement of the radiative capture cross section of the s-process branching points 204Tl and 171Tm at the n_TOF facility (CERN)

    Science.gov (United States)

    Casanovas, A.; Domingo-Pardo, C.; Guerrero, C.; Lerendegui-Marco, J.; Calviño, F.; Tarifeño-Saldivia, A.; Dressler, R.; Heinitz, S.; Kivel, N.; Quesada, J. M.; Schumann, D.; Aberle, O.; Alcayne, V.; Andrzejewski, J.; Audouin, L.; Bécares, V.; Bacak, M.; Barbagallo, M.; Bečvář, F.; Bellia, G.; Berthoumieux, E.; Billowes, J.; Bosnar, D.; Brown, A.; Busso, M.; Caamaño, M.; Caballero-Ontanaya, L.; Calviani, M.; Cano-Ott, D.; Cerutti, F.; Chen, Y. H.; Chiaveri, E.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Cosentino, L.; Cristallo, S.; Damone, L. A.; Diakaki, M.; Dietz, M.; Dupont, E.; Durán, I.; Eleme, Z.; Fernández-Domínguez, B.; Ferrari, A.; Ferreira, P.; Finocchiaro, P.; Furman, V.; Göbel, K.; Gawlik, A.; Gilardoni, S.; Glodariu, T.; Gonçalves, I. F.; González-Romero, E.; Gunsing, F.; Heyse, J.; Jenkins, D. G.; Käppeler, F.; Kadi, Y.; Katabuchi, T.; Kimura, A.; Kokkoris, M.; Kopatch, Y.; Krtička, M.; Kurtulgil, D.; Ladarescu, I.; Lederer-Woods, C.; Meo, S. Lo; Lonsdale, S. J.; Macina, D.; Martínez, T.; Masi, A.; Massimi, C.; Mastinu, P.; Mastromarco, M.; Matteucci, F.; Maugeri, E. A.; Mazzone, A.; Mendoza, E.; Mengoni, A.; Michalopoulou, V.; Milazzo, P. M.; Mingrone, F.; Musumarra, A.; Negret, A.; Nolte, R.; Ogállar, F.; Oprea, A.; Patronis, N.; Pavlik, A.; Perkowski, J.; Persanti, L.; Porras, I.; Praena, J.; Radeck, D.; Ramos, D.; Rauscher, T.; Reifarth, R.; Rochman, D.; Sabaté-Gilarte, M.; Saxena, A.; Schillebeeckx, P.; Simone, S.; Smith, A. G.; Sosnin, N. V.; Stamatopoulos, A.; Tagliente, G.; Tain, J. L.; Talip, T.; Tassan-Got, L.; Tsinganis, A.; Ulrich, J.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Woods, P. J.; Wright, T.; Žugec, P.; Köster, U.

    2018-05-01

    The neutron capture cross section of some unstable nuclei is especially relevant for s-process nucleosynthesis studies. This magnitude is crucial to determine the local abundance pattern, which can yield valuable information of the s-process stellar environment. In this work we describe the neutron capture (n,γ) measurement on two of these nuclei of interest, 204Tl and 171Tm, from target production to the final measurement, performed successfully at the n_TOF facility at CERN in 2014 and 2015. Preliminary results on the ongoing experimental data analysis will also be shown. These results include the first ever experimental observation of capture resonances for these two nuclei.

  7. ENDF/B-5 fission product cross section evaluations

    International Nuclear Information System (INIS)

    Schenter, R.E.; England, T.R.

    1979-12-01

    Cross section evaluations were made for the 196 fission product nuclides on the ENDF/B-5 data files. Most of the evaluations involve updating the capture cross sections of the important absorbers for fast and thermal reactor systems. This included updating thermal values, resonance integrals, resonance parameter sets, and fast capture cross sections. For the fast capture results generalized least-squares calculations were made with the computer code FERRET. Input for these cross section adjustments included nuclear models calculations and both integral and differential experimental data results. The differential cross sections and their uncertainties were obtained from the CSIRS library. Integral measurement results came from CFRMF and STEK Assemblies 500, 1000, 2000, 3000, 4000. Comparisons of these evaluations with recent capture measurements are shown. 15 figures, 10 tables

  8. Measurement of the neutron capture cross section of U234 in n-TOF at CERN for Generation IV nuclear reactors

    International Nuclear Information System (INIS)

    Dridi, W.

    2006-11-01

    Accurate and reliable neutron capture cross sections are needed in many research areas, including stellar nucleosynthesis, advanced nuclear fuel cycles, waste transmutation, and other applied programs. In particular, the accurate knowledge of U 234 (n,γ) reaction cross section is required for the design and realization of nuclear power plants based on the thorium fuel cycle. We have measured the neutron capture cross section of U 234 , with a 4π BaF 2 Total Absorption Calorimeter, at the recently constructed neutron time-of-flight facility n-TOF at CERN in the energy range from 0.03 eV to 1 MeV. Monte-Carlo simulations with GEANT4 and MCNPX of the detector response have been performed. After the background subtraction and correction with dead time and pile-up, the capture yield from 0.03 eV up to 1.5 keV was derived. The analysis of the capture yield in terms of R-matrix resonance parameters is discussed. We have identified 123 resonances and measured the resonance parameters in the energy range from 0.03 eV to 1.5 keV. The mean radiative width γ > is found to be (38.2 ± 1.5) meV and the mean spacing parameter 0 > is (11.0 ± 0.2) eV, both values agree well with recommended values

  9. Capture cross-section measurements for different elements at neutron energies between 0.5 and 3.0 MeV

    International Nuclear Information System (INIS)

    Grenier, Gerard; Voignier, Jacques; Joly, Serge.

    1981-03-01

    Neutron capture cross-sections have been measured for the nuclides: Rb, Y, Nb, Gd, W, Pt, Tl, and for the isotopes 155 Gd, 156 Gd, 157 Gd, 158 Gd, 160 Gd, 182 W, 183 W, 184 W, 186 W, 203 Tl and 205 Tl in the 0.5 MeV to 3.0 MeV neutron energy range. Neutron capture cross-sections are determined through direct γ-ray spectrum emitted by the sample. The gamma-rays are detected by a NaI scintillator surrounded by an annular NaI detector. The time-of-flight method is used. Our results are compared with previous data, evaluations and statistical model calculations [fr

  10. Nuclear level densities and γ-ray strength functions of 180,181Ta and neutron capture cross sections

    Science.gov (United States)

    Malatji, K. L.; Kheswa, B. V.; Wiedeking, M.; Bello Garrote, F. L.; Brits, C. P.; Bleuel, D. L.; Giacoppo, F.; Görgen, A.; Guttormsen, M.; Hadynska-Klek, K.; Hagen, T. W.; Ingeberg, V. W.; Klintefjord, M.; Larsen, A. C.; Nyhus, H. T.; Renstrøm, T.; Rose, S.; Sahin, E.; Siem, S.; Tveten, G. M.; Zeiser, F.

    2017-09-01

    The γ-ray strength functions and nuclear level densities in the quasi-continuum of 180,181Ta are extracted from particle-γ coincidence events with the Oslo Method, below the Sn. The data were used as input in the TALYS reaction code for calculations of the astrophysical Maxwellian-averaged (n,γ) cross-sections to investigate nucleosynthesis of nature's rarest stable isotope 180Ta.

  11. Nuclear level densities and γ-ray strength functions of 180,181Ta and neutron capture cross sections

    Directory of Open Access Journals (Sweden)

    Malatji K.L.

    2017-01-01

    Full Text Available The γ-ray strength functions and nuclear level densities in the quasi-continuum of 180,181Ta are extracted from particle-γ coincidence events with the Oslo Method, below the Sn. The data were used as input in the TALYS reaction code for calculations of the astrophysical Maxwellian-averaged (n,γ cross-sections to investigate nucleosynthesis of nature's rarest stable isotope 180Ta.

  12. Total cross-sections for single electron capture from H, He and H2 targets by impact of Be4+ and B5+ ions

    International Nuclear Information System (INIS)

    Busnengo, H.F.; Rivarola, R.D.; Universidad Nacional de Rosario; Rosario Univ. Nacional

    1996-01-01

    Single electron capture from H, He and H 2 targets by impact of Be 4+ and B 5+ projectiles is studied for intermediate and high collision energies. Total cross-sections are calculated using the continuum distorted wave-eikonal final state model. Theoretical results corresponding to capture to selective final bound states and to all final states are presented for impact energies ranging from 50 keV/amu to 3 MeV/amu. A comparison with available experimental data is also shown. (orig.)

  13. A new approach for precise measurements of keV neutron capture cross sections: The examples of 93Nb, 103Rh, and 181Ta

    International Nuclear Information System (INIS)

    Wisshak, K.; Voss, F.; Kaeppeler, F.; Reffo, G.

    1990-04-01

    A new experimental method has been implemented for precise measurements of neutron capture cross sections in the energy range from 3 to 200 keV. Neutrons are produced via the 7 Li(p,n) 7 Be reaction using a pulsed 3 MV Van de Graaff accelerator. The neutron energy is determined by the time of flight technique using flight paths of less than 1 m. Capture events are detected with the Karlsruhe 4π Barium Fluoride Detector. This detector is characterized by a resolution in gamma-ray energy of 14% at 662 keV and 7% at 2.5 MeV, a time resolution of 500 ps, and a peak efficiency of 90% at 1 MeV. Capture events are registered with ≅ 95% probability above a gamma-ray threshold of 2.5 MeV. The combined effect of the relatively short primary flight path, the 10 cm inner radius of the detector sphere, and of the low capture cross section of BaF 2 allows to discriminate the main background due to capture of sample scattered neutrons in the scintillator via time of flight, leaving part of the neutron energy range completely undisturbed. The high efficiency and good energy resolution for capture gamma-rays yields a further reduction of this background by using only the relevant energy channels for data evaluation. In the first measurements with the new detector, the neutron capture cross sections of 93 Nb, 103 Rh, and 181 Ta were determined in the energy range from 3 to 200 keV relative to gold as a standard. The cross section ratios could be determined with overall systematic uncertainties of 0.7 to 0.8%; statistical uncertainties were less than 1% in the energy range from 20 to 100 keV, if the data are combined in 20 keV wide bins. The necessary sample masses were of the order of one gram. Further improvements with respect to sensitivity and accuracy are discussed. (orig.) [de

  14. Study on neutron capture cross sections using the filtered neutron beams of 55 keV and 144 keV at the Dalat reactor and related applications

    International Nuclear Information System (INIS)

    Vuong Huu Tan; Nguyen Canh Hai; Pham Ngoc Son; Tran Tuan Anh

    2007-01-01

    In this fundamental research project on nuclear physics in period of 2006, the neutron capture cross sections for the reactions of 139 La (n,γ) 140 La, 152 Sm (n,γ) 153 Sm, 191 Ir (n,γ) 192 Ir and 193 Ir (n,γ) 194 Ir have been measured at 55 keV and 144 keV by the activation method using the filtered neutron beams of the Dalat nuclear research reactor. The cross sections were determined relative to the standard capture cross sections of 197 Au. The samples and standard were prepaid from high purity (99.99%) foil of Au and natural oxide powders of La 2 O 3 , Sm 2 O 3 and IrO 2 . A high efficient HPGe detector (58%) was used to detect the gamma rays, emitted from the activated samples. The absolute efficiency curve of the detector has been precisely calibrated thanks to a set of standard radioisotope sources and a multi-nuclide standard solution, supported by IAEA. The present results were compared with the previous measurements from EXFOR-2003, and the evaluated values of JENDL 3.3 and ENDF/B-6.8. (author)

  15. 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.

  16. 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.

  17. Comparison of neutron capture cross sections obtained from two Hauser-Feshbach statistical models on a short-lived nucleus using experimentally constrained input

    Science.gov (United States)

    Lewis, Rebecca; Liddick, Sean; Spyrou, Artemis; Crider, Benjamin; Dombos, Alexander; Naqvi, Farheen; Prokop, Christopher; Quinn, Stephen; Larsen, Ann-Cecilie; Crespo Campo, Lucia; Guttormsen, Magne; Renstrom, Therese; Siem, Sunniva; Bleuel, Darren; Couture, Aaron; Mosby, Shea; Perdikakis, George

    2017-09-01

    A majority of the abundance of the elements above iron are produced by neutron capture reactions, and, in explosive stellar processes, many of these reactions take place on unstable nuclei. Direct neutron capture experiments can only be performed on stable and long-lived nuclei, requiring indirect methods for the remaining isotopes. Statistical neutron capture can be described using the nuclear level density (NLD), the γ strength function (γSF), and an optical model. The NLD and γSF can be obtained using the β-Oslo method. The NLD and γSF were recently determined for 74Zn using the β-Oslo method, and were used in both TALYS and CoH to calculate the 73Zn(n, γ)74Zn neutron capture cross section. The cross sections calculated in TALYS and CoH are expected to be identical if the inputs for both codes are the same, however, after a thorough investigation into the inputs for the 73Zn(n, γ)74Zn reaction there is still a factor of two discrepancy between the two codes.

  18. Simultaneous measurement of neutron-induced fission and capture cross sections for {sup 241}Am at neutron energies below fission threshold

    Energy Technology Data Exchange (ETDEWEB)

    Hirose, K., E-mail: hirose.kentaro@jaea.go.jp [Advanced Science Research Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan); Nishio, K.; Makii, H.; Nishinaka, I.; Ota, S. [Advanced Science Research Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan); Nagayama, T. [Advanced Science Research Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan); Graduate School of Science and Engineering, Ibaraki University, Mito 310-0056 (Japan); Tamura, N. [Advanced Science Research Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan); Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan); Goto, S. [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan); Andreyev, A.N. [Advanced Science Research Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan); Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom); Vermeulen, M.J. [Advanced Science Research Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan); Gillespie, S.; Barton, C. [Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom); Kimura, A.; Harada, H. [Nuclear Science and Engineering Center, JAEA, Tokai, Ibaraki 319-1195 (Japan); Meigo, S. [J-PARC Center, JAEA, Tokai, Ibaraki 319-1195 (Japan); Chiba, S. [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Tokyo 152-8550 (Japan); Ohtsuki, T. [Research Reactor Institute, Kyoto University, Kumatori-cho S' ennangun,Osaka 590-0494 (Japan)

    2017-06-01

    Fission and capture reactions were simultaneously measured in the neutron-induced reactions of {sup 241}Am at the spallation neutron facility of the Japan Proton Accelerator Research Complex (J-PARC). Data for the neutron energy range of E{sub n}=0.1–20 eV were taken with the TOF method. The fission events were observed by detecting prompt neutrons accompanied by fission using liquid organic scintillators. The capture reaction was measured by detecting γ rays emitted in the deexcitation of the compound nuclei using the same detectors, where the prompt fission neutrons and capture γ rays were separated by a pulse shape analysis. The cross sections were obtained by normalizing the relative yields at the first resonance to evaluations or other experimental data. The ratio of the fission to capture cross sections at each resonance is compared with those from an evaluated nuclear data library and other experimental data. Some differences were found between the present values and the library/literature values at several resonances.

  19. Tables of RCN-2 fission-product cross section evaluation

    International Nuclear Information System (INIS)

    Gruppelaar, H.

    1979-05-01

    This report (continuation of ECN-13 and ECN-33) describes the third part of the RCN-2 evaluation of neutron cross sections for fission product nuclides in KEDAK format. It contains evaluated data for nine nuclides, i.e. 142 Nd, 143 Nd, 144 Nd, 145 Nd, 146 Nd, 147 Nd, 148 Nd, 150 Nd and 147 Pm. Most emphasis has been given to the evaluation of the radiative capture cross section, in order to provide a data base for adjustment calculations using results of integral measurements. Short evaluation reports are given for this cross section. The evaluated capture cross sections are compared with recent experimental differential and integral data. Graphs are given of the capture cross sections at neutron energies above 1 keV, in which also adjusted point cross sections, based upon integral STEK and CFRMF data have been plotted. Moreover, the results are compared with those of the well-known ENDF/B-IV evaluation for fission product nucleides. Finally, evaluation summaries are given, which include tables of other important neutron cross sections, such as the total, elastic scattering and inelastic scattering cross sections

  20. Thermal neutron capture cross-section measurements of 243Am and 242Pu using the new mini-INCA α- and γ-spectroscopy station

    International Nuclear Information System (INIS)

    Marie, F.; Letourneau, A.; Fioni, G.; Deruelle, O.; Veyssiere, Ch.; Faust, H.; Mutti, P.; AlMahamid, I.; Muhammad, B.

    2006-01-01

    In the framework of the Mini-INCA project, dedicated to the study of Minor Actinide transmutation process in high neutron fluxes, an α- and γ-spectroscopy station has been developed and installed at the High Flux Reactor of the Laue-Langevin Institut. This set-up allows short irradiations as well as long irradiations in a high quasi-thermal neutron flux and post-irradiation spectroscopy analysis. It is well suited to measure precisely, in reference to 59 Co cross-section, neutron capture cross-sections, for all the actinides, in the thermal energy region. The first measurements using this set-up were done on 243 Am and 242 Pu isotopes. Cross-section values, at E n =0.025eV, were found to be (81.8+/-3.6)b for 243 Am and (22.5+/-1.1)b for 242 Pu. These values differ from evaluated data libraries by a factor of 9% and 17%, respectively, but are compatible with the most recent measurements, validating by the way the experimental apparatus

  1. Real-Time Monitoring of Neutron Capture Cross Section in the IPR-R1 TRIGA Research Reactor as a Fuel Temperature Function

    Energy Technology Data Exchange (ETDEWEB)

    Palma, D.A.P. [Comissao Nacional de Energia Nuclear, CNEN, General Severiano Street, 90, 22290-901, Rio de Janeiro (Brazil); Mesquita, A.Z.; Souza, R.M.G.P. [Comissao Nacional de Energia Nuclear, CNEN/CDTN, Av. Presidente Antonio Carlos, 6627, 31270-901, Belo Horizonte (Brazil); Martinez, A.S. [Programa de Engenharia Nuclear, COPPE/UFRJ, Av. Horacio Macedo, 2030, Bloco G, 21941- 914, Rio de Janeiro (Brazil)

    2011-07-01

    Nuclear reactor operators have to monitor the behaviour of different nuclear and design parameters that vary in time to ensure the operating safety of the reactor. In recent years several operating parameters for the IPR-R1 TRIGA research reactor were monitored and indicated in real-time by the data acquisition system developed for the reactor, with all the data being stored in a hard disk in the data acquisition computer, to build in this way a database. The goal of this work is to insert in the set of parameters already collected the neutron capture cross sections for the fuel, from the power and temperature numbers obtained in real-time. The experimental data was obtained by using a fuel element instrumented with temperature sensors, located in the core of the IPR-R1 TRIGA research reactor at the CDTN - Centre for Development of Nuclear. This information is useful for the continuous monitoring of the reaction rate in neutron capture. For that, a new analytical formulation is used for the Doppler broadening function proposed by Palma and Martinez which is free from special functions in its functional form and with easy computing implementation. The results obtained were satisfactory from the standpoint of accuracy in comparison with the numerical reference method and indicate that it is possible to carry out real-time monitoring of the neutron capture cross section in the fuel. (author)

  2. Neutron capture cross sections of 69Ga and 71Ga at 25 keV and Epeak = 90 keV

    Directory of Open Access Journals (Sweden)

    Göbel Kathrin

    2017-01-01

    Full Text Available We measured the neutron capture cross sections of 69Ga and 71Ga for a quasi-stellar spectrum at kBT = 25 keV and a spectrum with a peak energy at 90 keV by the activation technique at the Joint Research Centre (JRC in Geel, Belgium. Protons were provided by an electrostatic Van de Graaff accelerator to produce neutrons via the reaction 7Li(p,n. The produced activity was measured via the γ emission of the product nuclei by high-purity germanium detectors. We present preliminary results.

  3. Neutron capture cross sections of 69Ga and 71Ga at 25 keV and Epeak = 90 keV

    Science.gov (United States)

    Göbel, Kathrin; Beinrucker, Clemens; Erbacher, Philipp; Fiebiger, Stefan; Fonseca, Micaela; Heftrich, Michael; Heftrich, Tanja; Käppeler, Franz; Krása, Antonin; Lederer-Woods, Claudia; Plag, Ralf; Plompen, Arjan; Reifarth, René; Schmidt, Stefan; Sonnabend, Kerstin; Weigand, Mario

    2017-09-01

    We measured the neutron capture cross sections of 69Ga and 71Ga for a quasi-stellar spectrum at kBT = 25 keV and a spectrum with a peak energy at 90 keV by the activation technique at the Joint Research Centre (JRC) in Geel, Belgium. Protons were provided by an electrostatic Van de Graaff accelerator to produce neutrons via the reaction 7Li(p,n). The produced activity was measured via the γ emission of the product nuclei by high-purity germanium detectors. We present preliminary results.

  4. A Study of the Energy Dependence of the Th 232 Capture Cross Section in the Energy Region 0.1 to 3.4 eV

    Energy Technology Data Exchange (ETDEWEB)

    Lundgren, G

    1967-11-15

    Using the fast chopper at the Stockholm reactor R1 a comparison between the (n, {gamma}) cross sections for thorium and copper has been made in the energy interval 0.1 to 3.4 eV. The (n, {gamma}) cross section for copper follows the 1/v law sufficiently well in this energy interval to be used as a 1/v standard. The deviation at 3.4 eV does not exceed 5 %. The capture cross section, {sigma}, for thorium decreases more rapidly than 1/v and the deviation is found to be close to 60 % at 3.4 eV. If one assumes that the deviation is caused essentially by a single negative resonance this should be located at 5.1 {+-} 0.5 eV. Furthermore, if a value of 24 meV for {gamma}{sub {gamma}}, the radiation width for the negative resonance, is used one finds that {gamma}{sub n}{sup 0}, the reduced neutron width for the same resonance, amounts to 1.82 {+-} 0.25 meV. Using these parameters together with the resonance parameters for the positive resonances a value of the total microscopic scattering cross section at 0.025 eV has been calculated as 12.2 {+-} 0.4 b. A value of the contributions above 0.5 eV to the resonance integral from the 'tail' of the negative resonance and the 1/v - parts of the positive resonances has also been calculated giving the result 1.6 b. Finally, the g-factor (Westcott's nomenclature) for a Maxwellian spectrum at 20 deg C becomes 0.994.

  5. Development of the next generation code system as an engineering modeling language (6). Development of a cross section adjustment and nuclear design accuracy evaluation solver

    International Nuclear Information System (INIS)

    Yokoyama, Kenji; Numata, Kazuyuki

    2008-01-01

    A new cross section adjustment and nuclear design accuracy evaluation solver was developed as a set of modules for MARBLE (multi-purpose advanced reactor physics analysis system based on language of engineering). In order to enhance the system extendibility and flexibility, the object-oriented design and analysis technique was adopted to the development. In the new system, it is easy to add a new design accuracy evaluation method because a new numerical calculation module is independent from other modules. Further, several new functions such as searching and editing calculation data are provided in the new solver. These functions can be easily customised by users because they are designed to work cooperatively with Python scripting language, which is used as a user interface of the MARBLE system. In order to validate the new solver, a test calculation was performed for a realistic calculation case of creating a new unified cross section library. In the test calculation, results calculated by the new solver agreed well with those by the conventional code system. In addition, it is possible to reuse existing input data files prepared for the conventional code system because the new solver utilities support the conventional formats. Because the new solver implements all main functions of the conventional code system, MARBLE can be used as a new calculation code system for cross section adjustment and nuclear design accuracy evaluation

  6. Fast neutron capture cross sections of /sup 169/Tm, /sup 191/Ir, /sup 193/Ir, and /sup 175/Lu for 3 less than or equal to E/sub n/ less than or equal to 2000 keV

    Energy Technology Data Exchange (ETDEWEB)

    Macklin, R.L.; Drake, D.M.; Malanify, J.J.

    1977-11-01

    Fast neutron capture cross sections of /sup 169/Tm, /sup 191/Ir, /sup 193/Ir, and /sup 175/Lu, and the /sup 6/Li(n,..cap alpha..)/sup 3/H cross sections to which they are normalized are presented in tabular form for neutron energies between 3 and 2000 keV.

  7. Large electron capture-cross-section of the major nonradiative recombination centers in Mg-doped GaN epilayers grown on a GaN substrate

    Science.gov (United States)

    Chichibu, S. F.; Shima, K.; Kojima, K.; Takashima, S.; Edo, M.; Ueno, K.; Ishibashi, S.; Uedono, A.

    2018-05-01

    Complementary time-resolved photoluminescence and positron annihilation measurements were carried out at room temperature on Mg-doped p-type GaN homoepitaxial films for identifying the origin and estimating the electron capture-cross-section ( σ n ) of the major nonradiative recombination centers (NRCs). To eliminate any influence by threading dislocations, free-standing GaN substrates were used. In Mg-doped p-type GaN, defect complexes composed of a Ga-vacancy (VGa) and multiple N-vacancies (VNs), namely, VGa(VN)2 [or even VGa(VN)3], are identified as the major intrinsic NRCs. Different from the case of 4H-SiC, atomic structures of intrinsic NRCs in p-type and n-type GaN are different: VGaVN divacancies are the major NRCs in n-type GaN. The σ n value approximately the middle of 10-13 cm2 is obtained for VGa(VN)n, which is larger than the hole capture-cross-section (σp = 7 × 10-14 cm2) of VGaVN in n-type GaN. Combined with larger thermal velocity of an electron, minority carrier lifetime in Mg-doped GaN becomes much shorter than that of n-type GaN.

  8. Summary Report of the Technical Meeting on Inelastic Scattering and Capture Cross-section Data of Major Actinides in the Fast Neutron Region

    International Nuclear Information System (INIS)

    Plompen, Arjan; Kawano, Toshihiko; Capote Noy, Roberto

    2012-05-01

    Recently, tight target uncertainties on the capture and inelastic scattering data for major actinides were derived from advanced reactor sensitivity studies. A Technical Meeting on 'Inelastic Scattering and Capture Cross-section Data of Major Actinides in the Fast Neutron Region' was held at IAEA Headquarters, Vienna, Austria to review the status of nuclear data libraries for these cross sections, the status of the experimental results by which these can be tested and to evaluate what advances in nuclear modeling and measurement technique may bring to improve the knowledge of these cross sections. The participants compared recent evaluations with various modeling approaches that have not yet been adopted in data libraries. Several points of interest were found. First, different evaluations may show very similar performance for macroscopic benchmarks. Second, recent modeling improvements from different communities and using different codes tend to converge on the principles in the case of coupled channel calculations. In particular, it was shown that meaningful results require convergence with respect to the number of coupled channels and the use of the dispersive coupled channels potential based with an isospin dependent term to treat neutrons and protons in a coherent manner appears to be uncontested. Also, the issue regarding the use of transmission coefficients from coupled channels calculations in the Hauser Feshbach model was tackled. Recent and ongoing experimental efforts were presented for capture and inelastic scattering on the major actinides. Results from these are likely to become available in a period from 2 to 5 years. A discussion on the representation of the data in EXFOR revealed that care must be taken interpreting the numbers given in the case of inelastic scattering. It has been a long time since capture data were obtained for fissile nuclei and it is exciting to find new efforts are being considered at LANL, CERN and CENBG/IRMM. It was finally

  9. Erratum: Extracting (n,γ) direct capture cross sections from Coulomb dissociation: application to 14C(n,γ)15C

    International Nuclear Information System (INIS)

    Summers, N.C.; Nunes, F.M.

    2008-01-01

    In Ref. (1) we proposed a systematic methodology to extract neutron capture cross sections from Coulomb Dissociation data. Using the Continuum Discretized Coupled Channel formalism to describe the 15 C breakup process, the asymptotic normalization coefficient (ANC) for the ground state is extracted through a χ 2 fit. The corresponding error bar is defined using χ min 2 + 1. We discovered a mistake in the calculation of the errors associated with the extracted ANC and here we present the corrected values. The experimental data from which the ANC is extracted covers a range of energies up to 4 MeV, and the value obtained for the full energy range is C 0 = 1.31 ± 0.07 fm -1/2 . We find that the ANC is better determined if the high energy data is discarded and the maximum energy is cut at 1.2 MeV. This is justified since the direct measurements we are comparing to, and the peak of the cross section (Fig. 1 in Ref. (1)), all lie below this cut. The higher energy data is more uncertain and lies in a region where the theoretical cross section is insensitive to the ANC, thus adding unwarranted uncertainty to the extracted ANC. With this energy cut one can better determine the ANC as C 0 = 1.32 ± 0.04 fm -1/2 . All conclusions in our previous paper (1) hold. More details on the fitting procedure can be found in Ref. (2). Figure 2 of Ref. (1) should be replaced by the figure below, where the shaded area is the range of uncertainty for an ANC of C 0 = 1.32 ± 0.04 fm -1/2 , extracted from data up to E = 1.2 MeV

  10. 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.

  11. Single electron ionization and electron capture cross sections for (C{sup 6+}, H{sub 2}O) interaction within the Classical Trajectory Monte Carlo (CTMC) approach

    Energy Technology Data Exchange (ETDEWEB)

    Tran, H.N., E-mail: tranngochoang@tdt.edu.vn [Division of Nuclear Physics, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Dao, D.D. [Division of Nuclear Physics, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Incerti, S. [Division of Nuclear Physics, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Université de Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); Bernal, M.A. [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, SP (Brazil); Karamitros, M. [CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Université de Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); Nhan Hao, T.V. [Center of Research and Development, Duy Tan University, K7/25 Quang Trung, Danang (Viet Nam); Center for Theoretical and Computational Physics, College of Education, Hue University, 34 Le Loi Street, Hue City (Viet Nam); Dang, T.M. [VNUHCM-University of Science (Viet Nam); Francis, Z. [Saint Joseph University, Beyrouth (Lebanon)

    2016-01-01

    In this work, we present a derivation of cross sections for single ionization and electron capture processes within the Classical Trajectory Monte Carlo (CTMC) approach. Specifically, we have used a potential stemming from an ab initio calculation in Green et al.’s framework to describe the dynamics of the water molecule system. Proposing a modified version of the Classical Over-Barrier (COB) potential, we have found that a cut-off of roughly 28 a.u. on the initial distance of the projectile produced a reasonable accuracy. A global agreement has been obtained in our calculations compared to experimental and other theoretical results for C{sup 6+} ion energies ranging from 10 keV/u to 10 MeV/u.

  12. Application of modified REFIT code for J-PARC/MLF to evaluation of neutron capture cross section on 155,157Gd

    Science.gov (United States)

    Mizuyama, Kazuhito; Iwamoto, Nobuyuki; Iwamoto, Osamu; Hasemi, Hiroyuki; Kino, Koichi; Kimura, Atsushi; Kiyanagi, Yoshiaki

    2017-09-01

    In order to analyze the experimental data measured by the Accurate Neutron-Nucleus Reaction Measurement Instrument (ANNRI) at the Japan Proton Accelerator Research Complex/Materials and Life Science Experimental Facility (J-PARC/MLF), it is necessary to take into account the double-bunch structure of the neutron pulse and the energy resolution function for the operational condition of the J-PARC/MLF. The modified REFIT code has been developed to treat the double-bunch neutron pulse and the energy resolution function for J-PARC/MLF. In this study, we applied the modified REFIT code to analyze the new data of the neutron capture cross section of 155Gd and 157Gd recently measured by ANNRI in the J-PARC/MLF, and obtained the resonance parameters of two Gd isotopes. We discussed the differences between the our obtained results and the other libraries.

  13. Measurement of the {sup 232}thorium capture cross section at n-TOF-CERN; Mesure de la section efficace de capture neutronique du {sup 232}Th a n-TOF au CERN

    Energy Technology Data Exchange (ETDEWEB)

    Aerts, G

    2005-09-01

    Within the context of nuclear power as a sustainable energy resource, a program of research is concentrated on a new nuclear fuel cycle based on thorium. The main advantage, as compared to the uranium cycle, is a lower production of minor actinides, of which the radiological impact on the long term constitutes a problem. At present, nuclear data libraries don't provide cross sections of a good enough quality, allowing more realistic calculations from simulations related to these reactors. The {sup 232}Th neutron capture cross section is an example. With the n-TOF collaboration, the measurement of this reaction was achieved in 2002 using two C{sub 6}D{sub 6} detectors. The experimental area located at CERN, is characterized by an outstanding neutron energy resolution coupled to a high instantaneous neutron flux. The determination of the gamma-ray cascade detection efficiency, with a random behaviour, has been obtained by the use of weighting functions. These were deduced from Monte Carlo simulations with the code MCNP. Data extraction, reduction, and the description of the neutron flux have lead to the capture yield. In the resolved resonance region, the resonance parameters describing the cross section were deduced with the code SAMMY, using the R-matrix theory. In the unresolved resonance region, an uncertainty of 3,5% is found, and a comparison with recent measurements shows a good agreement. (author)

  14. Experimental cross sections for two-electron capture into nitrogen autoionising states in Nsup(q+) (q=6,7) on He and H/sub 2/ collisions at 10. 5q keV

    Energy Technology Data Exchange (ETDEWEB)

    Bordenave-Montesquieu, A.; Benoit-Cattin, P.; Gleizes, A.; Marrakchi, A.I.; Dousson, S.; Hitz, D.

    1985-07-01

    Singly differential cross sections for two-electron capture into autoionising states (nl,n'l') with n=2,3,4 and n'>=n in Nsup(q+) (q=6,7) on He and H/sub 2/ collisions have been measured at 10,5q ke V collision energy and an observation angle thetasub(lab)=11.6/sup 0/. Total cross sections are estimated assuming isotropic angular distributions. (orig.).

  15. Experimental cross sections for two-electron capture into nitrogen autoionising states in Nsup(q+) (q=6,7) on He and H2 collisions at 10.5q keV

    International Nuclear Information System (INIS)

    Bordenave-Montesquieu, A.; Benoit-Cattin, P.; Gleizes, A.; Marrakchi, A.I.

    1985-01-01

    Singly differential cross sections for two-electron capture into autoionising states (nl,n'l') with n=2,3,4 and n'>=n in Nsup(q+) (q=6,7) on He and H 2 collisions have been measured at 10,5q ke V collision energy and an observation angle thetasub(lab)=11.6 0 . Total cross sections are estimated assuming isotropic angular distributions. (orig.)

  16. FEMA DFIRM Cross Sections

    Data.gov (United States)

    Minnesota Department of Natural Resources — FEMA Cross Sections are required for any Digital Flood Insurance Rate Map database where cross sections are shown on the Flood Insurance Rate Map (FIRM). Normally...

  17. L2 Milestone: Neutron Capture Cross Sections from Surrogate (p, d) Measurements: Determination of the Unknown 87Y(n, g) Cross Section and Assessment of the Method Via the 90Zr(n, g) Benchmark Case: Theory Report

    Energy Technology Data Exchange (ETDEWEB)

    Escher, J. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-09-06

    Cross sections for compound-nuclear reactions involving unstable targets are important for many applications, but can often not be measured directly. Here we describe a method for extracting cross sections for neutron-capture on unstable isotopes from indirect (surrogate) measurements. The surrogate reaction, which produces the compound nucleus of interest, has to be described and the decay of the nucleus has to be modeled. We outline the approach for one-neutron pickup and report on the determination of the 90Zr(n, γ ) reaction from surrogate 92Zr(p,d) data, which is compared to the directly-measured capture cross section and thus provides a benchmark for the method. We then apply the method to determine the 87Y(n, γ ) cross section, which has not been measured directly. The work was carried out in the context of an LLNL L2 Milestone. This report addresses the theory aspects of the milestone. A complementary document summarizes the experimental efforts [1].

  18. A Cross-sectional Study to Determine Whether Adjustment to an Ostomy Can Predict Health-related and/or Overall Quality of Life.

    Science.gov (United States)

    Indrebø, Kirsten Lerum; Natvig, Gerd Karin; Andersen, John Roger

    2016-10-01

    Ostomy-specific adjustment may or may not predict health-related quality of life (HRQoL) and/or overall quality of life (QoL). A cross-sectional study was conducted among patients recruited from the customer registers of 8 surgical suppliers and pharmacies across Norway between November 2010 and March 2011 to determine which of the 34 items of the Ostomy Adjustment Scale (OAS) are the strongest predictors for HRQoL and overall QoL and to determine the HRQoL and overall QoL of individuals with an ostomy compared to a control group representing the general population. Persons who were >18 years old; had a permanent colostomy, ileostomy, or urostomy for >3 months; and could read and write Norwegian were invited to participate. The participants received information about the study in a letter from the researcher and returned their demographic information (addressing gender, age, marital status, education, diagnosis, time since surgery, and ostomy type) and study questionnaires using prepaid envelopes. The 158 participants (mean age 64 years [range 29-91], 89 [56%] men and 69 [44%] women) completed and returned by mail a sociodemographic questionnaire, the 34-item OAS (questions scored on a scale of 1 to 6, totally disagree to totally agree, score range 34 to 204), the Short Form-36 (SF-36, including 2 main components [physical and mental issues] divided into 8 subscales, scored from 0 to 100), and the 16-item Quality of Life Scale (QOLS) instrument (each response scored 1 to 7, from very dissatisfied to very satisfied; total score ranging from 16 to 112). Statistical analysis, including ordinary least square regression analyses, assessed whether the OAS independently predicted the sum scores of the SF-36 (physical component summary [PCS] and mental component summary [MCS]) and the QOLS score after adjusting for age, gender, marital status, education, diagnosis, time since surgery, and ostomy type. The OAS significantly predicted the SF-36 (PCS and MCS) and QOLS scores

  19. Evaluated cross section libraries

    International Nuclear Information System (INIS)

    Maqurno, B.A.

    1976-01-01

    The dosimetry tape (ENDF/B-IV tape 412) was issued in a general CSEWG distribution, August 1974. The pointwise cross section data file was tested with specified reference spectra. A group averaged cross section data file (620 groups based on tape 412) was tested with the above spectra and the results are presented in this report

  20. Jet inclusive cross sections

    International Nuclear Information System (INIS)

    Del Duca, V.

    1992-11-01

    Minijet production in jet inclusive cross sections at hadron colliders, with large rapidity intervals between the tagged jets, is evaluated by using the BFKL pomeron. We describe the jet inclusive cross section for an arbitrary number of tagged jets, and show that it behaves like a system of coupled pomerons

  1. Production of a {sup 44} Ti target and its cross section of thermal neutron capture; Producao de um alvo de {sup 44} Ti e sua secao de choque para captura de neutrons termicos

    Energy Technology Data Exchange (ETDEWEB)

    Ejnisman, R

    1994-12-31

    A study of the production of a {sup 44} Ti target was carried out aiming the determination of its thermal neutron capture cross-section. With this purpose, the cross-section of the reaction {sup 45} Sc(p,2 n) {sup 44} Ti was determined in the energies 16-, 18-, 20-22- and 45 MeV. The cross-section of the reactions (p,n) {sup 45} Ti, (p,pn) {sup 44m} Sc, (p,pn) {sup 44g} Sc and (p,p2n){sup 43} Sc were also measured. The results in the low energy region are in good agreement with a previous work by McGee et al. On the other hand, the cross-section at 45 MeV is different from McGee`s result and indicates the existence of an abnormal behavior of the excitation function at higher energies. Furthermore, a radiochemical separation method was developed in order to eliminate Sc from the {sup 44} Ti target which was irradiated with neutrons. It was possible to determine an upper limit for the cross-section of the reaction {sup 44} Ti (n, {gamma}) of 4 x 10{sup 3} b. At last, it is presented a discussion of the results obtained and their possible astrophysical implications. (author) 94 refs.

  2. K-shell x-ray production cross sections of selected elements Al to Ni for 4. 0 to 38. 0 MeV /sup 10/B ions. [Cross sections, 4. 0 to 38 MeV, binding energy, electron capture decay, PWBA, energy shifts, multiple ionization

    Energy Technology Data Exchange (ETDEWEB)

    Monigold, G.; McDaniel, F.D.; Duggan, J.L.; Mehta, R.; Rice, R.; Miller, P.D.

    1976-01-01

    K-Shell x-ray production cross sections for the target elements Sc, Ti, V, Mn, Fe, Co, and Ni were measured for incident /sup 10/B ions over the energy range 4.0 to 38.0 MeV. The cross section data were compared to the theoretical predictions of the binary encounter approximation (BEA); the plane wave born approximation (PWBA); and the PWBA modified to include corrections for increased binding energy (B), Coulomb deflection of the incident ion (C), orbital perturbation due to polarization (P), and relativistic effects (R). In addition, fluorescence yield variations (W/sub K/) and contributions to the cross sections from electron capture (EC) were included. It was found that the predictions of the fully modified PWBA with contributions from electron capture and fluorescence yield variations included provided the best fit to the experimental data over the entire energy range for each target element. The K..beta../K..cap alpha.. x-ray intensity ratios were compared to theoretical values that assume single hole ionization, and the x-ray energy shifts presented as a function of the energy of the incident ion. These two measurements provided confirmation of the occurrence of multiple ionization for /sup 10/B bombardment of target elements in the range 21 less than or equal to Z/sub 2/ less than or equal to 28.

  3. Curves and tables of neutron cross sections

    International Nuclear Information System (INIS)

    Nakagawa, Tsuneo; Asami, Tetsuo; Yoshida, Tadashi

    1990-07-01

    Neutron cross-section curves from the Japanese Evaluated Nuclear Data Library version 3, JENDL-3, are presented in both graphical and tabular form for users in a wide range of application areas in the nuclear energy field. The contents cover cross sections for all the main reactions induced by neutrons with an energy below 20 MeV including; total, elastic scattering, capture, and fission, (n,n'), (n,2n), (n,3n), (n,α), (n,p) reactions. The 2200 m/s cross-section values, resonance integrals, and Maxwellian- and fission-spectrum averaged cross sections are also tabulated. (author)

  4. Neutron cross sections for uranium-235 (ENDF/B-IV Release 3)

    International Nuclear Information System (INIS)

    Lubitz, C.R.

    1996-09-01

    The resonance parameters in ENDF6 (Release 2) U235 were adjusted to make the average capture and fission cross sections below 900 eV agree with selected differential capture and fission measurements. The measurements chosen were the higher of the credible capture measurements and the lower of the fission results, yielding a higher epithermal alpha. In addition, the 2200 m/s cross sections were adjusted to obtain agreement with the integral value of K1. As a result, criticality calculations for thermal benchmarks, and agreement with a variety of integral parameters, are improved

  5. Floodplain Cross Section Lines

    Data.gov (United States)

    Department of Homeland Security — This table is required for any Digital Flood Insurance Rate Map database where cross sections are shown on the Flood Insurance Rate Map (FIRM). Normally any FIRM...

  6. Multitrajectory eikonal cross sections

    International Nuclear Information System (INIS)

    Turner, R.E.

    1983-01-01

    With the use of reference and distorted transition operators, a time-correlation-function representation of the inelastic differential cross section has recently been used to obtain distorted eikonal cross sections. These cross sections involve straight-line and reference classical translational trajectories that are unaffected by any internal-state changes which have occurred during the collision. This distorted eikonal theory is now extended to include effects of internal-state changes on the translational motion. In particular, a different classical trajectory is associated with each pair of internal states. Expressions for these inelastic cross sections are obtained in terms of time-ordered cosine and sine memory functions using the Zwanzig-Feshbach projection-operator method. Explicit formulas are obtained in the time-disordered perturbation approximation

  7. Measurement of the neutron-capture cross section on 63,65Cu between 0.4 and 7.5 MeV

    Science.gov (United States)

    Bray, Isabel; Bhike, Megha; Krishichayan, (None); Tornow, W.

    2015-10-01

    Copper is currently being used as a cooling and shielding material in most experimental searches for 0 ν β β decay. In order to accurately interpret background events in these experiments, the cross section of neutron-induced reactions on copper must be known. The purpose of this work was to measure the cross section of the 63,65Cu(n, γ)64,66Cu reactions. Data were collected through the activation method at a range of energies from approximately 0.4 MeV to 7.5 MeV, employing the neutron production reactions 3H(p,n)3Heand2H(d,n)3He. Previous data were limited to energies below approximately 3 MeV. The results are compared to predictions from the nuclear data libraries ENDF/B-VII.1 and TENDL-2014.

  8. MANTA. An Integral Reactor Physics Experiment to Infer the Neutron Capture Cross Sections of Actinides and Fission Products in Fast and Epithermal Spectra

    Energy Technology Data Exchange (ETDEWEB)

    Youinou, Gilles Jean-Michel [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-10-01

    Neutron cross-sections characterize the way neutrons interact with matter. They are essential to most nuclear engineering projects and, even though theoretical progress has been made as far as the predictability of neutron cross-section models, measurements are still indispensable to meet tight design requirements for reduced uncertainties. Within the field of fission reactor technology, one can identify the following specializations that rely on the availability of accurate neutron cross-sections: (1) fission reactor design, (2) nuclear fuel cycles, (3) nuclear safety, (4) nuclear safeguards, (5) reactor monitoring and neutron fluence determination and (6) waste disposal and transmutation. In particular, the assessment of advanced fuel cycles requires an extensive knowledge of transuranics cross sections. Plutonium isotopes, but also americium, curium and up to californium isotope data are required with a small uncertainty in order to optimize significant features of the fuel cycle that have an impact on feasibility studies (e.g. neutron doses at fuel fabrication, decay heat in a repository, etc.). Different techniques are available to determine neutron cross sections experimentally, with the common denominator that a source of neutrons is necessary. It can either come from an accelerator that produces neutrons as a result of interactions between charged particles and a target, or it can come from a nuclear reactor. When the measurements are performed with an accelerator, they are referred to as differential since the analysis of the data provides the cross-sections for different discrete energies, i.e. σ(Ei), and for the diffusion cross sections for different discrete angles. Another approach is to irradiate a very pure sample in a test reactor such as the Advanced Test Reactor (ATR) at INL and, after a given time, determine the amount of the different transmutation products. The precise characterization of the nuclide densities before and after

  9. Thermal Neutron Capture and Thermal Neutron Burn-up of K isomeric state of 177mLu: a way to the Neutron Super-Elastic Scattering cross section

    International Nuclear Information System (INIS)

    Roig, O.; Belier, G.; Meot, V.; Daugas, J.-M.; Romain, P.; Aupiais, J.; Jutier, Ch.; Le Petit, G.; Letourneau, A.; Marie, F.; Veyssiere, Ch.

    2006-01-01

    Thermal neutron radiative capture and burn-up measurements of the K isomeric state in 177Lu form part of an original method to indirectly obtain the neutron super-elastic scattering cross section at thermal energy. Neutron super-elastic scattering, also called neutron inelastic acceleration, occurs during the neutron collisions with an excited nuclear level. In this reaction, the nucleus could partly transfer its excitation energy to the scattered neutron

  10. Thermal neutron capture cross-section and resonance integral measurements of {sup 139}La(n, γ){sup 140}La and {sup 140}Ce(n, γ){sup 141}Ce using a Am-Be neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Panikkath, Priyada; Mohanakrishnan, P. [Manipal University, Manipal Centre for Natural Sciences, Karnataka (India)

    2017-03-15

    Thermal neutron capture cross-sections and resonance integrals of {sup 139}La(n, γ){sup 140}La and {sup 140}Ce (n, γ){sup 141}Ce are measured with respect to reference reactions {sup 197}Au(n, γ){sup 198}Au and {sup 55}Mn(n, γ){sup 56}Mn using the neutron activation technique. Measurements are carried out using neutrons from an Am-Be source located inside a concrete bunker. Two different methods are used for determining self-shielding factors of activation foils as well as for finding the epithermal neutron spectrum shape factor. For {sup 139}La with reference to {sup 197}Au and {sup 55}Mn the measured thermal cross sections are 9.24 ± 0.25 b and 9.28 ± 0.37 b, respectively, while the measured resonance integrals are 12.18 ± 0.67 b and 11.81 ± 0.94 b, respectively. For {sup 140}Ce with reference to {sup 197}Au and {sup 55}Mn the measured thermal cross sections are 0.44 ± 0.01 b and 0.44 ± 0.02 b, respectively, while the measured resonance integrals are 0.55 ± 0.03 b and 0.54 ± 0.04 b, respectively. The present measurements are compared with earlier measurements and evaluations. Presently estimated values confirm the established {sup 139}La(n, γ){sup 140}La cross-sections. The presently measured thermal capture cross-section {sup 140}Ce(n, γ){sup 141}Ce, though lower than the evaluated data, is having higher accuracy compared to previous measurements with large uncertainties. The resonance integral measured is higher (like most previous measurements) than most evaluations requiring a revision of the evaluated data. (orig.)

  11. Measurement of the Neutron Capture Cross Sections of $^{233}$U, $^{237}$Np, $^{240,242}$Pu, $^{241,243}$Am and $^{245}$Cm with a Total Absorption Calorimeter at n_TOF

    CERN Multimedia

    Beer, H; Wiescher, M; Cox, J; Rapp, W; Embid, M; Dababneh, S

    2002-01-01

    Accurate and reliable neutron capture cross section data for actinides are necessary for the poper design, safety regulation and precise performance assessment of transmutation devices such as Fast Critical Reactors or Accelerator Driven Systems (ADS). The goal of this proposal is the measurement of the neutron capture cross sections of $^{233}$U, $^{237}$Np, $^{240,242}$Pu, $^{241,243}$Am and $^{245}$Cm at n_TOF with an accuracy of 5~\\%. $^{233}$U plays an essential role in the Th fuel cycle, which has been proposed as a safer and cleaner alternative to the U fuel cycle. The capture cross sections of $^{237}$Np,$^{240,242}$Pu, $^{241,243}$Am and $^{245}$Cm play a key role in the design and optimization of a strategy for the Nuclear Waste Transmutation. A high accuracy can be achieved at n_TOF in such measurements due to a combination of features unique in the world: high instantaneous neutron fluence and excellent energy resolution of the facility, innovative Data Acquisition System based on flash ADCs and t...

  12. Measurement of the neutron-capture cross section of 76Ge and 74Ge below 15 MeV and its relevance to 0 νββ decay searches of 76Ge

    Science.gov (United States)

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

    2015-02-01

    The neutron radiative-capture cross section of 76Ge was measured between 0.4 and 14.8 MeV using the activation technique. Germanium samples with the isotopic abundance of ∼ 86%76Ge and ∼ 14%74Ge used in the 0 νββ searches by the GERDA and Majorana Collaborations were irradiated with monoenergetic neutrons produced at eleven energies via the 3H (p , n)3He, 2H (d , n)3He and 3H (d , n)4He reactions. Previously, data existed only at thermal energies and at 14 MeV. As a by-product, capture cross-section data were also obtained for 74Ge at neutron energies below 8 MeV. Indium and gold foils were irradiated simultaneously for neutron fluence determination. High-resolution γ-ray spectroscopy was used to determine the γ-ray activity of the daughter nuclei of interest. For the 76Ge total capture cross section the present data are in good agreement with the TENDL-2013 model calculations and the ENDF/B-VII.1 evaluations, while for the 74Ge (n , γ)75Ge reaction, the present data are about a factor of two larger than predicted. It was found that the 74Ge (n , γ)75Ge yield in the High-Purity Germanium (HPGe) detectors used by the GERDA and Majorana Collaborations is only about a factor of two smaller than the 76Ge (n , γ)77Ge yield due to the larger cross section of the former reaction.

  13. Single-level resonance parameters fit nuclear cross-sections

    Science.gov (United States)

    Drawbaugh, D. W.; Gibson, G.; Miller, M.; Page, S. L.

    1970-01-01

    Least squares analyses of experimental differential cross-section data for the U-235 nucleus have yielded single level Breit-Wigner resonance parameters that fit, simultaneously, three nuclear cross sections of capture, fission, and total.

  14. 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.

  15. Calculation and Evaluation of Fission Yields and Capture Cross Sections Leading to the Production of Therapeutic Radionuclide by Means of Nuclear Reactors

    International Nuclear Information System (INIS)

    Sublet, J.C.

    2009-01-01

    Much progress has been made in nuclear medicine that involves the use of radionuclides for both diagnosis and therapy. Because of this qualitative and quantitative growth, the adoption of a set of established radionuclides for various applications, the methods of nuclide production need to be addressed and consideration given to other, emerging radionuclides that are judged to be developing in importance. The methods involved are characterized by the transmutation of isotopes by neutron-induced reactions and decays. Therefore, newly evaluated cross sections, fission yields and decay characteristics of relevance to the reactor production of those therapeutic radionuclides have been reviewed. Considerations of the decay schemes of all the nuclides involved are also included. (author)

  16. Measurements of the neutron capture cross sections and incineration potentials of minor-actinides in high thermal neutron fluxes: Impact on the transmutation of nuclear wastes

    International Nuclear Information System (INIS)

    Bringer, O.

    2007-10-01

    This thesis comes within the framework of minor-actinide nuclear transmutation studies. First of all, we have evaluated the impact of minor actinide nuclear data uncertainties within the cases of 241 Am and 237 Np incineration in three different reactor spectra: EFR (fast), GT-MHR (epithermal) and HI-HWR (thermal). The nuclear parameters which give the highest uncertainties were thus highlighted. As a result of fact, we have tried to reduce data uncertainties, in the thermal energy region, for one part of them through experimental campaigns in the moderated high intensity neutron fluxes of ILL reactor (Grenoble). These measurements were focused onto the incineration and transmutation of the americium-241, the curium-244 and the californium-249 isotopes. Finally, the values of 12 different cross sections and the 241 Am isomeric branching ratio were precisely measured at thermal energy point. (author)

  17. Microscopic cross sections: An utopia?

    Energy Technology Data Exchange (ETDEWEB)

    Hilaire, S. [CEA Bruyeres-le-Chatel, DIF 91 (France); Koning, A.J. [Nuclear Research and Consultancy Group, PO Box 25, 1755 ZG Petten (Netherlands); Goriely, S. [Institut d' Astronomie et d' Astrophysique, Universite Libre de Bruxelles, Campus de la Plaine, CP 226, 1050 Brussels (Belgium)

    2010-07-01

    The increasing need for cross sections far from the valley of stability poses a challenge for nuclear reaction models. So far, predictions of cross sections have relied on more or less phenomenological approaches, depending on parameters adjusted to available experimental data or deduced from systematical relations. While such predictions are expected to be reliable for nuclei not too far from the experimentally known regions, it is clearly preferable to use more fundamental approaches, based on sound physical bases, when dealing with very exotic nuclei. Thanks to the high computer power available today, all major ingredients required to model a nuclear reaction can now be (and have been) microscopically (or semi-microscopically) determined starting from the information provided by a nucleon-nucleon effective interaction. We have implemented all these microscopic ingredients in the TALYS nuclear reaction code, and we are now almost able to perform fully microscopic cross section calculations. The quality of these ingredients and the impact of using them instead of the usually adopted phenomenological parameters will be discussed. (authors)

  18. Microscopic cross sections: An utopia?

    International Nuclear Information System (INIS)

    Hilaire, S.; Koning, A.J.; Goriely, S.

    2010-01-01

    The increasing need for cross sections far from the valley of stability poses a challenge for nuclear reaction models. So far, predictions of cross sections have relied on more or less phenomenological approaches, depending on parameters adjusted to available experimental data or deduced from systematical relations.While such predictions are expected to be reliable for nuclei not too far from the experimentally known regions, it is clearly preferable to use more fundamental approaches, based on sound physical bases, when dealing with very exotic nuclei. Thanks to the high computer power available today, all major ingredients required to model a nuclear reaction can now be (and have been) microscopically (or semi-microscopically) determined starting from the information provided by a nucleon-nucleon effective interaction. We have implemented all these microscopic ingredients in the TALYS nuclear reaction code, and we are now almost able to perform fully microscopic cross section calculations. The quality of these ingredients and the impact of using them instead of the usually adopted phenomenological parameters will be discussed. (authors)

  19. 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.

  20. Absolute measurement of the cross sections of neutron radiative capture for 23Na, Cr, 55Mn, Fe, Ni, 103Rh, Ta, 197Au and 238U in the 10-600keV energy range

    International Nuclear Information System (INIS)

    Le Rigoleur, Claude; Arnaud, Andre; Taste, Jean.

    1976-10-01

    The total energy weighting technique has been applied to measuring absolute neutron capture cross sections for 23 Na, Cr, 55 Mn, Fe, Ni, 103 Rh, Ta, 197 Au, 238 U in the 10-600keV energy range. A non hydrogeneous liquid scintillator was used to detect the gamma from the cascade. The neutron flux was measured with a 10 B INa(Tl) detector or a 6 Li glass scintillator of well known efficiency. The fast time-of-flight technique was used with on line digital computer data processing [fr

  1. CAMAC - supported electronic set-up for the determination of the capture cross section of the reaction 1H(n,d)γ

    International Nuclear Information System (INIS)

    Hutsch, J.; Moeller, K.; Moesner, J.; Neubert, W.; Pilz, W.; Schmidt, G.; Stiehler, T.; Kudin, L.G.; Spiridenkov, E.M.; Volkov, S.S.

    1984-08-01

    After a brief description of the physical problem the experimental apparatus and the electronic set-up for the investigation of the capture reaction 1 H(n,d)γ at E/sub n/ = 25 MeV are described. (author)

  2. Radar cross section

    CERN Document Server

    Knott, Gene; Tuley, Michael

    2004-01-01

    This is the second edition of the first and foremost book on this subject for self-study, training, and course work. Radar cross section (RCS) is a comparison of two radar signal strengths. One is the strength of the radar beam sweeping over a target, the other is the strength of the reflected echo sensed by the receiver. This book shows how the RCS ?gauge? can be predicted for theoretical objects and how it can be measured for real targets. Predicting RCS is not easy, even for simple objects like spheres or cylinders, but this book explains the two ?exact? forms of theory so well that even a

  3. Cross sections of electron loss and capture for beams of O+ in water vapor from the energy range of 0,2 to 1,2 MeV

    International Nuclear Information System (INIS)

    Oliveira, Vitor Jesus de

    2015-01-01

    The study of the interactions between atoms and molecules is important for the knowledge of the cross sections of the processes that contribute to the deposition of energy by charged particle beams used in radiotherapy planning and transport particle simulation codes. Heavy ions, such as oxygen, induce many cellular and molecular damages in human cells.as a result of interaction between the projectile and atoms and molecules. The use of proton and carbon as the projectile interacting with water molecules is well characterized, however there are few studies with oxygen ions. In this work we are interested in the study of electron loss (projectile ionization) and electron capture with charge state 1+. The Pelletron accelerator of 1.7 MeV from the Federal University of Rio de Janeiro housed in the Atomic and Molecular collisions Laboratory (LACAM) has been used, which can accelerate atomic and molecular ions up to speeds of the order of hundredths of light speed, and consists of the source of negative ions, the Wien filter, the accelerator itself and the magnet load selector. The detection device used to evaluate the processes of interaction (capture and loss) between the beam of the O + and the water molecule is a Microchannel Plate (MCP) at the position sensitive anode. The collisions of O + beans are being studied in the range of 0.2 to 1.2 MeV with water vapor (Z = 10). Were obtained the respective absolute cross sections for electron loss and electron capture and compared with the cross sections of the molecule methane (CH4 → Z = 10), the isoelectronic water molecule. The experimental results show an agreement between the measurements with water and methane. Comparisons were made with results of theoretical models for electron loss using the 'Free Collision Model' and for capture the Bohr and Lindhard model. The theoretical results for electron loss show an agreement of experimental data with the model used. The model of Bohr and Lindhard describes

  4. Neutron cross section measurements for the Fast Breeder Program

    International Nuclear Information System (INIS)

    Block, R.C.

    1979-06-01

    This research was concerned with the measurement of neutron cross sections of importance to the Fast Breeder Reactor. The capture and total cross sections of fission products ( 101 102 104 Ru, 143 145 Nd, 149 Sm, 95 97 Mo, Cs, Pr, Pd, 107 Pd, 99 Tc) and tag gases (Kr, 78 80 Kr) were measured up to 100 keV. Filtered neutron beams were used to measure the capture cross section of 238 U (with an Fe filter) and the total cross section of Na (with a Na filter). A radioactive neutron capture detector was developed. A list of publications is included

  5. Within the framework of the new fuel cycle 232Th/233U, determination of the 233Pa(n.γ) radiative capture cross section for neutron energies ranging between 0 and 1 MeV

    International Nuclear Information System (INIS)

    Boyer, S.

    2004-10-01

    The Thorium cycle Th 232 /U 233 may face brilliant perspectives through advanced concepts like molten salt reactors or accelerator driven systems but it lacks accurate nuclear data concerning some nuclei. Pa 233 is one of these nuclei, its high activity makes the direct measurement of its radiative neutron capture cross-section almost impossible. This difficulty has been evaded by considering the transfer reaction Th 232 (He 3 ,p)Pa 234 * in which the Pa 234 nucleus is produced in various excited states according to the amount of energy available in the reaction. The first chapter deals with the thorium cycle and its assets to contribute to the quenching of the fast growing world energy demand. The second chapter gives a detailed description of the experimental setting. A scintillation detector based on deuterated benzene (C 6 D 6 ) has been used to counter gamma ray cascades. The third chapter is dedicated to data analysis. In the last chapter we compare our experimental results with ENDF and JENDL data and with computed values from 2 statistical models in the 0-1 MeV neutron energy range. Our results disagree clearly with evaluated data: our values are always above ENDF and JENDL data but tend to near computed values. We have also perform the measurement of the radiative neutron cross-section of Pa 231 for a 110 keV neutron: σ(n,γ) 2.00 ± 0.14 barn. (A.C.)

  6. Neutron capture cross section measurement of 238U at the n TOF CERN facility with C6D6 scintillation detectors in the energy region from 1 eV to 700 keV

    CERN Document Server

    Mingrone, F.

    2017-01-01

    The aim of this work is to provide a precise and accurate measurement of the 238U(n,g) reaction cross section in the energy region from 1 eV to 700 keV. This reaction is of fundamental importance for the design calculations of nuclear reactors, governing the behaviour of the reactor core. In particular, fast reactors, which are experiencing a growing interest for their ability to burn radioactive waste, operate in the high energy region of the neutron spectrum. In this energy region most recent evaluations disagree due to inconsistencies in the existing measurements of up to 15%. In addition, the assessment of nuclear data uncertainty performed for innovative reactor systems shows that the uncertainty in the radiative capture cross-section of 238U should be further reduced to 1-3% in the energy region from 20 eV to 25 keV. To this purpose, addressed by the Nuclear Energy Agency as a priority nuclear data need, complementary experiments, one at the GELINA and two at the n_TOF facility, were proposed and carrie...

  7. Neutron capture cross section measurement of $^{238}$U at the n_TOF CERN facility in the energy region from 1 eV to 700 keV

    CERN Document Server

    Mingrone, F; Vannini, G; Colonna, N; Gunsing, F; Zugec, P; Altstadt, S; Andrzejewski, J; Audouin, L; Barbagallo, M; Becares, V; Becvavr, F; Belloni, F; Berthoumieux, E; Billowes, J; Bosnar, D; Brugger, M; Calviani, M; Calvino, F; Cano-Ott, D; Carrapico, C; Cerutti, F; Chiaveri, E; Chin, M; Cortes, G; Cortes-Giraldo, M A; Diakaki, M; Domingo-Pardo, C; Duran, I; Dressler, R; Eleftheriadis, C; Ferrari, A; Fraval, K; Ganesan, S; Garcia, A R; Giubrone, G; Goncalves, I F; Gonzalez-Romero, E; Griesmayer, E; Guerrero, C; Hernandez-Prieto, A; Jenkins, D G; Jericha, E; Kadi, Y; Kappeler, F; Karadimos, D; Kivel, N; Koehler, P; Kokkoris, M; Krticka, M; Kroll, J; Lampoudis, C; Langer, C; Leal-Cidoncha, E; Lederer, C; Leeb, H; Leong, L S; Lo Meo, S; Losito, R; Mallick, A; Manousos, A; Marganiec, J; Martinez, T; Mastinu, P F; Mastromarco, M; Mendoza, E; Mengoni, A; Milazzo, P M; Mirea Horia, M; Mondalaers, W; Paradela, C; Pavlik, A; Perkowski, J; Plompen, A; Praena, J; Quesada, J M; Rauscher, T; Reifarth, R; Riego, A; Robles, M S; Rubbia, C; Sabate-Gilarte, M; Sarmento, R; Saxena, A; Schillebeeckx, P; Schmidt, S; Schumann, D; Tagliente, G; LTain, J; Tarrio, D; Tassan-Got, L; Tsinganis, A; Valenta, S; Variale, V; Vaz, P; Ventura, A; Vermeulen, M J; Vlachoudis, V; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiss, C; Wright, T

    2016-01-01

    The aim of this work is to provide a precise and accurate measurement of the $^{238}$U(n,$\\gamma$) reaction cross section in the energy region from 1 eV to 700 keV. This reaction is of fundamental importance for the design calculations of nuclear reactors, governing the behaviour of the reactor core. In particular, fast reactors, which are experiencing a growing interest for their ability to burn radioactive waste, operate in the high energy region of the neutron spectrum. In this energy region most recent evaluations disagree due to inconsistencies in the existing measurements of up to 15%. In addition, the assessment of nuclear data uncertainty performed for innovative reactor systems shows that the uncertainty in the radiative capture cross-section of $^{238}$U should be further reduced to 1-3% in the energy region from 20 eV to 25 keV. To this purpose, addressed by the Nuclear Energy Agency as a priority nuclear data need, complementary experiments, one at the GELINA and two at the n_TOF facility, were pr...

  8. Suitability of a three-dimensional model to measure empathy and its relationship with social and normative adjustment in Spanish adolescents: a cross-sectional study.

    Science.gov (United States)

    Herrera-López, Mauricio; Gómez-Ortiz, Olga; Ortega-Ruiz, Rosario; Jolliffe, Darrick; Romera, Eva M

    2017-09-25

    (1) To examine the psychometric properties of the Basic Empathy Scale (BES) with Spanish adolescents, comparing a two and a three-dimensional structure;(2) To analyse the relationship between the three-dimensional empathy and social and normative adjustment in school. Transversal and ex post facto retrospective study. Confirmatory factorial analysis, multifactorial invariance analysis and structural equations models were used. 747 students (51.3% girls) from Cordoba, Spain, aged 12-17 years (M=13.8; SD=1.21). The original two-dimensional structure was confirmed (cognitive empathy, affective empathy), but a three-dimensional structure showed better psychometric properties, highlighting the good fit found in confirmatory factorial analysis and adequate internal consistent valued, measured with Cronbach's alpha and McDonald's omega. Composite reliability and average variance extracted showed better indices for a three-factor model. The research also showed evidence of measurement invariance across gender. All the factors of the final three-dimensional BES model were direct and significantly associated with social and normative adjustment, being most strongly related to cognitive empathy. This research supports the advances in neuroscience, developmental psychology and psychopathology through a three-dimensional version of the BES, which represents an improvement in the original two-factorial model. The organisation of empathy in three factors benefits the understanding of social and normative adjustment in adolescents, in which emotional disengagement favours adjusted peer relationships. Psychoeducational interventions aimed at improving the quality of social life in schools should target these components of empathy. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  9. Cross sections for atmospheric corrections

    International Nuclear Information System (INIS)

    Meyer, J.P.; Casse, M.; Westergaard, N.

    1975-01-01

    A set of cross sections for spallation of relativistic nuclei is proposed based on (i) the best available proton cross sections, (ii) an extrapolation to heavier nuclei of the dependence on the number of nucleons lost of the 'target factor' observed for C 12 and O 16 by Lindstrom et al. (1975), in analogy with Rudstam's formalism, and (iii) on a normalization of all cross sections to the total cross sections for production of fragments with Asub(f) >= 6. The obtained cross sections for peripheral interactions are not inconsistent with simple geometrical considerations. (orig.) [de

  10. Where's WALY? : A proof of concept study of the 'wellbeing adjusted life year' using secondary analysis of cross-sectional survey data.

    Science.gov (United States)

    Johnson, Rebecca; Jenkinson, David; Stinton, Chris; Taylor-Phillips, Sian; Madan, Jason; Stewart-Brown, Sarah; Clarke, Aileen

    2016-09-08

    The Quality-Adjusted Life Year (QALY) is a measure that combines life extension and health improvement in a single score, reflecting preferences around different types of health gain. It can therefore be used to inform decision-making around allocation of health care resources to mutually exclusive options that would produce qualitatively different health benefits. A number of quality-of-life instruments can be used to calculate QALYs. The EQ-5D is one of the most commonly used, and is the preferred option for submissions to NICE ( https://www.nice.org.uk/process/pmg9/ ). However, it has limitations that might make it unsuitable for use in areas such as public and mental health where interventions may aim to improve well-being. One alternative to the QALY is a Wellbeing-Adjusted Life Year. In this study we explore the need for a Wellbeing-Adjusted Life Year measure by examining the extent to which a measure of wellbeing (the Warwick-Edinburgh Mental Well-being Scale) maps onto the EQ-5D-3L. Secondary analyses were conducted on data from the Coventry Household Survey in which 7469 participants completed the EQ-5D-3L, Warwick-Edinburgh Mental Well-being Scale, and a measure of self-rated health. Data were analysed using descriptive statistics, Pearson's and Spearman's correlations, linear regression, and receiver operating characteristic curves. Approximately 75 % of participants scored the maximum on the EQ-5D-3L. Those with maximum EQ-5D-3L scores reported a wide range of levels of mental wellbeing. Both the Warwick-Edinburgh Mental Well-being Scale and the EQ-5D-3L were able to detect differences between those with higher and lower levels of self-reported health. Linear regression indicated that scores on the Warwick-Edinburgh Mental Well-being Scale and the EQ-5D-3L were weakly, positively correlated (with R(2) being 0.104 for the index and 0.141 for the visual analogue scale). The Warwick-Edinburgh Mental Well-being Scale maps onto the EQ-5D-3L to only a

  11. Variability in prescription drug expenditures explained by adjusted clinical groups (ACG case-mix: A cross-sectional study of patient electronic records in primary care

    Directory of Open Access Journals (Sweden)

    Serrat Josep

    2008-03-01

    Full Text Available Abstract Background In view of rapidly increasing prescription costs, case-mix adjustment should be considered for effective control of costs. We have estimated the variability in pharmacy costs explained by ACG in centers using patient electronic records, profiled centers and physicians and analyzed the correlation between cost and quality of prescription. Methods We analyzed 65,630 patient records attending five primary care centers in Spain during 2005. Variables explored were age, gender, registered diagnosed episodes of care during 2005, total cost of prescriptions, physician and center. One ACG was assigned to each patient with ACG case-mix software version 7.1. In a two-part model, logistic regression was used to explain the incurrence of drug expenditure at the first stage and a linear mixed model that considered the multilevel structure of data modeled the cost, conditional upon incurring any expense. Risk and efficiency indexes in pharmacy cost adjusted for ACG were obtained for centers and physicians. Spearman rank correlation between physician expenditure, adjusted for ACG, and a prescription quality index was also obtained. Pediatric and adult data were analyzed separately. Results No prescription was recorded for 13% of adults and 39.6% of children. The proportion of variance of the incurrence of expenditure explained by ACGs was 0.29 in adults and 0.21 in children. For adults with prescriptions, the variance of cost explained by ACGs was 35.4%, by physician-center was 1.8% and age 10.5% (residual 52.3%. For children, ACGs explained 22.4% of cost and physician-center 10.9% (residual 66.7%. Center efficiency index for adults ranged 0.58 to 1.22 and for children 0.32 to 2.36. Spearman correlation between expenditure and prescription quality index was -0.36 in family physicians (p = 0.019, N = 41 and -0.52 in pediatricians (p = 0.08, N = 12. Conclusion In our setting, ACG is the variable studied that explains more variability in

  12. Measurement of the neutron capture cross section of U{sup 234} in n-TOF at CERN for Generation IV nuclear reactors; Mesure de la section efficace de capture neutronique de l'{sup 234}U a n-TOF au CERN pour les reacteurs nucleaires de generation 4

    Energy Technology Data Exchange (ETDEWEB)

    Dridi, W

    2006-11-15

    Accurate and reliable neutron capture cross sections are needed in many research areas, including stellar nucleosynthesis, advanced nuclear fuel cycles, waste transmutation, and other applied programs. In particular, the accurate knowledge of U{sup 234}(n,{gamma}) reaction cross section is required for the design and realization of nuclear power plants based on the thorium fuel cycle. We have measured the neutron capture cross section of U{sup 234}, with a 4{pi} BaF{sub 2} Total Absorption Calorimeter, at the recently constructed neutron time-of-flight facility n-TOF at CERN in the energy range from 0.03 eV to 1 MeV. Monte-Carlo simulations with GEANT4 and MCNPX of the detector response have been performed. After the background subtraction and correction with dead time and pile-up, the capture yield from 0.03 eV up to 1.5 keV was derived. The analysis of the capture yield in terms of R-matrix resonance parameters is discussed. We have identified 123 resonances and measured the resonance parameters in the energy range from 0.03 eV to 1.5 keV. The mean radiative width <{gamma}{sub {gamma}}> is found to be (38.2 {+-} 1.5) meV and the mean spacing parameter is (11.0 {+-} 0.2) eV, both values agree well with recommended values.

  13. Measurement of the neutron capture cross section of U{sup 234} in n-TOF at CERN for Generation IV nuclear reactors; Mesure de la section efficace de capture neutronique de l'{sup 234}U a n-TOF au CERN pour les reacteurs nucleaires de generation 4

    Energy Technology Data Exchange (ETDEWEB)

    Dridi, W

    2006-11-15

    Accurate and reliable neutron capture cross sections are needed in many research areas, including stellar nucleosynthesis, advanced nuclear fuel cycles, waste transmutation, and other applied programs. In particular, the accurate knowledge of U{sup 234}(n,{gamma}) reaction cross section is required for the design and realization of nuclear power plants based on the thorium fuel cycle. We have measured the neutron capture cross section of U{sup 234}, with a 4{pi} BaF{sub 2} Total Absorption Calorimeter, at the recently constructed neutron time-of-flight facility n-TOF at CERN in the energy range from 0.03 eV to 1 MeV. Monte-Carlo simulations with GEANT4 and MCNPX of the detector response have been performed. After the background subtraction and correction with dead time and pile-up, the capture yield from 0.03 eV up to 1.5 keV was derived. The analysis of the capture yield in terms of R-matrix resonance parameters is discussed. We have identified 123 resonances and measured the resonance parameters in the energy range from 0.03 eV to 1.5 keV. The mean radiative width <{gamma}{sub {gamma}}> is found to be (38.2 {+-} 1.5) meV and the mean spacing parameter is (11.0 {+-} 0.2) eV, both values agree well with recommended values.

  14. XCOM: Photon Cross Sections Database

    Science.gov (United States)

    SRD 8 XCOM: Photon Cross Sections Database (Web, free access)   A web database is provided which can be used to calculate photon cross sections for scattering, photoelectric absorption and pair production, as well as total attenuation coefficients, for any element, compound or mixture (Z <= 100) at energies from 1 keV to 100 GeV.

  15. Doppler broadening of cross sections

    International Nuclear Information System (INIS)

    Buckler, P.A.C.; Pull, I.C.

    1962-12-01

    Expressions for temperature dependent cross-sections in terms of resonance parameters are obtained, involving generalisations of the conventional Doppler functions, ψ and φ. Descriptions of Fortran sub-routines, which calculate broadened cross-sections in accordance with the derived formulae, are included. (author)

  16. Photoneutron cross sections measurements in {sup 9}Be, {sup 13}C e {sup 17}O with thermal neutron capture gamma-rays; Medidas das secoes de choque de fotoneutrons do {sup 9}Be, {sup 13}C e {sup 17}O com radiacao gama de captura de neutrons termicos

    Energy Technology Data Exchange (ETDEWEB)

    Semmler, Renato

    2006-07-01

    Photoneutron cross sections measurements of {sup 9}Be, {sup 13}C and {sup 17}O have been obtained in the energy interval between 1,6 and 10,8 MeV, using neutron capture gamma-rays with high resolution in energy (3 a 21 eV), produced by 21 target materials, placed inside a tangential beam port, near the core of the IPEN/CNEN-SP IEA-R1 (5 MW) research reactor. The samples have been irradiated inside a 4{pi} geometry neutron detector system 'Long Counter', 520,5 cm away from the capture target. The capture gamma-ray flux was determined by means of the analysis of the gamma spectrum obtained by using a Ge(Li) solid-state detector (EG and G ORTEC, 25 cm{sup 3}, 5%), previously calibrated with capture gamma-rays from a standard target of Nitrogen (Melamine). The neutron photoproduction cross section has been measured for each target capture gamma-ray spectrum (compound cross section). A inversion matrix methodology to solve inversion problems for unfolding the set of experimental compound cross sections, was used in order to obtain the cross sections at specific excitation energy values (principal gamma line energies of the capture targets). The cross sections obtained at the energy values of the principal gamma lines were compared with experimental data reported by other authors, with have employed different gamma-ray sources. A good agreement was observed among the experimental data in this work with reported in the literature. (author)

  17. Length bias correction in one-day cross-sectional assessments - The nutritionDay study.

    Science.gov (United States)

    Frantal, Sophie; Pernicka, Elisabeth; Hiesmayr, Michael; Schindler, Karin; Bauer, Peter

    2016-04-01

    A major problem occurring in cross-sectional studies is sampling bias. Length of hospital stay (LOS) differs strongly between patients and causes a length bias as patients with longer LOS are more likely to be included and are therefore overrepresented in this type of study. To adjust for the length bias higher weights are allocated to patients with shorter LOS. We determined the effect of length-bias adjustment in two independent populations. Length-bias correction is applied to the data of the nutritionDay project, a one-day multinational cross-sectional audit capturing data on disease and nutrition of patients admitted to hospital wards with right-censoring after 30 days follow-up. We applied the weighting method for estimating the distribution function of patient baseline variables based on the method of non-parametric maximum likelihood. Results are validated using data from all patients admitted to the General Hospital of Vienna between 2005 and 2009, where the distribution of LOS can be assumed to be known. Additionally, a simplified calculation scheme for estimating the adjusted distribution function of LOS is demonstrated on a small patient example. The crude median (lower quartile; upper quartile) LOS in the cross-sectional sample was 14 (8; 24) and decreased to 7 (4; 12) when adjusted. Hence, adjustment for length bias in cross-sectional studies is essential to get appropriate estimates. Copyright © 2015 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  18. Preliminary study of the α ratio measurement, ratio of the neutron capture cross section to the fission one for 233U, on the PEREN platform. Development and study of the experimental setup

    International Nuclear Information System (INIS)

    Cognet, M.A.

    2007-12-01

    Producing nuclear energy in order to reduce anthropic CO 2 emission and to meet high energy demand, implies three conditions to the nuclear plants of the IV. generation: safety improvements, radioactive waste minimization, and fuel breeding for a sustainable use of the resources. The Thorium fuel cycle used in Molten Salt Reactors seems promising. Many numerical studies based on probabilistic codes are carried out in order to analyse the behaviour of such reactors. Nevertheless, one of the most important parameters is badly known: the alpha ratio of 233 U, ratio of the neutron capture cross section to fission one for 233 U. This key-parameter is necessary to calculate the breeding ratio and thus, the deployment capacities of those reactors. This Ph-D thesis was intended to prepare a precise measurement of the alpha ratio of 233 U between 1 eV and 10 keV. Preliminary measurements have been performed on the experimental platform PEREN. This experimental environment is composed of a lead slowing-down time spectrometer associated with an intense pulsed neutron generator. Capture and fission rates are measured thanks to eight scintillators with their photomultipliers, surrounding a fission chamber. A software analysis sets the coincidence rate between the scintillators. In order to understand perfectly the experimental setup, preliminary tests using a 235 U fission chamber have been done. This experiment resulted in a very low signal to background ratio (1 %). The background coming from the scintillators themselves seriously handicapped the measurement. Another series of experiment has been done with scintillators 5 times thinner. Nevertheless, the signal to background ratio should still be increased to measure the capture of 235 U. To make sure that the experimental setup has totally been understood, we made many comparisons between experimental results and simulations. Two simulation codes were mainly used: MCNP and GEANT4. We paid special attention to quantify the

  19. Polynomial parameterized representation of macroscopic cross section for PWR reactor

    International Nuclear Information System (INIS)

    Fiel, Joao Claudio B.

    2015-01-01

    The purpose of this work is to describe, by means of Tchebychev polynomial, a parameterized representation of the homogenized macroscopic cross section for PWR fuel element as a function of soluble boron concentration, moderator temperature, fuel temperature, moderator density and 235 U 92 enrichment. Analyzed cross sections are: fission, scattering, total, transport, absorption and capture. This parameterization enables a quick and easy determination of the problem-dependent cross-sections to be used in few groups calculations. The methodology presented here will enable to provide cross-sections values to perform PWR core calculations without the need to generate them based on computer code calculations using standard steps. The results obtained by parameterized cross-sections functions, when compared with the cross-section generated by SCALE code calculations, or when compared with K inf , generated by MCNPX code calculations, show a difference of less than 0.7 percent. (author)

  20. Photon-splitting cross sections

    International Nuclear Information System (INIS)

    Johannessen, A.M.; Mork, K.J.; Overbo, I.

    1980-01-01

    The differential cross section for photon splitting (scattering of one photon into two photons) in a Coulomb field, obtained earlier by Shima, has been integrated numerically to yield various differential cross sections. Energy spectra differential with respect to the energy of one of the outgoing photons are presented for several values of the primary photon energy. Selected examples of recoil momentum distributions and some interesting doubly or multiply differential cross sections are also given. Values for the total cross section are obtained essentially for all energies. The screening effect caused by atomic electrons is also taken into account, and is found to be important for high energies, as in e + e - pair production. Comparisons with various approximate results obtained by previous authors mostly show fair agreement. We also discuss the possibilities for experimental detection and find the most promising candidate to be a measurement of both photons, and their energies, at a moderately high energy

  1. NDS multigroup cross section libraries

    International Nuclear Information System (INIS)

    DayDay, N.

    1981-12-01

    A summary description and documentation of the multigroup cross section libraries which exist at the IAEA Nuclear Data Section are given in this report. The libraries listed are available either on tape or in printed form. (author)

  2. Neutron Cross Sections for Aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Forsberg, Leif

    1963-08-15

    Total, elastic, inelastic, (n, 2n), (n, {alpha}), (n, p), and (n, {gamma}) cross sections for aluminium have been compiled from thermal to 100 MeV based upon literature search and theoretical interpolations and estimates. Differential elastic cross sections in the centre of mass system are represented by the Legendre coefficients. This method was chosen in order to obtain the best description of the energy dependence of the anisotropy.

  3. Accurate Cross Sections for Microanalysis

    OpenAIRE

    Rez, Peter

    2002-01-01

    To calculate the intensity of x-ray emission in electron beam microanalysis requires a knowledge of the energy distribution of the electrons in the solid, the energy variation of the ionization cross section of the relevant subshell, the fraction of ionizations events producing x rays of interest and the absorption coefficient of the x rays on the path to the detector. The theoretical predictions and experimental data available for ionization cross sections are limited mainly to K shells of a...

  4. Evaluation for ENDF/B-IV of the neutron cross sections for 235U from 82 eV to 25 keV

    International Nuclear Information System (INIS)

    Peelle, R.W.

    1976-05-01

    Capture and fission cross sections for 235 U in the ''unresolved resonance'' energy region were evaluated to permit determination of local-average resonance parameters for the ENDF/B-IV cross section file. Microscopic data were examined for infinitely dilute average fission and capture cross sections and also for intermediate structure unlikely to be reproduced by statistical fluctuations of resonance widths and spacings within known laws. Evaluated cross sections, averaged over lethargy intervals greater than 0.1, were obtained as an average over selected data sets after appropriate renormalization. Estimated uncertainties are given for these evaluated average cross sections. The ''intermediate'' structure fluctuations common to a few independent data sets were approximated by straight lines joining successive cross sections at 120 selected energy points; the cross sections at the vertices were adjusted to reproduce the evaluated average cross sections over the broad energy regions. Data sources and methods are reviewed, output values are tabulated, and some modified procedures are suggested for future evaluations. Evaluated fission and capture integrals for the resolved resonance region are also tabulated. These are not in agreement with integrals based on the resonance parameters of ENDF/B versions III and IV. 8 tables, 5 figures

  5. Simplified polynomial representation of cross sections for reactor calculation

    International Nuclear Information System (INIS)

    Dias, A.M.; Sakai, M.

    1985-01-01

    It is shown a simplified representation of a cross section library generated by transport theory using the cell model of Wigner-Seitz for typical PWR fuel elements. The effect of burnup evolution through tables of reference cross sections and the effect of the variation of the reactor operation parameters considered by adjusted polynomials are presented. (M.C.K.) [pt

  6. Fusion cross sections from measurements of delayed X-rays

    International Nuclear Information System (INIS)

    Pacheco, A.J.; Gregorio, D.E. di; Fernandez Niello, J.O; Elgue, M.

    1988-01-01

    The program XRAY is a FORTRAN 77 computer code for the extraction of fusion cross sections from delayed X-ray measurements. This is accomplished by calculating the theoretical expressions of the time dependence of the evaporation-residue cross sections and taking them as adjustable parameters in a χ 2 minimization procedure. (orig.)

  7. Measurements and analysis of the {sup 127}I and {sup 129}I neutron capture and total cross sections; Mesure et analyses des sections efficaces neutroniques totales et de capture radiative des iodes 127 et 129 de 0.5 eV a 100keV

    Energy Technology Data Exchange (ETDEWEB)

    Noguere, G

    2005-07-01

    Most of the experimental work on the interaction of neutrons with matter has focused on materials important to reactor physics and reactor structures. By comparison, the corresponding data for minor actinides or long-lived fission products are poor. A significant demand has developed for improved neutron cross-section data of these little-studied nuclides due to the surge of interest in the transmutation of nuclear waste. With 400 kg of {sup 129}I produced yearly in the reactors of the EU countries and a very long {beta}{sup -} half-life of 1.57 x 10{sup 7} years, iodine requires disposal strategies that will isolate this isotope from the environment for long periods of time. Therefore, {sup 129}I is potentially a key long-lived fission product for transmutation applications, since {sup 129}I transmutes in {sup 130}I after a single neutron capture and decays to {sup 130}Xe with a 12.36 h half-life. Accurate capture cross sections would help to reduce uncertainties in waste management concepts. For that purpose, Time-Of-Flight measurements covering the [0.5 eV-100 keV] energy range have been carried out at the 150 MeV pulsed neutron source GELINA of the Institute for Reference Materials and Measurements (IRMM). Two types of experiments have been performed at the IRMM, namely capture and transmission experiments. They are respectively related to the neutron capture and total cross sections. Since the PbI{sub 2} samples used in this work contain natural and radioactive iodine, extensive measurements of {sup 129}I have been carried out under the same experimental conditions as for the {sup 129}I. The data reduction process was performed with the AGS system, and the resonance parameters were extracted with the SAMMY and REFIT shape analysis codes. In a last step, the parameters have been converted into ENDF-6 format and processed with the NJOY code to produce point-wise and multigroup cross sections, as well as MCNP and ERANOS libraries. (author)

  8. Test of RIPL-2 cross section calculations

    International Nuclear Information System (INIS)

    Herman, M.

    2002-01-01

    The new levels and optical segments and microscopic HF-BCS level densities (part of the density segment) were tested in practical calculations of cross sections for neutron induced reactions on 22 targets (40-Ca, 47-Ti, 52-Cr, 55-Mn, 58-Ni, 63-Cu, 71-Ga, 80-Se, 92-Mo, 93-Nb, 100-Mo, 109-Ag, 114-Cd, 124-Sn, 127-I, 133-Cs, 140-Ce, 153-Eu, 169-Tm, 186-W, 197-Au, 208-Pb). For each target all reactions involving up to 3 neutron, 1 proton and 1 α-particle emissions (subject to actual reaction thresholds) were considered in the incident energy range from 1 keV up to 20 MeV (in some cases up to 27 MeV). In addition, total, elastic, and neutron capture cross sections were calculated

  9. NSLINK, Coupling of NJOY Cross-Sections Generator Code to SCALE-3 System

    International Nuclear Information System (INIS)

    De Leege, P.F.A

    1991-01-01

    1 - Description of program or function: NSLINK (NJOY - SCALE - LINK) is a set of computer codes to couple the NJOY cross-section generation code to the SCALE-3 code system (using AMPX-2 master library format) retaining the Nordheim resolved resonance treatment option. 2 - Method of solution: The following module and codes are included in NSLINK: XLACSR: This module is a stripped-down version of the XLACS-2 code. The module passes all l=0 resonance parameters as well as the contribution from all other resonances to the group cross-sections, the contribution from the wings of the l=0 resonances, the background cross-section and possible interference for multilevel Breit-Wigner resonance parameters. The group cross-sections are stored in the appropriate 1-D cross-section arrays. The output file has AMPX-2 master format. The original NJOY code is used to calculate all other data. The XLACSR module is included in the NJOY code. MILER: This code converts NJOY output (GENDF format) to AMPX-2 master format. The code is an extensively revised version of the original MILER code. In addition, the treatment of thermal scattering matrices at different temperatures is included. UNITABR: This code is a revised version of the UNITAB code. It merges the output of XLACSR and MILER in such a way that contributions from the bodies of the l=0 resonances in the resolved energy range, calculated by XLACSR, are subtracted from the 1-D group cross-section arrays for fission (MT=18) and neutron capture (MT=102). The l=0 resonance parameters and the contributions from the bodies of these resonances are added separately (MT=1023, 1022 and 1021). The total cross-section (MT=1), the absorption cross- section (MT=27) and the neutron removal cross-section (MT=101) values are adjusted. In the case of Bondarenko data, infinite dilution values of the cross-sections (MT=1, 18 and 102) are changed in the same way as the 1-D cross-section. The output file of UNITABR is in AMPX-2 master format and

  10. Low Energy Neutrino Cross Sections

    International Nuclear Information System (INIS)

    Zeller, G.P.

    2004-01-01

    Present atmospheric and accelerator based neutrino oscillation experiments operate at low neutrino energies (Ev ∼ 1 GeV) to access the relevant regions of oscillation parameter space. As such, they require precise knowledge of the cross sections for neutrino-nucleon interactions in the sub-to-few GeV range. At these energies, neutrinos predominantly interact via quasi-elastic (QE) or single pion production processes, which historically have not been as well studied as the deep inelastic scattering reactions that dominate at higher energies.Data on low energy neutrino cross sections come mainly from bubble chamber, spark chamber, and emulsion experiments that collected their data decades ago. Despite relatively poor statistics and large neutrino flux uncertainties, these measurements provide an important and necessary constraint on Monte Carlo models in present use. The following sections discuss the current status of QE, resonant single pion, coherent pion, and single kaon production cross section measurements at low energy

  11. Terahertz radar cross section measurements

    DEFF Research Database (Denmark)

    Iwaszczuk, Krzysztof; Heiselberg, Henning; Jepsen, Peter Uhd

    2010-01-01

    We perform angle- and frequency-resolved radar cross section (RCS) measurements on objects at terahertz frequencies. Our RCS measurements are performed on a scale model aircraft of size 5-10 cm in polar and azimuthal configurations, and correspond closely to RCS measurements with conventional radar...

  12. Pion-nucleus cross sections

    International Nuclear Information System (INIS)

    Barashenkov, V.S.

    1990-01-01

    The tables of inelastic and total cross sections of π ± mesons interactions with nuclei 4 He- 238 U are presented. The tables are obtained by theoretical analysis of known experimental data for energies higher some tens of MeV. 1 ref.; 1 tab

  13. Measurement of actinide neutron cross sections

    International Nuclear Information System (INIS)

    Firestone, Richard B.; Nitsche, Heino; Leung, Ka-Ngo; Perry, DaleL.; English, Gerald

    2003-01-01

    The maintenance of strong scientific expertise is critical to the U.S. nuclear attribution community. It is particularly important to train students in actinide chemistry and physics. Neutron cross-section data are vital components to strategies for detecting explosives and fissile materials, and these measurements require expertise in chemical separations, actinide target preparation, nuclear spectroscopy, and analytical chemistry. At the University of California, Berkeley and the Lawrence Berkeley National Laboratory we have trained students in actinide chemistry for many years. LBNL is a leader in nuclear data and has published the Table of Isotopes for over 60 years. Recently, LBNL led an international collaboration to measure thermal neutron capture radiative cross sections and prepared the Evaluated Gamma-ray Activation File (EGAF) in collaboration with the IAEA. This file of 35, 000 prompt and delayed gamma ray cross-sections for all elements from Z=1-92 is essential for the neutron interrogation of nuclear materials. LBNL has also developed new, high flux neutron generators and recently opened a 1010 n/s D+D neutron generator experimental facility

  14. Measurement of 241Am Ground State Radiative Neutron Capture Cross Section with Cold Neutron Beam. Progress Report on Research Contract HUN14318 for the CRP on Minor Actinide Neutron Reaction Data (MANREAD)

    International Nuclear Information System (INIS)

    Belgya, T.; Szentmiklosi, L.; Kis, Z.; Nagy, N.M.; Konya, J.

    2012-01-01

    The ground state cross section of 242 Am has been measured with beams of cold neutrons at the Budapest Research Reactor using the X-ray emission of the decay product of 242 Pu. This methodology avoids the uncertainty caused by resonance neutrons in the pile activations. The target was characterized with gamma and X-ray spectrometry. The obtained ground state cross section is 540 ± 32 b, which is at the low end of the most recent literature values, but agrees with most of them within their uncertainty. (author)

  15. Neutron cross sections for fusion

    International Nuclear Information System (INIS)

    Haight, R.C.

    1979-10-01

    First generation fusion reactors will most likely be based on the 3 H(d,n) 4 He reaction, which produces 14-MeV neutrons. In these reactors, both the number of neutrons and the average neutron energy will be significantly higher than for fission reactors of the same power. Accurate neutron cross section data are therefore of great importance. They are needed in present conceptual designs to calculate neutron transport, energy deposition, nuclear transmutation including tritium breeding and activation, and radiation damage. They are also needed for the interpretation of radiation damage experiments, some of which use neutrons up to 40 MeV. In addition, certain diagnostic measurements of plasma experiments require nuclear cross sections. The quality of currently available data for these applications will be reviewed and current experimental programs will be outlined. The utility of nuclear models to provide these data also will be discussed. 65 references

  16. Differential cross sections for neutrino scattering on 12C

    International Nuclear Information System (INIS)

    Kolbe, E.

    1996-01-01

    Differential cross sections for neutrino scattering on 12 C are calculated within the (continuum) random phase approximation model. The charged current (ν e ,e - ) and (ν μ ,μ - ) capture reactions on 12 C are measured by the LSND Collaboration at LAMPF. We investigate and discuss the merits of such studies, especially the information that can be extracted from data for differential neutrino scattering cross sections. copyright 1996 The American Physical Society

  17. Low energy total cross section of 36Ar

    International Nuclear Information System (INIS)

    Mughabghab, S.F.; Magurno, B.A.

    1975-01-01

    To compare the predictions of the valence model with measured partial radiative widths of 36 Ar an accurate knowledge of the bound-level parameters is required. This is achieved by carrying out a Breit-Wigner parameter fit to the total cross section of 36 Ar measured by Chrien et al and renormalized to the recommended values of the thermal capture and scattering cross sections. (1 figure, 1 table) (U.S.)

  18. Negative ion detachment cross sections

    International Nuclear Information System (INIS)

    Champion, R.L.; Doverspike, L.D.

    1992-10-01

    The authors have measured absolute cross sections for electron detachment and charge exchange for collision of O and S with atomic hydrogen, have investigated the sputtering and photodesorption of negative ions from gas covered surfaces, and have begun an investigation of photon-induced field emission of electrons from exotic structures. Brief descriptions of these activities as well as future plans for these projects are given below

  19. Wind Turbine Radar Cross Section

    Directory of Open Access Journals (Sweden)

    David Jenn

    2012-01-01

    Full Text Available The radar cross section (RCS of a wind turbine is a figure of merit for assessing its effect on the performance of electronic systems. In this paper, the fundamental equations for estimating the wind turbine clutter signal in radar and communication systems are presented. Methods of RCS prediction are summarized, citing their advantages and disadvantages. Bistatic and monostatic RCS patterns for two wind turbine configurations, a horizontal axis three-blade design and a vertical axis helical design, are shown. The unique electromagnetic scattering features, the effect of materials, and methods of mitigating wind turbine clutter are also discussed.

  20. Progress on FP13 Total Cross Section Measurements Capability

    Energy Technology Data Exchange (ETDEWEB)

    Ullmann, John Leonard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Couture, Aaron Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Koehler, Paul E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mocko, Michal [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mosby, Shea Morgan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wender, Stephen Arthur [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-26

    An accurate knowledge of the neutron capture cross section is important for many applications. Experimental measurements are important since theoretical calculations of capture have been notoriously difficult, with the ratio of measured to calculated cross sections often a factor of 2 or more in the 10 keV to 1 MeV region. However, a direct measurement of capture cannot be made on many interesting radioactive nuclides because of their short half-life or backgrounds caused by their nuclear decay. On the other hand, neutron transmission measurements of the total cross section are feasible for a wide range of radioactive nuclides since the detectors are far from the sample, and often are less sensitive to decay radiation. The parameters extracted from a total cross section measurement, which include the average resonance spacing, the neutron strength function, and the average total radiation width, (Γγ), provide tight constraints on the calculation of the capture cross section, and when applied produce much more accurate results. These measurements can be made using the intense epithermal neutron flux at the Lujan Center on relatively small quantities of target material. It was the purpose of this project to investigate and develop the capability to make these measurements. A great deal of progress was made towards establishing this capability during 2016, including setting up the flight path and obtaining preliminary results, but more work remains to be done.

  1. Parameterized representation of macroscopic cross section for PWR reactor

    International Nuclear Information System (INIS)

    Fiel, João Cláudio Batista; Carvalho da Silva, Fernando; Senra Martinez, Aquilino; Leal, Luiz C.

    2015-01-01

    Highlights: • This work describes a parameterized representation of the homogenized macroscopic cross section for PWR reactor. • Parameterization enables a quick determination of problem-dependent cross-sections to be used in few group calculations. • This work allows generating group cross-section data to perform PWR core calculations without computer code calculations. - Abstract: The purpose of this work is to describe, by means of Chebyshev polynomials, a parameterized representation of the homogenized macroscopic cross section for PWR fuel element as a function of soluble boron concentration, moderator temperature, fuel temperature, moderator density and 235 92 U enrichment. The cross-section data analyzed are fission, scattering, total, transport, absorption and capture. The parameterization enables a quick and easy determination of problem-dependent cross-sections to be used in few group calculations. The methodology presented in this paper will allow generation of group cross-section data from stored polynomials to perform PWR core calculations without the need to generate them based on computer code calculations using standard steps. The results obtained by the proposed methodology when compared with results from the SCALE code calculations show very good agreement

  2. K+ nucleus total cross sections

    International Nuclear Information System (INIS)

    Sawafta, R.

    1990-01-01

    The scattering of K + mesons from nuclei has attracted considerable interest in the last few years. The K + holds a very special position as the weakest of all strongly interaction probes. The average cross section is not larger than about 10 mb at lab momenta below 800 MeV/c, corresponding to a mean free path in the nucleus larger than 5 fm. Thus the K + is capable of probing the entire volume of the nucleus. Single scattering of the K + with a nucleon in the nucleus dominates the nuclear scattering, and only small and calculable higher order corrections are needed. The nucleon is a dynamical entity and its internal structure can, in principle, be altered by its surrounding nuclear environment. This work reports an experiment in which the K + is used to compare the nucleon in the nucleus with a free nucleon

  3. Terahertz radar cross section measurements.

    Science.gov (United States)

    Iwaszczuk, Krzysztof; Heiselberg, Henning; Jepsen, Peter Uhd

    2010-12-06

    We perform angle- and frequency-resolved radar cross section (RCS) measurements on objects at terahertz frequencies. Our RCS measurements are performed on a scale model aircraft of size 5-10 cm in polar and azimuthal configurations, and correspond closely to RCS measurements with conventional radar on full-size objects. The measurements are performed in a terahertz time-domain system with freely propagating terahertz pulses generated by tilted pulse front excitation of lithium niobate crystals and measured with sub-picosecond time resolution. The application of a time domain system provides ranging information and also allows for identification of scattering points such as weaponry attached to the aircraft. The shapes of the models and positions of reflecting parts are retrieved by the filtered back projection algorithm.

  4. [Fast neutron cross section measurements

    International Nuclear Information System (INIS)

    1991-01-01

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

  5. Neutron cross sections: Book of curves

    International Nuclear Information System (INIS)

    McLane, V.; Dunford, C.L.; Rose, P.F.

    1988-01-01

    Neuton Cross Sections: Book of Curves represents the fourth edition of what was previously known as BNL-325, Neutron Cross Sections, Volume 2, CURVES. Data is presented only for (i.e., intergrated) reaction cross sections (and related fission parameters) as a function of incident-neutron energy for the energy range 0.01 eV to 200 MeV. For the first time, isometric state production cross sections have been included. 11 refs., 4 figs

  6. Nuclear Forensics and Radiochemistry: Cross Sections

    Energy Technology Data Exchange (ETDEWEB)

    Rundberg, Robert S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-11-08

    The neutron activation of components in a nuclear device can provide useful signatures of weapon design or sophistication. This lecture will cover some of the basics of neutron reaction cross sections. Nuclear reactor cross sections will also be presented to illustrate the complexity of convolving neutron energy spectra with nuclear excitation functions to calculate useful effective reactor cross sections. Deficiencies in the nuclear database will be discussed along with tools available at Los Alamos to provide new neutron cross section data.

  7. JENDL gas-production cross section file

    International Nuclear Information System (INIS)

    Nakagawa, Tsuneo; Narita, Tsutomu

    1992-05-01

    The JENDL gas-production cross section file was compiled by taking cross-section data from JENDL-3 and by using the ENDF-5 format. The data were given to 23 nuclei or elements in light nuclei and structural materials. Graphs of the cross sections and brief description on their evaluation methods are given in this report. (author)

  8. Integral nucleus-nucleus cross sections

    International Nuclear Information System (INIS)

    Barashenkov, V.S.; Kumawat, H.

    2003-01-01

    Expressions approximating the experimental integral cross sections for elastic and inelastic interactions of light and heavy nuclei at the energies up to several GeV/nucleon are presented. The calculated cross sections are inside the corridor of experimental errors or very close to it. Described in detail FORTRAN code and a numerical example of the cross section approximation are also presented

  9. Cross-Sectional Analysis of Longitudinal Mediation Processes.

    Science.gov (United States)

    O'Laughlin, Kristine D; Martin, Monica J; Ferrer, Emilio

    2018-01-01

    Statistical mediation analysis can help to identify and explain the mechanisms behind psychological processes. Examining a set of variables for mediation effects is a ubiquitous process in the social sciences literature; however, despite evidence suggesting that cross-sectional data can misrepresent the mediation of longitudinal processes, cross-sectional analyses continue to be used in this manner. Alternative longitudinal mediation models, including those rooted in a structural equation modeling framework (cross-lagged panel, latent growth curve, and latent difference score models) are currently available and may provide a better representation of mediation processes for longitudinal data. The purpose of this paper is twofold: first, we provide a comparison of cross-sectional and longitudinal mediation models; second, we advocate using models to evaluate mediation effects that capture the temporal sequence of the process under study. Two separate empirical examples are presented to illustrate differences in the conclusions drawn from cross-sectional and longitudinal mediation analyses. Findings from these examples yielded substantial differences in interpretations between the cross-sectional and longitudinal mediation models considered here. Based on these observations, researchers should use caution when attempting to use cross-sectional data in place of longitudinal data for mediation analyses.

  10. Market skewness risk and the cross section of stock returns

    NARCIS (Netherlands)

    Chang, B.; Christoffersen, P.; Jacobs, K.

    2013-01-01

    The cross section of stock returns has substantial exposure to risk captured by higher moments of market returns. We estimate these moments from daily Standard & Poor's 500 index option data. The resulting time series of factors are genuinely conditional and forward-looking. Stocks with high

  11. Measurements of neutron cross sections of radioactive waste nuclides

    Energy Technology Data Exchange (ETDEWEB)

    Katoh, Toshio [Gifu College of Medical Technology, Seki, Gifu (Japan); Harada, Hideo; Nakamura, Shoji; Tanase, Masakazu; Hatsukawa, Yuichi

    1998-01-01

    Accurate nuclear reaction cross sections of radioactive fission products and transuranic elements are required for research on nuclear transmutation methods in nuclear waste management. Important fission products in the nuclear waste management are {sup 137}Cs, {sup 135}Cs, {sup 90}Sr, {sup 99}Tc and {sup 129}I because of their large fission yields and long half-lives. The present authors have measured the neutron capture cross sections and resonance integrals of {sup 137}Cs, {sup 90}Sr and {sup 99}Tc. The purpose of this study is to measure the neutron capture cross sections and resonance integrals of nuclides, {sup 129}I and {sup 135}Cs accurately. Preliminary experiments were performed by using Rikkyo University Reactor and JRR-3 reactor at Japan Atomic Energy Research Institute (JAERI). Then, it was decided to measure the cross section and resonance integral of {sup 135}Cs by using the JRR-3 Reactor because this measurement required a high flux reactor. On the other hand, those of {sup 129}I were measured at the Rikkyo Reactor because the product nuclides, {sup 130}I and {sup 130m}I, have short half-lives and this reactor is suitable for the study of short lived nuclide. In this report, the measurements of the cross section and resonance integral of {sup 135}Cs are described. To obtain reliable values of the cross section and resonance integral of {sup 135}Cs(n, {gamma}){sup 136}Cs reaction, a quadrupole mass spectrometer was used for the mass analysis of nuclide in the sample. A progress report on the cross section of {sup 134}Cs, a neighbour of {sup 135}Cs, is included in this report. A report on {sup 129}I will be presented in the Report on the Joint-Use of Rikkyo University Reactor. (author)

  12. [Fast neutron cross section measurements

    International Nuclear Information System (INIS)

    Knoll, G.F.

    1992-01-01

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

  13. Relativistic photon-Maxwellian electron cross sections

    International Nuclear Information System (INIS)

    Wienke, B.R.; Lathrop, B.L.; Devaney, J.J.

    1986-01-01

    Temperature corrected cross sections, complementing the Klein-Nishina set, are developed for astrophysical, plasma, and transport applications. The set is obtained from a nonlinear least squares fit to the exact photon-Maxwellian electron cross sections, using the static formula as the asymptotic basis. Two parameters are sufficient (two decimal places) to fit the exact cross sections over a range of 0-100 keV in electron temperature, and 0-1 MeV in incident photon energy. The fit is made to the total cross sections, yet the parameters predict both total and differential scattering cross sections well. Corresponding differential energy cross sections are less accurate. An extended fit to (just) the total cross sections, over the temperature and energy range 0-5 MeV, is also described. (author)

  14. CASTHY, Statistical Model for Neutron Cross-Sections and Gamma-Ray Spectra

    International Nuclear Information System (INIS)

    Igarasi, Sin-iti; Fukahori, Tokio

    1998-01-01

    Description of program or function: CASTHY calculates neutron cross sections of total, shape elastic scattering and compound nucleus formation with the optical model, and compound elastic, inelastic and capture cross sections by the statistical model. The other cross sections, such as (n,2n), (n,p), (n,f) reactions are treated as cross sections of competing processes, and their sum is given through input data. Capture gamma-ray spectra can also be calculated. The branching ratio for primary transition can be treated in a particular way, if required

  15. Evaluation of the neutron cross sections of 235U in the thermal energy region. Final report

    International Nuclear Information System (INIS)

    Leonard, B.R. Jr.; Kottwitz, D.A.; Thompson, J.K.

    1976-02-01

    The objective of this work has been to improve the knowledge of the thermal cross sections of the fissile nuclei as a step toward providing a standard data base for the nuclear industry. The methodology uses a form of the Adler-Adler multilevel-fission theory and Breit-Wigner multilevel-scattering theory. It incorporates these theories in a general nonlinear least-squares (LSQ) fitting program SIGLEARNThe analysis methodology in this work was applied to the thermal data on 235 U. A reference data file has been developed which includes most of the known data of interest. The first important result of this work is the assessment of the shape uncertainties of the partial cross sections. The results of our studies lead to the following values and error estimates for 235 U g factors in a thermal (20.44 0 C) energy spectrum: g/sub f/ = 0.97751 (+-0.11%); g/sub γ/ = 0.98230 (+-0.14%). A second important result of this study is the development of a recommended set of 2200 m/s (0.0253 eV) values of the parameters and the probable range of further adjustment which might be made. The analysis also provides the result of a common interpretation of energy-dependent absolute cross-section data of different measurements to yield a consistent set of experimental 0.0253 eV values with rigorous error estimates. It also provides normalization factors for relative fission and capture cross sections on a common basis with rigorous error estimates. The results of these analyses provide a basis for deciding what new measurements would be most beneficial. The most important of these would be improved direct capture data in the thermal region

  16. NEUTRON CROSS SECTION EVALUATIONS OF FISSION PRODUCTS BELOW THE FAST ENERGY REGION

    International Nuclear Information System (INIS)

    OH, S.Y.; CHANG, J.; MUGHABGHAB, S.

    2000-01-01

    Neutron cross section evaluations of the fission-product isotopes, 95 Mo, 99 Tc, 101 Ru, 103 Rh, 105 Pd, 109 Ag, 131 Xe, 133 Cs, 141 Pr, 141 Nd, 147 Sm, 149 Sm, 150 Sm, 151 Sm, 152 Sm, 153 Eu, 155 Gd, and 157 Gd were carried out below the fast neutron energy region within the framework of the BNL-KAERI international collaboration. In the thermal energy region, the energy dependence of the various cross-sections was calculated by applying the multi-level Breit-Wigner formalism. In particular, the strong energy dependence of the coherent scattering lengths of 155 Gd and 157 Gd were determined and were compared with recent calculations of Lynn and Seeger. In the resonance region, the recommended resonance parameters, reported in the BNL compilation, were updated by considering resonance parameter information published in the literature since 1981. The s-wave and, if available, p-wave reduced neutron widths were analyzed in terms of the Porter-Thomas distribution to determine the average level spacings and the neutron strength functions. Average radiative widths were also calculated from measured values of resolved energy resonances. The average resonance parameters determined in this study were compared with those in the BNL and other compilations, as well as the ENDF/B-VI, JEF-2.2, and JENDL-3.2 data libraries. The unresolved capture cross sections of these isotopes, computed with the determined average resonance parameters, were compared with measurements, as well as the ENDF/B-VI evaluations. To achieve agreement with the measurements, in a few cases minor adjustments in the average resonance parameters were made. Because of astrophysical interest, the Maxwellian capture cross sections of these nuclides at a neutron temperature of 30 keV were computed and were compared with other compilations and evaluations

  17. NEUTRON CROSS SECTION EVALUATIONS OF FISSION PRODUCTS BELOW THE FAST ENERGY REGION

    Energy Technology Data Exchange (ETDEWEB)

    OH,S.Y.; CHANG,J.; MUGHABGHAB,S.

    2000-05-11

    Neutron cross section evaluations of the fission-product isotopes, {sup 95}Mo, {sup 99}Tc, {sup 101}Ru, {sup 103}Rh, {sup 105}Pd, {sup 109}Ag, {sup 131}Xe, {sup 133}Cs, {sup 141}Pr, {sup 141}Nd, {sup 147}Sm, {sup 149}Sm, {sup 150}Sm, {sup 151}Sm, {sup 152}Sm, {sup 153}Eu, {sup 155}Gd, and {sup 157}Gd were carried out below the fast neutron energy region within the framework of the BNL-KAERI international collaboration. In the thermal energy region, the energy dependence of the various cross-sections was calculated by applying the multi-level Breit-Wigner formalism. In particular, the strong energy dependence of the coherent scattering lengths of {sup 155}Gd and {sup 157}Gd were determined and were compared with recent calculations of Lynn and Seeger. In the resonance region, the recommended resonance parameters, reported in the BNL compilation, were updated by considering resonance parameter information published in the literature since 1981. The s-wave and, if available, p-wave reduced neutron widths were analyzed in terms of the Porter-Thomas distribution to determine the average level spacings and the neutron strength functions. Average radiative widths were also calculated from measured values of resolved energy resonances. The average resonance parameters determined in this study were compared with those in the BNL and other compilations, as well as the ENDF/B-VI, JEF-2.2, and JENDL-3.2 data libraries. The unresolved capture cross sections of these isotopes, computed with the determined average resonance parameters, were compared with measurements, as well as the ENDF/B-VI evaluations. To achieve agreement with the measurements, in a few cases minor adjustments in the average resonance parameters were made. Because of astrophysical interest, the Maxwellian capture cross sections of these nuclides at a neutron temperature of 30 keV were computed and were compared with other compilations and evaluations.

  18. Background-cross-section-dependent subgroup parameters

    International Nuclear Information System (INIS)

    Yamamoto, Toshihisa

    2003-01-01

    A new set of subgroup parameters was derived that can reproduce the self-shielded cross section against a wide range of background cross sections. The subgroup parameters are expressed with a rational equation which numerator and denominator are expressed as the expansion series of background cross section, so that the background cross section dependence is exactly taken into account in the parameters. The advantage of the new subgroup parameters is that they can reproduce the self-shielded effect not only by group basis but also by subgroup basis. Then an adaptive method is also proposed which uses fitting procedure to evaluate the background-cross-section-dependence of the parameters. One of the simple fitting formula was able to reproduce the self-shielded subgroup cross section by less than 1% error from the precise evaluation. (author)

  19. Scattering cross section for various potential systems

    Directory of Open Access Journals (Sweden)

    Myagmarjav Odsuren

    2017-08-01

    Full Text Available We discuss the problems of scattering in this framework, and show that the applied method is very useful in the investigation of the effect of the resonance in the observed scattering cross sections. In this study, not only the scattering cross sections but also the decomposition of the scattering cross sections was computed for the α–α system. To obtain the decomposition of scattering cross sections into resonance and residual continuum terms, the complex scaled orthogonality condition model and the extended completeness relation are used. Applying the present method to the α–α and α–n systems, we obtained good reproduction of the observed phase shifts and cross sections. The decomposition into resonance and continuum terms makes clear that resonance contributions are dominant but continuum terms and their interference are not negligible. To understand the behavior of observed phase shifts and the shape of the cross sections, both resonance and continuum terms are calculated.

  20. Scattering cross section for various potential systems

    Energy Technology Data Exchange (ETDEWEB)

    Odsuren, Myagmarjav; Khuukhenkhuu, Gonchigdorj; Davaa, Suren [Nuclear Research Center, School of Engineering and Applied Sciences, National University of Mongolia, Ulaanbaatar (Mongolia); Kato, Kiyoshi [Nuclear Reaction Data Centre, Faculty of Science, Hokkaido University, Sapporo (Japan)

    2017-08-15

    We discuss the problems of scattering in this framework, and show that the applied method is very useful in the investigation of the effect of the resonance in the observed scattering cross sections. In this study, not only the scattering cross sections but also the decomposition of the scattering cross sections was computed for the α–α system. To obtain the decomposition of scattering cross sections into resonance and residual continuum terms, the complex scaled orthogonality condition model and the extended completeness relation are used. Applying the present method to the α–α and α–n systems, we obtained good reproduction of the observed phase shifts and cross sections. The decomposition into resonance and continuum terms makes clear that resonance contributions are dominant but continuum terms and their interference are not negligible. To understand the behavior of observed phase shifts and the shape of the cross sections, both resonance and continuum terms are calculated.

  1. Scattering and absorption differential cross sections for double ...

    Indian Academy of Sciences (India)

    degraded gamma quanta at the same time as the recoil electron. ... [2–4] are confined to energy, angular distribution, collision differential cross section and ... The positions of the two detectors are adjusted in such a way that they do not ... the energy values weighted in proportion to the probability for occurrence of this ...

  2. Cross-section methodology in SIMMER

    International Nuclear Information System (INIS)

    Soran, P.D.

    1975-11-01

    The cross-section methodology incorporated in the SIMMER code is described. Data base for all cross sections is the ENDF/B system with various progressing computer codes to group collapse and modify the group constants which are used in SIMMER. Either infinitely dilute cross sections or the Bondarenko formalism can be used in SIMMER. Presently only a microscopic treatment is considered, but preliminary macroscopic algorithms have been investigated

  3. Cross-section methodology in SIMMER

    International Nuclear Information System (INIS)

    Soran, P.D.

    1976-05-01

    The cross-section methodology incorporated in the SIMMER code is described. Data base for all cross sections is the ENDF/B system with various progressing computer codes to group collapse and modify the group constants which are used in SIMMER. Either infinitely dilute cross sections or the Bondarenko formalism can be used in SIMMER. Presently only a microscopic treatment is considered, but preliminary macroscopic algorithms have been investigated

  4. High ET jet cross sections at CDF

    International Nuclear Information System (INIS)

    Flaugher, B.

    1996-08-01

    The inclusive jet cross section for p anti p collisions at √s = 1.8 TeV as measured by the CDF collaboration will be presented. Preliminary CDF measurements of the Σ E T cross section at √s = 1.8 TeV and the central inclusive jet cross section at √s = 0.630 TeV will also be shown

  5. Recommended activation detector cross sections (RNDL-82)

    International Nuclear Information System (INIS)

    Bondars, Kh.Ya.; Lapenas, A.A.

    1984-01-01

    The results of the comparison between measured and calculated average cross sections in 5 benchmark experiments are presented. Calculations have been based on the data from 10 libraries of evaluated cross sections. The recommended library (RNDL-82) of the activation detector cross sections has been created on the basis of the comparison. RNDL-82, including 26 reactions, and the basic characteristics of the detectors are presented. (author)

  6. Total neutron cross section of lead

    International Nuclear Information System (INIS)

    Kanda, K.; Aizawa, O.

    1976-01-01

    The total thermal-neutron cross section of natural lead under various physical conditions was measured by the transmission method. It became clear that the total cross section at room temperature previously reported is lower than the present data. The total cross section at 400, 500, and 600 0 C, above the melting point of lead, 327 0 C, was also measured, and the changes in the cross section as a function of temperature were examined, especially near and below the melting point. The data obtained for the randomly oriented polycrystalline state at room temperature were in reasonable agreement with the theoretical values calculated by the THRUSH and UNCLE-TOM codes

  7. Modelling interaction cross sections for intermediate and low energy ions

    International Nuclear Information System (INIS)

    Toburen, L.H.; Shinpaugh, J.L.; Justiniano, E.L.B.

    2002-01-01

    When charged particles slow in tissue they undergo electron capture and loss processes than can have profound effects on subsequent interaction cross sections. Although a large amount of data exists for the interaction of bare charged particles with atoms and molecules, few experiments have been reported for these 'dressed' particles. Projectile electrons contribute to an impact-parameter-dependent screening of the projectile charge that precludes straightforward scaling of energy loss cross sections from those of bare charged particles. The objective of this work is to develop an analytical model for the energy-loss-dependent effects of screening on differential ionisation cross sections that can be used in track structure calculations for high LET ions. As a first step a model of differential ionisation cross sections for bare ions has been combined with a simple screening model to explore cross sections for intermediate and low energy dressed ions in collisions with atomic and molecular gas targets. The model is described briefly and preliminary results compared to measured electron energy spectra. (author)

  8. Electron collision cross sections of mercury

    International Nuclear Information System (INIS)

    Suzuki, Susumu; Kuzuma, Kiyotaka; Itoh, Haruo

    2006-01-01

    In this paper, we propose a new collision cross section set for mercury which revises the original set summarized by Hayashi in 1989. Hanne reported three excitation collision cross sections (6 3 P 0 , 6 3 P 1 , 6 3 P 2 ) determined from an electron beam experiment in 1988. As a matter for regret, no attentive consideration was given to combining these three excitation cross sections with the cross section set of Hayashi. Therefore we propose a new set where these three excitation cross sections are included. In this study, other two excitation cross sections (6 1 P 1 , 6 3 D 3 ) except for the three excitation collision cross sections (6 3 P 0 , 6 3 P 1 , 6 3 P 2 ) are taken from the original set of Hayashi. The momentum transfer cross section and the ionization collision cross section are also taken from Hayashi. A Monte Carlo Simulation (MCS) technique is applied for evaluating our new cross section set. The present results of the electron drift velocity and the ionization coefficient are compared to experimental values. Agreement is secured in relation to the electron drift velocity for 1.5 Td 2 ) is the reduced electric field, E (V/cm) is the electric field, N (1/cm 3 ) is the number density of mercury atoms at 0degC, 1 Torr, E/N is also equal to 2.828 x 10 -17 E/p 0 from the relation of the ideal gas equation, p 0 (Torr) is gas pressure at 0degC, 1 Torr=1.33322 x 10 -2 N/cm -2 and 10 -17 V/cm 2 is called 1 Td. Thus it is ensured that our new cross section set is reasonable enough to be used up to 100 eV when considering with the electron drift velocity and the ionization coefficient. (author)

  9. Neutron cross section measurement using the Oak Ridge Electron Linear Accelerator

    International Nuclear Information System (INIS)

    Winters, R.R.

    1991-08-01

    This report discusses: argon-40 -- neutron reaction total cross sections from 6.9 kev to 50 kev; The maxwellian averaged neutron capture cross section of oxygen-16; r-matrix parameter analysis of the lead-208 -- neutron reaction cross section measurement; r-matrix parameter analysis of the ORELA neutron transmission zirconium-90 low energy measurement; porting computer codes from the HP9000 to the IBM RISC/6000;and measurements of neutron reactions with strontium-88, zirconium-90, and calcium-40

  10. Neutron cross section measurements at ORELA

    International Nuclear Information System (INIS)

    Dabbs, J.W.T.

    1979-01-01

    ORELA (Oak Ridge Electron Linear Accelerator) has been for the last decade the most powerful and useful pulsed neutron time-of-flight facility in the world, particularly in the broad midrange of neutron energies (10 eV to 1 MeV). This position will be enhanced with the addition of a pulse narrowing prebuncher, recently installed and now under test. Neutron capture, fission, scattering, and total cross sections are measured by members of the Physics and Engineering Physics Divisions of ORNL, and by numerous guests and visitors. Several fundamental and applied measurements are described, with some emphasis on instrumentation used. The facility comprises the accelerator and its target(s), 10 evacuated neutron flight paths having 18 measurement stations at flight path distances 8.9 to 200 meters, and a complex 4-computer data acquisition system capable of handling some 17,000 32-bit events/s from a total of 12 data input ports. The system provides a total of 2.08 x 10 6 words of data storage on 3 fast disk units. In addition, a dedicated PDP-10 timesharing system with a 250-megabyte disk system and 4 PDP-15 graphic display satellites permits on-site data reduction and analysis. More than 10 man-years of application software development supports the system, which is used directly by individual experiments. 12 figures, 1 table

  11. First measurement of the Rayleigh cross section

    NARCIS (Netherlands)

    Naus, H.; Ubachs, W.

    2000-01-01

    Rayleigh cross section for N2, Ar and SF6 was performed using the technique of cavity ring-down spectroscopy (CRDS). The experiment was based on the assumption that scattering cross section is equal to the extinction in the absence of absorption. The theory explains the molecular origin of

  12. Total cross section of highly excited strings

    International Nuclear Information System (INIS)

    Lizzi, F.; Senda, I.

    1990-01-01

    The unpolarized total cross section for the joining of two highly excited strings is calculated. The calculation is performed by taking the average overall states in the given excitation levels of the initial strings. We find that the total cross section grows with the energy and momentum of the initial states. (author). 8 refs, 1 fig

  13. Compilation of cross-sections. Pt. 1

    International Nuclear Information System (INIS)

    Flaminio, V.; Moorhead, W.G.; Morrison, D.R.O.; Rivoire, N.

    1983-01-01

    A compilation of integral cross-sections for hadronic reactions is presented. This is an updated version of CERN/HERA 79-1, 79-2, 79-3. It contains all data published up to the beginning of 1982, but some more recent data have also been included. Plots of the cross-sections versus incident laboratory momentum are also given. (orig.)

  14. Total cross section results for deuterium electrodisintegration

    International Nuclear Information System (INIS)

    Skopik, D.M.; Murphy, J.J. II; Shin, Y.M.

    1976-01-01

    Theoretical total cross sections for deuterium electrodisintegration are presented as a function of incident electron energy. The cross section has been calculated using virtual photon theory with Partovi's photodisintegration calculation for E/subx/ > 10 MeV and effective range theory for E/subx/ 2 H(e, n) reaction in Tokamak reactors

  15. Model cross section calculations using LAHET

    International Nuclear Information System (INIS)

    Prael, R.E.

    1992-01-01

    The current status of LAHET is discussed. The effect of a multistage preequilibrium exciton model following the INC is examined for neutron emission benchmark calculations, as is the use of a Fermi breakup model for light nuclei rather than an evaporation model. Comparisons are made also for recent fission cross section experiments, and a discussion of helium production cross sections is presented

  16. Vibrational enhancement of total breakup cross sections

    International Nuclear Information System (INIS)

    Haftel, M.I.; Lim, T.K.

    1984-01-01

    This paper considers the role of multi-two-body bound states, namely vibrational excitations, on total three-body breakup cross-sections. Total cross-sections are usually easy to measure, and they play a fundamental role in chemical kinetics. (orig.)

  17. Interference analysis of fission cross section

    International Nuclear Information System (INIS)

    Toshkov, S.A.; Yaneva, N.B.

    1976-01-01

    The formula for the reaction cross-section based on the R-matrix formalism considering the interference between the two neighbouring resonances, referred to the same value of total momentum was used for the analysis of the cross-section of resonance neutron induced fission of 230Pu. The experimental resolution and thermal motion of the target nuclei were accounted for numerical integration

  18. Compilation of cross-sections. Pt. 4

    International Nuclear Information System (INIS)

    Alekhin, S.I.; Ezhela, V.V.; Lugovsky, S.B.; Tolstenkov, A.N.; Yushchenko, O.P.; Baldini, A.; Cobal, M.; Flaminio, V.; Capiluppi, P.; Giacomelli, G.; Mandrioli, G.; Rossi, A.M.; Serra, P.; Moorhead, W.G.; Morrison, D.R.O.; Rivoire, N.

    1987-01-01

    This is the fourth volume in our series of data compilations on integrated cross-sections for weak, electromagnetic, and strong interaction processes. This volume covers data on reactions induced by photons, neutrinos, hyperons, and K L 0 . It contains all data published up to June 1986. Plots of the cross-sections versus incident laboratory momentum are also given. (orig.)

  19. Recommended evaluation procedure for photonuclear cross section

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young-Ouk; Chang, Jonghwa; Fukahori, Tokio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    In order to generate photonuclear cross section library for the necessary applications, data evaluation is combined with theoretical evaluation, since photonuclear cross sections measured cannot provide all necessary data. This report recommends a procedure consisting of four steps: (1) analysis of experimental data, (2) data evaluation, (3) theoretical evaluation and, if necessary, (4) modification of results. In the stage of analysis, data obtained by different measurements are reprocessed through the analysis of their discrepancies to a representative data set. In the data evaluation, photonuclear absorption cross sections are evaluated via giant dipole resonance and quasi-deutron mechanism. With photoabsorption cross sections from the data evaluation, theoretical evaluation is applied to determine various decay channel cross sections and emission spectra using equilibrium and preequilibrium mechanism. After this, the calculated results are compared with measured data, and in some cases the results are modified to better describe measurements. (author)

  20. Comparative analysis among several cross section sets

    International Nuclear Information System (INIS)

    Caldeira, A.D.

    1983-01-01

    Critical parameters were calculated using the one dimensional multigroup transport theory for several cross section sets. Calculations have been performed for water mixtures of uranium metal, plutonium metal and uranium-thorium oxide, and for metallics systems, to determine the critical dimensions of geometries (sphere and cylinder). For this aim, the following cross section sets were employed: 1) multigroup cross section sets obtained from the GAMTEC-II code; 2) the HANSEN-ROACH cross section sets; 3) cross section sets from the ENDF/B-IV, processed by the NJOY code. Finally, we have also calculated the corresponding critical radius using the one dimensional multigroup transport DTF-IV code. The numerical results agree within a few percent with the critical values obtained in the literature (where the greatest discrepancy occured in the critical dimensions of water mixtures calculated with the values generated by the NJOY code), a very good results in comparison with similar works. (Author) [pt

  1. Activation cross section data file, (1)

    International Nuclear Information System (INIS)

    Yamamuro, Nobuhiro; Iijima, Shungo.

    1989-09-01

    To evaluate the radioisotope productions due to the neutron irradiation in fission of fusion reactors, the data for the activation cross sections ought to be provided. It is planning to file more than 2000 activation cross sections at final. In the current year, the neutron cross sections for 14 elements from Ni to W have been calculated and evaluated in the energy range 10 -5 to 20 MeV. The calculations with a simplified-input nuclear cross section calculation system SINCROS were described, and another method of evaluation which is consistent with the JENDL-3 were also mentioned. The results of cross section calculation are in good agreement with experimental data and they were stored in the file 8, 9 and 10 of ENDF/B format. (author)

  2. Bonderenko self-shielded cross sections and multiband parameters derived from the LLL Evaluated-Nuclear-Data Library (ENDL)

    International Nuclear Information System (INIS)

    Cullen, D.E.

    1978-01-01

    Bonderenko self-shielded cross sections and multiband parameters from the Lawrence Livermore Laboratory Evaluated-Nuclear-Data Library (ENDL) as of July 4, 1978 are presented. These data include total, elastic, capture, and fission cross sections in the TART 175 group structure. Multiband parameters are listed. Bonderenko self-shielded cross section and the multiband parameters are presented on microfiche

  3. Is the quasielastic pion cross section really bigger than the pion-nucleus reaction cross section

    International Nuclear Information System (INIS)

    Silbar, R.R.

    1979-01-01

    It is shown that soft pion charge exchanges may increase the inclusive (π + ,π 0 ') cross section, relative to the total quasielastic (π + ,π + ') cross section, by as much as a factor of two. 4 references

  4. Female medical leadership: cross sectional study.

    Science.gov (United States)

    Kvaerner, K J; Aasland, O G; Botten, G S

    1999-01-09

    To assess the relation between male and female medical leadership. Cross sectional study on predictive factors for female medical leadership with data on sex, age, specialty, and occupational status of Norwegian physicians. Oslo, Norway. 13 844 non-retired Norwegian physicians. Medical leaders, defined as physicians holding a leading position in hospital medicine, public health, academic medicine, or private health care. 14.6% (95% confidence interval 14.0% to 15.4%) of the men were leaders compared with 5.1% (4.4% to 5.9%) of the women. Adjusted for age men had a higher estimated probability of leadership in all categories of age and job, the highest being in academic medicine with 0.57 (0.42 to 0.72) for men aged over 54 years compared with 0.39 (0.21 to 0.63) for women in the same category. Among female hospital physicians there was a positive relation between the proportion of women in their specialty and the probability of leadership. Women do not reach senior positions as easily as men. Medical specialties with high proportions of women have more female leaders.

  5. The Cross-Section of Expected Stock Returns.

    OpenAIRE

    Fama, Eugene F; French, Kenneth R

    1992-01-01

    Two easily measured variables, size and book-to-market equity, combine to capture the cross-sectional variation in average stock returns associated with market "beta", size, leverage, book-to-market equity, and earnings-price ratios. Moreover, when the tests allow for variation in "beta" that is unrelated to size, t he relation between market "beta" and average return is flat, even when "beta" is the only explanatory variable. Copyright 1992 by American Finance Association.

  6. Nuclear Astrophysics and Neutron Cross Section Measurements Using the ORELA

    Energy Technology Data Exchange (ETDEWEB)

    Winters, R. R.

    2000-08-25

    This is the final report for a research program which has been continuously supported by the AEC, ERDA, or USDOE since 1973. The neutron total and capture cross sections for n + {sup 88}Sr have been measured over the neutron energy range 100 eV to 1 MeV. The report briefly summaries our results and the importance of this work for nucleosynthesis and the optical model.

  7. Hauser*5, a computer code to calculate nuclear cross sections

    International Nuclear Information System (INIS)

    Mann, F.M.

    1979-07-01

    HAUSER*5 is a computer code that uses the statistical (Hauser-Feshbach) model, the pre-equilibrium model, and a statistical model of direct reactions to predict nuclear cross sections. The code is unrestricted as to particle type, includes fission and capture, makes width-fluctuation corrections, and performs three-body calculations - all in minimum computer time. Transmission coefficients can be generated internally or supplied externally. This report describes equations used, necessary input, and resulting output. 2 figures, 4 tables

  8. Nuclear Astrophysics and Neutron Cross Section Measurements Using the ORELA

    International Nuclear Information System (INIS)

    Winters, R. R.

    2000-01-01

    This is the final report for a research program which has been continuously supported by the AEC, ERDA, or USDOE since 1973. The neutron total and capture cross sections for n + 88 Sr have been measured over the neutron energy range 100 eV to 1 MeV. The report briefly summaries our results and the importance of this work for nucleosynthesis and the optical model

  9. Electron-impact cross sections of Ne

    International Nuclear Information System (INIS)

    Tsurubuchi, S.; Arakawa, K.; Kinokuni, S.; Motohashi, K.

    2000-01-01

    Electron-impact absolute emission cross sections were measured for the 3p→3s transitions of Ne. Excitation functions of the 3s→2p first resonance lines were measured in the energy range from the threshold to 1000 eV by a polarization-free optical method and relative cross sections were normalized to the absolute values, (41.0±5.4)x10 -19 cm 2 for the 73.6 nm line and (7.1±1.0)x10 -19 cm 2 for the 74.4 nm line, which were determined at 500 eV. The integrated level-excitation cross sections of Suzuki et al for the 1s 2 and 1s 4 levels were combined with the corresponding 3p→3s cascade cross sections obtained in this paper to give absolute emission cross sections for the resonance lines. The level-excitation cross sections of the 1s 2 and 1s 4 states in Paschen notation were determined from the threshold to 1000 eV by subtracting 3p→3s cascade cross sections from the corresponding 3s→2p emission cross sections of the resonance lines. A large cascade contribution is found in the emission cross section of the resonance lines. It is 28.5% for the 73.6 nm line and 49.6% for the 74.4 nm line at 40 eV, and 17.0 and 61.8%, respectively, at 300 eV. (author)

  10. Recent progress in fast neutron activation cross section data

    International Nuclear Information System (INIS)

    Michaelis, W.

    A brief review is given of some significant investigations performed during the past few years in the area of fast neutron activation cross sections that may be relevant for the use of nuclear techniques in the exploration of mineral resources, in process and quality control in industry as well as for general analytical purposes. Differential capture cross sections are considered for the natural elements or isotopes of Fe, Cu, Se, Y, Nb, Cd, In, Gd, W, Os and Au. Some of the data are compared with statistical model calculations. Experimental and evaluated average cross sections for capture and threshold reactions in the spontaneous fission neutron field of 252 Cf are reviewed taking into account the elements or isotopes of Mg, Al, Si, S, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Sr, Zr, Nb, Cd, In, Ba, Ta and Au. A summary of recent studies of differential cross sections for threshold reactions comprises data on Al, Si, S, Ti, Fe, Co, Ni, Cu, Zn, Zr, Nb, Ta, W and Au. Besides experimental investigations, evaluations and theoretical model calculations are considered. Cross sections at 14 MeV and in the region around this energy are reviewed for Na, Mg, Al, Cl, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Br, Sr, Zr, Nb, In, Er, Yb, Ta, W, Os, Ir, Au and Pb. Particular emphasis is laid on (n,p), (n,2n) and (n,α) reactions. (n,n') reactions are allowed for if the half-life of the metastable state excited permits elemental analyses by common experimental techniques. (orig.)

  11. Cross-sectional anatomy for computed tomography

    International Nuclear Information System (INIS)

    Farkas, M.L.

    1988-01-01

    This self-study guide recognizes that evaluation and interpretation of CT-images demands a firm understanding of both cross-sectional anatomy and the principles of computed tomography. The objectives of this book are: to discuss the basic principles of CT, to stress the importance of cross-sectional anatomy to CT through study of selected cardinal transverse sections of head, neck, and trunk, to explain orientation and interpretation of CT-images with the aid of corresponding cross-sectional preparations

  12. NNLO jet cross sections by subtraction

    International Nuclear Information System (INIS)

    Somogyi, G.; Bolzoni, P.; Trocsanyi, Z.

    2010-06-01

    We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of an earlier NNLO subtraction scheme over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state. (orig.)

  13. Differential Top Cross-section Measurements

    CERN Document Server

    Fenton, Michael James; The ATLAS collaboration

    2017-01-01

    The top quark is the heaviest known fundamental particle. The measurement of the differential top-quark pair production cross-section provides a stringent test of advanced perturbative QCD calculations. The ATLAS collaboration has performed detailed measurements of those differential cross sections at a centre-of-mass energy of 13 TeV. This talk focuses on differential cross-section measurements in the lepton+jets final state, including using boosted top quarks to probe our understanding of top quark production in the TeV regime.

  14. Hardon cross sections at ultra high energies

    International Nuclear Information System (INIS)

    Yodh, G.B.

    1987-01-01

    A review of results on total hadronic cross sections at ultra high energies obtained from a study of longitudinal development of cosmic ray air showers is given. The experimental observations show that proton-air inelastic cross section increases from 275 mb to over 500 mb as the collision energy in the center of mass increases from 20 GeV to 20 TeV. The proton-air inelastic cross section, obtained from cosmic ray data at √s = 30 TeV, is compared with calculations using various different models for the energy variation of the parameters of the elementary proton-proton interaction. Three conclusions are derived

  15. NNLO jet cross sections by subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Somogyi, G.; Bolzoni, P. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Trocsanyi, Z. [CERN, Geneva (Switzerland)

    2010-06-15

    We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of an earlier NNLO subtraction scheme over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state. (orig.)

  16. NNLO jet cross sections by subtraction

    CERN Document Server

    Somogyi, Gabor; Trocsanyi, Zoltan

    2010-01-01

    We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of the NNLO subtraction scheme of [1-4], over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state.

  17. Measurements of Neutron Induced Cross Sections at the Oak Ridge Electron Linear Accelerator

    International Nuclear Information System (INIS)

    Guber, K.H.; Harvey, J.A.; Hill, N.W.; Koehler, P.E.; Leal, L.C.; Sayer, R.O.; Spencer, R.R.

    1999-01-01

    We have used the Oak Ridge Electron Linear Accelerator (ORELA) to measure neutron total and the fission cross sections of 233 U in the energy range from 0.36 eV to 700 keV. We report average fission and total cross sections. Also, we measured the neutron total cross sections of 27 Al and Natural chlorine as well as the capture cross section of Al over an energy range from 100 eV up to about 400 keV

  18. Measurement of the 243Am capture cross section at the n{sub T}OF facility; Medida de la sección eficaz de captura del 243Am en la instalación n{sub T}OF

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza Cembranos, E.

    2014-07-01

    Nuclear data for minor actinides are necessary for improving the design and performance of advanced reactors and transmutation devices for the incineration of radioactive nuclear waste [Sal08, Gon09, Ali04, Ali06]. In particular, the 243Am isotope is relevant since it is the minor actinide which contributes more to the radiotoxicity of the nuclear waste between s3 03 and s3 04 years. In addition, the neutron capture in 243Am is the main gate to the creation of 244Cm and higher mass isotopes. The purpose of the this work is to provide experimental data on the 243Am(n, ) for improving the current evaluations. At present, there is no published neutron capture measurement of 243Am below 250 eV, and all the existing evaluations of the elastic and capture cross sections are based essentially on a single transmission measurement [Sim74]. Above 250 eV there are only a few capture measurements available [Wes85, Wis83], which show discrepancies that make them incompatible. Due to the lack of experimental data on 243Am the standard ENDF-6 format libraries present sizeable di rences between each other...(Author)

  19. Calculation of the resonance cross section functions

    International Nuclear Information System (INIS)

    Slipicevic, K.F.

    1967-11-01

    This paper includes the procedure for calculating the Doppler broadened line shape functions ψ and χ which are needed for calculation of resonance cross section functions. The obtained values are given in tables

  20. Fission cross section measurements at intermediate energies

    International Nuclear Information System (INIS)

    Laptev, Alexander

    2005-01-01

    The activity in intermediate energy particle induced fission cross-section measurements of Pu, U isotopes, minor actinides and sub-actinides in PNPI of Russia is reviewed. The neutron-induced fission cross-section measurements are under way in the wide energy range of incident neutrons from 0.5 MeV to 200 MeV at the GNEIS facility. In number of experiments at the GNEIS facility, the neutron-induced fission cross sections were obtained for many nuclei. In another group of experiments the proton-induced fission cross-section have been measured for proton energies ranging from 200 to 1000 MeV at 100 MeV intervals using the proton beam of PNPI synchrocyclotron. (author)

  1. Measurement of multinucleon transfer cross-sections

    Indian Academy of Sciences (India)

    Keywords. Ni(C, ), Fe(C, ), =C, C, B, B, Be, Be, Be, Be, Li, Li; = 60 MeV; measured reaction cross-section; elastic scattering angular distribution; deduced transfer probabilities and enhancement factors.

  2. Calculation of the resonance cross section functions

    Energy Technology Data Exchange (ETDEWEB)

    Slipicevic, K F [Institute of nuclear sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

    1967-11-15

    This paper includes the procedure for calculating the Doppler broadened line shape functions {psi} and {chi} which are needed for calculation of resonance cross section functions. The obtained values are given in tables.

  3. Pion-nucleus cross sections approximation

    International Nuclear Information System (INIS)

    Barashenkov, V.S.; Polanski, A.; Sosnin, A.N.

    1990-01-01

    Analytical approximation of pion-nucleus elastic and inelastic interaction cross-section is suggested, with could be applied in the energy range exceeding several dozens of MeV for nuclei heavier than beryllium. 3 refs.; 4 tabs

  4. Status of neutron dosimetry cross sections

    International Nuclear Information System (INIS)

    Griffin, P.J.; Kelly, J.G.

    1992-01-01

    Several new cross section libraries, such as ENDF/B-VI(release 2), IRDF-90,JEF-2.2, and JENDL-3 Dosimetry, have recently been made available to the dosimetry community. the Sandia National Laboratories (SNL) Radiation Metrology Laboratory (RML) has worked with these libraries since pre-release versions were available. this paper summarizes the results of the intercomparison and testing of dosimetry cross sections. As a result of this analysis, a compendium of the best dosimetry cross sections was assembled from the available libraries for use within the SNL RML. this library, referred to as the SNLRML Library, contains 66 general dosimetry sensors and 3 special dosimeters unique to the RML sensor inventory. The SNLRML cross sections have been put into a format compatible with commonly used spectrum determination codes

  5. Tachyonic ionization cross sections of hydrogenic systems

    Energy Technology Data Exchange (ETDEWEB)

    Tomaschitz, Roman [Department of Physics, Hiroshima University, 1-3-1 Kagami-yama, Higashi-Hiroshima 739-8526 (Japan)

    2005-03-11

    Transition rates for induced and spontaneous tachyon radiation in hydrogenic systems as well as the transversal and longitudinal ionization cross sections are derived. We investigate the interaction of the superluminal radiation field with matter in atomic bound-bound and bound-free transitions. Estimates are given for Ly-{alpha} transitions effected by superluminal quanta in hydrogen-like ions. The tachyonic photoelectric effect is scrutinized, in the Born approximation and at the ionization threshold. The angular maxima occur at different scattering angles in the transversal and longitudinal cross sections, which can be used to sift out longitudinal tachyonic quanta in a photon flux. We calculate the tachyonic ionization and recombination cross sections for Rydberg states and study their asymptotic scaling with respect to the principal quantum number. At the ionization threshold of highly excited states of order n {approx} 10{sup 4}, the longitudinal cross section starts to compete with photoionization, in recombination even at lower levels.

  6. a cross-sectional analytic study 2014

    African Journals Online (AJOL)

    Assessment of HIV/AIDS comprehensive correct knowledge among Sudanese university: a cross-sectional analytic study 2014. ... There are limited studies on this topic in Sudan. In this study we investigated the Comprehensive correct ...

  7. Methods for calculating anisotropic transfer cross sections

    International Nuclear Information System (INIS)

    Cai, Shaohui; Zhang, Yixin.

    1985-01-01

    The Legendre moments of the group transfer cross section, which are widely used in the numerical solution of the transport calculation can be efficiently and accurately constructed from low-order (K = 1--2) successive partial range moments. This is convenient for the generation of group constants. In addition, a technique to obtain group-angle correlation transfer cross section without Legendre expansion is presented. (author)

  8. Heisenberg rise of total cross sections

    International Nuclear Information System (INIS)

    Ezhela, V.V.; Yushchenko, O.P.

    1988-01-01

    It is shown that on the basis of the original idea of Heisenberg on the quasiclassical picture of extended particle interactions one can construct a satisfactory description of the total cross sections, elastic cross sections, elastic diffractive slopes and mean charged multiplicities in the cm energy range from 5 to 900 GeV, and produce reasonable extrapolations up to several tens of TeV. 14 refs.; 7 figs.; 2 tabs

  9. Evaluation methods for neutron cross section standards

    International Nuclear Information System (INIS)

    Bhat, M.R.

    1980-01-01

    Methods used to evaluate the neutron cross section standards are reviewed and their relative merits, assessed. These include phase-shift analysis, R-matrix fit, and a number of other methods by Poenitz, Bhat, Kon'shin and the Bayesian or generalized least-squares procedures. The problems involved in adopting these methods for future cross section standards evaluations are considered, and the prospects for their use, discussed. 115 references, 5 figures, 3 tables

  10. Extracting integrated and differential cross sections in low energy heavy-ion reactions from backscattering measurements

    Energy Technology Data Exchange (ETDEWEB)

    Sargsyan, V. V. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Yerevan State University, 0025 Yerevan (Armenia); Adamian, G. G., E-mail: adamian@theor.jinr.ru [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Antonenko, N. V. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Mathematical Physics Department, Tomsk Polytechnic University, 634050 Tomsk (Russian Federation); Diaz-Torres, A. [European Centre for Theoretical Studies in Nuclear Physics and Related Areas, I-38123 Villazzano, Trento (Italy); Gomes, P. R. S. [de Fisica, Universidade Federal Fluminense, Av. Litorânea, s/n, Niterói, R.J. 24210-340 (Brazil); Lenske, H. [Institut für Theoretische Physik der Justus–Liebig–Universität, D–35392 Giessen (Germany)

    2016-07-07

    We suggest new methods to extract elastic (quasi-elastic) scattering angular distribution and reaction (capture) cross sections from the experimental elastic (quasi-elastic) backscattering excitation function taken at a single angle.

  11. Formulating analytic expressions for atomic collision cross sections

    International Nuclear Information System (INIS)

    Tabata, Tatsuo; Kubo, Hirotaka; Sataka, Masao

    2003-08-01

    Methods to formulate analytic expression for atomic collision cross sections as a function of projectile energy are described on the basis of the experiences of the data compilation work for more than 20 years. Topics considered are the choice of appropriate functional forms for the expressions and optimization of adjustable parameters. To make extrapolation possible, functions to be used should have the form with reasonable asymptotic behavior. In this respect, modified Green-McNeal formulas have been found useful for various atomic collision cross sections. For ionization processes, a modified Lotz formula has often given a good fit. The ALESQ code for least-squares fits has been convenient to optimize adjustable parameters in analytic expressions. (author)

  12. Reconstruction of point cross-section from ENDF data file for Monte Carlo applications

    International Nuclear Information System (INIS)

    Kumawat, H.; Saxena, A.; Carminati, F.; )

    2016-12-01

    Monte Carlo neutron transport codes are one of the best tools to simulate complex systems like fission and fusion reactors, Accelerator Driven Sub-critical systems, radio-activity management of spent fuel and waste, optimization and characterization of neutron detectors, optimization of Boron Neutron Capture Therapy, imaging etc. The neutron cross-section and secondary particle emission properties are the main input parameters of such codes. The fission, capture and elastic scattering cross-sections have complex resonating structures. Evaluated Nuclear Data File (ENDF) contains these cross-sections and secondary parameters. We report the development of reconstruction procedure to generate point cross-sections and probabilities from ENDF data file. The cross-sections are compared with the values obtained from PREPRO and in some cases NJOY codes. The results are in good agreement. (author)

  13. Differential cross sections in a thick brane world scenario

    Science.gov (United States)

    Pedraza, Omar; Arceo, R.; López, L. A.; Cerón, V. E.

    2018-04-01

    The elastic differential cross section is calculated at low energies for the elements He and Ne using an effective 4D electromagnetic potential coming from the contribution of the massive Kaluza-Klein modes of the 5D vector field in a thick brane scenario. The length scale is adjusted in the potential to compare with known experimental data and to set bounds for the parameter of the model.

  14. Charge changing collision cross sections of atomic ions

    International Nuclear Information System (INIS)

    Bliman, S.; Dousson, S.; Geller, R.; Jacquot, B.; Van Houtte, D.

    1980-05-01

    A device has been built to measure charge changing cross sections of atomic ions. It consists of an E.C.R. ion source (Micromafios) that delivers oxygen ions up to charge + 8, argon ions up to charge + 13. The ion source potential may be varied from 1 up to 10 kVolts. A first magnet is used to charge analyze the extracted beam. For a given charge state, the ion beam is passed in a collision cell whose pressure may be varied. The ions undergoing collisions on the target are analyzed by a second magnet and collected. The single collision condition is checked. Different collisions are considered: 1- Charge exchange collisions of argon ions with charge 2<=Z<=12 on argon. Cross sections for capture of 1, 2 and 3 electrons are given. 2- Stripping of argon ions (1<=Z<=4) on argon atoms. 3- Charge exchange of oxygen ions (2<=Z<=8) colliding on deuterium. One and two electron capture cross sections are presented

  15. A Pebble Bed Reactor cross section methodology

    International Nuclear Information System (INIS)

    Hudson, Nathanael H.; Ougouag, Abderrafi M.; Rahnema, Farzad; Gougar, Hans

    2009-01-01

    A method is presented for the evaluation of microscopic cross sections for the Pebble Bed Reactor (PBR) neutron diffusion computational models during convergence to an equilibrium (asymptotic) fuel cycle. This method considers the isotopics within a core spectral zone and the leakages from such a zone as they arise during reactor operation. The randomness of the spatial distribution of fuel grains within the fuel pebbles and that of the fuel and moderator pebbles within the core, the double heterogeneity of the fuel, and the indeterminate burnup of the spectral zones all pose a unique challenge for the computation of the local microscopic cross sections. As prior knowledge of the equilibrium composition and leakage is not available, it is necessary to repeatedly re-compute the group constants with updated zone information. A method is presented to account for local spectral zone composition and leakage effects without resorting to frequent spectrum code calls. Fine group data are pre-computed for a range of isotopic states. Microscopic cross sections and zone nuclide number densities are used to construct fine group macroscopic cross sections, which, together with fission spectra, flux modulation factors, and zone buckling, are used in the solution of the slowing down balance to generate a new or updated spectrum. The microscopic cross-sections are then re-collapsed with the new spectrum for the local spectral zone. This technique is named the Spectral History Correction (SHC) method. It is found that this method accurately recalculates local broad group microscopic cross sections. Significant improvement in the core eigenvalue, flux, and power peaking factor is observed when the local cross sections are corrected for the effects of the spectral zone composition and leakage in two-dimensional PBR test problems.

  16. Electron attachment cross sections obtained from electron attachment spectroscopy

    International Nuclear Information System (INIS)

    Popp, P.; Baumbach, J.I.; Leonhardt, J.W.; Mothes, S.

    1988-01-01

    Electron capture detectors have a high sensitivity for substances with high thermal electron attachment cross sections. The electron attachment spectroscopy makes it possible to change the mean electron energy in such a way that the maximum for dissociative electron attachment is reached. Thus, best operation modes of the detection system as well as significant dependencies of electron attachment coefficients are available. Cross sections for electron attachment as a function of the electron energy are obtained with the knowledge of electron energy distribution functions from Boltzmann equation analysis by a special computer code. A disadvantage of this electron attachment spectroscopy is the superposition of space charge effects due to the decrease of the electron drift velocity with increasing mean electron energy. These influences are discussed. (author)

  17. Top quark production cross-section measurements

    CERN Document Server

    Chen, Ye; The ATLAS collaboration

    2017-01-01

    Measurements of the inclusive and differential cross-sections for top-quark pair and single top production cross sections in proton-proton collisions with the ATLAS detector at the Large Hadron Collider are presented at center-of-mass energies of 8 TeV and 13 TeV. The inclusive measurements reach high precision and are compared to the best available theoretical calculations. These measurements, including results using boosted tops, probe our understanding of top-pair production in the TeV regime. The results are compared to Monte Carlo generators implementing LO and NLO matrix elements matched with parton showers and NLO QCD calculations. For the t-channel single top measurement, the single top-quark and anti-top-quark total production cross-sections, their ratio, as well as differential cross sections are also presented. A measurement of the production cross-section of a single top quark in association with a W boson, the second largest single-top production mode, is also presented. Finally, measurements of ...

  18. Rasch analysis of the Mini-Mental Adjustment to Cancer Scale (mini-MAC among a heterogeneous sample of long-term cancer survivors: A cross-sectional study

    Directory of Open Access Journals (Sweden)

    Zucca Alison

    2012-05-01

    Full Text Available Abstract Background The mini-Mental Adjustment to Cancer Scale (mini-MAC is a well-recognised, popular measure of coping in psycho-oncology and assesses five cancer-specific coping strategies. It has been suggested that these five subscales could be grouped to form the over-arching adaptive and maladptive coping subscales to facilitate the interpretation and clinical application of the scale. Despite the popularity of the mini-MAC, few studies have examined its psychometric properties among long-term cancer survivors, and further validation of the mini-MAC is needed to substantiate its use with the growing population of survivors. Therefore, this study examined the psychometric properties and dimensionality of the mini-MAC in a sample of long-term cancer survivors using Rasch analysis. Methods RUMM 2030 was used to analyse the mini-MAC data (n=851. Separate Rasch analyses were conducted for each of the original mini-MAC subscales as well as the over-arching adaptive and maladaptive coping subscales to examine summary and individual model fit statistics, person separation index (PSI, response format, local dependency, targeting, item bias (or differential item functioning -DIF, and dimensionality. Results For the fighting spirit, fatalism, and helplessness-hopelessness subscales, a revised three-point response format seemed more optimal than the original four-point response. To achieve model fit, items were deleted from four of the five subscales – Anxious Preoccupation items 7, 25, and 29; Cognitive Avoidance items 11 and 17; Fighting Spirit item 18; and Helplessness-Hopelessness items 16 and 20. For those subscales with sufficient items, analyses supported unidimensionality. Combining items to form the adaptive and maladaptive subscales was partially supported. Conclusions The original five subscales required item deletion and/or rescaling to improve goodness of fit to the Rasch model. While evidence was found for overarching subscales of

  19. Rasch analysis of the Mini-Mental Adjustment to Cancer Scale (mini-MAC) among a heterogeneous sample of long-term cancer survivors: a cross-sectional study.

    Science.gov (United States)

    Zucca, Alison; Lambert, Sylvie D; Boyes, Allison W; Pallant, Julie F

    2012-05-20

    The mini-Mental Adjustment to Cancer Scale (mini-MAC) is a well-recognised, popular measure of coping in psycho-oncology and assesses five cancer-specific coping strategies. It has been suggested that these five subscales could be grouped to form the over-arching adaptive and maladptive coping subscales to facilitate the interpretation and clinical application of the scale. Despite the popularity of the mini-MAC, few studies have examined its psychometric properties among long-term cancer survivors, and further validation of the mini-MAC is needed to substantiate its use with the growing population of survivors. Therefore, this study examined the psychometric properties and dimensionality of the mini-MAC in a sample of long-term cancer survivors using Rasch analysis. RUMM 2030 was used to analyse the mini-MAC data (n=851). Separate Rasch analyses were conducted for each of the original mini-MAC subscales as well as the over-arching adaptive and maladaptive coping subscales to examine summary and individual model fit statistics, person separation index (PSI), response format, local dependency, targeting, item bias (or differential item functioning -DIF), and dimensionality. For the fighting spirit, fatalism, and helplessness-hopelessness subscales, a revised three-point response format seemed more optimal than the original four-point response. To achieve model fit, items were deleted from four of the five subscales - Anxious Preoccupation items 7, 25, and 29; Cognitive Avoidance items 11 and 17; Fighting Spirit item 18; and Helplessness-Hopelessness items 16 and 20. For those subscales with sufficient items, analyses supported unidimensionality. Combining items to form the adaptive and maladaptive subscales was partially supported. The original five subscales required item deletion and/or rescaling to improve goodness of fit to the Rasch model. While evidence was found for overarching subscales of adaptive and maladaptive coping, extensive modifications were

  20. Homogenized group cross sections by Monte Carlo

    International Nuclear Information System (INIS)

    Van Der Marck, S. C.; Kuijper, J. C.; Oppe, J.

    2006-01-01

    Homogenized group cross sections play a large role in making reactor calculations efficient. Because of this significance, many codes exist that can calculate these cross sections based on certain assumptions. However, the application to the High Flux Reactor (HFR) in Petten, the Netherlands, the limitations of such codes imply that the core calculations would become less accurate when using homogenized group cross sections (HGCS). Therefore we developed a method to calculate HGCS based on a Monte Carlo program, for which we chose MCNP. The implementation involves an addition to MCNP, and a set of small executables to perform suitable averaging after the MCNP run(s) have completed. Here we briefly describe the details of the method, and we report on two tests we performed to show the accuracy of the method and its implementation. By now, this method is routinely used in preparation of the cycle to cycle core calculations for HFR. (authors)

  1. Partial cross sections near the higher resonances

    International Nuclear Information System (INIS)

    Falk-Vairant, P.; Valladas, G.

    1961-07-01

    As a continuation of the report given at the 10. Rochester Conference, recent measurements of charge-exchange cross section and π 0 production in π - -p interactions are presented here. Section 1 gives a summary of the known results for the elastic, inelastic, and charge-exchange cross sections. Section 2 presents the behavior of the cross sections in the T=1/2 state, in order to discuss the resonances at 600 and 890 MeV. Section 3 discusses the charge-exchange scattering and the interference term between the T=1/2 and T=3/2 states. Section 4 presents some comments on inelastic processes. This report is reprinted from 'Reviews of Modern Physics', Vol. 33, No. 3, 362-367, July, 1961

  2. Photoproton cross section for /sup 19/F

    Energy Technology Data Exchange (ETDEWEB)

    Tsubota, H [Tohoku Univ., Sendai (Japan). Coll. of General Education; Kawamura, N; Oikawa, S; Uegaki, J I

    1975-02-01

    Proton energy spectra have been measured at 90/sup 0/ for the /sup 19/F(e,e'p)/sup 18/O reaction in the giant resonance region. The (..gamma..,p/sub 0/) and (..gamma..,p/sub 1/) differential cross sections are extracted from the proton energy spectra by using virtual-photon spectra. The integrated differential cross section of the (..gamma..,p/sub 0/) and (..gamma..,p/sub 1/) reactions are 1.80+-0.27 and 0.50+-0.45 MeV-mb/sr, respectively. The results are discussed with the shell model theory by comparing with the (..gamma..,p/sub 0/) cross section of the neighboring 4n-nucleus /sup 20/Ne. A significant increase of the proton yield leaving the non-ground states is found at 25 MeV of the incident electron energy. This is discussed in terms of the core excitation effect.

  3. Prospects for Precision Neutrino Cross Section Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Deborah A. [Fermilab

    2016-01-28

    The need for precision cross section measurements is more urgent now than ever before, given the central role neutrino oscillation measurements play in the field of particle physics. The definition of precision is something worth considering, however. In order to build the best model for an oscillation experiment, cross section measurements should span a broad range of energies, neutrino interaction channels, and target nuclei. Precision might better be defined not in the final uncertainty associated with any one measurement but rather with the breadth of measurements that are available to constrain models. Current experience shows that models are better constrained by 10 measurements across different processes and energies with 10% uncertainties than by one measurement of one process on one nucleus with a 1% uncertainty. This article describes the current status of and future prospects for the field of precision cross section measurements considering the metric of how many processes, energies, and nuclei have been studied.

  4. NNLO jet cross sections by subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Somogyi, G.; Bolzoni, P. [DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Trocsanyi, Z. [CERN PH-TH, on leave from University of Debrecen and Institute of Nuclear Research of HAS, H-4001 P.O.Box 51 (Hungary)

    2010-08-15

    We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of the NNLO subtraction scheme of Refs. [G. Somogyi, Z. Trocsanyi, and V. Del Duca, JHEP 06, 024 (2005), (arXiv:hep-ph/0502226); G. Somogyi and Z. Trocsanyi, (2006), (arXiv:hep-ph/0609041); G. Somogyi, Z. Trocsanyi, and V. Del Duca, JHEP 01, 070 (2007), (arXiv:hep-ph/0609042); G. Somogyi and Z. Trocsanyi, JHEP 01, 052 (2007), (arXiv:hep-ph/0609043)] over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state.

  5. NNLO jet cross sections by subtraction

    International Nuclear Information System (INIS)

    Somogyi, G.; Bolzoni, P.; Trocsanyi, Z.

    2010-01-01

    We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of the NNLO subtraction scheme of Refs. [G. Somogyi, Z. Trocsanyi, and V. Del Duca, JHEP 06, 024 (2005), (arXiv:hep-ph/0502226); G. Somogyi and Z. Trocsanyi, (2006), (arXiv:hep-ph/0609041); G. Somogyi, Z. Trocsanyi, and V. Del Duca, JHEP 01, 070 (2007), (arXiv:hep-ph/0609042); G. Somogyi and Z. Trocsanyi, JHEP 01, 052 (2007), (arXiv:hep-ph/0609043)] over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state.

  6. Optical Model and Cross Section Uncertainties

    Energy Technology Data Exchange (ETDEWEB)

    Herman,M.W.; Pigni, M.T.; Dietrich, F.S.; Oblozinsky, P.

    2009-10-05

    Distinct minima and maxima in the neutron total cross section uncertainties were observed in model calculations using spherical optical potential. We found this oscillating structure to be a general feature of quantum mechanical wave scattering. Specifically, we analyzed neutron interaction with 56Fe from 1 keV up to 65 MeV, and investigated physical origin of the minima.We discuss their potential importance for practical applications as well as the implications for the uncertainties in total and absorption cross sections.

  7. Cross sections for charm production by neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Ushida, N [Aichi Univ. of Education, Kariya (Japan). Dept. of Physics; Kondo, T [Fermi National Accelerator Lab., Batavia, IL (USA); Fujioka, G; Fukushima, J; Takahashi, Y; Tatsumi, S; Yokoyama, C [Kobe Univ. (Japan). Dept. of Physics; Homma, Y; Tsuzuki, Y [Kobe Univ. (Japan). Coll. of Liberal Arts; Bahk, S

    1983-02-03

    The production of charmed particles has been measured using a hybrid emulsion spectrometer in the Fermilab wide-band neutrino beam. The relative cross section for charged current charmed particle production is sigma(v -> ..mu../sup -/c)/sigma(v -> ..mu../sup -/) = 6.5 +- 1.9/1.8%, and the energy dependence of the cross section is presented. One event with charm pair production was observed. A limit of sigma(v -> ..mu..canti c)/sigma(v -> ..mu..c) < 6% (90% CL) is found for the ratio of charged current pair and single charm production.

  8. Covariance Evaluation Methodology for Neutron Cross Sections

    Energy Technology Data Exchange (ETDEWEB)

    Herman,M.; Arcilla, R.; Mattoon, C.M.; Mughabghab, S.F.; Oblozinsky, P.; Pigni, M.; Pritychenko, b.; Songzoni, A.A.

    2008-09-01

    We present the NNDC-BNL methodology for estimating neutron cross section covariances in thermal, resolved resonance, unresolved resonance and fast neutron regions. The three key elements of the methodology are Atlas of Neutron Resonances, nuclear reaction code EMPIRE, and the Bayesian code implementing Kalman filter concept. The covariance data processing, visualization and distribution capabilities are integral components of the NNDC methodology. We illustrate its application on examples including relatively detailed evaluation of covariances for two individual nuclei and massive production of simple covariance estimates for 307 materials. Certain peculiarities regarding evaluation of covariances for resolved resonances and the consistency between resonance parameter uncertainties and thermal cross section uncertainties are also discussed.

  9. Thermal neutron capture cross sections of tellurium isotopes

    Czech Academy of Sciences Publication Activity Database

    Tomandl, Ivo; Honzátko, Jaroslav; Egidy, T. von; Wirth, HF.; Belgya, T.; Lakatos, M.; Szentmiklosi, L.; Revay, Z.; Molnar, GL.; Firestone, RB.; Bondarenko, V.

    2003-01-01

    Roč. 68, č. 6 (2003), 067602 ISSN 0556-2813 R&D Projects: GA ČR GA202/03/0891; GA ČR GA202/99/D087 Institutional research plan: CEZ:AV0Z1048901 Keywords : nuclear -structure * resonance integrals * gamma Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 2.708, year: 2003

  10. A survey of cross-section sensitivity analysis as applied to radiation shielding

    International Nuclear Information System (INIS)

    Goldstein, H.

    1977-01-01

    Cross section sensitivity studies revolve around finding the change in the value of an integral quantity, e.g. transmitted dose, for a given change in one of the cross sections. A review is given of the principal methodologies for obtaining the sensitivity profiles-principally direct calculations with altered cross sections, and linear perturbation theory. Some of the varied applications of cross section sensitivity analysis are described, including the practice, of questionable value, of adjusting input cross section data sets so as to provide agreement with integral experiments. Finally, a plea is made for using cross section sensitivity analysis as a powerful tool for analysing the transport mechanisms of particles in radiation shields and for constructing models of how cross section phenomena affect the transport. Cross section sensitivities in the shielding area have proved to be highly problem-dependent. Without the understanding afforded by such models, it is impossible to extrapolate the conclusions of cross section sensitivity analysis beyond the narrow limits of the specific situations examined in detail. Some of the elements that might be of use in developing the qualitative models are presented. (orig.) [de

  11. Analysis of Sodium-23 Data Cross-Sections for Coolant on Generation IV Reactor - SFR

    International Nuclear Information System (INIS)

    Suwoto; Zuhair

    2009-01-01

    The integral tests of sodium-23 neutron cross-sections for coolant contained in JENDL-3.3, ENDF/B-VII.0, BROND-2.2 and JEFF-3.1 files have been performed. Cross-sections analysis of sodium-23 such as total cross-sections, elastic scattering, in-elastic scattering and radiative capture cross-sections for several temperature i.e. 300K, 800K and 1500K. The sodium-23 total cross-sections analysis based on MAEKER, R.E. experimental result through Broomstick experiment calculation. Differences between among other evaluated nuclear data file for elastic scattering, in-elastic scattering and radiative capture cross-sections were done analyzed and compared to ENDF/B-VII.0 as standard reference. Analysis of total cross-sections sodium-23 through broomstick calculation show JENDL-3.3 file give the best result on C/E statistical average value is 1.1043 compared to another nuclear data files. Differences sodium-23 total cross-sections on JEFF-3.1 file for all temperature work specially for energy 40keV and 1MeV-2MeV is about 0.2%. Meanwhile, relative small differences on in-elastic total scattering cross-sections are shown for all temperatures are about ±0.1% in JENDL-3.3. On the other hand, BROND-2.2 file give ±6% higher on sodium-23 in-elastic total scattering cross sections for energy range 450keV-550keV. Clearly significant differences on sodium-23 radiative capture cross sections for BROND-2.2 file especially in energy 109.659keV is somewhat higher than 446%, otherwise JENDL-3.3 and JEFF-3.1 give 16% higher than ENDF/B-VII.0 file. Overall result show that JENDL-3.3, ENDFB-VII.0, BROND-2.2 and JEFF-3.1 have little bit differences in total, elastic scattering, in-elastic scattering total cross sections, except BROND-2.2 file due to radiative capture cross-sections with larger discrepancies. (author)

  12. Ecological Panel Inference from Repeated Cross Sections

    NARCIS (Netherlands)

    Pelzer, Ben; Eisinga, Rob; Franses, Philip Hans

    2004-01-01

    This chapter presents a Markov chain model for the estimation of individual-level binary transitions from a time series of independent repeated cross-sectional (RCS) samples. Although RCS samples lack direct information on individual turnover, it is demonstrated here that it is possible with these

  13. Validation of evaluated neutron standard cross sections

    International Nuclear Information System (INIS)

    Badikov, S.; Golashvili, T.

    2008-01-01

    Some steps of the validation and verification of the new version of the evaluated neutron standard cross sections were carried out. In particular: -) the evaluated covariance data was checked for physical consistency, -) energy-dependent evaluated cross-sections were tested in most important neutron benchmark field - 252 Cf spontaneous fission neutron field, -) a procedure of folding differential standard neutron data in group representation for preparation of specialized libraries of the neutron standards was verified. The results of the validation and verification of the neutron standards can be summarized as follows: a) the covariance data of the evaluated neutron standards is physically consistent since all the covariance matrices of the evaluated cross sections are positive definite, b) the 252 Cf spectrum averaged standard cross-sections are in agreement with the evaluated integral data (except for 197 Au(n,γ) reaction), c) a procedure of folding differential standard neutron data in group representation was tested, as a result a specialized library of neutron standards in the ABBN 28-group structure was prepared for use in reactor applications. (authors)

  14. Stability of tokamaks with elongated cross section

    International Nuclear Information System (INIS)

    An, C.H.; Bateman, G.

    1978-08-01

    Fixed boundary n = 1 MHD instabilities are studied computationally as a function of diamagnetism (β/sub pol/) and current profile in elongated toroidal equilibria (1 2) or a diamagnetic plasma (β/sub pol/ > 1) with only a mildly elongated cross section

  15. Modelisation of the fission cross section

    International Nuclear Information System (INIS)

    Morariu, Claudia

    2013-03-01

    The neutron cross sections of four nuclear systems (n+ 235 U, n+ 233 U, n+ 241 Am and n+ 237 Np) are studied in the present document. The target nuclei of the first case, like 235 U and 239 Pu, have a large fission cross section after the absorption of thermal neutrons. These nuclei are called 'fissile' nuclei. The other type of nuclei, like 237 Np and 241 Am, fission mostly with fast neutrons, which exceed the fission threshold energy. These types of nuclei are called 'fertile'. The compound nuclei of the fertile nuclei have a binding energy higher than the fission barrier, while for the fissile nuclei the binding energy is lower than the fission barrier. In this work, the neutron induced cross sections for both types of nuclei are evaluated in the fast energy range. The total, reaction and shape-elastic cross sections are calculated by the coupled channel method of the optical model code ECIS, while the compound nucleus mechanism are treated by the statistical models implemented in the codes STATIS, GNASH and TALYS. The STATIS code includes a refined model of the fission process. Results from the theoretical calculations are compared with data retrieved from the experimental data base EXFOR. (author) [fr

  16. Photoelectric absorption cross sections with variable abundances

    Science.gov (United States)

    Balucinska-Church, Monika; Mccammon, Dan

    1992-01-01

    Polynomial fit coefficients have been obtained for the energy dependences of the photoelectric absorption cross sections of 17 astrophysically important elements. These results allow the calculation of X-ray absorption in the energy range 0.03-10 keV in material with noncosmic abundances.

  17. (, 3) Differential cross section of He

    Indian Academy of Sciences (India)

    The angular distribution of the five-fold differential cross section for the electron impact double ionization of He (21 ) and He (23 ) has been studied. The kinematical conditions for maxima/minima in the angular distribution for the two cases have been compared. The two-step process for the double ionization is found to ...

  18. Precise relative cross sections for np scattering

    International Nuclear Information System (INIS)

    Goetz, J.; Brogli-Gysin, C.; Hammans, M.; Haffter, P.; Henneck, R.; Jourdan, J.; Masson, G.; Qin, L.M.; Robinson, S.; Sick, I.; Tuccillo, M.

    1994-01-01

    We present data on the differential cross section for neutron-proton scattering for an incident neutron energy of 67 MeV. These data allow a precise determination of the 1 P 1 phase which, in phase-shift analyses, is strongly correlated with the S-D amplitude which we are measuring via different observables. ((orig.))

  19. Symmetric charge transfer cross section of uranium

    International Nuclear Information System (INIS)

    Shibata, Takemasa; Ogura, Koichi

    1995-03-01

    Symmetric charge transfer cross section of uranium was calculated under consideration of reaction paths. In the charge transfer reaction a d 3/2 electron in the U atom transfers into the d-electron site of U + ( 4 I 9/2 ) ion. The J value of the U atom produced after the reaction is 6, 5, 4 or 3, at impact energy below several tens eV, only resonant charge transfer in which the product atom is ground state (J=6) takes place. Therefore, the cross section is very small (4-5 x 10 -15 cm 2 ) compared with that considered so far. In the energy range of 100-1000eV the cross section increases with the impact energy because near resonant charge transfer in which an s-electron in the U atom transfers into the d-electron site of U + ion. Charge transfer cross section between U + in the first excited state (289 cm -1 ) and U in the ground state was also obtained. (author)

  20. LAMBDA p total cross-section measurement

    CERN Multimedia

    CERN PhotoLab

    1970-01-01

    A view of the apparatus used for the LAMBDA p total cross-section measurement at the time of its installation. The hyperons decaying into a proton and a pion in the conical tank in front were detected in the magnet spectrometer in the upper half of the picture. A novel detection technique using exclusively multiwire proportional chambers was employed.

  1. Fe L-shell Excitation Cross Section Measurements on EBIT-I

    Science.gov (United States)

    Chen, Hui; Beiersdorfer, P.; Brown, G.; Boyce, K.; Kelley, R.; Kilbourne, C.; Porter, F.; Gu, M. F.; Kahn, S.

    2006-09-01

    We report the measurement of electron impact excitation cross sections for the strong iron L-shell 3-2 lines of Fe XVII to Fe XXIV at the LLNL EBIT-I electron beam ion trap using a crystal spectrometer and NASA-Goddard Space Flight Center's 6x6 pixel array microcalorimeter. The cross sections were determined by direct normalization to the well-established cross sections for radiative electron capture. Our results include the excitation cross section for over 50 lines at multiple electron energies. Although we have found that for 3C line in Fe XVII the measured cross sections differ significantly from theory, in most cases the measurements and theory agree within 20%. This work was performed under the auspices of the U.S. DOE by LLNL under contract No. W-7405-Eng-48 and supported by NASA APRA grants to LLNL, GSFC, and Stanford University.

  2. Measurement cross sections for radioisotopes production

    International Nuclear Information System (INIS)

    Garrido, E.

    2011-01-01

    New radioactive isotopes for nuclear medicine can be produced using particle accelerators. This is one goal of Arronax, a high energy - 70 MeV - high intensity - 2*350 μA - cyclotron set up in Nantes. A priority list was established containing β - - 47 Sc, 67 Cu - β + - 44 Sc, 64 Cu, 82 Sr/ 82 Rb, 68 Ge/ 68 Ga - and α emitters - 211 At. Among these radioisotopes, the Scandium 47 and the Copper 67 have a strong interest in targeted therapy. The optimization of their productions required a good knowledge of their cross-sections but also of all the contaminants created during irradiation. We launched on Arronax a program to measure these production cross-sections using the Stacked-Foils' technique. It consists in irradiating several groups of foils - target, monitor and degrader foils - and in measuring the produced isotopes by γ-spectrometry. The monitor - nat Cu or nat Ni - is used to correct beam loss whereas degrader foils are used to lower beam energy. We chose to study the nat Ti(p,X) 47 Sc and 68 Zn(p,2p) 67 Cu reactions. Targets are respectively natural Titanium foil - bought from Goodfellow - and enriched Zinc 68 deposited on Silver. In the latter case, Zn targets were prepared in-house - electroplating of 68 Zn - and a chemical separation between Copper and Gallium isotopes has to be made before γ counting. Cross-section values for more than 40 different reactions cross-sections have been obtained from 18 MeV to 68 MeV. A comparison with the Talys code is systematically done. Several parameters of theoretical models have been studied and we found that is not possible to reproduce faithfully all the cross-sections with a given set of parameters. (author)

  3. Market skewness risk and the cross section of stock returns

    DEFF Research Database (Denmark)

    Chang, B.Y.; Christoffersen, Peter; Jacobs, K.

    2013-01-01

    The cross section of stock returns has substantial exposure to risk captured by higher moments of market returns. We estimate these moments from daily Standard & Poor's 500 index option data. The resulting time series of factors are genuinely conditional and forward-looking. Stocks with high...... exposure to innovations in implied market skewness exhibit low returns on average. The results are robust to various permutations of the empirical setup. The market skewness risk premium is statistically and economically significant and cannot be explained by other common risk factors such as the market...... excess return or the size, book-to-market, momentum, and market volatility factors, or by firm characteristics....

  4. Absolute measurements of neutron cross sections. Progress report

    International Nuclear Information System (INIS)

    1984-11-01

    In the photoneutron laboratory, we have completed a major refurbishing of experimental facilities and begun work on measurements of the capture cross section in thorium and U-238. In the 14 MeV neutron experimental bay, work continues on the measurement of 14 MeV neutron induced reactions of interest as standards or because of their technological importance. First results have been obtained over the past year, and we are extending these measurements along the lines outlined in our proposal of a year ago

  5. Contribution to uncertainties evaluation for fast reactors neutronic cross sections

    International Nuclear Information System (INIS)

    Privas, Edwin

    2015-01-01

    The thesis has been motivated by a wish to increase the uncertainty knowledge on nuclear data, for safety criteria. It aims the cross sections required by core calculation for sodium fast reactors (SFR), and new tools to evaluate its.The main objective of this work is to provide new tools in order to create coherent evaluated files, with reliable and mastered uncertainties. To answer those problematic, several methods have been implemented within the CONRAD code, which is developed at CEA of Cadarache. After a summary of all the elements required to understand the evaluation world, stochastic methods are presented in order to solve the Bayesian inference. They give the evaluator more information about probability density and they also can be used as validation tools. The algorithms have been successfully tested, despite long calculation time. Then, microscopic constraints have been implemented in CONRAD. They are defined as new information that should be taken into account during the evaluation process. An algorithm has been developed in order to solve, for example, continuity issues between two energy domains, with the Lagrange multiplier formalism. Another method is given by using a marginalization procedure, in order to either complete an existing evaluation with new covariance or add systematic uncertainty on an experiment described by two theories. The algorithms are well performed along examples, such the 238 U total cross section. The last parts focus on the integral data feedback, using methods of integral data assimilation to reduce the uncertainties on cross sections. This work ends with uncertainty reduction on key nuclear reactions, such the capture and fission cross sections of 238 U and 239 Pu, thanks to PROFIL and PROFIL-2 experiments in Phenix and the Jezebel benchmark. (author) [fr

  6. Adjusting multistate capture-recapture models for misclassification bias: manatee breeding proportions

    Science.gov (United States)

    Kendall, W.L.; Hines, J.E.; Nichols, J.D.

    2003-01-01

    Matrix population models are important tools for research and management of populations. Estimating the parameters of these models is an important step in applying them to real populations. Multistate capture-recapture methods have provided a useful means for estimating survival and parameters of transition between locations or life history states but have mostly relied on the assumption that the state occupied by each detected animal is known with certainty. Nevertheless, in some cases animals can be misclassified. Using multiple capture sessions within each period of interest, we developed a method that adjusts estimates of transition probabilities for bias due to misclassification. We applied this method to 10 years of sighting data for a population of Florida manatees (Trichechus manatus latirostris) in order to estimate the annual probability of transition from nonbreeding to breeding status. Some sighted females were unequivocally classified as breeders because they were clearly accompanied by a first-year calf. The remainder were classified, sometimes erroneously, as nonbreeders because an attendant first-year calf was not observed or was classified as more than one year old. We estimated a conditional breeding probability of 0.31 + 0.04 (estimate + 1 SE) when we ignored misclassification bias, and 0.61 + 0.09 when we accounted for misclassification.

  7. AXMIX program for cross section mixing and library arrangement

    International Nuclear Information System (INIS)

    Haynes, G.C.

    1976-03-01

    AXMIX is a FORTRAN IV computer code written to provide the user a tool for creating cross-section data sets for ANISN and DOT from cross-section sets already available on cards, nuclide-organized libraries, and group-independent data sets. Numerous options, including adjointing, P/sub n/ adjustments, and changing table length, are available to give the user broad flexibility. The number of energy groups which will fit into the core allocated is determined first. If all groups will fit, the solution is straightforward; if not, then the maximum number of groups which will fit is processed repeatedly by using direct access I/O and storage disks. Some flexibility in applying AXMIX is lost when cross sections to be processed contain upscatter. A special section on upscatter is included in the report. AXMIX is written for IBM System 360 computers with at least 150K bytes of memory. Problems of a practical nature require from 2 to 20 seconds of CPU time on a 360/91 computer. Running time is inversely proportional to the number of groups of data which will fit into core memory. I/O time is 50 to 100 times CPU time

  8. Formalism for neutron cross section covariances in the resonance region using kernel approximation

    Energy Technology Data Exchange (ETDEWEB)

    Oblozinsky, P.; Cho,Y-S.; Matoon,C.M.; Mughabghab,S.F.

    2010-04-09

    We describe analytical formalism for estimating neutron radiative capture and elastic scattering cross section covariances in the resolved resonance region. We use capture and scattering kernels as the starting point and show how to get average cross sections in broader energy bins, derive analytical expressions for cross section sensitivities, and deduce cross section covariances from the resonance parameter uncertainties in the recently published Atlas of Neutron Resonances. The formalism elucidates the role of resonance parameter correlations which become important if several strong resonances are located in one energy group. Importance of potential scattering uncertainty as well as correlation between potential scattering and resonance scattering is also examined. Practical application of the formalism is illustrated on {sup 55}Mn(n,{gamma}) and {sup 55}Mn(n,el).

  9. Impact of newly-measured gadolinium cross sections on BWR fuel rod reaction rate distributions

    Energy Technology Data Exchange (ETDEWEB)

    Jatuff, F.; Perret, G.; Murphy, M.; Grimm, P.; Seiler, R. [Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland); Chawla, R. [Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland); Ecole Polytechnique Federal de Lausanne, CH-1015 Lausanne (Switzerland)

    2008-07-01

    Recent measurements of capture and total cross sections performed at the Rensselaer Polytechnic Institute in the USA confirmed many of the gadolinium thermal and resonant neutron cross section parameters within uncertainties, but they also showed up important discrepancies well out of uncertainties, such as an approx11% overestimation of the {sup 157}Gd thermal capture cross section in ENDF/B-VI and -VII with respect to the newly measured data. In this work, the impact of the newly measured gadolinium cross sections on BWR reactor physics parameters has been preliminarily evaluated. The comparisons of rod-by-rod fission rate and modified conversion ratio predictions with selected cold critical experiments at the PROTEUS reactor in Switzerland show the potential to resolve long-term unexplained discrepancies. (authors)

  10. (n,{alpha}) cross section measurement of gaseous sample using gridded ionization chamber. Cross section determination

    Energy Technology Data Exchange (ETDEWEB)

    Sanami, Toshiya; Baba, Mamoru; Saito, Keiichiro; Ibara, Yasutaka; Hirakawa, Naohiro [Tohoku Univ., Sendai (Japan). Faculty of Engineering

    1997-03-01

    We are developing a method of (n,{alpha}) cross section measurement using gaseous samples in a gridded ionization chamber (GIC). This method enables cross section measurements in large solid angle without the distortion by the energy loss in a sample, but requires a method to estimate the detection efficiency. We solve this problem by using GIC signals and a tight neutron collimation. The validity of this method was confirmed through the {sup 12}C(n,{alpha}{sub 0}){sup 9}Be measurement. We applied this method to the {sup 16}O(n,{alpha}){sup 13}C cross section around 14.1 MeV. (author)

  11. R-matrix analysis of the /sup 239/Pu neutron cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Saussure, G. de; Perez, R.B.; Macklin, R.L.

    1986-03-01

    /sup 239/Pu neutron cross-section data in the resolved resonance region were analyzed with the R-Matrix Bayesian Program SAMMY. Below 30 eV the cross sections computed with the multilevel parameters are consistent with recent fission and transmission measurements as well as with older capture and alpha measurements. Above 30 eV no suitable transmission data were available and only fission cross-section measurements were analyzed. However, since the analysis conserves the complete covariance matrix, the analysis can be updated by the Bayes method as transmission measurements become available. To date, the analysis of the fission measurements has been completed up to 300 eV.

  12. Preparation of multigroup lumped fission product cross-sections from ENDF/B-VI for FBRs

    International Nuclear Information System (INIS)

    Devan, K.; Gopalakrishnan, V.; Mohanakrishnan, P.; Sridharan, M.S.

    1997-01-01

    Multigroup pseudo fission product cross-sections were computed from the American evaluated nuclear data library ENDF/B-VI, corresponding to various burnups of the proposed 500 MWe prototype fast breeder reactor (PFBR), in India. The data were derived from the cross-sections of 111 selected fission products that account for almost complete capture of fission products in an FBR. The dependence of burnup on the pseudo fission product cross-sections, and comparison with other data sets, viz. JNDC, ENDF/B-IV and ABBN, are discussed. (author)

  13. Within the framework of the new fuel cycle {sup 232}Th/{sup 233}U, determination of the {sup 233}Pa(n.{gamma}) radiative capture cross section for neutron energies ranging between 0 and 1 MeV; Dans le cadre du nouveau cycle de combustible {sup 232}Th/{sup 233}U, determination de la section efficace de capture radiative {sup 233}Pa(n,{gamma}) pour des energies de neutrons comprises entre 0 et 1 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Boyer, S

    2004-10-15

    The Thorium cycle Th{sup 232}/U{sup 233} may face brilliant perspectives through advanced concepts like molten salt reactors or accelerator driven systems but it lacks accurate nuclear data concerning some nuclei. Pa{sup 233} is one of these nuclei, its high activity makes the direct measurement of its radiative neutron capture cross-section almost impossible. This difficulty has been evaded by considering the transfer reaction Th{sup 232}(He{sup 3},p)Pa{sup 234}* in which the Pa{sup 234} nucleus is produced in various excited states according to the amount of energy available in the reaction. The first chapter deals with the thorium cycle and its assets to contribute to the quenching of the fast growing world energy demand. The second chapter gives a detailed description of the experimental setting. A scintillation detector based on deuterated benzene (C{sub 6}D{sub 6}) has been used to counter gamma ray cascades. The third chapter is dedicated to data analysis. In the last chapter we compare our experimental results with ENDF and JENDL data and with computed values from 2 statistical models in the 0-1 MeV neutron energy range. Our results disagree clearly with evaluated data: our values are always above ENDF and JENDL data but tend to near computed values. We have also perform the measurement of the radiative neutron cross-section of Pa{sup 231} for a 110 keV neutron: {sigma}(n,{gamma}) 2.00 {+-} 0.14 barn. (A.C.)

  14. Rotational averaging of multiphoton absorption cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Friese, Daniel H., E-mail: daniel.h.friese@uit.no; Beerepoot, Maarten T. P.; Ruud, Kenneth [Centre for Theoretical and Computational Chemistry, University of Tromsø — The Arctic University of Norway, N-9037 Tromsø (Norway)

    2014-11-28

    Rotational averaging of tensors is a crucial step in the calculation of molecular properties in isotropic media. We present a scheme for the rotational averaging of multiphoton absorption cross sections. We extend existing literature on rotational averaging to even-rank tensors of arbitrary order and derive equations that require only the number of photons as input. In particular, we derive the first explicit expressions for the rotational average of five-, six-, and seven-photon absorption cross sections. This work is one of the required steps in making the calculation of these higher-order absorption properties possible. The results can be applied to any even-rank tensor provided linearly polarized light is used.

  15. Measurements of neutron spallation cross section. 2

    Energy Technology Data Exchange (ETDEWEB)

    Kim, E.; Nakamura, T. [Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center; Imamura, M.; Nakao, N.; Shibata, S.; Uwamino, Y.; Nakanishi, N.; Tanaka, Su.

    1997-03-01

    Neutron spallation cross section of {sup 59}Co(n,xn){sup 60-x}Co, {sup nat}Cu(n,sp){sup 56}Mn, {sup nat}Cu(n,sp){sup 58}Co, {sup nat}Cu(n,xn){sup 60}Cu, {sup nat}Cu(n,xn){sup 61}Cu and {sup nat}Cu(n,sp){sup 65}Ni was measured in the quasi-monoenergetic p-Li neutron fields in the energy range above 40 MeV which have been established at three AVF cyclotron facilities of (1) INS of Univ. of Tokyo, (2) TIARA of JAERI and (3) RIKEN. Our experimental data were compared with the ENDF/B-VI high energy file data by Fukahori and the calculated cross section data by Odano. (author)

  16. Structured ion impact: Doubly differential cross sections

    International Nuclear Information System (INIS)

    DuBois, R.D.

    1987-01-01

    The electron emission in coincidence with a projectile that has been ionized has been measured, thus making it possible to separate and identify electrons resulting from these various mechanisms. In 1985, coincidence doubly differential cross sections were measured for 400 to 750 keV/atomic mass unit (amu) He + impact on He, Ne, Ar, Kr, and H 2 O. Cross sections were measured for selected angles and for electron energies ranging from 10 to 1000 eV. Because of the coincidence mode of measurement, the total electron emission was subdivided into its target emission and its projectile emission components. The most interesting findings were that target ionization does not account for the electron emission spectrum at lower electron energies. A sizable percentage of these low-energy electrons were shown to originate as a result of simultaneous projectile/target ionizations. Similar features were observed for all targets and impact energies that were studied

  17. Electron-collision cross sections for iodine

    International Nuclear Information System (INIS)

    Zatsarinny, O.; Bartschat, K.; Garcia, G.; Blanco, F.; Hargreaves, L.R.; Jones, D.B.; Murrie, R.; Brunton, J.R.; Brunger, M.J.; Hoshino, M.; Buckman, S.J.

    2011-01-01

    We present results from a joint experimental and theoretical study of elastic electron scattering from atomic iodine. The experimental results were obtained by subtracting known cross sections from the measured data obtained with a pyrolyzed mixed beam containing a variety of atomic and molecular species. The calculations were performed using both a fully relativistic Dirac B-spline R-matrix (close-coupling) method and an optical model potential approach. Given the difficulty of the problem, the agreement between the two sets of theoretical predictions and the experimental data for the angle-differential and the angle-integrated elastic cross sections at 40 eV and 50 eV is satisfactory.

  18. Absolute partial photoionization cross sections of ethylene

    Science.gov (United States)

    Grimm, F. A.; Whitley, T. A.; Keller, P. R.; Taylor, J. W.

    1991-07-01

    Absolute partial photoionization cross sections for ionization out of the first four valence orbitals to the X 2B 3u, A 2B 3g, B 2A g and C 2B 2u states of the C 2H 4+ ion are presented as a function of photon energy over the energy range from 12 to 26 eV. The experimental results have been compared to previously published relative partial cross sections for the first two bands at 18, 21 and 24 eV. Comparison of the experimental data with continuum multiple scattering Xα calculations provides evidence for extensive autoionization to the X 2B 3u state and confirms the predicted shape resonances in ionization to the A 2B 3g and B 2A g states. Identification of possible transitions for the autoionizing resonances have been made using multiple scattering transition state calculations on Rydberg excited states.

  19. Radar cross section measurements using terahertz waves

    DEFF Research Database (Denmark)

    Iwaszczuk, Krzysztof; Heiselberg, Henning; Jepsen, Peter Uhd

    2010-01-01

    Radar cross sections at terahertz frequencies are measured on scale models of aircrafts. A time domain broadband THz system generates freely propagating THz pulses measured with sub-picosecond time resolution. The THz radiation is generated using fs laser pulses by optical rectification...... in order to measure realistic radar cross sections. RCS polar and azimuthal angle plots of F-16 and F-35 are presented....... in a lithium niobate crystal with application of the tilted wave front method, resulting in high electric field THz pulses with a broad band spectrum from 100 GHz up to 4 THz. The corresponding wave lengths are two orders of magnitude smaller than normal radars and we therefore use scale models of size 5-10 cm...

  20. Double differential cross sections of ethane molecule

    Science.gov (United States)

    Kumar, Rajeev

    2018-05-01

    Partial and total double differential cross sections corresponding to various cations C2H6+, C2H4+, C2H5+, C2H3+, C2H2+, CH3+, H+, CH2+, C2H+, H2+, CH+, H3+, C2+ and C+ produced during the direct and dissociative electron ionization of Ethane (C2H6) molecule have been calculated at fixed impinging electron energies 200 and 500eV by using modified Jain-Khare semi empirical approach. The calculation for double differential cross sections is made as a function of energy loss suffered by primary electron and angle of incident. To the best of my knowledge no other data is available for the comparison.

  1. Cross sections required for FMIT dosimetry

    International Nuclear Information System (INIS)

    Gold, R.; McElroy, W.N.; Lippincott, E.P.; Mann, F.M.; Oberg, D.L.; Roberts, J.H.; Ruddy, F.H.

    1980-01-01

    The Fusion Materials Irradiation Test (FMIT) facility, currently under construction, is designed to produce a high flux of high energy neutrons for irradiation effects experiments on fusion reactor materials. Characterization of the flux-fluence-spectrum in this rapidly varying neutron field requires adaptation and extension of currently available dosimetry techniques. This characterization will be carried out by a combination of active, passive, and calculational dosimetry. The goal is to provide the experimenter with accurate neutron flux-fluence-spectra at all positions in the test cell. Plans have been completed for a number of experimental dosimetry stations and provision for these facilities has been incorporated into the FMIT design. Overall needs of the FMIT irradiation damage program delineate goal accuracies for dosimetry that, in turn, create new requirements for high energy neutron cross section data. Recommendations based on these needs have been derived for required cross section data and accuracies

  2. Elliptical cross section fuel rod study II

    International Nuclear Information System (INIS)

    Taboada, H.; Marajofsky, A.

    1996-01-01

    In this paper it is continued the behavior analysis and comparison between cylindrical fuel rods of circular and elliptical cross sections. Taking into account the accepted models in the literature, the fission gas swelling and release were studied. An analytical comparison between both kinds of rod reveals a sensible gas release reduction in the elliptical case, a 50% swelling reduction due to intragranular bubble coalescence mechanism and an important swelling increase due to migration bubble mechanism. From the safety operation point of view, for the same linear power, an elliptical cross section rod is favored by lower central temperatures, lower gas release rates, greater gas store in ceramic matrix and lower stored energy rates. (author). 6 refs., 8 figs., 1 tab

  3. Total reaction cross sections and neutron-removal cross sections of neutron-rich light nuclei measured by the COMBAS fragment-separator

    Science.gov (United States)

    Hue, B. M.; Isataev, T.; Erdemchimeg, B.; Artukh, A. G.; Aznabaev, D.; Davaa, S.; Klygin, S. A.; Kononenko, G. A.; Khuukhenkhuu, G.; Kuterbekov, K.; Lukyanov, S. M.; Mikhailova, T. I.; Maslov, V. A.; Mendibaev, K.; Sereda, Yu M.; Penionzhkevich, Yu E.; Vorontsov, A. N.

    2017-12-01

    Preliminary results of measurements of the total reaction cross sections σR and neutron removal cross section σ-xn for weakly bound 6He, 8Li, 9Be and 10Be nuclei at energy range (20-35) A MeV with 28Si target is presented. The secondary beams of light nuclei were produced by bombardment of the 22Ne (35 A MeV) primary beam on Be target and separated by COMBAS fragment-separator. In dispersive focal plane a horizontal slit defined the momentum acceptance as 1% and a wedge degrader of 200 μm Al was installed. The Bρ of the second section of the fragment-separator was adjusted for measurements in energy range (20-35) A MeV. Two-neutron removal cross sections for 6He and 10Be and one -neutron removal cross sections 8Li and 9Be were measured.

  4. Differential Cross-Sections for pi- p --> gamma n in the First Resonance Region

    CERN Document Server

    Guex-Le Lan, Huong; Hilscher, H; Joseph, C L; Schmitt, H; Tran, M T; Truöl, P; Vaucher, B; Winkelmann, E; Zupancic, Crtomir; Joseph, C L no 1; Tran, M T no 1; Vaucher, B no 1; Winkelmann, E no 1; Bayer, W no 2; Hilscher, H no 2; Schmitt, H no 2; Zupancic, C no 2; Truöl, P no 3; Guex, L H no 1

    1975-01-01

    Differential cross-sections for negative pion radiative capture on protons at c.m. angles of 60°, 90°, and 120° have been measured at nine incident laboratory energies between 110 and 270 MeV. Comparison with measured cross-sections for pion photoproduction and with conventional multipole analyses shows neither evidence for a violation of time reversal invariance nor for an isotensor component of the electromagnetic current of hardrons. Record added 1974-09-01, las

  5. Electron collision cross sections and radiation chemistry

    International Nuclear Information System (INIS)

    Hatano, Y.

    1983-01-01

    A survey is given of the cross section data needs in radiation chemistry, and of the recent progress in electron impact studies on dissociative excitation of molecules. In the former some of the important target species, processes, and collision energies are presented, while in the latter it is demonstrated that radiation chemistry is a source of new ideas and information in atomic collision research. 37 references, 4 figures

  6. Absolute photoionization cross sections of atomic oxygen

    Science.gov (United States)

    Samson, J. A. R.; Pareek, P. N.

    1985-01-01

    The absolute values of photoionization cross sections of atomic oxygen were measured from the ionization threshold to 120 A. An auto-ionizing resonance belonging to the 2S2P4(4P)3P(3Do, 3So) transition was observed at 479.43 A and another line at 389.97 A. The experimental data is in excellent agreement with rigorous close-coupling calculations that include electron correlations in both the initial and final states.

  7. Total dissociation cross section of halo nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Formanek, J. [Karlova Univ., Prague (Czech Republic). Fakulta Matematicko-Fyzikalni; Lombard, R.J. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire

    1996-10-01

    Calculations of the total dissociation cross section is performed in the impact parameter representation. The case of {sup 11}Be and {sup 11}Li loosing one and two neutron(s), respectively, by collision on a {sup 12}C target, which remains in its ground state are discussed. The results are found to depend essentially on the rms radius of the halo wave function. (author). 12 refs.

  8. Measurements of Fission Cross Sections of Actinides

    CERN Multimedia

    Wiescher, M; Cox, J; Dahlfors, M

    2002-01-01

    A measurement of the neutron induced fission cross sections of $^{237}$Np, $^{241},{243}$Am and of $^{245}$Cm is proposed for the n_TOF neutron beam. Two sets of fission detectors will be used: one based on PPAC counters and another based on a fast ionization chamber (FIC). A total of 5x10$^{18}$ protons are requested for the entire fission measurement campaign.

  9. Cross section of the CMS solenoid

    CERN Multimedia

    Tejinder S. Virdee, CERN

    2005-01-01

    The pictures show a cross section of the CMS solenoid. One can see four layers of the superconducting coil, each of which contains the superconductor (central part, copper coloured - niobium-titanium strands in a copper coating, made into a "Rutherford cable"), surrounded by an ultra-pure aluminium as a magnetic stabilizer, then an aluminium alloy as a mechanical stabilizer. Besides the four layers there is an aluminium mechanical piece that includes pipes that transport the liquid helium.

  10. Cross sections for multistep direct reactions

    International Nuclear Information System (INIS)

    Demetriou, Paraskevi; Marcinkowski, Andrzej; Marianski, Bohdan

    2002-01-01

    Inelastic scattering and charge-exchange reactions have been analysed at energies ranging from 14 to 27 MeV using the modified multistep direct reaction theory (MSD) of Feshbach, Kerman and Koonin. The modified theory considers the non-DWBA matrix elements in the MSD cross section formulae and includes both incoherent particle-hole excitations and coherent collective excitations in the continuum, according to the prescriptions. The results show important contributions from multistep processes at all energies considered. (author)

  11. Inclusive jet cross section at D0

    International Nuclear Information System (INIS)

    Bhattacharjee, M.

    1996-09-01

    Preliminary measurement of the central (|η| ≤ 0.5) inclusive jet cross sections for jet cone sizes of 1.0, 0.7, and 0.5 at D null based on the 1992-1993 (13.7 pb -1 ) and 1994-1995 (90 pb -1 ) data samples are presented. Comparisons to Next-to-Leading Order (NLO) Quantum Chromodynamics (QCD) calculations are made

  12. Fully double-logarithm-resummed cross sections

    International Nuclear Information System (INIS)

    Albino, S.; Bolzoni, P.; Kniehl, B.A.; Kotikov, A.

    2011-01-01

    We calculate the complete double logarithmic contribution to cross sections for semi-inclusive hadron production in the modified minimal-subtraction (MS-bar) scheme by applying dimensional regularization to the double logarithm approximation. The full double logarithmic contribution to the coefficient functions for inclusive hadron production in e + e - annihilation is obtained in this scheme for the first time. Our result agrees with all fixed order results in the literature, which extend to next-to-next-to-leading order.

  13. Atomic-process cross section data, 1

    International Nuclear Information System (INIS)

    1974-12-01

    Compiled by the Data Study Group, the data are intended for fusion plasma physics research. Cross sections of the latest experimental and theoretic studies cover the processes involving H,D,T as principal plasma materials as well as photons and electrons: emission and absorption of electromagnetic wave, electron collision, ion collision, recombination, neutral atom mutual collision, etc. Edition is so made to enable the future renewal by users. (J.P.N.)

  14. MXS cross-section preprocessor user's manual

    International Nuclear Information System (INIS)

    Parker, F.; Ishikawa, M.; Luck, L.

    1987-03-01

    The MXS preprocessor has been designed to reduce the execution time of programs using isotopic cross-section data and to both reduce the execution time and improve the accuracy of shielding-factor interpolation in the SIMMER-II accident analysis program. MXS is a dual-purpose preprocessing code to: (1) mix isotopes into materials and (2) fit analytic functions to the shelf-shielding data. The program uses the isotope microscopic neutron cross-section data from the CCCC standard interface file ISOTXS and the isotope Bondarenko self-shielding data from the CCCC standard interface file BRKOXS to generate cross-section and self-shielding data for materials. The materials may be a mixture of several isotopes. The self-shielding data for the materials may be the actual shielding factors or a set of coefficients for functions representing the background dependence of the shielding factors. A set of additional data is given to describe the functions necessary to interpolate the shielding factors over temperature

  15. Quality Quantification of Evaluated Cross Section Covariances

    International Nuclear Information System (INIS)

    Varet, S.; Dossantos-Uzarralde, P.; Vayatis, N.

    2015-01-01

    Presently, several methods are used to estimate the covariance matrix of evaluated nuclear cross sections. Because the resulting covariance matrices can be different according to the method used and according to the assumptions of the method, we propose a general and objective approach to quantify the quality of the covariance estimation for evaluated cross sections. The first step consists in defining an objective criterion. The second step is computation of the criterion. In this paper the Kullback-Leibler distance is proposed for the quality quantification of a covariance matrix estimation and its inverse. It is based on the distance to the true covariance matrix. A method based on the bootstrap is presented for the estimation of this criterion, which can be applied with most methods for covariance matrix estimation and without the knowledge of the true covariance matrix. The full approach is illustrated on the 85 Rb nucleus evaluations and the results are then used for a discussion on scoring and Monte Carlo approaches for covariance matrix estimation of the cross section evaluations

  16. NNLO jet cross sections by subtraction

    Science.gov (United States)

    Somogyi, G.; Bolzoni, P.; Trócsányi, Z.

    2010-08-01

    We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of the NNLO subtraction scheme of Refs. [G. Somogyi, Z. Trócsányi, and V. Del Duca, JHEP 06, 024 (2005), arXiv:hep-ph/0502226; G. Somogyi and Z. Trócsányi, (2006), arXiv:hep-ph/0609041; G. Somogyi, Z. Trócsányi, and V. Del Duca, JHEP 01, 070 (2007), arXiv:hep-ph/0609042; G. Somogyi and Z. Trócsányi, JHEP 01, 052 (2007), arXiv:hep-ph/0609043] over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state.

  17. Re/Os cosmochronometer: measurement of neutron cross sections

    International Nuclear Information System (INIS)

    Mosconi, M.

    2007-01-01

    This experimental work is devoted to the improved assessment of the Re/Os cosmochronometer. The dating technique is based on the decay of 187 Re (t 1/2 =41.2 Gyr) into 187 Os and determines the age of the universe by the time of onset of nucleosynthesis. The nucleosynthesis mechanisms, which are responsible for the 187 Re/ 187 Os pair, provide the possibility to identify the radiogenic fraction of 187 Os exclusively by nuclear physics considerations. Apart from its radiogenic component, 187 Os can be synthesized otherwise only by the s process, which means that this missing fraction can be reliably determined and subtracted by proper s-process modeling. On the other hand, 187 Re is almost completely produced by the r process. The only information needed for the interpretation as a cosmic clock is the production rate of 187 Re as a function of time. The accuracy of the s-process calculations that are needed to determine the nucleosynthetic abundance of 187 Os depends on the quality of the neutron capture cross sections averaged over the thermal neutron spectrum at the s-process sites. Laboratory measurements of these cross sections have to be corrected for the effect of nuclear levels, which can be significantly populated at the high stellar temperatures during the s process. The neutron capture cross sections of 186 Os, 187 Os and 188 Os have been measured at the CERN n TOF facility in the range between 0.7 eV and 1 MeV. From these data, Maxwellian averaged cross sections have been determined for thermal energies from 5 to 100 keV with an accuracy around 4%, 3%, and 5% for 186 Os, 187 Os, and 188 Os, respectively. Since, the first excited state in 187 Os occurs at 9.75 keV, the cross section of this isotope requires a substantial correction for thermal population of low lying nuclear levels. This effect has been evaluated on the basis of resonance data derived in the (n, γ) experiments and by an improved measurements of the inelastic scattering cross section for

  18. Re/Os cosmochronometer: measurement of neutron cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Mosconi, M.

    2007-12-21

    This experimental work is devoted to the improved assessment of the Re/Os cosmochronometer. The dating technique is based on the decay of {sup 187}Re (t{sub 1/2}=41.2 Gyr) into {sup 187}Os and determines the age of the universe by the time of onset of nucleosynthesis. The nucleosynthesis mechanisms, which are responsible for the {sup 187}Re/{sup 187}Os pair, provide the possibility to identify the radiogenic fraction of {sup 187}Os exclusively by nuclear physics considerations. Apart from its radiogenic component, {sup 187}Os can be synthesized otherwise only by the s process, which means that this missing fraction can be reliably determined and subtracted by proper s-process modeling. On the other hand, {sup 187}Re is almost completely produced by the r process. The only information needed for the interpretation as a cosmic clock is the production rate of {sup 187}Re as a function of time. The accuracy of the s-process calculations that are needed to determine the nucleosynthetic abundance of {sup 187}Os depends on the quality of the neutron capture cross sections averaged over the thermal neutron spectrum at the s-process sites. Laboratory measurements of these cross sections have to be corrected for the effect of nuclear levels, which can be significantly populated at the high stellar temperatures during the s process. The neutron capture cross sections of {sup 186}Os, {sup 187}Os and {sup 188}Os have been measured at the CERN n TOF facility in the range between 0.7 eV and 1 MeV. From these data, Maxwellian averaged cross sections have been determined for thermal energies from 5 to 100 keV with an accuracy around 4%, 3%, and 5% for {sup 186}Os, {sup 187}Os, and {sup 188}Os, respectively. Since, the first excited state in {sup 187}Os occurs at 9.75 keV, the cross section of this isotope requires a substantial correction for thermal population of low lying nuclear levels. This effect has been evaluated on the basis of resonance data derived in the (n, {gamma

  19. Measurements of the neutron capture cross sections and incineration potentials of minor-actinides in high thermal neutron fluxes: Impact on the transmutation of nuclear wastes; Mesures des sections efficaces de capture et potentiels d'incineration des actinides mineurs dans les hauts flux de neutrons: Impact sur la transmutation des dechets

    Energy Technology Data Exchange (ETDEWEB)

    Bringer, O

    2007-10-15

    This thesis comes within the framework of minor-actinide nuclear transmutation studies. First of all, we have evaluated the impact of minor actinide nuclear data uncertainties within the cases of {sup 241}Am and {sup 237}Np incineration in three different reactor spectra: EFR (fast), GT-MHR (epithermal) and HI-HWR (thermal). The nuclear parameters which give the highest uncertainties were thus highlighted. As a result of fact, we have tried to reduce data uncertainties, in the thermal energy region, for one part of them through experimental campaigns in the moderated high intensity neutron fluxes of ILL reactor (Grenoble). These measurements were focused onto the incineration and transmutation of the americium-241, the curium-244 and the californium-249 isotopes. Finally, the values of 12 different cross sections and the {sup 241}Am isomeric branching ratio were precisely measured at thermal energy point. (author)

  20. Mechanized evaluation of neutron cross-sections

    International Nuclear Information System (INIS)

    Horsley, A.; Parker, J.B.

    1967-01-01

    The evaluation work to provide accurate and consistent neutron cross-section data for multigroup neutronics calculations is not fully exploiting the available theoretical and experimental results; this has been so particularly since the introduction of on-line data handling techniques enabled experimenters to turn out vast quantities of numbers. This situation can be radically improved only by mechanizing the evaluation processes. Systems such as the SC1SRS tape will not only largely overcome the task of collecting data but will provide speedy access to it; by using computers and graph-plotting machines to tabulate and display this data, the labour of evaluation can be very greatly reduced. With some types of cross-section there is hope that by using modern curve-fitting techniques the actual evaluation and statistical accounting of the data can be performed automatically. Some areas where automatic evaluation would seem likely to succeed are specified and a discussion of the mathematical difficulties incurred, such as the elimination of anomalous data, is given. Particularly promising is the use of splines in the mechanized evaluation of data. Splines are the mathematical analogues of the draughtsman's spline used in drawing smooth curves. Their principal properties are the excellent approximations they give to the derivatives of a function; in contrast to conventional polynomial fitting, this feature ensures good interpolation and, when required, stable extrapolation. Various methods of using splines in data graduation and the problem of marrying these methods to standard statistical procedures are examined. The results of work done at AWRE with cubic splines on the mechanized evaluation of neutron scattering total cross-section and angular distribution data are presented. (author)

  1. Neutron-induced fission cross sections

    International Nuclear Information System (INIS)

    Weigmann, H.

    1991-01-01

    In the history of fission research, neutron-induced fission has always played the most important role. The practical importance of neutron-induced fission rests upon the fact that additional neutrons are produced in the fission process, and thus a chain reaction becomes possible. The practical applications of neutron-induced fission will not be discussed in this chapter, but only the physical properties of one of its characteristics, namely (n,f) cross sections. The most important early summaries on the subject are the monograph edited by Michaudon which also deals with the practical applications, the earlier review article on fission by Michaudon, and the review by Bjornholm and Lynn, in which neutron-induced fission receives major attention. This chapter will attempt to go an intermediate way between the very detailed theoretical treatment in the latter review and the cited monograph which emphasizes the applied aspects and the techniques of fission cross-section measurements. The more recent investigations in the field will be included. Section II will survey the properties of cross sections for neutron-induced fission and also address some special aspects of the experimental methods applied in their measurement. Section Ill will deal with the formal theory of neutron-induced nuclear reactions for the resolved resonance region and the region of statistical nuclear reactions. In Section IV, the fission width, or fission transmission coefficient, will be discussed in detail. Section V will deal with the broader structures due to incompletely damped vibrational resonances, and in particular will address the special case of thorium and neighboring isotopes. Finally, Section VI will briefly discuss parity violation effects in neutron-induced fission. 74 refs., 14 figs., 3 tabs

  2. Evaluation of thermal neutron cross-sections and resonance integrals of protactinium, americium, curium, and berkelium isotopes

    International Nuclear Information System (INIS)

    Belanova, T.S.

    1994-12-01

    Data on the thermal neutron fission and capture cross-sections as well as their corresponding resonance integrals are reviewed and analysed. The data are classified according to the form of neutron spectra under investigation. The weighted mean values of the cross-sections and resonance integrals for every type of neutron spectra were adopted as evaluated data. (author). 87 refs, 2 tabs

  3. LEP vacuum chamber, cross-section

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    Cross-section of the final prototype for the LEP vacuum chamber. The elliptic main-opening is for the beam. The small channel to the left is for the cooling water, to carry away the heat deposited by the synchrotron radiation. The square channel to the right houses the Non-Evaporable Getter (NEG) pump. The chamber is made from extruded aluminium. Its outside is clad with lead, to stop the synchrotron radiation emitted by the beam. For good adherence between Pb and Al, the Al chamber was coated with a thin layer of Ni. Ni being slightly magnetic, some resulting problems had to be overcome. See also 8301153.

  4. How to extract cross sections from TDHF

    International Nuclear Information System (INIS)

    Le Tourneux, Jean

    1979-01-01

    In spite of all the recent progress in solving numerically TDHF (Time Dependent Hartree-Fock) equations for heavy-ion collisions, this method is still far from lending itself readily to the computation of cross sections, except in the case of fusion. The theory presented here is purely formal so far and would lead to fairly heavy calculations in practice. It solves the problem of channel identification in the outgoing asymptotic region of TDHF solutions. It throws a bridge between TDHF and more traditional theories of nuclear reactions, which are time-independent

  5. Hyperon magnetic moments and total cross sections

    International Nuclear Information System (INIS)

    Lipkin, H.J.

    1982-06-01

    The new data on both total cross sections and magnetic moments are simply described by beginning with the additive quark model in an SU(3) limit where all quarks behave like strange quarks and breaking both additivity and SU(3) simultaneously with an additional non-additive mechanism which affects only nonstrange quark contributions. The suggestion that strange quarks behave more simply than nonstrange may provide clues to underlying structure or dynamics. Small discrepancies in the moments are analyzed and shown to provide serious difficulties for most models if they are statistically significant. (author)

  6. Fission cross section measurements for minor actinides

    Energy Technology Data Exchange (ETDEWEB)

    Fursov, B. [IPPE, Obninsk (Russian Federation)

    1997-03-01

    The main task of this work is the measurement of fast neutron induced fission cross section for minor actinides of {sup 238}Pu, {sup 242m}Am, {sup 243,244,245,246,247,248}Cm. The task of the work is to increase the accuracy of data in MeV energy region. Basic experimental method, fissile samples, fission detectors and electronics, track detectors, alpha counting, neutron generation, fission rate measurement, corrections to the data and error analysis are presented in this paper. (author)

  7. Charge changing cross sections of relativistic uranium

    International Nuclear Information System (INIS)

    Gould, H.; Greiner, D.; Lindstrom, P.; Symons, T.J.M.; Crawford, H.; Thieberger, P.; Wegner, H.

    1984-11-01

    We report equilibrium charge state distributions of uranium at energies of 962 MeV/nucleon, 437 MeV/nucleon and 200 MeV/nucleon in low Z and high Z targets and the cross sections for U 92+ reversible U 91+ and U 91+ reversible U 90+ at 962 MeV/nucleon and 437 MeV/nucleon. Equilibrium thickness Cu targets produce approx. = 5% bare U 92+ at 200 MeV/nucleon and 85% U 92+ at 962 MeV/nucleon. 7 references, 5 figures

  8. Charge changing cross sections of relativistic uranium

    Energy Technology Data Exchange (ETDEWEB)

    Gould, H; Greiner, D; Lindstrom, P; Symons, T J.M.; Crawford, H; Thieberger, P; Wegner, H

    1985-05-15

    We report equilibrium charge state distributions of uranium at energies of 962 MeV/nucleon, 437 MeV/nucleon and 200 MeV/nucleon in low Z and high Z targets and the cross sections for U/sup 92 +/reversibleU/sup 91 +/ and U/sup 91 +/reversibleU/sup 90 +/ at 962 MeV/nucleon and 437 MeV/nucleon. Equilibrium thickness Cu targets produce approx.=5% bare U/sup 92 +/ at 200 MeV/nucleon and 85% U/sup 92 +/ at 962 MeV/nucleon.

  9. Empirical continuation of the differential cross section

    International Nuclear Information System (INIS)

    Borbely, I.

    1978-12-01

    The theoretical basis as well as the practical methods of empirical continuation of the differential cross section into the nonphysical region of the cos theta variable are discussed. The equivalence of the different methods is proved. A physical applicability condition is given and the published applications are reviewed. In many cases the correctly applied procedure turns out to provide nonsignificant or even incorrect structure information which points to the necessity for careful and statistically complete analysis of the experimental data with a physical understanding of the analysed process. (author)

  10. L-shell photoelectric cross section measurements

    Energy Technology Data Exchange (ETDEWEB)

    Arora, S K; Allawadhi, K L; Sood, B S [Punjabi Univ., Patiala (India). Nuclear Science Labs.

    1981-05-14

    L-shell photoelectric cross sections in Ta, W, Au, Pb, Th and U at 59.5 keV have been determined using three different versions of Sood's method of measuring the absolute yield of fluorescent x-rays when a target is irradiated with a known flux of photons. The results obtained by all the methods agree with one another showing that no hidden systematic errors are involved in the measurements. The present results are found to compare well with the theoretical calculations of Scofield (Lawrence Livermore Laboratory Report No 51326).

  11. The evaluated neutron cross sections and resonance integrals of fission products with Z = 57-62

    International Nuclear Information System (INIS)

    Fedorova, A.F.; Pisanko, Zh.I.; Novoselov, G.M.

    1976-01-01

    Neutron cross sections at a neutron velocity of V=2200 m/s, and resonance integrals for fission products with Z=57-71 are estimated. In obtaining the recommended values the results of the neutron cross sections and resonance integrals for elements used as references were normalized in accordance with the latest adjusted values. In the course of estimation, preference was given to the more accurate methods for obtaining the measured values and to the more recent investigations

  12. The evaluated neutron cross sections and resonance integrals of fission products with Z=63-71

    International Nuclear Information System (INIS)

    Fedorova, A.F.; Pisanko, Zh.I.; Novoselov, G.M.

    1976-01-01

    Neutron cross sections at a neutron velocity of V=2200 m/s, and the resonance integrals for fission products with Z=63-71 are estimated. In obtaining the recommended values the results were normalized of the neutron cross sections and resonance integrals for elements used as references in accordance with the latest adjusted values. In the course of estimation, preference was given to the more accurate measuring methods and the more recent investigations. Scientific publications up to 1975 have been used

  13. Cross sections, benchmarks, etc.: What is data testing all about

    International Nuclear Information System (INIS)

    Wagschal, J.; Yeivin, Y.

    1985-01-01

    In order to determine the consistency of two distinct measurements of a physical quantity, the discrepancy d between the two should be compared with its own standard deviation, σ = √(σ/sub 1//sup 2/+σ/sub 2//sup 2/). To properly test a given cross-section library by a set of benchmark (integral) measurements, the quantity corresponding to (d/σ)/sup 2/ is the quadratic d/sup dagger/C/sup -1/d. Here d is the vector of which the components are the discrepancies between the calculated values of the integral parameters and their corresponding measured values, and C is the uncertainty matrix of these discrepancies. This quadratic form is the only true measure of the joint consistency of the library and benchmarks. On the other hand, the very matrix C is essentially all one needs to adjust the library by the benchmarks. Therefore, any argument against adjustment simultaneously disqualifies all serious attempts to test cross-section libraries against integral benchmarks

  14. Neutron cross section measurements using the ORELA: the stable tellurium isotopes (n,γ), 238U(n,n'), 232Th(n,n'), 187Os(n,n'), 186187188Os(n,nn'γ), and 205Tl(n,nγ). Progress report, September 1, 1980-September 1, 1981

    International Nuclear Information System (INIS)

    Winters, R.R.

    1981-08-01

    Progress on the following subjects is reviewed: (1) high resolution neutron cross sections and the optical model potential, (2) renormalization of neutron capture cross sections, and (3) measurement of the argon 40 total cross section

  15. ZZ SNLRML, Dosimetry Cross-Section Recommendations

    International Nuclear Information System (INIS)

    1996-01-01

    Description of program or function: Format: SAND-II; Number of groups: 640 group SAND-II group structure. Nuclides: Cd, B, Au, S, Ni, Li, F, Na, Mg, Al, Si, P, Sc, Ti, Mn, Fe, Co, Cu, Zn, Zr, Nb, Mo, Rh, Ag, In, I, Th, U, Np, Pu, Am. Origin: ENDF/B-VI, ENDF/B-V, IRDF-90, JENDL-3, JEF 2.2 and GLUCS data with special modifications from private communications. Weighting spectrum: flat. SNLRML is a reactor dosimetry library that draws upon all available evaluated cross section libraries and selects the best evaluation for application to research reactor spectrum determinations. Many of the components of the SNLRML come from the ENDF/B-VI and IRDF-90 (DLC-0161) libraries. The library format was selected for easy interface with spectrum determination codes such as SAND-II (CCC-0112 and LSL-M2 (PSR-233) and the new PSR-0345/SNL/SAND-II has been enhanced to interface with SNLRML. The data is recommended for spectrum determination applications and for the prediction of neutron activation of typical radiation sensor materials. The library has been tested for consistency of the cross section in wide variety of neutron environments. The results and cautions from this testing have been documented. The data has been interfaced with radiation transport codes, such as TWODANT-SYS (CCC-0547) and MCNP (CCC-0200), in order to compare calculated and measured activities for benchmark reactor experiments

  16. Pion production cross sections and associated parameters

    International Nuclear Information System (INIS)

    Bradbury, J.N.

    1985-01-01

    Negative pions have been used for radiotherapy at the meson factories LAMPF (USA), SIN (Switzerland), and TRIUMF (Canada) and have been planned for use at new meson facilities under construction (USSR) and at proposed dedicated medical facilities. Providing therapeutically useful dose rates of pions requires a knowledge of the pion production cross sections as a function of primary proton energy (500 to 1000 MeV), pion energy (less than or equal to100 MeV), production angle, and target material. The current status of the data base in this area is presented including theoretical guidelines for extrapolation purposes. The target material and geometry, as well as the proton and pion beam parameters, will affect the electron (and muon) contamination in the beam which may have an important effect on both the LET characteristics of the dose and the dose distribution. In addition to cross-section data, channel characteristics such as length of pion trajectory, solid-angle acceptance, and momentum analysis will affect dose rate, distribution, and quality. Such considerations are briefly addressed in terms of existing facilities and proposed systems. 16 refs., 6 figs

  17. Total neutron cross section for 181Ta

    Directory of Open Access Journals (Sweden)

    Schilling K.-D.

    2010-10-01

    Full Text Available The neutron time of flight facility nELBE, produces fast neutrons in the energy range from 0.1 MeV to 10 MeV by impinging a pulsed relativistic electron beam on a liquid lead circuit [1]. The short beam pulses (∼10 ps and a small radiator volume give an energy resolution better than 1% at 1 MeV using a short flight path of about 6 m, for neutron TOF measurements. The present neutron source provides 2 ⋅ 104  n/cm2s at the target position using an electron charge of 77 pC and 100 kHz pulse repetition rate. This neutron intensity enables to measure neutron total cross section with a 2%–5% statistical uncertainty within a few days. In February 2008, neutron radiator, plastic detector [2] and data acquisition system were tested by measurements of the neutron total cross section for 181Ta and 27Al. Measurement of 181Ta was chosen because lack of high quality data in an anergy region below 700 keV. The total neutron cross – section for 27Al was measured as a control target, since there exists data for 27Al with high resolution and low statistical error [3].

  18. Atlas of photoneutron cross sections obtained with monoenergetic photons

    International Nuclear Information System (INIS)

    Dietrich, S.S.; Berman, B.L.

    1988-01-01

    Photoneutron cross-section and integrated cross-section data obtained with monoenergetic photons are presented in a uniform format. All of the measured partial photoneutron cross sections, the total photoneutron cross section, and the photoneutron yield cross section are plotted as functions of the incident photon energy, as are the integrated photoneutron cross sections and their first and second moments. The values of the integrated cross sections and the moments of the integrated total cross section up to the highest photon energy for which they were measured are tabulated, as are the parameters of Lorentz curves fitted to the total photoneutron cross-section data for medium and heavy nuclei (A>50). This compilation is current as of June 1987. copyright 1988 Academic Press, Inc

  19. Neutron-induced cross sections of short-lived nuclei via the surrogate reaction method

    Directory of Open Access Journals (Sweden)

    Morel P.

    2011-10-01

    Full Text Available The measurement of neutron-induced cross sections of short-lived nuclei is extremely difficult due to the radioactivity of the samples. The surrogate reaction method is an indirect way of determining cross sections for nuclear reactions that proceed through a compound nucleus. This method presents the advantage that the target material can be stable or less radioactive than the material required for a neutron-induced measurement. We have successfully used the surrogate reaction method to extract neutron-induced fission cross sections of various short-lived actinides. In this work, we investigate whether this technique can be used to determine neutron-induced capture cross sections in the rare-earth region.

  20. Neutron-induced cross sections of short-lived nuclei via the surrogate reaction method

    Directory of Open Access Journals (Sweden)

    Tassan-Got L.

    2012-02-01

    Full Text Available The measurement of neutron-induced cross sections of short-lived nuclei is extremely difficult due to the radioactivity of the samples. The surrogate reaction method is an indirect way of determining cross sections for nuclear reactions that proceed through a compound nucleus. This method presents the advantage that the target material can be stable or less radioactive than the material required for a neutron-induced measurement. We have successfully used the surrogate reaction method to extract neutron-induced fission cross sections of various short-lived actinides. In this work, we investigate whether this technique can be used to determine neutron-induced capture cross sections in the rare-earth region.

  1. Determination of minor actinides fission cross sections by means of transfer reactions

    Energy Technology Data Exchange (ETDEWEB)

    Jurado, B.; Aiche, M.; Barreau, G.; Boyer, S.; Czajkowski, S.; Dassie, D.; Grosjean, C.; Guiral, A.; Haas, B.; Osmanov, B.; Petit, M. [CENBG - UMR 5795 CNRS/IN2P3-Univ. Bordeaux 1- Le Haut Vigneau, 33175 Gradignan (France); Berthoumieux, E.; Gunsing, F.; Perrot, L.; Theisen, Ch. [CEN Saclay, DSM/DAPNIA/SPhN, 91191 Gif-sur-Yvette cedex (France); Bauge, E. [CEA, SPhN, BP12 91680 Bruyeres-le-Chatel (France); Michel-Sendis, F. [IPN, 15 rue G. Clemenceau, 91406 Orsay cedex (France); Billebaud, A. [LPSC, 53 Avenue des Martyrs, 38026 Grenoble cedex (France); Wilson, J. N. [IPN, 15 rue G. Clemenceau, 91406 Orsay cedex (France); LPSC, 53 Avenue des Martyrs, 38026 Grenoble cedex (France); Ahmad, I.; Greene, J.P.; Janssens, R. V. F. [ANL, 9700 S. Cass Avenue, Argonne, IL 60439 (United States)

    2005-07-01

    We present an original method that allows to determine neutron-induced cross sections of very short-lived minor actinides. This indirect method, based on the use of transfer reactions, has already been applied with success for the determination of the neutron-induced fission and capture cross section of {sup 233}Pa, a key nucleus in the {sup 232}Th - {sup 233}U fuel cycle. A recent experiment using this technique has been performed to determine the neutron-induced fission cross sections of {sup 242,243,244}Cm and {sup 241}Am which are present in the nuclear waste of the current U-Pu fuel cycle. These cross sections are highly relevant for the design of reactors capable to incinerate minor actinides. The first results will be illustrated. (authors)

  2. Evaluation of neutron and gamma-ray-production cross-section data for lead

    International Nuclear Information System (INIS)

    Fu, C.Y.; Perey, F.G.

    1975-01-01

    A survey was made of the available information on neutron and gamma-ray-production cross-section measurements of lead. From these and from relevant nuclear-structure information on the Pb isotopes, recommended neutron cross-section data sets for lead covering the neutron energy range from 0.00001 eV to 20.0 MeV have been prepared. The cross sections are derived from experimental results available to February 1972 and from calculations based on optical-model, DWBA, and Hauser--Feshbach theories. Comparisons which show good agreement between theoretical and experimental values are displayed in a number of graphs. Also presented graphically are smoothed total cross sections, Legendre coefficients for angular distributions, and a representative energy distribution of gamma rays from resonance capture. 15 tables, 36 figures, 104 references

  3. The 139La(n,gamma) cross section: key for the onset of the s process

    CERN Document Server

    Terlizzi, R.; Aerts, G.; Alvarez, H.; Alvarez-Velarde, F.; Andriamonje, S.; Andrzejewski, J.; Assimakopoulos, P.; Audouin, L.; Badurek, G.; Baumann, P.; Becvar, F.; Berthoumieux, E.; Calviani, M.; Calvino, F.; Cano-Ott, D.; Capote, R.; de Albornoz, A.Carrillo; Cennini, P.; Chepel, V.; Chiaveri, E.; Colonna, N.; Cortes, G.; Couture, A.; Cox, J.; Dahlfors, M.; David, S.; Dillmann, I.; Dolfini, R.; Domingo-Pardo, C.; Dridi, W.; Duran, I.; Eleftheriadis, C.; Embid-Segura, M.; Ferrant, L.; Ferrari, A.; Ferreira-Marques, R.; Fitzpatrick, L.; Frais-Koelbl, H.; Fujii, K.; Furman, W.; Gallino, R.; Goncalves, I.; Gonzalez-Romero, E.; Goverdovski, A.; Gramegna, F.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Haas, B.; Haight, R.; Heil, M.; Herrera-Martinez, A.; Igashira, M.; Isaev, S.; Jericha, E.; Kadi, Y.; Kappeler, F.; Karamanis, D.; Karadimos, D.; Kerveno, M.; Ketlerov, V.; Koehler, P.; Konovalov, V.; Kossionides, E.; Krticka, M.; Lamboudis, C.; Leeb, H.; Lindote, A.; Lopes, I.; Lozano, M.; Lukic, S.; Marganiec, J.; Marques, L.; Marrone, S.; Massimi, C.; Mastinu, P.; Mengoni, A.; Milazzo, P.M.; Moreau, C.; Mosconi, M.; Neves, F.; Oberhummer, H.; O'Brien, S.; Pancin, J.; Papachristodoulou, C.; Papadopoulos, C.; Paradela, C.; Patronis, N.; Pavlik, A.; Pavlopoulos, P.; Perrot, L.; Pignatari, M.; Plag, R.; Plompen, A.; Plukis, A.; Poch, A.; Pretel, C.; Quesada, J.; Rauscher, T.; Reifarth, R.; Rosetti, M.; Rubbia, C.; Rudolf, G.; Rullhusen, P.; Salgado, J.; Sarchiapone, L.; Savvidis, I.; Stephan, C.; Tagliente, G.; Tain, J.L.; Tassan-Got, L.; Tavora, L.; Vannini, G.; Vaz, P.; Ventura, A.; Villamarin, D.; Vincente, M.C.; Vlachoudis, V.; Vlastou, R.; Voss, F.; Walter, S.; Wendler, H.; Wiescher, M.; Wisshak, K.

    2007-01-01

    The nuclear resonance parameters and the capture cross section of the neutron magic isotope 139La has been measured n_TOF. The description of the experimental apparata is followed by the data analysis procedures. We extracted the resonance parameters, the main nuclear quantities such as the resonance integral, the average gamma widths for s- and p-waves, the nuclear level densities and the neutron strength functions. These results represent a signifcant improvement over previous data. The deduced Maxwellian-averaged capture cross sections are important for the interpretation of the most recent spectroscopic observations in low metallicity stars.

  4. Review of the microscopic cross sections for the americium isotopes in the resolved resonance region

    International Nuclear Information System (INIS)

    Browne, J.C.

    1978-01-01

    The differential cross section measurements for 241 Am, /sup 242m/Am and 243 Am are reviewed in the energy range from 0.5 eV to 10 keV. Parameters extracted from resonance analysis, such as the neutron strength function, the average level spacing, the average capture and fission widths, are compared for the various measurements. The average capture and fission cross sections from 100 eV to 10 keV are directly compared. The status of the data set is discussed with suggestions for further measurements. 24 references

  5. Preliminary study of the {alpha} ratio measurement, ratio of the neutron capture cross section to the fission one for {sup 233}U, on the PEREN platform. Development and study of the experimental setup; Etude preliminaire de la mesure du rapport {alpha}, rapport de la section efficace moyenne de capture sur celle de fission de l'{sup 233}U, sur la plateforme PEREN. Developpement et etude du dispositif experimental

    Energy Technology Data Exchange (ETDEWEB)

    Cognet, M A

    2007-12-15

    Producing nuclear energy in order to reduce anthropic CO{sub 2} emission and to meet high energy demand, implies three conditions to the nuclear plants of the IV. generation: safety improvements, radioactive waste minimization, and fuel breeding for a sustainable use of the resources. The Thorium fuel cycle used in Molten Salt Reactors seems promising. Many numerical studies based on probabilistic codes are carried out in order to analyse the behaviour of such reactors. Nevertheless, one of the most important parameters is badly known: the alpha ratio of {sup 233}U, ratio of the neutron capture cross section to fission one for {sup 233}U. This key-parameter is necessary to calculate the breeding ratio and thus, the deployment capacities of those reactors. This Ph-D thesis was intended to prepare a precise measurement of the alpha ratio of {sup 233}U between 1 eV and 10 keV. Preliminary measurements have been performed on the experimental platform PEREN. This experimental environment is composed of a lead slowing-down time spectrometer associated with an intense pulsed neutron generator. Capture and fission rates are measured thanks to eight scintillators with their photomultipliers, surrounding a fission chamber. A software analysis sets the coincidence rate between the scintillators. In order to understand perfectly the experimental setup, preliminary tests using a {sup 235}U fission chamber have been done. This experiment resulted in a very low signal to background ratio (1 %). The background coming from the scintillators themselves seriously handicapped the measurement. Another series of experiment has been done with scintillators 5 times thinner. Nevertheless, the signal to background ratio should still be increased to measure the capture of {sup 235}U. To make sure that the experimental setup has totally been understood, we made many comparisons between experimental results and simulations. Two simulation codes were mainly used: MCNP and GEANT4. We paid

  6. Preliminary study of the {alpha} ratio measurement, ratio of the neutron capture cross section to the fission one for {sup 233}U, on the PEREN platform. Development and study of the experimental setup; Etude preliminaire de la mesure du rapport {alpha}, rapport de la section efficace moyenne de capture sur celle de fission de l'{sup 233}U, sur la plateforme PEREN. Developpement et etude du dispositif experimental

    Energy Technology Data Exchange (ETDEWEB)

    Cognet, M.A

    2007-12-15

    Producing nuclear energy in order to reduce anthropic CO{sub 2} emission and to meet high energy demand, implies three conditions to the nuclear plants of the IV. generation: safety improvements, radioactive waste minimization, and fuel breeding for a sustainable use of the resources. The Thorium fuel cycle used in Molten Salt Reactors seems promising. Many numerical studies based on probabilistic codes are carried out in order to analyse the behaviour of such reactors. Nevertheless, one of the most important parameters is badly known: the alpha ratio of {sup 233}U, ratio of the neutron capture cross section to fission one for {sup 233}U. This key-parameter is necessary to calculate the breeding ratio and thus, the deployment capacities of those reactors. This Ph-D thesis was intended to prepare a precise measurement of the alpha ratio of {sup 233}U between 1 eV and 10 keV. Preliminary measurements have been performed on the experimental platform PEREN. This experimental environment is composed of a lead slowing-down time spectrometer associated with an intense pulsed neutron generator. Capture and fission rates are measured thanks to eight scintillators with their photomultipliers, surrounding a fission chamber. A software analysis sets the coincidence rate between the scintillators. In order to understand perfectly the experimental setup, preliminary tests using a {sup 235}U fission chamber have been done. This experiment resulted in a very low signal to background ratio (1 %). The background coming from the scintillators themselves seriously handicapped the measurement. Another series of experiment has been done with scintillators 5 times thinner. Nevertheless, the signal to background ratio should still be increased to measure the capture of {sup 235}U. To make sure that the experimental setup has totally been understood, we made many comparisons between experimental results and simulations. Two simulation codes were mainly used: MCNP and GEANT4. We paid

  7. 180Ta/sup g,m/ production cross sections form the 180Hf(p,n) reaction

    International Nuclear Information System (INIS)

    Norman, E.B.; Renner, T.R.; Grant, P.J.

    1981-01-01

    Cross sections have been determined for the production of the J/sup π/ = 1 + 180 Ta/sup g/ and the J/sup π/= 9 - 180 Ta/sup m/ from the 180 Hf(p,n) reaction. The 180 Ta/sup g/ cross sections were determined from measurements of γ-rays emitted following the electron-capture and β-decay of this 8.1-hour state. Total 180 Ta production cross sections were determined from measurements of the thick-target (p,n) yield. 180 Ta/sup m/ cross sections were calculated by subtracting the 180 Ta/sup g/ cross sections from the total (p,n) cross sections. These measurements are compared with the results of a statistical-model evaporation calculation

  8. Differences between LASL- and ANL-processed cross sections

    International Nuclear Information System (INIS)

    Kidman, R.B.; MacFarlane, R.E.; Becker, M.

    1978-03-01

    As part of the Los Alamos Scientific Laboratory (LASL) cross-section processing development, LASL cross sections and results from MINX/1DX system are compared to the Argonne National Laboratory cross sections and results from the ETOE-2/MC 2 -2 system for a simple reactor problem. Exact perturbation theory is used to establish the eigenvalue effect of every isotope group cross-section difference. Cross sections, cross-section differences, and their eigenvalue effects are clearly and conveniently displayed and compared on a group-by-group basis

  9. Cross section homogenization analysis for a simplified Candu reactor

    International Nuclear Information System (INIS)

    Pounders, Justin; Rahnema, Farzad; Mosher, Scott; Serghiuta, Dumitru; Turinsky, Paul; Sarsour, Hisham

    2008-01-01

    The effect of using zero current (infinite medium) boundary conditions to generate bundle homogenized cross sections for a stylized half-core Candu reactor problem is examined. Homogenized cross section from infinite medium lattice calculations are compared with cross sections homogenized using the exact flux from the reference core environment. The impact of these cross section differences is quantified by generating nodal diffusion theory solutions with both sets of cross sections. It is shown that the infinite medium spatial approximation is not negligible, and that ignoring the impact of the heterogeneous core environment on cross section homogenization leads to increased errors, particularly near control elements and the core periphery. (authors)

  10. Total cross sections for pion charge exchange on the proton

    International Nuclear Information System (INIS)

    Breitschopf, J.

    2006-01-01

    This work describes the measurement of total SCX cross sections employing a new 4π scintillation counter to perform transmission measurements in the incident pion energy range from about 38 to 250 MeV. A small 4π detector box consisting of thin plastic scintillators has been constructed. The transmission technique, which was used, relates the number of transmitted charged pions to that of incident beam pions and this way effectively counts events with neutral products. The incoming negative pions were counted by three beam defining counters before they hit a target of very well known size and chemical composition. The target was placed in the box detector which was not sensitive to the neutral particles resulting from the SCX. The total cross section for emerging neutral particles was derived from the comparison of the numbers of the incoming and transmitted charged particles. The total SCX cross section on hydrogen was derived from the transmissions of a CH 2 target, a carbon target and an empty target. For a detailed offline analysis all TDC, QDC and FADC information was recorded in an event by event mode for each triggered beam event. Various corrections had to be applied to the data, such as random correction, the detection of neutrals in the detector, Dalitz decay, pion decay and the radiative pion capture. This measurement covers, as the only experiment, the whole Δ-resonance and the sp-interference region in one single experimental setup and improves the available data base for the SCX reaction. It is shown that the description of the SCX cross sections is improved if the s-wave amplitudes, that have been fixed essentially by elastic pion-nucleon scattering data, is reduced by (4±1.5)%. The exact value depends on the SCX literature data included and on the parameters of the Δ 0 Breit-Wigner resonance describing the p 33 -waves. This shows that p-wave as well as s-wave effects should be considered in studies of isospin symmetry breaking. Interestingly

  11. Total cross sections for pion charge exchange on the proton

    Energy Technology Data Exchange (ETDEWEB)

    Breitschopf, J.

    2006-04-28

    This work describes the measurement of total SCX cross sections employing a new 4{pi} scintillation counter to perform transmission measurements in the incident pion energy range from about 38 to 250 MeV. A small 4{pi} detector box consisting of thin plastic scintillators has been constructed. The transmission technique, which was used, relates the number of transmitted charged pions to that of incident beam pions and this way effectively counts events with neutral products. The incoming negative pions were counted by three beam defining counters before they hit a target of very well known size and chemical composition. The target was placed in the box detector which was not sensitive to the neutral particles resulting from the SCX. The total cross section for emerging neutral particles was derived from the comparison of the numbers of the incoming and transmitted charged particles. The total SCX cross section on hydrogen was derived from the transmissions of a CH{sub 2} target, a carbon target and an empty target. For a detailed offline analysis all TDC, QDC and FADC information was recorded in an event by event mode for each triggered beam event. Various corrections had to be applied to the data, such as random correction, the detection of neutrals in the detector, Dalitz decay, pion decay and the radiative pion capture. This measurement covers, as the only experiment, the whole {delta}-resonance and the sp-interference region in one single experimental setup and improves the available data base for the SCX reaction. It is shown that the description of the SCX cross sections is improved if the s-wave amplitudes, that have been fixed essentially by elastic pion-nucleon scattering data, is reduced by (4{+-}1.5)%. The exact value depends on the SCX literature data included and on the parameters of the {delta}{sup 0} Breit-Wigner resonance describing the p{sub 33}-waves. This shows that p-wave as well as s-wave effects should be considered in studies of isospin

  12. Cross sections of electron loss and capture for beams of O{sup +} in water vapor from the energy range of 0,2 to 1,2 MeV; Secoes de choque de perda e captura eletronica para feixes de O{sup +} em vapor de agua em uma faixa de energia entre 0,2 e 1,2 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Vitor Jesus de

    2015-06-01

    The study of the interactions between atoms and molecules is important for the knowledge of the cross sections of the processes that contribute to the deposition of energy by charged particle beams used in radiotherapy planning and transport particle simulation codes. Heavy ions, such as oxygen, induce many cellular and molecular damages in human cells.as a result of interaction between the projectile and atoms and molecules. The use of proton and carbon as the projectile interacting with water molecules is well characterized, however there are few studies with oxygen ions. In this work we are interested in the study of electron loss (projectile ionization) and electron capture with charge state 1+. The Pelletron accelerator of 1.7 MeV from the Federal University of Rio de Janeiro housed in the Atomic and Molecular collisions Laboratory (LACAM) has been used, which can accelerate atomic and molecular ions up to speeds of the order of hundredths of light speed, and consists of the source of negative ions, the Wien filter, the accelerator itself and the magnet load selector. The detection device used to evaluate the processes of interaction (capture and loss) between the beam of the O{sup +} and the water molecule is a Microchannel Plate (MCP) at the position sensitive anode. The collisions of O{sup +} beans are being studied in the range of 0.2 to 1.2 MeV with water vapor (Z = 10). Were obtained the respective absolute cross sections for electron loss and electron capture and compared with the cross sections of the molecule methane (CH4 → Z = 10), the isoelectronic water molecule. The experimental results show an agreement between the measurements with water and methane. Comparisons were made with results of theoretical models for electron loss using the 'Free Collision Model' and for capture the Bohr and Lindhard model. The theoretical results for electron loss show an agreement of experimental data with the model used. The model of Bohr and Lindhard

  13. Formulation and Analysis of the Quantum Radar Cross Section

    Science.gov (United States)

    Brandsema, Matthew J.

    In radar, the amount of returns that an object sends back to the receiver after being struck by an electromagnetic wave is characterized by what is known as the radar cross section, denoted by sigma typically. There are many mechanisms that affect how much radiation is reflected back in the receiver direction, such as reflectivity, physical contours and dimensions, attenuation properties of the materials, projected cross sectional area and so on. All of these characteristics are lumped together in a single value of sigma, which has units of m2. Stealth aircrafts for example are designed to minimize its radar cross section and return the smallest amount of radiation possible in the receiver direction. A new concept has been introduced called quantum radar, that uses correlated quantum states of photons as well as the unique properties of quantum mechanics to ascertain information on a target at a distance. At the time of writing this dissertation, quantum radar is very much in its infancy. There still exist fundamental questions about the feasibility of its implementation, especially in the microwave spectrum. However, what has been theoretically determined, is that quantum radar has a fundamental advantage over classical radar in terms of resolution and returns in certain regimes. Analogous to the classical radar cross section (CRCS), the concept of the quantum radar cross section (QRCS) has been introduced. This quantity measures how an object looks to a quantum radar be describing how a single photon, or small cluster of photons scatter off of a macroscopic target. Preliminary simulations of the basic quantum radar cross section equation have yielded promising results showing an advantage in sidelobe response in comparison to the classical RCS. This document expands upon this idea by providing insight as to where this advantage originates, as well as developing more rigorous simulation analysis, and greatly expanding upon the theory. The expanded theory presented

  14. K sup + nucleus total cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Sawafta, R.

    1990-01-01

    The scattering of K{sup +} mesons from nuclei has attracted considerable interest in the last few years. The K{sup +} holds a very special position as the weakest of all strongly interaction probes. The average cross section is not larger than about 10 mb at lab momenta below 800 MeV/c, corresponding to a mean free path in the nucleus larger than 5 fm. Thus the K{sup +} is capable of probing the entire volume of the nucleus. Single scattering of the K{sup +} with a nucleon in the nucleus dominates the nuclear scattering, and only small and calculable higher order corrections are needed. The nucleon is a dynamical entity and its internal structure can, in principle, be altered by its surrounding nuclear environment. This work reports an experiment in which the K{sup +} is used to compare the nucleon in the nucleus with a free nucleon.

  15. Differential cross section of atomic hydrogen photoionization

    International Nuclear Information System (INIS)

    Kondratovich, V.D.; Ostrovskij, V.N.

    1986-01-01

    Differential cross-section of atomic hydrogen photoeffect in external electric field was investigated in semiclassical approximation. Interference was described. It occurred due to the fact that infinite number of photoelectron trajectories leads to any point of classically accessible motion region. Interference picture can reach macroscopic sizes. The picture is determined by location of function nodes, describing finite electron motion along one of parabolic coordinates. The squares of external picture rings are determined only by electric field intensity in the general case at rather high energies. Quantum expression for photocurrent density was obtained using Green function in superposition of Coulomb and uniform field as well as semiclassical approximation. Possible applications of macroscopic interference picture to specification of atom ionization potentials, selective detection of atoms or particular molecules, as well as weak magnetic field and observation of Aaronov-Bom effect are discussed

  16. Angle-averaged Compton cross sections

    International Nuclear Information System (INIS)

    Nickel, G.H.

    1983-01-01

    The scattering of a photon by an individual free electron is characterized by six quantities: α = initial photon energy in units of m 0 c 2 ; α/sub s/ = scattered photon energy in units of m 0 c 2 ; β = initial electron velocity in units of c; phi = angle between photon direction and electron direction in the laboratory frame (LF); theta = polar angle change due to Compton scattering, measured in the electron rest frame (ERF); and tau = azimuthal angle change in the ERF. We present an analytic expression for the average of the Compton cross section over phi, theta, and tau. The lowest order approximation to this equation is reasonably accurate for photons and electrons with energies of many keV

  17. Plasma-based radar cross section reduction

    CERN Document Server

    Singh, Hema; Jha, Rakesh Mohan

    2016-01-01

    This book presents a comprehensive review of plasma-based stealth, covering the basics, methods, parametric analysis, and challenges towards the realization of the idea. The concealment of aircraft from radar sources, or stealth, is achieved through shaping, radar absorbing coatings, engineered materials, or plasma, etc. Plasma-based stealth is a radar cross section (RCS) reduction technique associated with the reflection and absorption of incident electromagnetic (EM) waves by the plasma layer surrounding the structure. A plasma cloud covering the aircraft may give rise to other signatures such as thermal, acoustic, infrared, or visual. Thus it is a matter of concern that the RCS reduction by plasma enhances its detectability due to other signatures. This needs a careful approach towards the plasma generation and its EM wave interaction. The book starts with the basics of EM wave interactions with plasma, briefly discuss the methods used to analyze the propagation characteristics of plasma, and its generatio...

  18. ISSUES IN NEUTRON CROSS SECTION COVARIANCES

    Energy Technology Data Exchange (ETDEWEB)

    Mattoon, C.M.; Oblozinsky,P.

    2010-04-30

    We review neutron cross section covariances in both the resonance and fast neutron regions with the goal to identify existing issues in evaluation methods and their impact on covariances. We also outline ideas for suitable covariance quality assurance procedures.We show that the topic of covariance data remains controversial, the evaluation methodologies are not fully established and covariances produced by different approaches have unacceptable spread. The main controversy is in very low uncertainties generated by rigorous evaluation methods and much larger uncertainties based on simple estimates from experimental data. Since the evaluators tend to trust the former, while the users tend to trust the latter, this controversy has considerable practical implications. Dedicated effort is needed to arrive at covariance evaluation methods that would resolve this issue and produce results accepted internationally both by evaluators and users.

  19. Partial cross sections in H- photodetachment

    International Nuclear Information System (INIS)

    Halka, M.

    1993-04-01

    This dissertation reports experimental measurements of partial decay cross sections in the H - photodetachment spectrum. Observed decays of the 1 P 0 H -** (n) doubly-excitedresonances to the H(N=2) continuum are reported for n=2,3, and 4 from 1990 runs in which the author participated. A recent analysis of 1989 data revealing effects of static electric fields on the partial decay spectrum above 13.5 eV is also presented. The experiments were performed at the High Resolution Atomic Beam Facility. the Los Alamos Meson Physics Facility, with a relativistic H - beam (β=0.842)intersecting a ND:YAG laser. Variation of the intersection angle amounts to Doppler-shifting the photon energy, allowing continuous tuning of the laser energy as viewed from the moving ions' frame

  20. Angle-averaged Compton cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Nickel, G.H.

    1983-01-01

    The scattering of a photon by an individual free electron is characterized by six quantities: ..cap alpha.. = initial photon energy in units of m/sub 0/c/sup 2/; ..cap alpha../sub s/ = scattered photon energy in units of m/sub 0/c/sup 2/; ..beta.. = initial electron velocity in units of c; phi = angle between photon direction and electron direction in the laboratory frame (LF); theta = polar angle change due to Compton scattering, measured in the electron rest frame (ERF); and tau = azimuthal angle change in the ERF. We present an analytic expression for the average of the Compton cross section over phi, theta, and tau. The lowest order approximation to this equation is reasonably accurate for photons and electrons with energies of many keV.

  1. Sudakov resummation of multiparton QCD cross sections

    CERN Document Server

    Bonciani, R; Mangano, Michelangelo L; Nason, P

    2003-01-01

    We present the general expressions for the resummation, up to next-to-leading logarithmic accuracy, of Sudakov-type logarithms in processes with an arbirtrary number of hard-scattering partons. These results document the formulae used by the authors in several previous phenomenological studies. The resummation formulae presented here, which are valid for phase-space factorizable observables, determine the resummation correction in a process-independent fashion. All process dependence is encoded in the colour and flavour structure of the leading order and virtual one-loop amplitudes, and in Sudakov weights associated to the cross section kinematics. We explicitly illustrate the application to the case of Drell--Yan and prompt-photon production.

  2. Sudakov resummation of multiparton QCD cross sections

    International Nuclear Information System (INIS)

    Bonciani, Roberto; Catani, Stefano; Mangano, Michelangelo L.; Nason, Paolo

    2003-01-01

    We present the general expressions for the resummation, up to next-to-leading logarithmic accuracy, of Sudakov-type logarithms in processes with an arbitrary number of hard-scattering partons. These results document the formulae used by the authors in several previous phenomenological studies. The resummation formulae presented here, which are valid for phase-space factorizable observables, determine the resummation correction in a process-independent fashion. All process dependence is encoded in the colour and flavour structure of the leading order and virtual one-loop amplitudes, and in Sudakov weights associated to the cross section kinematics. We explicitly illustrate the application to the case of Drell-Yan and prompt-photon production

  3. Electroweak Boson Cross-Section Measurements

    CERN Document Server

    The ATLAS collaboration

    2009-01-01

    This report summarises the ATLAS prospects for the measurement of W and Z pro- duction cross-section at the LHC. The electron and muon decay channels are considered. Focusing on the early data taking phase, strategies are presented that allow a fast and robust extraction of the signals. An overall uncertainty of about 5% can be achieved with 50 pb−1 in the W channels, where the background uncertainty dominates (the luminosity measurement uncertainty is not discussed here). In the Z channels, the expected preci- sion is 3%, the main contribution coming from the lepton selection efficiency uncertainty. Extrapolating to 1 fb−1 , the uncertainties shrink to incompressible values of 1-2%, de- pending on the final state. This irreducible uncertainty is essentially driven by strong interaction effects, notably parton distribution uncertainties and non-perturbative effects, affecting the W and Z rapidity and transverse momentum distributions. These effects can be constrained by measuring these distributions. Al...

  4. Reaction cross section for Ne isotopes

    International Nuclear Information System (INIS)

    Panda, R.N.; Sahu, B.K.; Patra, S.K.

    2012-01-01

    In the present contribution, first the bulk properties are calculated, such as binding energy (BE), root mean square charge radius r ch , matter radius r m and quadrupole deformation parameter β 2 for 18-32 Ne isotopes in the Relativistic mean field (RMF) and effective field theory motivated RMF (E-RMF) formalisms . Then the total nuclear reaction cross section σR is analyzes for the scattering of 20 Ne and 28-32 Ne from a 12 C target at 240 MeV/nucleon by using the RMF model. Thus the objective of the present study is to calculate the bulk properties as well as a systematic analysis of σR over a range of neutron rich nuclei in the frame work of Glauber model

  5. Topological supersymmetric structure of hadron cross sections

    International Nuclear Information System (INIS)

    Gauron, P.; Nicolescu, B.; Ouvry, S.

    1980-12-01

    Recently a way of fully implementing unitarity in the framework of a Dual Topological Unitarization theory, including not only mesons but also baryons, was found. This theory consists in the topological description of hadron interactions involving confined quarks in terms of two 2-dimensional surfaces (a closed 'quantum' surface and a bounded 'classical' surface). We show that this description directly leads, at the zeroth order of the topological expansion, to certain relations between hadron cross-sections, in nice agreement with experimental data. A new topological suppression mechanism is shown to play an important dynamical role. We also point out a new topological supersymmetry property, which leads to realistic experimental consequences. A possible topological origin of the rho and ω universality relations emerges as a by-product of our study

  6. Neutron scattering cross sections of uranium-238

    International Nuclear Information System (INIS)

    Beghian, L.E.; Kegel, G.H.R.; Marcella, T.V.; Barnes, B.K.; Couchell, G.P.; Egan, J.J.; Mittler, A.; Pullen, D.J.; Schier, W.A.

    1979-01-01

    The University of Lowell high-resolution time-of-flight spectrometer was used to measure angular distributions and 90-deg excitation functions for neutrons scattered from 238 U in the energy range from 0.9 to 3.1 MeV. This study was limited to the elastic and the first two inelastic groups, corresponding to states of 238 U at 45 keV (2 + ) and 148 keV (4 + ). Angular distributions were measured at primary neutron energies of 1.1, 1.9, 2.5, and 3.1 MeV for the same three neutron groups. Whereas the elastic data are in fair agreement with the evaluation in the ENDF/B-IV file, there is substantial disagreement between the inelastic measurements and the evaluated cross sections. 12 figures

  7. Fission cross-section normalization problems

    International Nuclear Information System (INIS)

    Wagemans, C.; Ghent Rijksuniversiteit; Deruytter, A.J.

    1983-01-01

    The present measurements yield σsub(f)-data in the neutron energy from 20 MeV to 30 keV directly normalized in the thermal region. In the keV-region these data are consistent with the absolute σsub(f)-measurements of Szabo and Marquette. For the secondary normalization integral I 2 values have been obtained in agreement with those of Gwin et al. and Czirr et al. which were also directly normalized in the thermal region. For the I 1 integral, however, puzzling low values have been obtained. This was also the case for σsub(f)-bar in neutron energy intervals containing strong resonances. Three additional measurements are planned to further investigate these observations: (i) maintaining the actual approx.2π-geometry but using a 10 B-foil for the neutron flux detection (ii) using a low detection geometry with a 10 B- as well as a 6 Li-flux monitor. Only after these measurements definite conclusions on the I 1 and I 2 integrals can be formulated and final σsub(f)-bar-values can be released. The present study also gives some evidence for a correlation between the integral I 2 and the neutron flux monitor used. The influence of a normalization via I 1 or I 2 on the final cross-section has been shown. The magnitude of possible normalization errors is illustrated. Finally, since 235 U is expected to be an ''easy'' nucleus (low α-activity high σsub(f)-values), there are some indications that the important discrepancies still present in 235 U(n,f) cross-section measurements might partially be due to errors in the neutron flux determination

  8. Total and ionization cross sections of electron scattering by fluorocarbons

    International Nuclear Information System (INIS)

    Antony, B K; Joshipura, K N; Mason, N J

    2005-01-01

    Electron impact total cross sections (50-2000 eV) and total ionization cross sections (threshold to 2000 eV) are calculated for typical plasma etching molecules CF 4 , C 2 F 4 , C 2 F 6 , C 3 F 8 and CF 3 I and the CF x (x 1-3) radicals. The total elastic and inelastic cross sections are determined in the spherical complex potential formalism. The sum of the two gives the total cross section and the total inelastic cross section is used to calculate the total ionization cross sections. The present total and ionization cross sections are found to be consistent with other theories and experimental measurements, where they exist. Our total cross section results for CF x (x = 1-3) radicals presented here are first estimates on these species

  9. Mid-IR Absorption Cross-Section Measurements of Hydrocarbons

    KAUST Repository

    Alrefae, Majed Abdullah

    2013-01-01

    -known at combustion-relevant conditions. Absorption cross-section is an important spectroscopic quantity and has direct relation to the species concentration. In this work, the absorption cross-sections of basic hydrocarbons are measured using Fourier Transform

  10. Correction of sampling bias in a cross-sectional study of post-surgical complications.

    Science.gov (United States)

    Fluss, Ronen; Mandel, Micha; Freedman, Laurence S; Weiss, Inbal Salz; Zohar, Anat Ekka; Haklai, Ziona; Gordon, Ethel-Sherry; Simchen, Elisheva

    2013-06-30

    Cross-sectional designs are often used to monitor the proportion of infections and other post-surgical complications acquired in hospitals. However, conventional methods for estimating incidence proportions when applied to cross-sectional data may provide estimators that are highly biased, as cross-sectional designs tend to include a high proportion of patients with prolonged hospitalization. One common solution is to use sampling weights in the analysis, which adjust for the sampling bias inherent in a cross-sectional design. The current paper describes in detail a method to build weights for a national survey of post-surgical complications conducted in Israel. We use the weights to estimate the probability of surgical site infections following colon resection, and validate the results of the weighted analysis by comparing them with those obtained from a parallel study with a historically prospective design. Copyright © 2012 John Wiley & Sons, Ltd.

  11. High order effects in cross section sensitivity analysis

    International Nuclear Information System (INIS)

    Greenspan, E.; Karni, Y.; Gilai, D.

    1978-01-01

    Two types of high order effects associated with perturbations in the flux shape are considered: Spectral Fine Structure Effects (SFSE) and non-linearity between changes in performance parameters and data uncertainties. SFSE are investigated in Part I using a simple single resonance model. Results obtained for each of the resolved and for representative unresolved resonances of 238 U in a ZPR-6/7 like environment indicate that SFSE can have a significant contribution to the sensitivity of group constants to resonance parameters. Methods to account for SFSE both for the propagation of uncertainties and for the adjustment of nuclear data are discussed. A Second Order Sensitivity Theory (SOST) is presented, and its accuracy relative to that of the first order sensitivity theory and of the direct substitution method is investigated in Part II. The investigation is done for the non-linear problem of the effect of changes in the 297 keV sodium minimum cross section on the transport of neutrons in a deep-penetration problem. It is found that the SOST provides a satisfactory accuracy for cross section uncertainty analysis. For the same degree of accuracy, the SOST can be significantly more efficient than the direct substitution method

  12. Neutron-induced cross-sections via the surrogate method

    International Nuclear Information System (INIS)

    Boutoux, G.

    2011-11-01

    The surrogate reaction method is an indirect way of determining neutron-induced cross sections through transfer or inelastic scattering reactions. This method presents the advantage that in some cases the target material is stable or less radioactive than the material required for a neutron-induced measurement. The method is based on the hypothesis that the excited nucleus is a compound nucleus whose decay depends essentially on its excitation energy and on the spin and parity state of the populated compound state. Nevertheless, the spin and parity population differences between the compound-nuclei produced in the neutron and transfer-induced reactions may be different. This work reviews the surrogate method and its validity. Neutron-induced fission cross sections obtained with the surrogate method are in general good agreement. However, it is not yet clear to what extent the surrogate method can be applied to infer radiative capture cross sections. We performed an experiment to determine the gamma decay probabilities for 176 Lu and 173 Yb by using the surrogate reactions 174 Yb( 3 He,pγ) 176 Lu * and 174 Yb( 3 He,αγ) 173 Yb * , respectively, and compare them with the well-known corresponding probabilities obtained in the 175 Lu(n,γ) and 172 Yb(n,γ) reactions. This experiment provides answers to understand why, in the case of gamma-decay, the surrogate method gives significant deviations compared to the corresponding neutron-induced reaction. In this work, we have also assessed whether the surrogate method can be applied to extract capture probabilities in the actinide region. Previous experiments on fission have also been reinterpreted. Thus, this work provides new insights into the surrogate method. This work is organised in the following way: in chapter 1, the theoretical aspects related to the surrogate method will be introduced. The validity of the surrogate method will be investigated by means of statistical model calculations. In chapter 2, a review on

  13. Absolute cross sections for the multielectron processes in 15 keV I10++rare gas collisions

    International Nuclear Information System (INIS)

    Nakamura, N.; Currell, F.J.; Danjo, A.; Kimura, M.; Matsumoto, A.; Ohtani, S.; Sakaue, H.A.; Sakurai, M.; Tawara, H.; Watanabe, H.; Yamada, I.; Yoshino, M.

    1995-01-01

    We have experimentally determined the absolute cross sections for total charge transfer (σ q ), j electron transfer (σ j q ), i electron capture (σ q,q-i ) and each reaction process (σ j q,q-i ) in 15 keV I 10+ -Ne, Ar, Kr and Xe collisions. The branching ratios were determined by the coincidence measurements between charge changing projectile and recoil ions. The electron capture cross sections were measured by the initial growth rate method. The experimental results for total and j electron transfer cross sections were compared with the predictions of the extended classical over-barrier model (ECBM). (orig.)

  14. CFRMF spectrum update and application to dosimeter cross-section data testing

    International Nuclear Information System (INIS)

    Anderl, R.A.; Harker, Y.D.; Millsap, D.A.; Rogers, J.W.; Ryskamp, J.M.

    1982-01-01

    The Coupled Fast Reactivity Measurements Facility (CFRMF) at the Idaho National Engineering Laboratory (INEL) is a Cross Section Evaluation Working Group (CSEWG) benchmark for data testing of dosimetry, fission-product and actinide cross sections important to fast-reactor technology. In this paper we present the results of our work in updating the CFRMF spectrum characterization and in applying CFRMF integral data to testing ENDF/B-V dosimeter cross sections. Updated characterization of the central neutron spectrum includes the results of neutronics calculations with ENDF/B-V nuclear data, the generation of a fine-group spectrum representation for integral data-testing applications, and a sensitivity and uncertainty analysis which provides a flux-spectrum covariance matrix related to uncertainties and correlations in the nuclear data used in a neutronics calculation. Our application of CFRMF integral data to cross section testing has included both conventional integral testing analyses and least-squares-adjustment analyses with the FERRET code. The conventional integral data-testing analysis, based on C/E ratios, indicates discrepancies outside the estimated integral test uncertainty for the 6 Li(n,He), 10 B(n,He), 47 Ti(n,p), 58 Fe(n,γ), 197 Au(n,γ) and 232 Th(n,γ) cross sections. The integral test uncertainty included contributions from the measured integral data and from the spectrum and cross sections used to obtain the calculated integral data. Within the uncertainty and correlation specifications for the input spectrum and dosimeter cross sections, the least-squares-adjustment analysis indicated a high degree of consistency between the measured integral data and the ENDF/B-V dosimeter cross sections for all reactions except 10 B

  15. Photoionization cross section of atomic and molecular oxygen

    International Nuclear Information System (INIS)

    Pareek, P.N.

    1983-01-01

    Photoionization cross sections of atomic oxygen and dissociative photoionization cross sections of molecular oxygen were measured from their respective thresholds to 120 angstrom by use of a photoionization mass spectrometer in conjunction with a spark light source. The photoionization cross sections O 2 + parent ion and O + fragment ion from neutral O 2 were obtained by a technique that eliminated the serious problem of identifying the true abundances of O + ions. These ions are generally formed with considerable kinetic energy and, because most mass spectrometers discriminate against energetic ions, true O + abundances are difficult to obtain. In the present work the relative cross sections for producing O + ions are obtained and normalized against the total cross sections in a spectral region where dissociative ionization is not possible. The fragmentation cross sections for O + were then obtained by subtraction of O 2 + cross sections from the known total photoionization cross sections. The results are compared with the previously published measurements. The absolute photoionization cross section of atomic oxygen sigma 8 /sub +/ was measured at 304 A. The actual number density of oxygen atoms within the ionization region was obtained by measuring the fraction of 0 2 molecules dissociated. This sigma/sub +/ at 304 angstrom was used to convert the relative photoinization cross sections, measured as a function of wavelength using a calibrated photodiode, to absolute cross sections. The results are compared with previous measurements and calculated cross sections. angstrom Rydberg series converging to the OII 4 P state was observed

  16. Multilevel parametrization of fissile nuclei resonance cross sections

    International Nuclear Information System (INIS)

    Lukyanov, A.A.; Kolesov, V.V.; Janeva, N.

    1987-01-01

    Because the resonance interference has an important influence on the resonance structure of neutron cross sections energy dependence at lowest energies, multilevel scheme of the cross section parametrization which take into account the resonance interference is used for the description with the same provisions in the regions of the interferential maximum and minimum of the resonance cross sections of the fissile nuclei

  17. Comparison of integral cross section values of several cross section libraries in the SAND-II format

    International Nuclear Information System (INIS)

    Zijp, W.L.; Nolthenius, H.J.

    1978-01-01

    A comparison of some integral cross section values for several cross section libraries in the SAND-II format is presented. The integral cross section values are calculated with aid of the spectrum functions for a Watt fission spectrum, a 1/E spectrum and a Maxwellian spectrum. The libraries which are considered here are CCC-112B, ENDF/B-IV, DETAN74, LAPENAS and CESNEF. These 5 cross section libraries used have all the SAND-II format. (author)

  18. Estimation of Radar Cross Section of a Target under Track

    Directory of Open Access Journals (Sweden)

    Hong Sun-Mog

    2010-01-01

    Full Text Available In allocating radar beam for tracking a target, it is attempted to maintain the signal-to-noise ratio (SNR of signal returning from the illuminated target close to an optimum value for efficient track updates. An estimate of the average radar cross section (RCS of the target is required in order to adjust transmitted power based on the estimate such that a desired SNR can be realized. In this paper, a maximum-likelihood (ML approach is presented for estimating the average RCS, and a numerical solution to the approach is proposed based on a generalized expectation maximization (GEM algorithm. Estimation accuracy of the approach is compared to that of a previously reported procedure.

  19. Validation of new cross section data for the Loviisa reactors

    International Nuclear Information System (INIS)

    Kuusisto, J.

    1995-01-01

    The cross section data used with HEXBU-3D/MOD 5 core simulator code in the reload design calculations of the Loviisa reactors is revised. The new data was calculated with CASMO-HEX code using library based mainly on ENDF/B-IV. The new data is tested against measurements representing both current type low leakage reduced cores and original type full size cores with out-in-in loading patterns. Reactivity coefficients, boron concentration as a function of cycle burnup and assemblywise power distributions are compared to measurements. Slight adjustments are made so that good results are obtained for current type low leakage cores. When the data is applied to initial cores with out-in-in loading pattern some deviations are observed. (orig.) (4 refs., 18 figs.)

  20. R-matrix analyses of the 235U and 239Pu neutron cross sections

    International Nuclear Information System (INIS)

    Derrien, H.; de Saussure, G.; Larson, N.M.; Leal, L.C.; Perez, R.B.

    1988-01-01

    The resonance parameter analysis code SAMMY was used to perform consistent resonance analyses of several 235 U and 239 Pu fission and capture cross section and transmission measurements up to 110 eV for 235 U and up to 1 keV for 239 Pu. The method of analysis, the measurement selection and the results are briefly outlined in this paper

  1. Evaluation of neutron cross-sections for 242Cm to obtain a complete file

    International Nuclear Information System (INIS)

    Bakhanovich, L.A.; Klepetskij, A.B.; Maslov, V.M.; Porodzinskij, Yu.V.; Sukhovitskij, E.Sh.

    1994-01-01

    Experimental fission, capture, inelastic scattering, (n2n), (n3n) and other cross-sections are scarce or unavailable. As a consequence, theoretical models and parameters systematics have been used extensively in the calculation of these data. Data obtained in this work are compared with previous evaluations. Severe discrepancies were found. (author). 10 refs, 2 figs, 2 tabs

  2. Parameterized representation of macroscopic cross section in the PWR fuel element considering burn-up cycles

    International Nuclear Information System (INIS)

    Belo, Thiago F.; Fiel, Joao Claudio B.

    2015-01-01

    Nuclear reactor core analysis involves neutronic modeling and the calculations require problem dependent nuclear data generated with few neutron energy groups, as for instance the neutron cross sections. The methods used to obtain these problem-dependent cross sections, in the reactor calculations, generally uses nuclear computer codes that require a large processing time and computational memory, making the process computationally very expensive. Presently, analysis of the macroscopic cross section, as a function of nuclear parameters, has shown a very distinct behavior that cannot be represented by simply using linear interpolation. Indeed, a polynomial representation is more adequate for the data parameterization. To provide the cross sections of rapidly and without the dependence of complex systems calculations, this work developed a set of parameterized cross sections, based on the Tchebychev polynomials, by fitting the cross sections as a function of nuclear parameters, which include fuel temperature, moderator temperature and density, soluble boron concentration, uranium enrichment, and the burn-up. In this study is evaluated the problem-dependent about fission, scattering, total, nu-fission, capture, transport and absorption cross sections for a typical PWR fuel element reactor, considering burn-up cycle. The analysis was carried out with the SCALE 6.1 code package. The results of comparison with direct calculations with the SCALE code system and also the test using project parameters, such as the temperature coefficient of reactivity and fast fission factor, show excellent agreements. The differences between the cross-section parameterization methodology and the direct calculations based on the SCALE code system are less than 0.03 percent. (author)

  3. Parameterized representation of macroscopic cross section in the PWR fuel element considering burn-up cycles

    Energy Technology Data Exchange (ETDEWEB)

    Belo, Thiago F.; Fiel, Joao Claudio B., E-mail: thiagofbelo@hotmail.com [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    Nuclear reactor core analysis involves neutronic modeling and the calculations require problem dependent nuclear data generated with few neutron energy groups, as for instance the neutron cross sections. The methods used to obtain these problem-dependent cross sections, in the reactor calculations, generally uses nuclear computer codes that require a large processing time and computational memory, making the process computationally very expensive. Presently, analysis of the macroscopic cross section, as a function of nuclear parameters, has shown a very distinct behavior that cannot be represented by simply using linear interpolation. Indeed, a polynomial representation is more adequate for the data parameterization. To provide the cross sections of rapidly and without the dependence of complex systems calculations, this work developed a set of parameterized cross sections, based on the Tchebychev polynomials, by fitting the cross sections as a function of nuclear parameters, which include fuel temperature, moderator temperature and density, soluble boron concentration, uranium enrichment, and the burn-up. In this study is evaluated the problem-dependent about fission, scattering, total, nu-fission, capture, transport and absorption cross sections for a typical PWR fuel element reactor, considering burn-up cycle. The analysis was carried out with the SCALE 6.1 code package. The results of comparison with direct calculations with the SCALE code system and also the test using project parameters, such as the temperature coefficient of reactivity and fast fission factor, show excellent agreements. The differences between the cross-section parameterization methodology and the direct calculations based on the SCALE code system are less than 0.03 percent. (author)

  4. Graphs of the cross sections in the recommended Monte Carlo cross-section library at the Los Alamos Scientific Laboratory

    International Nuclear Information System (INIS)

    Soran, P.D.; Seamon, R.E.

    1980-05-01

    Graphs of all neutron cross sections and photon production cross sections on the Recommended Monte Carlo Cross Section (RMCCS) library have been plotted along with local neutron heating numbers. Values for anti ν, the average number of neutrons per fission, are also given

  5. Graphs of the cross sections in the Alternate Monte Carlo Cross Section library at the Los Alamos Scientific Laboratory

    International Nuclear Information System (INIS)

    Seamon, R.E.; Soran, P.D.

    1980-06-01

    Graphs of all neutron cross sections and photon production cross sections on the Alternate Monte Carlo Cross Section (AMCCS) library have been plotted along with local neutron heating numbers. The values of ν-bar, the average number of neutrons per fission, are also plotted for appropriate isotopes

  6. Accurate measurements of neutron activation cross sections

    International Nuclear Information System (INIS)

    Semkova, V.

    1999-01-01

    The applications of some recent achievements of neutron activation method on high intensity neutron sources are considered from the view point of associated errors of cross sections data for neutron induced reaction. The important corrections in -y-spectrometry insuring precise determination of the induced radioactivity, methods for accurate determination of the energy and flux density of neutrons, produced by different sources, and investigations of deuterium beam composition are considered as factors determining the precision of the experimental data. The influence of the ion beam composition on the mean energy of neutrons has been investigated by measurement of the energy of neutrons induced by different magnetically analysed deuterium ion groups. Zr/Nb method for experimental determination of the neutron energy in the 13-15 MeV energy range allows to measure energy of neutrons from D-T reaction with uncertainty of 50 keV. Flux density spectra from D(d,n) E d = 9.53 MeV and Be(d,n) E d = 9.72 MeV are measured by PHRS and foil activation method. Future applications of the activation method on NG-12 are discussed. (author)

  7. [Fast neutron cross section measurements]: Progress report

    International Nuclear Information System (INIS)

    1988-01-01

    As projected in our previous proposal, the past year on the cross section project at the University of Michigan has been one primarily of construction and assembly of our 14 MeV pulsed Neutron Facility. All the components of the system have now been either purchased or fabricated in our shop facilities and have been assembled in their final configuration. We are now in the process of testing the rf components that have been designed to deliver voltage to both the pulser and buncher stages. We expect that the system will be operational by the end of the current contract year. We have also accomplished the design and construction of several other major pieces of equipment that are needed to begin fast neutron time-of-flight measurements. These include the primary proton recoil detector, and a californium fission chamber needed in the efficiency calibration of the primary detector. We have also added considerable concrete shielding designed to lower the neutron background in the experimental area. 10 figs., 5 tabs

  8. Josephson cross-sectional model experiment

    International Nuclear Information System (INIS)

    Ketchen, M.B.; Herrell, D.J.; Anderson, C.J.

    1985-01-01

    This paper describes the electrical design and evaluation of the Josephson cross-sectional model (CSM) experiment. The experiment served as a test vehicle to verify the operation at liquid-helium temperatures of Josephson circuits integrated in a package environment suitable for high-performance digital applications. The CSM consisted of four circuit chips assembled on two cards in a three-dimensional card-on-board package. The chips (package) were fabricated in a 2.5-μm (5-μm) minimum linewidth Pb-alloy technology. A hierarchy of solder and pluggable connectors was used to attach the parts together and to provide electrical interconnections between parts. A data path which simulated a jump control sequence and a cache access in each machine cycle was successfully operated with cycle times down to 3.7 ns. The CSM incorporated the key components of the logic, power, and package of a prototype Josephson signal processor and demonstrated the feasibility of making such a processor with a sub-4-ns cycle time

  9. New resonance cross section calculational algorithms

    International Nuclear Information System (INIS)

    Mathews, D.R.

    1978-01-01

    Improved resonance cross section calculational algorithms were developed and tested for inclusion in a fast reactor version of the MICROX code. The resonance energy portion of the MICROX code solves the neutron slowing-down equations for a two-region lattice cell on a very detailed energy grid (about 14,500 energies). In the MICROX algorithms, the exact P 0 elastic scattering kernels are replaced by synthetic (approximate) elastic scattering kernels which permit the use of an efficient and numerically stable recursion relation solution of the slowing-down equation. In the work described here, the MICROX algorithms were modified as follows: an additional delta function term was included in the P 0 synthetic scattering kernel. The additional delta function term allows one more moments of the exact elastic scattering kernel to be preserved without much extra computational effort. With the improved synthetic scattering kernel, the flux returns more closely to the exact flux below a resonance than with the original MICROX kernel. The slowing-down calculation was extended to a true B 1 hyperfine energy grid calculatn in each region by using P 1 synthetic scattering kernels and tranport-corrected P 0 collision probabilities to couple the two regions. 1 figure, 6 tables

  10. Cross Section Measurements of the Reaction 23Na(p, γ)24Mg

    Science.gov (United States)

    Boeltzig, Axel; Deboer, Richard James; Macon, Kevin; Wiescher, Michael; Best, Andreas; Imbriani, Gianluca; Gyürky, György; Strieder, Frank

    2017-09-01

    The reaction 23Na(p, γ)24Mg can provide a link from the NeNa to the MgAl cycle in stellar burning and is therefore of interest in nuclear astrophysics. To determine the reaction rates at stellar temperatures, new cross section measurements at low proton energies have been performed recently, and further experiments are underway. The current cross section data implies that the reaction rate up to temperatures of 1 GK is determined by a few narrow resonances and direct capture. Complementary to these experimental efforts at low proton energies, cross section measurements at higher energies can help to constrain the direct capture and broad resonance contributions to the cross section and reduce the uncertainty of the extrapolation towards stellar energies. In this paper we report an experiment to measure the 23Na(p, γ)24Mg cross section with a solid target setup at the St. ANA 5U accelerator at the University of Notre Dame. The experiment and the current status of data analysis will be described. This work benefited from support by the National Science Foundation under Grant No. PHY-1430152 (JINA-CEE), the Nuclear Science Laboratory (NSL), the Istituto Nazionale di Fisica Nucleare (INFN), and the Gran Sasso Science Institute (GSSI).

  11. Neutron cross section libraries for analysis of fusion neutronics experiments

    International Nuclear Information System (INIS)

    Kosako, Kazuaki; Oyama, Yukio; Maekawa, Hiroshi; Nakamura, Tomoo

    1988-03-01

    We have prepared two computer code systems producing neutron cross section libraries to analyse fusion neutronics experiments. First system produces the neutron cross section library in ANISN format, i.e., the multi-group constants in group independent format. This library can be obtained by using the multi-group constant processing code system MACS-N and the ANISN format cross section compiling code CROKAS. Second system is for the continuous energy cross section library for the MCNP code. This library can be obtained by the nuclear data processing system NJOY which generates pointwise energy cross sections and the cross section compiling code MACROS for the MCNP library. In this report, we describe the production procedures for both types of the cross section libraries, and show six libraries with different conditions in ANISN format and a library for the MCNP code. (author)

  12. Preparation of next generation set of group cross sections. 3

    International Nuclear Information System (INIS)

    Kaneko, Kunio

    2002-03-01

    This fiscal year, based on the examination result about the evaluation energy range of heavy element unresolved resonance cross sections, the upper energy limit of the energy range, where ultra-fine group cross sections are produced, was raised to 50 keV, and an improvement of the group cross section processing system was promoted. At the same time, reflecting the result of studies carried out till now, a function producing delayed neutron data was added to the general-purpose group cross section processing system , thus the preparation of general purpose group cross section processing system has been completed. On the other hand, the energy structure, data constitution and data contents of next generation group cross section set were determined, and the specification of a 151 groups next generation group cross section set was defined. Based on the above specification, a concrete library format of the next generation cross section set has been determined. After having carried out the above-described work, using the general-purpose group cross section processing system , which was complete in this study, with use of the JENDL-3. 2 evaluated nuclear data, the 151 groups next generation group cross section of 92 nuclides and the ultra fine group resonance cross section library for 29 nuclides have been prepared. Utilizing the 151 groups next generation group cross section set and the ultra-fine group resonance cross-section library, a bench mark test calculation of fast reactors has been performed by using an advanced lattice calculation code. It was confirmed, by comparing the calculation result with a calculation result of continuous energy Monte Carlo code, that the 151 groups next generation cross section set has sufficient accuracy. (author)

  13. Nuclear Data Processing for Generation of Stainless Steel Cross-Sections Data

    International Nuclear Information System (INIS)

    Suwoto; Zuhair

    2007-01-01

    Stainless steel has been used as important material in nuclear reactor and also in non nuclear industries. Nuclear data processing for generation of composite mixture cross-sections from several nuclides have been made. Provided evaluated nuclear data file (ENDF) such as ENDF/B- VI.8, JEFF-3.1 and JENDL-3.3 files were employed. Raw nuclear data cross-sections on file ENDF should be prepared and processed before it used in calculation. Sequence of nuclear data processing for generation of mixture cross-sections data from several nuclides is started from LINEAR, RECENT, SIGMA1 and MIXER codes taken from PREPR02000 utility code. Nuclear data processing is started from linearization of nuclear cross-sections data by using LINEAR code and counting background contribution of resonance parameter (MF2) with RECENT code (0 K) at energy ranges from 10 -5 to 10 7 eV. Afterward, the neutron cross-sections data should be processed and broadened to desire temperature (300 K) by using SIGMA1 code. Consistency of each cross-sections which used in nuclear data processing is checked and verified using FIXUP code. The next step is to define the composite mixture density (gr/cm 3 ) of stainless steel SUS-310 and weight fraction of each nuclide composition prior used it in MIXER code. All of the stainless steel SUS-310 cross sections are condensed to 650 energy groups structure (TART-energy structure) by using GROUPIE code to evaluate, analysis and review it more easily. The total, elastic scattering, non-elastic scattering and capture cross- sections of stainless steel SUS-310 have been made of ENDF/B-VI.8, JEFF-3.1 and JENDL-3.3 files. The stainless steel cross-sections made of ENDF/B- VI.8 file was taken as reference during validation process. The validation result of total cross-sections for stainless steel SUS-310 is clearly observed that the differences of total cross-sections error in nuclear data processing is relatively low than 0.01%. (author)

  14. Comparison of integral cross section values of several cross section libraries in the SAND-II format

    International Nuclear Information System (INIS)

    Zijp, W.L.; Nolthenius, H.J.

    1976-09-01

    A comparison of some integral cross-section values for several cross-section libraries in the SAND-II format is presented. The integral cross-section values are calculated with the aid of the spectrum functions for a Watt fission spectrum, a 1/E spectrum and a Maxwellian spectrum. The libraries which are considered here are CCC-112B, ENDF/B-IV, DETAN74, LAPENAS and CESNEF. These 5 cross-section libraries used have all the SAND-II format. Discrepancies between cross-sections in the different libraries are indicated but not discussed

  15. Assessment of Fission Product Cross-Section Data for Burnup Credit Applications

    International Nuclear Information System (INIS)

    Leal, Luiz C; Derrien, Herve; Dunn, Michael E; Mueller, Don

    2007-01-01

    international nuclear data community as of March 2005. The accuracy of the cross-section data was investigated by comparing existing cross-section evaluations against available measured cross-section data. When possible, benchmark calculations were also used to assess the performance of the latest FP cross-section data. Since March 2005, the U.S. and European data projects have released newer versions of their respective data files. Although there have been updates to the international data files and to some degree FP data, much of the updates have included nuclear cross-section modeling improvements at energies above the resonance region. The one exception is improved ENDF/B-VII cross-section uncertainty data or covariance data for gadolinium isotopes. In particular, ENDF/B-VII includes improved 155Gd resonance parameter covariance data, but they are based on previously measured resonance data. Although the new covariance data are available for 155Gd, the conclusions of the FP cross-section data assessment of this report still hold in lieu of the newer international cross-section data files. Based on the FP data assessment, there is judged to be a need for new total and capture cross-section measurements and corresponding cross-section evaluations, in a prioritized manner, for the nine FPs to provide the improved information and technical rigor needed for criticality safety analyses

  16. Neutron cross section covariances in the resonance region: 52Cr, 56Fe, 58Ni

    Energy Technology Data Exchange (ETDEWEB)

    Oblozinsky, P.; Cho, Y.-S.; Mattoon, C.M.; Mughabghab, S.F.

    2010-08-03

    We evaluated covariances for neutron capture and elastic scattering cross sections on major structural materials, {sup 52}Cr, {sup 56}Fe and {sup 58}Ni, in the resonance region which extends beyond 800 keV for each of them. Use was made of the recently developed covariance formalism based on kernel approximation along with data in the Atlas of Neutron Resonances. The data of most interest for AFCI applications, elastic scattering cross section uncertainties at energies above about few hundred keV, are on the level of about 12% for {sup 52}Cr, 7-8% for {sup 56}Fe and 5-6% for {sup 58}Ni.

  17. A probability-conserving cross-section biasing mechanism for variance reduction in Monte Carlo particle transport calculations

    OpenAIRE

    Mendenhall, Marcus H.; Weller, Robert A.

    2011-01-01

    In Monte Carlo particle transport codes, it is often important to adjust reaction cross sections to reduce the variance of calculations of relatively rare events, in a technique known as non-analogous Monte Carlo. We present the theory and sample code for a Geant4 process which allows the cross section of a G4VDiscreteProcess to be scaled, while adjusting track weights so as to mitigate the effects of altered primary beam depletion induced by the cross section change. This makes it possible t...

  18. The H(n,n) cross section in the 20 MeV to 350 MeV range

    International Nuclear Information System (INIS)

    1997-01-01

    The differential H(n,n) cross section has been used as a standard relative to which other neutron emission cross sections, e.g., elastic or inelastic scattering, have been measured in several Mev region and these measured values are compared with the VL40 solution of R. Arndt, and R.L. Workman, Nuclear Data Standards for Nuclear Measurements, H. Conde (ed.). NEANDC-311, INDC (SEC)-101, 1992, p. 17. For hydrogen, the differential elastic scattering cross section can be directly related to the total cross section, since no other channels of importance are open below the pion production threshold at about 280 MeV (the capture and Bremsstrahlung cross section are very small). 16 refs, 3 figs

  19. Electron and positron atomic elastic scattering cross sections

    International Nuclear Information System (INIS)

    Stepanek, Jiri

    2003-01-01

    A method was developed to calculate the total and differential elastic-scattering cross sections for incident electrons and positrons in the energy range from 0.01 eV to 1 MeV for atoms of Z=1-100. For electrons, hydrogen, helium, nitrogen, oxygen, krypton, and xenon, and for positrons, helium, neon, and argon atoms were considered for comparison with experimental data. First, the variationally optimized atomic static potentials were calculated for each atom by solving the Dirac equations for bound electron states. Second, the Dirac equations for a free electron or positron are solved for an atom using the previously calculated static potential accomplished (in the case of electrons) by 'adjusted' Hara's exchange potential for a free-state particle. Additional to the exchange effects, the charge cloud polarization effects are considered applying the correlation-polarization potential of O'Connell and Lane (with correction of Padial and Norcross) for incident electrons, and of Jain for incident positrons. The total, cutoff and differential elastic-scattering cross sections are calculated for incident electrons and positrons with the help of the relativistic partial wave analysis. The solid state effects for scattering in solids are described by means of a muffin-tin model, i.e. the potentials of neighboring atoms are superpositioned in such a way that the resulting potential and its derivative are zero in the middle distance between the atoms. The potential of isolated atom is calculated up to the radius at which the long-range polarization potential becomes a value of -10 -8

  20. Average cross sections for the 252Cf neutron spectrum

    International Nuclear Information System (INIS)

    Dezso, Z.; Csikai, J.

    1977-01-01

    A number of average cross sections have been measured for 252 Cf neutrons in (n, γ), (n,p), (n,2n), (n,α) reactions by the activation method and for fission by fission chamber. Cross sections have been determined for 19 elements and 45 reactions. The (n,γ) cross section values lie in the interval from 0.3 to 200 mb. The data as a function of target neutron number increases up to about N=60 with minimum near to dosed shells. The values lie between 0.3 mb and 113 mb. These cross sections decrease significantly with increasing the threshold energy. The values are below 20 mb. The data do not exceed 10 mb. Average (n,p) cross sections as a function of the threshold energy and average fission cross sections as a function of Zsup(4/3)/A are shown. The results obtained are summarized in tables