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Sample records for reaction cross sections

  1. Reaction cross sections of unstable nuclei

    SciTech Connect

    Ozawa, Akira

    2006-11-02

    Experimental studies on reaction cross sections are reviewed. The recent developments of radioactive nuclear beams have enabled us to measure reaction cross-sections for unstable nuclei. Using Glauber-model analysis, effective nuclear matter density distributions of unstable nuclei can be studied. Recent measurements in RIBLL at IMP and RIPS at RIKEN are introduced. The effective matter density distributions for 14-18C are also mentioned.

  2. Cross sections of neutron-induced reactions

    SciTech Connect

    Mukhopadhyay, Tapan; Lahiri, Joydev; Basu, D. N.

    2010-10-15

    We study the properties of the neutron-nucleus total and reaction cross sections for several nuclei. We have applied an analytical model, the nuclear Ramsauer model, justified it from the nuclear reaction theory approach, and extracted the values of 12 parameters used in the model. The given parametrization has an advantage as phenomenological optical model potentials are limited up to 150-200 MeV. The present model provides good estimates of the total cross sections for several nuclei particularly at high energies.

  3. Reduction Methods for Total Reaction Cross Sections

    NASA Astrophysics Data System (ADS)

    Gomes, P. R. S.; Mendes Junior, D. R.; Canto, L. F.; Lubian, J.; de Faria, P. N.

    2016-03-01

    The most frequently used methods to reduce fusion and total reaction excitation functions were investigated in a very recent paper Canto et al. (Phys Rev C 92:014626, 2015). These methods are widely used to eliminate the influence of masses and charges in comparisons of cross sections for weakly bound and tightly bound systems. This study reached two main conclusions. The first is that the fusion function method is the most successful procedure to reduce fusion cross sections. Applying this method to theoretical cross sections of single channel calculations, one obtains a system independent curve (the fusion function), that can be used as a benchmark to fusion data. The second conclusion was that none of the reduction methods available in the literature is able to provide a universal curve for total reaction cross sections. The reduced single channel cross sections keep a strong dependence of the atomic and mass numbers of the collision partners, except for systems in the same mass range. In the present work we pursue this problem further, applying the reduction methods to systems within a limited mass range. We show that, under these circumstances, the reduction of reaction data may be very useful.

  4. Derivation of reaction cross sections from experimental elastic backscattering probabilities

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    The relationship between the backward elastic scattering probabilities and the reaction cross sections is derived. This is a very simple and useful method to extract reaction cross sections for heavy-ion systems. We compare the results of our method with those that use the traditional full elastic scattering angular distributions for several systems at energies near and above the Coulomb barrier. From the calculated reaction and capture cross sections that use the present method, we derive the cross sections of other mechanisms for weak nearly spherical systems.

  5. General Constraints on Cross Sections Deduced from Surrogate Reactions

    SciTech Connect

    Younes, W

    2003-08-14

    Cross sections that cannot be measured in the laboratory, e.g. because the target lifetime is too short, can be inferred indirectly from a different reaction forming the same compound system, but with a more accessible beam/target combination (the ''surrogate-reaction'' technique). The reactions share the same compound system and a common decay mechanism, but they involve different formation processes. Therefore, an implicit constraint is imposed on the inferred cross section deduced from the measured surrogate-reaction data, through the common decay mechanism. In this paper, the mathematical consequences of this implicit constraint are investigated. General formulas are derived from upper and lower bounds on the inferred cross section, estimated from surrogate data in a procedure which does not require any modeling of the common decay process. As an example, the formulas developed here are applied to the case of the {sup 235}U(n,f) cross section, deduced from {sup 234}U(t,pf) surrogate data. The calculated bounds are not very tight in this particular case. However, by introducing a few qualitative assumptions about the physics of the fission process, meaningful bounds on the deduced cross section are obtained. Upper and lower limits for the cross-section ratio of the (n,f) reaction on the {sup 235}U isomer at E{sub x} = 77 eV relative to the (n,f) reaction on the ground state are also calculated. The generalization of this technique to other surrogate reactions is discussed.

  6. A new technique for dosimetry reaction cross-section evaluation

    SciTech Connect

    Badikov, S.A.

    2011-07-01

    Document available in abstract form only, full text of document follows: An objective of this paper is a unification of the procedure for dosimetry reaction cross-section evaluation. A set of requirements for the unified evaluation procedure is presented. A new code (ORTHO) was developed in order to meet these requirements. A statistical model, an algorithm, and the basic formulae employed in the code are described. The code was used for Ti48(n,p) reaction cross-section evaluation. The results of the evaluation are compared to International Reactor Dosimetry File (IRDF)-2002 data. The evaluated cross-sections and their correlations from this work are in good agreement with the IRDF-2002 evaluated data, whereas the uncertainties of the evaluated cross-sections are inconsistent. (authors)

  7. Systematic analysis of reaction cross sections of carbon isotopes

    SciTech Connect

    Horiuchi, W.; Suzuki, Y.; Abu-Ibrahim, B.; Kohama, A.

    2007-04-15

    We systematically analyze total reaction cross sections of carbon isotopes with N= 6-16 on a {sup 12}C target for wide range of incident energy. The intrinsic structure of the carbon isotope is described by a Slater determinant generated from a phenomenological mean-field potential, which reasonably well reproduces the ground-state properties for most of the even N isotopes. We need separate studies not only for odd nuclei but also for {sup 16}C and {sup 22}C to improve their wave functions. The density of the carbon isotope is constructed by eliminating the effect of the center-of-mass motion. For the calculations of the cross sections, we take two schemes, the Glauber approximation and the eikonal model using a global optical potential. Both the reaction models successfully reproduce low and high incident energy data on the cross sections of {sup 12}C, {sup 13}C, and {sup 16}C on {sup 12}C. The calculated reaction cross sections of {sup 15}C are found to be considerably smaller than the empirical values observed at low energy. We find a consistent parametrization of the nucleon-nucleon scattering amplitude, differently from previous ones. Finally, we predict the total reaction cross section of {sup 22}C on {sup 12}C.

  8. Reaction cross sections of carbon isotopes incident on a proton

    SciTech Connect

    Abu-Ibrahim, B.; Horiuchi, W.; Kohama, A.; Suzuki, Y.

    2008-03-15

    We systematically study total reaction cross sections of carbon isotopes with N=6-16 on a proton target for wide range of incident energies. An emphasis is put on the difference from the case of a carbon target. The calculations include the reaction cross sections of {sup 19,20,22}C at 40A MeV, the data of which have recently been measured at RIKEN. The Glauber theory is used to calculate the reaction cross sections. To describe the intrinsic structure of the carbon isotopes, we use a Slater determinant generated from a phenomenological mean-field potential, and construct the density distributions. To go beyond the simple mean-field model, we adopt two types of dynamical models: One is a core+n model for odd-neutron nuclei, and the other is a core+n+n model for {sup 16}C and {sup 22}C. We propose empirical formulas which are useful in predicting unknown cross sections.

  9. Cross sections and reaction rates of relevance to aeronomy

    SciTech Connect

    Fox, J.L. )

    1991-01-01

    Experimental and theoretical data relevant to models and measurements of the chemical and thermal structures and luminosity of the thermospheres of the earth and planets published during the last four years are surveyed. Among chemical processes, attention is given to ion-molecule reactions, dissociative recombination of molecular ions, and reactions between neutral species. Both reactions between ground state species and species in excited states are considered, including energy transfer and quenching. Measured and calculated cross sections for interactions of solar radiation with atmospheric species, such as photoabsorption, photoionization, and photodissociation and related processes are surveyed.

  10. (n,α) reactions cross section research at IPPE

    NASA Astrophysics Data System (ADS)

    Khryachkov, V. A.; Bondarenko, I. P.; Kuzminov, B. D.; Semenova, N. N.; Sergachev, A. I.; Ivanova, T. A.; Giorginis, G.

    2012-02-01

    An experimental set-up based on an ionization chamber with a Frisch grid and wave form digitizer was used for (n,α) cross section measurements. Use of digital signal processing allowed us to select a gaseous cell inside the sensitive area of the ionization chamber and determine the target atoms in it with high accuracy. This kind of approach provided us with a powerful method to suppress background arising from the detector structure and parasitic reactions on the working gas components. This method is especially interesting to study neutron reactions with elements for which solid target preparation is difficult (noble gases for example). In the present experiments we used a set of working gases which contained admixtures of nitrogen, oxygen, neon, argon and boron. Fission of 238U was used as neutron flux monitor. The cross section of the (n,α) reaction for 16O, 14N, 20Ne, 36Ar, 40Ar and the yield ratio α0/α1 of 10B(n,α0) to 10B(n,α1) reactions was measured for neutron energies between 1.5 and 7 MeV. Additionally a measurement of the 50Cr(n,α) cross section using a solid chromium target is also reported.

  11. Alpha Induced Reaction Cross Section Calculations of Tantalum Nucleus

    NASA Astrophysics Data System (ADS)

    Tel, E.; Ugur, F. A.; Gokce, A. A.

    2013-04-01

    The fusion energy is attractive as an energy source because the fusion will not produce CO2 or SO2 and so fusion will not contribute to environmental problems, such as particulate pollution and excessive CO2 in the atmosphere. The fusion reaction does not produce radioactive nuclides and it is not self-sustaining, as is a fission reaction when a critical mass of fissionable material is assembled. Since the fusion reaction is easily and quickly quenched the primary sources of heat to drive such an accident are heat from radioactive decay and heat from chemical reactions. Both the magnitude and time dependence of the generation of heat from radioactive decay can be controlled by proper selection and design of materials. Tantalum is one of the candidate materials for the first wall of fusion reactors and for component parts of irradiation chambers. Accurate experimental cross-section data of alpha induced reactions on Tantalum are also of great importance for thermonuclear reaction rate determinations since the models used in the study of stellar nucleosynthesis are strongly dependent on these rates (Santos et al. in J Phys G 26:301, 2000). In this study, neutron-production cross sections for target nuclei 181Ta have been investigated up to 100 MeV alpha energy. The excitation functions for (α, xn) reactions (x = 1, 2, 3) have been calculated by pre-equilibrium reaction mechanism. And also neutron emission spectra for 181Ta (α, xn) reactions at 26.8 and 45.2 MeV have been calculated. The mean free path multiplier parameters has been investigated. The pre-equilibrium results have been calculated by using the hybrid model, the geometry dependent hybrid (GDH) model. Calculation results have been also compared with the available measurements in literature.

  12. Calculation of the Reaction Cross Section for Several Actinides

    SciTech Connect

    Hambsch, Franz-Josef; Oberstedt, Stephan; Vladuca, Gheorghita; Tudora, Anabella; Filipescu, Dan

    2005-05-24

    New, self-consistent, neutron-induced reaction cross-section calculations for 235,238U, 237Np, and 231,232,233Pa have been performed. The statistical model code STATIS was extended to take into account the multi-modality of the fission process. The three most dominant fission modes, the two asymmetric standard I (S1) and standard II (S2) modes, and the symmetric superlong (SL) mode have been taken into account. De-convoluted fission cross sections for these modes in 235,238U(n,f) and 237Np(n,f) based on experimental branching ratios, were calculated for the first time up to the second chance fission threshold. For 235U(n,f) and 233Pa(n,f), the calculations being made up to 50 MeV and 20 MeV incident neutron energy, respectively, higher fission chances have been considered. This implied the need for additional calculations for the neighbouring isotopes.As a side product also mass yield distributions could be calculated at energies hitherto not accessible by experiment. Experimental validation of the predictions is being envisaged.

  13. Glauber model for {alpha}-nucleus total reaction cross section

    SciTech Connect

    Chauhan, Deeksha; Khan, Z. A.

    2009-11-15

    The Coulomb-modified Glauber model is employed to calculate the total reaction cross section ({sigma}{sub R}) for {alpha} particles from {sup 9}Be, {sup 12}C, {sup 16}O, {sup 28}Si, {sup 40}Ca, {sup 58,60}Ni, {sup 112,116,120,124}Sn, and {sup 208}Pb at 117.2, 163.9, and 192.4 MeV and from the lighter nuclei also at 69.6 MeV. Our main focus in this work is to assess the suitability of semiphenomenological parametrization of the NN amplitude (SPNN), used recently [Deeksha Chauhan and Z. A. Khan, Eur. Phys. J. A 41, 179 (2009)], in the analysis of {sigma}{sub R} at the energies under consideration. Using the realistic form factors for the colliding nuclei, it is found that the SPNN works reasonably well and we have quite a satisfactory account of the {sigma}{sub R} data in all the cases. Moreover, our analysis suggests that the SPNN could be taken as fairly stable to describe simultaneously the elastic angular distribution and the {sigma}{sub R} for a wide range of target nuclei in the relatively low-energy region.

  14. A Multigroup Reaction Cross-Section Collapsing Code and Library of 154-Group Fission-Product Cross Sections.

    Energy Science and Technology Software Center (ESTSC)

    1983-03-23

    Version 01/02 The code reads multigroup cross sections from a compatible data file and collapses user-selected reaction cross sections to any few-group structure using one of a variety of user neutron flux spectrum options given below: Option Flux description 1 Built-in function including Maxwellian, fission, fusion and slowing-down regions and requiring user-specified parameters and energy-region boundaries. 2 Set of log-log flux-energy interpolation points read from input cross-section data file. 3 Set of log-log flux-energy interpolationmore » points read from user-supplied card input. 4 - 6 Histogram flux values read from user-supplied card input in arbitrary group structure in units of flux-per unit-energy, flux-per-unit lethargy, or integral group flux. LAFPX-E may be used to collapse any set of multigroup reaction cross sections furnished in the required format. However, the code was developed for, and is furnished with, a library of 154-group fission-product cross sections processed from ENDF/B-IV with a typical light water reactor (LWR) flux spectrum and temperature. Four-group radiative capture cross sections produced for LWR calculations are tabulated in the code documentation and are incorporated in the EPRI-CINDER data library, RSIC Code Package CCC-309.« less

  15. Deriving capture and reaction cross sections from observed quasi-elastic and elastic backscattering

    NASA Astrophysics Data System (ADS)

    Sargsyan, V. V.; Adamian, G. G.; Antonenko, N. V.; Diaz-Torres, A.; Gomes, P. R. S.; Lenske, H.

    2014-12-01

    Based on reaction theory, we suggest a useful method for extracting total and partial reaction and capture (complete fusion) cross sections from the experimental elastic and quasi-elastic backscattering excitation functions taken at a single angle. We also propose a method to predict the differential reaction cross section from the observed elastic-scattering angular distribution.

  16. Modeled Neutron Induced Nuclear Reaction Cross Sections for Radiochemistry in the region of Iriduim and Gold

    SciTech Connect

    Hoffman, R D; Dietrich, F S; Kelley, K; Escher, J; Bauer, R; Mustafa, M

    2008-02-26

    We have developed a set of modeled nuclear reaction cross sections for use in radiochemical diagnostics. Systematics for the input parameters required by the Hauser-Feshbach statistical model were developed and used to calculate neutron induced nuclear reaction cross sections for targets ranging from osmium (Z = 76) to gold (Z = 79). Of particular interest are the cross sections on Ir and Au including reactions on isomeric targets.

  17. Impact of Reaction Cross Section on the Unified Description of Fusion Excitation Function

    NASA Astrophysics Data System (ADS)

    Basrak, Z.; Eudes, P.; de la Mota, V.; Sébille, F.; Royer, G.

    A systematics of over 300 complete and incomplete fusion cross section data points covering energies beyond the barrier for fusion is presented. Owing to a usual reduction of the fusion cross sections by the total reaction cross sections and an original scaling of energy, a fusion excitation function common to all the data points is established. A universal description of the fusion exci- tation function relying on basic nuclear concepts is proposed and its dependence on the reaction cross section used for the cross section normalization is discussed. The pioneering empirical model proposed by Bass in 1974 to describe the complete fusion cross sections is rather successful for the incomplete fusion too and provides cross section predictions in satisfactory agreement with the observed universality of the fusion excitation function. The sophisticated microscopic transport DYWAN model not only reproduces the data but also predicts that fusion reaction mechanism disappears due to weakened nuclear stopping power around the Fermi energy.

  18. Total reaction cross sections in CEM and MCNP6 at intermediate energies

    SciTech Connect

    Kerby, Leslie M.; Mashnik, Stepan G.

    2015-05-14

    Accurate total reaction cross section models are important to achieving reliable predictions from spallation and transport codes. The latest version of the Cascade Exciton Model (CEM) as incorporated in the code CEM03.03, and the Monte Carlo N-Particle transport code (MCNP6), both developed at Los Alamos National Laboratory (LANL), each use such cross sections. Having accurate total reaction cross section models in the intermediate energy region (50 MeV to 5 GeV) is very important for different applications, including analysis of space environments, use in medical physics, and accelerator design, to name just a few. The current inverse cross sections used in the preequilibrium and evaporation stages of CEM are based on the Dostrovsky et al. model, published in 1959. Better cross section models are now available. Implementing better cross section models in CEM and MCNP6 should yield improved predictions for particle spectra and total production cross sections, among other results.

  19. Nuclear reaction cross sections of exotic nuclei in the Glauber model for relativistic mean field densities

    SciTech Connect

    Patra, S. K.; Panda, R. N.; Arumugam, P.; Gupta, Raj K.

    2009-12-15

    We have calculated the total nuclear reaction cross sections of exotic nuclei in the framework of the Glauber model, using as inputs the standard relativistic mean field (RMF) densities and the densities obtained from the more recently developed effective-field-theory-motivated RMF (the E-RMF). Both light and heavy nuclei are taken as the representative targets, and the light neutron-rich nuclei as projectiles. We found the total nuclear reaction cross section to increase as a function of the mass number, for both the target and projectile nuclei. The differential nuclear elastic scattering cross sections are evaluated for some selected systems at various incident energies. We found a large dependence of the differential elastic scattering cross section on incident energy. Finally, we have applied the same formalism to calculate both the total nuclear reaction cross section and the differential nuclear elastic scattering cross section for the recently discussed superheavy nucleus with atomic number Z=122.

  20. The Status of Cross Section Measurements for Neutron-induced Reactions Needed for Cosmic Ray Studies

    NASA Technical Reports Server (NTRS)

    Sisterson, J. M.

    2003-01-01

    Cosmic ray interactions with lunar rocks and meteorites produce small amounts of radionuclides and stable isotopes. Advances in Accelerator Mass Spectrometry (AMS) allow production rates to be measured routinely in well-documented lunar rocks and meteorites. These measurements are analyzed using theoretical models to learn about the object itself and the history of the cosmic rays that fell on it. Good cross section measurements are essential input to the theoretical calculations. Most primary cosmic ray particles are protons so reliable cross sections for proton-induced reactions are essential. A cross section is deemed accurate if measurements made by different experimenters using different techniques result in consistent values. Most cross sections for proton induced reactions are now well measured. However, good cross section measurements for neutron-induced reactions are still needed. These cross sections are required to fully account for all galactic cosmic ray interactions at depth in an extraterrestrial object. When primary galactic cosmic ray (GCR) particles interact with an object many secondary neutrons are produced, which also initiate spallation reactions. Thus, the total GCR contribution to the overall cosmogenic nuclide archive has to include the contribution from the secondary neutron interactions. Few relevant cross section measurements have been reported for neutron-induced reactions at neutron energies greater than approximately 20 MeV. The status of the cross section measurements using quasi-monoenergetic neutron energies at iThemba LABS, South Africa and white neutron beams at Los Alamos Neutron Science Center (LANSCE), Los Alamos are reported here.

  1. Total reaction cross sections from elastic {alpha}-nucleus scattering angular distributions around the Coulomb barrier

    SciTech Connect

    Mohr, P.; Galaviz, D.; Fueloep, Zs.; Gyuerky, Gy.; Kiss, G. G.; Somorjai, E.

    2010-10-15

    The total reaction cross section {sigma}{sub reac} is a valuable measure for the prediction of {alpha}-induced reaction cross sections within the statistical model and for the comparison of scattering of tightly bound projectiles to weakly bound and exotic projectiles. Here we provide the total reaction cross sections {sigma}{sub reac} derived from our previously published angular distributions of elastic {alpha}-nucleus scattering on {sup 89}Y, {sup 92}Mo, {sup 112,124}Sn, and {sup 144}Sm at energies around the Coulomb barrier.

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

    NASA Astrophysics Data System (ADS)

    Sargsyan, V. V.; Adamian, G. G.; Antonenko, N. V.; Diaz-Torres, A.; Gomes, P. R. S.; Lenske, H.

    2016-07-01

    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.

  3. Actinide cross sections from the reaction of sup 13 C with sup 254 Es sup g

    SciTech Connect

    Moody, K.J.; Lougheed, R.W.; Dougan, R.J.; Hulet, E.K.; Wild, J.F.; Summerer, K.; Hahn, R.L.; Aarle, J.v.; Bethune, G.R. )

    1990-01-01

    We have measured cross sections for the formation of actinide transfer products in the reaction of 72-MeV {sup 13}C projectiles with {sup 254}Es{sup {ital g}} targets. The pattern of nuclide yields is similar to those observed in the reactions of heavier ions with {sup 254}Es{sup {ital g}}. We have constructed the primary element yields from these results and show that the total cross section for transfer reactions is 58 mb. The total reaction cross section is about 300 mb. Lawrencium isotopes are formed with larger cross sections than are consistent with the trends of the transfer-product distributions; we explain this in terms of massive transfer, and model the lawrencium yields with an evaporation code.

  4. Energy and Mass-Number Dependence of Hadron-Nucleus Total Reaction Cross Sections

    NASA Astrophysics Data System (ADS)

    Kohama, Akihisa; Iida, Kei; Oyamatsu, Kazuhiro

    2016-09-01

    We thoroughly investigate how proton-nucleus total reaction cross sections depend on the target mass number A and the proton incident energy. In doing so, we systematically analyze nuclear reaction data that are sensitive to nuclear size, namely, proton-nucleus total reaction cross sections and differential elastic cross sections, using a phenomenological black-sphere approximation of nuclei that we are developing. In this framework, the radius of the black sphere is found to be a useful length scale that simultaneously accounts for the observed proton-nucleus total reaction cross section and first diffraction peak in the proton elastic differential cross section. This framework, which is shown here to be applicable to antiprotons, is expected to be applicable to any kind of projectile that is strongly attenuated in the nucleus. On the basis of a cross-section formula constructed within this framework, we find that a less familiar A1/6 dependence plays a crucial role in describing the energy dependence of proton-nucleus total reaction cross sections.

  5. Heavy actinide cross sections in the /sup 238/U + /sup 248/Cm reaction

    SciTech Connect

    Kratz, J V; Bruechle, W; Gaeggeler, H

    1981-01-01

    Cross sections for the production of Cf, Es, Fm, and Md isotopes in the reactions of 7.4 MeV/u /sup 238/U-ions with /sup 248/Cm targets are presented and discussed. Cross sections for the formation of heavy actinides in the reactions of 7.5 MeV/u /sup 136/Xe and /sup 238/U-projectiles with /sup 238/U-targets are presented for comparison. (WHK)

  6. Partial (gamma)-Ray Cross Sections for the Reaction 239Pu(n,2n(gamma)i) and the 239Pu(n,2n) Cross Section

    SciTech Connect

    Beacker, J.A.; Bernstein, L.A.; Younes, W.; McNabb, D.P.; Garrett, P.E.; Archer, D.; McGrath, C.A.; Stoyer, M.A.; Chen, H.; Ormand, W.E.; Nelson, R.O.; Chadwick, M.B.; Johns, G.D.; Drake, D.; Young, P.G.; Devlin, M.; Fotiades, N.; Wilburn, W.S.

    2001-09-14

    Absolute partial {gamma}-ray cross sections for production of discrete {gamma} rays in the {sup 239}Pu(n,2n{gamma}i){sup 238}Pu reaction have been measured. The experiments were performed at LANSCE/WNR on the 60R flight line. Reaction {gamma}-rays were measured using the large-scale Compton-suppressed array of Ge detectors, GEANIE. The motivation for this experiment, an overview of the partial {gamma}-ray cross-section measurement, and an introduction to the main experimental issues will be presented. The energy resolution of the Ge detectors allowed identification of reaction {gamma} rays above the background of sample radioactivity and fission {gamma} rays. The use of planar Ge detectors with their reduced sensitivity to neutron interactions and improved line shape was also important to the success of this experiment. Absolute partial {gamma}-ray cross sections are presented for the 6{sub 1}{sup +} {yields} 4{sub 1}{sup +} member of the ground state rotational band in {sup 238}Pu, together with miscellaneous other {gamma}-ray partial cross sections. The n,2n reaction cross section shape and magnitude as a function of neutron energy was extracted from these partial cross sections using nuclear modeling (enhanced Hauser-Feshbach) to relate partial {gamma}-ray cross sections to the n,2n cross section. The critical nuclear modeling issue is the ratio of a partial cross section to the reaction channel cross section, and not the prediction of the absolute magnitude.

  7. Isotopic dependence of fusion cross sections in reactions with heavy nuclei

    NASA Astrophysics Data System (ADS)

    Adamian, G. G.; Antonenko, N. V.; Scheid, W.

    2000-09-01

    The dependence of fusion cross section on the isotopic composition of colliding nuclei is analysed within the dinuclear system concept for compound nucleus formation. Probabilities of fusion and surviving probabilities, ingredients of the evaporation residue cross sections, depend decisively on the neutron numbers of the dinuclear system. Evaporation residue cross sections for the production of actinides and superheavy nuclei, listed in table form, are discussed and compared with existing experimental data. In the Pb-based reactions neutron-rich radioactive projectiles are shown to lead to similar fusion cross sections as stable projectiles.

  8. Hot fusion-evaporation cross sections of 44Ca-induced reactions with lanthanide targets

    NASA Astrophysics Data System (ADS)

    Werke, T. A.; Mayorov, D. A.; Alfonso, M. C.; Tereshatov, E. E.; Folden, C. M.

    2015-11-01

    Background: Previously reported cross sections of 45Sc-induced reactions with lanthanide targets are much smaller than 48Ca-induced reactions on the same targets. 44Ca is one proton removed from 45Sc and could be used to produce nuclei with a relative neutron content between those produced in the 45Sc- and 48Ca-induced reactions. Purpose: As part of a systematic investigation of fusion-evaporation reactions, cross sections of 44Ca-induced reactions on lanthanide targets were measured. These results are compared to available data for 48Ca- and 45Sc-induced fusion-evaporation cross sections on the same lanthanide targets. Collectively, these data provide insight into the importance of the survival against fission of excited compound nuclei produced near spherical shell closures. Methods: A beam of 6+Ca at an energy of ≈5 MeV /u was delivered by the K500 superconducting cyclotron at the Cyclotron Institute at Texas A&M University. The desired evaporation residues were selected by the Momentum Achromat Recoil Spectrometer and identified via their characteristic α -decay energies. Excitation functions for the 44Ca+158Gd ,159Tb, and 162Dy reactions were measured at five or more energies each. A theoretical model was employed to study the fusion-evaporation process. Results: The 44Ca-induced reactions have x n cross sections that are two orders of magnitude larger than 45Sc-induced reactions but two orders of magnitude smaller than 48Ca-induced reactions on the same targets. Proton emission competes effectively with neutron emission for the 44Ca+159Tb and 162Dy reactions. The maximum 4 n cross sections in the 44Ca+158Gd ,159Tb, and 162Dy reactions were 2100 ± 230 ,230 ± 20 , and 130 ±20 μ b , respectively. The 44Ca+158Gd and 159Tb cross sections are in good agreement with the respective cross bombardments of 48Ca+154Gd and 45Sc+158Gd once differences in capture cross sections and compound nucleus formation probabilities are corrected for. Conclusions: Excitation

  9. Measurements of nuclear reaction cross sections for 183, 184W + 238U near the interaction barrier

    NASA Astrophysics Data System (ADS)

    Himmele, G.; Backe, H.; Butler, P. A.; Habs, D.; Metag, V.; Specht, H. J.; Wilhelmy, J. B.

    1983-08-01

    The cross sections for inelastic scattering, nucleon transfer and transfer-induced fission have been measured for 184W + 238U as a function of bombarding energy near the interaction barrier. The inelastic scattering cross section for 183W + 238U has also been measured at one energy. The two- nucleon and one-nucleon transfer cross sections, for neutron stripping at least, are similar in magnitude which suggests a substantial enhancement for the two-nucleon transfers. The probabilities for fission following the transfer reactions show in some cases strong dependence on bombarding energy, which demonstrates that simultaneous Coulomb excitation plays an important part in transfer reactions between very heavy ions.

  10. Production Cross Sections for Synthesis of Nuclides with Z = 118 IN Large Mass Transfer Reactions

    NASA Astrophysics Data System (ADS)

    Wang, Nan; Jin, Xin; Yang, Shuang; Zhao, En-Guang

    The production cross sections for the synthesis of superheavy nuclei with charge number 118 are studied with the di-nuclear system model with dynamical potential surface (DNS-DyPES model). The dynamical potential energy surface (PES) and the fusion probabilities for 48Ca bombarding Cf nuclei reactions are studied. By multiplying the capture cross section, fusion probability and survival probability, the evaporation residue(ER) cross sections for superheavy nuclei with Z = 118 are obtained. And the excitation functions for the reactions with a mixture target of Cf isotopes are also shown.

  11. Capture cross sections for the near symmetric {sup 124}Sn+{sup 96}Zr reaction

    SciTech Connect

    Vinodkumar, A. M.; Loveland, W.; Sprunger, P. H.; Peterson, D.; Liang, J. F.; Shapira, D.; Varner, R. L.; Gross, C. J.; Kolata, J. J.

    2006-12-15

    Capture-fission cross sections were measured for the near symmetric reaction between the massive nuclei {sup 124}Sn and {sup 96}Zr for center of mass energies from 195 to 265 MeV. Coincident fission fragments were detected and separated from elastic and deep inelastic scattering products by angle/energy/mass conditions. The measured capture cross sections agree quite well with calculations using the dinuclear system (DNS) model. The DNS model also predicts the fusion cross section for this reaction with a fusion barrier height of 208.0 MeV. The deduced extra push energy, corresponding to this barrier height, differs from that deduced from evaporation residue measurements.

  12. A New Method for Estimating Neutron Reaction Cross Sections Based on Wick's Limit

    SciTech Connect

    Dietrich, F S; Anderson, J D; Bauer, R W; Grimes, S M

    2004-10-13

    Wick's limit is an inequality that relates the zero-degree differential elastic scattering cross section to the total cross section. The deviation of Wick's limit from an exact equality is small over a wide range of incident energies and target masses. Under these circumstances we show that Wick's limit can be used to correlate the uncertainties in the two terms of the reaction (nonelastic) cross section expressed as the difference between the total and angle-integrated elastic cross sections. When suitable elastic angular distributions are available, we show that the reaction cross section may be obtained with small errors (typically 1.5-3%). Examples are shown for {sup 208P}b, {sup 54-56}Fe, {sup 232}Th, and {sup 238}U.

  13. A New Method for Estimating Neutron Reaction Cross Sections Based on Wick's Limit

    SciTech Connect

    Dietrich, F.S.; Anderson, J.D.; Bauer, R.W.; Grimes, S.M.

    2005-05-24

    Wick's limit is an inequality that relates the zero-degree differential elastic scattering cross section to the total cross section. The deviation of Wick's limit from an exact equality is small over a wide range of incident energies and target masses. Under these circumstances we show that Wick's limit can be used to correlate the uncertainties in the two terms of the reaction (nonelastic) cross section expressed as the difference between the total and angle-integrated elastic cross sections. When suitable elastic angular distributions are available, we show that the reaction cross section may be obtained with small errors (typically 1.5-3%). Examples are shown for 208Pb, 54-56Fe, 232Th, and 238U.

  14. Ion dipole capture cross sections at low ion and rotational energies - Comparison of integrated capture cross sections with reaction cross sections for NH3 and H2O parent-ion collisions.

    NASA Technical Reports Server (NTRS)

    Dugan, J. V., Jr.; Canright, R. B., Jr.

    1972-01-01

    The numerical capture cross section is calculated from the capture ratio, defined as the fraction of trajectories reaching a prescribed minimum separation of 3 A. The calculated capture cross sections for a rotational temperature of 77 K suggest large reaction cross sections in 80 K experiments for the large dipole-moment target, methyl cyanide.

  15. Calculation of cross sections for binary reactions between heavy ion projectiles and heavy actinide targets

    SciTech Connect

    Hoffman, D.C.; Hoffman, M.M.

    1990-11-01

    The computer program, described in this report, is identified as PWAVED5. It was developed to calculate cross sections for nucleon transfer reactions in low energy heavy ion bombardments. The objective was to calculate cross sections that agree with experimental results for ions of different charge and mass and to develop a predictive capability. It was undertaken because previous heavy ion calculations, for which programs were readily available, appeared to focus primarily on reactions resulting in compound nucleus formation and were not particularly applicable to calculations of binary reaction cross sections at low interaction energies. There are to principal areas in which this computation differs from several other partial wave calculations of heavy-ion reaction cross sections. First, this program is designed specifically to calculate cross sections for nucleon exchange interactions and to exclude interactions that are expected to result in fusion of the two nuclei. A second major difference in this calculation is the use of a statistical distribution to assign the total interaction cross section to individual final mass states.

  16. Reaction cross sections on carbon for neutron energies from 11. 5 to 19 MeV

    SciTech Connect

    Antolkovic, B. ); Dietze, G.; Klein, H. )

    1991-01-01

    This paper reports on neutron-induced reaction cross sections for carbon measured in the 11.5- to 19-MeV energy range. The response of an NE-213 scintillation detector is measured in steps of at least 0.5 MeV for monoenergetic neutrons, applying suitable time-of-flight techniques, and compared with Monte Carlo simulations. The total cross sections of all reactions with charged particles (except carbon recoil protons) in the exit channel are determined with respect to the n-p scattering cross section. In addition, the {sup 12}C(n,n{prime}3{alpha}) reaction is investigated for neutron energies of 11.9, 12.9, 14.0, 14.8, 17.0, and 19.0 MeV using the nuclear emulsion technique. As it is kinematically complete, this measurement yields the total and partial cross sections for the various channels of the {sup 12}C(n,n{prime}3{alpha}) reaction. The experimental data show deviations of up to {plus minus}25% from those recommended in ENDF/B-V, while a recent evaluation by Axton is partially confirmed. Reasonable agreement is found with most of the recent scattering experiments; thus, this data set represents a valuable constraint for further evaluations. The analysis performed, however, has shown that additional data from some partial reaction cross sections are needed.

  17. Estimating Reaction Cross Sections from Measured (Gamma)-Ray Yields: The 238U(n,2n) and 239Pu(n,2n) Cross Sections

    SciTech Connect

    Younes, W

    2002-11-18

    A procedure is presented to deduce the reaction-channel cross section from measured partial {gamma}-ray cross sections. In its simplest form, the procedure consists in adding complementary measured and calculated contributions to produce the channel cross section. A matrix formalism is introduced to provide a rigorous framework for this approach. The formalism is illustrated using a fictitious product nucleus with a simple level scheme, and a general algorithm is presented to process any level scheme. In order to circumvent the cumbersome algebra that can arise in the matrix formalism, a more intuitive graphical procedure is introduced to obtain the same reaction cross-section estimate. The features and limitations of the method are discussed, and the technique is applied to extract the {sup 235}U (n,2n) and {sup 239}Pu(n,2n) cross sections from experimental partial {gamma}-ray cross sections, coupled with (enhanced) Hauser-Feshbach calculations.

  18. Neutron-induced fission cross sections of short-lived actinides with the surrogate reaction method.

    SciTech Connect

    Kessedijian, G.; Jurado, B.; Aiche, M.; Barreau, G.; Bidaud, A.; Czajkowski, S.; Dassie, D.; Haas, B.; Mathieu, L.; Audouin, L.; Capellan, N.; Tassan-Got, L.; Wilson, J. N.; Berthoumieux, E.; Gunsing, F.; Theisen, Ch.; Serot, O.; Bauge, E.; Ahmad, I.; Greene, J. P.; Janssens, R. V. F.

    2010-09-13

    Neutron-induced fission cross sections for {sup 242,243}Cm and {sup 241}Am have been obtained with the surrogate reaction method. Recent results for the neutron-induced cross section of {sup 243}Cm are questioned by the present data. For the first time, the {sup 242}Cm cross section has been determined up to the onset of second-chance fission. The good agreement at the lowest excitation energies between the present results and the existing neutron-induced data indicates that the distributions in spin and parity of states populated with both techniques are similar.

  19. Total reaction cross sections in CEM and MCNP6 at intermediate energies

    NASA Astrophysics Data System (ADS)

    Kerby, Leslie M.; Mashnik, Stepan G.

    2015-08-01

    Accurate total reaction cross section models are important to achieving reliable predictions from spallation and transport codes. The latest version of the Cascade Exciton Model (CEM) as incorporated in the code CEM03.03, and the Monte Carlo N-Particle transport code (MCNP6), both developed at Los Alamos National Laboratory (LANL), each use such cross sections. Having accurate total reaction cross section models in the intermediate energy region (∼ 50 MeV to ∼ 5 GeV) is very important for different applications, including analysis of space environments, use in medical physics, and accelerator design, to name just a few. The current inverse cross sections used in the preequilibrium and evaporation stages of CEM are based on the Dostrovsky et al. model, published in 1959. Better cross section models are available now. Implementing better cross section models in CEM and MCNP6 should yield improved predictions for particle spectra and total production cross sections, among other results. Our current results indicate this is, in fact, the case.

  20. Total reaction cross sections in CEM and MCNP6 at intermediate energies

    DOE PAGESBeta

    Kerby, Leslie M.; Mashnik, Stepan G.

    2015-05-14

    Accurate total reaction cross section models are important to achieving reliable predictions from spallation and transport codes. The latest version of the Cascade Exciton Model (CEM) as incorporated in the code CEM03.03, and the Monte Carlo N-Particle transport code (MCNP6), both developed at Los Alamos National Laboratory (LANL), each use such cross sections. Having accurate total reaction cross section models in the intermediate energy region (50 MeV to 5 GeV) is very important for different applications, including analysis of space environments, use in medical physics, and accelerator design, to name just a few. The current inverse cross sections used inmore » the preequilibrium and evaporation stages of CEM are based on the Dostrovsky et al. model, published in 1959. Better cross section models are now available. Implementing better cross section models in CEM and MCNP6 should yield improved predictions for particle spectra and total production cross sections, among other results.« less

  1. Cross sections for deeply inelastic transfer reactions induced by heavy ions in rare-earth targets

    NASA Astrophysics Data System (ADS)

    Rivet, M. F.; Bimbot, R.; Gardès, D.; Fleury, A.; Hubert, F.; Llabador, Y.

    1982-04-01

    Cross sections have been measured for deeply inelastic transfer reactions leading to the production of several radio-nuclides. Rare-earth targets were used and the projectiles were Ar, Cr, Fe and Cu ions. The reactions studied corresponded to transfers of two to nine protons and variable numbers of neutrons. The results obtained were used to study the evolution of some characteristics of these reactions, such as integrated cross sections and widths of the isotopic distributions, versus incident mass and transferred mass. These results confirm that mass transfer is driven by the potential energy of the composite system. The decrease of cross sections for increasing charge transfer may be quantitatively explained by assuming thermodynamical equilibrium of the mass asymmetry degree of freedom.

  2. PRECO-D2: program for calculating preequilibrium and direct reaction double differential cross sections

    SciTech Connect

    Kalbach, C.

    1985-02-01

    The code PRECO-D2 uses the exciton model for preequilibrium nuclear reactions to describe the emission of particles with mass numbers of 1 to 4 from an equilibrating composite nucleus. A distinction is made between open and closed configurations in this system and between the multi-step direct (MSD) and multi-step compound (MSC) components of the preequilibrium cross section. Additional MSD components are calculated semi-empirically to account for direct nucleon transfer reactions and direct knockout processes involving cluster degrees of freedom. Evaporation from the equilibrated composite nucleus is included in the full MSC cross section. Output of energy differential and double differential cross sections is provided for the first particle emitted from the composite system. Multiple particle emission is not considered. This report describes the reaction models used in writing PRECO-D2 and explains the organization and utilization of the code. 21 refs.

  3. Deformation effect on total reaction cross sections for neutron-rich Ne isotopes

    SciTech Connect

    Minomo, Kosho; Sumi, Takenori; Ogata, Kazuyuki; Shimizu, Yoshifumi R.; Yahiro, Masanobu; Kimura, Masaaki

    2011-09-15

    The isotope dependence of measured reaction cross sections in the scattering of {sup 28-32}Ne isotopes from a {sup 12}C target at 240 MeV/nucleon is analyzed by the double-folding model with the Melbourne g matrix. The density of the projectile is calculated by the mean-field model with the deformed Woods-Saxon potential. The deformation is evaluated by antisymmetrized molecular dynamics. The deformation of the projectile enhances calculated reaction cross sections to the measured values.

  4. Elastic scattering and total reaction cross section for the 6He + 27Al system

    NASA Astrophysics Data System (ADS)

    Benjamim, E. A.; Lépine-Szily, A.; Mendes Junior, D. R.; Lichtenthäler, R.; Guimarães, V.; Gomes, P. R. S.; Chamon, L. C.; Hussein, M. S.; Moro, A. M.; Arazi, A.; Padron, I.; Alcantara Nuñez, J.; Assunção, M.; Barioni, A.; Camargo, O.; Denke, R. Z.; de Faria, P. N.; Pires, K. C. C.

    2007-03-01

    The elastic scattering of the radioactive halo nucleus 6He on 27Al target was measured at four energies close to the Coulomb barrier using the RIBRAS (Radioactive Ion Beams in Brazil) facility. The São Paulo Potential (SPP) was used and its diffuseness and imaginary strength were adjusted to fit the elastic scattering angular distributions. Reaction cross-sections were extracted from the optical model fits. The reduced reaction cross-sections of 6He on 27Al are similar to those for stable, weakly bound projectiles as 6,7Li, 9Be and larger than stable, tightly bound projectile as 16O on 27Al.

  5. Cross Section Calculations of Deuteron-induced Reactions Using the Extended CCONE Code

    NASA Astrophysics Data System (ADS)

    Nakayama, S.; Araki, S.; Watanabe, Y.; Iwamoto, O.; Ye, T.; Ogata, K.

    2014-04-01

    We have extended the CCONE code to make it possible to calculate cross sections for deuteron-induced reactions. Elastic breakup and stripping reactions to continuum are calculated using another codes based on the Continuum-Discretized Coupled-Channels theory (CDCC) and the Glauber model, respectively, and the calculated results are inputted to the CCONE code as direct reaction components. Statistical decay from compound nuclei formed by nucleon stripping and deuteron absorption is calculated with the exciton and Hauser-Feshbach models implemented in the original CCONE code. The extended CCONE code is applied to analyses of deuteron-induced reactions on 27Al and 58Ni. CDCC calculations for deuteron elastic scattering show good agreement with the experimental data at incident energies of several tens of MeV. The calculated double-differential (d,xp) cross sections reproduce the measured ones at forward angles for incident energies of 56 and 100 MeV fairly well.

  6. Activation cross sections of proton induced nuclear reactions on palladium up to 80MeV.

    PubMed

    Tárkányi, F; Ditrói, F; Takács, S; Csikai, J; Hermanne, A; Uddin, M S; Baba, M

    2016-08-01

    Activation cross sections of proton induced nuclear reactions on palladium were measured up to 80MeV by using the stacked foil irradiation technique and gamma ray spectrometry. The beam intensity, the incident energy and the energy degradation were controlled by a method based on flux constancy via normalization to the excitation functions of monitor reactions measured in parallel. Excitation functions for direct and cumulative cross-sections were measured for the production of (104m,104g,105g,106m,110m)Ag, (100,101)Pd, (99m,99g,100,101m,101g,102m,102g,105)Rh and (103,97)Ru radioisotopes. The cross section data were compared with the theoretical predictions of TENDL-2014 and -2015 libraries. For practical applications thick target yields were derived from the measured excitation functions. Application in the field of medical radionuclide production is shortly discussed. PMID:27235887

  7. Absolute state-selected total cross sections for the O(+)(4S) + CO2 reactions

    NASA Astrophysics Data System (ADS)

    Flesch, G. D.; Ng, C. Y.

    1991-12-01

    Results are presented on measurements of absolute state-selected total cross sections for O2(+), CO2(+), CO(+), and C(+) produced in the reaction between O(+)(4S) and CO2, which were conducted in the center-of-mass collision energy (Ecm) range of 0.2-150 eV. It was found that, with increasing collisional energy, the cross section of O2(+) dropped off rapidly and became essentially zero at Ecm above 3 eV. The dependence of O2(+) cross section on the Ecm is consistent with a collision complex mechanism for the reaction between O(+)(4S) and CO2 yielding CO2(+) + O. The values for O2(+) obtained in this experiment were significantly higher than those reported by Rutherford and Vroom (1976).

  8. A new closed form expression for the total reaction cross-section of heavy ions

    SciTech Connect

    Rego, R.A. ); Hussein, M.S. )

    1989-01-01

    A new analytical expression for the H1 total reaction cross-section which exhibits that macroscopic features of the transparency factor is derived. Comparison with optical model calculation are made for the /sup 12/C + /sup 208/Pb and /sup 16/O + /sup 208/Pb at several energies.

  9. Determining Cross Sections for Reactions on Unstable Nuclei: A Consideration of Indirect Approaches

    SciTech Connect

    Escher, J; Dietrich, F S

    2005-05-24

    An indirect method for determining cross sections for reactions proceeding through a compound nucleus is presented. The appropriate theoretical framework for applications of this method is reviewed and theoretical and experimental challenges that need to be addressed in applications of the method are outlined. Two approximations are considered and their advantages and limitations are discussed.

  10. Determining Cross Sections for Reactions on Unstable Nuclei: A Consideration of Indirect Approaches

    SciTech Connect

    Escher, J.; Dietrich, F.S.

    2005-10-14

    An indirect method for determining cross sections for reactions proceeding through a compound nucleus is presented. The appropriate theoretical framework for applications of this method is reviewed and theoretical and experimental challenges that need to be addressed in applications of the method are outlined. Two approximations are considered and their advantages and limitations are discussed.

  11. High resolution measurements of the Am241(n,2n) reaction cross section

    NASA Astrophysics Data System (ADS)

    Sage, C.; Semkova, V.; Bouland, O.; Dessagne, P.; Fernandez, A.; Gunsing, F.; Nästren, C.; Noguère, G.; Ottmar, H.; Plompen, A. J. M.; Romain, P.; Rudolf, G.; Somers, J.; Wastin, F.

    2010-06-01

    Measurements of the Am241(n,2n) reaction cross section have been performed at the Joint Research Centre (JRC) Geel in the frame of a collaboration between the European Commission (EC) JRC and French laboratories from CNRS and the Commissariat à L’Energie Atomique (CEA) Cadarache. Raw material coming from the Atalante facility of CEA Marcoule has been transformed by JRC Karlsruhe into suitable Am241O2 samples embedded in Al2O3 matrices specifically designed for these measurements. The irradiations were carried out at the 7-MV Van de Graaff accelerator. The Am241(n,2n) reaction cross section was determined relative to the Al27(n,α)Na24 standard cross section. The measurements were performed in four sessions, using quasi-mono-energetic neutrons with energies ranging from 8 to 21 MeV produced via the H2(d,n)He3 and the H3(d,n)He4 reactions. The induced activity was measured by standard γ-ray spectrometry using a high-purity germanium detector. Below 15 MeV, the present results are in agreement with data obtained earlier. Above 15 MeV, these measurements allowed the experimental investigation of the Am241(n,2n) reaction cross section for the first time. The present data are in good agreement with predictions obtained with the talys code that uses an optical and fission model developed at CEA.

  12. (γ,2n) Reaction Cross Section Calculations on Several Structural Fusion Materials

    NASA Astrophysics Data System (ADS)

    Kaplan, A.; Özdoğan, H.; Aydın, A.; Tel, E.

    2013-08-01

    In this study, the theoretical photo-neutron cross-sections produced by (γ,2n) reactions for several structural fusion materials such as 51V, 55Mn, 58Ni, 90,91,92,94Zr, and 181Ta have been carried out for incident photon energies up to 40 MeV. Reaction cross-sections as a function of photon energy have been calculated theoretically using the PCROSS and TALYS 1.2 computer codes. TALYS 1.2 default and pre-equilibrium models have been used to calculate the pre-equilibrium photo-neutron cross-sections. For the reaction equilibrium component, PCROSS Weisskopf-Ewing model calculations have been preferred. The calculated results have been compared with each other and against the experimental data in the existing databases EXFOR. Generally, TALYS 1.2 default and pre-equilibrium model cross-section calculations are in good agreement with the experimental data for all reactions along the incident photon energy in this study. Pre-equilibrium option can be recommended, if experimental data are not available or are unlikely to be produced due to the experimental difficulty.

  13. Cross-section measurements of neutron threshold reactions in various materials

    NASA Astrophysics Data System (ADS)

    Vrzalová, J.; Svoboda, O.; Kugler, A.; Suchopár, M.; Wagner, V.

    As members of international collaboration "Energy and Transmutation of radioactive Waste" we routinely use (n,xn) threshold reactions in various materials to measure high energy neutron flux from spallation reactions. The cross-sections of many reactions important for our activation detectors are missing. To improve situation, we studied the neutron cross-sections using different quasi-monoenergetic neutron sources based on proton reaction on 7Li target. The measurements were performed in Nuclear Physics Institute of the Academy of Sciences of the Czech Republic in Řež near Prague and in The Svedberg Laboratory in Uppsala (Sweden). We used neutron energies 17, 22, 30 and 35 MeV from the quasi-monoenergetic neutron source in Řež and neutron energies 22, 47 and 94 MeV in Uppsala. The last experiment was carried out in February 2010 in Uppsala using neutron energies 59, 66, 72 and 89 MeV. The study of neutron threshold reactions in yttrium was performed first time during this irradiation. We have developed procedure for the subtraction of contribution of the background neutrons. We studied various materials in the form of thin foils and observed good agreement with the data in EXFOR database and also with the calculations performed in deterministic code TALYS. Many cross-sections were measured in the energy regions where no experimental data are available so far.

  14. Calculations of Proton Emission Cross Sections in Deuteron Induced Reactions of Some Fusion Structural Materials

    NASA Astrophysics Data System (ADS)

    Yiğit, M.; Tel, E.; Tanır, G.

    2013-06-01

    The growing demands for energy consumption have led to the increase of the research and development activities on new energy sources. Fusion energy has the highest potential to become a very safe, clean and abundant energy source for the future. To get energy from fusion are needed for development of fusion reactor technology. Particularly, the design and development of international facilities as International Thermonuclear Experimental Reactor and International Fusion Material Irradiation Facility requires for the cross-section data of deuteron induced reactions. Moreover, the selection of fusion structural materials are an indispensable component for this technology. Therefore, the cross-section data of deuteron induced reactions on fusion structural materials are of great importance for development of fusion reactor technology. In this study, reaction model calculations of the cross sections of deuteron induced reactions on structural fusion materials such as 27Al, 59Co, 55Mn, 50Cr, 54Cr, 64Ni, 109Ag, 184W and 186W have been carried out for incident energies up to 50 MeV. In these calculations, the pre-equilibrium and equilibrium effects for ( d, p) stripping reactions have been investigated. The pre-equilibrium calculations involve the new evaluated the geometry dependent hybrid model and hybrid model. Equilibrium effects are calculated according to the Weisskopf-Ewing model. In the calculations the program code ALICE/ASH was used. The calculated results are discussed and compared with the experimental data taken from the literature.

  15. Cross sections calculated for cold fusion reactions for producing superheavy nuclei

    SciTech Connect

    Smolanczuk, Robert

    2008-08-15

    We propose a handy formula for calculating the formation cross sections for optimal bombarding energies for transactinides (superheavy elements). By means of the proposed formula the cross sections for asymmetric and symmetric cold fusion reactions (one-neutron-out reactions) are calculated. The fusion barrier and its position are calculated by using the folding heavy-ion potential that for spherical reaction partners has the form of a seventh-order polynomial of the radial coordinate with built-in dependence on the thickness of the nuclear surface, as well as on the separation energy of the least bound nucleon. Possibilities of further experimental exploitation of cold fusion in producing the superheavy nuclei are briefly discussed.

  16. A Study on 19F( n,α) Reaction Cross Section

    NASA Astrophysics Data System (ADS)

    Uğur, F. A.; Tel, E.; Gökçe, A. A.

    2013-06-01

    In this study, cross sections of neutron induced reactions have been investigated for fluorine target nucleus. The calculations have been made on the excitation functions of 19F ( n,α), 19F( n,xα) reactions. Fluorine (F) and its molten salt compounds (LiF) can serve as a coolant which can be used at high temperatures without reaching a high vapor pressure and also the molten salt compounds are also a good neutron moderator. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve the full exciton model and the cascade exciton model. The equilibrium effects are calculated according to the Weisskopf-Ewing model. Also in the present work, reaction cross sections have calculated by using evaluated empirical formulas developed by Tel et al. at 14-15 MeV energy. The obtained results have been discussed and compared with the available experimental data.

  17. Studies of combustion reactions at the state-resolved differential cross section level

    SciTech Connect

    Houston, P.L.; Suits, A.G.; Bontuyan, L.S.; Whitaker, B.J.

    1993-12-01

    State-resolved differential reaction cross sections provide perhaps the most detailed information about the mechanism of a chemical reaction, but heretofore they have been extremely difficult to measure. This program explores a new technique for obtaining differential cross sections with product state resolution. The three-dimensional velocity distribution of state-selected reaction products is determined by ionizing the appropriate product, waiting for a delay while it recoils along the trajectory imparted by the reaction, and finally projecting the spatial distribution of ions onto a two dimensional screen using a pulsed electric field. Knowledge of the arrival time allows the ion position to be converted to a velocity, and the density of velocity projections can be inverted mathematically to provide the three-dimensional velocity distribution for the selected product. The main apparatus has been constructed and tested using photodissociations. The authors report here the first test results using crossed beams to investigate collisions between Ar and NO. Future research will both develop further the new technique and employ it to investigate methyl radical, formyl radical, and hydrogen atom reactions which are important in combustion processes. The authors intend specifically to characterize the reactions of CH{sub 3} with H{sub 2} and H{sub 2}CO; of HCO with O{sub 2}; and of H with CH{sub 4}, CO{sub 2}, and O{sub 2}.

  18. Isomeric cross section of the {sup 197}Au(n,2n) reaction

    SciTech Connect

    Tsinganis, A.; Diakaki, M.; Kokkoris, M.; Mara, E.; Papadopoulos, C. T.; Vlastou, R.; Lagoyannis, A.

    2011-02-15

    In the present work, the {sup 197}Au(n,2n) reaction cross section is experimentally determined relative to the {sup 27}Al(n,{alpha}){sup 24}Na reaction at incident neutron energies of 9.0-10.5 MeV by means of the activation technique. The quasimonoenergetic fast neutron beam was produced via the {sup 2}H(d,n){sup 3}He reaction at the 5.5-MV Tandem Van de Graaff accelerator at the National Centre of Scientific Research (NCSR) ''Demokritos'' and was studied to determine the contribution of background 'parasitic' neutrons using the multiple foil activation technique and the SULSA unfolding code. The cross sections for the population of the second isomeric state (12{sup -}) of {sup 196}Au and the sum of the ground (2{sup -}) and first isomeric state (5{sup -}) population cross sections were independently determined. Auxiliary Monte Carlo simulations were performed with the MCNP code. Theoretical calculations of the above cross sections in the 8-25 MeV region were carried out with the use of the STAPRE-F, EMPIRE, and TALYS codes, which were also compared in their implementation of the generalized superfluid model. The theoretical results are compared with previous work in the same mass region, and the strong dependence on the level scheme of the nuclei involved was revealed.

  19. Calculation of nuclear reaction cross sections on excited nuclei with the coupled-channels method

    SciTech Connect

    Kawano, T.; Talou, P.; Lynn, J. E.; Chadwick, M. B.; Madland, D. G.

    2009-08-15

    We calculate nuclear cross sections on excited nuclei in the fast neutron energy range. We partition the whole process into two contributions: the direct reaction part and the compound nuclear reactions. A coupled-channels method is used for calculating the direct transition of the nucleus from the initial excited state, which is a member of the ground-state rotational band, to the final ground and excited low-lying levels. This process is strongly affected by the channel coupling. The compound nuclear reactions on the excited state are calculated with the statistical Hauser-Feshbach model, with the transmission coefficients obtained from the coupled-channels calculation. The calculations are performed for a strongly deformed nucleus {sup 169}Tm, and selected cross sections for the ground and first excited states are compared. The calculation is also made for actinides to investigate possible modification to the fission cross section when the target is excited. It is shown that both the level coupling for the entrance channel, and the different target spin, change the fission cross section.

  20. Determination of Resonance Parameters and their Covariances from Neutron Induced Reaction Cross Section Data

    SciTech Connect

    Schillebeeckx, P.; Becker, B.; Danon, Y.; Guber, K.; Harada, H.; Heyse, J.; Junghans, A.R.; Kopecky, S.; Massimi, C.; Moxon, M.C.; Otuka, N.; Sirakov, I.; Volev, K.

    2012-12-15

    Cross section data in the resolved and unresolved resonance region are represented by nuclear reaction formalisms using parameters which are determined by fitting them to experimental data. Therefore, the quality of evaluated cross sections in the resonance region strongly depends on the experimental data used in the adjustment process and an assessment of the experimental covariance data is of primary importance in determining the accuracy of evaluated cross section data. In this contribution, uncertainty components of experimental observables resulting from total and reaction cross section experiments are quantified by identifying the metrological parameters involved in the measurement, data reduction and analysis process. In addition, different methods that can be applied to propagate the covariance of the experimental observables (i.e. transmission and reaction yields) to the covariance of the resonance parameters are discussed and compared. The methods being discussed are: conventional uncertainty propagation, Monte Carlo sampling and marginalization. It is demonstrated that the final covariance matrix of the resonance parameters not only strongly depends on the type of experimental observables used in the adjustment process, the experimental conditions and the characteristics of the resonance structure, but also on the method that is used to propagate the covariances. Finally, a special data reduction concept and format is presented, which offers the possibility to store the full covariance information of experimental data in the EXFOR library and provides the information required to perform a full covariance evaluation.

  1. Evaluation of the 93Nb(n,γ) Reaction Cross-Section

    NASA Astrophysics Data System (ADS)

    Zolotarev, Konstantin; Badikov, Sergei

    2016-02-01

    New evaluation of the 93Nb(n,γ)94Nb reaction cross-section important for retrospective reactor dosimetry was carried out. At neutron energies below 7.5 keV the evaluation is based on the experimental data. The results of measurements extracted from the EXFOR library were corrected (when necessary) to new recommended values of monitor reaction cross-sections and decay data. The resonance analysis of the 93Nb(n,γ) and the 93Nb(n,tot) reaction cross-sections was carried out within the Reich-Moore formalism. 48 new resonances were identified as compared to the Mughabghab systematics. In the energy range from 7.5 keV to 20 MeV the evaluation is based on the experimental data and theoretical model calculations. The recommended cross-sections and their covariances in this energy range were evaluated by an approximation of the experimental and calculated values with the PADE2 code. The new evaluation provides, essentially, better agreement with the experimental data and the recommended value of the resonance integral compared to other evaluations.

  2. Measurement of inelastic cross sections in relativistic deuteron-on-lead reactions

    SciTech Connect

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

    2010-10-15

    The inelastic cross section of deuterons hitting a lead target has been determined by the beam attenuation technique. A spallation neutron source based on a lead target was irradiated with 1.6- and 2.5-GeV deuterons. Solid-state nuclear track detectors as well as the activation method were used to obtain the neutron and proton distribution along the surface of the source. The attenuation coefficient was estimated by fitting the experimental data and taking into account the buildup effect and the beam attenuation. Using the attenuation coefficient, the interaction length and then the inelastic cross section of deuterons on lead reaction were determined.

  3. Transfer cross sections from reactions with /sup 254/Es as a target

    SciTech Connect

    Schadel, M.; Bruechle, W.; Bruegger, M.; Gaggeler, H.; Moody, K.J.; Schardt, D.; Suemmerer, K.; Hulet, E.K.; Dougan, A.D.; Dougan, R.J.

    1986-04-01

    We report radiochemically determined cross sections for the heaviest known actinides produced in transfer reactions of /sup 16,18/O and /sup 22/Ne with /sup 254/Es as a target. A comparison with data for similar transfers from /sup 248/Cm targets is made. Transfer cross sections are extrapolated for the production of the unknown, neutron-rich isotopes of elements 101 through 105, and the unique potential of /sup 254/Es as a target to make these exotic nuclei accessible is demonstrated.

  4. Code System to Calculate Nuclear Reaction Cross Sections by Evaporation Model.

    Energy Science and Technology Software Center (ESTSC)

    2000-11-27

    Version: 00 Both STAPRE and STAPREF are included in this package. STAPRE calculates energy-averaged cross sections for nuclear reactions with emission of particles and gamma rays and fission. The models employed are the evaporation model with inclusion of pre-equilibrium decay and a gamma-ray cascade model. Angular momentum and parity conservation are accounted for. Major improvement in the 1976 STAPRE program relates to level density approach, implemented in subroutine ZSTDE. Generalized superfluid model is incorporated, boltzman-gasmore » modeling of intrinsic state density and semi-empirical modeling of a few-quasiparticle effects in total level density at equilibrium and saddle deformations of actinide nuclei. In addition to the activation cross sections, particle and gamma-ray production spectra are calculated. Isomeric state populations and production cross sections for gamma rays from low excited levels are obtained, too. For fission a single or a double humped barrier may be chosen.« less

  5. Determination of Minor Actinides Fission Cross Sections by Means of Transfer Reactions

    NASA Astrophysics Data System (ADS)

    Aiche, M.; Barreau, G.; Boyer, S.; Czajkowski, S.; Dassié, D.; Grosjean, C.; Guiral, A.; Haas, B.; Jurado, B.; Osmanov, B.; Bauge, E.; Petit, M.; Berthoumieux, E.; Gunsing, F.; Perrot, L.; Theisen, C.; Michel-Sendis, F.; Billebaud, A.; Wilson, J. N.; Ahmad, I.; Greene, J. P.; Janssens, R. V. F.

    2006-04-01

    An inventive method that allows to determine neutron-induced cross sections of very short-lived minor actinides is presented. We have successfully applied this method, based on the use of transfer reactions, to 233Pa, a key nucleus in the 232Th-233U fuel cycle. A recent experiment using this technique has also been performed in order to obtain the neutron-induced fission cross sections of 242, 243, 244Cm and 241Am 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. Preliminary experimental results will be presented.

  6. Neutrino-Induced Neutral-Current Reaction Cross Sections for r-PROCESS Nuclei

    NASA Astrophysics Data System (ADS)

    Langanke, K.; Kolbe, E.

    2002-11-01

    Neutrino-induced reactions play an important role during and after the r-process, if the latter occurs in an environment with extreme neutrino fluxes such as the neutrino-driven wind model or neutron star mergers. Recently we have evaluated the charged-current neutrino-nucleus cross sections relevant for r-process simulations. We extend our approach here to the neutral-current cross sections. Our tabulation considers neutron-rich nuclei with neutron numbers N=41-135 and charge numbers Z=21-82 and lists total as well as partial neutron spallation cross sections. The calculations have been performed within the random phase approximation considering multipole transitions with J<=3 and both parities. The supernova neutrino spectrum is described by a Fermi-Dirac distribution with various temperature parameters between T=2.8 MeV and T=10 MeV and with the degeneracy parameters α=0 and α=3.

  7. New approach to analyzing and evaluating cross sections for partial photoneutron reactions

    SciTech Connect

    Varlamov, V. V. Ishkhanov, B. S.; Orlin, V. N.

    2012-11-15

    The presence of substantial systematic discrepancies between the results of different experiments devoted to determining cross sections for partial photoneutron reactions-first of all, ({gamma}, n), ({gamma}, 2n), and ({gamma}, 3n) reactions-is a strong motivation for studying the reliability and authenticity of these data and for developing methods for taking into account and removing the discrepancies in question. In order to solve the first problem, we introduce objective absolute criteria involving transitional photoneutron-multiplicity functions F{sub 1}, F{sub 2}, F{sub 3}, Horizontal-Ellipsis ; by definition, their values cannot exceed 1.0, 0.5, 0.33, Horizontal-Ellipsis , respectively. With the aim of solving the second problem, we propose a new experimental-theoretical approach. In this approach, reaction cross sections are evaluated by simultaneously employing experimental data on the cross section for the total photoneutron yield, {sigma}{sup expt}({gamma}, xn) = {sigma}{sup expt}({gamma}, n) + 2{sigma}{sup expt}({gamma}, 2n) + 3{sigma}{sup expt}({gamma}, 3n) + Horizontal-Ellipsis , which are free from drawbacks plaguing experimental methods for sorting neutrons in multiplicity, and the results obtained by calculating the functions F{sub theor}{sup 1}, F{sub theor}{sup 2}, F{sub theor}{sup 3}, Horizontal-Ellipsis on the basis of the modern model of photonuclear reactions. The reliability and authenticity of data on the cross sections for ({gamma}, n), ({gamma}, 2n), and ({gamma}, 3n) partial reactions-{sigma}{sup eval}({gamma}, in) = F{sub i}{sup theor}{sigma}{sup expt}({gamma}, xn)-were evaluated for the {sup 90}Zr, {sup 115}In, {sup 112,114,116,117,118,119,120,122,124}Sn, {sup 159}Tb, and {sup 197}Au nuclei.

  8. Towards rotationally state-resolved differential cross sections for the hydrogen exchange reaction

    SciTech Connect

    Vrakking, M.J.J.

    1992-11-01

    The hydrogen exchange reaction H + H[sub 2] [yields] H[sub 2] + H (and its isotopic variants) plays a pivotal role in chemical reaction dynamics. It is the only chemical reaction for which fully converged quantum scattering calculations have been carried out using a potential energy surface which is considered to be chemically accurate. To improve our ability to test the theory, a 'perfect experiment', measuring differential cross sections with complete specification of the reactant and product states, is called for. In this thesis, the design of an experiment is described that aims at achieving this goal for the D + H[sub 2] reaction. A crossed molecular beam arrangement is used, in which a photolytic D atom beam is crossed by a pulsed beam of H[sub 2] molecules. DH molecules formed in the D + H[sub 2] reaction are state-specifically ionized using Doppler-free (2+1) Resonance-Enhanced Multi-Photon Ionization (REMPI) and detected using a Position-sensitive microchannel plate detector. This detection technique has an unprecedented single shot detection sensitivity of 6.8 10[sup 3] molecules/cc. This thesis does not contain experimental results for the D + H[sub 2] reaction yet, but progress that has been made towards achieving this goal is reported. In addition, results are reported for a study of the Rydberg spectroscopy of the water molecule.

  9. Towards rotationally state-resolved differential cross sections for the hydrogen exchange reaction

    SciTech Connect

    Vrakking, M.J.J.

    1992-11-01

    The hydrogen exchange reaction H + H{sub 2} {yields} H{sub 2} + H (and its isotopic variants) plays a pivotal role in chemical reaction dynamics. It is the only chemical reaction for which fully converged quantum scattering calculations have been carried out using a potential energy surface which is considered to be chemically accurate. To improve our ability to test the theory, a `perfect experiment`, measuring differential cross sections with complete specification of the reactant and product states, is called for. In this thesis, the design of an experiment is described that aims at achieving this goal for the D + H{sub 2} reaction. A crossed molecular beam arrangement is used, in which a photolytic D atom beam is crossed by a pulsed beam of H{sub 2} molecules. DH molecules formed in the D + H{sub 2} reaction are state-specifically ionized using Doppler-free (2+1) Resonance-Enhanced Multi-Photon Ionization (REMPI) and detected using a Position-sensitive microchannel plate detector. This detection technique has an unprecedented single shot detection sensitivity of 6.8 10{sup 3} molecules/cc. This thesis does not contain experimental results for the D + H{sub 2} reaction yet, but progress that has been made towards achieving this goal is reported. In addition, results are reported for a study of the Rydberg spectroscopy of the water molecule.

  10. Estimation of (n,f) Cross-Sections by Measuring Reaction Probability Ratios

    SciTech Connect

    Plettner, C; Ai, H; Beausang, C W; Bernstein, L A; Ahle, L; Amro, H; Babilon, M; Burke, J T; Caggiano, J A; Casten, R F; Church, J A; Cooper, J R; Crider, B; Gurdal, G; Heinz, A; McCutchan, E A; Moody, K; Punyon, J A; Qian, J; Ressler, J J; Schiller, A; Williams, E; Younes, W

    2005-04-21

    Neutron-induced reaction cross-sections on unstable nuclei are inherently difficult to measure due to target activity and the low intensity of neutron beams. In an alternative approach, named the 'surrogate' technique, one measures the decay probability of the same compound nucleus produced using a stable beam on a stable target to estimate the neutron-induced reaction cross-section. As an extension of the surrogate method, in this paper they introduce a new technique of measuring the fission probabilities of two different compound nuclei as a ratio, which has the advantage of removing most of the systematic uncertainties. This method was benchmarked in this report by measuring the probability of deuteron-induced fission events in coincidence with protons, and forming the ratio P({sup 236}U(d,pf))/P({sup 238}U(d,pf)), which serves as a surrogate for the known cross-section ratio of {sup 236}U(n,f)/{sup 238}U(n,f). IN addition, the P({sup 238}U(d,d{prime}f))/P({sup 236}U(d,d{prime}f)) ratio as a surrogate for the {sup 237}U(n,f)/{sup 235}U(n,f) cross-section ratio was measured for the first time in an unprecedented range of excitation energies.

  11. The effect of halo nuclear density on reaction cross-section for light ion collision

    NASA Astrophysics Data System (ADS)

    Hassan, M. A. M.; Nour El-Din, M. S. M.; Ellithi, A.; Ismail, E.; Hosny, H.

    2015-08-01

    In the framework of the optical limit approximation (OLA), the reaction cross-section for halo nucleus — stable nucleus collision at intermediate energy, has been studied. The projectile nuclei are taken to be one-neutron halo (1NHP) and two-neutron halo (2NHP). The calculations are carried out for Gaussian-Gaussian (GG), Gaussian-Oscillator (GO), and Gaussian-2S (G2S) densities for each considered projectile. As a target, the stable nuclei in the range 4-28 of the mass number are used. An analytic expression of the phase shift function has been derived. The zero range approximation is considered in the calculations. Also, the in-medium effect is studied. The obtained results are analyzed and compared with the geometrical reaction cross-section and the available experimental data.

  12. Measurement of the 25Mg(α,n)28Si reaction cross section at LNL

    NASA Astrophysics Data System (ADS)

    Depalo, R.; Caciolli, A.; Marchi, T.; Appannababu, S.; Blasi, N.; Broggini, C.; Camera, F.; Cinausero, M.; Collanzuol, G.; Fabris, D.; Gramegna, F.; Kravchuk, V. L.; Leone, M.; Lombardi, A.; Mastinu, P.; Menegazzo, R.; Montagnoli, G.; Prete, G.; Rigato, V.; Rossi Alvarez, C.; Wieland, O.

    2014-03-01

    The detection of the 1809 keV emission line associated with the decay of 26Al in the interstellar medium provides a direct evidence of recent nucleosynthesis events in our galaxy. 26Al is thought to be mainly produced in massive stars, but in order to have a quantita- tive understanding of the 26Al distribution, the cross section of all the nuclear reactions involved in its production should be accurately known. A recent sensitivity study demonstrated that the 25Mg(α,n)28Si is the reaction with the strongest impact on the synthesis of 26Al during explosive Neon and Carbon burning [4]. In order to improve the experimental knowledge of the 25Mg(α,n)28Si cross section, a new direct measurement has been performed at Legnaro National Laboratories. The experimental setup, the data analysis and preliminary results are discussed.

  13. On the geometric nature of high energy nucleus-nucleus reaction cross sections

    NASA Technical Reports Server (NTRS)

    Townsend, L. W.; Wilson, J. W.; Bidasaria, H. B.

    1982-01-01

    Within the context of a high energy double-folding optical potential approximation to the exact nucleus-nucleus multiple-scattering series, eikonal scattering theory is used to investigate the validity of geometric reaction cross sections in relativistic heavy ion collisions. The potential used includes a finite range interaction and nuclear single-particle densities extracted from nuclear charge distributions by unfolding the finite proton charge distribution. Pauli correlation effects are also included in an approximate way. The sensitivity of the predictions to the assumed interaction, Pauli correlation approximation, and nuclear density distributions is investigated. These results are in agreement with early predictions concerning the geometric nature of relativistic heavy ion collisions and in disagreement with a recent analysis, utilizing the zero range approximation, which suggested otherwise. Reasons for the lack of agreement between the analyses are also presented. Finally, approximate applicability limits for geometric reaction cross sections are determined.

  14. Isomeric Cross-Section Study of Neutron-Induced Reactions on Ge

    SciTech Connect

    Vlastou, R.; Galanopoulos, S.; Papadopoulos, C. T.; Kokkoris, M.; Serris, M.; Lagoyannis, A.; Demetriou, P.

    2009-01-28

    The {sup 72}Ge(n,{alpha}){sup 69m}Zn, {sup 74}Ge(n,{alpha}){sup 71m}Zn, {sup 76}Ge(n,2n){sup 75g+m}Ge reaction cross sections have been measured from 9.6 to 11.4 MeV and studied, along with data from literature, within the frame of the statistical model using the code EMPIRE-II.

  15. Elastic scattering and total reaction cross section of {sup 6}He+{sup 120}Sn

    SciTech Connect

    Faria, P. N. de; Lichtenthaeler, R.; Pires, K. C. C.; Lepine-Szily, A.; Guimaraes, V.; Mendes, D. R. Jr.; Barioni, A.; Morcelle, V.; Morais, M. C.; Camargo, O. Jr.; Alcantara Nunez, J.; Moro, A. M.; Arazi, A.; Rodriguez-Gallardo, M.; Assuncao, M.

    2010-04-15

    The elastic scattering of {sup 6}He on {sup 120}Sn has been measured at four energies above the Coulomb barrier using the {sup 6}He beam produced at the RIBRAS (Radioactive Ion Beams in Brasil) facility. The elastic angular distributions have been analyzed with the optical model and three- and four-body continuum-discretized coupled-channels calculations. The total reaction cross sections have been derived and compared with other systems of similar masses.

  16. Nucleus-nucleus total reaction cross sections, and the nuclear interaction radius

    SciTech Connect

    Abu-Ibrahim, Badawy

    2011-04-15

    We study the nucleus-nucleus total reaction cross sections for stable nuclei, in the energy region from 30A MeV to about 1A GeV, and find them to be in proportion to ({radical}({sigma}{sub pp}{sup tot}Z{sub 1}{sup 2/3}+{sigma}{sub pn}{sup tot}N{sub 1}{sup 2/3})+{radical}({sigma}{sub pp}{sup tot}Z{sub 2}{sup 2/3}+{sigma}{sub pn}{sup tot}N{sub 2}{sup 2/3})) {sup 2} in the mass range 8 to 100. Also, we find a parameter-free relation that enables us to predict a total reaction cross section for any nucleus-nucleus within 10% uncertainty at most, using the experimental value of the total reaction cross section of a given nucleus-nucleus. The power of the relation is demonstrated by several examples. The energy dependence of the nuclear interaction radius is deduced; it is found to be almost constant in the energy range from about 200A MeV to about 1A GeV; in this energy range and for nuclei with N=Z, R{sub I}(A)=(1.14{+-}0.02)A{sup 1/3} fm.

  17. Bayesian Evaluation Including Covariance Matrices of Neutron-induced Reaction Cross Sections of {sup 181}Ta

    SciTech Connect

    Leeb, H. Schnabel, G.; Srdinko, Th.; Wildpaner, V.

    2015-01-15

    A new evaluation of neutron-induced reactions on {sup 181}Ta using a consistent procedure based on Bayesian statistics is presented. Starting point of the evaluation is the description of nuclear reactions via nuclear models implemented in TALYS 1.4. A retrieval of experimental data was performed and covariance matrices of the experiments were generated from an extensive study of the corresponding literature. All reaction channels required for a transport file up to 200 MeV have been considered and the covariance matrices of cross section uncertainties for the most important channels are determined. The evaluation has been performed in one step including all available experimental data. A comparison of the evaluated cross sections and spectra with experimental data and available evaluations is performed. In general the evaluated cross section reflect our best knowledge and give a fair description of the observables. However, there are few deviations from expectation which clearly indicate the impact of the prior and the need to account for model defects. Using the results of the evaluation a complete ENDF-file similarly to those of the TENDL library is generated.

  18. Experimental Study of the Cross Sections of {alpha}-Particle Induced Reactions on 209Bi

    SciTech Connect

    Hermanne, A.; Tarkanyi, F.; Takacs, S.; Szucs, Z.

    2005-05-24

    Alpha particle induced reactions for generation of 211At used in therapeutic nuclear medicine and possible contaminants were investigated with the stacked foil activation technique on natural bismuth targets up to E{alpha}=39 MeV. Excitation functions for the reactions 209Bi({alpha},2n)211At, 209Bi({alpha},3n)210At, 209Bi({alpha},x) 210Po obtained from direct alpha emission measurements and gamma spectra from decay products are compared with earlier literature values. Thick target yields have been deduced from the experimental cross sections.

  19. Empirical formula on (n,(3)He) reaction cross sections at 14.6MeV neutrons.

    PubMed

    Yiğit, Mustafa

    2015-11-01

    The systematic behavior of the cross sections of (n,(3)He) nuclear reactions has been studied by various researches at neutron energy of 14.6MeV. A new empirical formula based on the Q-value dependence of the cross sections of the investigated reaction has been proposed. The cross sections obtained from the new formula are compared with the other proposed formulae results and the experimental data. It seems that the present formula based on the Q-value dependence provides the good description for cross sections of neutron-induced (n,(3)He) nuclear reactions at 14.6MeV. PMID:26218596

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

    NASA Astrophysics Data System (ADS)

    Sargsyan, V. V.; Adamian, G. G.; Antonenko, N. V.; Diaz-Torres, A.; Gomes, P. R. S.; Lenske, H.

    2014-11-01

    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. A novel Coulomb scattering relation between angular momentum and centrifugal energy is used. The methodology is developed for addressing complementary reaction observables, improving the description of elastic differential cross section.

  1. Cross Sections Calculations of ( d, t) Nuclear Reactions up to 50 MeV

    NASA Astrophysics Data System (ADS)

    Tel, E.; Yiğit, M.; Tanır, G.

    2013-04-01

    In nuclear fusion reactions two light atomic nuclei fuse together to form a heavier nucleus. Fusion power is the power generated by nuclear fusion processes. In contrast with fission power, the fusion reaction processes does not produce radioactive nuclides. The fusion will not produce CO2 or SO2. So the fusion energy will not contribute to environmental problems such as particulate pollution and excessive CO2 in the atmosphere. Fusion powered electricity generation was initially believed to be readily achievable, as fission power had been. However, the extreme requirements for continuous reactions and plasma containment led to projections being extended by several decades. In 2010, more than 60 years after the first attempts, commercial power production is still believed to be unlikely before 2050. Although there have been significant research and development studies on the inertial and magnetic fusion reactor technology, there is still a long way to go to penetrate commercial fusion reactors to the energy market. In the fusion reactor, tritium self-sufficiency must be maintained for a commercial power plant. Therefore, for self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. Working out the systematics of ( d, t) nuclear reaction cross sections is of great importance for the definition of the excitation function character for the given reaction taking place on various nuclei at different energies. Since the experimental data of charged particle induced reactions are scarce, self-consistent calculation and analyses using nuclear theoretical models are very important. In this study, ( d, t) cross sections for target nuclei 19F, 50Cr, 54Fe, 58Ni, 75As, 89Y, 90Zr, 107Ag, 127I, 197Au and 238U have been investigated up to 50 MeV deuteron energy. The excitation functions for ( d, t) reactions have been calculated by pre-equilibrium reaction mechanism. Calculation results have been also compared with the available measurements in

  2. Hot fusion-evaporation cross sections of 45Sc -induced reactions with lanthanide targets

    NASA Astrophysics Data System (ADS)

    Werke, T. A.; Mayorov, D. A.; Alfonso, M. C.; Bennett, M. E.; DeVanzo, M. J.; Frey, M. M.; Tereshatov, E. E.; Folden, C. M.

    2015-09-01

    Background: 45Sc has rarely been studied as a projectile in fusion-evaporation reactions. The synthesis of new superheavy elements with Z >118 will require projectiles with Z >20 , and 45Sc could potentially be used for this purpose. Purpose: Cross sections were measured for the x n and p x n exit channels in the reactions of 45Sc with lanthanide targets for comparison to previous measurements of 48Ca reacting with similar targets. These data provide insight on the survival of spherical, shell-stabilized nuclei against fission, and could have implications for the discovery of new superheavy elements. Methods: Beams of 45Sc6 + were delivered from the K500 superconducting cyclotron at Texas A&M University with an energy of ≈5 MeV /nucleon . Products were purified using the Momentum Achromat Recoil Spectrometer, and excitation functions were measured for reactions of 45Sc+156-158,160Gd, 159Tb , and 162Dy at five or more energies each. Evaporation residues were identified by their characteristic α -decay energies. Experimental data were compared to a simple theoretical model to study each step in the fusion-evaporation process. Results: The maximum measured 4 n cross sections for the reactions 45Sc+156-158,160Gd, 159Tb , and 162Dy are 5.8 ±1.7 , 25 ±5 , 39 ±7 , 150 ±20 , 2 .4-1.4+2.3 , and 1.8 ±0.6 μ b , respectively. Proton emission competes effectively with neutron emission from the excited compound nucleus in most cases. The α ,α n , and α 2 n products were also observed in the 45Sc+162Dy reaction. Conclusions: Excitation functions were reported for 45Sc -induced reactions on lanthanide targets for the first time, and these cross sections are much smaller than for 48Ca -induced reactions on the same targets. The relative neutron-deficiency of the compound nuclei leads to significantly increased fissility and large reductions in the survival probability. Little evidence for improved production cross sections due to shell-stabilization was observed.

  3. Experimental determination of the {sup 26}Al(n,{alpha}){sup 23}Na reaction cross section and calculation of the Maxwellian averaged cross section at stellar temperatures

    SciTech Connect

    Smet, L. de; Wagemans, C.; Wagemans, J.; Heyse, J.; Gils, J. van

    2007-10-15

    The {sup 26}Al(n,{alpha}){sup 23}Na reaction cross section has been studied at the linear accelerator GELINA of the Institute for Reference Materials and Measurements in Geel, Belgium, and has been determined up to a neutron energy of about 100 keV using the time-of-flight technique. Six resonances could be observed in this energy region, whereas before only one had been identified experimentally. For four of them, resonance parameters such as resonance energy, total width, area, and spin of the state could be determined. From the obtained {sup 26}Al(n,{alpha}){sup 23}Na cross section data, Maxwellian averaged cross section (MACS) values were calculated by numerical integration. Since neutron induced reactions are among the major destruction mechanisms of {sup 26}Al in our Galaxy, these new MACS values contribute to a better understanding of the observed {sup 26}Al abundance.

  4. Direct measurement of the 22Ne(p,γ)23Na reaction cross section at LUNA

    NASA Astrophysics Data System (ADS)

    Ferraro, Federico; LUNA Collaboration

    2016-06-01

    The 22Ne(p, γ)23Na reaction takes part in the NeNa cycle of hydrogen burning, influencing the production of the elements between 20Ne and 27Al in red giant stars, asymptotic giant stars and classical novae. The 22Ne(p,γ)27Na reaction rate is very uncertain because of a large number of tentative resonances in the Gamow window, where only upper limits were quoted in literature. A direct measurement of the 22Ne(p, γ)23Na reaction cross section has been carried out at LUNA using a windowless differential-pumping gas target with two high- purity germanium (HPGe) detectors. A new measurement with a 4π bismuth germanate (BGO) summing detector is ongoing. During the HPGe phase of the experiment the strengths of the resonances at 156.2 keV, 189.5 keV and 259.7 keV have been directly measured for the first time and their contribution to the reaction rate has been calculated. The decay scheme of the newly discovered resonances has been established as well and some improved upper limits on the unobserved resonances have been put. The BGO detector with its 70% γ-detection efficiency allows to measure the cross section at lower energy. In order to further investigate the resonances at 71 keV and 105 keV and the direct-capture component, the data taking is ongoing.

  5. Angular distributions and cross-sections of projectile-like fragments in the 19F + 159Tb reaction

    NASA Astrophysics Data System (ADS)

    Kumar, Amit; Tripathi, R.; Sodaye, S.; Sudarshan, K.; Pujari, P. K.

    2013-01-01

    The angular distribution of projectile-like fragments (PLFs) in the 19F + 159Tb reaction have been measured at beam energy equal to 98MeV. Angular distributions of PLFs showed a systematic change with increasing mass transfer, starting from the peaking at grazing angle for heavier PLFs to very forward peaked angular distributions for lighter PLFs. Cross-sections of the different PLFs were obtained by integrating their centre-of-mass angular distributions. The PLF cross-sections have been compared with the incomplete fusion cross-sections obtained from the earlier measurement of the evaporation residue cross-section. Reduced cross-sections for lighter PLFs were observed to be higher compared to those observed in 19F + 66Zn reaction at similar values of E cm/ V b. Also, elastic scattering measurements were carried out to get information about the grazing angle and total reaction cross-section.

  6. Fission Cross Sections and Fission-Fragment Mass Yields via the Surrogate Reaction Method

    SciTech Connect

    Jurado, B.; Kessedjian, G.; Aiche, M.; Barreau, G.; Bidaud, A.; Czajkowski, S.; Dassie, D.; Haas, B.; Mathieu, L.; Osmanov, B.; Ahmad, I.

    2008-04-17

    The surrogate reaction method is a powerful tool to infer neutron-induced data of short-lived nuclei. After a short overview of the experimental techniques employed in the present surrogate experiments, we will concentrate on a recent measurement to determine neutron-induced fission cross sections for the actinides {sup 242,243}Cm and {sup 241}Am. The latest direct neutron-induced measurement for the {sup 243}Cm fission cross section is questioned by our results, since there are differences of more than 60% in the 0.7 to 7 MeV neutron energy range. Our experimental set-up has also enabled us to measure for the first time the fission fragment ''pseudo-mass'' distributions of {sup 243,244,245}Cm and {sup 242}Am compound nuclei in the excitation energy range from a few MeV to about 25 MeV.

  7. Activation cross sections for reactions induced by 14 MeV neutrons on natural tantalum

    SciTech Connect

    Luo Junhua; Tuo Fei; Kong Xiangzhong

    2009-05-15

    Cross sections for (n,2n), (n,p), (n,n{sup '}{alpha}), (n,t), (n,d{sup '}), and (n,{alpha}) reactions have been measured on tantalum isotopes at the neutron energies of 13.5 to 14.7 MeV using the activation technique. Data are reported for the following reactions: {sup 181}Ta(n,2n){sup 180}Ta{sup g}, {sup 181}Ta(n,p){sup 181}Hf, {sup 181}Ta(n,n{sup '}{alpha}){sup 177}Lu{sup m}, {sup 181}Ta(n,t){sup 179}Hf{sup m2}, {sup 181}Ta(n,d{sup '}){sup 180}Hf{sup m}, and {sup 181}Ta(n,{alpha}){sup 178}Lu{sup m}. The neutron fluences were determined using the monitor reaction {sup 27}Al(n,{alpha}){sup 24}Na. Results were discussed and compared with the previous works.

  8. Theoretical and experimental cross sections for neutron reactions on /sup 64/Zinc

    SciTech Connect

    Rutherford, D.A.

    1988-03-01

    Accurate measurements of the /sup 64/Zn (n,2n)/sup 63/Zn and /sup 64/Zn (n,p)/sup 64/Cu cross sections at 14.8 MeV have been made using a Texas Nuclear Neutron Generator and the activation technique. A NaI(Tl) spectrometer (using two 6'' x 6'' NaI detectors/crystals) was ued to measure the gamma radiation emitted in coincidence from the positron-emitting decay products. The measurements were made relative to /sup 65/Cu (n,2n)/sup 64/Cu and /sup 63/Cu (n,2n)/sup 62/Cu cross sections, which have similar half-lives, radiation emission, and were previously measured to high accuracy (2%). The value obtained for the (n,2n) measurement was 199 +- 6 millibarns, and a value of 176 +- 4.5 millibarns was obtained for the (n,p) measurement. In concert, a theoretical analysis of neutron induced reactions on /sup 64/Zn was performed at Los Alamos National Laboratory using the Hauser-Feshbach statistical theory in the GNASH code over an energy range of 100 keV to 20 MeV. Calculations included width fluctuation corrections, direct reaction contributions, and preequilibrium corrections above 6 MeV. Neutron optical model potentials were determined for zinc. The theoretical values agree with the new 14.8 MeV measurements approximately within experimental error, with calculations of 201 millibarns for the (n,2n) cross section and 170 millibarns for the (n,p) cross section. Results from the analysis will be made available in National Evaluated Nuclear Data Format (ENDF/B) for fusion energy applications. 50 refs., 34 figs., 10 tabs.

  9. Cross sections of proton- and neutron-induced reactions by the Liège intranuclear cascade model

    NASA Astrophysics Data System (ADS)

    Chen, Jian; Dong, Tiekuang; Ren, Zhongzhou

    2016-06-01

    The purpose of the paper is mainly to test the validity of the Liège intranuclear cascade (INCL) model in calculating the cross sections of proton-induced reactions for cosmogenic nuclei using the newly compiled database of proton cross sections. The model calculations of 3He display the rising tendency of cross sections with the increase of energy, in accordance with the experimental data. Meanwhile, the differences between the theoretical results and experimental data of production cross sections (10Be and 26Al) are generally within a factor of 3, meaning that the INCL model works quite well for the proton-induced reactions. Based on the good agreement, we predict the production cross sections of 26Al from reactions n + 27Al, n + 28Si, and n + 40Ca and those of 10Be from reactions n + 16O and n + 28Si. The results also show a good agreement with a posteriori excitation functions.

  10. Calculation of photo-nuclear reaction cross sections for 16O

    NASA Astrophysics Data System (ADS)

    Arasoglu, Ali; Faruk Ozdemir, Omer

    2015-07-01

    Because of the high thermal expansion coefficient of uranium, the fuel used in nuclear power plants is usually in the form of UO2 which has ceramic structure and small thermal expansion coefficient. UO2 include one uranium atom and two oxygen atoms. After fission progress, total energy values of emitted gamma are about 14 MeV. This gamma energy may cause transmutation of 16O isotopes. Transmutation of 16O isotopes changes physical properties of nuclear fuel. Due to above explanations, it is very important to calculate photo-nuclear reaction cross sections of 16O. In this study; for (γ,p), (γ,np), (γ,n) and (γ,2n) reactions of 16O, photo-nuclear reaction cross-sections were calculated using different models for pre-equilibrium and equilibrium effects. Taking incident gamma energy values up to 40 MeV, Hybrid and Cascade Exciton Models were used for pre-equilibrium calculations and Weisskopf-Ewing (Equilibrium) Model was used for equilibrium model calculations. Calculation results were compared with experimental and theoretical data. While experimental results were obtained from EXFOR, TENDL-2013, JENDL/PD-2004 and ENDF/B VII.1 data base were used to get theoretical results.

  11. Measurement of alpha-induced reaction cross sections on erbium isotopes for γ process studies

    NASA Astrophysics Data System (ADS)

    Kiss, G. G.; Szücs, T.; Török, Zs.; Fülöp, Zs.; Gyürky, Gy.; Halász, Z.; Somorjai, E.; Rauscher, T.

    2014-05-01

    The cross sections of the 162Er(α,γ)166Yb and 162,164,166Er(α,n)165,167,169Yb reactions have been measured at MTA Atomki. The radiative alpha capture reaction cross section was measured between Ec.m. = 11.21 MeV and Ec.m. = 16.09 MeV just above the astrophysically relevant energy region (which lies between 7.8 and 11.48 MeV at T9 = 3 GK). The 162Er(α,n)165Yb, 164Er(α,n)167Yb and 166Er(α,n)169Yb reactions were studied between Ec.m. = 12.19 and 16.09 MeV, Ec.m. = 13.17 and 16.59 MeV and Ec.m. = 12.68 and 17.08 MeV, respectively. The aim of this work is to provide experimental data for modeling the γ process which is thought to be responsible for the production of the proton-rich isotopes heavier than iron.

  12. Measurement of alpha-induced reaction cross sections on erbium isotopes for γ process studies

    SciTech Connect

    Kiss, G. G.; Szücs, T.; Török, Zs.; Fülöp, Zs.; Gyürky, Gy.; Halász, Z.; Somorjai, E.; Rauscher, T.

    2014-05-02

    The cross sections of the {sup 162}Er(α,γ){sup 166}Yb and {sup 162,164,166}Er(α,n){sup 165,167,169}Yb reactions have been measured at MTA Atomki. The radiative alpha capture reaction cross section was measured between E{sub c.m.} = 11.21 MeV and E{sub c.m.} = 16.09 MeV just above the astrophysically relevant energy region (which lies between 7.8 and 11.48 MeV at T{sub 9} = 3 GK). The {sup 162}Er(α,n){sup 165}Yb, {sup 164}Er(α,n){sup 167}Yb and {sup 166}Er(α,n){sup 169}Yb reactions were studied between E{sub c.m.} = 12.19 and 16.09 MeV, E{sub c.m.} = 13.17 and 16.59 MeV and E{sub c.m.} = 12.68 and 17.08 MeV, respectively. The aim of this work is to provide experimental data for modeling the γ process which is thought to be responsible for the production of the proton-rich isotopes heavier than iron.

  13. Experimental cross-sections for proton-induced nuclear reactions on natMo

    NASA Astrophysics Data System (ADS)

    Červenák, Jaroslav; Lebeda, Ondřej

    2016-08-01

    In the framework of the Co-ordinated Research Project of the IAEA, we measured in detail cross-sections of the nuclear reactions natMo(p,x)93gTc, 93mTc, 93m+gTc, 94gTc, 94mTc, 95gTc, 95mTc, 96m+gTc, 97mTc, 99mTc, 90Mo, 93mMo, 99Mo, 88gNb, 88mNb, 89gNb, 89mNb, 90m+gNb, 90m+gNbcum, 91mNb, 92mNb, 95gNb, 95mNb, 95m+gNb, 96Nb, 97m+gNb, 88m+gZrcum and 89m+gZrcum in the energy range of 6.9-35.8 MeV. The data for formation of 97mTc, 88gNb, 88mNb and 89mNb are reported for the first time. The obtained results were compared to the prediction of the nuclear reaction model code TALYS adopted from the TENDL-2015 library and to the previously published cross-sections. The thick target yields for all the radionuclides were calculated from the measured data. We suggest recommended cross-sections and thick target yields for the 100Mo(p,2n)99mTc, 100Mo(p,x)99Mo and natMo(p,x)96m+gTc nuclear reactions deduced from the selected experimental data.

  14. Differential cross sections and spin density matrix elements for the reaction gamma p -> p omega

    SciTech Connect

    M. Williams, D. Applegate, M. Bellis, C.A. Meyer

    2009-12-01

    High-statistics differential cross sections and spin density matrix elements for the reaction gamma p -> p omega have been measured using the CLAS at Jefferson Lab for center-of-mass (CM) energies from threshold up to 2.84 GeV. Results are reported in 112 10-MeV wide CM energy bins, each subdivided into cos(theta_CM) bins of width 0.1. These are the most precise and extensive omega photoproduction measurements to date. A number of prominent structures are clearly present in the data. Many of these have not previously been observed due to limited statistics in earlier measurements.

  15. Investigation of activation cross-sections of alpha-induced nuclear reactions on natural cadmium

    NASA Astrophysics Data System (ADS)

    Khandaker, Mayeen Uddin; Kim, Kwangsoo; Lee, Manwoo; Kim, Guinyun

    2014-08-01

    We measured production cross-sections of Sn, In, and Cd radionuclides from alpha-induced reactions on natCd from their respective threshold to 45 MeV by using a stacked-foil activation technique at the MC-50 cyclotron of the Korea Institute of Radiological and Medical Sciences. The results were compared with the earlier measurements as well as with the theoretical values obtained from the TENDL-2012 library based on the TALYS 1.4 code. Our measurements for the 110,113g,117mSn, 108m,108g,109g,110m,110g,111g,113m,114m,115m,116m,117m,117gIn, and 111m,115gCd radionuclides in the energy region from the threshold energy to 45 MeV are in general good agreement with the other experimental data and calculated results. The integral yields for thick target were also deduced using the measured cross-sections and the stopping power of natural cadmium target and found in agreement with the directly measured yields available in the literature. The measured cross-sections find importance in various practical applications including nuclear medicine and improvement of nuclear model calculations.

  16. Alpha capture reaction cross section measurements on Sb isotopes by activation method

    NASA Astrophysics Data System (ADS)

    Korkulu, Z.; Özkan, N.; Kiss, G. G.; Szücs, T.; Fülöp, Zs; Güray, R. T.; Gyürky, Gy; Halász, Z.; Somorjai, E.; Török, Zs; Yalçin, C.

    2016-01-01

    Alpha induced reactions on natural and enriched antimony targets were investigated via the activation technique in the energy range from 9.74 MeV to 15.48 MeV, close to the upper end of the Gamow window at a temperature of 3 GK relevant to the γ-process. The experiments were carried out at the Institute for Nuclear Research, the Hungarian Academy of Sciences (MTA Atomki). 121Sb(α,γ)125I, 121Sb(α,n)124I and 123Sb(α,n)126I reactions were measured using a HPGe detector. In this work, the 121Sb(α,n)124 cross section results and the comparison with the theoretical predictions (obtained with standard settings of the statistical model codes NON-SMOKER and TALYS) were presented.

  17. 232Th(n,{gamma})233Th Thermal Reaction Cross-Section Measurement

    SciTech Connect

    Maidana, Nora L.; Vanin, Vito R.; Pascholati, Paulo R.; Helene, Otaviano; Castro, Ruy M.; Dias, Mauro S.; Koskinas, Marina F.

    2005-05-24

    The 232Th(n,{gamma})233Th thermal neutron-capture reaction cross section was measured using targets of {approx} 1.5 mg of high-purity metallic thorium irradiated in the IPEN IEA-R1m 5 MW pool research reactor. The 197Au(n,{gamma})198Au reaction was used to monitor the thermal and epithermal neutron fluxes in the irradiation position, which was found using the Westcott formalism. The residual gamma-ray activity was followed with an HPGe detector. The detector efficiency curve was fitted by the least-squares method applying covariance analysis to all uncertainties involved. The experimental result is {sigma}0 =7.20{+-}0.20 b, in agreement with previous published values.

  18. Experience in using the covariances of some ENDF/B-V dosimetry cross sections: proposed improvements and addition of cross-reaction covariances

    SciTech Connect

    Fu, C.Y.; Hetrick, D.M.

    1982-01-01

    Recent ratio data, with carefully evaluated covariances, were combined with eleven of the ENDF/B-V dosimetry cross sections using the generalized least-squares method. The purpose was to improve these evaluated cross sections and covariances, as well as to generate values for the cross-reaction covariances. The results represent improved cross sections as well as realistic and usable covariances. The latter are necessary for meaningful intergral-differential comparisons and for spectrum unfolding.

  19. Elastic Scattering and Reaction Cross Section of the 6He+27Al System Close to the Coulomb Barrier

    NASA Astrophysics Data System (ADS)

    Lépine-Szily, A.; Benjamim, E. A.; Lichtenthäler, R.; Guimarães, V.; Gomes, P. R. S.; Chamon, L. C.; Hussein, M. S.; Arazi, A.; Padron, I.; Alcantara Nuñez, J.; Assunção, M.; Barioni, A.; Camargo, O.; Denke, R. Z.; de Faria, P. N.; Mendes Junior, D. R.; Pires, K. C. C.

    2006-08-01

    The RIBRAS (Radioactive Ion Beams Brazil) facility recently installed at the Pelletron Laboratory of the University of São Paulo consists of two superconducting solenoids used to produce and focalize beams of light radioactive nuclei, as 6He, 7Be,8Li etc. The low energy, light, radioactive beams available are used to study reactions close to the Coulomb barrier. The elastic scattering of the radioactive halo nucleus 6He on 27Al target was measured at four energies close to the Coulomb barrier. Reaction cross sections were extracted from the optical model fits, using the São Paulo Potential (SPP). The reduced reaction cross sections of 6He on 27Al were compared to reduced reaction cross sections for other projectiles as 6,7Li, 9Be and 16O on 27Al and they are larger than those for stable projectiles by an amount similar to the calculated nuclear break-up cross section for this system.

  20. Study for Nuclear Structures of 22-35Na Isotopes via Measurements of Reaction Cross Sections

    NASA Astrophysics Data System (ADS)

    Suzuki, Shinji

    2014-09-01

    T. Ohtsubo, M. Nagashima, T. Ogura, Y. Shimbara (Grad. Sch. of Sc., Niigata Univ.), M.Takechi, H. Geissel, M. Winkler (GSI), D. Nishimura, T. Sumikama (Dept. of Phys., Tokyo Univ. of Sc.), M. Fukuda, M. Mihara, H. Uenishi (Dept. of Phys., Osaka Univ.), T. Kuboki, T. Suzuki, T. Yamaguchi, H. Furuki, C. S. Lee, K. Sato (Dept. of Phys., Saitama Univ.), A. Ozawa, H. Ohnishi, T. Moriguchi, S. Fukuda, Y. Ishibashi, D. Nagae, R. Nishikiori, T. Niwa (Inst. of Phys., Univ. of Tsukuba), N. Aoi (RCNP), Rui-Jiu Chen, N. Inabe, D. Kameda, T. Kubo, M. Lantz, T. Ohnishi, K. Okumura, H. Sakurai, H. Suzuki, H. Takeda, S. Takeuchi, K. Tanaka, Y. Yanagisawa (RIKEN), De-Qing Fang, Yu-Gang Ma (SINAP), T. Izumikawa (RI Ctr., Niigata Univ.), and S. Momota (Fac. of Engn., Kochi Univ. of Tech.) Reaction cross sections (σR) for 22-35Na isotopes have been measured at around 240 MeV/nucleon. The σR for 22-35Na were measured for the first time. Enhancement in cross sections is clearly observed from the systematics for stable nuclei, for isotopes with large mass numbers. These enhancement can be mainly ascribed to the nuclear deformation. We will discuss the nuclear structure (neutron skin, nuclear shell structure) for neutron-excess Na isotopes. T. Ohtsubo, M. Nagashima, T. Ogura, Y. Shimbara (Grad. Sch. of Sc., Niigata Univ.), M.Takechi, H. Geissel, M. Winkler (GSI), D. Nishimura, T. Sumikama (Dept. of Phys., Tokyo Univ. of Sc.), M. Fukuda, M. Mihara, H. Uenishi (Dept. of Phys., Osaka Univ.), T. Kuboki, T. Suzuki, T. Yamaguchi, H. Furuki, C. S. Lee, K. Sato (Dept. of Phys., Saitama Univ.), A. Ozawa, H. Ohnishi, T. Moriguchi, S. Fukuda, Y. Ishibashi, D. Nagae, R. Nishikiori, T. Niwa (Inst. of Phys., Univ. of Tsukuba), N. Aoi (RCNP), Rui-Jiu Chen, N. Inabe, D. Kameda, T. Kubo, M. Lantz, T. Ohnishi, K. Okumura, H. Sakurai, H. Suzuki, H. Takeda, S. Takeuchi, K. Tanaka, Y. Yanagisawa (RIKEN), De-Qing Fang, Yu-Gang Ma (SINAP), T. Izumikawa (RI Ctr., Niigata Univ.), and S. Momota (Fac. of Engn

  1. Determination of the ^6He Nuclear Radius from the Total Reaction Cross Section of ^6He + ^9Be

    NASA Astrophysics Data System (ADS)

    Pires, K. C. C.; Appannababu, S.; Lichtenthäler, R.

    2016-05-01

    A new method to obtain the nuclear radius from low energies total reaction cross section measurements is presented. Elastic scattering angular distributions of ^6He on ^9Be at two energies, namely, E_{cm}= 9.72 and 12.78 MeV, were analysed previously and the total reaction cross sections obtained are used to assess the ^6He nuclear interaction radius. A comparison with the radius of the ^6He obtained at higher energies is presented.

  2. Extracting nuclear sizes of medium to heavy nuclei from total reaction cross sections

    NASA Astrophysics Data System (ADS)

    Horiuchi, W.; Hatakeyama, S.; Ebata, S.; Suzuki, Y.

    2016-04-01

    Background: Proton and neutron radii are fundamental quantities of atomic nuclei. To study the sizes of short-lived unstable nuclei, there is a need for an alternative to electron scattering. Purpose: The recent paper by Horiuchi et al. [Phys. Rev. C 89, 011601(R) (2014)], 10.1103/PhysRevC.89.011601 proposed a possible way of extracting the matter and neutron-skin thickness of light- to medium-mass nuclei using total reaction cross section, σR. The analysis is extended to medium to heavy nuclei up to lead isotopes with due attention to Coulomb breakup contributions as well as density distributions improved by paring correlation. Methods: We formulate a quantitative calculation of σR based on the Glauber model including the Coulomb breakup. To substantiate the treatment of the Coulomb breakup, we also evaluate the Coulomb breakup cross section due to the electric dipole field in a canonical-basis-time-dependent-Hartree-Fock-Bogoliubov theory in the three-dimensional coordinate space. Results: We analyze σR's of 103 nuclei with Z =20 , 28, 40, 50, 70, and 82 incident on light targets, H,21, 4He, and 12C. Three kinds of Skyrme interactions are tested to generate those wave functions. To discuss possible uncertainty due to the Coulomb breakup, we examine its dependence on the target, the incident energy, and the Skyrme interaction. The proton is a most promising target for extracting the nuclear sizes as the Coulomb excitation can safely be neglected. We find that the so-called reaction radius, aR=√{σR/π } , for the proton target is very well approximated by a linear function of two variables, the matter radius and the skin thickness, in which three constants depend only on the incident energy. We quantify the accuracy of σR measurements needed to extract the nuclear sizes. Conclusions: The proton is the best target because, once the incident energy is set, its aR is very accurately determined by only the matter radius and neutron-skin thickness. If σR's at

  3. Capture Cross Sections for the Near Symmetric 124Sn + 96Zr Reaction

    SciTech Connect

    Vinodkumar, A. M.; Loveland, Walter; Sprunger, Peter H; Peterson, Don; Liang, Junjien; Shapira, Dan; Varner Jr, Robert L; Gross, Carl J; Kolata, Jim J

    2006-12-01

    Capture-fission cross sections were measured for the near symmetric reaction between the massive nuclei {sup 124}Sn and {sup 96}Zr for center of mass energies from 195 to 265 MeV. Coincident fission fragments were detected and separated from elastic and deep inelastic scattering products by angle/energy/mass conditions. The measured capture cross sections agree quite well with calculations using the dinuclear system (DNS) model. The DNS model also predicts the fusion cross section for this reaction with a fusion barrier height of 208.0 MeV. The deduced extra push energy, corresponding to this barrier height, differs from that deduced from evaporation residue measurements.

  4. Capture Cross Sections for the Near Symmetric 124Sn+96Zr Reaction

    SciTech Connect

    Vinodkumar, A. M.; Loveland, Walter; Sprunger, Peter H; Peterson, Don; Liang, J Felix; Shapira, Dan; Varner Jr, Robert L; Gross, Carl J; Kolata, Jim J

    2006-12-01

    Capture-fission cross sections were measured for the near symmetric reaction between the massive nuclei 124Sn and 96Zr for center of mass energies from 195 to 265 MeV. Coincident fission fragments were detected and separated from elastic and deep inelastic scattering products by angle/energy/mass conditions. The measured capture cross sections agree quite well with calculations using the dinuclear system (DNS) model. The DNS model also predicts the fusion cross section for this reaction with a fusion barrier height of 208.0 MeV. The deduced extra push energy, corresponding to this barrier height, differs from that deduced from evaporation residue measurements.

  5. Differential cross sections and recoil polarizations for the reaction γp→K+Σ0

    NASA Astrophysics Data System (ADS)

    Dey, B.; Meyer, C. A.; Bellis, M.; McCracken, M. E.; Williams, M.; Adhikari, K. P.; Aghasyan, M.; Anghinolfi, M.; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Berman, B. L.; Biselli, A. S.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Carman, D. S.; Crede, V.; D'Angelo, A.; Daniel, A.; de Vita, R.; de Sanctis, E.; Deur, A.; Dhamija, S.; Dickson, R.; Djalali, C.; Doughty, D.; Dugger, M.; Dupre, R.; El Alaoui, A.; El Fassi, L.; Eugenio, P.; Fegan, S.; Fradi, A.; Gabrielyan, M. Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gohn, W.; Gothe, R. W.; Graham, L.; Griffioen, K. A.; Guler, N.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Hassall, N.; Hicks, K.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Jawalkar, S. S.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Khetarpal, P.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Konczykowski, P.; Kubarovsky, V.; Kuleshov, S. V.; Kuznetsov, V.; Livingston, K.; MacGregor, I. J. D.; Martinez, D.; McAndrew, J.; McKinnon, B.; Mikhailov, K.; Mirazita, M.; Mokeev, V.; Moreno, B.; Moriya, K.; Morrison, B.; Moutarde, H.; Munevar, E.; Nadel-Turonski, P.; Nasseripour, R.; Nepali, C. S.; Ni, A.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niroula, M. R.; Osipenko, M.; Ostrovidov, A. I.; Paremuzyan, R.; Park, K.; Park, S.; Pasyuk, E.; Pereira, S. Anefalos; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Raue, B. A.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Salamanca, J.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Seraydaryan, H.; Sharabian, Y. G.; Smith, E. S.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Strakovsky, I. I.; Strauch, S.; Tang, W.; Taylor, C. E.; Tedeschi, D. J.; Tkachenko, S.; Ungaro, M.; Watts, D. P.; Vernarsky, B.; Vineyard, M. F.; Voutier, E.; Weinstein, L. B.; Wood, M. H.; Yegneswaran, A.; Zhang, J.; Zhao, B.; Zhao, Z. W.

    2010-08-01

    High-statistics measurements of differential cross sections and recoil polarizations for the reaction γp→K+Σ0 have been obtained using the CLAS detector at Jefferson Lab. We cover center-of-mass energies (s) from 1.69 to 2.84 GeV, with an extensive coverage in the K+ production angle. Independent measurements were made using the K+pπ-(γ) and K+p(π-,γ) final-state topologies, and were found to exhibit good agreement. Our differential cross sections show good agreement with earlier CLAS, SAPHIR, and LEPS results, while offering better statistical precision and a 300-MeV increase in s coverage. Above s≈2.5 GeV, t- and u-channel Regge scaling behavior can be seen at forward and backward angles, respectively. Our recoil polarization (PΣ) measurements represent a substantial increase in kinematic coverage and enhanced precision over previous world data. At forward angles, we find that PΣ is of the same order of magnitude but opposite sign as PΛ, in agreement with the static SU(6) quark model prediction of PΣ≈-PΛ. This expectation is violated in some mid- and backward-angle kinematic regimes, where PΣ and PΛ are of similar magnitudes but also have the same signs. In conjunction with several other meson photoproduction results recently published by CLAS, the present data will help constrain the partial-wave analyses being performed to search for missing baryon resonances.

  6. Measurement of (α,n) reaction cross sections of erbium isotopes for testing astrophysical rate predictions

    NASA Astrophysics Data System (ADS)

    Kiss, G. G.; Szücs, T.; Rauscher, T.; Török, Zs; Csedreki, L.; Fülöp, Zs; Gyürky, Gy; Halász, Z.

    2015-05-01

    The γ-process in core-collapse and/or type Ia supernova explosions is thought to explain the origin of the majority of the so-called p nuclei (the 35 proton-rich isotopes between Se and Hg). Reaction rates for γ-process reaction network studies have to be predicted using Hauser-Feshbach statistical model calculations. Recent investigations have shown problems in the prediction of α-widths at astrophysical energies which are an essential input for the statistical model. It has an impact on the reliability of abundance predictions in the upper mass range of the p nuclei. With the measurement of the 164,166Er(α,n)167,169Yb reaction cross sections at energies close to the astrophysically relevant energy range we tested the recently suggested low energy modification of the α+nucleus optical potential in a mass region where γ-process calculations exhibit an underproduction of the p nuclei. Using the same optical potential for the α-width which was derived from combined 162Er(α,n) and 162Er(α,γ) measurement makes it plausible that a low-energy modification of the optical α+nucleus potential is needed.

  7. Partial Cross-Sections of ^140Ce(n,2n)^139Ce Reaction

    NASA Astrophysics Data System (ADS)

    Angell, C. T.; Fallin, B.; Hutcheson, A.; Karwowski, H. J.; Kelley, J. H.; Tonchev, A. P.; Tornow, W.

    2006-10-01

    The excitation function for the ^140Ce(n,2n)^139Ce reaction has been studied in the TUNL Shielded Neutron Source area. A pulsed and quasi-monoenergetic neutron beam was produced via the D(d,n) reaction (δE/E=3-5%) with energies of 12, 13.3, 14.5, and 16 MeV with a beam flux of ˜10^4 n/(s*cm)^2. The target consisted of a mixture of natural Ce and Fe. Two clover and two planar HPGe detectors were used to make in-beam measurements of the γ-ray cascade deexciting ^139Ce. The partial cross sections were normalized to the 847 keV transition in ^56Fe. Statistical model calculations using code EMPIRE will be compared with the present data as well as with the previously obtained [1] transition amplitudes for the ^140Ce(γ,n)^139Ce reaction. [1] C.T.Angell et al. CGS 12. Notre Dame, IN, 2005, p. 363.

  8. Cross Sections for Neutron-induced Reactions on Actinide Targets Extracted from Surrogate Experiments: A Status Report

    SciTech Connect

    Escher, J E; Burke, J T; Dietrich, F S; Lesher, S R; Scielzo, N D; Thompson, I J; Younes, W

    2009-10-01

    The Surrogate nuclear reactions method, an indirect approach for determining cross sections for compound-nuclear reactions involving difficult-to-measure targets, is reviewed. Focusing on cross sections for neutron-induced reactions on actinides, we review the successes of past and present applications of the method and assess its uncertainties and limitations. The approximations used in the analyses of most experiments work reasonably well for (n,f) cross sections for neutron energies above 1-2 MeV, but lead to discrepancies for low-energy (n,f) reactions, as well as for (n,{gamma}) applications. Correcting for some of the effects neglected in the approximate analyses leads to improved (n,f) results. We outline steps that will further improve the accuracy and reliability of the Surrogate method and extend its applicability to reactions that cannot be approached with the present implementation of the method.

  9. Reaction cross-section calculations using new experimental and theoretical level structure data for deformed nuclei

    SciTech Connect

    Hoff, R.W.; Gardner, D.G.; Gardner, M.A.

    1984-10-05

    A technique for modeling quasiparticle excitation energies and rotational parameters in odd-odd deformed nuclei has been used to construct sets of discrete states with energy 0 to 1.5 MeV in /sup 176/Lu and /sup 236/Np. These data were used as part of the input for calculation of isomer production cross-section ratios in the /sup 175/Lu(n,..gamma..)/sup 176/Lu and /sup 237/Np(n,2n)/sup 236/Np reactions. In order to achieve agreement with experiment, it has been found necessary to include in the modeled set many rotational bands (35 to 95), which are comprised of hundreds of levels with their gamma-ray branching ratios. It is essential that enough bands be included to produce a representative selection of K quantum numbers in the de-excitation cascade. 20 refs., 3 figs., 3 tabs.

  10. Differential cross sections and spin density matrix elements for the reaction γp→pω

    NASA Astrophysics Data System (ADS)

    Williams, M.; Applegate, D.; Bellis, M.; Meyer, C. A.; Adhikari, K. P.; Anghinolfi, M.; Baghdasaryan, H.; Ball, J.; Battaglieri, M.; Bedlinskiy, I.; Berman, B. L.; Biselli, A. S.; Bookwalter, C.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Careccia, S. L.; Carman, D. S.; Cole, P. L.; Collins, P.; Crede, V.; D'Angelo, A.; Daniel, A.; Vita, R. De; Sanctis, E. De; Deur, A.; Dey, B.; Dhamija, S.; Dickson, R.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dugger, M.; Dupre, R.; Alaoui, A. El; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Fradi, A.; Gabrielyan, M. Y.; Garçon, M.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Hassall, N.; Hicks, K.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jawalkar, S. S.; Jo, H. S.; Johnstone, J. R.; Joo, K.; Keller, D.; Khandaker, M.; Khetarpal, P.; Kim, W.; Klein, A.; Klein, F. J.; Krahn, Z.; Kubarovsky, V.; Kuleshov, S. V.; Kuznetsov, V.; Livingston, K.; Lu, H. Y.; Mayer, M.; McAndrew, J.; McCracken, M. E.; McKinnon, B.; Mikhailov, K.; Mirazita, M.; Mokeev, V.; Moreno, B.; Moriya, K.; Morrison, B.; Moutarde, H.; Munevar, E.; Nadel-Turonski, P.; Nepali, C. S.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niroula, M. R.; Niyazov, R. A.; Osipenko, M.; Ostrovidov, A. I.; Paris, M.; Park, K.; Park, S.; Pasyuk, E.; Pereira, S. Anefalos; Perrin, Y.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Raue, B. A.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salamanca, J.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seraydaryan, H.; Sharabian, Y. G.; Smith, E. S.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tedeschi, D. J.; Tkachenko, S.; Ungaro, M.; Vineyard, M. F.; Voutier, E.; Watts, D. P.; Weinstein, L. B.; Weygand, D. P.; Wood, M. H.; Zhang, J.; Zhao, B.

    2009-12-01

    High-statistics differential cross sections and spin-density matrix elements for the reaction γp→pω have been measured using the CEBAF large acceptance spectrometer (CLAS) at Jefferson Lab for center-of-mass (c.m.) energies from threshold up to 2.84 GeV. Results are reported in 11210-MeV wide c.m. energy bins, each subdivided into cosθc.m.ω bins of width 0.1. These are the most precise and extensive ω photoproduction measurements to date. A number of prominent structures are clearly present in the data. Many of these have not previously been observed due to limited statistics in earlier measurements.

  11. Activation cross sections of proton induced nuclear reactions on gold up to 65MeV.

    PubMed

    Ditrói, F; Tárkányi, F; Takács, S; Hermanne, A

    2016-07-01

    Activation cross sections of proton induced reactions on gold for production of (197m,197g,195m,195g, 193m,193g,192)Hg, (196m,196g(cum),195g(cum),194,191(cum))Au, (191(cum))Pt and (192)Ir were measured up to 65MeV proton energy, some of them for the first time. The new data are in acceptably good agreement with the recently published earlier experimental data in the overlapping energy region. The experimental data are compared with the predictions of the TALYS 1.6 (results in TENDL-2015 on-line library) and EMPIRE 3.2 code. PMID:27156194

  12. Vibrational state-resolved differential cross sections for the D + H sub 2 yields DH + H reaction

    SciTech Connect

    Continetti, R.E.

    1989-11-01

    In this thesis, crossed-molecular-beams studies of the reaction D + H{sub 2} {yields} DH + H at collision energies of 0.53 and 1.01 eV are reported. Chapter 1 provides a survey of important experimental and theoretical studies on the dynamics of the hydrogen exchange reaction. Chapter 2 discusses the development of the excimer-laser photolysis D atom beam source that was used in these studies and preliminary experiments on the D + H{sub 2} reaction. In Chapter 3, the differential cross section measurements are presented and compared to recent theoretical predictions. The measured differential cross sections for rotationally excited DH products showed significant deviations from recent quantum scattering calculations, in the first detailed comparison of experimental and theoretical differential cross sections. These results indicate that further work on the H{sub 3} potential energy surface, particularly the bending potential, is in order.

  13. Cross Section Measurements of the 76Ge (n ,n' γ) Reaction

    NASA Astrophysics Data System (ADS)

    Crider, B. P.; Peters, E. E.; Prados-Estévez, F. M.; Ross, T. J.; McEllistrem, M. T.; Yates, S. W.; Vanhoy, J. R.

    2013-10-01

    Neutrinoless double-beta decay (0 νββ) is a topic of great current interest and, as such, is the focus of several experiments and international collaborations. Two of these experiments, Majorana and GERDA, are seeking evidence of 0 νββ in the decay of 76Ge, where the signal would appear as a sharp peak in the energy spectrum at the Q-value of the reaction plus a small amount of recoil energy, or 2039 keV. Due to the high sensitivity of such a measurement, knowledge of background lines is critical. A study of 76Ga β- decay into 76Ge revealed a 2040.70(25)-keV transition from the 3951.70(14)-keV level, which, if populated, could potentially be a background line of concern. In addition to β- decay from 76Ga, a potential population mechanism could be cosmic-ray-induced inelastic neutron scattering. Measurements of the neutron-induced cross section of the 3951.70-keV level have been performed utilizing the 76 Ge (n ,n' γ) reaction at the University of Kentucky at neutron energies ranging from 4.3 to 4.9 MeV. This material is based upon work is supported by the U.S. National Science Foundation under grant no. PHY-0956310.

  14. New data on cross sections for partial and total photoneutron reactions on the isotopes {sup 91,94}Zr

    SciTech Connect

    Varlamov, V. V.; Makarov, M. A.; Peskov, N. N.; Stepanov, M. E.

    2015-07-15

    Experimental data on {sup 91,94}Zr photodisintegration that were obtained in a beam of quasimonoenergetic annihilation photons by the method of neutron multiplicity sorting are analyzed. It is found that the cross sections for the (γ, 1n), (γ, 2n), and (γ, 3n) reactions on both isotopes do not meet the objective data-reliability criteria formulated earlier. Within the experimental–theoretical method for evaluating partial-reaction cross sections that satisfy these criteria, new data on the cross sections for the aforementioned partial reactions, as well as for the (γ, sn) = (γ, 1n) + (γ, 2n) + (γ, 3n) +... total photoneutron reaction, are obtained for the isotopes {sup 91,94}Zr.

  15. New data on cross sections for partial and total photoneutron reactions on the isotopes 91,94Zr

    NASA Astrophysics Data System (ADS)

    Varlamov, V. V.; Makarov, M. A.; Peskov, N. N.; Stepanov, M. E.

    2015-07-01

    Experimental data on 91,94Zr photodisintegration that were obtained in a beam of quasimonoenergetic annihilation photons by the method of neutron multiplicity sorting are analyzed. It is found that the cross sections for the ( γ, 1 n), ( γ, 2 n), and ( γ, 3 n) reactions on both isotopes do not meet the objective data-reliability criteria formulated earlier. Within the experimental-theoretical method for evaluating partial-reaction cross sections that satisfy these criteria, new data on the cross sections for the aforementioned partial reactions, as well as for the ( γ, sn) = ( γ, 1 n) + ( γ, 2 n) + ( γ, 3 n) +... total photoneutron reaction, are obtained for the isotopes 91,94Zr.

  16. Revised Production Rates for Na-22 and Mn-54 in Meteorites Using Cross Sections Measured for Neutron-induced Reactions

    NASA Technical Reports Server (NTRS)

    Sisterson, J. M.; Kim, K. J.; Reedy, R. C.

    2004-01-01

    The interactions of galactic cosmic rays (GCR) with extraterrestrial bodies produce small amounts of radionuclides and stable isotopes. The production rates of many relatively short-lived radionuclides, including 2.6-year Na-22 and 312-day Mn-54, have been measured in several meteorites collected very soon after they fell. Theoretical models used to calculate production rates for comparison with the measured values rely on input data containing good cross section measurements for all relevant reactions. Most GCR particles are protons, but secondary neutrons make most cosmogenic nuclides. Calculated production rates using only cross sections for proton-induced reactions do not agree well with measurements. One possible explanation is that the contribution to the production rate from reactions initiated by secondary neutrons produced in primary GCR interactions should be included explicitly. This, however, is difficult to do because so few of the relevant cross sections for neutron-induced reactions have been measured.

  17. Experimental Cross Sections for Reactions of Heavy Ions and 208Pb, 209Bi, 238U, and 248Cm Targets

    SciTech Connect

    Patin, Joshua B.

    2002-05-24

    The study of the reactions between heavy ions and {sup 208}Pb, {sup 209}Bi, {sup 238}U, and {sup 248} Cm targets was performed to look at the differences between the cross sections of hot and cold fusion reactions. Experimental cross sections were compared with predictions from statistical computer codes to evaluate the effectiveness of the computer code in predicting production cross sections. Hot fusion reactions were studied with the MG system, catcher foil techniques and the Berkeley Gas-filled Separator (BGS). 3n- and 4n-exit channel production cross sections were obtained for the {sup 238}U({sup 18}O,xn){sup 256-x}Fm, {sup 238}U({sup 22}Ne,xn){sup 260-x}No, and {sup 248}Cm({sup 15}N,xn){sup 263-x}Lr reactions and are similar to previous experimental results. The experimental cross sections were accurately modeled by the predictions of the HIVAP code using the Reisdorf and Schaedel parameters and are consistent with the existing systematics of 4n exit channel reaction products. Cold fusion reactions were examined using the BGS. The {sup 208}Pb({sup 48}Ca,xn){sup 256-x}No, {sup 208}Pb({sup 50}Ti,xn){sup 258-x}Rf, {sup 208}Pb({sup 51}V,xn){sup 259-x}Db, {sup 209}Bi({sup 50}Ti,xn){sup 259-x}Db, and {sup 209}Bi({sup 51}V,xn){sup 260-x}Sg reactions were studied. The experimental production cross sections are in agreement with the results observed in previous experiments. It was necessary to slightly alter the Reisdorf and Schaedel parameters for use in the HIVAP code in order to more accurately model the experimental data. The cold fusion experimental results are in agreement with current 1n- and 2n-exit channel systematics.

  18. Validation of Cross Sections with Criticality Experiment and Reaction Rates: the Neptunium Case

    NASA Astrophysics Data System (ADS)

    Leong, L. S.; Tassan-Got, L.; Audouin, L.; Berthier, B.; Le Naour, C.; Stéphan, C.; Paradela, C.; Tarrío, D.; Duran, I.

    2014-04-01

    The 237Np neutron-induced fission cross section has been recently measured in a large energy range (from eV to GeV) at the n_TOF facility at CERN. When compared to previous measurements the n_TOF fission cross section appears to be higher by 5-7% beyond the fission threshold. To check the relevance of the n_TOF data, we considered a criticality experiment performed at Los Alamos with a 6 kg sphere of 237Np, surrounded by uranium highly enriched in 235U so as to approach criticality with fast neutrons. The multiplication factor keff of the calculation is in better agreement with the experiment when we replace the ENDF/B-VII.0 evaluation of the 237Np fission cross section by the n_TOF data. We also explored the hypothesis of deficiencies of the inelastic cross section in 235U which has been invoked by some authors to explain the deviation of 750 pcm. The large modification needed to reduce the deviation seems to be incompatible with existing inelastic cross section measurements. Also we show that the νbar of 237Np can hardly be incriminated because of the high accuracy of the existing data. Fission rate ratios or averaged fission cross sections measured in several fast neutron fields seem to give contradictory results on the validation of the 237Np cross section but at least one of the benchmark experiments, where the active deposits have been well calibrated for the number of atoms, favors the n_TOF data set. These outcomes support the hypothesis of a higher fission cross section of 237Np.

  19. Quantum state-to-state cross sections for atom-diatom reactions: A Chebyshev real wave-packet approach

    SciTech Connect

    Lin Shiying; Guo Hua

    2006-08-15

    We describe the implementation of a quantum mechanical method to calculate state-to-state differential cross sections for atom-diatom reactive scattering processes. The key ingredient of this approach is the efficient and accurate propagation of a real scattering wave packet in the Chebyshev order domain, from which the S-matrix elements can be extracted. This approach is implemented with Open MP and applied to compute differential and integral cross sections for the direct H+H{sub 2} abstraction reaction and the more challenging N({sup 2}D)+H{sub 2} insertion reaction.

  20. Sensitivity of Activation Cross Sections of Tungsten to Nuclear Reaction Mechanisms

    SciTech Connect

    Avrigeanu, V.; Forrest, R.A.; Koning, A.J.

    2005-05-24

    In order to reduce the deviation of calculated-to-experimental activity (C/E) following benchmark experiments with pure W irradiated by 14-MeV neutrons, of interest for safety aspects and waste management of power plants, a detailed analysis of the activation cross sections was carried out using the computer codes EMPIRE-II and TALYS as well as local parameter sets within the STAPRE-H code. The sensitivity of the calculated cross sections to various model parameters is derived and discussed in connection with improving the C/E of the benchmark experiment.

  1. (65)Cu isomeric cross sections for (n,α) reaction using approximately 14MeV neutrons.

    PubMed

    Durusoy, Ayşe; Reyhancan, Iskender Atilla; Akçalı, Özgür

    2015-05-01

    In this paper, activation cross-section measurements for the (65)Cu(n,α)(62m)Co (T1/2=13.86min.) reaction at six different neutron energies ranging from 13.6 and 14.9MeV are presented. The fast neutrons were produced via (3)H(d, n)(4)He reactions from an SAMES T-400 neutron generator. An activation technique was used to measure induced gamma activities. A high-resolution gamma-ray spectrometer with a high-purity germanium (HpGe) detector was used to acquire the data. The measured cross section data were corrected for gamma-ray attenuations, pulse pile-up effects, dead time, variations in neutron flux, and contributions from scattered low-energy neutrons. The measured cross sections were compared with statistical model calculations (TALYS 1.6 code), the experimental data available in the literature and the data obtained from TENDL. PMID:25728005

  2. Development of a measurement system for the determination of (n , γ) cross-sections using multi-nucleon transfer reactions

    NASA Astrophysics Data System (ADS)

    Makii, H.; Ota, S.; Ishii, T.; Wakabayashi, Y.; Furutaka, K.; Nishio, K.; Nishinaka, I.; Chiba, S.; Igashira, M.; Czeszumska, A.

    2015-10-01

    We have installed a new experimental apparatus to measure γ-rays from highly excited states populated by the multi-nucleon transfer reactions with heavy-ion projectiles to determine the (n, γ) cross-sections by means of the surrogate reaction method. An apparatus consists of two anti-Compton LaBr3(Ce) spectrometers to measure the γ-rays and a Si ΔE-E detector system to detect outgoing projectile-like particles. Reactions of 153-MeV 18O beams with 155Gd and 157Gd targets were used to study the performance of apparatus. By using the LaBr3(Ce) scintillators with relatively large volume (101.6 mm in diameter and 127 mm in length), we have successfully measured γ-rays from the compound nuclei, which have excitation energy above neutron separation energy, populated by 155Gd(18O, 16O)157Gd and 157Gd(18O, 16O)159Gd two-neutron transfer reactions. To measure in-beam γ-rays through heavy-ion-induced transfer reaction, it is important to assign the reaction channel clearly, since the cross-sections of the transfer reactions are much smaller than those of competing reactions such as Coulomb excitation and fusion reactions. The Si ΔE-E detector system was used to separate outgoing particles. The present study has demonstrated high capability of apparatus to measure the de-excitation γ-rays in the compound nuclei produced by the multi-nucleon transfer reactions for determination of the (n, γ) cross-sections by using the surrogate reaction method.

  3. 252Cf spectrum-averaged cross section for the 63Cu(n, p)63Ni reaction

    NASA Astrophysics Data System (ADS)

    Imamura, M.; Shibata, T.; Shibata, S.; Ohkubo, T.; Satoh, S.; Nogawa, N.

    1999-01-01

    The 63Ni produced by the 63Cu(n, p)63Ni reaction provides a unique measure to estimate the fast-neutron fluence of the Hiroshima/Nagasaki atomic bomb. In the similarity of the fission neutron spectrum of 252Cf to that of 235U, we have measured activation cross sections of the 63Cu(n, p)63Ni reaction averaged for the 252Cf fission spectrum.

  4. Cross sections of α-induced reactions for targets with masses A ≈ 20-50 at low energies

    NASA Astrophysics Data System (ADS)

    Mohr, Peter

    2015-05-01

    A simple reduction scheme using so-called reduced energies and reduced cross sections allows the comparison of heavy-ion-induced reaction cross sections for a broad range of masses of projectile and target and over a wide energy range. A global behavior has been found for strongly bound projectiles whereas much larger reduced cross sections have been observed for weakly bound and halo projectiles. It has been shown that this simple reduction scheme works also well for -particle-induced reactions on heavy target nuclei, but very recently significant deviations have been seen for + 33S and + 23Na. Motivated by these unexpected discrepancies, the present study analyses -induced reaction cross sections for targets with masses 20-50. The study shows that the experimental data for -induced reactions on nuclei with 20-50 deviate slightly from the global behavior of reduced cross sections. However, in general the deviations evolve smoothly towards lower masses. The only significant outliers are the recent data for 33S and 23Na which are far above the general systematics, and some very old data may indicate that 36Ar and 40Ar are below the general trend. As expected, also the doubly magic 40Ca nucleus lies slightly below the results for its neighboring nuclei. Overall, the experimental data are nicely reproduced by a statistical model calculation utilizing the simple -nucleus potential by McFadden and Satchler. Simultaneously with the deviation of reduced cross sections from the general behavior, the outliers 23Na, 33S, 36Ar, and 40Ar also show significant disagreement between experiment and statistical model calculation.

  5. Revised Calculations of the Production Rates for Co Isotopes in Meteorites Using New Cross Sections for Neutron-induced Reactions

    NASA Technical Reports Server (NTRS)

    Sisterson, J. M.; Brooks, F. D.; Buffler, A.; Allie, M. S.; Herbert, M. S.; Nchodu, M. R.; Makupula, S.; Ullmann, J.; Reedy, R. C.; Jones, D. T. L.

    2002-01-01

    New cross section measurements for reactions induced by neutrons with energies greater than 70 MeV are used to calculate the production rates for cobalt isotopes in meteorites and these new calculations are compared to previous estimates. Additional information is contained in the original extended abstract.

  6. Quantum state-resolved differential cross sections for complex-forming chemical reactions: Asymmetry is the rule, symmetry the exception

    SciTech Connect

    Larrégaray, Pascal Bonnet, Laurent

    2015-10-14

    We argue that statistical theories are generally unable to accurately predict state-resolved differential cross sections for triatomic bimolecular reactions studied in beam experiments, even in the idealized limit where the dynamics are fully chaotic. The basic reason is that quenching of interferences between partial waves is less efficient than intuitively expected, especially around the poles.

  7. Exact quantum cross sections for a three dimensional angle dependent model for three body reactions.

    NASA Technical Reports Server (NTRS)

    Baer, M.; Kouri, D. J.

    1971-01-01

    Exact quantum mechanical reactive cross sections are reported for a three dimensional angle dependent model surface. The surface simulates an atom-heteronuclear diatom system A + BC leading to AB + C where atom B is much heavier than A or C. The molecules BC and AB are taken to be rotating vibrators which can dissociate. Results for two angle dependent potentials are given.

  8. Determination of the cross section for nuclear reactions in complex nuclear decay chains.

    PubMed

    Adam, J; Balabekyan, A; Pronskikh, V S; Kalinnikov, V G; Mrázek, J

    2002-04-01

    In the present paper decays of genetically connected nuclei are considered and equations for their independent cross sections are derived. An optimisation parameter is proposed for an experiment where spectra of the residual nuclei are studied by the induced activity method. This parameter depends on irradiation time, delay time and spectrum measurement time. PMID:11999159

  9. 87Y(n,γ) and 89,90Zr(n,γ) cross sections from a surrogate reaction approach

    NASA Astrophysics Data System (ADS)

    Ota, Shuya; Burke, J. T.; Casperson, R. J.; Escher, J. E.; Hughes, R. O.; Ressler, J. J.; Scielzo, N. D.; Thompson, I.; Austin, R. A. E.; McCleskey, E.; McCleskey, M.; Saastamoinen, A.; Ross, T.

    2015-05-01

    The surrogate reaction approach is an indirect method for determining nuclear reaction cross sections which cannot be measured directly or predicted reliably. While recent studies demonstrated the validity of the surrogate reaction approach for studying fission cross sections for short-lived actinides, its applicability for radiative neutron capture reactions ((n,γ)) is still under investigation. We studied the γ decay of excited 88Y and 90,91Zr nuclei produced by 89Y(p,d), 91Zr(p,d), and 92Zr(p,d) reactions, respectively, in order to infer the 87Y(n,γ) and 89, 90Zr(n,γ) cross sections. The experiments were carried out at the K150 Cyclotron facility at Texas A&M University with a 28.5-MeV proton beam. The reaction deuterons were measured at forward angles of 25-60° with the array of three segmented Micron S2 silicon detectors. The compound nuclei with energies up to a few MeV above the neutron separation thresholds were populated. The coincident γ-rays were measured with the array of five Compton-suppressed HPGe clover detectors.

  10. Calculation and analysis of cross-sections for p+184W reactions up to 200 MeV

    NASA Astrophysics Data System (ADS)

    Sun, Jian-Ping; Zhang, Zheng-Jun; Han, Yin-Lu

    2015-08-01

    A set of optimal proton optical potential parameters for p+ 184W reactions are obtained at incident proton energy up to 250 MeV. Based on these parameters, the reaction cross-sections, elastic scattering angular distributions, energy spectra and double differential cross sections of proton-induced reactions on 184W are calculated and analyzed by using theoretical models which integrate the optical model, distorted Born wave approximation theory, intra-nuclear cascade model, exciton model, Hauser-Feshbach theory and evaporation model. The calculated results are compared with existing experimental data and good agreement is achieved. Supported by National Basic Research Program of China, Technology Research of Accelerator Driven Sub-critical System for Nuclear Waste Transmutation (2007CB209903) and Strategic Priority Research Program of Chinese Academy of Sciences, Thorium Molten Salt Reactor Nuclear Energy System (XDA02010100)

  11. Production cross section of At radionuclides from 7Li+natPb and 9Be+natTl reactions

    NASA Astrophysics Data System (ADS)

    Maiti, Moumita; Lahiri, Susanta

    2011-12-01

    Earlier we reported theoretical studies on the probable production of astatine radionuclides from 6,7Li- and 9Be-induced reactions on natural lead and thallium targets, respectively. The production of astatine radionuclides were investigated experimentally with two heavy-ion-induced reactions: 9Be + natTl and 7Li + natPb. Formation cross sections of the evaporation residues, 207,208,209,210At, produced in the (HI,xn) channel, were measured by the stacked-foil technique followed by off-line γ spectrometry at low incident energies (<50 MeV). Measured excitation functions were interpreted in terms of a compound nuclear reaction mechanism using Weisskopf-Ewing and Hauser-Feshbach models. Measured cross-section values are lower than the respective theoretical predictions.

  12. Influence of the neutron numbers of projectile and target on the evaporation residue cross sections in hot fusion reactions

    NASA Astrophysics Data System (ADS)

    Zhu, Long; Su, Jun; Zhang, Feng-Shou

    2016-06-01

    Within the framework of a dinuclear system model, the influence of projectile and target neutron number on capture cross section, fusion probability, and survival probability for the reactions S,3634+238U and 48Ca+Pu 239 ,240 ,242 ,244 are investigated. The calculated excitation functions are in good agreement with the experimental data. To synthesize more unknown neutron-deficient isotopes of already-known superheavy elements, the possibility of using lighter calcium isotopes to induce hot fusion reactions is investigated and the maximal evaporation residual cross sections for Ca 44 ,46 ,48 -induced hot fusion reactions to produce unknown neutron-deficient superheavy nuclei with Z =112 -116 are predicted.

  13. X-ray spectrometry applied to 14 MeV neutron reaction cross-section measurements on iridium

    NASA Astrophysics Data System (ADS)

    Reggoug, A.; Berrada, M.

    1987-03-01

    In the activation technique, the simultaneous measurement of cross-sections by detection of X-and γ-rays allows to compare the obtained results and also to check the available nuclear data used in each method. For residual nuclei which have very weak gamma intensity, the X-ray detection becomes the most adequate method for cross section measurements. It is the case of 193Ir(n,2n) 192m 1Ir (1.45 min) and 191Ir (n,2n) 190m 1Ir (1.2 h) reactions where the residual nuclei have an almost absent gamma intensity. We have measured for the first time the cross section ratio of these reactions by detecting the L X-rays emitted by both residual nuclei. Cross section of reactions 191Ir(n,2n) 190m 2Ir (3.2 h); 191Ir(n,2n) 190m+gIr(11.8 d) and 193Ir(n,2n) 192m+gIr (74 d), where the residual nuclei emit simultaneously X and gamma rays, have been measured by K X-rays detection and compared to other reported values.

  14. Measurement of the Differential Cross Section for the Reaction γn→π-p from Deuterium

    NASA Astrophysics Data System (ADS)

    Chen, W.; Mibe, T.; Dutta, D.; Gao, H.; Laget, J. M.; Mirazita, M.; Rossi, P.; Stepanyan, S.; Strakovsky, I. I.; Amaryan, M. J.; Anghinolfi, M.; Bagdasaryan, H.; Battaglieri, M.; Bellis, M.; Berman, B. L.; Biselli, A. S.; Bookwalter, C.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Careccia, S. L.; Carman, D. S.; Casey, L.; Cole, P. L.; Collins, P.; Crede, V.; Daniel, A.; Dashyan, N.; de Vita, R.; de Sanctis, E.; Deur, A.; Dhamija, S.; Dickson, R.; Djalali, C.; Dodge, G. E.; Doughty, D.; Egiyan, H.; Eugenio, P.; Fedotov, G.; Fradi, A.; Garçon, M.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gohn, W.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Hakobyan, H.; Hanretty, C.; Hassall, N.; Heddle, D.; Hicks, K.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jo, H. S.; Johnstone, J. R.; Joo, K.; Keller, D.; Khandaker, M.; Khetarpal, P.; Kim, W.; Klein, A.; Klein, F. J.; Kramer, L. H.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Kuznetsov, V.; Livingston, K.; Lu, H. Y.; Markov, N.; McCracken, M. E.; McKinnon, B.; Meyer, C. A.; Mineeva, T.; Mokeev, V.; Moreno, B.; Moriya, K.; Nadel-Turonski, P.; Nasseripour, R.; Niccolai, S.; Niculescu, I.; Niroula, M. R.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Park, S.; Pereira, S. Anefalos; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Raue, B. A.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Sabatié, F.; Saini, M. S.; Salamanca, J.; Salgado, C.; Schumacher, R. A.; Sharabian, Y. G.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Strauch, S.; Taiuti, M.; Tedeschi, D. J.; Tkachenko, S.; Ungaro, M.; Vineyard, M. F.; Watts, D. P.; Weinstein, L. B.; Weygand, D. P.; Wood, M. H.; Yegneswaran, A.; Zhang, J.; Zhao, B.

    2009-07-01

    We report a measurement of the differential cross section for the γn→π-p process from the CLAS detector at Jefferson Laboratory in Hall B for photon energies between 1.0 and 3.5 GeV and pion center-of-mass (c.m.) angles (θc.m.) between 50° and 115°. We confirm a previous indication of a broad enhancement around a c.m. energy (s) of 2.1 GeV at θc.m.=90° in the scaled differential cross section s7(dσ)/(dt) and a rapid falloff in a center-of-mass energy region of about 400 MeV following the enhancement. Our data show an angular dependence of this enhancement as the suggested scaling region is approached for θc.m. from 70° to 105°.

  15. Neutral Current Neutrino-{sup 116}Cd Reaction Cross Sections at Low and Intermediate Energies

    SciTech Connect

    Balasi, K. G.; Kosmas, T. S.; Divari, P. C.; Chasioti, V. C.

    2008-01-24

    Differential and integrated cross sections for inelastic scattering of electron neutrinos from a {sup 116}Cd target at low and intermediate neutrino energies ({epsilon}{sub i}{<=}100 MeV) are presented. The nuclear wave functions for the initial and final nuclear states are constructed in the context of quasiparticle random phase approximation (QRPA). By exploiting the results of these cross sections, we study the response of {sup 116}Cd to supernova neutrino spectra by utilizing the folding procedure and employing a two-parameter Fermi-Dirac distribution for the supernova neutrino spectra. Our results show that, this isotope may play a significant role in supernova neutrino detection, in addition to its use in double-beta-decay experiments (COBRA, etc)

  16. Measurements of 10B(p,a)7Be Cross-sections: A Reaction Relevant to Nuclear Fusion Energy Research

    NASA Astrophysics Data System (ADS)

    Fisher, Barbara; Kafkarkou, Adamos; Ahmed, Mohammad; Weller, Henry; Myers, Luke; Sparker, Mark; Zimmerman, William; Mueller, Jon; Sikora, Mark; Mazumdar, Indral

    2012-10-01

    There is growing interest in aneutronic nuclear fusion reactors. One facility proposes to utilize the 11B(p,a)7Be reaction. The Radiative Capture Group at Triangle University Nuclear Laboratory (TUNL) has been engaged in a long-term study of this and related reactions. This poster will present preliminary data and analysis of the 10B(p,a)7Be reaction which is of interest because 10B is a potential reactor contaminant. Differential and total cross-sections will be presented for incident protons of 4.4 and 4.6 MeV. The data is necessary for simulations of an aneutrionic nuclear fusion reactor.

  17. Systematic Studies of (n,p) Reaction Cross Sections for 14.5 MeV Neutrons

    SciTech Connect

    Belgaid, M.; Kadem, F.; Arezki, A.

    2006-04-26

    A new semi-empirical formula for the calculation of the (n,p) cross section at 14.5 MeV neutron energy is obtained. Derived from the evaporation statistical model, the new formula includes five parameters and shows for the first times a strong dependence of the (n,p) cross section on terms of the parameter (2Z-1)/A. Fitting this formula to the existing cross section data on 161 nuclei with 40{<=}A{<=}209, the adjustable parameters have been determined and the systematics of the (n,p) reaction have been studied. The predictions of this formula are compared with those of the existing formulae and with the experimental data. The formula with five parameters is found to give a better fit to the data than the previous comparable formulae.

  18. Dielectron Cross Section Measurements in Nucleus-Nucleus Reactions at 1.0{ital A} GeV

    SciTech Connect

    Porter, R.J.; Bossingham, R.; Gong, W.G.; Heilbronn, L.; Huang, H.Z.; Krebs, G.; Letessier-Selvon, A.; Matis, H.S.; Miller, J.; Naudet, C.; Roche, G.; Schroeder, L.S.; Seidl, P.; Wilson, W.K.; Yegneswaran, A.; Beedoe, S.; Carroll, J.; Huang, H.Z.; Igo, G.; Bougteb, M.; Manso, F.; Prunet, M.; Roche, G.; Kirk, P.; Wang, Z.F.; Wilson, W.K.

    1997-08-01

    We present measured dielectron production cross sections for Ca+Ca, C+C, He+Ca, and d+Ca reactions at 1.0 A GeV . Statistical uncertainties and systematic effects are smaller than in previous dilepton spectrometer (DLS) nucleus-nucleus data. For pair mass M{le}0.35 GeV/c{sup 2} we obtain (1) the Ca+Ca cross section is larger than the previous DLS measurement and current model results, (2) the mass spectra suggest large contributions from {pi}{sup 0} and {eta} Dalitz decays, and (3) d{sigma}/dM{proportional_to}A{sub P}A{sub T}. For M{gt}0.5 GeV/c{sup 2} the Ca+Ca to C+C cross section ratio is significantly larger than the ratio of A{sub P}A{sub T} values. {copyright} {ital 1997} {ital The American Physical Society}

  19. Integral cross section measurement of the U 235 ( n , n ' ) U 235 m reaction in a pulsed reactor

    DOE PAGESBeta

    Bélier, G.; Bond, E. M.; Vieira, D. J.; Authier, N.; Becker, J. A.; Hyneck, D.; Jacquet, X.; Jansen, Y.; Legendre, J.; Macri, R.; et al

    2015-04-08

    The integral measurement of the neutron inelastic cross section leading to the 26-minute half-life 235mU isomer in a fission-like neutron spectrum is presented. The experiment has been performed at a pulsed reactor, where the internal conversion decay of the isomer was measured using a dedicated electron detector after activation. The sample preparation, efficiency measurement, irradiation, radiochemistry purification, and isomer decay measurement will be presented. We determined the integral cross section for the ²³⁵U(n,n')235mU reaction to be 1.00±0.13b. This result supports an evaluation performed with TALYS-1.4 code with respect to the isomer excitation as well as the total neutron inelastic scatteringmore » cross section.« less

  20. Measurement of 55Fe(n ,p ) cross sections by the surrogate-reaction method for fusion technology applications

    NASA Astrophysics Data System (ADS)

    Pandey, Bhawna; Desai, V. V.; Suryanarayana, S. V.; Nayak, B. K.; Saxena, A.; Mirgule, E. T.; Santra, S.; Mahata, K.; Makawana, R.; Abhangi, M.; Basu, T. K.; Rao, C. V. S.; Jakhar, S.; Vala, S.; Sarkar, B.; Agrawal, H. M.; Kaur, G.; Prajapati, P. M.; Pal, Asim; Sarkar, D.; Kundu, A.

    2016-02-01

    We have measured the proton decay probabilities of the *56Fe and *47Ti compound systems which are populated by the transfer reactions 52Cr(6Li,d ) *56Fe (surrogate of n +55Fe→*56Fe→p +55Mn ) and 45Sc(6Li,α ) *47Ti (surrogate of n +46Ti→47Ti*→p +46Sc ) reactions, respectively. The 55Fe(n ,p ) cross sections were then obtained in the equivalent neutron energy range of 7.9 to 20.1 MeV within the framework of the surrogate-reaction method. The measured results were compared with predictions of the empire-3.2.3 statistical model code and various recent evaluated data libraries. The experimental cross-section data on 55Fe(n ,p ) are in reasonable agreement with EAF-2010, while the TENDL-2014 and ROSFOND-2010 data show some discrepancies. This study demonstrates the possibility of determining neutron-induced charged particle emission cross sections for unstable radionuclides relevant to fusion technology applications by the surrogate-reaction method.

  1. Activation evaluation and isotopic effects in the (n, p) reaction cross section on A-180 target nuclei

    SciTech Connect

    Avrigeanu, M.; Forrest, R. A.; Roman, F. L.; Avrigeanu, V.

    2006-07-01

    The fast-neutron nuclear data for the stable isotopes of tungsten, tantalum and hafnium, which are important in nuclear technology applications, have been consistently analyzed by means of the nuclear model computer codes TALYS, EMPIRE-II and STAPRE-H. The latter code uses a unique parameter set. The long-lived Hf isomers, which could be produced after a few reactions on W and Ta in the first-wall material of fusion power plants, need special consideration. The analysis, making use of global as well as local parameters within different model assumptions, aims to increase the predictive power of the models, which is of interest to basic as well as applied questions. This work suggests a physical reason for some of the discrepancies between experimental and calculated cross sections for (n, p) and (n, {alpha}) reactions on {sup 181}Ta. Thus, the rather similar Q-values for the (n, p) reaction on the {sup 179}Hf, {sup 181}Ta, and {sup 183}W odd-A target nuclei, also with similar asymmetry-parameter values, support the comparable cross sections which are predicted by all three computer code calculations at variance with the lower measured cross sections of the {sup 181}Ta(n, p) {sup 181}Hf reaction. (authors)

  2. The Study of ( n,d) Reaction Cross Sections for Some Medium Weight Targets up to 30 MeV

    NASA Astrophysics Data System (ADS)

    Aydin, A.; Şahan, M.; Tel, E.; Şahan, H.; Uğur, F. A.

    2011-08-01

    In this study, neutron incident reaction cross sections for some medium target nuclei ( 44 Ca, 65 Cu, 54 Fe, 56 Fe, 57 Fe, 58 Ni, 60 Ni and 67 Zn) have been investigated for the ( n,d) reaction cross sections. These new calculations on the excitation functions of 44 Ca(n,d) 43 K, 65 Cu(n,d) 44 Ni, 54 Fe(n,d) 53 Mn, 56 Fe(n,d) 55 Mn, 57 Fe(n,d) 56 Mn, 58 Ni(n,d) 57 Co, 60 Ni(n,d) 59 Co and 67 Zn(n,d) 66 Cu reactions have been carried out up to 30 MeV incident neutron energy. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The PEQ calculations involve the new evaluated the Geometry Dependent Hybrid model. Equilibrium effects are calculated according to the Weisskopf-Ewing model. By using the new cross sections formulae for ( n,d) reactions developed by Aydin et al., the obtained results have been discussed and compared with the available experimental data taken from EXFOR database.

  3. Cross section measurements of the B10(d,n0)C11 reaction below 160 keV

    NASA Astrophysics Data System (ADS)

    Stave, S.; Ahmed, M. W.; Antolak, A. J.; Blackston, M. A.; Crowell, A. S.; Doyle, B. L.; Henshaw, S. S.; Howell, C. R.; Kingsberry, P.; Perdue, B. A.; Rossi, P.; Prior, R. M.; Spraker, M. C.; Weller, H. R.

    2008-05-01

    New data were taken at the Triangle Universities Nuclear Laboratory to investigate the plausibility of using low energy deuterons and the B10(d,n)C11 reaction as a portable source of 6.3 MeV neutrons. Analysis of the data at and below incident deuteron energies of 160 keV indicates an n0 neutron cross section that is lower than previous estimates by at least three orders of magnitude. In separate runs, deuterons with two different energies (160 and 140 keV) were stopped in a B10 target. The resulting n0 neutrons of approximately 6.3 MeV were detected at angles between 0° and 150°. The angle integrated yields were used to determine the astrophysical S factor for this reaction assuming a constant value for the S factor below 160 keV. The cross sections reported between 130 and 160 keV were calculated using the extracted value of the S factor. The measured n0 cross section is several orders of magnitude smaller than previous results, thus eliminating B10(d,n)C11 as a portable source of intense neutrons with low energy deuteron beams on the order of tens of microamps. In order to gain insight into the reaction dynamics at these low energies the cross section results have been compared with results from calculations using the distorted wave Born approximation (DWBA) and a detailed Hauser-Feshbach calculation performed by the authors. The angular distribution is consistent with the Hauser-Feshbach calculation suggesting a statistical compound nucleus reaction rather than a direct reaction.

  4. Differential cross sections measurement of 31P(p,pγ1)31P reaction for PIGE applications

    NASA Astrophysics Data System (ADS)

    Jokar, A.; Kakuee, O.; Lamehi-Rachti, M.

    2016-09-01

    Differential cross sections of proton induced gamma-ray emission from the 31P(p,pγ1)31P (Eγ = 1266 keV) nuclear reaction were measured in the proton energy range of 1886-3007 keV at the laboratory angle of 90°. For these measurements a thin Zn3P2 target evaporated onto a self-supporting C film was used. The gamma-rays and backscattered protons were detected simultaneously. An HPGe detector placed at an angle of 90° with respect to the beam direction was employed to collect gamma-rays while an ion implanted Si detector placed at a scattering angle of 165° was used to detect backscattered protons. Simultaneous collection of gamma-rays and RBS spectra is a great advantage of this approach which makes differential cross-section measurements independent on the collected beam charge. The obtained cross-sections were compared with the previously only measured data in the literature. The validity of the measured differential cross sections was verified through a thick target benchmarking experiment. The overall systematic uncertainty of cross section values was estimated to be better than ±9%.

  5. Inclusive proton spectra and total reaction cross sections for proton-nucleus scattering at 800 MeV

    SciTech Connect

    McGill, J.A.

    1981-08-01

    Current applications of multiple scattering theory to describe the elastic scattering of medium energy protons from nuclei have been shown to be quite successful in reproducing the experimental cross sections. These calculations use the impulse approximation, wherein the scattering from individual nucleons in the nucleus is described by the scattering amplitude for a free nucleon. Such an approximation restricts the inelastic channels to those initiated by nucleon-nucleon scattering. As a first step in determining the nature of p + nucleus scattering at 800 MeV, both total reaction cross sections and (p,p') inclusive cross sections were measured and compared to the free p + p cross sections for hydrogen, deuterium, calcium 40, carbon 12, and lead 208. It is concluded that as much as 85% of all reactions in a nucleus proceed from interactions with a single nucleon in the nucleus, and that the impulse approximation is a good starting point for a microscopic description of p + nucleus interactions at 800 MeV.

  6. Measurement of 235U(n,n'γ) and 235U(n,2nγ) reaction cross sections

    NASA Astrophysics Data System (ADS)

    Kerveno, M.; Thiry, J. C.; Bacquias, A.; Borcea, C.; Dessagne, P.; Drohé, J. C.; Goriely, S.; Hilaire, S.; Jericha, E.; Karam, H.; Negret, A.; Pavlik, A.; Plompen, A. J. M.; Romain, P.; Rouki, C.; Rudolf, G.; Stanoiu, M.

    2013-02-01

    The design of generation IV nuclear reactors and the studies of new fuel cycles require knowledge of the cross sections of various nuclear reactions. Our research is focused on (n,xnγ) reactions occurring in these new reactors. The aim is to measure unknown cross sections and to reduce the uncertainty on present data for reactions and isotopes of interest for transmutation or advanced reactors. The present work studies the 235U(n,n'γ) and 235U(n,2nγ) reactions in the fast neutron energy domain (up to 20 MeV). The experiments were performed with the Geel electron linear accelerator GELINA, which delivers a pulsed white neutron beam. The time characteristics enable measuring neutron energies with the time-of-flight (TOF) technique. The neutron induced reactions [in this case inelastic scattering and (n,2n) reactions] are identified by on-line prompt γ spectroscopy with an experimental setup including four high-purity germanium (HPGe) detectors. A fission ionization chamber is used to monitor the incident neutron flux. The experimental setup and analysis methods are presented and the model calculations performed with the TALYS-1.2 code are discussed.

  7. Importance of level structure in nuclear reaction cross-section calculations. Revision 1

    SciTech Connect

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

    1985-11-07

    It is shown that level-density expressions cannot adequately represent or substitute for level structure information when making calculations of the Hauser-Feshbach type for cross sections or isomer-ratios for nuclei in the first few MeV above their ground state. It is stated that such discrete level information should include both experimentally confirmed and theoretically predicted levels. The utility of discrete level information to optimize level density calculations, to compute isomer ratios, in deriving dipole strength functions, and in the analysis of primary gamma ray spectra is emphasized, especially for nuclei far from the line of stability. 29 refs., 12 figs., 6 tabs. (DWL)

  8. Probing dynamics of fusion reactions through cross-section and spin distribution measurement

    NASA Astrophysics Data System (ADS)

    Kaur, Maninder; Behera, B. R.; Singh, Gulzar; Singh, Varinderjit; Madhavan, N.; Muralithar, S.; Nath, S.; Gehlot, J.; Mohanto, G.; Mukul, Ish; Siwal, D.; Thakur, M.; Kapoor, K.; Sharma, P.; Banerjee, T.; Jhingan, A.; Varughese, T.; Bala, Indu; Nayak, B. K.; Saxena, A.; Chatterjee, M. B.; Stevenson, P. D.

    2016-05-01

    Present work aims to explicate the effect of entrance channel mass asymmetry on fusion dynamics for the Compound Nucleus 80Sr populated through two different channels, 16O+64Zn and 32S+48Ti, using cross-section and spin distribution measurements as probes. The evaporation spectra studies for these systems, reported earlier indicate the presence of dynamical effects for mass symmetric 32S+48Ti system.The CCDEF and TDHF calculations have been performed for both the systems and an attempt has been made to explain the reported deviations in the α-particle spectrum for the mass symmetric system.

  9. Experimental differential cross sections, level densities, and spin cutoffs as a testing ground for nuclear reaction codes

    DOE PAGESBeta

    Voinov, Alexander V.; Grimes, Steven M.; Brune, Carl R.; Burger, Alexander; Gorgen, Andreas; Guttormsen, Magne; Larsen, Ann -Cecilie; Massey, Thomas N.; Siem, Sunniva

    2013-11-08

    Proton double-differential cross sections from 59Co(α,p)62Ni, 57Fe(α,p)60Co, 56Fe(7Li,p)62Ni, and 55Mn(6Li,p)60Co reactions have been measured with 21-MeV α and 15-MeV lithium beams. Cross sections have been compared against calculations with the empire reaction code. Different input level density models have been tested. It was found that the Gilbert and Cameron [A. Gilbert and A. G. W. Cameron, Can. J. Phys. 43, 1446 (1965)] level density model is best to reproduce experimental data. Level densities and spin cutoff parameters for 62Ni and 60Co above the excitation energy range of discrete levels (in continuum) have been obtained with a Monte Carlo technique. Furthermore,more » excitation energy dependencies were found to be inconsistent with the Fermi-gas model.« less

  10. Differential cross section measurements for the 6Li(n,t)alpha reaction in the few MeV region

    SciTech Connect

    Devlin, Matthew J; Taddeucci, Terence N; Hale, Gerald M; Haight, Robert C; O' Donnell, Johhn M

    2008-01-01

    New measured differential cross sections of tritons and alpha particles following the {sup 6}Li(n,t){alpha} reaction are reported for incident neutron energies between 0.2 and approximately 20 MeV. The neutrons were produced by spallation at the WNR facility at the Los Alamos Neutron Science CEnter (LANSCE), with the incident neutron energy determined by the time-of-flight method. Four E-{Delta}E telescopes were used at eight laboratory angles. These data have been incorporated into a prior R-matrix fit for the compound {sup 7}Li system, and result in an (n,t) reaction cross section that is 4% to 10% higher than previous evaluations in the 1-3 MeV incident neutron energy region.

  11. Systematics Studies of (n,{alpha}) reaction cross sections at 14.5 MeV neutrons energy

    SciTech Connect

    Belgaid, M.; Kadem, F.; Amokrane, A.

    2008-05-12

    A new semi-empirical formula for the calculation of the (n,{alpha}) cross section at 14.5 MeV neutron energy is obtained. It is based on the pre-equilibrium exciton and evaporation models and uses the Droplet model of Myers and Swiatecki to express the reaction energy Q(n,{alpha}). The systematics behavior of the different terms of the Droplet model involved in Q(n,{alpha}) was checked individually before choosing the pertinent terms and setting up the formula. Fitting this formula to the existing cross section data on 120 nuclei with 40{<=}A{<=}209, the adjustable parameters have been determined and the systematics of the (n,{alpha}) reaction have been studied. The predictions of this formula are compared with those of the existing formulae and with the experimental data. The formula with five parameters is found to give a better fit to the data than the previous comparable formulae.

  12. Production cross-sections of radionuclides from α-induced reactions on natural copper up to 50MeV.

    PubMed

    Usman, Ahmed Rufai; Khandaker, Mayeen Uddin; Haba, Hiromitsu; Otuka, Naohiko; Murakami, Masashi; Komori, Yukiko

    2016-08-01

    The excitation functions were measured for the (nat)Cu(α,x)(66,67)Ga,(65)Zn,(57,58,60)Co reactions in the energy range of 16.5 -50MeV. A conventional stacked-foil activation technique combined with HPGe γ-ray spectrometry was employed to determine cross-sections. The measured cross-sections were critically compared with relevant previous experimental data and also with the evaluated data in the TENDL-2014 library. Present results confirmed some of the previous experimental data, whereas only a partial agreement was found with the evaluated data. The measured data are useful for reducing the existing discrepancies in the literature, to improve the nuclear reaction model codes, and to enrich the experimental database towards various applications. PMID:27227905

  13. Activation cross-sections of deuteron induced reactions on natSm up to 50 MeV

    NASA Astrophysics Data System (ADS)

    Tárkányi, F.; Hermanne, A.; Takács, S.; Ditrói, F.; Csikai, J.; Ignatyuk, A. V.

    2014-08-01

    Activation cross-sections for deuteron induced reactions on Sm are presented for the first time for natSm(d,xn)155,154,152m2,152m1,152g,150m,150g,149,148,147,146Eu, natSm(d,x) 153,145Sm and natSm(d,x)151,150,149,145,144,143Pm up to 50 MeV. The cross-sections were measured by the stacked-foil irradiation technique and high resolution γ-ray spectrometry. The results were compared with results of nuclear reaction codes ALICE-D, EMPIRE-D and TALYS (from TENDL libraries). Integral yields of the products were calculated from the excitation functions.

  14. Activation cross-sections of proton induced reactions on natSm up to 65 MeV

    NASA Astrophysics Data System (ADS)

    Tárkányi, F.; Hermanne, A.; Takács, S.; Ditrói, F.; Ignatyuk, A. V.

    2015-03-01

    Activation cross sections for proton induced reactions on Sm are presented for the first time for natSm(p,xn)154,152m2,152m1,152g,150m,150g,149,148,147,146,145Eu, natSm(p,x)153,145Sm, natSm(p,x)151,150,149,148g,148m,146,144,143Pm and natSm(p,x)141Nd up to 65 MeV. The cross sections were measured via activation method by using a stacked-foil irradiation technique and high resolution gamma ray spectroscopy. The results were compared with results of the nuclear reaction codes ALICE, EMPIRE and TALYS (results taken from TENDL libraries). Integral yields of the activation products were calculated from the excitation functions.

  15. Experimental differential cross sections, level densities, and spin cutoffs as a testing ground for nuclear reaction codes

    NASA Astrophysics Data System (ADS)

    Voinov, A. V.; Grimes, S. M.; Brune, C. R.; Bürger, A.; Görgen, A.; Guttormsen, M.; Larsen, A. C.; Massey, T. N.; Siem, S.

    2013-11-01

    Proton double-differential cross sections from 59Co(α,p)62Ni, 57Fe(α,p)60Co, 56Fe(7Li,p)62Ni, and 55Mn(6Li,p)60Co reactions have been measured with 21-MeV α and 15-MeV lithium beams. Cross sections have been compared against calculations with the empire reaction code. Different input level density models have been tested. It was found that the Gilbert and Cameron [A. Gilbert and A. G. W. Cameron, Can. J. Phys.0008-420410.1139/p65-139 43, 1446 (1965)] level density model is best to reproduce experimental data. Level densities and spin cutoff parameters for 62Ni and 60Co above the excitation energy range of discrete levels (in continuum) have been obtained with a Monte Carlo technique. Excitation energy dependencies were found to be inconsistent with the Fermi-gas model.

  16. Influence of collision energy and reagent rotation on the cross sections and product polarizations of the reaction F+ HCl

    NASA Astrophysics Data System (ADS)

    Duan, Zhi Xin; Li, Wen Liang; Qiu, Ming Hui

    2012-04-01

    Quasiclassical trajectory calculations have been carried out for the F+HCl reaction in three dimensions on a recent DHSN PES of the ground 12A' electronic state [M. P. Deskevich, M. Y. Hayes, K. Takahashi, R. T. Skodje, and D. J. Nesbitt, J. Chem. Phys. 124, 224303 (2006)]. The effects of the collision energy and the reagent initial rotational excitation on the cross sections and product polarization are studied for the v = 0 and j ⩽ 10 states of HCl over a wide collision energy range. It has been found that either the collision energy or the HCl rotational excitation increase remarkably reaction cross sections. The QCT-calculated integral cross sections are in good agreement with previous QM results. A detailed study on product polarization for the title reaction is also performed. The calculated results show that the product rotational angular momentum j' is not only aligned, but also oriented along the direction perpendicular to the scattering plane. The orientation of the HF product rotational angular momentum vector j' depends very sensitively on the collision energy and also affected by the reagent rotation. The theoretical findings and especially the roles of the collision energy and initial rotational momentum on the product polarization are discussed and reasonably explained by the HLH mass combination, the property of the PES, as well as the reactive mechanism.

  17. Measurement of activation cross-sections for high-energy neutron-induced reactions of Bi and Pb

    NASA Astrophysics Data System (ADS)

    Zaman, Muhammad; Kim, Guinyun; Kim, Kwangsoo; Naik, Haladhara; Shahid, Muhammad; Lee, Manwoo

    2015-08-01

    The cross-sections for 209Bi(n, 4n)206Bi, 209Bi(n, 5n)205Bi, natPb(n, xn)204mPb, natPb(n, xn)203Pb, natPb(n, xn)202mPb,natPb(n, xn)201Pb, natPb(n, xn)200Pb, natPb(n, αxn)203Hg and natPb(n, p xn)202Tl reactions were determined at the Korean Institute of Radiological and Medical Sciences (KIRAMS), Korea in the neutron energy range of 15.2 to 37.2 MeV. The above cross-sections were obtained by using the activation and off-line γ-ray spectrometric technique. The quasi-monoenergetic neutron used for the above reactions are based on the 9Be(p, n) reaction. Simulations of the spectral flux from the Be target were done using the MCNPX program. The cross-sections were estimated with the TALYS 1.6 code using the default parameter. The data from the present work and literature were compared with the data from the EAF-2010 and the TENDL-2013 libraries, and calculated values of TALYS 1.6 code. It shows that appropriate level density model, the γ-ray strength function, and the spin cut-off parameter are needed to obtain a good agreement between experimental data and theoretical values from TALYS 1.6 code.

  18. Thulium-169 neutron inelastic scattering cross section measurements via the (169)Tm(n,n'gamma) reaction

    NASA Astrophysics Data System (ADS)

    Ko, Young June

    1999-11-01

    A neutron inelastic scattering study for low-lying states of thulium-169 below 1 MeV has been pursued by the detection of gamma rays from the 169Tm(n,n'γ) reaction. The inelastic level cross sections, which are important to obtain nuclear potential parameters and to understand reaction mechanisms, were obtained in this study. Incident neutrons were generated by bombarding a metallic lithium target with protons from the Lowell Van de Graaff accelerator. A germanium detector was used for gamma-ray observation. Excitation functions were measured from 0.2 to 1 MeV in 50 keV intervals at a scattering angle of 125°. Gamma-ray production cross sections were obtained for 37 observed transitions from 16 levels. Gamma-ray angular distributions from 35° to 135°, in 10° steps were measured at a neutron energy of 750 keV. The angular distributions were fitted with Legendre polynomials of even (up to fourth) order. Neutron inelastic level cross sections were inferred from the excitation functions and the angular distributions. Because cross-section data from previous experimental or theoretical work were not available, no direct comparison with previous work was made. A comparison of the magnitude and behavior of the (n,inelastic) cross section for thulium with those of neighboring odd-A nuclei indicated reasonable agreement. A classical model for angular momentum transfer indicates that states with spin >=/(+) may be excited only through the compound nucleus process, but for states with spin <=/(-) compound nucleus and direct interaction processes may both participate in the excitation.

  19. Differential cross sections and recoil polarizations for the reaction γp→K+Σ0

    DOE PAGESBeta

    Dey, B.; Meyer, C. A.; Bellis, M.; McCracken, M. E.; Williams, M.; Adhikari, K. P.; Aghasyan, M.; Anghinolfi, M.; Ball, J.; Battaglieri, M.; et al

    2010-08-06

    Here, high-statistics measurements of differential cross sections and recoil polarizations for the reactionmore » $$\\gamma p \\rightarrow K^+ \\Sigma^0$$ have been obtained using the CLAS detector at Jefferson Lab. We cover center-of-mass energies ($$\\sqrt{s}$$) from 1.69 to 2.84 GeV, with an extensive coverage in the $K^+$ production angle. Independent measurements were made using the $$K^{+}p\\pi^{-}$$($$\\gamma$$) and $$K^{+}p$$($$\\pi^-,\\gamma$$) final-state topologies, and were found to exhibit good agreement. Our differential cross sections show good agreement with earlier CLAS, SAPHIR and LEPS results, while offering better statistical precision and a 300-MeV increase in $$\\sqrt{s}$$ coverage. Above $$\\sqrt{s} \\approx 2.5$$ GeV, $t$- and $u$-channel Regge scaling behavior can be seen at forward- and backward-angles, respectively. Our recoil polarization ($$P_\\Sigma$$) measurements represent a substantial increase in kinematic coverage and enhanced precision over previous world data. At forward angles we find that $$P_\\Sigma$$ is of the same magnitude but opposite sign as $$P_\\Lambda$$, in agreement with the static SU(6) quark model prediction of $$P_\\Sigma \\approx -P_\\Lambda$$. This expectation is violated in some mid- and backward-angle kinematic regimes, where $$P_\\Sigma$$ and $$P_\\Lambda$$ are of similar magnitudes but also have the same signs. In conjunction with several other meson photoproduction results recently published by CLAS, the present data will help constrain the partial wave analyses being performed to search for missing baryon resonances.« less

  20. (p,α) Reaction Cross Sections Calculations of Fe and Ni Target Nuclei Using New Developed Semi-empirical Formula

    NASA Astrophysics Data System (ADS)

    Tel, E.; Akca, S.; Kara, A.; Yiğit, M.; Aydın, A.

    2013-10-01

    Iron (Fe) and nickel (Ni) are important fusion structural materials in reactor technology. The gas production in the metallic structure arising from many different types of nuclear reactions has been a significant damage mechanism in structural components of fusion reactors. The hydrogen and its isotopes at high temperatures leave out of the metallic lattice but the alpha (α) particles that remain in the lattice generate helium (He) gas bubbles. In other words, the α particles can cause serious changes in the physical and mechanical properties of the fusion structural materials. In this study, the excitation functions of 54,57Fe(p,α) and 58,60,61,64Ni(p,α) reactions have been investigated in the incident proton energy range of 10-40 MeV to estimate the radiation damage effects on fusion structural materials used in the construction of the first walls and core of the reactor. The calculations of (p,α) reaction cross sections on 54,57Fe and 58,60,61,64Ni have been made by using PCROSS code and CEM95 code. The full exciton and cascade exciton model (CEM95) for pre-equilibrium calculations and Weisskopf-Ewing model for equilibrium calculations are used. Besides, the semi-empirical cross section formula with new coefficient obtained by Tel et al. (Pramana J Phys 74:931-943, 2010) has been applied for (p,α) reactions at 17.9 MeV proton incident energy.

  1. Hypernuclear production cross section in the reaction of 6Li + 12C at 2 A GeV

    NASA Astrophysics Data System (ADS)

    Rappold, C.; Saito, T. R.; Bertini, O.; Bianchin, S.; Bozkurt, V.; Kim, E.; Kavatsyuk, M.; Ma, Y.; Maas, F.; Minami, S.; Nakajima, D.; Özel-Tashenov, B.; Yoshida, K.; Achenbach, P.; Ajimura, S.; Aumann, T.; Ayerbe Gayoso, C.; Bhang, H. C.; Caesar, C.; Erturk, S.; Fukuda, T.; Göküzüm, B.; Guliev, E.; Hoffmann, J.; Ickert, G.; Ketenci, Z. S.; Khaneft, D.; Kim, M.; Kim, S.; Koch, K.; Kurz, N.; Le Fèvre, A.; Mizoi, Y.; Nungesser, L.; Ott, W.; Pochodzalla, J.; Sakaguchi, A.; Schmidt, C. J.; Sekimoto, M.; Simon, H.; Takahashi, T.; Tambave, G. J.; Tamura, H.; Trautmann, W.; Voltz, S.; Yoon, C. J.

    2015-07-01

    Hypernuclear production cross sections have been deduced for the first time with induced reaction of heavy ion beam on fixed target and by means of the invariant mass method by the HypHI Collaboration exploiting the reaction of 6Li + 12C at 2 A GeV or √{sNN} = 2.70 GeV. A production cross section of 3.9 ± 1.4 μb for 3ΛH and of 3.1 ± 1.0 μb for 4ΛH respectively in the projectile rapidity region was inferred as well as the total production cross section of the Λ hyperon was measured and found to be equal to 1.7 ± 0.8 mb. A global fit based on a Bayesian approach was performed in order to include and propagate statistical and systematic uncertainties. Production ratios of 3ΛH/4ΛH, 3ΛH/Λ and 4ΛH/Λ were included in the inference procedure. The strangeness population factors S3 and S4 of 3ΛH and 4ΛH respectively were extracted. In addition, the multiplicities of the Λ hyperon, 3ΛH, and 4ΛH together with the rapidity and transversal momentum density distributions of the observed hypernuclei were extracted and reported.

  2. Elastic scattering and total reaction cross sections for the B8, Be7, and Li6 +12C systems

    NASA Astrophysics Data System (ADS)

    Barioni, A.; Zamora, J. C.; Guimarães, V.; Paes, B.; Lubian, J.; Aguilera, E. F.; Kolata, J. J.; Roberts, A. L.; Becchetti, F. D.; Villano, A.; Ojaruega, M.; Jiang, H.

    2011-07-01

    Angular distributions for the elastic scattering of B8, Be7, and Li6 on a C12 target have been measured at Elab=25.8, 18.8, and 12.3 MeV, respectively. The analyses of these angular distributions have been performed in terms of the optical model using Woods-Saxon and double-folding type potentials. The effect of breakup in the elastic scattering of 8B+12C is investigated by performing coupled-channels calculations with the continuum discretized coupled-channel method and cluster-model folding potentials. Total reaction cross sections were deduced from the elastic-scattering analysis and compared with published data on elastic scattering of other weakly and tightly bound projectiles on C12, as a function of energy. With the exception of He4 and O16, the data can be described using a universal function for the reduced cross sections.

  3. Activation cross sections of deuteron induced reactions on niobium in the 30-50 MeV energy range

    NASA Astrophysics Data System (ADS)

    Ditrói, F.; Tárkányi, F.; Takács, S.; Hermanne, A.; Ignatyuk, A. V.

    2016-04-01

    Activation cross-sections of deuterons induced reactions on Nb targets were determined with the aim of different applications and comparison with theoretical models. We present the experimental excitation functions of 93Nb(d,x)93m,90Mo, 92m,91m,90Nb, 89,88Zr and 88,87m,87gY in the energy range of 30-50 MeV. The results were compared with earlier measurements and with the cross-sections calculated by means of the theoretical model codes ALICE-D, EMPIRE-D and TALYS (on-line TENDL-2014 and TENDL-2015 libraries). Possible applications of the radioisotopes are discussed in detail.

  4. How the projectile neutron number influences the evaporation cross section in complete fusion reactions with heavy ions

    SciTech Connect

    Wang Chengbin; Zhang Jinjuan; Ren, Z. Z.; Shen, C. W.

    2010-11-15

    The influence of the projectile neutron number on the evaporation residue cross sections for the reactions {sup 208}Pb({sup 52,54}Cr,n,2n){sup 258-261}Sg and {sup 208}Pb({sup 48,50}Ti,n,2n){sup 254-257}Rf has been studied within the framework of a fusion-fission statistical model. The results obtained with the kewpie2 code are compared with recent experimental data. The excitation functions represent the experimental results well both in the maximum value and the lactation of the peak. The calculations show that the projectile neutron number greatly influences both the capture cross section and the fusion probability.

  5. Use of Neutron Transfer Reactions to Indirectly Determine Neutron Capture Cross Sections on Neutron-Rich Nuclei

    SciTech Connect

    McCleskey, M.; Mukhamedzhanov, A. M.; Tribble, R. E.; Simmons, E.; Spiridon, A.; Banu, A.; Roeder, B.; Goldberg, V.; Trache, L.; Chen, X. F.; Lui, Y.-W.

    2010-03-01

    {sup 14}C(n,gamma){sup 15}C is being used as a test case in the development of an indirect method to determine neutron capture cross sections on neutron-rich unstable nuclei at astrophysical energies. Our approach makes use of two reactions: one peripheral used to find the asymptotic normalization coefficient (ANC) and a second non-peripheral reaction to determine the spectroscopic factor. The ANC for {sup 15}C has been determined using a HI neutron transfer reaction with a 12 MeV/nucleon {sup 14}C beam on a {sup 13}C target. The spectroscopic factor will be determined using {sup 14}C(d,p) in forward kinematics with an incident deuteron energy of 60 MeV. Both experiments were performed using the MDM high-resolution spectrometer at Texas A and M University.

  6. Ionic Conduction in Lithium Ion Battery Composite Electrode Governs Cross-sectional Reaction Distribution

    PubMed Central

    Orikasa, Yuki; Gogyo, Yuma; Yamashige, Hisao; Katayama, Misaki; Chen, Kezheng; Mori, Takuya; Yamamoto, Kentaro; Masese, Titus; Inada, Yasuhiro; Ohta, Toshiaki; Siroma, Zyun; Kato, Shiro; Kinoshita, Hajime; Arai, Hajime; Ogumi, Zempachi; Uchimoto, Yoshiharu

    2016-01-01

    Composite electrodes containing active materials, carbon and binder are widely used in lithium-ion batteries. Since the electrode reaction occurs preferentially in regions with lower resistance, reaction distribution can be happened within composite electrodes. We investigate the relationship between the reaction distribution with depth direction and electronic/ionic conductivity in composite electrodes with changing electrode porosities. Two dimensional X-ray absorption spectroscopy shows that the reaction distribution is happened in lower porosity electrodes. Our developed 6-probe method can measure electronic/ionic conductivity in composite electrodes. The ionic conductivity is decreased for lower porosity electrodes, which governs the reaction distribution of composite electrodes and their performances. PMID:27193448

  7. Ionic Conduction in Lithium Ion Battery Composite Electrode Governs Cross-sectional Reaction Distribution

    NASA Astrophysics Data System (ADS)

    Orikasa, Yuki; Gogyo, Yuma; Yamashige, Hisao; Katayama, Misaki; Chen, Kezheng; Mori, Takuya; Yamamoto, Kentaro; Masese, Titus; Inada, Yasuhiro; Ohta, Toshiaki; Siroma, Zyun; Kato, Shiro; Kinoshita, Hajime; Arai, Hajime; Ogumi, Zempachi; Uchimoto, Yoshiharu

    2016-05-01

    Composite electrodes containing active materials, carbon and binder are widely used in lithium-ion batteries. Since the electrode reaction occurs preferentially in regions with lower resistance, reaction distribution can be happened within composite electrodes. We investigate the relationship between the reaction distribution with depth direction and electronic/ionic conductivity in composite electrodes with changing electrode porosities. Two dimensional X-ray absorption spectroscopy shows that the reaction distribution is happened in lower porosity electrodes. Our developed 6-probe method can measure electronic/ionic conductivity in composite electrodes. The ionic conductivity is decreased for lower porosity electrodes, which governs the reaction distribution of composite electrodes and their performances.

  8. Ionic Conduction in Lithium Ion Battery Composite Electrode Governs Cross-sectional Reaction Distribution.

    PubMed

    Orikasa, Yuki; Gogyo, Yuma; Yamashige, Hisao; Katayama, Misaki; Chen, Kezheng; Mori, Takuya; Yamamoto, Kentaro; Masese, Titus; Inada, Yasuhiro; Ohta, Toshiaki; Siroma, Zyun; Kato, Shiro; Kinoshita, Hajime; Arai, Hajime; Ogumi, Zempachi; Uchimoto, Yoshiharu

    2016-01-01

    Composite electrodes containing active materials, carbon and binder are widely used in lithium-ion batteries. Since the electrode reaction occurs preferentially in regions with lower resistance, reaction distribution can be happened within composite electrodes. We investigate the relationship between the reaction distribution with depth direction and electronic/ionic conductivity in composite electrodes with changing electrode porosities. Two dimensional X-ray absorption spectroscopy shows that the reaction distribution is happened in lower porosity electrodes. Our developed 6-probe method can measure electronic/ionic conductivity in composite electrodes. The ionic conductivity is decreased for lower porosity electrodes, which governs the reaction distribution of composite electrodes and their performances. PMID:27193448

  9. An efficient nonclassical quadrature for the calculation of nonresonant nuclear fusion reaction rate coefficients from cross section data

    NASA Astrophysics Data System (ADS)

    Shizgal, Bernie D.

    2016-08-01

    Nonclassical quadratures based on a new set of half-range polynomials, Tn(x) , orthogonal with respect to w(x) =e - x - b /√{ x } for x ∈ [ 0 , ∞) are employed in the efficient calculation of the nuclear fusion reaction rate coefficients from cross section data. The parameter b = B /√{kB T } in the weight function is temperature dependent and B is the Gamow factor. The polynomials Tn(x) satisfy a three term recurrence relation defined by two sets of recurrence coefficients, αn and βn. These recurrence coefficients define in turn the tridiagonal Jacobi matrix whose eigenvalues are the quadrature points and the weights are calculated from the first components of the eigenfunctions. For nonresonant nuclear reactions for which the astrophysical function can be expressed as a lower order polynomial in the relative energy, the convergence of the thermal average of the reactive cross section with this nonclassical quadrature is extremely rapid requiring in many cases 2-4 quadrature points. The results are compared with other libraries of nuclear reaction rate coefficient data reported in the literature.

  10. Cross section systematics for the lightest Bi and Po nuclei produced in complete fusion reactions with heavy ions

    SciTech Connect

    Andreyev, A.N.; Ackermann, D.; Muenzenberg, G.; Antalic, S.; Saro, S.; Streicher, B.; Darby, I.G.; Page, R.D.; Wiseman, D.R.; Franchoo, S.; Hessberger, F.P.; Kuusiniemi, P.; Lommel, B.; Kindler, B.; Mann, R.; Sulignano, B.; Hofmann, S.; Huyse, M.; Vel, K. van de; Duppen, P. van

    2005-07-01

    The production of the very neutron-deficient nuclides {sup 184-192}Bi and {sup 186-192}Po in the vicinity of the neutron midshell at N = 104 has been studied by using heavy-ion-induced complete fusion reactions in a series of experiments at the velocity filter SHIP. The cross sections for the xn and pxn evaporation channels of the {sup 46}Ti+{sup 144}Sm{yields}{sup 190}Po*,{sup 98}Mo+{sup 92}Mo{yields}{sup 190}Po*,{sup 50,52}Cr+{sup 142}Nd{yields}{sup 192,194}Po*, and {sup 94,95}Mo+{sup 93}Nb{yields}{sup 187,188}Bi* reactions were measured. The results obtained, together with the previously known cross section data for the heavier Bi and Po nuclides, are compared with the results of statistical model calculations carried out with the HIVAP code. It is shown that a satisfactory description of the experimental data requires a significant (up to 35%) reduction of the theoretical fission barriers. The optimal reactions for production of the lightest Bi and Po isotopes are discussed.

  11. Ground-State Properties of Mg Isotopes in and Beyond the Island of Inversion through Reaction Cross Sections

    NASA Astrophysics Data System (ADS)

    Watanabe, Shin; Minomo, Kosho; Shimada, Mitsuhiro; Tagami, Shingo; Kimura, Masaaki; Takechi, Maya; Fukuda, Mitsunori; Nishimura, Daiki; Suzuki, Takeshi; Matsumoto, Takuma; Shimizu, Yoshifumi R.; Yahiro, Masanobu

    We analyze recently measured total reaction cross sections (σR) for 24-38Mg incident on 12C targets at 240 MeV/nucleon by using the microscopic framework based on the double folding model and antisymmetrized molecular dynamics (AMD). The framework reproduces not only the measured σR but also other existing measured ground-state properties of Mg Isotopes (spin parity, total binding energy, one-neutron separation energy, and 2+ and 4+ excitation energies) quite well. AMD predicts large deformation from 31Mg19 to a drip-line nucleus 40Mg28, indicating that both the N = 20 and 28 magicities disappear.

  12. Differential cross sections for the reactions gamma p-> p eta and gamma p -> p eta-prime

    SciTech Connect

    M. Williams, Z. Krahn, D. Applegate, M. Bellis, C.A. Meyer, for the CLAS Collaboration

    2009-10-01

    High-statistics differential cross sections for the reactions gamma p -> p eta and gamma p -> p eta-prime have been measured using the CLAS at Jefferson Lab for center-of-mass energies from near threshold up to 2.84 GeV. The eta-prime results are the most precise to date and provide the largest energy and angular coverage. The eta measurements extend the energy range of the world's large-angle results by approximately 300 MeV. These new data, in particular the eta-prime measurements, are likely to help constrain the analyses being performed to search for new baryon resonance states.

  13. New data on activation cross section for deuteron induced reactions on ytterbium up to 50 MeV

    NASA Astrophysics Data System (ADS)

    Tárkányi, F.; Ditrói, F.; Takács, S.; Hermanne, A.; Ignatyuk, A. V.

    2014-10-01

    Activation cross sections of deuteron induced reactions on ytterbium for production of 177g,173,172,171,170,169,167Lu, 177,175,169Yb and 173,168,167,165Tm were extended up to 50 MeV deuteron energy. The new data are in acceptable agreement with the earlier experimental data in the overlapping energy region. The experimental data are compared with the predictions of the ALICE-D, EMPIRE-D and TALYS 1.4 (TENDL-2013 on-line library results) codes.

  14. Differential cross sections for the reactions γp→pη and γp→pη'

    DOE PAGESBeta

    Williams, M.; Krahn, Z.; Applegate, D.; Bellis, M.; Meyer, C. A.; Adhikari, K. P.; Anghinolfi, M.; Baghdasaryan, H.; Ball, J.; Battaglieri, M.; et al

    2009-10-29

    In high-statistics differential cross sections for the reactions γ p -> p η and γ p -> p η' the CLAS at Jefferson Lab was used to measure the center-of-mass energies from near threshold up to 2.84 GeV. The eta-prime results are the most precise to date and provide the largest energy and angular coverage. The eta measurements extend the energy range of the world's large-angle results by approximately 300 MeV. These new data, in particular the η' measurements, are likely to help constrain the analyses being performed to search for new baryon resonance states.

  15. Fusion cross sections for the {sup 9}Be+{sup 124}Sn reaction at energies near the Coulomb barrier

    SciTech Connect

    Parkar, V. V.; Palit, R.; Sharma, Sushil K.; Naidu, B. S.; Santra, S.; Mahata, K.; Ramachandran, K.; Joshi, P. K.; Rath, P. K.; Trivedi, T.; Raghav, A.

    2010-11-15

    The complete and incomplete fusion cross sections for {sup 9}Be+{sup 124}Sn reaction have been deduced using the online {gamma}-ray measurement technique. Complete fusion at energies above the Coulomb barrier was found to be suppressed by {approx}28% compared to the coupled-channels calculations and is in agreement with the systematics of L. R. Gasques et al. [Phys. Rev. C 79, 034605 (2009)]. Study of the projectile dependence for fusion on a {sup 124}Sn target shows that, for {sup 9}Be nuclei, the enhancement at below-barrier energies is substantial compared to that of tightly bound nuclei.

  16. Differential cross sections for the reactions γp→pη and γp→pη'

    NASA Astrophysics Data System (ADS)

    Williams, M.; Krahn, Z.; Applegate, D.; Bellis, M.; Meyer, C. A.; Adhikari, K. P.; Anghinolfi, M.; Baghdasaryan, H.; Ball, J.; Battaglieri, M.; Bedlinskiy, I.; Berman, B. L.; Biselli, A. S.; Bookwalter, C.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Careccia, S. L.; Carman, D. S.; Cole, P. L.; Collins, P.; Crede, V.; D'Angelo, A.; Daniel, A.; Vita, R. De; Sanctis, E. De; Deur, A.; Dey, B.; Dhamija, S.; Dickson, R.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dugger, M.; Dupre, R.; Alaoui, A. El; Elouadrhiri, L.; Eugenio, P.; Fegan, S.; Fradi, A.; Gabrielyan, M. Y.; Garçon, M.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Hassall, N.; Hicks, K.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jawalkar, S. S.; Jo, H. S.; Johnstone, J. R.; Joo, K.; Keller, D.; Khandaker, M.; Khetarpal, P.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Kuleshov, S. V.; Kuznetsov, V.; Livingston, K.; Lu, H. Y.; Mayer, M.; McAndrew, J.; McCracken, M. E.; McKinnon, B.; Mikhailov, K.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Moriya, K.; Morrison, B.; Munevar, E.; Nadel-Turonski, P.; Nepali, C. S.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niroula, M. R.; Niyazov, R. A.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Park, S.; Pasyuk, E.; Pereira, S. Anefalos; Perrin, Y.; Pieschacon, D.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salamanca, J.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seraydaryan, H.; Sharabian, Y. G.; Smith, E. S.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tedeschi, D. J.; Tkachenko, S.; Ungaro, M.; Vineyard, M. F.; Voutier, E.; Watts, D. P.; Weinstein, L. B.; Weygand, D. P.; Wood, M. H.; Zhang, J.; Zhao, B.

    2009-10-01

    High-statistics differential cross sections for the reactions γp→pη and γp→pη' have been measured using the CEBAF large acceptance spectrometer (CLAS) at Jefferson Lab for center-of-mass energies from near threshold up to 2.84 GeV. The η' results are the most precise to date and provide the largest energy and angular coverage. The η measurements extend the energy range of the world’s large-angle results by approximately 300 MeV. These new data, in particular the η' measurements, are likely to help constrain the analyses being performed to search for new baryon resonance states.

  17. Measurement of evaporation residue cross-sections of the reaction 30Si + 238U at subbarrier energies

    SciTech Connect

    Nishio, K.; Ikezoe, H.; Mitsuoka, S.; Nagame, Y.; Tsukada, K.; Tsuruta, K.; Hofmann, S.; Hessberger, F. P.; Ackermann, D.; Heinz, S.; Khuyagbaatar, J.; Kindler, B.; Kojouharov, I.; Lommel, B.; Mazzocco, M.; Schoett, H. J.; Antalic, S.; Saro, S.; Comas, V. F.; Heredia, J. A.

    2007-02-26

    The reaction 30Si + 238U {yields} 268Sg* was studied at beam energies close to the Coulomb barrier. At the above barrier energy of Ec.m. = 144.0 MeV (center-of-mass energy at half thickness of the target), we measured three decay chains of 263Sg produced by evaporation of five neutrons. The cross-section was (67{sub -37}{sup +67}) pb. At subbarrier energy of Ec.m. = 133.0 MeV we measured three spontaneously fissioning nuclei which we assigned to the isotope 264Sg. The half-life of (120{sub -44}{sup +126}) ms was determined. The production cross-section was (10{sub -6}{sup +10}) pb, which is about four orders magnitude larger than the calculation based on the one-dimensional barrier penetration model in the fusion process, showing fusion enhancement caused by the prolate deformation of 238U. At Ec.m. = 128.0 MeV an upper cross-section limit of 15 pb was measured. Compared to excitation functions measured for the lighter system 16O + 238U {yields} 254Fm*, a reduction of the fusion probability was observed at low beam energies indicating increasing competition from quasifission processes.

  18. Partial cross sections of the 92Mo(p ,γ ) reaction and the γ strength in 93Tc

    NASA Astrophysics Data System (ADS)

    Mayer, J.; Goriely, S.; Netterdon, L.; Péru, S.; Scholz, P.; Schwengner, R.; Zilges, A.

    2016-04-01

    Background: 92Mo is the most abundant nucleus of the p nuclei, with an isotopic abundance of more than 14 %. The γ -process nucleosynthesis is believed to produce 92Mo but fails to explain its large abundance, especially with respect to the other p nuclei produced in the same stellar environment. Further studies require precise nuclear models for the calculation of reaction cross sections. Purpose: A measurement of the total and partial cross sections of the 92Mo(p ,γ )93Tc reaction allows for a stringent test of statistical-model predictions. Not only different proton+nucleus optical model potentials, but also the γ -ray strength function of 93Tc can be investigated. In addition, high-resolution in-beam γ -ray spectroscopy enables the determination of new precise nuclear structure data for 93Tc. Method: Total and partial cross-section values were measured by using the in-beam method. Prompt γ rays emitted during the irradiation of 92Mo with protons at seven different energies between 3.7 and 5.3 MeV were detected by using the high-purity germanium (HPGe) detector array HORUS at the Institute for Nuclear Physics, University of Cologne. The γ γ -coincidence method was applied to correlate γ -ray cascades in 93Tc with their origin in the 92Mo+p compound state. Results: The measured cross sections are compared to Hauser-Feshbach calculations by using the statistical-model code talys on the basis of different nuclear physics input models. Using default settings based on standard phenomenological models, the experimental values cannot be reproduced. A shell-model calculation was carried out to predict the low-energy M 1 strength in 93Tc. Together with Gogny-Hartree-Fock-Bogoliubov (Gogny-HFB) or Skyrme-HFB plus quasi-particle random-phase approximation (QRPA) models for the γ -ray strength function, the agreement between experimental data and theoretical predictions could be significantly improved. In addition, deviations from the adopted level scheme were

  19. Evaporation residue cross sections for the {sup 100}Mo + {sup 116}Cd reaction -- energy dissipation in hot nuclei

    SciTech Connect

    Back, B.B.; Blumenthal, D.J.; Davids, C.N.

    1995-08-01

    In this experiment we tried to measure the evaporation residue cross section over a wide range of beam energies for the {sup 100}Mo + {sup 116}Cd reaction using the FMA. However, because of longer-than-estimated runs needed at each beam energy, and the difficulty of bending evaporation residues at the higher energies in the FMA, data were taken only at beam energies of E{sub beam} = 460, 490, and 521 MeV, which correspond to excitation energies of E{sub exc} = 62, 78, and 95 MeV, respectively. By comparing to results for the {sup 32}S + {sup 184}W reactions measured recently, we expect to demonstrate a strong entrance channel effect related to the hindrance of complete fusion in near-symmetric heavy systems (a fusion hindrance factor of the order 7-10 is expected on the basis of the Extra-Push Model). The data are being analyzed.

  20. Elastic scattering and total reaction cross section for the {sup 6}He+{sup 58}Ni system

    SciTech Connect

    Morcelle, V.; Lichtenthäler, R.; Lépine-Szily, A.; Guimarães, V.; Gasques, L.; Scarduelli, V.; Condori, R. Pampa; Leistenschneider, E.; Mendes Jr, D. R.; Faria, P. N. de; Pires, K. C. C.; Barioni, A.; Morais, M. C.; Shorto, J. M. B.; Zamora, J. C.

    2014-11-11

    Elastic scattering measurements of {sup 6}He + {sup 58}Ni system have been performed at the laboratory energy of 21.7 MeV. The {sup 6}He secondary beam was produced by a transfer reaction {sup 9}Be ({sup 7}Li, {sup 6}He) and impinged on {sup 58}Ni and {sup 197}Au targets, using the Radioactive Ion Beam (RIB) facility, RIBRAS, installed in the Pelletron Laboratory of the Institute of Physics of the University of São Paulo, Brazil. The elastic angular distribution was obtained in the angular range from 15° to 80° in the center of mass frame. Optical model calculations have been performed using a hybrid potential to fit the experimental data. The total reaction cross section was derived.

  1. Jet inclusive cross sections

    SciTech Connect

    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.

  2. Energy-loss cross sections for inclusive charge-exchange reactions at intermediate energies

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Townsend, Lawrence W.; Dubey, Rajendra R.

    1993-01-01

    Charge-exchange reactions for scattering to the continuum are considered in a high-energy multiple scattering model. Calculations for (p,n) and (He-3,H-3) reactions are made and compared with experimental results for C-12, O-16, and Al-27 targets. Coherent effects are shown to lead to an important role for inelastic multiple scattering terms when light projectiles are considered.

  3. Photo-neutron cross-section calculations of 142,143,144,145,146,150Nd rare-earth isotopes for ( γ, n) reaction

    NASA Astrophysics Data System (ADS)

    Kaplan, A.; Özdoğan, H.; Aydin, A.; Tel, E.

    2014-11-01

    The theoretical photo-neutron cross sections for ( γ, n) reaction have been calculated on 142,143,144,145,146,150Nd rare-earth isotopes at photon energies of 8-23 MeV using the PCROSS, TALYS 1.2, and EMPIRE 3.1 computer codes. TALYS 1.2 two-component exciton model and EMPIRE 3.1 exciton model has been used to calculate the pre-equilibrium photo-neutron cross sections. PCROSS Weisskopf-Ewing model has been used for the reaction equilibrium cross-section calculations. The obtained cross sections have been compared with each other and against the experimental values existing in the EXFOR database. Generally, pre-equilibrium model cross-section calculations are in good agreement with the experimental data for all reactions along the incident photon energy in this study.

  4. Reexamination of cross sections of the 100Mo(p,2n)99mTc reaction

    NASA Astrophysics Data System (ADS)

    Takács, S.; Hermanne, A.; Ditrói, F.; Tárkányi, F.; Aikawa, M.

    2015-03-01

    The nuclear medicine community has been expressing concerns world wide regarding shortages of 99mTc supply based on fission production of 99Mo from highly enriched uranium (HEU) to prepare 99Mo/99mTc generators. As an alternative to reactor produced 99Mo/99mTc generator technology, the direct production of 99mTc on accelerators is considered. There are a number of methods of using accelerators to produce 99mTc and/or 99Mo. Direct production of 99mTc on highly enriched 100Mo target using cyclotrons is interesting for energies up to 20 MeV, so as to minimize the impurities from additional open reaction channels. To estimate the quality of the accelerator produced 99mTc all the possible reaction routes should be mapped which could be potentially involved in this technology. However, a well defined excitation function for the 100Mo(p,2n)99mTc primary reaction is needed, in order to achieve acceptable good results in assessing the quality of the accelerator-produced 99mTc by theoretical calculations. Most of the available experimental cross section data series for the 100Mo(p,2n)99mTc reaction have the same general shape while their amplitudes are different. A large difference more than a factor of two may, indeed, be observed between the lowest and the highest datasets values. The aim of this study was therefore to get a new evaluation for the 100Mo(p,2n)99mTc cross section, through three independent experiments, aiming at a more confident estimation about the amplitude of the excitation function.

  5. Experimental differential cross sections, level densities, and spin cutoffs as a testing ground for nuclear reaction codes

    SciTech Connect

    Voinov, Alexander V.; Grimes, Steven M.; Brune, Carl R.; Burger, Alexander; Gorgen, Andreas; Guttormsen, Magne; Larsen, Ann -Cecilie; Massey, Thomas N.; Siem, Sunniva

    2013-11-08

    Proton double-differential cross sections from 59Co(α,p)62Ni, 57Fe(α,p)60Co, 56Fe(7Li,p)62Ni, and 55Mn(6Li,p)60Co reactions have been measured with 21-MeV α and 15-MeV lithium beams. Cross sections have been compared against calculations with the empire reaction code. Different input level density models have been tested. It was found that the Gilbert and Cameron [A. Gilbert and A. G. W. Cameron, Can. J. Phys. 43, 1446 (1965)] level density model is best to reproduce experimental data. Level densities and spin cutoff parameters for 62Ni and 60Co above the excitation energy range of discrete levels (in continuum) have been obtained with a Monte Carlo technique. Furthermore, excitation energy dependencies were found to be inconsistent with the Fermi-gas model.

  6. Partial gamma-ray cross section measurements in 109Ag(n, x n y p gamma) reactions

    SciTech Connect

    Fotiadis, Nikolaos; Devlin, Matthew James; Nelson, Ronald Owen; Carroll, James

    2015-06-02

    We report on absolute partial cross sections for production of discrete γ-rays using 109Ag(n, xnypγ) reactions with x ≤ 7 and y ≤ 1 in a total of 12 reaction channels. The data were taken using the GEANIE spectrometer comprised of 20 high-purity Ge detectors with 20 BGO escape-suppression shields. The broad-spectrum pulsed neutron beam of the Los Alamos Neutron Science Center’s (LANSCE) WNR facility provided neutrons in the energy range from 0.2 to 300 MeV. The time-of- flight technique was used to determine the incident neutron energies. Partial γ-ray cross sections have been measured for a total of 109 transitions and for neutron energies 0.8 MeV< En<300 MeV. An estimate of the population of isomers in the (n, n'), (n, 2n) and (n, 3n) channels was made.

  7. Comparison of 3D Classical Trajectory and Transition-State Theory Reaction Cross Sections

    DOE R&D Accomplishments Database

    Koeppl, G. W.; Karplus, Martin

    1970-10-01

    Although there is excellent agreement for a system such as H+H{sub 2} --> H{sub 2}+H, in which both the potential and the particle masses are symmetric, significant deviations occur for more asymmetric reactions. A detailed analysis show that the calculated differences are from the violation of two assumptions of transition-state theory.

  8. Optimization of the Efficiency of a Neutron Detector to Measure (α, n) Reaction Cross-Section

    NASA Astrophysics Data System (ADS)

    Perello, Jesus; Montes, Fernando; Ahn, Tony; Meisel, Zach; Joint InstituteNuclear Astrophysics Team

    2015-04-01

    Nucleosynthesis, the origin of elements, is one of the greatest mysteries in physics. A recent particular nucleosynthesis process of interest is the charge-particle process (cpp). In the cpp, elements form by nuclear fusion reactions during supernovae. This process of nuclear fusion, (α,n), will be studied by colliding beam elements produced and accelerated at the National Superconducting Cyclotron Laboratory (NSCL) to a helium-filled cell target. The elements will fuse with α (helium nuclei) and emit neutrons during the reaction. The neutrons will be detected for a count of fused-elements, thus providing us the probability of such reactions. The neutrons will be detected using the Neutron Emission Ratio Observer (NERO). Currently, NERO's efficiency varies for neutrons at the expected energy range (0-12 MeV). To study (α,n), NERO's efficiency must be near-constant at these energies. Monte-Carlo N-Particle Transport Code (MCNP6), a software package that simulates nuclear processes, was used to optimize NERO configuration for the experiment. MCNP6 was used to simulate neutron interaction with different NERO configurations at the expected neutron energies. By adding additional 3He detectors and polyethylene, a near-constant efficiency at these energies was obtained in the simulations. With the new NERO configuration, study of the (α,n) reactions can begin, which may explain how elements are formed in the cpp. SROP MSU, NSF, JINA, McNair Society.

  9. Au, Bi, Co and Nb cross-section measured by quasimonoenergetic neutrons from p + 7Li reaction in the energy range of 18-36 MeV

    NASA Astrophysics Data System (ADS)

    Majerle, M.; Bém, P.; Novák, J.; Šimečková, E.; Štefánik, M.

    2016-09-01

    Au, Bi, Co and Nb samples were irradiated several times with quasi-monoenergetic neutrons from p + 7Li reaction in the energy range of 18-36 MeV. The activities of the samples were measured with the HPGe detector and the reaction rates were calculated. The cross-sections were extracted using the SAND-II method with the reference cross-sections from the EAF-2010 database. The uncertainties of the final results are discussed.

  10. State-resolved differential and integral cross sections for the Ne + H2+ (v = 0-2, j = 0) → NeH+ + H reaction

    NASA Astrophysics Data System (ADS)

    Wu, Hui; Yao, Cui-Xia; He, Xiao-Hu; Zhang, Pei-Yu

    2016-05-01

    State-to-state quantum dynamic calculations for the proton transfer reaction Ne + H2+ (v = 0-2, j = 0) are performed on the most accurate LZHH potential energy surface, with the product Jacobi coordinate based time-dependent wave packet method including the Coriolis coupling. The J = 0 reaction probabilities for the title reaction agree well with previous results in a wide range of collision energy of 0.2-1.2 eV. Total integral cross sections are in reasonable agreement with the available experiment data. Vibrational excitation of the reactant is much more efficient in enhancing the reaction cross sections than translational and rotational excitation. Total differential cross sections are found to be forward-backward peaked with strong oscillations, which is the indication of the complex-forming mechanism. As the collision energy increases, state-resolved differential cross section changes from forward-backward symmetric peaked to forward scattering biased. This forward bias can be attributed to the larger J partial waves, which makes the reaction like an abstraction process. Differential cross sections summed over two different sets of J partial waves for the v = 0 reaction at the collision energy of 1.2 eV are plotted to illustrate the importance of large J partial waves in the forward bias of the differential cross sections.

  11. State-resolved differential and integral cross sections for the Ne + H2 (+) (v = 0-2, j = 0) → NeH(+) + H reaction.

    PubMed

    Wu, Hui; Yao, Cui-Xia; He, Xiao-Hu; Zhang, Pei-Yu

    2016-05-14

    State-to-state quantum dynamic calculations for the proton transfer reaction Ne + H2 (+) (v = 0-2, j = 0) are performed on the most accurate LZHH potential energy surface, with the product Jacobi coordinate based time-dependent wave packet method including the Coriolis coupling. The J = 0 reaction probabilities for the title reaction agree well with previous results in a wide range of collision energy of 0.2-1.2 eV. Total integral cross sections are in reasonable agreement with the available experiment data. Vibrational excitation of the reactant is much more efficient in enhancing the reaction cross sections than translational and rotational excitation. Total differential cross sections are found to be forward-backward peaked with strong oscillations, which is the indication of the complex-forming mechanism. As the collision energy increases, state-resolved differential cross section changes from forward-backward symmetric peaked to forward scattering biased. This forward bias can be attributed to the larger J partial waves, which makes the reaction like an abstraction process. Differential cross sections summed over two different sets of J partial waves for the v = 0 reaction at the collision energy of 1.2 eV are plotted to illustrate the importance of large J partial waves in the forward bias of the differential cross sections. PMID:27179478

  12. Investigation of the effects of nuclear level density parameters on the cross sections for the 234U(γ,f) reaction

    NASA Astrophysics Data System (ADS)

    Pekdogan, Hakan; Aydin, Abdullah; Hakki Sarpun, Ismail

    2015-07-01

    In this study, we have investigated the effects of nuclear level density parameters on the cross sections for the 234U(γ,f) reaction up to 20 MeV. The cross sections on 234U(γ,f) reaction were calculated for different level density models using the TALYS 1.6 code. First, it was determined the level density model that was the closest to the experimental data. Secondly, cross sections obtained for different level density parameters of this model were compared with experimental data from the EXFOR database. Thus it was determined the best level density parameter fit to experimental data.

  13. Cross-Section Measurements for Proton- and Neutron-Induced Reactions Needed to Understand Cosmic-Ray Interactions on Earth and in Space

    NASA Astrophysics Data System (ADS)

    Sisterson, Janet M.

    2005-05-01

    Primary cosmic rays interact directly with extraterrestrial bodies and cosmic-ray shower particles interact with the earth's surface to produce small quantities of radionuclides and stable isotopes, which are measured routinely using appropriate techniques. Theoretical models are used to analyze these measurements to learn the history of the object or the cosmic rays that fell upon it. Cross sections for reactions producing these cosmogenic nuclides are essential input to these models. Most primary cosmic rays are protons, and good measurements of the cross sections for proton-induced reactions are essential. Most relevant cross sections are now well measured, but discrepancies still exist between the measurements and calculations. One explanation is that neutrons produced in primary cosmic-ray interactions also initiate spallation reactions contributing significantly to the cosmogenic nuclide inventory, but few of the relevant cross sections have been measured at energies >30 MeV. We have measured many of these needed cross sections for neutron-induced reactions using two different techniques. Cross sections at selected unique neutron energies >70 MeV are measured at iThemba LABS, South Africa (iTL) using quasi-monoenergetic neutron beams. Energy integrated (average) cross sections are measured at the Los Alamos Neutron Science Center (LANSCE), using `white' neutron beams with an energy range of 0.1-750 MeV.

  14. Differential cross section and recoil polarization measurements for the gamma p to K+ Lambda reaction using CLAS at Jefferson Lab

    SciTech Connect

    McCracken, Michael E.

    2010-02-01

    We present measurements of the differential cross section and Lambda recoil polarization for the gamma p to K+ Lambda reaction made using the CLAS detector at Jefferson Lab. These measurements cover the center-of-mass energy range from 1.62 to 2.84 GeV and a wide range of center-of-mass K+ production angles. Independent analyses were performed using the K+ p pi- and K+ p (missing pi -) final-state topologies; results from these analyses were found to exhibit good agreement. These differential cross section measurements show excellent agreement with previous CLAS and LEPS results and offer increased precision and a 300 MeV increase in energy coverage. The recoil polarization data agree well with previous results and offer a large increase in precision and a 500 MeV extension in energy range. The increased center-of-mass energy range that these data represent will allow for independent study of non-resonant K+ Lambda photoproduction mechanisms at all production angles.

  15. Differential cross section and recoil polarization measurements for the γp→K+Λ reaction using CLAS at Jefferson Lab

    NASA Astrophysics Data System (ADS)

    McCracken, M. E.; Bellis, M.; Meyer, C. A.; Williams, M.; Adhikari, K. P.; Anghinolfi, M.; Ball, J.; Battaglieri, M.; Berman, B. L.; Biselli, A. S.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Careccia, S. L.; Carman, D. S.; Cole, P. L.; Collins, P.; Crede, V.; D'Angelo, A.; Daniel, A.; Dashyan, N.; de Vita, R.; de Sanctis, E.; Deur, A.; Dey, B.; Dhamija, S.; Dickson, R.; Djalali, C.; Doughty, D.; Dugger, M.; Dupre, R.; El Alaoui, A.; Eugenio, P.; Fegan, S.; Fradi, A.; Gabrielyan, M. Y.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Hafidi, K.; Hakobyanm, H.; Hanretty, C.; Hassall, N.; Hicks, K.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Jo, H. S.; Keller, D.; Khandaker, M.; Khetarpal, P.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Kuleshov, S. V.; Kuznetsov, V.; Livingston, K.; Mayer, M.; McAndrew, J.; McKinnon, B.; Mestayer, M. D.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Moreno, B.; Moriya, K.; Morrison, B.; Moutarde, H.; Munevar, E.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Park, S.; Pasyuk, E.; Pereira, S. Anefalos; Perrin, Y.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Prok, Y.; Protopopescu, D.; Quinn, B.; Raue, B. A.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salamanca, J.; Schott, D.; Schumacher, R. A.; Seder, E.; Seraydaryan, H.; Sharabian, Y. G.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stoler, P.; Strauch, S.; Taiuti, M.; Tedeschi, D. J.; Tkachenko, S.; Ungaro, M.; Vernarsky, B.; Vineyard, M. F.; Watts, D.; Voutier, E.; Weinstein, L. B.; Weygand, D. P.; Wood, M. H.; Zana, L.

    2010-02-01

    We present measurements of the differential cross section and Λ recoil polarization for the γp→K+Λ reaction made using the CLAS detector at Jefferson Lab. These measurements cover the center-of-mass energy range from 1.62 to 2.84 GeV and a wide range of center-of-mass K+ production angles. Independent analyses were performed using the K+pπ- and K+p (missing π-) final-state topologies; results from these analyses were found to exhibit good agreement. These differential-cross-section measurements show excellent agreement with previous CLAS and LEPS results and offer increased precision and a 300-MeV increase in energy coverage. The recoil polarization data agree well with previous results and offer a large increase in precision and a 500-MeV extension in energy range. The increased center-of-mass energy range that these data represent will allow for independent study of nonresonant K+Λ photoproduction mechanisms at all production angles.

  16. Evaporation residue cross sections for the {sup 64}Ni + {sup 144,154}Sm reaction -- Energy dissipation in hot nuclei

    SciTech Connect

    Back, B.B.; Blumenthal, D.J.; Davids, C.N.

    1995-08-01

    The fission hindrance of hot nuclei was deduced recently from an enhanced emission of GDR {gamma} rays, neutrons and charged particles prior to scission of heavy nuclei. In the most recent experiments addressing this topic, namely new measurements of the pre-scission {gamma} rays and evaporation residues from the {sup 32}S + {sup 184}W reaction, a rather sharp transition from negligible to full one-body dissipation occurs over the excitation energy region E{sub exc} = 60-100 MeV. However, the cross section does not appear to level out or start to decline again at the upper end of the energy range as expected in this interpretation. It is therefore clearly desirable to extend the excitation energy range to look for such an effect in order to either corroborate or refute this interpretation.

  17. Differential cross sections and spin density matrix elements for the reaction {gamma}p{yields}p{omega}

    SciTech Connect

    Williams, M.; Applegate, D.; Bellis, M.; Meyer, C. A.; Dey, B.; Dickson, R.; Krahn, Z.; McCracken, M. E.; Moriya, K.; Schumacher, R. A.; Adhikari, K. P.; Careccia, S. L.; Dodge, G. E.; Klein, A.; Mayer, M.; Nepali, C. S.; Niroula, M. R.; Seraydaryan, H.; Tkachenko, S.; Weinstein, L. B.

    2009-12-15

    High-statistics differential cross sections and spin-density matrix elements for the reaction {gamma}p{yields}p{omega} have been measured using the CEBAF large acceptance spectrometer (CLAS) at Jefferson Lab for center-of-mass (c.m.) energies from threshold up to 2.84 GeV. Results are reported in 112 10-MeV wide c.m. energy bins, each subdivided into cos{theta}{sub c.m.}{sup {omega}} bins of width 0.1. These are the most precise and extensive {omega} photoproduction measurements to date. A number of prominent structures are clearly present in the data. Many of these have not previously been observed due to limited statistics in earlier measurements.

  18. Activation cross-sections of proton induced reactions on vanadium in the 37-65 MeV energy range

    NASA Astrophysics Data System (ADS)

    Ditrói, F.; Tárkányi, F.; Takács, S.; Hermanne, A.

    2016-08-01

    Experimental excitation functions for proton induced reactions on natural vanadium in the 37-65 MeV energy range were measured with the activation method using a stacked foil irradiation technique. By using high resolution gamma spectrometry cross-section data for the production of 51,48Cr, 48V, 48,47,46,44m,44g,43Sc and 43,42K were determined. Comparisons with the earlier published data are presented and results predicted by different theoretical codes (EMPIRE and TALYS) are included. Thick target yields were calculated from a fit to our experimental excitation curves and compared with the earlier experimental yield data. Depth distribution curves to be used for thin layer activation (TLA) are also presented.

  19. Total and partial capture cross sections in reactions with deformed nuclei at energies near and below the Coulomb barrier

    SciTech Connect

    Kuzyakin, R. A. Sargsyan, V. V.; Adamian, G. G.; Antonenko, N. V.

    2013-06-15

    Within the quantum diffusion approach, the capture of a projectile nucleus by a target nucleus is studied at bombarding energies above and below the Coulomb barrier. The effects of deformation of interacting nuclei and neutron transfer between them on the total and partial capture cross sections and the mean angular momentum of the captured system are studied. The results obtained for the {sup 16}O + {sup 112}Cd, {sup 152}Sm, and {sup 184}W; {sup 19}F +{sup 175}Lu; {sup 28}Si +{sup 94,100}Mo and {sup 154}Sm; {sup 40}Ca +{sup 96}Zr; {sup 48}Ca+ {sup 90}Zr; and {sup 64}Ni +{sup 58,64}Ni, {sup 92,96}Zr, and {sup 100}Mo reactions are in good agreement with available experimental data.

  20. Total and partial capture cross sections in reactions with deformed nuclei at energies near and below the Coulomb barrier

    NASA Astrophysics Data System (ADS)

    Kuzyakin, R. A.; Sargsyan, V. V.; Adamian, G. G.; Antonenko, N. V.

    2013-06-01

    Within the quantum diffusion approach, the capture of a projectile nucleus by a target nucleus is studied at bombarding energies above and below the Coulomb barrier. The effects of deformation of interacting nuclei and neutron transfer between them on the total and partial capture cross sections and the mean angular momentum of the captured system are studied. The results obtained for the 16O + 112Cd, 152Sm, and 184W; 19F +175Lu; 28Si +94,100Mo and 154Sm; 40Ca +96Zr; 48Ca+ 90Zr; and 64Ni +58,64Ni, 92,96Zr, and 100Mo reactions are in good agreement with available experimental data.

  1. Low-energy cross sections in the {sup 12}C({alpha},{gamma}){sup 16}O reaction

    SciTech Connect

    Katsuma, M.

    2008-09-15

    The low-energy {sup 12}C({alpha},{gamma}){sup 16}O reaction is analyzed with the potential model. The potentials are chosen from the deep potential describing the {alpha}-particle nuclear rainbow phenomena at high energies. Below E{sub c.m.}=1 MeV, the cross section is found to be dominated by the E2 transition to the ground state of {sup 16}O. No enhancement of the E1 component at low energies is predicted. The extrapolated astrophysical S-factors at E{sub c.m.}=0.3 MeV are S{sub E2}=150 keV b and S{sub E1}=3 keV b.

  2. 89Y(γ,xn) reaction cross-section measurements with bremsstrahlung end-point energies of 50-65 MeV

    NASA Astrophysics Data System (ADS)

    Zaman, Muhammad; Kim, Guinyun; Kim, Kwangsoo; Shahid, Muhammad; Naik, Haladhara; Yang, Sungchul; Shin, Sung-Gyun; Cho, Moo-Hyun

    2015-10-01

    The cross-sections for 89Y(γ, n)88Y, 89Y(γ, 2n)87Y, 89Y(γ, 3n)86Y, and 89Y(γ, 4n)85Y reactions for the end-point bremsstrahlung energies of 50 and 65 MeV were determined by using an activation and an off-line γ-ray spectrometric techniques with the electron linear accelerator at the Pohang Accelerator laboratory (PAL), Korea. The photon-induced reaction cross-sections of 89Y as functions of the photon energy were taken from the TENDL-2013 nuclear data library based on the TALYS 1.6 program. For comparison with our experimental results, the flux-weighted average cross-sections for the existing experimental data with mono-energetic photons and the theoretical values from TENDL-2013 were obtained. The reaction cross-section values measured at different end-point bremsstrahlung energies from the present work and from literature are found to be in good agreement with the theoretical values. The 89Y(γ, xn, x = 1 - 4) reaction cross-sections were observed to increase sharply from their threshold values to certain energies, until the next reaction channel opens, after which it remained constant for a while until the next reaction channel opened. Then, it decrease slowly with increasing of end-point bremsstrahlung energy due to the opening of different reaction channels.

  3. Effects of projectile resonances on the total, Coulomb, and nuclear breakup cross sections in the 6Li+152Sm reaction

    NASA Astrophysics Data System (ADS)

    Mukeru, B.; Lekala, M. L.

    2016-08-01

    In this paper we analyze the effects of the projectile resonances on the total, Coulomb, and nuclear breakup cross sections as well as on the Coulomb-nuclear interferences at different arbitrary incident energies. It is found that these resonances have non-negligible effects on the total, Coulomb, and nuclear breakup cross sections. Qualitatively, they have no effects on the constructiveness or destructiveness of the Coulomb-nuclear interferences. Quantitatively, we obtained that these resonances increase by 7.38%, 7.58%, and 20.30% the integrated total, Coulomb, and nuclear breakup cross sections, respectively at Elab=35 MeV . This shows that the nuclear breakup cross sections are more affected by the effects of the projectile resonances than their total and Coulomb breakup counterparts. We also obtain that the effects of the resonances on the total, Coulomb, and nuclear breakup cross sections decrease as the incident energy increases.

  4. Measurement of the cross section for the reaction 20Ne( n,α)17O in the neutron-energy between 4 and 7 MeV

    NASA Astrophysics Data System (ADS)

    Khryachkov, V. A.; Bondarenko, I. P.; Kuzminov, B. D.; Semenova, N. N.; Sergachev, A. I.

    2012-04-01

    The cross section for the reaction 20Ne( n, α)17O was measured in the neutron-energy range 4-7 MeV. An ionization chamber equipped with a Frisch grid combined with a pulse-shape digitizer was used as a detector. Gaseous neon that served as a target on which the reaction being studied proceeded was added to the gas filling the ionization chamber. The partial cross sections for the α 0, α 1, α 2, and α 3 channels of the reaction 20Ne( n, α)17O were obtained for the first time.

  5. Novel 4π Detection System for the Measurement of the 6Li(n,α)3H Reaction Cross Section

    NASA Astrophysics Data System (ADS)

    Giorginis, Georgios; Bencardino, Raffaele

    2011-12-01

    A dedicated one-dimensional Time Projection Chamber (1D-TPC) was designed and produced at IRMM to determine the 6Li(n,α)3H cross section in the 0.4-2.8 MeV energy range, aiming at 5% accuracy. The basic TPC components were a twin gridded ionisation chamber (GIC) with interwired electrodes and fast digitisation of the anode and cathode signals. The energy of both reaction products emitted from a thin 6LiF sample at the common TPC cathode was measured. A Kr(97%)CO2(3%) mixture was used as the detector gas at a pressure up to 3.5 bar. A 238U sample mounted on the cathode of an ionisation chamber without grid was used as the neutron flux monitor. Special care was taken to reduce the experimental sources of uncertainty. The beam-monitor 238U sample was characterised at IRMM by low-geometry α-counting with an accuracy of 0.1%. A 6Li sample was produced at IRMM by vacuum evaporation of 6LiF onto transparent aluminium backing. The number of 6Li atoms will be measured via Thermal Neutron Depth Profiling with an expected accuracy of 2% with respect to an IRMM Standard Reference Material. First test measurements were performed using a monoenergetic neutron beam produced by the T(p,n)3He reaction at the IRMM 7 MV Van de Graaff accelerator. The experimental method and preliminary results are presented.

  6. Investigation of the pairing effect using newly evaluated empirical studies for 14-15 MeV neutron reaction cross sections

    SciTech Connect

    Tel, E.; Tanir, G.; Aydin, A.

    2007-03-15

    The asymmetry term effects for the cross sections of (n, charged particle) and (n,2n) reactions at 14-15 MeV neutron incident energy have been investigated. The effects of pairing and odd-even nucleon numbers in new data and in the formula of Tel et al. [J. Phys. G. 29, 2169 (2003)] are discussed. We have determined three different parameters groups by the classification of nuclei into even-even, even-odd, and odd-even (n,d) reactions. In addition, since there are not enough experimental data available, we have considered two different parameters groups by the classification of nuclei into odd-A and even-A (n,t) reaction cross sections. The empirical formulas with two parameters for the evaluation of the (n,d) and (n,t) reactions cross sections are discussed in the present study.

  7. Cross-section measurement for the 10B(n, alpha)7Li reaction at 4.0 and 5.0 MeV.

    PubMed

    Zhang, Guohui; Guo, Li'an; Cao, Rongtai; Zhang, Jiaguo; Chen, Jinxiang

    2008-10-01

    Cross-sections of the (10)B(n, alpha)(7)Li reaction were measured at En=4.0 and 5.0 MeV. A gridded ionization chamber (GIC) was used as charged particle detector. Neutrons were produced through the D(d, n)(3)He reaction with a deuterium gas target. Experiments were performed at the 4.5 MV Van de Graaff accelerator of Peking University. Cross-section data of the (238)U(n, f) reaction were employed as standard. The measured cross-sections of the (10)B(n, alpha)(7)Li reaction at 4.0 and 5.0 MeV are 211+/-17 and 169+/-14 mb, respectively, and they are compared with existing results of measurements and evaluations. PMID:18387305

  8. Self-reported sulphonamide hypersensitivity reactions in adults living in Ibadan, Nigeria: A cross-sectional, community-based study

    PubMed Central

    Mary, Akpan Richard; Olayinka, Kotila Adejoke; Onoja, Akpa Matthew; Olufunmilayo, Fawole; Adeyinka, Falusi Gladys; Chinedum, Babalola Peace

    2015-01-01

    Background: Documentation of adverse drug reactions (ADRs) is critical to a safe health delivery system. The aim of our study was to explore the prevalence of self-reported sulphonamide hypersensitivity reactions in a community-based sample of the general population in Ibadan, Nigeria. We also examined sociodemographic factors associated with ADRs in the sample. Patients and Methods: The study was cross-sectional in design with study sites in urban, semiurban, and rural settlement areas. Pretested questionnaires were administered on a one-on-one basis by trained interviewers. Frequency tables and percentages were computed for various levels of the variables. Chi-square test was used to assess the relationship between sulphonamide hypersensitivity and variables such as sociodemographic characteristics of respondents, respondents' knowledge of drugs, as well as drug sources. Variables found to be significantly associated with sulphonamide hypersensitivity were further investigated using multiple logistic regressions analysis. Results: Out of the 1062 respondents, 15.5% reported hypersensitivity to sulphonamides with skin reactions being the most prevalent. The proportion reporting ADRs was significantly higher among respondents with tertiary education (23.1%) than any other level of education (P = 0.008). In addition, individuals who were very knowledgeable about drug use (odds ratio[OR]: 2.07; 95% confidence interval [CI]: 1.15–3.73) and persons who got drugs from hospitals (OR: 2.00; 95% CI: 1.10–3.65) were more likely to report ADRs than those who were ignorant about drugs and those who purchased drugs from open markets, respectively. Conclusion: Prevalence of sulphonamide hypersensitivity is high among respondents, and ADRs is likely to be reported by people who are knowledgeable about drug use. PMID:26903698

  9. (n,2n) and (n,3n) cross sections of neutron-induced reactions on 150Sm for En from threshold to 35 MeV

    SciTech Connect

    Dashdorj, D; Mitchell, G; Kawano, T; Becker, J; Wu, C; Devlin, M; Fotiades, N; Nelson, R; Kunieda, S

    2009-03-16

    Cross-section measurements were made of prompt discrete {gamma}-ray production as a function of incident neutron energy (E{sub n} = 1 to 35 MeV) on a {sup 150}Sm sample fo 1550 mg/cm{sup 2} of Sm{sub 2}O{sub 3} enriched to 95.6% in {sup 150}Sm. Results are compared with enhanced Hauser-Feshbach model calculations including the pre-equilibrium reactions. Energetic neutrons were delivered by the Los Alamos Neutron Science Center facility. The prompt-reaction {gamma} rays were detected with the Compton-suppressed Germanium Array for Neutron Induced Excitations (GEANIE). Incident neutron energies were determined by the time-of-flight technique. Excitation functions for thirteen individual {gamma}-rays up to E{sub x} = 0.8 MeV in {sup 149}Sm and one {gamma}-ray transition between the first excited and ground state in {sup 148}Sm were measured. Partial {gamma}-ray cross sections were calculated using GNASH, an enhanced Hauser-Feshbach statistical nuclear reaction model code, and compared with the experimental results. The particle transmission coefficients were calculated with new systematic 'global' optical model potential parameters. The coupled-channel optical model based on the soft rotor model was employed to calculate the particle transmission coefficients. The pre-equilibrium part of the spin distribution in {sup 150}Sm was calculated using the quantum mechanical theory of Feshbach, Kerman, and Koonin (FKK) and incorporated into the GNASH reaction model code. the partial cross sections for discrete {gamma}-ray cascade paths leading to the ground state in {sup 149}Sm and {sup 148}Sm have been summed (without double counting) to estimate lower limits for reaction cross sections. These lower limits are combined with Hauser-Feshbach model calculations to deduce the reaction channel cross sections. These reaction channel cross sections agree with previously measured experimental and ENDF/B-VII evaluations.

  10. Activation cross-sections of proton induced nuclear reactions on thulium in the 20-45 MeV energy range.

    PubMed

    Tárkányi, F; Hermanne, A; Takács, S; Ditrói, F; Spahn, I; Ignatyuk, A V

    2012-01-01

    Cross-sections of proton induced nuclear reactions on (169)Tm were measured in the 20-45MeV energy range using the standard stacked-foil irradiation technique and high resolution gamma-ray spectroscopy. Experimental cross-sections and derived integral yields are reported for the production of (169,167,166)Yb and (168,167,166)Tm radioisotopes. The experimental data are analysed and compared to results of the earlier measurements and the theoretical model codes ALICE-IPPE, EMPIRE and TALYS. Application of the new cross-sections to the production of the (167)Tm medical radioisotope is discussed. PMID:21920768

  11. Measurement of cross sections for the 63Cu(alpha,gamma)67Ga reaction from 5.9-8.7 MeV

    SciTech Connect

    Basunia, M. Shamsuzzoha; Norman, Eric B.; Shugart, Howard A.; Smith, Alan R.; Dolinski, Michelle J.; Quiter, Brian J.

    2004-09-23

    We have measured cross sections for the 63Cu(alpha,gamma)67Ga reaction in the 5.9-8.7 MeV energy range using an activation technique. Natural Cu foils were bombarded with alpha beams from the 88 Cyclotron at Lawrence Berkeley National Laboratory (LBNL). Activated foils were counted using gamma spectrometry system at LBNL's Low Background Facility. The 63Cu(alpha,gamma)67Ga cross-sections were determined and compared with the latest NON-SMOKER theoretical values. Experimental cross sections were found to be in agreement with theoretical values.

  12. New Evaluated Semi-Empirical Formula Using Optical Model for 14-15 MeV ( n, t) Reaction Cross Sections

    NASA Astrophysics Data System (ADS)

    Tel, E.; Durgu, C.; Aydın, A.; Bölükdemir, M. H.; Kaplan, A.; Okuducu, Ş.

    2009-12-01

    In the next century the world will face the need for new energy sources. Nuclear fusion can be one of the most attractive sources of energy from the viewpoint of safety and minimal environmental impact. Fusion will not produce CO2 or SO2 and thus will not contribute to global warming or acid rain. Achieving acceptable performance for a fusion power system in the areas of economics, safety and environmental acceptability, is critically dependent on performance of the blanket and diverter systems which are the primary heat recovery, plasma purification, and tritium breeding systems. Tritium self-sufficiency must be maintained for a commercial power plant. The hybrid reactor is a combination of the fusion and fission processes. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. So working out the systematics of ( n, t) reaction cross-sections are of great importance for the definition of the excitation function character for the given reaction taking place on various nuclei at energies up to 20 MeV. In this study, we have calculated non-elastic cross-sections by using optical model for ( n, t) reactions at 14-15 MeV energy. We have investigated the excitation function character and reaction Q-values depending on the asymmetry term effect for the ( n, t) reaction cross-sections. We have obtained new coefficients for the ( n, t) reaction cross-sections. We have suggested semi-empirical formulas including optical model nonelastic effects by fitting two parameters for the ( n, t) reaction cross-sections at 14-15 MeV. We have discussed the odd-even effect and the pairing effect considering binding energy systematic of the nuclear shell model for the new experimental data and new cross-sections formulas ( n, t) reactions developed by Tel et al. We have determined a different parameter groups by the classification of nuclei into even-even, even-odd and odd-even for ( n, t) reactions cross-sections. The obtained cross-section formulas

  13. Investigation of 14-15 MeV ( n, t) Reaction Cross-sections by Using New Evaluated Empirical and Semi-empirical Systematic Formulas

    NASA Astrophysics Data System (ADS)

    Tel, E.; Aydın, A.; Kaplan, A.; Şarer, B.

    2008-09-01

    In the hybrid reactor, tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. Working out the systematics of ( n, t) reaction cross-sections are of great importance for the definition of the excitation function character for the given reaction taking place on various nuclei at energies up to 20 MeV. In this study we have investigated asymmetry term effect for the ( n, t) reaction cross-sections at 14-15 neutron incident energy. It has been discussed the odd-even effect and the pairing effect considering binding energy systematic of the nuclear shell model for the new experimental data and new cross-sections formulas ( n, t) reactions developed by Tel et al. We have determined a different parameter groups by the classification of nuclei into even-even, even-odd and odd-even for ( n, t) reactions cross-sections. The obtained empirical and semi-empirical formulas by fitting two parameter for ( n, t) reactions were given. All calculated results have been compared with the experimental data and the other semi-empirical formulas.

  14. Total and partial cross sections of the 112Sn(α ,γ ) 116Te reaction measured via in-beam γ -ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Netterdon, L.; Mayer, J.; Scholz, P.; Zilges, A.

    2015-03-01

    Background: The nucleosynthesis of the neutron-deficient p nuclei remains an open question in nuclear astrophysics. Beside uncertainties on the astrophysical side, the nuclear-physics input parameters entering Hauser-Feshbach calculations for the nucleosynthesis of the p nuclei must be put on a firm basis. Purpose: An extended database of experimental data is needed to address uncertainties of the nuclear-physics input parameters for Hauser-Feshbach calculations. Especially α + nucleus optical model potentials at low energies are not well known. The in-beam technique with an array of high-purity germanium (HPGe) detectors was successfully applied to the measurement of absolute cross sections of an (α ,γ ) reaction on a heavy nucleus at sub-Coulomb energies. Method: The total and partial cross-section values were measured by means of in-beam γ -ray spectroscopy. For this purpose, the absolute reaction yield was measured using the HPGe detector array HORUS at the FN tandem accelerator at the University of Cologne. Total and partial cross sections were measured at four different α -particle energies from Eα=10.5 MeV to Eα=12 MeV . Results: The measured total cross-section values are in excellent agreement with previous results obtained with the activation technique, which proves the validity of the applied method. With the present measurement, the discrepancy between two older data sets is removed. The experimental data was compared to Hauser-Feshbach calculations using the nuclear reaction code talys. With a modification of the semi-microscopic α + nucleus optical model potential OMP 3, the measured cross-section values are reproduced well. Moreover, partial cross sections could be measured for the first time for an (α ,γ ) reaction. Conclusions: A modified version of the semimicroscopic α + nucleus optical model potential OMP3, as well as modified proton and γ widths, are needed in order to obtain a good agreement between experimental data and theory. It

  15. Cross-sectional study exploring barriers to adverse drug reactions reporting in community pharmacy settings in Dhaka, Bangladesh

    PubMed Central

    Amin, Mohammad Nurul; Khan, Tahir Mehmood; Dewan, Syed Masudur Rahman; Islam, Mohammad Safiqul; Moghal, Mizanur Rahman

    2016-01-01

    Objectives To assess community pharmacists'/pharmacy technicians' knowledge and perceptions about adverse drug reactions (ADRs) and barriers towards the reporting of such reactions in Dhaka, Bangladesh. Method A cross-sectional study was planned to approach potential respondents for the study. A self-administered questionnaire was delivered to community pharmacists/pharmacy technicians (N=292) practising in Dhaka, Bangladesh. Results The overall response to the survey was 69.5% (n=203). The majority of the sample was comprised of pharmacy technicians (152, 74.9%) who possessed a diploma in pharmacy, followed by pharmacists (37, 18.2%) and others (12, 5.9%). Overall, 72 (35.5%) of the respondents disclosed that they had experienced an ADR at their pharmacy, yet more than half (105, 51.7%) were not familiar with the existence of an ADR reporting body in Bangladesh. Exploring the barriers to the reporting of ADRs, it was revealed that the top four barriers to ADR reporting were ‘I do not know how to report (Relative Importance Index (RII)=0.998)’, ‘reporting forms are not available (0.996)’, ‘I am not motivated to report (0.997)’ and ‘Unavailability of professional environment to discuss about ADR (RII=0.939)’. In addition to these, a majority (141, 69.46%) were not confident about the classification of ADRs (RII=0.889) and were afraid of legal liabilities associated with reporting ADRs (RII=0.806). Moreover, a lack of knowledge about pharmacotherapy and the detection of ADRs was another major factor hindering their reporting (RII=0.731). Conclusions The Directorate of Drug Administration in Bangladesh needs to consider the results of this study to help it improve and simplify ADR reporting in Bangladeshi community pharmacy settings. PMID:27489151

  16. Radiative thermal neutron-capture cross sections for the 180W(n ,γ ) reaction and determination of the neutron-separation energy

    NASA Astrophysics Data System (ADS)

    Hurst, A. M.; Firestone, R. B.; Szentmiklósi, L.; Sleaford, B. W.; Basunia, M. S.; Belgya, T.; Escher, J. E.; Krtička, M.; Révay, Zs.; Summers, N. C.

    2015-09-01

    Prompt thermal neutron-capture partial γ -ray production cross sections were measured for the first time for the 180W(n ,γ ) reaction using a cold guided-neutron beam at the Budapest Research Reactor. Absolute 181Wγ -ray cross sections were internally standardized using well-known comparator γ -ray cross sections belonging to the other tungsten isotopes present in the 11.35% enriched 180W sample. Transitions were assigned to levels in 181W based largely upon information available in the literature. The total radiative thermal neutron-capture cross section σ0 was determined from the sum of direct prompt γ -ray cross sections populating the ground state and a modeled contribution accounting for ground-state feeding from the quasicontinuum. In this work, we find σ0=21.67 (77 ) b. A new measurement of the cross section for the 5 /2- metastable isomer at 365.6 keV, σ5 /2-(181Wm,14.6 μ s ) =19.96 (55 ) b, is also determined. Additionally, primary γ rays, observed for the first time in the 180W(n ,γ ) reaction, provide the most precise determination for the 181W neutron-separation energy, Sn=6669.02 (16 ) keV.

  17. Calculation of the energy dependence of the fusion cross section and total cross sections for peripheral reactions on the basis of an analysis of data on elastic heavy-ion scattering: Strongly bound ions

    SciTech Connect

    Pozdnyakov, Yu. A.

    2007-09-15

    A method is proposed for calculating the energy dependence of the fusion cross section (in general, the sum of the cross sections for complete and incomplete fusion, quasifission, and reactions of deep-inelastic scattering) {sigma}{sub F}(E) and the total cross section for peripheral (or quasielastic) reactions, {sigma}{sub D}(E). The method is based on an analysis of a limited set of angular distributions for the elastic scattering in a given pair of nuclei. The predictive power of the method is illustrated by considering the {sup 16}O + {sup 208}Pb, {sup 16}O + {sup 40}Ca, and {sup 16}O + {sup 28}Si systems. For each of these systems, the calculations were performed at energies in the range extending from subbarrier values to those exceeding the barrier height substantially. The results of the calculations are found to be in good agreement with relevant experimental data, whereby the reliability of the method is confirmed. By virtue of this, it is proposed to employ the method to study the energy dependences {sigma}{sub F}(E) and {sigma}{sub D}(E) in collisions involving unstable nuclei, for which it is difficult to determine experimentally the above dependences because of a low intensity of secondary beams.

  18. 57Co (n,γ) 58Co reaction cross section: Thermal and resonance integral measurements and energy dependence

    NASA Astrophysics Data System (ADS)

    Maidana, Nora L.; Mesa, Joel; Vanin, Vito R.; Castro, Ruy M.; Dias, Mauro S.; Koskinas, Marina F.

    2004-07-01

    The 57Co (n,γ) 58Co thermal and resonance integral cross section were measured as 51 (5) b and 20.0 (19) b , respectively, by irradiating aliquots of 57Co solution sealed inside quartz bottles near the core of the IEA-R1 IPEN research reactor and counting the gamma-ray residual activity. The irradiations were monitored using Au-Al alloy foils, with and without Cd cover. The gamma-ray measurements were performed with a shielded HPGe detector. Westcott formalism was applied for the average neutron flux determination. The cross section energy dependence was evaluated using the multilevel Breit-Wigner expression considering the first two resonances and the statistical model for energies above the second resonance. Maxwellian averaged neutron capture cross section with neutron temperatures between 5 and 100 keV were also evaluated.

  19. {sup 57}Co(n,{gamma}){sup 58}Co reaction cross section: Thermal and resonance integral measurements and energy dependence

    SciTech Connect

    Maidana, Nora L.; Mesa, Joel; Vanin, Vito R.; Castro, Ruy M.; Dias, Mauro S.; Koskinas, Marina F.

    2004-07-01

    The {sup 57}Co(n,{gamma}){sup 58}Co thermal and resonance integral cross section were measured as 51(5) b and 20.0(19) b, respectively, by irradiating aliquots of {sup 57}Co solution sealed inside quartz bottles near the core of the IEA-R1 IPEN research reactor and counting the gamma-ray residual activity. The irradiations were monitored using Au-Al alloy foils, with and without Cd cover. The gamma-ray measurements were performed with a shielded HPGe detector. Westcott formalism was applied for the average neutron flux determination. The cross section energy dependence was evaluated using the multilevel Breit-Wigner expression considering the first two resonances and the statistical model for energies above the second resonance. Maxwellian averaged neutron capture cross section with neutron temperatures between 5 and 100 keV were also evaluated.

  20. Measurement of neutron capture cross-section of the 71Ga(n, γ) 72Ga reaction at 0.0536 eV energy

    NASA Astrophysics Data System (ADS)

    Uddin, M. S.; Chowdhury, M. H.; Hossain, S. M.; Latif, Sk. A.; Hafiz, M. A.; Islam, M. A.; Zakaria, A. K. M.; Yunus, S. M.; Azharul Islam, S. M.

    2008-08-01

    The neutron capture cross-section for the 71Ga(n, γ) 72Ga reaction at 0.0536 eV energy was measured using activation technique based on TRIGA Mark-II research reactor. The 197Au(n, γ) 198Au monitor reaction was used to determine the effective neutron flux. Neutron absorption and γ-ray attenuation in gallium oxide pellet were corrected in determination of cross-section. The cross-section for the above reaction at 0.0536 eV amounts to 2.75 ± 0.14 b. As far as we know there are no experimental data available at our investigated energy. So far we are the first, who carried out experiment with 0.0536 eV neutrons for cross-section measurement. The present result is larger than that of JENDL-3.3, but consistent within the uncertainty range. The value of ENDF/B-VII is higher than this work. The result of this work will be useful to observe energy dependence of neutron capture cross-sections.

  1. Production cross sections of products in the proton induced reactions on natNd in the energy region up to 45 MeV

    NASA Astrophysics Data System (ADS)

    Yang, Sung-Chul; Kim, Kwangsoo; Song, Tae-Yung; Lee, Young-Ouk; Kim, Guinyun

    2015-11-01

    The production cross sections of 141,143,144,146,148m,148g,149,150Pm, 139m,147,149Nd, 138m,142gPr, and 139gCe in the natNd(p,x) reactions were determined by a stacked-foil activation technique for the proton energy range up to 45 MeV using the MC-50 cyclotron of Korea Institute of Radiological and Medical Sciences. The measured cross sections were compared with literature data as well as data from the TENDL-2014 library based on TALYS 1.6. The production cross sections of the above radionuclides are slightly higher than the literature data but are in general agreement with values in TENDL-2014 library except for 148mPm, 148gPm, 139mNd, and 142gPr. The thick target integral yields of the produced radionuclides were also deducted from the measured cross sections.

  2. Cross sections for the γp \\to K^{*+} Lambda$ and $γp \\to K^{*+} Sigma^{0}$ reactions measured at CLAS

    SciTech Connect

    Tang, Wei; Hicks, Kenneth. H.; Keller, Dustin M.; Kim, S.-H.; Kim, H.-C.

    2013-06-01

    The first high-statistics cross sections for the reactions $\\gamma p \\to K^{*+} \\Lambda$ and $\\gamma p \\to K^{*+} \\Sigma^0$ were measured using the CLAS detector at photon energies between threshold and 3.9 GeV at the Thomas Jefferson National Accelerator Facility. Differential cross sections are presented over the full range of the center-of-mass angles, $\\theta^{CM}_{K^{*+}}$, and then fitted to Legendre polynomials to extract the total cross section. Results for the $K^{*+}\\Lambda$ final state are compared with two different calculations in an isobar and a Regge model, respectively. Theoretical calculations significantly underestimate the $K^{*+} \\Lambda$ total cross sections between 2.1 and 2.6 GeV, but are in better agreement with present data at higher photon energies.

  3. Angle-integrated measurements of the 26Al (d, n)27Si reaction cross section: a probe of spectroscopic factors and astrophysical resonance strengths

    NASA Astrophysics Data System (ADS)

    Kankainen, A.; Woods, P. J.; Nunes, F.; Langer, C.; Schatz, H.; Bader, V.; Baugher, T.; Bazin, D.; Brown, B. A.; Browne, J.; Doherty, D. T.; Estrade, A.; Gade, A.; Kontos, A.; Lotay, G.; Meisel, Z.; Montes, F.; Noji, S.; Perdikakis, G.; Pereira, J.; Recchia, F.; Redpath, T.; Stroberg, R.; Scott, M.; Seweryniak, D.; Stevens, J.; Weisshaar, D.; Wimmer, K.; Zegers, R.

    2016-01-01

    Measurements of angle-integrated cross sections to discrete states in 27Si have been performed studying the 26Al ( d, n) reaction in inverse kinematics by tagging states by their characteristic γ -decays using the GRETINA array. Transfer reaction theory has been applied to derive spectroscopic factors for strong single-particle states below the proton threshold, and astrophysical resonances in the 26Al ( p, γ) 27Si reaction. Comparisons are made between predictions of the shell model and known characteristics of the resonances. Overall very good agreement is obtained, indicating this method can be used to make estimates of resonance strengths for key reactions currently largely unconstrained by experiment.

  4. Cross sections for vibrational inhibition at low collision energies for the reaction H + Li2(X1Σ{g/+}) → Li + LiH (X1Σ+)

    NASA Astrophysics Data System (ADS)

    Gao, Shoubao; Zhang, Jing; Song, Yuzhi; Meng, Qing-Tian

    2015-05-01

    A time-dependent wave packet dynamics study of the H + Li2 reaction has been performed on the novel HLi2(X2A') potential energy surface [Y.Z. Song, Y.Q. Li, S.B. Gao, Q.T. Meng, Eur. Phys. J. D 68, 1 (2014)]. The v-dependent reaction probabilities and integral cross sections are presented as a function of collision energies. From the v-dependent behaviour of integral cross sections, it can be seen that the vibrational excitation of the reactant Li2 hinders the reactivity at low collision energies. Furthermore, the comparison of j-dependent reaction probabilities indicates that Li2 rotation also hinders the reaction.

  5. Neutron capture cross-section measurement for the 186W(n,gamma)187W reaction at 0.0536eV energy.

    PubMed

    Uddin, M S; Chowdhury, M H; Hossain, S M; Latif, Sk A; Hafiz, M A; Islam, M A; Zakaria, A K M; Azharul Islam, S M

    2008-09-01

    The thermal neutron-induced activation cross section for the (186)W(n,gamma)(187)W reaction was measured at 0.0536eV neutron energy using TRIGA Mark-II research reactor, Atomic Energy Research Establishment, Savar, Dhaka, Bangladesh. The (197)Au(n,gamma)(198)Au monitor reaction induced in a high-purity gold foil was used to determine the effective neutron beam intensity. The activities induced in sample and monitor foils were measured nondestructively by a high-resolution HPGe gamma-ray detector. The present experimental cross-section value is the first one at 0.0536eV. The obtained new cross section that amounts to 26.6+/-1.6b is 2% higher than the recently reported data in ENDF/B-VII and 5% lower than that of JENDL-3.3. PMID:18325774

  6. Cross sections of ground and isomeric states for (n,p) reaction on Sm-154 between 13.57 and 14.83MeV neutrons.

    PubMed

    Reyhancan, Iskender Atilla

    2016-07-01

    In this study, the activation cross sections were measured for the (154)Sm(n,p)(154g)Pm, and (154)Sm(n,p)(154m)Pm reactions at several neutron energies between 13.57 and 14.83MeV, which were produced by the neutron generator (SAMES T-400) through the (3)H((2)H,n)(4)He reaction. The production of short-lived activity and the spectra accumulation were performed by the cyclic activation technique. Induced gamma-ray activities were measured using a high resolution gamma ray spectrometer equipped with a high-purity Germanium (HPGe) detector. In the cross section measurements, corrections were made regarding the effects of gamma-ray attenuation, dead-time, fluctuation of neutron flux, and low energy neutrons. The measured cross sections were compared with data reported in literature as well as model calculations using the code TALYS 1.6. PMID:27149398

  7. Solving the Large Discrepancy Between Inclusive and Exclusive Measurements of the 8Li + 4He → 11B + n Reaction Cross Section at Astrophysical Energies

    NASA Astrophysics Data System (ADS)

    La Cognata, M.; Del Zoppo, A.; Alba, R.; Cherubini, S.; Colonna, N.; Di Pietro, A.; Figuera, P.; Gulino, M.; Lamia, L.; Musumarra, A.; Pellegriti, M. G.; Pizzone, R. G.; Rolfs, C.; Romano, S.; Spitaleri, C.; Tumino, A.

    2009-12-01

    A solution of the large discrepancy existing between inclusive and exclusive measurements of the 8Li + 4He → 11B + n reaction cross section at E cm < 3 MeV is evaluated. This problem has profound astrophysical relevance for this reaction is of great interest in big bang and r-process nucleosynthesis. By means of a novel technique, a comprehensive study of all existing 8Li + 4He → 11B + n cross section data is carried out, setting up a consistent picture in which all the inclusive measurements provide the reliable value of the cross section. New unambiguous signatures of the strong branch pattern non-uniformities, near the threshold of higher 11B excited levels, are presented and their possible origin, in terms of the cluster structure of the involved excited states of 11B and 12Bnuclei, is discussed.

  8. Calculation of the evaporation residue cross sections for the synthesis of the superheavy element Z=119 via the {sup 50}Ti+{sup 249}Bk hot fusion reaction

    SciTech Connect

    Liu Zuhua; Bao, Jing-Dong

    2011-09-15

    The evaporation residue (ER) cross sections for 3n and 4n evaporation channels in the {sup 50}Ti + {sup 249}Bk reaction leading the formation of {sup 296}119 and {sup 295}119 isotopes are evaluated by means of a modified fusion-by-diffusion model. In the model, the dynamic evolution from dinucleus to mononucleus is taken into account with the two-dimensional coupled Langenvin equations. The calculated maximum ER cross sections in 3n and 4n evaporation channels of the {sup 50}Ti + {sup 249}Bk reaction are 0.17 and 0.57 pb, respectively. The cross section of 0.57 pb is close to the present experimental limit for the registration of the evaporation residual nuclei. Therefore, superheavy element 119 may be the most hopeful new element with Z>118 to be synthesized under somehow improved experimental conditions in the near future.

  9. Measurements of isomeric cross sections for the (n,α) reaction on the ¹⁴²Nd isotope at approximately 14 MeV neutrons.

    PubMed

    Reyhancan, Iskender Atilla

    2014-09-01

    In this study, the activation cross sections were measured for (142)Nd(n,α)(139m)Ce reaction at four neutron energies between 13.57 and 14.83 MeV, which were produced by a neutron generator through (3)H((2)H,n)(4)He reaction. The production of short-lived activity and the spectra accumulation were performed by the cyclic activation technique. Induced gamma-ray activities were measured using a high resolution gamma ray spectrometer equipped with a high-purity Germanium (HpGe) detector. In the cross section measurements, corrections were made regarding the effects of the gamma-ray attenuation, the dead-time, the fluctuation of the neutron flux, and low energy neutrons. The measured cross sections were compared with the published literature and the results of the model calculation (TALYS 1.4). PMID:24886965

  10. Recent fission cross section standards measurements

    SciTech Connect

    Wasson, O.A.

    1985-01-01

    The /sup 235/U(n,f) reaction is the standard by which most neutron induced fission cross sections are determined. Most of these cross sections are derived from relatively easy ratio measurements to /sup 235/U. However, the more difficult /sup 235/U(n,f) cross section measurements require the use of advanced neutron detectors for the determination of the incident neutron fluence. Examples of recent standard cross section measurements are discussed, various neutron detectors are described, and the status of the /sup 235/U(n,f) cross section standard is assessed. 23 refs., 8 figs., 4 tabs.

  11. Neutron Capture Cross Section of 90Zr: Bottleneck in the s-Process Reaction Flow

    SciTech Connect

    Tagliente, G.; Koehler, Paul Edward; Collaboration, n_TOF

    2008-03-01

    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 {sup 90}Zr, 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,{gamma}) 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 {Lambda}{sub {gamma}}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 for s-process calculations has been improved by more than a factor of 2.

  12. Quantum mechanical calculations of state-to-state cross sections and rate constants for the F + DCl → Cl + DF reaction

    SciTech Connect

    Bulut, Niyazi; Kłos, Jacek; Roncero, Octavio

    2015-06-07

    We present accurate state-to-state quantum wave packet calculations of integral cross sections and rate constants for the title reaction. Calculations are carried out on the best available ground 1{sup 2}A′ global adiabatic potential energy surface of Deskevich et al. [J. Chem. Phys. 124, 224303 (2006)]. Converged state-to-state reaction cross sections have been calculated for collision energies up to 0.5 eV and different initial rotational and vibrational excitations, DCl(v = 0, j = 0 − 1; v = 1, j = 0). Also, initial-state resolved rate constants of the title reaction have been calculated in a temperature range of 100-400 K. It is found that the initial rotational excitation of the DCl molecule does not enhance reactivity, in contract to the reaction with the isotopologue HCl in which initial rotational excitation produces an important enhancement. These differences between the isotopologue reactions are analyzed in detail and attributed to the presence of resonances for HCl(v = 0, j), absent in the case of DCl(v = 0, j). For vibrational excited DCl(v = 1, j), however, the reaction cross section increases noticeably, what is also explained by another resonance.

  13. Differential and angle-integrated cross sections for the 40Ca(n, α)37Ar reaction from 4.0 to 6.5 MeV

    NASA Astrophysics Data System (ADS)

    Han, Jinhua; Liu, Jiaming; Liu, Xiang; Fan, Xiao; Wang, Zhimin; Chen, Jinxiang; Zhang, Guohui; Gledenov, Yu. M.; Sedysheva, M. V.; Krupa, L.; Khuukhenkhuu, G.; Szalanski, P. J.

    2015-01-01

    Differential cross sections for the 40 Ca( n,) , and reactions are measured at neutron energies of 4.0, 4.5, 5.0, 5.5, 6.0 and 6.5MeV using a double-section gridded ionization chamber and two CaF2 samples. Monoenergetic neutrons were produced through the 2 H( d, n)3 He reaction with a deuterium gas target. A BF3 neutron counter was utilized to normalize the neutron flux among different measurements. The absolute value of neutron flux was calibrated using a 238U sample. Angle-integrated cross sections for the 40 Ca( n,) , and reactions are obtained from the integration of the differential data. Model calculations are performed using the TALYS-1.6 code and general agreement is achieved between measurements and calculations. Then the total 40Ca( n,)37Ar cross sections are derived from the angle-integrated cross sections combined with the code calculations. Present results are compared with existing measurements and evaluations.

  14. Cross-section measurement for the /sup 7/Li(n,n't)/sup 4/He reaction at 14. 74 MeV

    SciTech Connect

    Smith, D.L.; Meadows, J.W.; Bretscher, M.M.; Cox, S.A.

    1984-09-01

    The cross section for the /sup 7/Li(n,n't)/sup 4/He reaction is measured at an average neutron energy of 14.74 MeV, with a resolution of 0.324 MeV, relative to the /sup 238/U neutron-fission cross section. Tritium activities for the irradiated lithium-metal samples (enriched to 99.95% in /sup 7/Li) are deduced using a liquid-scintillation counting method which relies upon the tritiated-water standard from the US National Bureau of Standards. The measured cross section ratio of /sup 7/Li(n,n't)/sup 4/He to /sup 238/U neutron fission is 0.2523 (+- 2.2%). The derived /sup 7/Li(n,n't)/sup 4/He reaction cross section is 0.301 (+- 5.3%) barn, based on the ENDF/B-V value of 1.193 (+- 4.8%) barn for the /sup 238/U neutron-fission cross section. 59 references.

  15. {sup 48}Ti(n,xnpa{gamma}) reaction cross sections using spallation neutrons for E{sub n} = 1 to 20 MeV

    SciTech Connect

    Dashdorj, D; Mitchell, G E; Garrett, P E; Agvaanluvsan, U; Becker, J A; Bernstein, L A; Cooper, J R; Hoffman, R D; Younes, W; Devlin, N; Fotiades, N; Nelson, R O

    2005-01-06

    {gamma}-ray excitation functions have been measured for the interaction of fast neutrons with {sup 48}Ti (neutron energy from 1 MeV to 250 MeV). The Los Alamos National Laboratory spallation neutron source, at the LANSCE/WNR facility, provided a ''white'' neutron beam which is produced by bombarding a natural W target with a pulsed proton beam. The prompt-reaction {gamma} rays were measured with the large-scale Compton-suppressed Ge spectrometer, GEANIE. Neutron energies were determined by the time-of-flight technique. Excitation functions were converted to partial {gamma}-ray cross sections, taking into account the dead-time correction, the target thickness, the detector efficiency, and neutron flux (monitored with an in-line fission chamber). The data analysis is presented here for neutron energies between 1 to 20 MeV. Partial {gamma}-ray cross sections for transitions in {sup 47,48}Ti, {sup 48}Sc, and {sup 45}Ca have been determined. These results are compared to Hauser-Feshbach predictions calculated using the STAPRE code, which includes compound nuclear and pre-equilibrium emission. The partial cross sections for {gamma} rays, whose discrete {gamma}-ray cascade path leads to the ground state in {sup 48}Ti, {sup 47}Ti, {sup 48}Sc, and {sup 45}Ca have been summed to obtain estimates of the lower limits for reaction cross sections. Partial cross sections for unobserved {gamma}-rays are predicted from the STAPRE code. These lower limits are combined with Hauser-Feshbach calculations to deduce {sup 48}Ti(n,n'){sup 48}Ti, {sup 48}Ti(n,2n){sup 47}Ti, {sup 48}Ti(n,p){sup 48}Sc, and {sup 48}Ti(n,{alpha}){sup 45}Ca reaction channel cross sections.

  16. Cross Section Evaluations for Arsenic Isotopes

    SciTech Connect

    Pruet, J; McNabb, D P; Ormand, W E

    2005-03-10

    The authors present an evaluation of cross sections describing reactions with neutrons incident on the arsenic isotopes with mass numbers 75 and 74. Particular attention is paid to (n,2n) reactions. The evaluation for {sup 75}As, the only stable As isotope, is guided largely by experimental data. Evaluation for {sup 74}As is made through calculations with the EMPIRE statistical-model reaction code. Cross sections describing the production and destruction of the 26.8 ns isomer in {sup 74}As are explicitly considered. Uncertainties and covariances in some evaluated cross sections are also estimated.

  17. Cross section for the reaction {sup 115}In(γ, γ′){sup 115m} In in the region of the E1 giant resonance

    SciTech Connect

    Dzhilavyan, L. Z.

    2015-07-15

    The cross section for the reaction {sup 115}In(γ, γ′){sub 115m}In was measured for photon energies in the range of E{sub γ} ≅ 4–46 MeV. The parameters of the peak in this cross section near the threshold for the reaction {sup 115}In(γ, n), (E{sub γ}){sub (γ,n)}{sup thr}, were refined. It is shown that, in the cross section for the reaction {sup 115}In(γ, γ′){sup 115m}In at Eγ ∼ 27 MeV, there is no second peak for which δ{sub II}{sup int} would exceed about 0.2δ{sub I}{sup int} for the peak at E{sub γ} ∼ (E{sub γ}){sub (γ,n)}{sup thr}. The possibility of employing this reaction both in studying photonuclear reaction physics and in monitoring bremsstrahlung photons in gamma-activation studies was examined.

  18. Reaction cross sections and thermal rate constant for Cl(-) + CH3Br → ClCH3 + Br(-) from J-dependent quantum scattering calculations.

    PubMed

    Hennig, Carsten; Schmatz, Stefan

    2016-07-20

    Employing dimensionality-reduced time-independent quantum scattering theory and summation over all possible total angular momentum states, initial-state selected reaction cross sections for the exothermic gas-phase bimolecular nucleophilic substitution (SN2) reaction Cl(-) + CH3Br → ClCH3 + Br(-) have been calculated. The carbon-halogen bonds and the rotation of the methyl halides are taken into account. In agreement with previous calculations for J = 0, initial rotational motion of CH3Br decreases the reaction probability and consequently the cross sections. The experimentally obtained thermal rate constant for 300 K is reproduced within the experimental error. For lower temperatures, it is calculated to be below the experimental values but shows the same strong increase for T → 0. PMID:27381461

  19. Activation cross sections of proton and deuteron induced nuclear reactions on holmium and erbium, related to the production of (161)Er and (160)Er medical isotopes.

    PubMed

    Tárkányi, F; Ditrói, F; Takács, S; Hermanne, A; Baba, M

    2016-09-01

    Experimental excitation functions for long-lived products in proton induced reactions were measured with the activation method in the 37-65MeV energy range on natural holmium. Stacked foil irradiation technique and high resolution gamma spectrometry were used in order to measure cross-section data for the production of (161)Er, (160)Er and (1)(59,157)Dy. For comparison of the production routes of medically related (161)Er and (160)Er radioisotopes new experimental cross section data were deduced for the (162)Er(p,x)(161,160)Er and (162)Er(d,x)(161,160)Er reactions by re-evaluating gamma-ray spectra from earlier measurements. No earlier data were found in the literature for these reactions. The experimental data are compared with results of TALYS theoretical code reported in TENDL-2015. PMID:27451109

  20. The (3He,tf) as a surrogate reaction to determine (n,f) cross sections in the 10 to 20 MeV energy range

    SciTech Connect

    Basunia, M. S.; Clark, R. M.; Goldblum, B. L.; Bernstein, L. A.; Phair, L.; Burke, J. T.; Beausang, C. W.; Bleuel, D. L.; Darakchieva, B.; Dietrich, F. S.; Evtimova, M.; Fallon, P.; Gibelin, J.; Hatarik, R.; Jewett, C. C.; Lesher, S. R.; McMahan, M. A.; Rodriguez-Vieitez, E.; Wiedeking, M.

    2009-02-25

    The surrogate reaction 238U(3He,tf) is used to determine the 237Np(n,f) cross section indirectly over an equivalent neutron energy range from 10 to 20 MeV. A self-supporting ~;;761 mu g/cm2 metallic 238U foil was bombarded with a 42 MeV 3He2+ beam from the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory (LBNL). Outgoing charged particles and fission fragments were identified using the Silicon Telescope Array for Reaction Studies (STARS), consists of two 140 mu m and one 1000 mu m Micron S2 type silicon detectors. The 237Np(n,f) cross sections, determined indirectly, were compared with the 237Np(n,f) cross section data from direct measurements, the Evaluated Nuclear Data File (ENDF/B-VII.0), and the Japanese Evaluated Nuclear Data Library (JENDL 3.3) and found to closely follow those datasets. Use of the (3He,tf) reaction as a surrogate to extract (n,f) cross section in the 10 to 20 MeV equivalent neutron energy is found to be suitable.

  1. Measurement of flux-weighted average cross sections for 197Au(γ, xn) reactions and isomeric yield ratios of 196m,gAu with bremsstrahlung

    NASA Astrophysics Data System (ADS)

    Naik, Haladhara; Kim, Guinyun; Kim, Kwangsoo; Zaman, Muhammad; Goswami, Ashok; Lee, Man Woo; Yang, Sung-Chul; Lee, Young-Ouk; Shin, Sung-Gyun; Cho, Moo-Hyun

    2016-04-01

    Photo-neutron cross sections of 197Au were experimentally determined for the bremsstrahlung end-point energies of 50, 60, and 70 MeV, by utilizing activation and off-line γ-ray spectrometric technique, using the 100 MeV electron linac at the Pohang Accelerator Laboratory (PAL), Pohang, Korea. The 197Au(γ, xn; x = 1- 6) reaction cross sections were calculated as a function of the bombarding photon energy by using the TALYS 1.6 computer code with default parameters. The flux-weighted average cross sections were obtained from the literature data and the theoretical values of TALYS 1.6 and TENDL-2014, for mono-energetic photons, and are found to be in good agreement with the present data. Isomeric yield ratios of 196m2,gAu from the 197Au(γ, n) reaction were also determined for the bremsstrahlung end-point energies of 50, 60, and 70 MeV, from the reaction cross sections of m2- and g-states, based on the present experimental data, and are found to be in good agreement with the theoretical values based on TALYS 1.6 and TENDL-2014.

  2. Calculation of proton total reaction cross sections for some target nuclei in incident energy range of 10-600 MeV

    SciTech Connect

    Bueyuekuslu, H.; Kaplan, A.; Aydin, A.; Tel, E.; Yildirim, G.

    2010-10-15

    In this study, proton total reaction cross sections have been investigated for some isotopes such as {sup 12}C, {sup 27}Al, {sup 9}Be, {sup 16}O, {sup 181}Ta, {sup 197}Au, {sup 6}Li, and {sup 14}N by a proton beam up to 600 MeV. Calculation of the proton total cross sections has been carried out by the analytic expression formulated by M.A. Alvi by using Coulomb-modified Glauber theory with the Helm model nuclear form factor. The obtained results have been discussed and compared with the available experimental data and found to be in agreement with each other.

  3. Influence of the constant and density-dependent scaling of the scattering cross-section on reaction dynamics

    NASA Astrophysics Data System (ADS)

    Kaur, Mandeep; Gautam, Sakshi

    2016-02-01

    We investigate the relative effect of constant scaling and density-dependent scaling of the energy-dependent cross-sections on the dynamics of heavy-ion collisions. We carried out our calculations using the isospin-dependent quantum molecular dynamics (IQMD) model and study various observables/non-observables such as collision rate, participant matter, directed transverse flow and its disappearance, nuclear stopping, fragmentation pattern, baryonic entropy, etc. Our investigations indicate that the method used to scale the cross-sections has a sizeable effect on the directed transverse flow and its disappearance in the entire energy range, and on nuclear stopping at higher beam energies only. On the other hand, the rest of the quantities (one-body as well as many-body) remain almost insensitive.

  4. A measurement of the differential cross section for the reaction $\\gamma n \\to \\pi^{-} p$ from deuterium

    SciTech Connect

    W. Chen, T. Mibe, D. Dutta, H. Gao, J.M. Laget, M. Mirazita, P. Rossi, S. Stepanyan, I.I. Strakovsky, et al

    2009-07-01

    We report a measurement of the differential cross section for the $\\gamma n \\to \\pi^- p$ process from the CLAS detector at Jefferson Lab in Hall B for photon energies between 1.0 and 3.5 GeV and pion center-of-mass (c.m.) angles ($\\theta_{c.m.}$) between 50$^\\circ$ and 115$^\\circ$. We confirm a previous indication of a broad enhancement around a c.m. energy ($\\sqrt{s}$) of 2.2 GeV at $\\theta_{c.m.}=90^\\circ$ in the scaled differential cross section, $s^7 {\\frac{d\\sigma}{dt}}$. Our data show the angular dependence of this enhancement as the scaling region is approached in the kinematic region from 70$^\\circ$ to 105$^\\circ$.

  5. Isotopic production cross sections of spallation-evaporation residues from reactions of {sup 238}U(1A GeV) with deuterium

    SciTech Connect

    Casarejos, E.; Benlliure, J.; Pereira, J.; Armbruster, P.; Enqvist, T.; Schmidt, K.-H.; Bernas, M.; Mustapha, B.; Rejmund, F.; Stephan, C.; Taieb, J.; Tassan-Got, L.; Boudard, A.; Legrain, R.; Leray, S.; Volant, C.; Wlazlo, W.

    2006-10-15

    Isotopic production cross sections and momentum distributions of 602 residual nuclei produced in the collision of {sup 238}U(1A GeV) with deuterium have been measured. These data are relevant for a better understanding of spallation reactions for use as neutron sources for accelerator-driven systems or to produce radioactive nuclear beams. Access to primary residue production makes it possible to study the main reaction mechanisms involved: intranuclear cascade, particle evaporation, and fission. The characteristics of the reaction investigated and the high fissility of the {sup 238}U and the dinucleon projectile system are discussed and compared with other available experimental data.

  6. Cross-section measurements for (n, 2n) and (n, alpha) reactions on yttrium at neutron energies from 13.5 to 14.6 MeV.

    PubMed

    Zhou, Fengqun; Zhang, Hongwei; Huang, Hongchun; Li, Kuohu; Yi, Yanling; Tuo, Fei; Kong, Xiangzhong

    2008-12-01

    The cross sections for the reactions (89)Y(n, 2n) (88m+g)Y and (89)Y(n, alpha) (86m+g)RB induced by 14MeV neutrons have been measured using the activation technique and a coaxial HPGe gamma-ray detector. Spectroscopically pure Y(2)O(3) powder was used. Fast neutrons were produced by the T(d, n) (4)He reaction. The neutron fluencies were determined using the monitor reaction (93)Nb(n, 2n) (92m)Nb. PMID:18650098

  7. Determination of 238Pu(n ,f ) and 236Np(n ,f ) cross sections using surrogate reactions

    NASA Astrophysics Data System (ADS)

    Pal, A.; Santra, S.; Nayak, B. K.; Mahata, K.; Desai, V. V.; Chattopadhyay, D.; Tripathi, R.

    2015-05-01

    The cross sections for 238Pu(n ,f ) reaction for equivalent neutron energy of 13.0-22.0 MeV have been determined by the "surrogate ratio" method by measuring 235U(6Li,d f ) and 232Th(6Li,d f ) transfer induced fission reactions proceeding through the excited fissioning nuclei 239Pu and 236U, respectively, and using 235U(n ,f ) cross-section data as the reference. Similarly, the cross sections for the 236Np(n ,f ) reaction in the equivalent neutron energy range 9.9-22.0 MeV have been determined by the "hybrid surrogate ratio" method via the measurements of 235U(6Li,α f ) and 235U(6Li,d f ) transfer induced fission reactions, using 238Pu(n ,f ) cross-section data as the reference. The empire-3.1 calculations for 238Pu(n ,f ) and 236Np(n ,f ) cross sections agree well with the present data, however, they are slightly underestimated by the endf/b-vii.1 evaluations.

  8. Measurement of reaction cross-sections for 89Y at average neutron energies of 7.24-24.83 MeV

    NASA Astrophysics Data System (ADS)

    Zaman, Muhammad; Kim, Guinyun; Naik, Haladhara; Kim, Kwangsoo; Shahid, Muhammad

    2015-05-01

    We measured neutron-induced reaction cross-sections for 89Y(n,γ)90mY and 89Y(n,α)86Rb reactions with the average neutron energy region from 7.45 to 24.83 MeV by an activation and off-line γ-ray spectrometric technique using the MC-50 Cyclotron at Korea Institute of Radiological and Medical Sciences. The neutron-induced reaction cross-sections of 89Y as a function of neutron energy were taken from the TENDL-2013 library. The flux-weighted average cross-sections for 89Y(n,γ)90mY and 89Y(n,α)86Rb reactions were calculated from the TENDL-2013 values based on mono-energetic neutron and by using the neutron energy spectrum from MCNPX 2.6.0 code. The present results are compared with the flux-weighted values of TENDL-2013 and are found to be in good agreement

  9. Product PCNPsurv or the "reduced" evaporation residue cross section σER/σfusion for "hot" fusion reactions studied with the dynamical cluster-decay model

    NASA Astrophysics Data System (ADS)

    Chopra, Sahila; Kaur, Arshdeep; Hemdeep, Gupta, Raj K.

    2016-04-01

    The product PCNPsurv of compound nucleus (CN) fusion probability PCN and survival probability Psurv is calculated to determine the reduced evaporation residue cross section σER/σfusion , denoted σERreduced, with (total) fusion cross section σfusion given as a sum of CN-formation cross section σCN and non-CN cross section σnCN for each reaction, where σCN is the sum of evaporation residue cross section σER and fusion-fission cross section σff and σnCN, if not measured, is estimated empirically as the difference between measured and calculated σfusion. Our calculations of PCN and Psurv, based on the dynamical cluster-decay model, were successfully made for some 17 "hot" fusion reactions, forming different CN of mass numbers ACN˜100 -300 , with deformations of nuclei up to hexadecapole deformations and "compact" orientations for both coplanar (Φc=0∘ ) and noncoplanar (Φc≠0∘ ) configurations, using various different nuclear interaction potentials. Interesting variations of σERreduced with CN excitation energy E*, fissility parameter χ , CN mass ACN, and Coulomb parameter Z1Z2 show that, independent of entrance channel, different isotopes of CN, and nuclear interaction potentials used, the dominant quantity in the product is Psurv, which classifies all the studied CN into three groups of weakly fissioning, radioactive, and strongly fissioning superheavy nuclei, with relative magnitudes of σERreduced˜1 , ˜10-6 , and ˜10-11 , which, like for PCN, get further grouped in two dependencies of (i) weakly fissioning and strongly fissioning superheavy nuclei decreasing with increasing E* and (ii) radioactive nuclei increasing with increasing E*.

  10. A nuclear cross section data handbook

    SciTech Connect

    Fisher, H.O.M.

    1989-12-01

    Isotopic information, reaction data, data availability, heating numbers, and evaluation information are given for 129 neutron cross-section evaluations, which are the source of the default cross sections for the Monte Carlo code MCNP. Additionally, pie diagrams for each nuclide displaying the percent contribution of a given reaction to the total cross section are given at 14 MeV, 1 MeV, and thermal energy. Other information about the evaluations and their availability in continuous-energy, discrete-reaction, and multigroup forms is provided. The evaluations come from ENDF/B-V, ENDL85, and the Los Alamos Applied Nuclear Science Group T-2. Graphs of all neutron and photon production cross-section reactions for these nuclides have been categorized and plotted. 21 refs., 5 tabs.

  11. Neutron Thermal Cross Sections, Westcott Factors, Resonance Integrals, Maxwellian Averaged Cross Sections and Astrophysical Reaction Rates Calculated from the ENDF/B-VII.1, JEFF-3.1.2, JENDL-4.0, ROSFOND-2010, CENDL-3.1 and EAF-2010 Evaluated Data Libraries

    SciTech Connect

    Pritychenko, B.; Mughabghab, S.F.

    2012-12-15

    We present calculations of neutron thermal cross sections, Westcott factors, resonance integrals, Maxwellian-averaged cross sections and astrophysical reaction rates for 843 ENDF materials using data from the major evaluated nuclear libraries and European activation file. Extensive analysis of newly-evaluated neutron reaction cross sections, neutron covariances, and improvements in data processing techniques motivated us to calculate nuclear industry and neutron physics quantities, produce s-process Maxwellian-averaged cross sections and astrophysical reaction rates, systematically calculate uncertainties, and provide additional insights on currently available neutron-induced reaction data. Nuclear reaction calculations are discussed and new results are presented. Due to space limitations, the present paper contains only calculated Maxwellian-averaged cross sections and their uncertainties. The complete data sets for all results are published in the Brookhaven National Laboratory report.

  12. Neutron Thermal Cross Sections, Westcott Factors, Resonance Integrals, Maxwellian Averaged Cross Sections and Astrophysical Reaction Rates Calculated from the ENDF/B-VII.1, JEFF-3.1.2, JENDL-4.0, ROSFOND-2010, CENDL-3.1 and EAF-2010 Evaluated Data Libraries

    NASA Astrophysics Data System (ADS)

    Pritychenko, B.; Mughabghab, S. F.

    2012-12-01

    We present calculations of neutron thermal cross sections, Westcott factors, resonance integrals, Maxwellian-averaged cross sections and astrophysical reaction rates for 843 ENDF materials using data from the major evaluated nuclear libraries and European activation file. Extensive analysis of newly-evaluated neutron reaction cross sections, neutron covariances, and improvements in data processing techniques motivated us to calculate nuclear industry and neutron physics quantities, produce s-process Maxwellian-averaged cross sections and astrophysical reaction rates, systematically calculate uncertainties, and provide additional insights on currently available neutron-induced reaction data. Nuclear reaction calculations are discussed and new results are presented. Due to space limitations, the present paper contains only calculated Maxwellian-averaged cross sections and their uncertainties. The complete data sets for all results are published in the Brookhaven National Laboratory report.

  13. ( γ, 2n)-Reaction cross-section calculations of several even-even lanthanide nuclei using different level density models

    NASA Astrophysics Data System (ADS)

    Kaplan, A.; Sarpün, İ. H.; Aydın, A.; Tel, E.; Çapalı, V.; Özdoǧan, H.

    2015-01-01

    There are several level density models that can be used to predict photo-neutron cross sections. Some of them are Constant Temperature + Fermi Gas Model (CTFGM), Back-Shifted Fermi Gas Model (BSFM), Generalized Superfluid Model (GSM), Hartree-Fock-Bogoliubov microscopic Model (HFBM). In this study, the theoretical photo-neutron cross sections produced by ( γ, 2 n) reactions for several eveneven lanthanide nuclei such as 140,142Ce, 142,144,146,148,150Nd, 144,148,150,152,154Sm, and 160Gd have been calculated on the different level density models as mentioned above by using TALYS 1.6 and EMPIRE 3.1 computer codes for incident photon energies up to 30 MeV. The obtained results have been compared with each other and available experimental data existing in the EXFOR database. Generally, at least one level density model cross-section calculations are in agreement with the experimental results for all reactions except 144Sm( γ, 2 n)142Sm along the incident photon energy, TALYS 1.6 BSFM option for the level density model cross-section calculations can be chosen if the experimental data are not available or are improbable to be produced due to the experimental difficulty.

  14. (γ, 2n)-Reaction cross-section calculations of several even-even lanthanide nuclei using different level density models

    SciTech Connect

    Kaplan, A.; Sarpün, İ. H.; Aydın, A.; Tel, E.; Çapalı, V.; Özdoǧan, H.

    2015-01-15

    There are several level density models that can be used to predict photo-neutron cross sections. Some of them are Constant Temperature + Fermi Gas Model (CTFGM), Back-Shifted Fermi Gas Model (BSFM), Generalized Superfluid Model (GSM), Hartree-Fock-Bogoliubov microscopic Model (HFBM). In this study, the theoretical photo-neutron cross sections produced by (γ, 2n) reactions for several eveneven lanthanide nuclei such as {sup 140,142}Ce, {sup 142,144,146,148,150}Nd, {sup 144,148,150,152,154}Sm, and {sup 160}Gd have been calculated on the different level density models as mentioned above by using TALYS 1.6 and EMPIRE 3.1 computer codes for incident photon energies up to 30 MeV. The obtained results have been compared with each other and available experimental data existing in the EXFOR database. Generally, at least one level density model cross-section calculations are in agreement with the experimental results for all reactions except {sup 144}Sm(γ, 2n){sup 142}Sm along the incident photon energy, TALYS 1.6 BSFM option for the level density model cross-section calculations can be chosen if the experimental data are not available or are improbable to be produced due to the experimental difficulty.

  15. Experimental cross-sections of deuteron-induced reaction on 89Y up to 20 MeV; comparison of natTi(d,x)48V and 27Al(d,x)24Na monitor reactions

    NASA Astrophysics Data System (ADS)

    Lebeda, Ondřej; Štursa, Jan; Ráliš, Jan

    2015-10-01

    We measured cross-sections of the deuteron-induced reactions on 89Y in the energy range of 3.9-19.5 MeV. Excitation functions for formation of 88Zr, 89mZr, 89Zr, 88Y, 90mY and 87mSr were determined and compared with previously published data and prediction of the TALYS code. Thick target yields for production of 88Zr, 89Zrcum, 88Y, 90mY and 87mSr were calculated from the measured cross-sections. Achievable activity versus radionuclidic purity of medically relevant 89Zr is discussed and compared with the production via the 89Y(p,n) reaction. Parallel use of titanium and aluminium beam monitors revealed systematic difference between the recommended cross-sections of both monitoring reactions and provided new cross-section data for formation of 24Na, 27Mg, 43Sc, 44mSc, 44Sc, 46Sc, 47Sc and 48Sc. The cross-sections for the natTi(d,x)46Sc reactions agree very well with recently proposed recommended values.

  16. How Accurately Do We Know the Cross Section of the 7Be(p, {gamma})8B Reaction?

    SciTech Connect

    Gai, Moshe

    2006-03-13

    The 'world average' of the astrophysical cross section factor , S17(0), is driven by the Seattle result due to the very small quoted uncertainty, which we however demonstrate it to be an overestimated accuracy. We propose more realistic error bars for the Seattle results based on the published Seattle data. This leads to a an uncertainty of the measured slope of S17 and thus an uncertainty due to extrapolation that can be reasonably estimated to be {sub -3.0}{sup +0.0} eV-b.

  17. Experimental cross section of the 71Ga(n,γ)72Ga reaction at 0.0334 eV energy

    NASA Astrophysics Data System (ADS)

    Afroze, N.; Uddin, M. S.; Hossain, S. M.; Islam, M. A.; Shariff, M. A.; Zakaria, A. K. M.; Datta, T. K.; Azharul Islam, S. M.

    2014-10-01

    The cross section of the 71Ga(n,γ)72Ga reaction at 0.0334 eV was measured for the first time using monochromatic neutrons from powder diffractometer at TRIGA Mark II nuclear reactor. The 197Au(n,γ)198Au reaction was used to monitor the neutron beam intensity. The HPGe γ-ray spectrometry was used to determine the radioactivity of the product radionuclides. The obtained cross section value amounted 3.42 ± 0.27 b is about 95% consistent with JENDL-4, but about 17% and 14% lower than that of the ENDF/B-VII and TENDL-2012 data libraries, respectively. The measured value at 0.0334 eV and the previous measured value at 0.0536 eV would be useful to confirm the reliability of the data evaluated by 1/v relation in the above libraries.

  18. Measurement of cross sections for the 147Sm(n, alpha)144Nd reaction at 5.0 and 6.0 MeV.

    PubMed

    Zhang, Guohui; Zhang, Jiaguo; Guo, Li'an; Wu, Hao; Chen, Jinxiang; Tang, Guoyou; Gledenov, Yu M; Sedysheva, M V; Khuukhenkhuu, G; Szalanski, P J

    2009-01-01

    Cross sections of the (147)Sm(n, alpha)(144)Nd reaction were measured at En=5.0 and 6.0MeV. A twin gridded ionization chamber was used as a charged particle detector and two large area (147)Sm(2)O(3) samples placed back to back were employed. Experiments were performed at the 4.5MV Van de Graaff accelerator of Peking University. Neutrons were produced through the D(d, n)(3)He reaction with a deuterium gas target. Absolute neutron flux was determined by a small (238)U fission chamber. Present cross-section data are compared with existing results of evaluations and measurements. PMID:18707895

  19. Total cross section of the 3H(p,n)3He reaction from threshold to 4.5 MeV

    NASA Astrophysics Data System (ADS)

    Brune, C. R.; Hahn, K. I.; Kavanagh, R. W.; Wrean, P. R.

    1999-07-01

    We report new measurements of the total cross section for the 3H(p,n)3He reaction from threshold (Ep=1.02 MeV) to Ep=4.5 MeV. The experiment utilized specially prepared Ti-3H targets, and neutrons were detected using a 4π detector. A weak resonant structure due to an excited state in 4He is observed which was not seen in previous cross section measurements. A new expression for the 3He(n,p)3H thermonuclear reaction rate for temperatures below 10 GK is presented which will allow for more accurate calculations of the yields of light elements produced by big-bang nucleosynthesis.

  20. Cross-Section Measurement of the 169Tm(n,3n)167Tm Reaction and Constraining the Branching Ratio of 167Tm

    NASA Astrophysics Data System (ADS)

    Champine, Brian; Gooden, Matthew; Thomas, Keenan; Krishichayan, F.; Norman, Eric; Scielzo, Nick; Tonchev, Anton; Tornow, Werner

    2015-10-01

    The cross section of the 169Tm(n,3n)167Tm reaction has been measured from 17.5 to 21.5 MeV using activation technique. This energy region was chosen to resolve the two different trends of the previous (n,3n) cross section measurements on 169Tm. In addition, the branching ratio of the 207.8 keV γ-ray line stemming from electron capture of 167Tm was measured to be 0.419(16). The result of these measurements provide more accurate diagnostic estimation of the so called reaction-in-flight neutrons produced via the internal confinement fusion plasma in deuterium-tritium capsules at the National Ignition Facility.

  1. Spallation reaction study for fission products in nuclear waste: Cross section measurements for 137Cs and 90Sr on proton and deuteron

    NASA Astrophysics Data System (ADS)

    Wang, H.; Otsu, H.; Sakurai, H.; Ahn, D. S.; Aikawa, M.; Doornenbal, P.; Fukuda, N.; Isobe, T.; Kawakami, S.; Koyama, S.; Kubo, T.; Kubono, S.; Lorusso, G.; Maeda, Y.; Makinaga, A.; Momiyama, S.; Nakano, K.; Niikura, M.; Shiga, Y.; Söderström, P.-A.; Suzuki, H.; Takeda, H.; Takeuchi, S.; Taniuchi, R.; Watanabe, Ya.; Watanabe, Yu.; Yamasaki, H.; Yoshida, K.

    2016-03-01

    We have studied spallation reactions for the fission products 137Cs and 90Sr for the purpose of nuclear waste transmutation. The spallation cross sections on the proton and deuteron were obtained in inverse kinematics for the first time using secondary beams of 137Cs and 90Sr at 185 MeV/nucleon at the RIKEN Radioactive Isotope Beam Factory. The target dependence has been investigated systematically, and the cross-section differences between the proton and deuteron are found to be larger for lighter spallation products. The experimental data are compared with the PHITS calculation, which includes cascade and evaporation processes. Our results suggest that both proton- and deuteron-induced spallation reactions are promising mechanisms for the transmutation of radioactive fission products.

  2. Isotopic production cross sections and recoil velocities of spallation-fission fragments in the reaction {sup 238}U(1A GeV)+d

    SciTech Connect

    Pereira, J.; Benlliure, J.; Casarejos, E.; Armbruster, P.; Enqvist, T.; Schmidt, K.-H.; Bernas, M.; Mustapha, B.; Rejmund, F.; Stephan, C.; Taieeb, J.; Tassan-Got, L.; Boudard, A.; Legrain, R.; Leray, S.; Volant, C.; Wlazlo, W.

    2007-01-15

    Fission fragments of 1A GeV{sup 238}U nuclei interacting with a deuterium target have been investigated with the Fragment Separator (FRS) at Gesellschaft fuer Schwerionenforschung (GSI) by measuring their isotopic production cross sections and velocities. Results, along with those obtained recently for spallation-evaporation fragments, provide a comprehensive analysis of the spallation nuclear productions in this reaction. Details about the experimental performance, data reduction and results are presented.

  3. OPPORTUNITIES TO CONSTRAIN ASTROPHYSICAL REACTION RATES FOR THE s-PROCESS VIA DETERMINATION OF THE GROUND-STATE CROSS-SECTIONS

    SciTech Connect

    Rauscher, T.; Mohr, P.; Dillmann, I.; Plag, R.

    2011-09-10

    Modern models of s-process nucleosynthesis in stars require stellar reaction rates of high precision. Most neutron-capture cross-sections in the s-process have been measured, and for an increasing number of reactions the required precision is achieved. This does not necessarily mean, however, that the stellar rates are constrained equally well, because only the capture of the ground state of a target is measured in the laboratory. Captures of excited states can contribute considerably to stellar rates that are already at typical s-process temperatures. We show that the ground-state contribution X to a stellar rate is the relevant measure to identify reactions that are or could be well constrained by experiments and apply it to (n,{gamma}) reactions in the s-process. We further show that the maximum possible reduction in uncertainty of a rate via determination of the ground-state cross-section is given directly by X. An error analysis of X is presented, and it is found that X is a robust measure with mostly small uncertainties. Several specific examples (neutron capture of {sup 79}Se, {sup 95}Zr, {sup 121}Sn, {sup 187}Os, and {sup 193}Pt) are discussed in detail. The ground-state contributions for a set of 412 neutron-capture reactions around the s-process path are presented in a table. This allows identification of reactions that may be better constrained by experiments and that cannot be constrained solely by measuring ground-state cross-sections (and thus require supplementary studies). General trends and implications are discussed.

  4. Cross section limits for the {sup 248}Cm({sup 25}Mg,4n-5n){sup 268,269}Hs reactions

    SciTech Connect

    Dvorak, J.; Dvorakova, Z.; Schuber, R.; Tuerler, A.; Yakushev, A.; Bruechle, W.; Duellmann, Ch. E.; Jaeger, E.; Schaedel, M.; Schausten, B.; Schimpf, E.; Eberhardt, K.; Thoerle, P.; Eichler, R.; Nagame, Y.; Qin, Z.; Semchenkov, A.; Wegrzecki, M.

    2009-03-15

    We report on an attempt to produce and detect {sup 268}Hs and {sup 269}Hs in the nuclear fusion reaction {sup 25}Mg+{sup 248}Cm using the gas phase chemistry apparatus COMPACT. No decay chains attributable to the decay of hassium isotopes were observed during the course of this experiment. From the nonobservation of {sup 269}Hs we derive a cross section limit of 0.4 pb (63% confidence limit) for the reaction {sup 248}Cm({sup 25}Mg,4n){sup 269}Hs at a center-of-target beam energy of 140 MeV. The evaluated cross section limit for the {sup 248}Cm({sup 25}Mg,5n){sup 268}Hs reaction depends on the assumed half-life of unknown {sup 268}Hs. Current systematics of the half-lives for even-even Hs isotopes suggests a value of 0.5 s, resulting in a cross section limit of 1.3 pb.

  5. Cross section measurement for the (95)Mo(n, alpha)(92)Zr reaction at 4.0, 5.0 and 6.0MeV.

    PubMed

    Zhang, Guohui; Wu, Hao; Zhang, Jiaguo; Liu, Jiaming; Yin, Yuxiang; Chen, Jinxiang; Gledenov, Yu M; Sedysheva, M V; Khuukhenkhuu, G; Koehler, P E; Szalanski, P J

    2010-01-01

    Measurements of cross sections of the (95)Mo(n, alpha)(92)Zr reaction at E(n)=4.0, 5.0 and 6.0MeV were carried out at the 4.5MV Van de Graaff of Peking University, China. A twin gridded ionization chamber and two large-area (95)Mo samples were adopted. Fast neutrons were produced through the D(d, n)(3)He reaction by using a deuterium gas target. A small (238)U fission chamber was employed for absolute neutron flux determination. Present data are compared with existing evaluations and measurement. PMID:19811925

  6. Direct measurement of the (23)Na(α,p)(26)Mg reaction cross section at energies relevant for the production of galactic (26)Al.

    PubMed

    Almaraz-Calderon, S; Bertone, P F; Alcorta, M; Albers, M; Deibel, C M; Hoffman, C R; Jiang, C L; Marley, S T; Rehm, K E; Ugalde, C

    2014-04-18

    The 1809-keV γ ray from the decay of (26)Al(g) is an important target for γ-ray astronomy. In the convective C/Ne burning shell of massive presupernova stars, the (23)Na(α,p)(26)Mg reaction directly influences the production of (26)Al. We have performed a direct measurement of the (23)Na(α,p)(26)Mg reaction cross section at the appropriate astrophysically important energies. The stellar rate calculated in the present work is larger than the recommended rate by nearly a factor of 40 and could strongly affect the production of (26)Al in massive stars. PMID:24785033

  7. Dynamics of alkali ions-neutral molecules reactions: Radio frequency-guided beam experimental cross-sections and direct quasiclassical trajectory studies

    SciTech Connect

    Aguilar, J.; Andres, J. de; Lucas, J. M.; Alberti, M.; Huarte-Larranaga, F.; Bassi, D.; Aguilar, A.

    2012-11-27

    Different reactive processes taking place in collisions between alkali ions and neutral i-C{sub 3}H{sub 7}Cl molecules in the low (center of mass frame) energy range have been studied using an octopole radiofrequency guided-ion-beam apparatus developed in our laboratory. Cross-section energy dependences for all these reactions have been obtained in absolute units. Ab initio electronic structure calculations for those colliding systems evolving on the ground single potential surface have given relevant information on the main topological features of the surfaces. For some of the reactions a dynamic study by 'on the fly' trajectories has complemented the available experimental and electronic structure information.

  8. Cross sections of the 57Fe(n,α)54Cr and 63Cu(n,α)60Co reactions in the MeV region

    NASA Astrophysics Data System (ADS)

    Gledenov, Yu. M.; Sedysheva, M. V.; Stolupin, V. A.; Zhang, Guohui; Han, Jinhua; Wang, Zhimin; Fan, Xiao; Liu, Xiang; Chen, Jinxiang; Khuukhenkhuu, G.; Szalanski, P. J.

    2014-06-01

    Cross sections of the 57Fe(n,α)54Cr reaction are measured for the first time, and those of the 63Cu(n,α)60Co reaction are measured in the megaelectron volt region by the direct experimental method. Experiments were performed at the 4.5-MV Van de Graaff Accelerator of Peking University. Monoenergetic neutrons (5.0, 5.5, 6.0, and 6.5 MeV) were produced through the 2H(d,n)3He reaction with a deuterium gas target. Measurements were carried out using a double-section-gridded ionization chamber and back-to-back double 57Fe and 63Cu samples. Foreground and background were measured in separate runs. A 238U sample and a BF3 long counter were utilized for absolute neutron flux calibration and for neutron flux normalization, respectively. Present results are compared with talys-1.4 code predictions, existing measurements, and evaluations.

  9. Benchmark experiment for the cross section of the 100Mo(p,2n)99mTc and 100Mo(p,pn)99Mo reactions

    NASA Astrophysics Data System (ADS)

    Takács, S.; Ditrói, F.; Aikawa, M.; Haba, H.; Otuka, N.

    2016-05-01

    As nuclear medicine community has shown an increasing interest in accelerator produced 99mTc radionuclide, the possible alternative direct production routes for producing 99mTc were investigated intensively. One of these accelerator production routes is based on the 100Mo(p,2n)99mTc reaction. The cross section of this nuclear reaction was studied by several laboratories earlier but the available data-sets are not in good agreement. For large scale accelerator production of 99mTc based on the 100Mo(p,2n)99mTc reaction, a well-defined excitation function is required to optimise the production process effectively. One of our recent publications pointed out that most of the available experimental excitation functions for the 100Mo(p,2n)99mTc reaction have the same general shape while their amplitudes are different. To confirm the proper amplitude of the excitation function, results of three independent experiments were presented (Takács et al., 2015). In this work we present results of a thick target count rate measurement of the Eγ = 140.5 keV gamma-line from molybdenum irradiated by Ep = 17.9 MeV proton beam, as an integral benchmark experiment, to prove the cross section data reported for the 100Mo(p,2n)99mTc and 100Mo(p,pn)99Mo reactions in Takács et al. (2015).

  10. Systematics Studies of the Production Cross Sections of (n,tritium) Reaction Via 14.5 MeV Neutrons

    SciTech Connect

    Belgaid, M.; Kadem, F.; Asghar, M

    2005-07-15

    A new semi-empirical formula with five parameters has been derived to systematize the (n,t) cross section data of 14.5MeV neutrons. It is based on the evaporation model and uses the droplet model of Myers and Swiatecki to express the Q{sub (n,t)}. The behavior of the different terms of the droplet model involved in Q{sub (n,t)} was checked individually before choosing the pertinent terms and setting up the formula. This relation leads to the lowest value of {chi}{sup 2} compared with the existing formulae, when used to correlate the experimental {sigma}{sub (n,t)} data for 25 nuclei.

  11. Experimental cross-sections for proton induced nuclear reactions on mercury up to 65 MeV

    NASA Astrophysics Data System (ADS)

    Hermanne, A.; Tárkányi, F.; Takács, S.; Ditrói, F.; Szücs, Z.; Brezovcsik, K.

    2016-07-01

    Cross-sections for formation of activation products induced by protons on natural mercury targets were measured. Results for 196m,196g,197g(cum), 198m,198g,199g(cum), 200g(cum), 201,202Tl, 194g(cum), 195g(cum), 196g(cum), 198m,199g(cum) Au and 195m,197m,203Hg are presented up to 65 MeV incident particle energy, many of these for the first time. The experimental data are compared with literature values and with the predictions of the TALYS 1.6 code (results taken from TENDL-2015 on-line library), thick target yields were derived and possible applications in biomedical sciences are discussed.

  12. Thermal Cross Sections and Resonance Integrals for Ag{sup 109}(n,{gamma})Ag{sup 110m} and Several Other Reactions

    SciTech Connect

    Williams, J.G.

    2011-07-01

    In this paper measurements reported from the Rikkyo Research Reactor are reanalysed using a least squares adjustment procedure in which the adjustable parameters were the thermal and epithermal neutron fluences, the epithermal shape parameter and the thermal neutron cross sections and resonance integrals of all the dosimeters, including the gold and cobalt standards. The methodology and the results are described. Nuclear data including cross sections, recommended in ASTM Standard Test Method E 481, for the {sup 59}Co(n,{gamma}){sup 60}Co and Ag{sup 109}(n,{gamma})Ag{sup 110m} reactions were changed in a recent revision of the standard. The change for the silver thermal neutron cross section was very large compared to the previously cited uncertainties. The reference cited in the standard is the only new measurement that has been reported in many years. The value reported there for the 2200 m/s cross section is 4.12 {+-} 0.10 barn. This reevaluation adjusts that value to 3.87 {+-} 0.08 barn. The value in the previous edition of E481, however, was 4.7 barns {+-} 4%. Such a large change greatly affects the neutron fluence values that will be calculated. (author)

  13. Radar cross section of insects

    NASA Astrophysics Data System (ADS)

    Riley, J. R.

    1985-02-01

    X-band measurements of radar cross section as a function of the angle between insect body axis and the plane of polarization are presented. A finding of particular interest is that in larger insects, maximum cross section occurs when the E-vector is perpendicular to the body axis. A new range of measurements on small insects (aphids, and planthoppers) is also described, and a comprehensive summary of insect cross-section data at X-band is given.

  14. Testing the predictive power of statistical model calculations of the (a,g) reaction cross-sections for the p-process

    NASA Astrophysics Data System (ADS)

    Murphy, Brendan; Simon, Anna

    2015-10-01

    p-process nucleosynthesis is believed to be the origin of 35 stable, proton-rich nuclei called ``p-nuclei'', that cannot be synthesized by neutron captures. The complex p-process network includes, among others, (α , γ) reactions, whose cross-sections are not very well described by current theoretical models. Here, a collection of experimentally measured (α , γ) reactions from the KADoNiS-p database was used as a test for various models obtained from TALYS, a nuclear reaction program, and NON-SMOKER, the principal theoretical database in this field. Statistical models in this investigation required the alpha optical model potential (aOMP), the gamma strength function (gSF), and the level density model (ld) as input. Permutations of all three were used in theoretical calculations; as there exist 5 separate models for aOMP and gSF, and 6 for ld, there were 150 combinations of interest. After calculating cross-sections with these parameters, a χ2 test was used to determine the set of permutes that was closest to the experimental data. The (α , γ) reaction of the 91Zr target is presented as the example case.

  15. Elastic Differential Cross Sections

    NASA Technical Reports Server (NTRS)

    Werneth, Charles M.; Maung, Khin M.; Ford, William P.; Norbury, John W.; Vera, Michael D.

    2014-01-01

    The eikonal, partial wave (PW) Lippmann-Schwinger, and three-dimensional Lippmann-Schwinger (LS3D) methods are compared for nuclear reactions that are relevant for space radiation applications. Numerical convergence of the eikonal method is readily achieved when exact formulas of the optical potential are used for light nuclei (A less than or equal to 16) and the momentum-space optical potential is used for heavier nuclei. The PW solution method is known to be numerically unstable for systems that require a large number of partial waves, and, as a result, the LS3D method is employed. The effect of relativistic kinematics is studied with the PW and LS3D methods and is compared to eikonal results. It is recommended that the LS3D method be used for high energy nucleon- nucleus reactions and nucleus-nucleus reactions at all energies because of its rapid numerical convergence and stability.

  16. Cross sections of the 56Fe(n ,α ) 53Cr and 54Fe(n ,α ) 51Cr reactions in the MeV region

    NASA Astrophysics Data System (ADS)

    Wang, Zhimin; Fan, Xiao; Zhang, Luyu; Bai, Huaiyong; Chen, Jinxiang; Zhang, Guohui; Gledenov, Yu. M.; Sedysheva, M. V.; Krupa, L.; Khuukhenkhuu, G.

    2015-10-01

    Cross sections of the 56Fe(n ,α ) 53Cr and 54Fe(n ,α )51Cr reactions were measured at En=5.5 and 6.5 MeV and En=4.0 ,4.5 ,5.5 ,and 6.5 MeV , respectively, using a double-section gridded ionization chamber as the α -particle detector. Natural iron and enriched 56Fe and 54Fe foil samples were prepared. A deuterium gas target was used to produce monoenergetic neutrons through the 2H(d ,n )3He reaction. Two rounds of experiments were performed at the 4.5-MV Van de Graaff Accelerator of Peking University. The foreground and background were measured in separate runs. The neutron flux was monitored by a B F3 long counter, and the cross sections of the 238U(n ,f ) reaction were used as the standard. Present results are compared with those of the talys-1.6 code calculations, existing measurements, and evaluations.

  17. Improved cross section calculations for astrophysical applications

    NASA Technical Reports Server (NTRS)

    Silberberg, R.; Tsao, C. H.; Letaw, J. R.

    1985-01-01

    Modifications are proposed for the semiempirical equations and parameters of Silberberg and Tsao (1973) for partial cross section calculations of proton-nucleus reactions in cosmic rays. These modifications include: adjustment of general parameters; modification of energy dependence; effects of nuclear alpha-particle structure, deuteron emission, and even-charged products; peripheral reactions; fission reactions; averaging cross sections near boundaries of different parameters; elimination of certain special cases; and treatment of the Pt to Pb group that cannot yet be generalized to Z(t) less than 76.

  18. Photonuclear absorption cross sections

    NASA Technical Reports Server (NTRS)

    Norbury, John W.

    1989-01-01

    Neutron multiplicity in photonuclear reactions; invariance of classical electromagnetism; momentum transfer models in ion collisions; cosmic ray electromagnetic interactions; quadrupole excitations in nucleus-nucleus collisons and Y-89 interactions with relativistic nuclei; and the Weizsacker-Williams theory for nucleon emission via electromagnetic excitations in nucleus-nucleus collisions are discussed.

  19. Production cross sections of elements near the N=126 shell in Ca48-induced reactions with Gd154,Tb159,Dy162, and Ho165 targets

    NASA Astrophysics Data System (ADS)

    Mayorov, D. A.; Werke, T. A.; Alfonso, M. C.; Bennett, M. E.; Folden, C. M.

    2014-08-01

    Excitation functions for shell-stabilized evaporation residues produced in Ca48-induced reactions with Gd154,Tb159,Dy162, and Ho165 targets have been measured in experiments performed at the Cyclotron Institute at Texas A&M University. The examined energy range predominantly covers the 3n and 4n evaporation channels with higher cross sections measured for the 4n products. The σ4n are nearly invariant within experimental uncertainty in reactions with Tb159,Dy162, and Ho165 with the maxima at 12.6 ± 1.9, 12.6 ± 1.7, and 9.4 ± 1.3 mb, respectively. For the reaction with Gd154, the maximum is slightly lower at 4.0 ± 0.6 mb. A simple model to describe the measured production cross sections was employed. Capture was estimated by using the "diffused barrier formula" from the "fusion by diffusion" model proposed by Świątecki et al. [Phys. Rev. C 71, 014602 (2005)]., 10.1103/PhysRevC.71.014602 The fusion probability was estimated by using a phenomenological expression presented by Siwek-Wilczyńska et al. [Int. J. Mod. Phys. E 17, 12 (2008)]., 10.1142/S0218301308009501 The survival probability was calculated according to the formula of Vandenbosch and Huizenga [Nuclear Fission (Academic, New York, 1973)], derived from transition-state theory. The best agreement is reached between calculation and experiment upon inclusion of collective effects in the calculation of the survival probability, shown previously to be important for production of weakly deformed nuclei. This, in turn, challenges the expectation that strong shell stabilization benefits the production cross section. The present data are compared with earlier studies on production of neutron-deficient nuclei in Ca-induced reactions with lanthanide targets.

  20. Differential cross sections measurement of 28Si(p,p/γ)28Si and 29Si(p,p/γ)29Si reactions for PIGE applications

    NASA Astrophysics Data System (ADS)

    Jokar, A.; Kakuee, O.; Lamehi-Rachti, M.

    2016-03-01

    Differential cross sections for gamma-ray emission from the 28Si(p,p/γ)28Si (Eγ = 1779 keV) and the 29Si(p,p/γ)29Si (Eγ = 1273 keV) nuclear reactions were measured in the energy range of 2.0-3.2 MeV and 2.0-3.0 MeV, respectively. The thin Si targets were prepared by evaporating natural SiO onto self-supporting Ag films. The gamma-rays and backscattered protons were detected simultaneously. An HPGe detector placed at an angle of 90° with respect to beam direction was employed to collect gamma-rays while an ion implanted Si detector placed at a scattering angle of 165° was used to detect backscattered protons. The great advantage of this work is that differential cross sections were obtained with a procedure irrespective of absolute value of the collected beam charge.

  1. Quasi elastic cross sections for the Bi-209(e, e-prime p) Pb-208 reaction: Jefferson Lab experiment E06007

    SciTech Connect

    J.C. Cornejo, J.L. Herraiz, A. Camsonne, A. Saha, J.M. Udias, G. Urciuoli, J.R. Vignote, K.A. Aniol

    2012-09-01

    Quasi elastic cross sections were measured for the first time for both negative and positive missing momenta for the {sup 209}Bi(e,e'p){sup 208}Pb reaction leading to the ground state and hole states of (208)Pb. Experimental cross sections obtained between -0.3 GeV/c to 0.3 GeV/c agree with theoretical calculations using RDWIA techniques both in shape and magnitude for the ground state. The data for the ground state production of {sup 208}Pb are consistent with a theoretical model assuming a single proton(1.06 +- 0.10) in the 1h9/2 orbit in {sup 209}Bi.

  2. Measurement of the /sup 12/C(/sup 3/He, /pi//sup +/)/sup 15/N reaction cross section near threshold

    SciTech Connect

    Homolka, J.; Schott, W.; Wagner, W.; Wilhelm, W.; Bent, R.D.; Fatyga, M.; Pollock, R.E.; Saber, M.; Segel, R.E.; Kienle, P.

    1988-12-01

    The pionic fusion reaction /sup 12/C(/sup 3/He,/pi//sup +/)/sup 15/N has been measured at 170.2 and 236.3 MeV bombarding energy using recoil detection. At T/sub <3/He$ = 170.2 MeV the angle-integrated cross section for the population of both the /sup 15/N/sub g.s./ and a broad group of unresolved /sup 15/N excited states between E/sub x/ = 6 and 10 MeV is less than 0.03 nb. At T/sub <3/He$ = 236.3 MeV the total cross section summed over both groups is (0.8 +- 0.2) nb.

  3. Photodisintegration cross section of the reaction (4)He(γ,p)(3)H between 22 and 30 MeV.

    PubMed

    Raut, R; Tornow, W; Ahmed, M W; Crowell, A S; Kelley, J H; Rusev, G; Stave, S C; Tonchev, A P

    2012-01-27

    The two-body photodisintegration cross section of (4)He into a proton and triton was measured with monoenergetic photon beams in 0.5 MeV energy steps between 22 and 30 MeV. High-pressure (4)He-Xe gas scintillators of various (4)He/Xe ratios served as targets and detectors. Pure Xe gas scintillators were used for background studies. A NaI detector together with a plastic scintillator paddle was employed for determining the incident photon flux. Our comprehensive data set follows the trend of the theoretical calculations of the Trento group very well, although our data are consistently lower in magnitude by about 5%. However, they differ significantly from the majority of the previous data, especially from the recent data of Shima et al. The latter data had put into question the validity of theoretical approaches used to calculate core-collapse supernova explosions and big-bang nucleosynthesis abundances of certain light nuclei. PMID:22400829

  4. MODELING AND FISSION CROSS SECTIONS FOR AMERICIUM.

    SciTech Connect

    ROCHMAN, D.; HERMAN, M.; OBLOZINSKY, P.

    2005-05-01

    This is the final report of the work performed under the LANL contract on the modeling and fission cross section for americium isotopes (May 2004-June 2005). The purpose of the contract was to provide fission cross sections for americium isotopes with the nuclear reaction model code EMPIRE 2.19. The following work was performed: (1) Fission calculations capability suitable for americium was implemented to the EMPIRE-2.19 code. (2) Calculations of neutron-induced fission cross sections for {sup 239}Am to {sup 244g}Am were performed with EMPIRE-2.19 for energies up to 20 MeV. For the neutron-induced reaction of {sup 240}Am, fission cross sections were predicted and uncertainties were assessed. (3) Set of fission barrier heights for each americium isotopes was chosen so that the new calculations fit the experimental data and follow the systematics found in the literature.

  5. XCOM: Photon Cross Sections Database

    National Institute of Standards and Technology Data Gateway

    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.

  6. The total charm cross section

    SciTech Connect

    Vogt, R

    2007-09-14

    We assess the theoretical uncertainties on the total charm cross section. We discuss the importance of the quark mass, the scale choice and the parton densities on the estimate of the uncertainty. We conclude that the uncertainty on the total charm cross section is difficult to quantify.

  7. Analysis of cross sections using various nuclear potential

    SciTech Connect

    Aziz, Azni Abdul; Kassim, Hasan Abu; Yusof, Norhasliza; Muhammad Zamrun, F.

    2014-05-02

    The relevant astrophysical reaction rates which are derived from the reaction cross sections are necessary input to the reaction network. In this work, we analyse several theoretical models of the nuclear potential which give better prediction of the cross sections for some selected reactions.

  8. From γ emissions to (n,xn) cross sections of interest: The role of GAINS and GRAPhEME in nuclear reaction modeling

    NASA Astrophysics Data System (ADS)

    Kerveno, M.; Bacquias, A.; Borcea, C.; Dessagne, Ph.; Henning, G.; Mihailescu, L. C.; Negret, A.; Nyman, M.; Olacel, A.; Plompen, A. J. M.; Rouki, C.; Rudolf, G.; Thiry, J. C.

    2015-12-01

    During the last 10 years, in the general context of nuclear energy applications and future reactors development, our collaboration has performed measurements of (n, x nγ cross sections to study (n, xn) reactions. Large sets of new and accurate experimental data have been produced on a variety of nuclei from 7Li to 238U. Comparisons with nuclear reaction code calculations have shown that the predictions of these exclusive cross sections are a real challenge for the theoretical codes. Indeed many processes are involved as evaporation, fission if fissionable nucleus, direct and pre-equilibrium reactions, etc. All these processes should be simultaneously well described by the models that using nuclear structure description for optical potential, level densities, decay scheme, etc. In this article, we review what we have learned since the last P(ND)2 workshop held in 2005 (A.J.M. Plompen, Proceedings of the Perspectives on Nuclear data for the Next Decade Workshop, Bruyères-le-Châtel, France, 26-28 September 2005, NEA Report N° 6121, p. 151) and highlight how we can further progress in this field in order to provide new, complete, accurate and relevant experimental data.

  9. Cross sections of the {sup 67}Zn(n,{alpha}){sup 64}Ni reaction at 4.0, 5.0, and 6.0 MeV

    SciTech Connect

    Zhang Guohui; Liu Jiaming; Wu Hao; Liu Xiang; Chen Jinxiang; Gledenov, Yu. M.; Sedysheva, M. V.; Stolupin, V. A.; Khuukhenkhuu, G.; Szalanski, P. J.

    2010-11-15

    Experimental cross section data of the {sup 67}Zn(n,{alpha}){sup 64}Ni reaction are very scanty because the residual nucleus {sup 64}Ni is stable and the commonly used activation method is not feasible. As a result, very large deviations (about 10 times) exist among different nuclear data libraries. In the present work, cross sections of the partial {sup 67}Zn(n,{alpha}{sub 0}){sup 64}Ni and total {sup 67}Zn(n,{alpha}){sup 64}Ni reactions are measured at neutron energies of 4.0 and 5.0 MeV for the first time, and those of 6.0 MeV are remeasured for consistency checking. A twin-gridded ionization chamber was used as the charged-particle detector and two enriched back-to-back-set {sup 67}Zn samples were adopted. Experiments were performed at the 4.5 MV Van de Graaff Accelerator of Peking University. Neutrons were produced through the {sup 2}H(d,n){sup 3}He reaction using a deuterium gas target. Absolute neutron flux was determined by counting the fission fragments from a {sup 238}U sample placed inside the gridded ionization chamber while a BF{sub 3} long counter was employed as neutron flux monitor. Present data are compared with results of previous measurements, evaluations, and talys code calculations.

  10. Cross Section Measurement for the 95Mo(n, {alpha})92Zr Reaction at 4.0, 5.0 and 6.0 MeV

    SciTech Connect

    Zhang, Guohui; Wu, Hao; Zhang, Jiaguo; Liu, Jiaming; Yin, Yuxiang; Chen, Jinxiang; Gledenov, Youri Mikhailovich; Sedysheva, M. V.; Khuukhenkhuu, G; Koehler, Paul Edward; Szalanski, P.

    2011-01-01

    For the {sup 95}Mo(n, {alpha}){sup 92}Zr reaction cross section, there is only one experimental datum in the MeV neutron energy region with large uncertainty. As a result, very large deviations exist in different evaluated nuclear data libraries. This paper report the measurement of cross sections of the {sup 95}Mo(n, {alpha}){sup 92}Zr reaction at En = 4.0, 5.0 and 6.0 MeV. Experiments were performed at the 4.5 MV Van de Graaff of Peking University, China. A twin gridded ionization chamber was used as alpha particle detector and two large area {sup 95}Mo samples placed back to back were adopted. Fast neutrons were produced through the D(d, n){sup 3}He reaction by using a deuterium gas target. A small {sup 238}U fission chamber was adopted for absolute neutron flux determination and a BF{sub 3} long counter was used for neutron flux monitor. Present experimental data are compared with existing evaluations and measurement.

  11. Cross-section measurement of the 18F(alpha,p)21Ne reaction and possible implication for neutron production in explosive helium burning

    SciTech Connect

    Couture, Aaron Joseph; Lee, Hye Young; Couder, Manoel; Falahat, Sascha; Gorres, Joachim; Lamm, Larry O; Le Blanc, P J; O' Brien, Shawn P; Palumbo, Annalia; Stech, Edward J; Strandberg, Elizabeth; Tan, Wanpeng; Ugalde, Claudio; Wiescher, Michael C. F.

    2009-01-01

    At the high temperature and density conditions of hot or explosive helium burning, the {sup 18}F({alpha},p){sup 21}Ne reaction may compete successfully wilh the {sup 18}F({beta}{sup +}{nu}) decay. This suggesls {sup 21}Ne({alpha},n) as an alternative neutron source in Ihe r-process. We have determined the total cross section of the {sup 18}F({alpha},p){sup 21}Ne reaction by studying the time-reverse reaction {sup 21}Ne(p,{alpha}){sup 18}F. Using the activation technique, the total reaction yield was measured in the proton beam energy range of 2.3-4.0 MeV, which corresponds to energies of 0.5-2.1 MeV in the {sup 18}F + {alpha} system. The resulting yield curve was analyzed in terms of the thick target formalism and the R-matrix theory. The reaction rate was deduced experimentally for the first time for the temperature of 0.1 < T{sub 9} < I. The experimemal reaction rate was compared with Hauser-Feshbach predictions. The astrophysical implications of the new rate are discussed.

  12. Quantum wavepacket dynamics of the N(4 S) + NO(X2 Π) reaction and its isotopic variants: Integral cross sections and thermal rate constants

    NASA Astrophysics Data System (ADS)

    Manivannan, V.; Padmanaban, R.

    2016-08-01

    We investigate the initial state-selected dynamics of the title reaction on its ground (1 3A″) and first excited (1 3A‧) triplet potential energy surfaces (PESs) by a time-dependent wavepacket propagation method, employing the ab initio analytical PESs developed by Gamallo et al. (2003). All partial wave contributions up to the total angular momentum J = 140 are found to be necessary for the scattering of NO diatom in its vibrational and rotational ground state up to a collision energy ∼ 0.9 eV. The converged initial state-selected reaction attributes viz., reaction probabilities, integral cross sections and thermal rate constants are obtained within the centrifugal sudden (CS) approximation and the convergence of the results are carefully checked by varying all parameters used in the numerical calculations. The dynamical results are compared with the other reported theoretical and experimental findings. Investigation on the energy-resolved channel-specific reaction probabilities infers that the N2 formation channel is very much favorable than the N-exchange channel. The reaction proceeds via some metastable resonances, observed from the oscillatory probability curves, which is more in the latter channel compared to the former. The effect of rotational and vibrational excitations of the reagent (NO diatom) on the dynamics is examined. We also examine the effect of isotopic substitution of N-atom (14 N by 15 N) on the reaction dynamics.

  13. Non-coplanar compact configurations of nuclei and non-compound-nucleus contribution in the fusion cross section of the 12C+93Nb reaction

    NASA Astrophysics Data System (ADS)

    Chopra, Sahila; Hemdeep, Kaur, Arshdeep; Gupta, Raj K.

    2016-02-01

    Background: In our earlier study of the 12C+93Nb→*105Ag reaction at three near- and below-barrier energies (Ec .m .=41.097 , 47.828, and 54.205 MeV), using the dynamical cluster-decay model (DCM) with various nuclear interaction potentials (the Blocki et al. pocket formula and others derived from the Skyrme energy density formalism) for compact, coplanar (Φc=00 ) nuclei, we found a large non-compound-nucleus (nCN) contribution in the measured fusion cross section of this reaction. Purpose: In the present work, we look for the effect of using non-coplanar, compact configurations (Φc≠00 ), in the Blocki et al. pocket formula of the nuclear proximity potential, on the non-compound-nucleus (nCN) contribution, using the DCM. Methods: Allowing the Φ degree of freedom in the DCM formalism, we calculate the compound-nucleus (CN) and nCN cross sections. The only parameter of the DCM is the neck-length parameter Δ R , which also fits the empirically determined nCN cross section nearly exactly, under the assumption of considering it like a quasifission process where the fragment preformation factor P0=1 . Results: With the Φ degree of freedom included, at the higher two energies the nCN cross section gets enhanced, and hence the pure CN cross section is decreased, since the calculated (total) fusion cross section is fitted to experimental data. The parameter Δ R for the nCN contribution is smaller, and hence the reaction time larger, than for the CN decay process. Also, the contributing angular momentum ℓmax value increases in going from Φc=00 to Φc≠00 for both the CN and nCN processes. The intermediate mass fragments (IMFs), measured up to mass 13 in this reaction, are shown extended up to mass 16, and the fusion-fission (f f ) region is identified as A /2 ±16 , the same as for the Φc=00 case. Conclusions: As a result of enhanced nCN cross section due to Φc≠00 , the CN fusion probability PCN for *105Ag changes its behavior from an increasing to a

  14. Evidence for a pairing anti-halo effect in the odd-even staggering in reaction cross sections of weakly bound nuclei

    SciTech Connect

    Hagino, K.; Sagawa, H.

    2011-07-15

    We investigate the spatial extension of weakly bound Ne and C isotopes by taking into account the pairing correlation with the Hartree-Fock-Bogoliubov (HFB) method and a three-body model, respectively. We show that the odd-even staggering in the reaction cross sections of {sup 30,31,32}Ne and {sup 14,15,16}C are successfully reproduced, and thus the staggering can be attributed to the pairing anti-halo effect. A correlation between a one-neutron separation energy and the anti-halo effect is demonstrated for s and p waves using the HFB wave functions.

  15. A direct underground measurement of the {sup 17}O(p,α){sup 14}N reaction cross-section at energies of astrophysical interest

    SciTech Connect

    Bruno, C. G.; Collaboration, LUNA

    2014-05-09

    The {sup 17}O(p,α){sup 14}N reaction plays a key role in many stellar sites, including classical novae and massive stars. Our knowledge of these scenarios might be improved by a precise measurement of the reaction’s cross-section at astrophysical energies. A direct attempt is currently underway in the Gran Sasso Laboratory, Italy, using the underground LUNA 400kV accelerator. The background reduction afforded by the underground environment is essential to the success of this challenging measurement. A purpose-built experimental setup has been simulated and commissioned. Preliminary results are presented.

  16. Extracting the cross section angular distributions for 15C high-energy resonance excited via the (18O,16O) two-neutron transfer reaction

    NASA Astrophysics Data System (ADS)

    Carbone, D.; Agodi, C.; Cappuzzello, F.; Cavallaro, M.; Foti, A.; Linares, R.

    2016-05-01

    The 13C(18O,16O)15C reaction has been studied at 84 MeV incident energy. The ejectiles have been momentum analized by the MAGNEX spectrometer and 15C excitation energy spectra have been obtained up to about 20 MeV. In the region above the two-neutron separation energy, a bump has been observed at 13.7 MeV. The extracted cross section angular distribution for this structure, obtained by using different models for background, displays a clear oscillating pattern, typical of resonant state of the residual nucleus.

  17. Extension of the energy range of experimental activation cross-sections data of deuteron induced nuclear reactions on indium up to 50MeV.

    PubMed

    Tárkányi, F; Ditrói, F; Takács, S; Hermanne, A; Ignatyuk, A V

    2015-11-01

    The energy range of our earlier measured activation cross-sections data of longer-lived products of deuteron induced nuclear reactions on indium were extended from 40MeV up to 50MeV. The traditional stacked foil irradiation technique and non-destructive gamma spectrometry were used. No experimental data were found in literature for this higher energy range. Experimental cross-sections for the formation of the radionuclides (113,110)Sn, (116m,115m,114m,113m,111,110g,109)In and (115)Cd are reported in the 37-50MeV energy range, for production of (110)Sn and (110g,109)In these are the first measurements ever. The experimental data were compared with the results of cross section calculations of the ALICE and EMPIRE nuclear model codes and of the TALYS 1.6 nuclear model code as listed in the on-line library TENDL-2014. PMID:26226220

  18. Diffractive, inelastic and total cross sections in high energy pp, pA and γ*A reactions with the dipole formalism

    SciTech Connect

    Ster, Andras

    2015-04-10

    The Lund Monte Carlo model DIPSY has recently been extended to ions to study elastic, inelastic and diffractive processes in high energy collisions between electrons, protons and nuclei. In this BFKL-based dipole formalism of parton interactions fluctuations are naturally included and adding them to the pomeron ladder substantially determine the diffractive excitation cross sections of the processes. Starting from √(s{sub NN})=200 GeV and √(s{sub γ*N})=100 GeV we provide results for pp, pA and γ*A total, inelastic and diffractive cross sections that are shown and discussed in case of pp, pO, pCu, pPb and γ*Au reactions. We find good agreement with pp and pPb data. We find that the diffractive cross sections are relatively small compared to the total ones but with increasing collision energies they grow faster than the elastic or the inelastic ones. We make a comparison to calculations obtained by the more conventional method of the Glauber Model MC, too.

  19. Detailed determination of the nuclear fusion radius by a simultaneous optical model calculation of elastic scattering and fusion cross sections in reactions involving weakly bound projectiles

    SciTech Connect

    Camacho, A. Gomez; Aguilera, E. F.; Gomes, P. R. S.; Lubian, J.

    2007-10-15

    Within the optical model for direct reactions, simultaneous calculations of elastic scattering, complete fusion, and total reaction cross sections for energies around the Coulomb barrier are presented for reactions involving the weakly bound projectile {sup 9}Be on {sup 64}Zn. Volume (W{sub F}) and surface (W{sub DR}) Woods-Saxon optical potentials are used such that the former is responsible only for complete fusion reactions while the latter for all direct reactions plus incomplete fusion. Simultaneous fits can be obtained with several sets of potential parameters, but if we impose the condition that the strength of W{sub F} is smaller than the strength of W{sub DR} at the tail region of the potential (this condition is discussed in detail), then values are required for r{sub F} and r{sub DR} of around 1.6 and 1.7-1.9 fm, respectively. These values are much larger than those frequently used in barrier penetration model calculations. Through the energy dependence of the real and imaginary parts of the polarization potentials, we show that the usual threshold anomaly does not show up for this system, but instead there is evidence of the presence of a breakup threshold anomaly.

  20. Microscopic study of the Sn132,124+Zr96 reactions: Dynamic excitation energy, energy-dependent heavy-ion potential, and capture cross section

    NASA Astrophysics Data System (ADS)

    Oberacker, V. E.; Umar, A. S.; Maruhn, J. A.; Reinhard, P.-G.

    2010-09-01

    We study reactions between neutron-rich Sn132 nucleus and Zr96 within a dynamic microscopic theory at energies in the vicinity of the ion-ion potential barrier peak, and we compare the properties to those of the stable system Sn124+Zr96. The calculations are carried out on a three-dimensional lattice using the density-constrained time-dependent Hartree-Fock method. In particular, we calculate the dynamic excitation energy E*(t) during the initial stages of the collision. The barrier heights and widths of the heavy-ion potential increase substantially with Ec.m. energy. The capture cross sections for the two reactions are of similar magnitude, but the interaction barrier for the neutron-rich system is found to be significantly (9 MeV) lower. A comparison with recently measured data is given.

  1. Averaging cross section data so we can fit it

    SciTech Connect

    Brown, D.

    2014-10-23

    The 56Fe cross section we are interested in have a lot of fluctuations. We would like to fit the average of the cross section with cross sections calculated within EMPIRE. EMPIRE is a Hauser-Feshbach theory based nuclear reaction code, requires cross sections to be smoothed using a Lorentzian profile. The plan is to fit EMPIRE to these cross sections in the fast region (say above 500 keV).

  2. Neutron-capture Cross Sections from Indirect Measurements

    SciTech Connect

    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.

  3. Measurement of thermal neutron cross section and resonance integral for the {sup 170}Er(n,{gamma}){sup 171}Er reaction by using a {sup 55}Mn monitor

    SciTech Connect

    Yuecel, Haluk; Budak, M. Gueray; Karadag, Mustafa

    2007-09-15

    The thermal neutron cross section and the resonance integral of the reaction {sup 170}Er(n,{gamma}){sup 171}Er were measured by the Cd-ratio method using a {sup 55}Mn monitor as single comparator. Analytical grade MnO{sub 2} and Er{sub 2}O{sub 3} powder samples with and without a cylindrical 1 mm Cd shield box were irradiated in an isotropic neutron field obtained from three {sup 241}Am-Be neutron sources. The induced activities in the samples were measured with a 120.8% relative efficiency p-type HPGe detector. The correction factors for gamma-ray attenuation (F{sub g}), thermal neutron self-shielding (G{sub th}), and resonance neutron self-shielding (G{sub epi}) effects, and the epithermal neutron spectrum shape factor ({alpha}) were taken into account. The thermal neutron cross section for the (n,{gamma}) reaction in {sup 170}Er has been determined to be 8.00 {+-} 0.56 b, relative to that of the {sup 55}Mn monitor. However, some previously reported experimental results compared to the present result show a large discrepancy ranging from 8.3 to 86%. The present result is, in general, in good agreement with the recently measured values by 9%. According to the definition of Cd cut-off energy at 0.55 eV, the resonance integral obtained is 44.5 {+-} 4.0 b, which is determined relative to the reference integral value of the {sup 55}Mn monitor by using cadmium ratios. The existing experimental data for the resonance integral are distributed between 18 and 43 b. The present resonance integral value agrees only with the measurement of 43 {+-} 5 b by Gillette [Thermal Cross Section and Resonance Integral Studies, ORNL-4155, 15 (1967)] within uncertainty limits.

  4. Extracting the photoproduction cross sections off the neutron, via the γn→π-p reaction, from deuteron data with final-state interaction effects

    NASA Astrophysics Data System (ADS)

    Tarasov, V. E.; Briscoe, W. J.; Gao, H.; Kudryavtsev, A. E.; Strakovsky, I. I.

    2011-09-01

    The incoherent pion photoproduction reaction γd→π-pp is considered theoretically in a wide energy region Eth≤Eγ≤2700 MeV. The model applied contains the impulse approximation as well as the NN and πN final-state-interaction (FSI) amplitudes. The aim of the paper is to study a reliable way for getting the information on elementary γn→π-p reaction cross sections beyond the impulse approximation for γd→π-pp. For the elementary γN→πN, NN→NN, and πN→πN amplitudes, the results of The George Washington University (GW) Data Analysis Center (DAC) are used. There are no additional theoretical constraints. The calculated cross sections dσ/dΩ(γd→π-pp) are compared with existing data. The procedure used to extract information on the differential cross section dσ/dΩ(γn→π-p) on the neutron from the deuteron data using the FSI correction factor R is discussed. The calculations for R versus π-p center-of-mass (CM) angle θ1 of the outgoing pion are performed at different photon-beam energies with kinematic cuts for a “quasifree” process γn→π-p. The results show a sizable FSI effect R≠1 from the S-wave part of pp-FSI at small angles close to θ1˜0: this region narrows as the photon energy increases. At larger angles, the effect is small (|R-1|≪1) and agrees with estimations of FSI in the Glauber approach.

  5. Determination of cross sections for the 238U(n,3n)236U reaction induced by 14-MeV neutrons with accelerator mass spectrometry

    NASA Astrophysics Data System (ADS)

    Wang, Xianggao; Jiang, Shan; He, Ming; Dong, Kejun; Xiao, Caijing; Hu, Yueming; You, Qubo; Chen, Hongtao; Hou, Long; Yu, WeiXiang; Ruan, Xichao

    2013-01-01

    The cross sections of the 238U(n,3n)236U reaction induced by neutrons with energies around 14 MeV were determined using a combination of the activation technique and accelerator mass spectrometry (AMS) at the China Institute of Atomic Energy (CIAE). U3O8 samples were irradiated for 198 h by neutrons produced by the 3H(d,n)4He reaction on a 600-kV neutron generator at CIAE. Neutron flux was continuously determined by the activation of flux monitors, Co foils, closely attached to the sample. To accurately determine the long half-life product 236U, an AMS procedure was established with a sensitivity of about 10-11 for 236U/238U. As a result, the cross sections of 238U(n,3n)236U for the incident neutron energies of (14.18±0.30) and (14.65±0.40) MeV were obtained to be (489.3±48.0) and (556.7±27.8) mb, respectively.

  6. New Measurements of Reaction Cross Sections and Reduced Strong Absorption Radii of Neutron-Rich Exotic Nuclei in the Vicinity of Closed Shells N=20 and N=28

    NASA Astrophysics Data System (ADS)

    Khouaja, A.; Villari, A. C. C.; Benjelloun, M.; Hirata, D.; Savajols; Mittig, W.; Roussel-Chomaz, P.; Orr, N. A.; Pita, S.; Demonchy, C. E.; Giot, L.; Chartier, M.; Gillibert, A.; Baiborodin, D.; Penionzhkevich, Y.; Catford, W. N.; Lépine-Szily, A.; Dlouhy, Z.

    2005-09-01

    Mean energy integrated reaction cross-section measurements for various neutron-rich nuclei covering the region of closed shells N=20 and N=28 were performed, at intermediate energy (30 - 65 A.MeV), via direct method, where the Silicon detectors are used as an active target. Assuming that the energy dependence of the reaction cross-section is well described by the parametrization of S.Kox, the reduced strong absorption radius r02 is extracted for the first time, for 19 new nuclei, i.e. 27F, 27,30Ne, 33Na, 28,34-35Mg, 36-38Al, 38-40Si, 41-42P, 42-44S, 45Cl. Other 60 radii also measured in this experiment are compared to results from literature. The evolution of the reduced strong absorption radius is studied as a function of the neutrons excess. A new quadratic parametrization is therefore proposed for the nuclear radius as a function of the isospin in the region of closed shells N=8 and N=28. According to this parametrization, the skin effect is well reproduced and anomalous behaviours are observed to the nuclei 23N, 29Ne, 33Na, 35Mg, 44S, 45Cl and 45Ar.

  7. Cross sections at hadron colliders

    SciTech Connect

    Paige, F.E.

    1982-01-01

    The predicted cross sections are given for new Z'/sup 0/ bosons, for the Drell-Yan continuum of ..mu../sup +/..mu../sup -/ pairs, for high p/sub T/ hadron jets, for high p/sub T/ single photons, and for the associated production of heavy quarks. These processes have been selected not to cover the most interesting physics, but to provide a representative selection of cross sections for which to compare various energies and luminosities.

  8. Investigation of coulomb and pairing effects using new developed empirical formulas for proton-induced reaction cross sections

    SciTech Connect

    Tel, E. Aydin, E. G.; Aydin, A.; Kaplan, A.; Boeluekdemir, M. H.; Okuducu, S.

    2010-03-15

    We have investigated Coulomb and pairing effects by using new empirical formulas including the new coefficients for (p, {alpha}) at 17.9 MeV, (p, np) at 22.3 MeV, and (p, n{alpha}) at 24.8 and 28.5 MeV energies. A new formula is obtained by adjusting Levkovskii's original asymmetry parameter formula and also Tel et al. formula for proton-induced reactions. The new coefficients by using least-squares fitting method for the reactions are determined. In addition, the findings of the present study are compared with the available experimental data.

  9. A Modified activation method for reaction total cross section and yield measurements at low astrophysically relevant energies

    NASA Astrophysics Data System (ADS)

    Artemov, S. V.; Igamov, S. B.; Karakhodjaev, A. A.; Radyuk, G. A.; Tojiboyev, O. R.; Salikhbaev, U. S.; Ergashev, F. Kh.; Nam, I. V.; Aliev, M. K.; Kholbaev, I.; Rumi, R. F.; Khalikov, R. I.; Eshkobilov, Sh. Kh.; Muminov, T. M.

    2016-07-01

    The activation method is proposed for collection of the sufficient statistics during the investigation of the nuclear astrophysical reactions at low energies with the short-living residual nuclei formation. The main feature is a multiple cyclical irradiation of a target by an ion beam and measurement of the radioactivity decay curve. The method was tested by the yield measurement of the 12C(p,γ)13N reaction with detecting the annihilation γγ- coincidences from 13N(β+ν)13C decay at the two-arm scintillation spectrometer.

  10. Comment on 'Low-energy cross sections in the {sup 12}C({alpha},{gamma}){sup 16}O reaction'

    SciTech Connect

    Descouvemont, P.; Dufour, M.

    2010-02-15

    We show that the E1 and E2 S factors recommended by Katsuma [Phys. Rev. C 78, 034606 (2008)] do not include well-known constraints and that the model is inappropriate for the {sup 12}C({alpha},{gamma}){sup 16}O reaction.

  11. First Direct Measurement of the O17(p,γ)F18 Reaction Cross Section at Gamow Energies for Classical Novae

    NASA Astrophysics Data System (ADS)

    Scott, D. A.; Caciolli, A.; Di Leva, A.; Formicola, A.; Aliotta, M.; Anders, M.; Bemmerer, D.; Broggini, C.; Campeggio, M.; Corvisiero, P.; Elekes, Z.; Fülöp, Zs.; Gervino, G.; Guglielmetti, A.; Gustavino, C.; Gyürky, Gy.; Imbriani, G.; Junker, M.; Laubenstein, M.; Menegazzo, R.; Marta, M.; Napolitani, E.; Prati, P.; Rigato, V.; Roca, V.; Somorjai, E.; Salvo, C.; Straniero, O.; Strieder, F.; Szücs, T.; Terrasi, F.; Trezzi, D.

    2012-11-01

    Classical novae are important contributors to the abundances of key isotopes, such as the radioactive F18, whose observation by satellite missions could provide constraints on nucleosynthesis models in novae. The O17(p,γ)F18 reaction plays a critical role in the synthesis of both oxygen and fluorine isotopes, but its reaction rate is not well determined because of the lack of experimental data at energies relevant to novae explosions. In this study, the reaction cross section has been measured directly for the first time in a wide energy range Ec.m.≃200-370keV appropriate to hydrogen burning in classical novae. In addition, the Ec.m.=183keV resonance strength, ωγ=1.67±0.12μeV, has been measured with the highest precision to date. The uncertainty on the O17(p,γ)F18 reaction rate has been reduced by a factor of 4, thus leading to firmer constraints on accurate models of novae nucleosynthesis.

  12. First direct measurement of the 17O(p,γ)18F reaction cross section at Gamow energies for classical novae.

    PubMed

    Scott, D A; Caciolli, A; Di Leva, A; Formicola, A; Aliotta, M; Anders, M; Bemmerer, D; Broggini, C; Campeggio, M; Corvisiero, P; Elekes, Z; Fülöp, Zs; Gervino, G; Guglielmetti, A; Gustavino, C; Gyürky, Gy; Imbriani, G; Junker, M; Laubenstein, M; Menegazzo, R; Marta, M; Napolitani, E; Prati, P; Rigato, V; Roca, V; Somorjai, E; Salvo, C; Straniero, O; Strieder, F; Szücs, T; Terrasi, F; Trezzi, D

    2012-11-16

    Classical novae are important contributors to the abundances of key isotopes, such as the radioactive (18)F, whose observation by satellite missions could provide constraints on nucleosynthesis models in novae. The (17)O(p,γ)(18)F reaction plays a critical role in the synthesis of both oxygen and fluorine isotopes, but its reaction rate is not well determined because of the lack of experimental data at energies relevant to novae explosions. In this study, the reaction cross section has been measured directly for the first time in a wide energy range E(c.m.)~/= 200-370 keV appropriate to hydrogen burning in classical novae. In addition, the E(c.m.)=183 keV resonance strength, ωγ=1.67±0.12 μeV, has been measured with the highest precision to date. The uncertainty on the (17)O(p,γ)(18)F reaction rate has been reduced by a factor of 4, thus leading to firmer constraints on accurate models of novae nucleosynthesis. PMID:23215474

  13. Evaluation of nuclear reaction cross section data for the production of (87)Y and (88)Y via proton, deuteron and alpha-particle induced transmutations.

    PubMed

    Zaneb, H; Hussain, M; Amjad, N; Qaim, S M

    2016-06-01

    Proton, deuteron and alpha-particle induced reactions on (87,88)Sr, (nat)Zr and (85)Rb targets were evaluated for the production of (87,88)Y. The literature data were compared with nuclear model calculations using the codes ALICE-IPPE, TALYS 1.6 and EMPIRE 3.2. The evaluated cross sections were generated; therefrom thick target yields of (87,88)Y were calculated. Analysis of radio-yttrium impurities and yield showed that the (87)Sr(p, n)(87)Y and (88)Sr(p, n)(88)Y reactions are the best routes for the production of (87)Y and (88)Y respectively. The calculated yield for the (87)Sr(p, n)(87)Y reaction is 104 MBq/μAh in the energy range of 14→2.7MeV. Similarly, the calculated yield for the (88)Sr(p, n)(88)Y reaction is 3.2 MBq/μAh in the energy range of 15→7MeV. PMID:27016709

  14. Cross-sections for populating excited states in 150-153Sm via the (p,d) and (p,t) reactions

    NASA Astrophysics Data System (ADS)

    Humby, P.; Simon, A.; Beausang, C. W.; Gell, K.; Tarlow, T.; Vyas, G.; Ross, T. J.; Hughes, R. O.; Burke, J. T.; Casperson, R. J.; Koglin, J.; Ota, S.; Allmond, J. M.; McCleskey, M.; McCleskey, E.; Saastamoinen, A.; Chyzh, R.; Dag, M.

    2014-09-01

    Light ion transfer reactions were used to populate low/medium spin states in 150-154Sm via the (p,p' γ), (p,d γ) and (p,t γ) reactions. The 25 MeV proton beam, with an average current of 1 nA, was provided by the K-150 Cyclotron at the Cyclotron Institute of Texas A&M University. The outgoing charged particles and coincident gamma-rays were detected using the STARLiTeR arrays. STARs (Silicon Telescope Array for Reaction studies), a highly segmented ΔE-E silicon telescope, provides particle identification as well as the energies, times and angular distributions of the protons, deuterons and tritons in the exit channels. LiTeR (Livermore Texas Richmond array), an array of six BGO shielded HPGe clover detectors, records the energy, time and angular distribution of the coincident gamma rays, providing excellent selectivity of the states of interest. Preliminary results for the cross-sections for direct population of states in 150-153Sm will be presented. Light ion transfer reactions were used to populate low/medium spin states in 150-154Sm via the (p,p' γ), (p,d γ) and (p,t γ) reactions. The 25 MeV proton beam, with an average current of 1 nA, was provided by the K-150 Cyclotron at the Cyclotron Institute of Texas A&M University. The outgoing charged particles and coincident gamma-rays were detected using the STARLiTeR arrays. STARs (Silicon Telescope Array for Reaction studies), a highly segmented ΔE-E silicon telescope, provides particle identification as well as the energies, times and angular distributions of the protons, deuterons and tritons in the exit channels. LiTeR (Livermore Texas Richmond array), an array of six BGO shielded HPGe clover detectors, records the energy, time and angular distribution of the coincident gamma rays, providing excellent selectivity of the states of interest. Preliminary results for the cross-sections for direct population of states in 150-153Sm will be presented. This work was partly supported by the US Department of Energy

  15. 242Amm fission cross section

    NASA Astrophysics Data System (ADS)

    Browne, J. C.; White, R. M.; Howe, R. E.; Landrum, J. H.; Dougan, R. J.; Dupzyk, R. J.

    1984-06-01

    The neutron-induced fission cross section of 242Amm has been measured over the energy region from 10-3 eV to ~20 MeV in a series of experiments utilizing a linac-produced "white" neutron source and a monoenergetic source of 14.1 MeV neutrons. The cross section was measured relative to that of 235U in the thermal (0.001 to ~3 eV) and high energy (1 keV to ~20 MeV) regions and normalized to the ENDF/B-V 235U(n,f) evaluated cross section. In the resonance energy region (0.5 eV to 10 keV) the neutron flux was measured using thin lithium glass scintillators and the relative cross section thus obtained was normalized to the thermal energy measurement. This procedure allowed a consistency check between the thermal and high energy data. The cross section data have a statistical accuracy of ~0.5% at thermal energies and in the 1-MeV energy region, and a systematic uncertainty of ~5%. We confirmed that 242Amm has the largest thermal fission cross section known with a 2200 m/sec value of 6328 b. Results of a Breit-Wigner sum-of-single-levels analysis of 48 fission resonances up to 20 eV are presented and the connection of these resonance properties to the large thermal cross section is discussed. Our measurements are compared with previously reported results.

  16. International Evaluation of Neutron Cross Section Standards

    NASA Astrophysics Data System (ADS)

    Carlson, A. D.; Pronyaev, V. G.; Smith, D. L.; Larson, N. M.; Chen, Zhenpeng; Hale, G. M.; Hambsch, F.-J.; Gai, E. V.; Oh, Soo-Youl; Badikov, S. A.; Kawano, T.; Hofmann, H. M.; Vonach, H.; Tagesen, S.

    2009-12-01

    Neutron cross section standards are the basis for the determination of most neutron cross sections. They are used for both measurements and evaluations of neutron cross sections. Not many cross sections can be obtained absolutely - most cross sections are measured relative to the cross section standards and converted using evaluations of the standards. The previous complete evaluation of the neutron cross section standards was finished in 1987 and disseminated as the NEANDC/INDC and ENDF/B-VI standards. R-matrix model fits for the light elements and non-model least-squares fits for all the cross sections in the evaluation were the basis of the combined fits for all of the data. Some important reactions and constants are not standards, but they assist greatly in the determination of the standard cross sections and reduce their uncertainties - these data were also included in the combined fits. The largest experimental database used in the evaluation was prepared by Poenitz and included about 400 sets of experimental data with covariance matrices of uncertainties that account for all cross-energy, cross-reaction and cross-material correlations. For the evaluation GMA, a least-squares code developed by Poenitz, was used to fit all types of cross sections (absolute and shape), their ratios, spectrum-averaged cross sections and thermal constants in one full analysis. But, the uncertainties derived in this manner, and especially those obtained in the R-matrix model fits, have been judged to be too low and unrealistic. These uncertainties were substantially increased prior to their release in the recommended data files of 1987. Modified percentage uncertainties were reassigned by the United States Cross Section Evaluation Working Group's Standards Subcommittee for a wide range of energies, and no covariance (or correlation) matrices were supplied at that time. The need to re-evaluate the cross section standards is based on the appearance of a significant amount of precise

  17. Calculation of state-to-state differential and integral cross sections for atom-diatom reactions with transition-state wave packets

    SciTech Connect

    Zhao, Bin; Sun, Zhigang E-mail: hguo@unm.edu; Guo, Hua E-mail: hguo@unm.edu

    2014-06-21

    A recently proposed transition-state wave packet method [R. Welsch, F. Huarte-Larrañaga, and U. Manthe, J. Chem. Phys. 136, 064117 (2012)] provides an efficient and intuitive framework to study reactive quantum scattering at the state-to-state level. It propagates a few transition-state wave packets, defined by the eigenfunctions of the low-rank thermal flux operator located near the transition state, into the asymptotic regions of the reactant and product arrangement channels separately using the corresponding Jacobi coordinates. The entire S-matrix can then be assembled from the corresponding flux-flux cross-correlation functions for all arrangement channels. Since the transition-state wave packets can be defined in a relatively small region, its transformation into either the reactant or product Jacobi coordinates is accurate and efficient. Furthermore, the grid/basis for the propagation, including the maximum helicity quantum number K, is much smaller than that required in conventional wave packet treatments of state-to-state reactive scattering. This approach is implemented for atom-diatom reactions using a time-dependent wave packet method and applied to the H + D{sub 2} reaction with all partial waves. Excellent agreement with benchmark integral and differential cross sections is achieved.

  18. New activation cross section data on longer lived radio-nuclei produced in proton induced nuclear reaction on zirconium.

    PubMed

    Tárkányi, F; Ditrói, F; Takács, S; Hermanne, A; Al-Abyad, M; Yamazaki, H; Baba, M; Mohammadi, M A

    2015-03-01

    The excitation functions of (96)Nb, (95m)Nb, (95g)Nb, (92m)Nb, (91m)Nb, (90)Nb, (95)Zr, (89)Zr, (88)Zr, (86)Zr, (88)Y, (87m)Y, (87g)Y, (86)Y were measured up to 70MeV proton energy by using the stacked foil technique and the activation method. The new data were compared with the critically analyzed experimental data in the literature and with the TALYS based model results in TENDL-2013 library. The possible role of the investigated reactions in the production of medically relevant (90)Nb, (95m)Nb, (89)Zr, and (88)Y radionuclides is discussed. PMID:25579457

  19. Cross-Section Measurements for (n,xn) Reactions by In-Beam Gamma-Ray Spectroscopy

    NASA Astrophysics Data System (ADS)

    Pavlik, A.; Baumann, P.; Borcea, C.; Jericha, E.; Jokić, S.; Kerveno, M.; Lukić, S.; Meulders, J. P.; Mihailescu, L. C.; Nolte, R.; Plompen, A. J. M.; Raškinytė, I.; N Tof Collaboration

    2005-05-01

    The nuclear reactions 207Pb(n,2n)206Pb and 232Th(n,5n)228Th were studied by measuring prompt gamma-ray emission spectra from the interaction of neutrons with an enriched 207Pb sample and a natTh sample. For 207Pb the measurements were performed at the white neutron beam of the GELINA neutron source at IRMM Geel in the neutron energy range up to 20 MeV. The Th measurements were done at the quasi-monoenergetic 7Li(p,n)7Be neutron source at the Université Catholique de Louvain for five peak neutron energies in the range 29 MeV to 42 MeV. The measurements were complemented by model calculations using the code system EMPIRE-II.

  20. Evaluation of nuclear reaction cross sections for optimization of production of the emerging diagnostic radionuclide ⁵⁵Co.

    PubMed

    Amjed, N; Hussain, M; Aslam, M N; Tárkányi, F; Qaim, S M

    2016-02-01

    The excitation functions of the (54)Fe(d,n)(55)Co, (56)Fe(p,2n)(55)Co and (58)Ni(p,α)(55)Co reactions were analyzed with relevance to the production of the β(+)-emitter (55)Co (T½=17.53 h), a promising cobalt radionuclide for PET imaging. The nuclear model codes ALICE-IPPE, EMPIRE and TALYS were used to check the consistency of the experimental data. The statistically fitted excitation function was employed to calculate the integral yield of the product. The amounts of the radioactive impurities (56)Co and (57)Co were assessed. A comparison of the three investigated production routes is given. PMID:26686974

  1. Cross-Section Measurements for (n,xn) Reactions by In-Beam Gamma-Ray Spectroscopy

    SciTech Connect

    Pavlik, A.; Baumann, P.; Kerveno, M.; Rudolf, G.; Borcea, C.; Mihailescu, L.C.; Jericha, E.; Raskinyte, I.; Jokic, S.; Lukic, S.; Meulders, J.P.; Nolte, R.; Plompen, A.J.M.

    2005-05-24

    The nuclear reactions 207Pb(n,2n)206Pb and 232Th(n,5n)228Th were studied by measuring prompt gamma-ray emission spectra from the interaction of neutrons with an enriched 207Pb sample and a natTh sample. For 207Pb the measurements were performed at the white neutron beam of the GELINA neutron source at IRMM Geel in the neutron energy range up to 20 MeV. The Th measurements were done at the quasi-monoenergetic 7Li(p,n)7Be neutron source at the Universite Catholique de Louvain for five peak neutron energies in the range 29 MeV to 42 MeV. The measurements were complemented by model calculations using the code system EMPIRE-II.

  2. Measurement of the {sup 241}Am(n,2n) reaction cross section from 7.6 MeV to 14.5 MeV

    SciTech Connect

    Tonchev, A. P.; Crowell, A. S.; Fallin, B.; Howell, C. R.; Hutcheson, A.; Tornow, W.; Angell, C. T.; Boswell, M.; Hammond, S.; Karwowski, H. J.; Kelley, J. H.; Pedroni, R. S.; Becker, J. A.; Dashdorj, D.; Kenneally, J.; Macri, R. A.; Stoyer, M. A.; Wu, C. Y.; Bond, E.; Chadwick, M. B.

    2008-05-15

    The (n,2n) cross section of the radioactive isotope {sup 241}Am (T{sub 1/2}=432.6 y) has been measured in the incident neutron energy range from 7.6 to 14.5 MeV in steps of a few MeV using the activation technique. Monoenergetic neutron beams were produced via the {sup 2}H(d,n){sup 3}He reaction by bombarding a pressurized deuterium gas cell with an energetic deuteron beam at the TUNL 10-MV Van de Graaff accelerator facility. The induced {gamma}-ray activity of {sup 240}Am was measured with high-resolution HPGe detectors. The cross section was determined relative to Al, Ni, and Au neutron activation monitor foils, measured in the same geometry. Good agreement is obtained with previous measurements at around 9 and 14 MeV, whereas for a large discrepancy is observed when our data are compared to those reported by Perdikakis et al. near 11 MeV. Very good agreement is found with the END-B/VII evaluation, whereas the JENDL-3.3 evaluation is in fair agreement with our data.

  3. Systematics of the Extraction of the Elementary γn -->π- p Reaction Cross Sections beyond the Impulse Approximation for γd -->π- pp

    NASA Astrophysics Data System (ADS)

    Berroteran, Oliver; Strakovsky, Igor

    2015-10-01

    The radiative decay width of neutral baryons may be extracted from π- and π0 photo-production off the neutron, involving a bound neutron target, requiring the use of model-dependent nuclear final state interaction (FSI) corrections. The cross section for the processes γn -->π- p will be extracted from recent CLAS (E = 400 - 2500 MeV) and MAX-lab (E = 146 - 166 MeV) measurements for γd -->π- pp accounting for Fermi motion effects in the Impulse Approximation (IA) as well as nucleon-nucleon- and pion-nucleon-FSI effects beyond the IA. To test the GW-ITEP FSI code for γn -->π- p in a reliable way to obtain information on systematics of the extraction of the elementary γn -->π- p reaction cross sections beyond the IA for γd -->π- pp, three key factors were chosen and analyzed: (i) The sensitivity to the number of steps of integration for numerical calculations of the five-fold integrals in the determination of FSI amplitudes; (ii) The sensitivity to the alternative deuteron-wave functions. (iii) The sensitivity to the experimental kinematic cut-off of the detected protons (the experimental information is uncertain). Preliminary estimations show that the contribution of all three factors to the overall systematics is less than 4%. U.S. DOE, Office of Science, Office of Nuclear Physics, Grant DE-FG02-99-ER41110.

  4. Quantum mechanical differential and integral cross sections for the C((1)D) + H2(ν = 0, j = 0) → CH(ν', j') + H reaction.

    PubMed

    Shen, Zhitao; Cao, Jianwei; Bian, Wensheng

    2015-04-28

    Accurate quantum dynamics calculations for the C((1)D) + H2 reaction are performed using a real wave packet approach with full Coriolis coupling. The newly constructed ZMB-a ab initio potential energy surface [Zhang et al., J. Chem. Phys. 140, 234301 (2014)] is used. The integral cross sections (ICSs), differential cross sections (DCSs), and product state distributions are obtained over a wide range of collision energies. In contrast to previous accurate quantum dynamics calculations on the reproducing kernel Hilbert space potential energy surface, the present total ICS is much larger at low collision energies, yielding larger rate coefficients in better agreement with experiment and with slight inverse temperature dependence. Meanwhile, interesting nonstatistical behaviors in the DCSs are revealed. In particular, the DCSs display strong oscillations with the collision energy; forward biased product angular distribution appears when only small J partial wave contributions are included; alternate forward and backward biases emerge with very small increments of collision energy; and the rotational state-resolved DCSs show strong oscillations with the scattering angle. Nevertheless, the total DCSs can be roughly regarded as backward-forward symmetric over the whole energy range and are in reasonably good agreement with the available experimental measurements. PMID:25933766

  5. Description of fusion and evaporation residue formation cross sections in reactions leading to the formation of element Z =122 within the Langevin approach

    NASA Astrophysics Data System (ADS)

    Litnevsky, V. L.; Kosenko, G. I.; Ivanyuk, F. A.

    2016-06-01

    We describe the evolution of the compact system formed by the touching of two colliding ions in reactions 58Fe+248Cm → 306-x122 + xn, 64Ni+244Pu → 308-x122 + xn, and 90Zr+208Pb → 298-x122 + xn. The description is carried out within the dynamical multidimensional stochastic approach, based on Langevin equations for the shape degrees of freedom of colliding ions and the compact system. For the approach stage we take into account the shell structure of colliding ions, their orientation in the space, and the effect of tunneling of ions through the Coulomb barrier. By describing the evolution of the compact system formed after the touching of incident ions, the shell structure of the compact system is also taken into account. Within this approach we have calculated the compound nucleus and evaporation residue formation cross sections. These can be compared with the experimental data. We have also clarified the impact of the tunneling effect in the entrance channel on the fusion and evaporation residue cross sections.

  6. Accurate Cross Sections for Microanalysis

    PubMed Central

    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 few elements. Results of systematic plane wave Born approximation calculations with exchange for K, L, and M shell ionization cross sections over the range of electron energies used in microanalysis are presented. Comparisons are made with experimental measurement for selected K shells and it is shown that the plane wave theory is not appropriate for overvoltages less than 2.5 V. PMID:27446747

  7. Investigation of activation cross-sections of proton induced nuclear reactions on natMo up to 40 MeV: New data and evaluation

    NASA Astrophysics Data System (ADS)

    Tárkányi, F.; Ditrói, F.; Hermanne, A.; Takács, S.; Ignatyuk, A. V.

    2012-06-01

    Cross-sections of proton induced nuclear reactions on natural molybdenum have been studied in the frame of a systematic investigation of charged particle induced nuclear reactions on metals for different applications. The excitation functions of 93mTc, 93gTc(m+), 94mTc, 94gTc, 95mTc, 95gTc, 96gTc(m+), 99mTc, 90Mo(cum), 93mMo, 99Mo(cum), 90Nb(cum), 92mNb, 95mNb, 95gNb, 96Nb and 88Zr(cum), 89Zr(cum) were measured up to 40 MeV proton energy by a using stacked foil technique and activation method. The main goals of this work were to study the production possibility of the medically important 99mTc and its 99Mo parent nucleus, to get experimental data for accelerator technology, for monitoring of proton beam, for thin layer activation technique and for testing nuclear reaction theories. The experimental data were compared with critically analysed published data and with the results of model calculations, obtained by using the ALICE-IPPE, EMPIRE-II and TALYS codes.

  8. Cross-sections of the reaction 232Th(p,3n)230Pa for production of 230U for targeted alpha therapy.

    PubMed

    Morgenstern, Alfred; Apostolidis, Christos; Bruchertseifer, Frank; Capote, Roberto; Gouder, Thomas; Simonelli, Federica; Sin, Mihaela; Abbas, Kamel

    2008-10-01

    (230)U/(226)Th is a promising novel alpha-emitter system for application in targeted alpha therapy of cancer. The therapeutic nuclides can be produced by proton irradiation of natural (232)Th according to the reaction (232)Th(p,3n)(230)Pa, followed by subsequent beta decay of (230)Pa to (230)U. In this study, the experimental excitation function for the (232)Th(p,3n)(230)Pa reaction up to 34 MeV proton energy has been measured using the stacked-foil technique. The proton energies in the various foils were calculated with the SRIM 2003 code and gamma-ray spectrometry was used to measure the activities of the various radioisotopes produced. The measured cross-sections are in good agreement with selected literature values and with model calculations using the EMPIRE II code. The reaction (232)Th(p,3n)(230)Pa allows the production of carrier-free (230)U in clinically relevant levels. PMID:18374585

  9. High-Resolution Neutron Capture and Total Cross-Section Measurements, and the Astrophysical 95Mo(n,gamma) Reaction Rate at s-process Temperatures

    SciTech Connect

    Koehler, Paul Edward; Guber, Klaus H; Harvey, John A; Wiarda, Dorothea

    2008-01-01

    Abundances of Mo isotopes predicted by stellar models of the s process are, except for {sup 95}Mo, in good agreement with data from single grains of mainstream presolar SiC. Because the meteorite data seemed sound and no reasonable modification to stellar theory resulted in good agreement for {sup 95}Mo, it has been suggested that the recommended neutron capture reaction rate for this nuclide is 30% too low. Therefore, we have made a new determination of the {sup 95}Mo(n,{gamma}) reaction rate via high-resolution measurements of the neutron-capture and total cross sections of {sup 95}Mo at the Oak Ridge Electron Linear Accelerator. These data were analyzed with the R-matrix code SAMMY to obtain parameters for resonances up to E{sub n} = 10 keV. Also, a small change to our capture apparatus allowed us to employ a new technique to vastly improve resonance spin and parity assignments. These new resonance parameters, together with our data in the unresolved range, were used to calculate the {sup 95}Mo(n,{gamma}) reaction rate at s-process temperatures. We compare the currently recommended rate to our new results and discuss their astrophysical impact.

  10. Measurement of gamma-ray production cross sections in neutron-induced reactions for Al and Pb

    SciTech Connect

    Pavlik, A.; Vonach, H.; Hitzenberger, H.; Nelson, R.O.; Haight, R.C.; Wender, S.A.; Young, P.G.; Chadwick, M.B.

    1995-02-01

    The prompt gamma-radiation from the interaction of fast neutrons with aluminum and lead was measured using the white neutron beam of the WNR facility at the Los Alamos National Laboratory. The samples (Al and isotopically enriched {sup 207}Pb and {sup 208}Pb) were positioned at about 20 m or 41 m distance from the neutron production target. The spectra of the emitted gamma-rays were measured with a high-resolution HPGe detector. The incident neutron energy was determined by the time-of-flight method and the neutron fluence was measured with a U fission chamber. From the aluminum gamma-ray spectra excitation functions for prominent gamma-transitions in various residual nuclei (in the range from O to Al) were derived for neutron energies from 3 MeV to 400 MeV. For lead (n,xn{gamma}) reactions were studied for neutron energies up to 200 MeV by analyzing prominent gamma-transitions in the residual nuclei {sup 200,202,204,206,207,208}Pb. The experimental results were compared with nuclear model calculations using the code GNASH. A good overall agreement was obtained without special parameter adjustments.

  11. Cross sections of proton-induced reactions on 152Gd, 155Gd and 159Tb with emphasis on the production of selected Tb radionuclides

    NASA Astrophysics Data System (ADS)

    Steyn, G. F.; Vermeulen, C.; Szelecsényi, F.; Kovács, Z.; Hohn, A.; van der Meulen, N. P.; Schibli, R.; van der Walt, T. N.

    2014-01-01

    Cross sections are presented for various Dy, Tb and Gd radionuclides produced in the proton bombardment of 159Tb as well as for the reactions 152Gd(p,4n)149Tb and 155Gd(p,4n)152Tb up to 66 MeV. The experimental excitation functions are compared with theoretical predictions by means of the geometry-dependent hybrid (GDH) model as implemented in the code ALICE/ASH, as well as with values from the TENDL-2012 library and previous literature experimental data, where available. Physical yields have been derived for the production of some of the medically important radioterbiums, namely 149Tb (radionuclide therapy), 152Tb (PET) and 155Tb (SPECT). The indirect production of high-purity 155Tb via the decay of its precursor 155Dy is reported. The possibility of a large-scale production facility based on a commercial 70 MeV cyclotron is also discussed.

  12. Longitudinal and Transverse Cross Sections in the {sup 1}H ({ital e},thinspthinsp {ital e}{sup {prime}}{ital K}{sup +}){Lambda} Reaction

    SciTech Connect

    Niculescu, G.; Gueye, P.; Ahmidouch, A.; Assamagan, K.; Avery, S.; Baker, O.K.; Beard, K.; Cha, J.; Eden, T.; Harvey, M.; Hinton, W.; Keppel, C.; Madey, R.; Niculescu, I.; Savage, G.; Tang, L.; Williams, R.; Mohring, R.M.; Beise, E.; Breuer, H.; Chang, C.C.; Chant, N.; Collins, G.; Duncan, F.; Ewell, L.; Gustafsson, K.K.; Lung, A.; Roos, P.; Abbott, D.; Baker, O.K.; Carlini, R.; Dunne, J.; Ent, R.; Keppel, C.; Mack, D.; Majewski, S.; Mitchell, J.; Tang, L.; Vulcan, W.; Wood, S.; Yan, C.; Ahmidouch, A.; Madey, R.; Amatuni, T.A.; Mkrtchyan, H.; Stepanyan, S.; Tadevosian, V.; Ambrozewicz, P.; Martoff, C.J.; Angelescu, T.; Mihul, A.; Teodorescu, L.; Armstrong, C.S.; Finn, M.; Meekins, D.; Bailey, K.; Cummings, W.; Geesaman, D.F.; Hansen, J.; Potterveld, D.; Reinhold, J.; Zeidman, B.; Beedoe, S.; Danagoulian, S.; Jackson, C.; Mtingwa, S.; Sawafta, R.; Volmer, J.; Cisbani, E.; De Leo, R.; Frullani, S.; Garibaldi, F.; Iodice, M.; Leone, T.; Lolos, G.; Perrino, R.; Urciuoli, G.M.; Dutta, D.; Segel, R.; Eyraud, L.; Furget, C.; Kox, S.; Real, J.

    1998-08-01

    The {sup 1}H( e,thinspe{sup {prime}}K{sup +}){Lambda} reaction was studied as a function of the squared four-momentum transfer, Q{sup 2} , and the virtual photon polarization, {var_epsilon} . For each of four Q{sup 2} settings, 0.52, 0.75, 1.00, and 2.00 (GeV/c){sup 2} , the longitudinal and transverse virtual photon cross sections were extracted in measurements at three virtual photon polarizations. The Q{sup 2} dependence of the {sigma}{sub L}/{sigma}{sub T} ratio differs significantly from current theoretical predictions. This, combined with the precision of the measurement, implies a need for revision of existing calculations. {copyright} {ital 1998} {ital The American Physical Society }

  13. Study of the reactions /sup 2/H(d, p)/sup 3/H and /sup 2/H(d,n)/sup 3/He with a polarized deuteron beam. Extrapolation of the cross sections to the low-energy region

    SciTech Connect

    Ad'yasevich, B.P.; Antonenko, V.G.; Bragin, V.N.

    1981-05-01

    On the basis of analysis of experimental data on the vector analyzing power of the nuclear reactions /sup 2/H(d,p)/sup 3/H and /sup 2/H(d,n)/sup 3/He and data on the total cross sections for these reactions at energies from 13 to 485 keV we have separated the total cross sections into partial cross sections for s and p waves and have calculated the total cross sections for very low energies down to 0.3 keV. For these same reactions we have calculated the intensities of production of energetic products in a heated deuterium plasma. A formula for practical calculations of this intensity is obtained.

  14. Measurements of the 86Kr(n ,γ ) 87Kr and 86Kr(n ,2 n ) Kr85m reaction cross sections below En=15 MeV

    NASA Astrophysics Data System (ADS)

    Bhike, Megha; Rubino, E.; Gooden, M. E.; Krishichayan, Tornow, W.

    2015-07-01

    The 86Kr(n ,γ ) 87Kr neutron-capture cross section was measured at 11 energies between 0.37 and 14.8 MeV. Cross-section data for the 86Kr(n ,2 n ) Kr85m reaction were obtained at 9 energies between 10.9 and 14.8 MeV. The data are important for testing calculations used to predict the s -process cross section in the unmeasured energy range above 1 MeV for the 86Kr(n ,γ ) 87Kr reaction, and to check on the consistency of parameters used in talys calculations for the 86Kr(γ ,n ) Krm+g85 cross section. The two data sets could also be used as a nuclear physics based diagnostic tool for studying properties of the deuterium-tritium plasma created in inertial confinement fusion reactions at the National Ignition Facility at Lawrence Livermore National Laboratory.

  15. Adverse Drug Reactions Causing Admission to Medical Wards: A Cross-Sectional Survey at 4 Hospitals in South Africa.

    PubMed

    Mouton, Johannes P; Njuguna, Christine; Kramer, Nicole; Stewart, Annemie; Mehta, Ushma; Blockman, Marc; Fortuin-De Smidt, Melony; De Waal, Reneé; Parrish, Andy G; Wilson, Douglas P K; Igumbor, Ehimario U; Aynalem, Getahun; Dheda, Mukesh; Maartens, Gary; Cohen, Karen

    2016-05-01

    Limited data exist on the burden of serious adverse drug reactions (ADRs) in sub-Saharan Africa, which has high HIV and tuberculosis prevalence. We determined the proportion of adult admissions attributable to ADRs at 4 hospitals in South Africa. We characterized drugs implicated in, risk factors for, and the preventability of ADR-related admissions.We prospectively followed patients admitted to 4 hospitals' medical wards over sequential 30-day periods in 2013 and identified suspected ADRs with the aid of a trigger tool. A multidisciplinary team performed causality, preventability, and severity assessment using published criteria. We categorized an admission as ADR-related if the ADR was the primary reason for admission.There were 1951 admissions involving 1904 patients: median age was 50 years (interquartile range 34-65), 1057 of 1904 (56%) were female, 559 of 1904 (29%) were HIV-infected, and 183 of 1904 (10%) were on antituberculosis therapy (ATT). There were 164 of 1951 (8.4%) ADR-related admissions. After adjustment for age and ATT, ADR-related admission was independently associated (P ≤ 0.02) with female sex (adjusted odds ratio [aOR] 1.51, 95% confidence interval [95% CI] 1.06-2.14), increasing drug count (aOR 1.14 per additional drug, 95% CI 1.09-1.20), increasing comorbidity score (aOR 1.23 per additional point, 95% CI 1.07-1.41), and use of antiretroviral therapy (ART) if HIV-infected (aOR 1.92 compared with HIV-negative/unknown, 95% CI 1.17-3.14). The most common ADRs were renal impairment, hypoglycemia, liver injury, and hemorrhage. Tenofovir disoproxil fumarate, insulin, rifampicin, and warfarin were most commonly implicated, respectively, in these 4 ADRs. ART, ATT, and/or co-trimoxazole were implicated in 56 of 164 (34%) ADR-related admissions. Seventy-three of 164 (45%) ADRs were assessed as preventable.In our survey, approximately 1 in 12 admissions was because of an ADR. The range of ADRs and implicated drugs reflect South Africa's high HIV

  16. Covariance Evaluation Methodology for Neutron Cross Sections

    SciTech Connect

    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.

  17. Evaluation of cross sections for neutron-induced reactions in sodium. [10/sup -5/ eV to 20 MeV

    SciTech Connect

    Larson, D.C.

    1980-09-01

    An evaluation of the neutron-induced cross sections of /sup 23/Na has been done for the energy range from 10/sup -5/ eV to 20 MeV. All significant cross sections are given, including differential cross sections for production of gamma rays. The recommended values are based on experimental data where available, and use results of a consistent model code analysis of available data to predict cross sections where there are no experimental data. This report describes the evaluation that was submitted to the Cross Section Evaluation Working Group (CSEWG) for consideration as a part of the Evaluated Nuclear Data File, Version V, and subsequently issued as MAT 1311. 126 references, 130 figures, 14 tables.

  18. Neutrino cross-sections: Experiments

    SciTech Connect

    Sánchez, F.

    2015-07-15

    Neutrino-nucleus cross-sections are as of today the main source of systematic errors for oscillation experiments together with neutrino flux uncertainties. Despite recent experimental and theoretical developments, future experiments require even higher precisions in their search of CP violation. We will review the experimental status and explore possible future developments required by next generation of experiments.

  19. Experiments on Antiprotons: Antiproton-Nucleon Cross Sections

    DOE R&D Accomplishments Database

    Chamberlain, Owen; Keller, Donald V.; Mermond, Ronald; Segre, Emilio; Steiner, Herbert M.; Ypsilantis, Tom

    1957-07-22

    In this paper experiments are reported on annihilation and scattering of antiprotons in H{sub 2}O , D{sub 2}O, and O{sub 2}. From the data measured it is possible to obtain an antiproton-proton and an antiproton-deuteron cross section at 457 Mev (lab). Further analysis gives the p-p and p-n cross sections as 104 mb for the p-p reaction cross section and 113 mb for the p-n reaction cross section. The respective annihilation cross sections are 89 and 74 mb. The Glauber correction necessary in order to pass from the p-d to the p-n cross section by subtraction of the p-p cross section is unfortunately large and somewhat uncertain. The data are compared with the p-p and p-n cross sections and with other results on p-p collisions.

  20. Critical Evaluation of Chemical Reaction Rates and Collision Cross Sections of Importance in the Earth's Upper Atmosphere and the Atmospheres of Other Planets, Moons, and Comets

    NASA Astrophysics Data System (ADS)

    Huestis, D. L.

    2005-05-01

    We recommend establishment of a long-term program of critical evaluation by domain experts of the rates and cross sections of atomic and molecular processes that are needed for understanding and modeling the atmospheres in the solar system. We envision products resembling those from the ongoing JPL/NASA Panel for Data Evaluation and the efforts of the international combustion modeling community funded by US DOE and its European counterpart. Both of these endeavors already provide some important inputs for modeling the atmospheres of the Earth, planets, moons, and comets. However, their applications restrict the choice of which processes to evaluate and the temperature and pressure ranges to cover, thus leaving large gaps that need to be filled. Interestingly, an older evaluation program once filled some of these gaps. Funded by the US DoD in the 1960s-1980s, the DNA Reaction Rate Handbook provided a thorough treatment of numerous types of collisions and reactions that are important in the Earth's lower ionosphere, and the program even provided funding for new laboratory measurements. Other examples could be given, with the on-line resources at NIST being among the best, but most provide a narrower scope or less critical evaluation. What is needed is not a just a list of processes and numbers (i.e., a "database"), but rather serious comparison of the available information and specific statements from independent expert laboratory/theory data providers about what should be believed, what uncertainty to assign, and what is most in need of redetermination. The major topic areas would include the following: 1. Chemical reactions of neutral atoms and molecules in their ground electronic states 2. Ion-molecule reactions 3. Chemistry, relaxation, and radiation of electronically excited atoms and molecules 4. Vibrational and rotational relaxation and radiation 5. Photoabsorption, photodissociation, and photoionization 6. Electron-impact excitation, dissociation, ionization

  1. Examination of the surrogate ratio method for the determination of the 93Zr(n ,γ )94Zr cross section with Zr,9290(18O,16O)Zr,9492 reactions

    NASA Astrophysics Data System (ADS)

    Yan, S. Q.; Li, Z. H.; Wang, Y. B.; Nishio, K.; Makii, H.; Su, J.; Li, Y. J.; Nishinaka, I.; Hirose, K.; Han, Y. L.; Orlandi, R.; Shen, Y. P.; Guo, B.; Zeng, S.; Lian, G.; Chen, Y. S.; Bai, X. X.; Qiao, L. H.; Liu, W. P.

    2016-07-01

    The relative γ -decay probability ratios of the neutron resonance states in 94Zr and 92Zr populated via two-neutron transfer reactions, 92Zr(18O,16O)94Zr and 90Zr(18O,16O)92Zr , have been measured to test the validity of the surrogate ratio method (SRM) in determining the (n , γ ) reaction cross section. The cross sections of the 93Zr(n ,γ )94Zr reaction are derived from the experimentally obtained ratios and the cross sections of the 91Zr(n ,γ )92Zr reaction in the equivalent neutron energy range of En=0 -8 MeV . The deduced cross sections of 93Zr(n ,γ )94Zr reaction agree with the directly measured ones in the low-energy region, and with the evaluated ENDF/B-VII.1 data at higher energies of En>3 MeV . The agreement supports the concept of the SRM method to indirectly determine the (n ,γ ) reaction cross sections.

  2. Absolute np and pp cross section determinations aimed at improving the standard for cross section measurements

    SciTech Connect

    Laptev, Alexander B; Haight, Robert C; Tovesson, Fredrik; Arndt, Richard A; Briscoe, William J; Paris, Mark W; Strakovsky, Igor I; Workman, Ron L

    2010-01-01

    Purpose of present research is a keeping improvement of the standard for cross section measurements of neutron-induced reactions. The cross sections for np and pp scattering below 1000 MeV are determined based on partial-wave analyses (PW As) of nucleon-nucleon scattering data. These cross sections are compared with the most recent ENDF/B-V11.0 and JENDL-4.0 data files, and the Nijmegen PWA. Also a comparison of evaluated data with recent experimental data was made to check a quality of evaluation. Excellent agreement was found between the new experimental data and our PWA predictions.

  3. Absolute np and pp Cross Section Determinations Aimed At Improving The Standard For Cross Section Measurements

    SciTech Connect

    Laptev, A. B.; Haight, R. C.; Tovesson, F.; Arndt, R. A.; Briscoe, W. J.; Paris, M. W.; Strakovsky, I. I.; Workman, R. L.

    2011-06-01

    Purpose of present research is a keeping improvement of the standard for cross section measurements of neutron-induced reactions. The cross sections for np and pp scattering below 1 GeV are determined based on partial-wave analyses (PWAs) of nucleon-nucleon scattering data. These cross sections are compared with the most recent ENDF/B-VII.0 and JENDL-4.0 data files, and the Nijmegen PWA. Also a comparison of evaluated data with recent experimental data was made to check a quality of evaluation. Excellent agreement was found between the new experimental data and our PWA predictions.

  4. Tables of nuclear cross sections for galactic cosmic rays: Absorption cross sections

    NASA Technical Reports Server (NTRS)

    Townsend, L. W.; Wilson, J. W.

    1985-01-01

    A simple but comprehensive theory of nuclear reactions is presented. Extensive tables of nucleon, deuteron, and heavy-ion absorption cross sections over a broad range of energies are generated for use in cosmic ray shielding studies. Numerous comparisons of the calculated values with available experimental data show agreement to within 3 percent for energies above 80 MeV/nucleon and within approximately 10 percent for energies as low as 30 MeV/nucleon. These tables represent the culmination of the development of the absorption cross section formalism and supersede the preliminary absorption cross sections published previously in NASA TN D-8107, NASA TP-2138, and NASA TM-84636.

  5. Differential Cross Sections for the H + D2 → HD(v' = 3, j' = 4-10) + D Reaction above the Conical Intersection.

    PubMed

    Gao, Hong; Sneha, Mahima; Bouakline, Foudhil; Althorpe, Stuart C; Zare, Richard N

    2015-12-17

    We report rovibrationally selected differential cross sections (DCSs) of the benchmark reaction H + D2 → HD(v' = 3, j' = 4-10) + D at a collision energy of 3.26 eV, which exceeds the conical intersection of the H3 potential energy surface at 2.74 eV. We use the PHOTOLOC technique in which a fluorine excimer laser at 157.64 nm photodissociates hydrogen bromide (HBr) molecules to generate fast H atoms and the HD product is detected in a state-specific manner by resonance-enhanced multiphoton ionization. Fully converged quantum wave packet calculations were performed for this reaction at this high collision energy without inclusion of the geometric phase (GP) effect, which takes into account coupling to the first excited state of the H3 potential energy surface. Multimodal structures can be observed in most of the DCSs up to j' = 10, which is predicted by theory and also well-reproduced by experiment. The theoretically calculated DCSs are in good overall agreement with the experimental measurements, which indicates that the GP effect is not large enough that its existence can be verified experimentally at this collision energy. PMID:26090780

  6. Cross section measurements of proton capture reactions relevant to the p process: The case of 89Y(p,γ)90Zr and 121,123Sb(p,γ)122,124Te

    NASA Astrophysics Data System (ADS)

    Harissopulos, S.; Spyrou, A.; Lagoyannis, A.; Axiotis, M.; Demetriou, P.; Hammer, J. W.; Kunz, R.; Becker, H.-W.

    2013-02-01

    The cross sections of the 89Y(p,γ)90Zr and the 121,123Sb(p,γ)122,124Te reactions were determined from γ-angular distribution measurements at beam energies from 1.6 to 3.4 MeV. In addition, angle-integrated cross sections were also measured at Ep=2, 3, 4, and 4.8 MeV for the 89Y(p,γ)90Zr reaction using the 4π γ-summing method. Astrophysical S factors and reaction rates were deduced from the measured cross sections. Statistical model calculations were performed using the nuclear-reaction code talys. The results from the comparison between theory and experiment are discussed in detail.

  7. Photo-neutron reaction cross-sections for natMo in the bremsstrahlung end-point energies of 12-16 and 45-70 MeV

    NASA Astrophysics Data System (ADS)

    Naik, H.; Kim, G. N.; Kapote Noy, R.; Schwengner, R.; Kim, K.; Zaman, M.; Shin, S. G.; Gey, Y.; Massarczyk, R.; John, R.; Junghans, A.; Wagner, A.; Cho, M.-H.

    2016-07-01

    The natMo( γ, xn)90, 91, 99Mo reaction cross-sections were experimentally determined for the bremsstrahlung end-point energies of 12, 14, 16, 45, 50, 55, 60 and 70MeV by activation and off-line γ -ray spectrometric technique and using the 20MeV electron linac (ELBE) at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany, and the 100MeV electron linac at the Pohang Accelerator Laboratory (PAL), Pohang, Korea. The natMo( γ, xn)88, 89, 90, 91, 99Mo reaction cross-sections as a function of photon energy were also calculated using the computer code TALYS 1.6. The flux-weighted average cross-sections were obtained from the literature data and the calculated values of TALYS based on mono-energetic photons and are found to be in general agreement with the present results. The flux-weighted average experimental and theoretical cross-sections for the natMo( γ, xn)88, 89, 90, 91, 99Mo reactions increase with the bremsstrahlung end-point energy, which indicates the role of excitation energy. After a certain energy, the individual natMo( γ, xn) reaction cross-sections decrease with the increase of bremsstrahlung energy due to opening of other reactions, which indicates sharing of energy in different reaction channels. The 100Mo( γ, n) reaction cross-section is important for the production of 99Mo , which is a probable alternative to the 98Mo(n, γ) and 235U(n, f ) reactions.

  8. Neutron Capture Cross Sections for Radioactive Nuclei

    NASA Astrophysics Data System (ADS)

    Tonchev, Anton; Bedrossian, Peter; Escher, Jutta; Scielzo, Nicholas

    2015-10-01

    Accurate neutron-capture cross sections for radioactive nuclei near or far away from the line of beta stability are crucial for understanding the nucleosynthesis of heavy elements. 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 observables that can constrain Hauser-Feshbach statistical model calculations of capture cross sections. Specifically, we will consider photon scattering, transfer reactions, and beta-delayed neutron emission. Challenges that exist on the path to obtaining neutron-capture cross sections for reactions on isotopes far from stability will be discussed. This work was performed under the auspices of US DOE by LLNL under contract DE-AC52-07NA27344. Funding was provided via the LDRD-ERD-069 project.

  9. Cross-sections of two-prong exclusive reactions in ¯pp Interactions at22.4 GeV/c: Alma Ata-Dubna-Helsinki-Moscow-Prague Collaboration

    NASA Astrophysics Data System (ADS)

    Batyunya, B. V.; Boguslavsky, I. V.; Bruncko, D.; Gramenitsky, I. M.; Lednický, R.; Medved, K. S.; Vrba, V.; Boos, E. G.; Ermilova, D. I.; Temiraliev, T.; Dementiev, R. K.; Rud, V. I.; Korzhavina, I. A.; Tikhonova, L. A.; Levonian, S. V.; Herynek, I.; Lokajíček, M.; Řídký, J.; Šimák, V.; Valkárová, A.; Kanazirsky, H.; Zlatanov, Z.; Villanen, P.; Walck, E.

    1988-03-01

    The results of the cross-section determination of some two-prong final states with one neutral particle (1 C-fits) in ¯ pp-interactions at 22.4 GeV/ c are presented. These results have been obtained from pictures of the HBC “Ludmila”. The methodical problems of the reaction selection are presented, the fulfilling of CP-invariance channels is demonstrated and the energetic behaviour of their cross-sections is analysed.

  10. Fusion cross sections measurements with MUSIC

    NASA Astrophysics Data System (ADS)

    Carnelli, P. F. F.; Fernández Niello, J. O.; Almaraz-Calderon, S.; Rehm, K. E.; Albers, M.; Digiovine, B.; Esbensen, H.; Henderson, D.; Jiang, C. L.; Nusair, O.; Palchan-Hazan, T.; Pardo, R. C.; Ugalde, C.; Paul, M.; Alcorta, M.; Bertone, P. F.; Lai, J.; Marley, S. T.

    2014-09-01

    The interaction between exotic nuclei plays an important role for understanding the reaction mechanism of the fusion processes as well as for the energy production in stars. With the advent of radioactive beams new frontiers for fusion reaction studies have become accessible. We have performed the first measurements of the total fusion cross sections in the systems 10 , 14 , 15C + 12C using a newly developed active target-detector system (MUSIC). Comparison of the obtained cross sections with theoretical predictions show a good agreement in the energy region accessible with existing radioactive beams. This type of comparison allows us to calibrate the calculations for cases that cannot be studied in the laboratory with the current experimental capabilities. The high efficiency of this active detector system will allow future measurements with even more neutron-rich isotopes. The interaction between exotic nuclei plays an important role for understanding the reaction mechanism of the fusion processes as well as for the energy production in stars. With the advent of radioactive beams new frontiers for fusion reaction studies have become accessible. We have performed the first measurements of the total fusion cross sections in the systems 10 , 14 , 15C + 12C using a newly developed active target-detector system (MUSIC). Comparison of the obtained cross sections with theoretical predictions show a good agreement in the energy region accessible with existing radioactive beams. This type of comparison allows us to calibrate the calculations for cases that cannot be studied in the laboratory with the current experimental capabilities. The high efficiency of this active detector system will allow future measurements with even more neutron-rich isotopes. This work is supported by the U.S. DOE Office of Nuclear Physics under Contract No. DE-AC02-06CH11357 and the Universidad Nacional de San Martin, Argentina, Grant SJ10/39.

  11. Cross sections for U238(n,n'γ) and U238(n,2nγ) reactions at incident neutron energies between 5 and 14 MeV

    NASA Astrophysics Data System (ADS)

    Hutcheson, A.; Angell, C.; Becker, J. A.; Crowell, A. S.; Dashdorj, D.; Fallin, B.; Fotiades, N.; Howell, C. R.; Karwowski, H. J.; Kawano, T.; Kelley, J. H.; Kwan, E.; Macri, R. A.; Nelson, R. O.; Pedroni, R. S.; Tonchev, A. P.; Tornow, W.

    2009-07-01

    Precision measurements of U238(n,n'γ) and U238(n,2nγ) partial cross sections have been performed at Triangle Universities Nuclear Laboratory (TUNL) to improve crucial data needed for testing nuclear reaction models in the actinide mass region. A pulsed and monoenergetic neutron beam was used in combination with high-resolution γ-ray spectroscopy to obtain partial cross sections for incident neutron energies between 5 and 14 MeV. γ-ray yields were measured with high-purity germanium clover and planar detectors. Measured partial cross-section data are compared with previous results using white and monoenergetic neutron beams and calculations from the GNASH and TALYS Hauser-Feshbach statistical-model codes. Present experimental results are in fair to good agreement with most of the existing data for the U238(n,n'γ) reaction. However, significant discrepancies are observed for the U238(n,2nγ) reaction.

  12. Inclusive cross-sections of (p,xp) and (p,x{alpha}) reactions on {sup 56}Fe at E{sub p}=29.9 MeV

    SciTech Connect

    Duisebayev, A.; Ismailov, K.M.; Boztosun, I.

    2005-11-01

    In this paper, we present new experimental data measured at E{sub p}= 29.9 MeV for the inclusive reactions (p,xp) and (p,x{alpha}) on nucleus {sup 56}Fe. We investigate the adequacy of the theoretical models in explaining the measured experimental data, and we determine the contributions of multistep direct and multistep compound processes in the formation of the cross-sections. We show that the traditional frameworks are valid for the description of the new experimental data, and our measurements agree with previous measurements for the (p,xp) and (p,x{alpha}) reactions on the {sup 54}Fe nucleus. The only exception is within the energy region of E{sub p}= 15 and 25 MeV for both reactions, where the cross-section for the {sup 56}Fe nucleus is smaller than the cross-section for the {sup 54}Fe nucleus.

  13. Novel 4{pi} Detection System for the Measurement of the {sup 6}Li(n,{alpha}){sup 3}H Reaction Cross Section

    SciTech Connect

    Giorginis, Georgios; Bencardino, Raffaele

    2011-12-13

    A dedicated one-dimensional Time Projection Chamber (1D-TPC) was designed and produced at IRMM to determine the {sup 6}Li(n,{alpha}){sup 3}H cross section in the 0.4-2.8 MeV energy range, aiming at 5% accuracy. The basic TPC components were a twin gridded ionisation chamber (GIC) with interwired electrodes and fast digitisation of the anode and cathode signals. The energy of both reaction products emitted from a thin {sup 6}LiF sample at the common TPC cathode was measured. A Kr(97%)CO{sub 2}(3%) mixture was used as the detector gas at a pressure up to 3.5 bar. A {sup 238}U sample mounted on the cathode of an ionisation chamber without grid was used as the neutron flux monitor. Special care was taken to reduce the experimental sources of uncertainty. The beam-monitor {sup 238}U sample was characterised at IRMM by low-geometry {alpha}-counting with an accuracy of 0.1%. A {sup 6}Li sample was produced at IRMM by vacuum evaporation of {sup 6}LiF onto transparent aluminium backing. The number of {sup 6}Li atoms will be measured via Thermal Neutron Depth Profiling with an expected accuracy of 2% with respect to an IRMM Standard Reference Material. First test measurements were performed using a monoenergetic neutron beam produced by the T(p,n){sup 3}He reaction at the IRMM 7 MV Van de Graaff accelerator. The experimental method and preliminary results are presented.

  14. Reaction cross-section and reduced strong absorption radius measurements of neutron-rich nuclei in the vicinity of closed shells N=20 and N=28

    NASA Astrophysics Data System (ADS)

    Khouaja, A.; Villari, A. C. C.; Benjelloun, M.; Hirata, D.; Auger, G.; Savajols, H.; Mittig, W.; Roussel-Chomaz, P.; Orr, N. A.; Saint-Laurent, M. G.; Pita, S.; Gillibert, A.; Chartier, M.; Demonchy, C. E.; Giot, L.; Baiborodin, D.; Penionzhkevich, Y.; Catford, W. N.; Lépine-Szily, A.; Dlouhy, Z.

    2006-12-01

    The energy-integrated reaction cross-sections of several neutron-rich nuclei ( 17-22N, 19-24O, 21-27F, 23-30Ne, 26-33Na, 28-35Mg, 31-38Al, 33-40Si, 36-42P, 39-44S, 42-45Cl, 45,46Ar), measured at intermediate energy (30-65 A MeV), via direct method, are presented. Silicon detectors have been used as the active target as well as for particles identification. The reduced strong absorption radii r02 are extracted and compared to the data available from the literature. New measurements for 19 nuclei ( 27F, 27,30Ne, 33Na, 28,34-35Mg, 36-38Al, 38-40Si, 41-42P, 42-44S, 45Cl) are revealed. From the study of the isospin dependence of the reduced strong absorption radius, a new quadratic parameterisation of the nuclear radii in the closed shell regions N=8 and N=28, is proposed. According to this parameterisation, the proton/neutron rich nuclei skin effect is well described and a new anomalous structure: halo-structure or large deformation is suggested for 35Mg and 44S nuclei.

  15. Reaction cross-sections and reduced strong absorption radii of nuclei in the vicinity of closed shells N = 20 and N = 28

    NASA Astrophysics Data System (ADS)

    Khouaja, A.; Villari, A. C. C.; Benjelloun, M.; Auger, G.; Baiborodin, D.; Catford, W.; Chartier, M.; Demonchy, C. E.; Dlouhy, Z.; Gillibert, A.; Giot, L.; Hirata, D.; Lépine-Szily, A.; Mittig, W.; Orr, N.; Penionzhkevich, Y.; Pitae, S.; Roussel-Chomaz, P.; Saint-Laurent, M. G.; Savajols, H.

    2005-09-01

    Energy integrated reaction cross-section measurements of around sixty neutron-rich nuclei covering the region of closed shells N = 20 and N = 28 were performed at intermediate energy (30-65 A . MeV) using direct method. In this experiment, silicon detectors were used as active targets. The reduced strong absorption radii, r02, for 19 new nuclei (27F, 27,30Ne, 33Na, 28, 34-35Mg, 36-38Al, 38-40Si, 41-42P, 42-44S and 45Cl) are deduced for the first time. An additional 60 radii, also measured in this experiment, are compared to results from literature. A new quadratic parametrization is proposed for the nuclear radius as a function of the isospin in the region of closed shells N = 8 and N = 28. According to this parametrization, the skin effect is well reproduced and anomalous behaviour on the radii are observed in 23N, 29Ne, 33Na, 35Mg, 44S, 45Cl and 45Ar nuclei.

  16. Measurement of the cross sections of the reactions e +e - → γγ and e +e - → γγγ at LEP

    NASA Astrophysics Data System (ADS)

    Akwawy, M. Z.; Alexander, G.; Allison, J.; Allport, P. P.; Anderson, K. J.; Armitage, J. C.; Arnison, G. T. J.; Ashton, P.; Azuelos, G.; Baines, J. T. M.; Ball, A. H.; Banks, J.; Barker, G. J.; Barlow, R. J.; Batley, J. R.; Beaudoin, G.; Beck, A.; Becker, J.; Behnke, T.; Bell, K. W.; Bella, G.; Bethke, S.; Biebel, O.; Binder, U.; Bloodworth, I. J.; Bock, P.; Breuker, H.; Brown, R. M.; Brun, R.; Buijs, A.; Burckhart, H. J.; Capiluppi, P.; Carnegie, R. K.; Carter, A. A.; Carter, J. R.; Chang, C. Y.; Charlton, D. G.; Chrin, J. T. M.; Clarke, P. E. L.; Cohen, I.; Collins, W. J.; Conboy, J. E.; Couch, M.; Coupland, M.; Cuffiani, M.; Dado, S.; Dallavalle, G. M.; De Jong, S.; Debu, P.; Deninno, M. M.; Dieckmann, A.; Dittmar, M.; Dixit, M. S.; Duchovni, E.; Duerdoth, I. P.; Dumas, D. J. P.; Elcombe, P. A.; Estabrooks, P. G.; Etzion, E.; Fabbri, F.; Farthouat, P.; Fischer, H. M.; Fong, D. G.; French, M. T.; Fukunaga, C.; Gaidot, A.; Ganel, O.; Gary, J. W.; Gascon, J.; Geddes, N. I.; Gee, C. N. P.; Geich-Gimbel, C.; Gensler, S. W.; Gentit, F. X.; Giacomelli, G.; Gibson, V.; Gibson, W. R.; Gillies, J. D.; Goldberg, J.; Goodrick, M. J.; Gorn, W.; Granite, D.; Gross, E.; Grunhaus, J.; Hagedorn, H.; Hagemann, J.; Hansroul, M.; Hargrove, C. K.; Harrus, I.; Hart, J.; Hattersley, P. M.; Hauschild, M.; Hawkes, C. M.; Heflin, E.; Hemingway, R. J.; Heuer, R. D.; Hill, J. C.; Hillier, S. J.; Hinshaw, D. A.; Ho, C.; Hobbs, J. D.; Hobson, P. R.; Hochman, D.; Holl, B.; Homer, R. J.; Hou, S. R.; Howarth, C. P.; Hughes-Jones, R. E.; Humbert, R.; Igo-Kemenes, P.; Ihssen, H.; Imrie, D. C.; Janissen, L.; Jawahery, A.; Jeffreys, P. W.; Jeremie, H.; Jimack, M.; Jobes, M.; Jones, R. W. L.; Jovanovic, P.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Kellogg, R. G.; Kennedy, B. W.; Kleinwort, C.; Klem, D. E.; Knop, G.; Kobayashi, T.; Kokott, T. P.; Köpke, L.; Kowalewski, R.; Kreutzmann, H.; Kroll, J.; Kuwano, M.; Kyberd, P.; Lafferty, G. D.; Lamarche, F.; Larson, W. J.; Layter, J. G.; Le Du, P.; Leblanc, P.; Lee, A. M.; Lehto, M. H.; Lellouch, D.; Lennert, P.; Leroy, C.; Lessard, L.; Levegrün, S.; Levinson, L.; Lloyd, S. L.; Loebinger, F. K.; Lorah, J. M.; Lorazo, B.; Losty, M. J.; Ludwig, J.; Ma, J.; Macbeth, A. A.; Mannelli, M.; Marcellini, S.; Maringer, G.; Martin, A. J.; Martin, J. P.; Mashimo, T.; Mättig, P.; Maur, U.; McMahon, T. J.; McNutt, J. R.; Meijers, F.; Menszner, D.; Merritt, F. S.; Mes, H.; Michelini, A.; Middleton, R. P.; Mikenberg, G.; Mildenberger, J.; Miller, D. J.; Milstene, C.; Minowa, M.; Mohr, W.; Moisan, C.; Montanari, A.; Mori, T.; Moss, M. W.; Murphy, P. G.; Murray, W. J.; Nellen, B.; Nguyen, H. H.; Nozaki, M.; O'Dowd, A. J. P.; O'Neale, S. W.; O'Neill, B. P.; Oakham, F. G.; Odorici, F.; Ogg, M.; Oh, H.; Oreglia, M. J.; Orito, S.; Pansart, J. P.; Patrick, G. N.; Pawley, S. J.; Pfister, P.; Pilcher, J. E.; Pinfold, J. L.; Plane, D. E.; Poli, B.; Pouladdej, A.; Prebys, E.; Pritchard, T. W.; Przysiezniak, H.; Quast, G.; Redmond, M. W.; Rees, D. L.; Regimbald, M.; Riles, K.; Roach, C. M.; Robins, S. A.; Rollnik, A.; Roney, J. M.; Rossberg, S.; Rossi, A. M.; Routenburg, P.; Runge, K.; Runolfsson, O.; Sanghera, S.; Sansum, R. A.; Sasaki, M.; Saunders, B. J.; Schaile, A. D.; Schaile, O.; Schappert, W.; Scharff-Hansen, P.; Schreiber, S.; Schwarz, J.; Shapira, A.; Shen, B. C.; Sherwood, P.; Simon, A.; Singh, P.; Siroli, G. P.; Skuja, A.; Smith, A. M.; Smith, T. J.; Snow, G. A.; Springer, R. W.; Sproston, M.; Stephens, K.; Stier, H. E.; Stroehmer, R.; Strom, D.; Takeda, H.; Takeshita, T.; Taras, P.; Thackray, N. J.; Tsukamoto, T.; Turner, M. F.; Tysarczyk-Niemeyer, G.; Van den plas, D.; Van Kooten, R.; VanDalen, G. J.; Vasseur, G.; Virtue, C. J.; von der Schmitt, H.; von Krogh, J.; Wagner, A.; Wahl, C.; Walker, J. P.; Ward, C. P.; Ward, D. R.; Watkins, P. M.; Watson, A. T.; Watson, N. K.; Weber, M.; Weisz, S.; Wells, P. S.; Wermes, N.; Weymann, M.; Wilson, G. W.; Wilson, J. A.; Wingerter, I.; Winterer, V.-H.; Wood, N. C.; Wotton, S.; Wyatt, T. R.; Yaari, R.; Yang, Y.; Yekutieli, G.; Yoshida, T.; Zeuner, W.; Zorn, G. T.; OPAL Collaboration

    1991-03-01

    The cross section of the pure QED process e +e -→ γγ has been measured using data accumulated during the 1989 and 1990 scans of the Z 0 resonance at LEP. Both the energy dependence and the angular distribution are in good agreement with the QED prediction. Upper limits on the branching ratios of Z 0→ γγ, Z 0→ π0γ and Z 0→ ηγ have been set at 1.4×10 -4, 1.4×10 -4 and 2.0×10 -4 respectively. Lower limits on the cutoff parameters of the modified electron propagator have been found to be Λ+ > 117 GeV and Λ- > 110 GeV. The reaction e +e - → γγγ has also been studied and was found to be consistent with the QED prediction. An upper limit on the branching ratio of Z 0→ γγγ has been set at 6.6 × 10 -5. All the limits are given at 95% confidence level.

  17. Measurements of the ^89Y(n,n')^89Y^m reaction cross section using the ASP D-T fusion source

    NASA Astrophysics Data System (ADS)

    Simons, Andrew; Gardner, Matthew; Williams, Ben; Rubery, Michael

    2012-10-01

    A programme of measurements of the ^89Y(n,n')^89Y^m reaction cross section has commenced at AWE using the ASP accelerator to impinge deuterons onto tritiated titanium layers mounted on copper discs producing fluxes of approximately 10^11 neutrons per second. The neutrons are generated for up to half an hour and are used to excite Yttrium into its first isomeric state at 909.1 keV which then decays with a half life of 15.7 seconds. Two other high purity foils (of ^27Al and ^63,65Cu) are used as a reference to establish consistency between the isotopes energetic and temporal decay signatures. These foils mainly serve to check the reported total neutron fluence, produced by the accelerator, incident on the targets. The activation foils are extracted from the irradiation position by a pneumatic transfer system in ˜ 7 seconds and are transferred to the counting station in 5 to 30 seconds. Data are taken with a BEGe detector and recorded with both a Canberra Genie analogue system and a Xia Pixie-4 digital system. The results from the first campaigns are presented with a discussion of improvements and future plans.

  18. Activation cross sections of α-particle induced nuclear reactions on hafnium and deuteron induced nuclear reaction on tantalum: production of ¹⁷⁸W/(178m)Ta generator.

    PubMed

    Tárkányi, F; Takács, S; Ditrói, F; Hermanne, A; Ignatyuk, A V; Uddin, M S

    2014-09-01

    In the frame of a systematic study of charged particle production routes of medically relevant radionuclei, the excitation function for indirect production of (178m)Ta through (nat)Hf(α,xn)(178)W-(178m)Ta nuclear reaction was measured for the first time up to 40 MeV. In parallel, the side reactions (nat)Hf(α,x)(179,177,176,175)W, (183,182,178g,177,176,175)Ta, (179m,177m,175)Hf were also assessed. Stacked foil irradiation technique and γ-ray spectrometry were used. New experimental cross section data for the (nat)Ta(d,xn)(178)W reaction are also reported up to 40 MeV. The measured excitation functions are compared with the results of the ALICE-IPPE, and EMPIRE nuclear reaction model codes and with the TALYS 1.4 based data in the TENDL-2013 library. The thick target yields were deduced and compared with yields of other charged particle ((p,4n), (d,5n) and ((3)He,x)) production routes for (178)W. PMID:24926946

  19. Measurement of the 58Ni(n,t)56Co, 59Co(n,p)59Fe, and 63Cu(n,{alpha})60Co Reaction Cross Sections from 14 to 20 MeV

    SciTech Connect

    Semkova, V.; Plompen, A.J.M.; Smith, D.L.

    2005-05-24

    Neutron activation cross sections for the 63Cu(n,{alpha})60Co, 59Co(n,p)59Fe, and 58Ni(n,t)56Co reactions were measured in the energy range from 13 to 21 MeV. The irradiations were carried out at the 7-MV Van de Graaff accelerator at IRMM, Geel. Quasi-monoenergetic neutrons were produced via the 3H(d,n)4He reaction at 1-, 2-, 3-, and 4-MeV incident deuteron energy. All reaction cross sections measured in the present work are referenced to the 27Al(n,{alpha})24Na standard reaction cross section. Neutron flux spectra were determined by an activation spectral index method in combination with TOF spectrum measurements. Standard {gamma}-ray spectrometry was employed for the measurement of radioactivity. The measured results are compared with work by other authors, TALYS-0.57 and EMPIRE-II model calculations, and current evaluated data files. The new results contribute substantially to the experimental database of the measured reactions. Recommendations are provided for the best evaluations for the 59Co(n,p)59Fe, and 63Cu(n,{alpha})60Co reactions. For the 58Ni(n,t)56Co reaction no current evaluation is in good agreement with all available data. For this reaction further measurements would help to guide new modeling efforts.

  20. Recommended Dosimetry Cross Section Compendium.

    Energy Science and Technology Software Center (ESTSC)

    1994-07-11

    Version 00 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 sections in a 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-547) and MCNP (CCC-200), in order to compare calculated and measured activities formore » benchmark reactor experiments.« less

  1. Production cross-sections of long-lived radionuclides in deuteron-induced reactions on natural zinc up to 23 MeV

    NASA Astrophysics Data System (ADS)

    Khandaker, Mayeen Uddin; Haba, Hiromitsu; Murakami, Masashi; Otuka, Naohiko

    2015-03-01

    Production cross-sections of long-lived radionuclides 66,67Ga, 64,67Cu, 65,69mZn, and 58m+gCo via a deuteron irradiation on a natural zinc target were measured up to 23 MeV using a stacked-foil activation technique combined with HPGe γ-ray spectrometry. The present results showed partial agreements with the earlier experimental cross-sections and also with the theoretical data extracted from the TENDL-2013 library. Physical thick target yields of the investigated radionuclides were deduced using the measured cross-sections, and they found agreements with the directly measured ones in the literatures except for those reported by Dmitriev et al. for 65Zn. Optimal production pathways of the medically important 67Ga radionuclide using a low energy cyclotron are discussed.

  2. (Fast neutron cross section measurements)

    SciTech Connect

    Not Available

    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.

  3. Extended optical model analyses of elastic scattering, direct reaction, and fusion cross sections for the {sup 9}Be+{sup 208}Pb system at near-Coulomb-barrier energies

    SciTech Connect

    So, W.Y.; Hong, S.W.; Kim, B.T.; Udagawa, T.

    2005-12-15

    Based on the extended optical model approach in which the polarization potential is decomposed into direct reaction (DR) and fusion parts, simultaneous {chi}{sup 2} analyses are performed for elastic scattering, DR, and fusion cross section data for the {sup 9}Be+{sup 208}Pb system at near-Coulomb-barrier energies. Similar {chi}{sup 2} analyses are also performed by taking into account only the elastic scattering and fusion data as was previously done by the present authors, and the results are compared with those of the full analysis including the DR cross section data as well. We find that the analyses using only elastic scattering and fusion data can produce very consistent and reliable predictions of cross sections, particularly when the DR cross section data are incomplete. Discussions are also given on the results obtained from similar analyses made earlier for the {sup 9}Be+{sup 209}Bi system.

  4. TREND code for reconstruction of neutron reaction cross sections and calculation of the Doppler broadening in the region of resolved resonances

    SciTech Connect

    Chichulin, N. L. Kulakov, A. S.

    2010-12-15

    The TREND code is developed for reconstruction of neutron cross sections in the region of resolved resonances from the data of the international evaluated nuclear data libraries using the Reich-Moore, Adler-Adler, and Breit-Wigner formalisms and for calculation of the Doppler broadening of the resulting cross sections within the classical approximation. The TREND code is incorporated into the MCU code package for Monte Carlo reactor calculations. The TREND and MCU codes have been used to evaluate the data of the ROSFOND data bank on uranium and plutonium isotopes in comparison with the data of the ICSBEP data bank.

  5. Universal Parameterization of Absorption Cross Sections

    NASA Technical Reports Server (NTRS)

    Tripathi, R. K.; Cucinotta, Francis A.; Wilson, John W.

    1997-01-01

    This paper presents a simple universal parameterization of total reaction cross sections for any system of colliding nuclei that is valid for the entire energy range from a few AMeV to a few AGeV. The universal picture presented here treats proton-nucleus collision as a special case of nucleus-nucleus collision, where the projectile has charge and mass number of one. The parameters are associated with the physics of the collision system. In general terms, Coulomb interaction modifies cross sections at lower energies, and the effects of Pauli blocking are important at higher energies. The agreement between the calculated and experimental data is better than all earlier published results.

  6. Cross sections for (n, 2n), (n, p) and (n, ) reactions on osmium isotopes in the neutron energy range of 13.5-14.8 MeV.

    PubMed

    Zhao, Liangyong; Yuan, Jilong; Tuo, Fei; Zhang, Yanbin; Kong, Xiangzhong; Liu, Rong; Jiang, Li

    2008-10-01

    Cross sections for (n, 2n), (n, p) and (n, alpha) reactions on the osmium isotopes were measured in the neutron energies 13.5-14.8 MeV by the activation technique with the monitor reaction (93)Nb(n, 2n)(92 m)Nb. Our measurements were carried out by gamma-detection using a coaxial high-purity germanium (HPGe) detector. Natural high-purity osmium powder (99.9%) was fabricated as the samples. The neutron energies were determined by the cross-section ratios for (93)Nb(n, 2n)(92 m)Nb and (90)Zr(n, 2n)(89 m+g)Zr reactions. The fast neutrons were produced by the T(d, n)(4)He reaction. The results obtained were compared with previous data. PMID:18468910

  7. Electron-Impact Ionization Cross Section Database

    National Institute of Standards and Technology Data Gateway

    SRD 107 Electron-Impact Ionization Cross Section Database (Web, free access)   This is a database primarily of total ionization cross sections of molecules by electron impact. The database also includes cross sections for a small number of atoms and energy distributions of ejected electrons for H, He, and H2. The cross sections were calculated using the Binary-Encounter-Bethe (BEB) model, which combines the Mott cross section with the high-incident energy behavior of the Bethe cross section. Selected experimental data are included.

  8. Extension of the energy range of the experimental activation cross-sections data of longer-lived products of proton induced nuclear reactions on dysprosium up to 65MeV.

    PubMed

    Tárkányi, F; Ditrói, F; Takács, S; Hermanne, A; Ignatyuk, A V

    2015-04-01

    Activation cross-sections data of longer-lived products of proton induced nuclear reactions on dysprosium were extended up to 65MeV by using stacked foil irradiation and gamma spectrometry experimental methods. Experimental cross-sections data for the formation of the radionuclides (159)Dy, (157)Dy, (155)Dy, (161)Tb, (160)Tb, (156)Tb, (155)Tb, (154m2)Tb, (154m1)Tb, (154g)Tb, (153)Tb, (152)Tb and (151)Tb are reported in the 36-65MeV energy range, and compared with an old dataset from 1964. The experimental data were also compared with the results of cross section calculations of the ALICE and EMPIRE nuclear model codes and of the TALYS nuclear reaction model code as listed in the latest on-line libraries TENDL 2013. PMID:25644082

  9. Data analysis techniques, differential cross sections, and spin density matrix elements for the reaction γp → Φp

    SciTech Connect

    Dey, B.; Meyer, C. A.; Bellis, M.; Williams, M.; Adhikari, K. P.; Adikaram, D.; Aghasyan, M.; Amaryan, M. J.; Anderson, M. D.; Anefalos Pereira, S.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Bono, J.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Doughty, D.; Dugger, M.; Dupre, R.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Fedotov, G.; Fegan, S.; Fleming, J. A.; Garçon, M.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Glazier, D. I.; Goetz, J. T.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Hafidi, K.; Hanretty, C.; Harrison, N.; Hattawy, M.; Hicks, K.; Ho, D.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Jenkins, D.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Koirala, S.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Lenisa, P.; Livingston, K.; Lu, H.; MacGregor, I. J.D.; Markov, N.; Mayer, M.; McCracken, M. E.; McKinnon, B.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Moriya, K.; Moutarde, H.; Munevar, E.; Munoz Camacho, C.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Pappalardo, L. L.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Peng, P.; Phillips, J. J.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Puckett, A. J. R.; Rimal, D.; Ripani, M.; Ritchie, B. G.; Rizzo, A.; Rossi, P.; Roy, P.; Sabatié, F.; Saini, M. S.; Schott, D.; Schumacher, R. A.; Seder, E.; Senderovich, I.; Sharabian, Y. G.; Simonyan, A.; Smith, E. S.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Sytnik, V.; Taiuti, M.; Tang, W.; Tkachenko, S.; Ungaro, M.; Vernarsky, B.; Vlassov, A. V.; Voskanyan, H.; Voutier, E.; Watts, D. P.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; Zonta, I.

    2014-05-27

    High-statistics measurements of differential cross sections and spin density matrix elements for the reaction γ p → Φp have been made using the CLAS detector at Jefferson Lab. We cover center-of-mass energies (√s) from 1.97 to 2.84 GeV, with an extensive coverage in the Φ production angle. The high statistics of the data sample made it necessary to carefully account for the interplay between the Φ natural lineshape and effects of the detector resolution, that are found to be comparable in magnitude. We study both the charged- (Φ → K⁺K⁻) and neutral- (Φ → K0SK0L) KK̄ decay modes of the Φ. Further, for the charged mode, we differentiate between the cases where the final K⁻ track is directly detected or its momentum reconstructed as the total missing momentum in the event. The two charged-mode topologies and the neutral-mode have different resolutions and are calibrated against each other. Extensive usage is made of kinematic fitting to improve the reconstructed Φ mass resolution. Our final results are reported in 10- and mostly 30-MeV-wide √s bins for the charged- and the neutral-mode, respectively. Possible effects from K⁺Λ* channels with pKK̄ final-states are discussed. These present results constitute the most precise and extensive Φ photoproduction measurements to date and in conjunction with the ω photoproduction results recently published by CLAS, will greatly improve our understanding of low energy vector meson photoproduction.

  10. Data analysis techniques, differential cross sections, and spin density matrix elements for the reaction γp → Φp

    DOE PAGESBeta

    Dey, B.; Meyer, C. A.; Bellis, M.; Williams, M.; Adhikari, K. P.; Adikaram, D.; Aghasyan, M.; Amaryan, M. J.; Anderson, M. D.; Anefalos Pereira, S.; et al

    2014-05-27

    High-statistics measurements of differential cross sections and spin density matrix elements for the reaction γ p → Φp have been made using the CLAS detector at Jefferson Lab. We cover center-of-mass energies (√s) from 1.97 to 2.84 GeV, with an extensive coverage in the Φ production angle. The high statistics of the data sample made it necessary to carefully account for the interplay between the Φ natural lineshape and effects of the detector resolution, that are found to be comparable in magnitude. We study both the charged- (Φ → K⁺K⁻) and neutral- (Φ → K0SK0L) KK̄ decay modes of themore » Φ. Further, for the charged mode, we differentiate between the cases where the final K⁻ track is directly detected or its momentum reconstructed as the total missing momentum in the event. The two charged-mode topologies and the neutral-mode have different resolutions and are calibrated against each other. Extensive usage is made of kinematic fitting to improve the reconstructed Φ mass resolution. Our final results are reported in 10- and mostly 30-MeV-wide √s bins for the charged- and the neutral-mode, respectively. Possible effects from K⁺Λ* channels with pKK̄ final-states are discussed. These present results constitute the most precise and extensive Φ photoproduction measurements to date and in conjunction with the ω photoproduction results recently published by CLAS, will greatly improve our understanding of low energy vector meson photoproduction.« less

  11. Calculation of the cross section for the d(e,e') reaction near the threshold with inclusion of meson exchange currents

    SciTech Connect

    Korchin, A.Y.; Shebeko, A.V.

    1984-01-01

    The dependence of the cross section near the deuteron electrodisintegration threshold on the choice of the model for the NN interaction and for the form factors entering into the meson exchange current operator is studied. The results of the calculations are compared with new experimental data in a broad momentum-transfer range.

  12. Cross-section measurements of the 86Kr(γ,n) reaction to probe the s-process branching at 85Kr.

    PubMed

    Raut, R; Tonchev, A P; Rusev, G; Tornow, W; Iliadis, C; Lugaro, M; Buntain, J; Goriely, S; Kelley, J H; Schwengner, R; Banu, A; Tsoneva, N

    2013-09-13

    We have carried out photodisintegration cross-section measurements on 86Kr using monoenergetic photon beams ranging from the neutron separation energy, S(n) = 9.86  MeV, to 13 MeV. We combine our experimental 86Kr(γ,n)85Kr cross section with results from our recent 86Kr(γ,γ') measurement below the neutron separation energy to obtain the complete nuclear dipole response of 86Kr. The new experimental information is used to predict the neutron capture cross section of 85Kr, an important branching point nucleus on the abundance flow path during s-process nucleosynthesis. Our new and more precise 85Kr(n,γ)86Kr cross section allows us to produce more precise predictions of the 86Kr abundance from s-process models. In particular, we find that the models of the s process in asymptotic giant branch stars of mass <1.5M⊙, where the 13C neutron source burns convectively rather than radiatively, represent a possible solution for the highest 86Kr:82Kr ratios observed in meteoritic stardust SiC grains. PMID:24074078

  13. Photoproduction total cross section and shower development

    NASA Astrophysics Data System (ADS)

    Cornet, F.; García Canal, C. A.; Grau, A.; Pancheri, G.; Sciutto, S. J.

    2015-12-01

    The total photoproduction cross section at ultrahigh energies is obtained using a model based on QCD minijets and soft-gluon resummation and the ansatz that infrared gluons limit the rise of total cross sections. This cross section is introduced into the Monte Carlo system AIRES to simulate extended air showers initiated by cosmic ray photons. The impact of the new photoproduction cross section on common shower observables, especially those related to muon production, is compared with previous results.

  14. Measurement of flux-weighted average cross-sections and isomeric yield ratios for 103Rh(γ,xn) reactions in the bremsstrahlung end-point energies of 55 and 60 MeV

    NASA Astrophysics Data System (ADS)

    Shakilur Rahman, Md.; Kim, Kwangsoo; Kim, Guinyun; Naik, Haladhara; Nadeem, Muhammad; Thi Hien, Nguyen; Shahid, Muhammad; Yang, Sung-Chul; Cho, Young-Sik; Lee, Young-Ouk; Shin, Sung-Gyun; Cho, Moo-Hyun; Woo Lee, Man; Kang, Yeong-Rok; Yang, Gwang-Mo; Ro, Tae-Ik

    2016-07-01

    We measured the flux-weighted average cross-sections and the isomeric yield ratios of 99m, g, 100m, g, 101m, g, 102m, gRh in the 103Rh( γ, xn) reactions with the bremsstrahlung end-point energies of 55 and 60MeV by the activation and the off-line γ-ray spectrometric technique, using the 100MeV electron linac at the Pohang Accelerator Laboratory (PAL), Korea. The flux-weighted average cross-sections were calculated by using the computer code TALYS 1.6 based on mono-energetic photons, and compared with the present experimental data. The flux-weighted average cross-sections of 103Rh( γ, xn) reactions in intermediate bremsstrahlung energies are the first time measurement and are found to increase from their threshold value to a particular value, where the other reaction channels open up. Thereafter, it decreases with bremsstrahlung energy due to its partition in different reaction channels. The isomeric yield ratios (IR) of 99m, g, 100m, g, 101m, g, 102m, gRh in the 103Rh( γ, xn) reactions from the present work were compared with the literature data in the 103Rh(d, x), 102-99Ru(p, x) , 103Rh( α, αn) , 103Rh( α, 2p3n) , 102Ru(3He, x), and 103Rh( γ, xn) reactions. It was found that the IR values of 102, 101, 100, 99Rh in all these reactions increase with the projectile energy, which indicates the role of excitation energy. At the same excitation energy, the IR values of 102, 101, 100, 99Rh are higher in the charged particle-induced reactions than in the photon-induced reaction, which indicates the role of input angular momentum.

  15. Cross Sections: No. 1 Hold section at Fr 24 Looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Cross Sections: No. 1 Hold section at Fr 24 Looking Fwd, No 1 Hold Section at Fr 28 Looking Aft, No 2 Hold Section at Fr 48 Looking Aft, No 3 Hold Section at Fr 70 Looking Aft, No 4 Hold Section at Fr 90 Looking Aft - General John Pope, Suisun Bay Reserve Fleet, Benicia, Solano County, CA

  16. Measurement of the cross section for the reaction {sup 20}Ne(n,{alpha}){sup 17}O in the neutron-energy between 4 and 7 MeV

    SciTech Connect

    Khryachkov, V. A.; Bondarenko, I. P.; Kuzminov, B. D.; Semenova, N. N.; Sergachev, A. I.

    2012-04-15

    The cross section for the reaction {sup 20}Ne(n, {alpha}){sup 17}O was measured in the neutron-energy range 4-7 MeV. An ionization chamber equipped with a Frisch grid combined with a pulse-shape digitizer was used as a detector. Gaseous neon that served as a target on which the reaction being studied proceeded was added to the gas filling the ionization chamber. The partial cross sections for the {alpha}{sub 0}, {alpha}{sub 1}, {alpha}{sub 2}, and {alpha}{sub 3} channels of the reaction {sup 20}Ne(n, {alpha}){sup 17}O were obtained for the first time.

  17. New data on cross-sections of deuteron induced nuclear reactions on gold up to 50 MeV and comparison of production routes of medically relevant Au and Hg radioisotopes

    NASA Astrophysics Data System (ADS)

    Tárkányi, F.; Hermanne, A.; Ditrói, F.; Takács, S.; Adam Rebeles, R.; Ignatyuk, A. V.

    2015-11-01

    Investigations of cross-sections of deuteron induced nuclear reactions on gold were extended up to 50 MeV by using the standard stacked foil irradiation technique and high resolution gamma-ray spectrometry. New cross-sections are reported for the 197Au(d,xn)197m,197g,195m,195g,193m,193gHg and 197Au(d,x)198m,198g,196m,196g,195,194Au nuclear reactions. The application for production of the medically relevant isotopes 198Au and 195m,195g,197m,197gHg is discussed, including the comparison with other charged particle induced production routes. The possible use of the 197Au(d,x)197m,197g,195m,193mHg and 196m,196gAu reactions for monitoring deuteron beam parameters is also investigated.

  18. Electron Photon Interaction Cross Sections

    Energy Science and Technology Software Center (ESTSC)

    2014-11-01

    Version 00 The Electron Photon Interaction Cross Sections, EPICS, provides the atomic data needed to perform coupled Electron-Photon transport calculations, to produce accurate macroscopic results, such as energy deposit and dose. Atomic data is provided for elements, Z = 1 to 100, over the energy range 10 eV to 100 GeV; note that nuclear data, such as photo-nuclear, and data for compounds, are not included. All data is in a simple computer independent text formatmore » that is standard and presented to a high precision that can be easily read by computer codes written in any computer language, e.g., C, C++, and FORTRAN. EPICS includes four separate data bases that are designed to be used in combination, these include, • The Evaluated Electron Data Library (EEDL), to describe the interaction of electrons with matter. • The Evaluated Photon Data Library (EPDL), to describe the interaction of photons with matter. • The Evaluated Atomic Data Library (EADL), to describe the emission of electrons and photons back to neutrality following an ionizing event, caused by either electron or photon interactions. • The Evaluated Excitation Data Library (EXDL), to describe the excitation of atoms due to photon interaction. All of these are available in the Extended ENDL format (ENDLX) in which the evaluations were originally performed. The first three are also available in the ENDF format; as yet ENDF does not include formats to handle excitation data (EXDL).« less

  19. Electron Photon Interaction Cross Sections

    SciTech Connect

    Cullen, D. E.

    2014-11-01

    Version 00 The Electron Photon Interaction Cross Sections, EPICS, provides the atomic data needed to perform coupled Electron-Photon transport calculations, to produce accurate macroscopic results, such as energy deposit and dose. Atomic data is provided for elements, Z = 1 to 100, over the energy range 10 eV to 100 GeV; note that nuclear data, such as photo-nuclear, and data for compounds, are not included. All data is in a simple computer independent text format that is standard and presented to a high precision that can be easily read by computer codes written in any computer language, e.g., C, C++, and FORTRAN. EPICS includes four separate data bases that are designed to be used in combination, these include, • The Evaluated Electron Data Library (EEDL), to describe the interaction of electrons with matter. • The Evaluated Photon Data Library (EPDL), to describe the interaction of photons with matter. • The Evaluated Atomic Data Library (EADL), to describe the emission of electrons and photons back to neutrality following an ionizing event, caused by either electron or photon interactions. • The Evaluated Excitation Data Library (EXDL), to describe the excitation of atoms due to photon interaction. All of these are available in the Extended ENDL format (ENDLX) in which the evaluations were originally performed. The first three are also available in the ENDF format; as yet ENDF does not include formats to handle excitation data (EXDL).

  20. [Fast neutron cross section measurements

    SciTech Connect

    Knoll, G.F.

    1992-10-26

    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.

  1. Experimental nuclear cross sections for spacecraft shield analysis

    NASA Technical Reports Server (NTRS)

    Peelle, R. W.

    1972-01-01

    Experiments have been performed to validate and to supplement the intranuclear cascade model as a method for estimating cross sections of importance to spacecraft shield design. The experimental situation is inconclusive particularly for neutron-producing reactions, but is relatively sound for reaction cross sections and for proton spectra at several hundred MeV at medium forward angles. Secondary photon contributions are imprecisely known.

  2. Separation of the Longitudinal and Transverse Cross Sections in the p(e,e{prime}K{sup +}){Lambda} and p(e,e{prime}K{sup +}){Sigma}{sup 0} Reactions

    SciTech Connect

    R.M. Mohring; David Abbott; Abdellah Ahmidouch; T.A. Amatuni; Pawel Ambrozewicz; Tatiana Angelescu; Christopher Armstrong; John Arrington; Ketevi Assamagan; Steven Avery; Kevin Bailey; Kevin Beard; S. Beedoe; Elizabeth Beise; Herbert Breuer; Roger Carlini; Jinseok Cha; C. Chang; Nicholas Chant; Evaristo Cisbani; Glenn Collins; William Cummings; Samuel Danagoulian; Raffaele De Leo; Fraser Duncan; James Dunne; Dipangkar Dutta; T. Eden; Rolf Ent; Laurent Eyraud; Lars Ewell; John Finn; H. Terry Fortune; Valera Frolov; Salvatore Frullani; Christophe Furget; Franco Garibaldi; David Gaskell; Don Geesaman; Paul Gueye; Kenneth Gustafsson; Jens-ole Hansen; Mark Harvey; Wendy Hinton; Ed Hungerford; Mauro Iodice; C. Jackson; Cynthia Keppel; Wooyoung Kim; Kouichi Kino; Douglas Koltenuk; Serge Kox; Laird Kramer; Antonio Leone; Allison Lung; David Mack; Richard Madey; M. Maeda; Stanislaw Majewski; Pete Markowitz; T. MART; C.J. Martoff; David Meekins; A. Mihul; Joseph Mitchell; Hamlet Mkrtchyan; Sekazi Mtingwa; Maria-Ioana Niculescu; R. Perrino; David Potterveld; John Price; Brian Raue; Jean-Sebastien Real; Joerg Reinhold; Philip Roos; Teijiro Saito; Geoff Savage; Reyad Sawafta; Ralph Segel; Samuel Stepanyan; Paul Stoler; Vardan Tadevosyan; Liguang Tang; Liliana Teodorescu; Tatsuo Terasawa; Hiroaki Tsubota; Guido Urciuoli; Jochen Volmer; William Vulcan; T. Welch; Robert Williams; Stephen Wood; Chen Yan; Benjamin Zeidman

    2003-05-01

    We report measurements of cross sections for the reaction p(e,e{prime}K{sup +})Y, for both the Lambda and Sigma{sub 0} hyperon states, at an invariant mass of W = 1.84 GeV and four-momentum transfers 0.5 < Q{sup 2} < 2 (GeV/c){sup 2}. Data were taken for three values of virtual photon polarization, allowing the decomposition of the cross sections into longitudinal and transverse components. The Lambda data is a revised analysis of prior work, whereas the Sigma{sub 0} results have not been previously reported.

  3. Separation of the longitudinal and transverse cross sections in the {sup 1}H(e,e{prime} K{sup +}){Lambda} and {sup 1}H(e,e{prime} K{sup +}){Sigma}{sup 0} reactions

    SciTech Connect

    R.M. Mohring; David Abbott; Abdellah Ahmidouch; Thomas Amatuni; Pawel Ambrozewicz; Tatiana Angelescu; Christopher Armstrong; John Arrington; Ketevi Assamagan; Steven Avery; Kevin Bailey; Kevin Beard; S Beedoe; Elizabeth Beise; Herbert Breuer; Roger Carlini; Jinseok Cha; C. Chang; Nicholas Chant; Evaristo Cisbani; Glenn Collins; William Cummings; Samuel Danagoulian; Raffaele De Leo; Fraser Duncan; James Dunne; Dipangkar Dutta; T Eden; Rolf Ent; Laurent Eyraud; Lars Ewell; John Finn; H. Terry Fortune; Valera Frolov; Salvatore Frullani; Christophe Furget; Franco Garibaldi; David Gaskell; Donald Geesaman; Paul Gueye; Kenneth Gustafsson; Jens-Ole Hansen; Mark Harvey; Wendy Hinton; Ed Hungerford; Mauro Iodice; Ceasar Jackson; Cynthia Keppel; Wooyoung Kim; Kouichi Kino; Douglas Koltenuk; Serge Kox; Laird Kramer; Antonio Leone; Allison Lung; David Mack; Richard Madey; M Maeda; Stanislaw Majewski; Pete Markowitz; T Mart; C Martoff; David Meekins; A. Mihul; Joseph Mitchell; Hamlet Mkrtchyan; Sekazi Mtingwa; Maria-Ioana Niculescu; R. Perrino; David Potterveld; John Price; Brian Raue; Jean Sebastien Real; Joerg Reinhold; Philip Roos; Teijiro Saito; Geoff Savage; Reyad Sawafta; Ralph Segel; Stepan Stepanyan; Paul Stoler; Vardan Tadevosyan; Liguang Tang; Liliana Teodorescu; Tatsuo Terasawa; Hiroaki Tsubota; Guido Urciuoli; Jochen Volmer; William Vulcan; T. Welch; Robert Williams; Stephen Wood; Chen Yan; Benjamin Zeidman

    2003-05-19

    We report measurements of cross sections for the reaction {sup 1}H(e,e{prime} K{sup +})Y, for both the {Lambda} and {Sigma}{sup 0} hyperon states, at an invariant mass of W = 1.84 GeV and four-momentum transfers 0.5 < Q{sup 2} < 2 (GeV/c){sup 2}. Data were taken for three values of virtual photon polarization {epsilon}, allowing the decomposition of the cross sections into longitudinal and transverse components. The {Lambda} data are a revised analysis of prior work, whereas the {Sigma}{sup 0} results have not been previously reported.

  4. A Comparison of Longitudinal and Transverse Cross Sections in the p (e,e'K)/Lambda and p(e,e'K)/Sigma Reactions

    SciTech Connect

    Richard Mohring

    1999-10-01

    Jefferson Lab Experiment E93-018 measured kaon electroproduction in hydrogen in two hyperon channels, p(e, e'K{sup +})Lambda and p(e,e'K{sup +})Sigma{sup 0}. Data in both channels were taken at three (3) different values of the virtual photon transverse linear polarization, epsilon, for each of four (4) values of Q{sup 2} = (0.52, 0.75, 1.00, 2.00) GeV{sup 2}. Cross sections averaged over the azimuthal angle, phi, were extracted (i.e., sigma{sub T} + epsilon sigma{sub L}) at each of these twelve points for each hyperon. Rosenbluth separations were performed to separate the longitudinal and transverse production cross sections.

  5. Elastic Scattering and Total Cross-Section in p+p Reactions --As Measured by the LHC Experiment TOTEM at √{s} = 7 TeV--

    NASA Astrophysics Data System (ADS)

    Csörgő, T.; Antchev, G.; Aspell, P.; Atanassov, I.; Avati, V.; Baechler, J.; Berardi, V.; Berretti, M.; Bossini, E.; Bozzo, M.; Brogi, P.; Brücken, E.; Buzzo, A.; Cafagna, F. S.; Calicchio, M.; Catanesi, M. G.; Covault, C.; Csanád, M.; Deile, M.; Dimovasili, E.; Doubek, M.; Eggert, K.; Eremin, V.; Ferretti, R.; Ferro, F.; Fiergolski, A.; Garcia, F.; Giani, S.; Greco, V.; Grzanka, L.; Heino, J.; Hilden, T.; Intonti, M. R.; Janda, M.; Kašpar, J.; Kopal, J.; Kundrát, V.; Kurvinen, K.; Lami, S.; Latino, G.; Lauhakangas, R.; Leszko, T.; Lippmaa, E.; Lokajíček, M.; Lo Vetere, M.; Lucas Rodríguez, F.; Macrí, M.; Magaletti, L.; Magazzù, G.; Mercadante, A.; Meucci, M.; Minutoli, S.; Nemes, F.; Niewiadomski, H.; Noschis, E.; Novák, T.; Oliveri, E.; Oljemark, F.; Orava, R.; Oriunno, M.; Österberg, K.; Palazzi, P.; Perrot, A.-L.; Pedreschi, E.; PetäJäjärvi, J.; Procházka, J.; Quinto, M.; Radermacher, E.; Radicioni, E.; Ravotti, F.; Robutti, E.; Ropelewski, L.; Ruggiero, G.; Saarikko, H.; Sanguinetti, G.; Santroni, A.; Scribano, A.; Sette, G.; Snoeys, W.; Spinella, F.; Sziklai, J.; Taylor, C.; Turini, N.; Vacek, V.; Vítek, M.; Welti, J.; Whitmore, J.; Totem Collaboration

    Proton-proton elastic scattering has been measured by the TOTEMexperiment at the CERN Large Hadron Collider at √{s} = 7 TeV in special runs with the Roman Pot detectors placed as close to the outgoing beam as seven times the transverse beam size. The differential cross-section measurements are reported in the |t|-range of 0.36 to 2.5 GeV^{2}. Extending the range of data to low t values from 0.02 to 0.33 GeV^2, and utilizing the luminosity measurements of CMS, the total proton-proton cross section at √{s} = 7 TeV is measured to be (98.3 ± 0.2^{stat} ± 2.8^{syst}) mb.

  6. A proposed direct measurement of cross section at Gamow window for key reaction 19F(p,α) 16O in Asymptotic Giant Branch stars with a planned accelerator in CJPL

    NASA Astrophysics Data System (ADS)

    He, JianJun; Xu, ShiWei; Ma, ShaoBo; Hu, Jun; Zhang, LiYong; Fu, ChangBo; Zhang, NingTao; Lian, Gang; Su, Jun; Li, YunJu; Yan, ShengQuan; Shen, YangPing; Hou, SuQing; Jia, BaoLu; Zhang, Tao; Zhang, XiaoPeng; Guo, Bing; Kubono, Shigeru; Liu, WeiPing

    2016-05-01

    In 2014, the National Natural Science Foundation of China (NSFC) approved the Jinping Underground Nuclear Astrophysics laboratory (JUNA) project, which aims at direct cross-section measurements of four key stellar nuclear reactions right down to the Gamow windows. In order to solve the observed fluorine overabundances in Asymptotic Giant Branch (AGB) stars, measuring the key 19F(p,α)16O reaction at effective burning energies (i.e., at Gamow window) is established as one of the scientific research sub-projects. The present paper describes this sub-project in details, including motivation, status, experimental setup, yield and background estimation, aboveground test, as well as other relevant reactions.

  7. Documentation of Uncertainties in Experimental Cross Sections for EXFOR

    SciTech Connect

    Otuka, N.; Smith, D.L.

    2014-06-15

    Documentation of uncertainties and covariances in experimental nuclear reaction cross sections has been assessed. Following consideration of the importance of covariances for nuclear data in various nuclear applications, and presentation of a simple numerical example to demonstrate this point, the minimum basic concepts (mean, covariance, standard derivation, partial uncertainties, micro- and macro-correlation coefficients) are introduced. A deterministic approach to propagating the covariances in primary measured parameters (e.g., counts) to the derived cross sections is discussed, using a neutron-induced activation cross section measurement as an example. Finally, various approaches to documentation (publication, compilation) of experimental cross sections to facilitate their use in future evaluations are mentioned.

  8. Neutron cross section standards and instrumentation

    NASA Astrophysics Data System (ADS)

    1992-09-01

    This report from the National Institute of Standards and Technology contains a summary of the accomplishments of the Neutron Cross Section Standards and Instrumentation Project during the second year of a three-year interagency agreement. This program includes a broad range of data measurements and evaluations. An emphasis has been focused on the (sup 10)B cross sections where serious discrepancies in the nuclear data base remain. In particular, there are important problems with the interpretation of the helium gas production associated with diagnostic measurements of interest in nuclear technology. The enhanced use of this isotope for medical treatment is also of significance. New measurements of neutron reaction cross sections for (sup 10)B are in progress in collaboration with scientists at the Oak Ridge National Laboratory. New experiments are in progress on the important dosimetry standards (sup 237)Np(n,f) and (sup 239)Pu(n,f) below 1 MeV neutron energy. In addition, new measurements of charged-particle production in basic biological elements for medical applications are underway. Further measurements are planned or in progress in collaborations which include fission fragment energy and angular distributions, and neutron energy spectra and angular distributions from neutron-induced fission. Also measurements of angular distributions of neutrons from scattering on protons, and determinations of capture cross section of gold are planned for a later time. Data evaluation will shift to include a unified international effort to motivate new measurements and evaluations. In response to the requests of the measurement community, NIST is beginning the formation of a national depository for fissionable isotope mass standards. This action will preserve for future measurements the valuable and irreplaceable critical samples whose masses and composition have been carefully determined and documented over the past 30 years of the nuclear program.

  9. SNL RML recommended dosimetry cross section compendium

    SciTech Connect

    Griffin, P.J.; Kelly, J.G.; Luera, T.F.; VanDenburg, J.

    1993-11-01

    A compendium of dosimetry cross sections is presented for use in the characterization of fission reactor spectrum and fluence. The contents of this cross section library are based upon the ENDF/B-VI and IRDF-90 cross section libraries and are recommended as a replacement for the DOSCROS84 multigroup library that is widely used by the dosimetry community. Documentation is provided on the rationale for the choice of the cross sections selected for inclusion in this library and on the uncertainty and variation in cross sections presented by state-of-the-art evaluations.

  10. Critical Evaluation of Chemical Reaction Rates and Collision Cross Sections of Importance in the Earth's Upper Atmosphere and the Atmospheres of Other Planets, Moons, and Comets

    NASA Technical Reports Server (NTRS)

    Huestis, David L.

    2006-01-01

    We propose to establish a long-term program of critical evaluation by domain experts of the rates and cross sections for atomic and molecular processes that are needed for understanding and modeling the atmospheres in the solar system. We envision data products resembling those of the JPL/NASA Panel for Data Evaluation and the similar efforts of the international combustion modeling community funded by US DoE and its European counterpart.

  11. Measurement of the 115In(n,γ)116 m In reaction cross-section at the neutron energies of 1.12, 2.12, 3.12 and 4.12 MeV

    NASA Astrophysics Data System (ADS)

    Lawriniang, Bioletty Mary; Badwar, Sylvia; Ghosh, Reetuparna; Jyrwa, Betylda; Vansola, Vibha; Naik, Haladhara; Goswami, Ashok; Naik, Yeshwant; Datrik, Chandra Shekhar; Gupta, Amit Kumar; Singh, Vijay Pal; Pol, Sudir Shibaji; Subramanyam, Nagaraju Balabenkata; Agarwal, Arun; Singh, Pitambar

    2015-08-01

    The 115In(n,γ)116 m In reaction cross section at neutron energies of 1.12, 2.12, 3.12 and 4.12 MeV was determined by using an activation and off-line γ-ray spectrometric technique. The monoenergetic neutron energies of 1.12 - 4.12 MeV were generated from the 7Li(p,n) reaction by using proton beam with energies of 3 and 4 MeV from the folded tandem ion beam accelerator (FOTIA) at Bhabha Atomic Research Centre (BARC) and with energies of 5 and 6 MeV from the Pelletron facility at Tata Institute of Fundamental Research (TIFR), Mumbai. The 197Au(n,γ)198Au reaction cross-section was used as the neutron flux monitor.The 115In(n,γ)116 m In reaction cross section at neutron energies of 1.12, 2.12, 3.12 and 4.12 MeV was determined by using an activation and off-line γ-ray spectrometric technique. The monoenergetic neutron energies of 1.12 - 4.12 MeV were generated from the 7Li(p,n) reaction by using proton beam with energies of 3 and 4 MeV from the folded tandem ion beam accelerator (FOTIA) at Bhabha Atomic Research Centre (BARC) and with energies of 5 and 6 MeV from the Pelletron facility at Tata Institute of Fundamental Research (TIFR), Mumbai. The 197Au(n,γ)198 Au reaction cross-section was used as the neutron flux monitor. The 115In(n,γ)116 m In reaction cross-sections at neutron energies of 1.12 - 4.12 MeV were compared with the literature data and were found to be in good agreement with one set of data, but not with others. The 115In(n,γ)116 m In cross-section was also calculated theoretically by using the computer code TALYS 1.6 and was found to be slightly lower than the experimental data from the present work and the literature.)198Au reaction cross-section was used as the neutron flux monitor. The 115In(n,γ)116 m In reaction cross-sections at neutron energies of 1.12 - 4.12 MeV were compared with the literature data and were found to be in good agreement with one set of data, but not with others. The 115In(n,γ)116 m In cross-section was also calculated

  12. Neutronic Cross Section Calculations on Fluorine Nucleus

    NASA Astrophysics Data System (ADS)

    Kara, A.; Tel, E.

    2013-06-01

    Certain light nuclei such as Lithium (Li), Beryllium (Be), Fluorine (F) (which are known as FLİBE) and its molten salt compounds (LiF, BeF2 and NaF) can serve as a coolant which can be used at high temperatures without reaching a high vapor pressure. These molten salt compounds are also a good neutron moderator. In this study, cross sections of neutron induced reactions have been calculated for fluorine target nucleus. The new calculations on the excitation functions of 19F( n, 2n), 19F( n, p), 19F( n, xn), 19F( n, xp) have been made. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve the full exciton model and the cascade exciton model. The equilibrium effects are calculated according to the Weisskopf-Ewing model. Also in the present work, the ( n, 2n) and ( n, p) reaction cross sections have calculated by using evaluated empirical formulas developed by Tel et al. at 14-15 MeV energy. The multiple pre-equilibrium mean free path constant from internal transition have been investigated for 19F nucleus. The obtained results have been discussed and compared with the available experimental data.

  13. Cross Sections: No 6 Hold Section at Fr 178 Looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Cross Sections: No 6 Hold Section at Fr 178 Looking Fwd, No 7 Hold Section at No 154 Looking Fwd, No 7 Hold Section at Fr 195 Looking Fwd Showing Trans 194, No 7 Hold Section at Fr 198 Looking Fwd - General John Pope, Suisun Bay Reserve Fleet, Benicia, Solano County, CA

  14. Cross sections of the reaction {sup 231}Pa(d,3n){sup 230}U for the production of {sup 230}U/{sup 226}Th for targeted {alpha} therapy

    SciTech Connect

    Morgenstern, A.; Bruchertseifer, F.; Zielinska, B.; Apostolidis, C.; Lebeda, O.; Stursa, J.; Capote, R.; Sin, M.

    2009-11-15

    {sup 230}U and its daughter nuclide {sup 226}Th are novel therapeutic nuclides for application in targeted {alpha} therapy of cancer. We investigated the feasibility of producing {sup 230}U/{sup 226}Th via deuteron irradiation of {sup 231}Pa according to the reaction {sup 231}Pa(d,3n){sup 230}U. The experimental excitation function for a deuteron-induced reaction on {sup 231}Pa is reported for the first time. Cross sections were measured using thin targets of {sup 231}Pa prepared by electrodeposition and {sup 230}U yields were analysed using {alpha} spectrometry. Beam energies were calculated from measured beam orbits and compared with the values obtained via monitor reactions on aluminium foils using high-resolution {gamma} spectrometry and IAEA recommended cross sections. Beam intensities were determined using a beam current integrator. The experimental cross sections are in excellent agreement with model calculations allowing for deuteron breakup using the EMPIRE 3 code. According to thick-target yields calculated from the experimental excitation function, the reaction {sup 231}Pa(d,3n){sup 230}U allows the production of {sup 230}U/{sup 226}Th at moderate levels.

  15. Measurements of double-differential cross sections of charged-particle emission reactions for several structural elements of fusion power reactors by 14.1-MeV incident neutrons

    SciTech Connect

    Kokooo; Murata, Isao; Takahashi, Akito

    1999-05-01

    A two-dimensional energy and time-of-flight charged-particle spectrometer has been developed and used to measure the double-differential cross-section (DDX) data of (n,xp) and (n,x{alpha}) reactions for several elements with 14.1-MeV incident neutrons at OKTAVIAN, the Intense 14-MeV Neutron Source Facility of Osaka University. The DDX data of the {sup 51}V(n, xp), {sup 51}V(n, x{alpha}), {sup nat}Fe(n, xp), {sup nat}Fe(n,x{alpha}), {sup 59}Co(n, xp), {sup 59}Co(n, x{alpha}), {sup nat}Ni(n, x{alpha}), {sup nat}Cu(n, x{alpha}), {sup 93}Nb(n, xp), {sup 93}Nb(n, x{alpha}), and {sup nat}Mo(n, xp) reactions are measured. The angle-integrated energy differential cross-section (EDX) data were deduced from the measured DDX data and compared with other experimental results [except for the {sup 59}Co(n, xp) reaction] and evaluated nuclear data of JENDL fusion file (JENDL-FF). A comparison was also done with the ENDF/B-VI for the total reaction cross sections of all measured reactions except for the {sup nat}Mo(n, xp) reaction and the EDX of the {sup nat}Ni(n, x{alpha}) and {sup nat}Cu(n, x{alpha}) reactions. The theoretical calculations were done by using the SINCROS-II code. The measured data agreed fairly well with other data for almost all the reactions. the JENDL-FF and SINCROS-II data underestimate the measured EDX data for the reactions of {sup 93}Nb(n, x{alpha}) and {sup nat}Mo(n, xp). For the {sup nat}Fe(n, xp), {sup nat}Fe(n, x{alpha}), {sup 59}Co(n, x{alpha}), and {sup nat}Ni(n, x{alpha}) reactions, smaller data are given than other data, i.e., other experimental data, JENDL-FF, and ENDF/B-VI. The SINCROS-II code can reproduce well for both the proton and alpha-particle emission cross-section values.

  16. New measurement of the 10B(p,α0)7Be reaction cross section at low energies and the structure of 11C

    NASA Astrophysics Data System (ADS)

    Lombardo, I.; Dell'Aquila, D.; Conte, F.; Francalanza, L.; La Cognata, M.; Lamia, L.; La Torre, R.; Spadaccini, G.; Spitaleri, C.; Vigilante, M.

    2016-05-01

    We report preliminary results of a new measurement of the 10B(p,α0)7Be cross section in the 0.6 - 1.0 MeV bombarding energy domain. In this region very few data have been reported in the literature. Excitation functions at both forward and backward angles have been obtained. Angular distributions testify the contribution due to several excited states in the 11C compound nucleus. The experimental S-factor is about 30% lower than the one reported in the literature and based on activation methods.

  17. Measurements of the Total Reaction Cross Sections for 6,8He and 8,9Li Nuclei with Energies of (25-45)A Mev on natAl, natTa and natPb

    NASA Astrophysics Data System (ADS)

    Erdemchimeg, B.; Artukh, A. G.; Klygin, S. A.; Kononenko, G. A.; Kyslukha, D. A.; Sereda, Yu. M.; Vorontzov, A. N.; Lukyanov, S. M.; Penionzhkevich, Yu. E.; Davaa, S.; Khuukhenkhuu, G.; Borcea, C.; Rotaru, F.; Stanoiu, M.; Martina, L.; Saillant, F.; Raine, B.

    2015-06-01

    The total nuclear reaction cross sections (σR) measurements have long been of interest since they tell us about the radii and transparency of these nuclei and give clues to understanding of their structure. For studies of unstable nuclei, in particular the physical properties of halo nuclei and the neutron skin thickness, it is valuable to know not only the root-mean-square radii (rms) but it is important to know the details of nucleusnucleus potentials. Our goal was to study total reaction cross sections (σR) by a direct measurement technique (the so-called beam attenuation or transmission method) which allows to extract model independent information. The interaction radii for 6He, 8,9Li were extracted, which are in agreement with the previous measurement at the similar energies (about a few tens of AMeV) Our results show a tendency of increasing radii as function of mass of the secondary targets.

  18. Vertically stabilized elongated cross-section tokamak

    DOEpatents

    Sheffield, George V.

    1977-01-01

    This invention provides a vertically stabilized, non-circular (minor) cross-section, toroidal plasma column characterized by an external separatrix. To this end, a specific poloidal coil means is added outside a toroidal plasma column containing an endless plasma current in a tokamak to produce a rectangular cross-section plasma column along the equilibrium axis of the plasma column. By elongating the spacing between the poloidal coil means the plasma cross-section is vertically elongated, while maintaining vertical stability, efficiently to increase the poloidal flux in linear proportion to the plasma cross-section height to achieve a much greater plasma volume than could be achieved with the heretofore known round cross-section plasma columns. Also, vertical stability is enhanced over an elliptical cross-section plasma column, and poloidal magnetic divertors are achieved.

  19. Cross Sections for Electron Collisions with Methane

    SciTech Connect

    Song, Mi-Young Yoon, Jung-Sik; Cho, Hyuck; Itikawa, Yukikazu; Karwasz, Grzegorz P.; Kokoouline, Viatcheslav; Nakamura, Yoshiharu; Tennyson, Jonathan

    2015-06-15

    Cross section data are compiled from the literature for electron collisions with methane (CH{sub 4}) molecules. Cross sections are collected and reviewed for total scattering, elastic scattering, momentum transfer, excitations of rotational and vibrational states, dissociation, ionization, and dissociative attachment. The data derived from swarm experiments are also considered. For each of these processes, the recommended values of the cross sections are presented. The literature has been surveyed through early 2014.

  20. Theoretical antideuteron-nucleus absorptive cross sections

    NASA Technical Reports Server (NTRS)

    Buck, W. W.; Norbury, J. W.; Townsend, L. W.; Wilson, J. W.

    1993-01-01

    Antideuteron-nucleus absorptive cross sections for intermediate to high energies are calculated using an ion-ion optical model. Good agreement with experiment (within 15 percent) is obtained in this same model for (bar p)-nucleus cross sections at laboratory energies up to 15 GeV. We describe a technique for estimating antinucleus-nucleus cross sections from NN data and suggest that further cosmic ray studies to search for antideuterons and other antinuclei be undertaken.

  1. Annular-Cross-Section CFE Chamber

    NASA Technical Reports Server (NTRS)

    Sharnez, Rizwan; Sammons, David W.

    1994-01-01

    Proposed continuous-flow-electrophoresis (CFE) chamber of annular cross section offers advantages over conventional CFE chamber, and wedge-cross-section chamber described in "Increasing Sensitivity in Continuous-Flow Electrophoresis" (MFS-26176). In comparison with wedge-shaped chamber, chamber of annular cross section virtually eliminates such wall effects as electro-osmosis and transverse gradients of velocity. Sensitivity enhanced by incorporating gradient maker and radial (collateral) flow.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  3. Cross sections for {sup 238}U(n,n{sup '}{gamma}) and {sup 238}U(n,2n{gamma}) reactions at incident neutron energies between 5 and 14 MeV

    SciTech Connect

    Hutcheson, A.; Crowell, A. S.; Fallin, B.; Howell, C. R.; Kwan, E.; Tonchev, A. P.; Tornow, W.; Angell, C.; Karwowski, H. J.; Becker, J. A.; Macri, R. A.; Dashdorj, D.; Fotiades, N.; Kawano, T.; Nelson, R. O.; Kelley, J. H.; Pedroni, R. S.

    2009-07-15

    Precision measurements of {sup 238}U(n,n{sup '}{gamma}) and {sup 238}U(n,2n{gamma}) partial cross sections have been performed at Triangle Universities Nuclear Laboratory (TUNL) to improve crucial data needed for testing nuclear reaction models in the actinide mass region. A pulsed and monoenergetic neutron beam was used in combination with high-resolution {gamma}-ray spectroscopy to obtain partial cross sections for incident neutron energies between 5 and 14 MeV. {gamma}-ray yields were measured with high-purity germanium clover and planar detectors. Measured partial cross-section data are compared with previous results using white and monoenergetic neutron beams and calculations from the GNASH and TALYS Hauser-Feshbach statistical-model codes. Present experimental results are in fair to good agreement with most of the existing data for the {sup 238}U(n,n{sup '}{gamma}) reaction. However, significant discrepancies are observed for the {sup 238}U(n,2n{gamma}) reaction.

  4. Particle Leaking, Cross-Section Ratio 10B(n,{alpha})/238U(n,fission), and Excitation Function of the Reaction 10B(n,{alpha})7Li at MeV Energies

    SciTech Connect

    Giorginis, Georgios; Khryachkov, Vitali

    2005-05-24

    The 10B(n,{alpha})7Li reaction was studied in the energy range between 1.5 MeV and 5.6 MeV at the 7-MV Van de Graaff accelerator of IRMM by using a gridded ionisation chamber, signal digitisation, and an intrinsic 238U neutron monitor. The aim was to obtain accurate data for the IAEA Coordinated Research Project (CRP) on the improvement of standard cross sections for light elements. The effect of particle leaking was discovered and its implications investigated. The determination of the cross section {sigma}({alpha}0+{alpha}1) strongly benefits from it but measurements of angular distributions, individual cross sections {sigma}({alpha}0) and {sigma}({alpha}1), and the branching ratio {alpha}0/{alpha}1 are negatively affected. The correct number of reaction events was obtained by identification of unknown particle signatures in the energy spectra as 10B(n,{alpha})7Li events in the form of quasi 7Li+{alpha} particles created by particle leaking. The cross-section ratio 10B(n,{alpha})7Li/238U(n,fission) was measured and the excitation function of 10B(n,{alpha})7Li determined by simultaneously detecting the charged particles from the boron disintegration in the forward hemisphere and the 238U fission fragments in the backward hemisphere. The IRMM cross sections are compared to experimental data of other groups and to predictions of the ENDF/B-VI.8, JENDL-3.3, and JEF-2.2 evaluations.

  5. State-to-state reactive differential cross sections for the H+H2-->H2+H reaction on five different potential energy surfaces employing a new quantum wavepacket computer code: DIFFREALWAVE.

    PubMed

    Hankel, Marlies; Smith, Sean C; Allan, Robert J; Gray, Stephen K; Balint-Kurti, Gabriel G

    2006-10-28

    State-to-state differential cross sections have been calculated for the hydrogen exchange reaction, H+H2-->H2+H, using five different high quality potential energy surfaces with the objective of examining the sensitivity of these detailed cross sections to the underlying potential energy surfaces. The calculations were performed using a new parallel computer code, DIFFREALWAVE. The code is based on the real wavepacket approach of Gray and Balint-Kurti [J. Chem. Phys. 108, 950 (1998)]. The calculations are parallelized over the helicity quantum number Omega' (i.e., the quantum number for the body-fixed z component of the total angular momentum) and wavepackets for each J,Omega' set are assigned to different processors, similar in spirit to the Coriolis-coupled processors approach of Goldfield and Gray [Comput. Phys. Commun. 84, 1 (1996)]. Calculations for J=0-24 have been performed to obtain converged state-to-state differential cross sections in the energy range from 0.4 to 1.2 eV. The calculations employ five different potential energy surfaces, the BKMP2 surface and a hierarchical family of four new ab initio surfaces [S. L. Mielke, et al., J. Chem. Phys. 116, 4142 (2002)]. This family of four surfaces has been calculated using three different hierarchical sets of basis functions and also an extrapolation to the complete basis set limit, the so called CCI surface. The CCI surface is the most accurate surface for the H3 system reported to date. Our calculations of differential cross sections are the first to be reported for the A2, A3, A4, and CCI surfaces. They show that there are some small differences in the cross sections obtained from the five different surfaces, particularly at higher energies. The calculations also show that the BKMP2 performs well and gives cross sections in very good agreement with the results from the CCI surface, displaying only small divergences at higher energies. PMID:17092069

  6. Cross sections of projectile-like fragments in the reaction {sup 19}F+{sup 66}Zn in the beam energy range of 3-6 MeV/nucleon

    SciTech Connect

    Tripathi, R.; Sudarshan, K.; Sodaye, S.; Reddy, A. V. R.; Goswami, A.; Sharma, S. K.; Nayak, B. K.

    2009-06-15

    Angular distributions of projectile-like fragments (PLFs) have been measured in the reaction {sup 19}F+{sup 66}Zn at E{sub lab}=61,82,92, and 109 MeV to understand their formation in the low energy domain (< or approx. 7 MeV nucleon). In this energy range, maximum angular momentum 'l{sub max}' in the reaction is lower than or close to the critical or limiting angular momentum for complete fusion 'l{sub lim}(CF).' The sum-rule model was modified to explain the cross sections of PLFs in the present study. For the first time, the modified sum-rule model, with a competition of incomplete fusion (ICF) reaction with complete fusion below l{sub lim}(CF) reasonably reproduced the cross sections of PLFs in the beam energy range of the present study. It was observed that the cross sections of lighter PLFs fall more rapidly with decreasing beam energy compared to those of heavier PLFs, suggesting a change in the reaction mechanism from heavier to lighter PLFs. Transfer probabilities for peripheral collisions were calculated within the framework of a semiclassical formalism. The parameters of the nuclear potential required for the calculation of transfer probability were obtained by fitting the elastic scattering data measured in the present work. Calculated transfer probabilities were significantly lower compared to the corresponding experimental values, suggesting a significant overlap of the projectile and the target nuclei in incomplete fusion reactions. The present analysis showed that the overlap of the projectile and the target nuclei increases with increasing mass transfer at a given beam energy and for a given PLF, overlap increases with increasing beam energy.

  7. Absolute partial photoionization cross sections of ozone.

    SciTech Connect

    Berkowitz, J.; Chemistry

    2008-04-01

    Despite the current concerns about ozone, absolute partial photoionization cross sections for this molecule in the vacuum ultraviolet (valence) region have been unavailable. By eclectic re-evaluation of old/new data and plausible assumptions, such cross sections have been assembled to fill this void.

  8. Neutrino flux predictions for cross section measurements

    SciTech Connect

    Hartz, Mark

    2015-05-15

    Experiments that measure neutrino interaction cross sections using accelerator neutrino sources require a prediction of the neutrino flux to extract the interaction cross section from the measured neutrino interaction rate. This article summarizes methods of estimating the neutrino flux using in-situ and ex-situ measurements. The application of these methods by current and recent experiments is discussed.

  9. Activation cross sections for 190Os( n, p) 190m,gRe, 188Os( n, p) 188Re and 190Os( n, n') 190mOs reactions from 13.5 to 14.8 MeV

    NASA Astrophysics Data System (ADS)

    Luo, Junhua; Zhang, Zhirong; Tian, Weisong; Tuo, Fei; Kong, Xiangzhong; Liu, Rong; Jiang, Li

    2009-04-01

    Cross sections for ( n, p) and ( n, n') reactions have been measured on osmium isotopes at the neutron energies from 13.5 to 14.8 MeV using the activation technique in combination with high-resolution gamma-ray spectroscopy. Neutrons were produced via the 3H( d, n) 4He reaction using solid TiT. The neutron fluences were determined using the monitor reaction 93Nb( n,2 n) 92mNb. Data are reported for the following reactions: 190Os( n, p) 190mRe, 190Os( n, p) 190gRe, 190Os( n, p) 190Re, 188Os( n, p) 188Re and 190Os( n, n') 190mOs. Nuclear model calculations using the code HFTT, which employs the Hauser-Feshbach (statistical model) and exciton model (precompound effects) formalisms, were undertaken to describe the formation of the products. The cross sections were discussed and compared with experimental data found in the literature, with values of model calculations including the pre-equilibrium contribution, and with evaluation data of JEFF-3.1/A.

  10. Measurements of the cross section for the (182)W(n,p)(182(m+g))Ta and (184)(n,p)(184)Ta reactions in the 14MeV energy range using the activation technique.

    PubMed

    Song, Yueli; Zhou, Fengqun; Tian, Mingli; Li, Yong; Yuan, Shuqing; Lan, Changlin

    2015-04-01

    The cross section for the (182)W(n,p)(182(m+g))Ta and (184)W(n,p)(184)Ta reactions has been measured in the neutron energy range of 13.5-14.7MeV using the activation technique and a coaxial HPGe γ-ray detector. In our experiment, the fast neutrons were produced by the T(d,n)(4)He reaction at the ZF-300-II Intense Neutron Generator at Lanzhou University. Natural wolfram foils of 99.9% purity were used as target materials. The neutron flux was determined using the monitor reaction (93)Nb(n,2n)(92m)Nb and the neutron energies were determined using the method of cross-section ratio measurements employing the (90)Zr(n,2n)(89)Zr to (93)Nb(n,2n)(92m)Nb reactions. The results of this work are compared with experimental data found in the literature and the estimates obtained from a published empirical formula based on the statistical model with Q-value dependence and odd-even effects taken into consideration. PMID:25617709

  11. Communication: Rovibrationally selected absolute total cross sections for the reaction H2O+(X2B1; v1+v2+v3+ = 000; N+Ka+Kc+) + D2: Observation of the rotational enhancement effect

    NASA Astrophysics Data System (ADS)

    Xu, Yuntao; Xiong, Bo; Chang, Yih Chung; Ng, C. Y.

    2012-12-01

    By employing the newly established vacuum ultraviolet laser pulsed field ionization-photoion (PFI-PI) double quadrupole-double octopole ion guide apparatus, we have measured the rovibrationally selected absolute total cross sections of the ion-molecule reaction H2O+(X2B1; v1+v2+v3+ = 000; N+Ka+Kc+) + D2 → H2DO+ + D in the center-of-mass collision energy (Ecm) range of 0.05-10.00 eV. The pulsing scheme used for the generation of PFI-PIs has made possible the preparation of reactant H2O+(X2B1; v1+v2+v3+ = 000) ions in single N+Ka+Kc+ rotational levels with high kinetic energy resolutions. The absolute total cross sections observed in different N+Ka+Kc+ levels with rotational energies in the range of 0-200 cm-1 were found to exhibit a significant rotational enhancement on the reactivity for the titled reaction. In contrast, the measured cross sections reveal a decreasing trend with increasing Ecm, indicating that the rotational enhancement observed is not a total energy effect, but a dynamical effect. Furthermore, the rotational enhancement is found to be more pronounced as Ecm is decreased. This experiment provided evidence that the coupling of the core rotational angular momentum with the orbital angular momentum could play a role in chemical reactivity, particularly at low Ecm.

  12. Cross sections for proton induced high energy γ -ray emission (PIGE) in reaction 19 F(p, αγ)16 O at incident proton energies between 1.5 and 4 MeV

    NASA Astrophysics Data System (ADS)

    Cabanelas, P.; Cruz, J.; Fonseca, M.; Henriques, A.; Lourenço, F.; Luís, H.; Machado, J.; Pires Ribeiro, J.; Sánchez-Benítez, A. M.; Teubig, P.; Velho, P.; Zarza-Moreno, M.; Galaviz, D.; Jesus, A. P.

    2016-08-01

    We have studied the high energy gamma-rays produced in the reaction 19 F(p, αγ)16 O for incident proton energies from 1.5 to 4.0 MeV over NaF/Ag and CaF2/Ag thin targets in two different sets of data. Gamma-rays were detected with a High Purity Ge detector with an angle of 130° with respect to the beam axis. The cross-sections for the high energy gamma-rays of 6.129, 6.915 and 7.115 MeV have been measured for the whole group between 5 and 7.2 MeV with accuracy better than 10%. A new energy range was covered and more points are included in the cross-sections data base expanding the existing set of data. Results are in agreement with previous measurements in similar conditions.

  13. Experimental determination of the {sup 36}Cl(n,p){sup 36}S and {sup 36}Cl(n,{alpha}){sup 33}P reaction cross sections and the consequences on the origin of {sup 36}S

    SciTech Connect

    Smet, L. de; Wagemans, C.; Goeminne, G.; Heyse, J.; Gils, J. van

    2007-03-15

    The {sup 36}Cl(n,p){sup 36}S and {sup 36}Cl(n,{alpha}){sup 33}P reaction cross sections have been studied with resonance neutrons at the linear accelerator GELINA of the IRMM in Geel (Belgium) and have been determined up to approximately 250 keV using the time-of-flight technique. In this energy region, 17 resonances were observed, whereas eight were identified before. For some resonances the resonance strength, the spin, and the total width could be determined. From the obtained cross section data, the MACS has been calculated by numerical integration. These updated MACS values were used in stellar models to trace the origin of the rare isotope {sup 36}S.

  14. Measurement of cross sections for the {sup 232}Th(P,4n){sup 229}Pa reaction at low proton energies

    SciTech Connect

    Jost, C. U.; Griswold, J. R.; Bruffey, S. H.; Mirzadeh, S.; Stracener, D. W.; Williams, C. L.

    2013-04-19

    The alpha-emitters {sup 225}Ac and {sup 213}Bi are of great interest for alpha-radioimmunotherapy which uses radioisotopes attached to cancer-seeking antibodies to efficiently treat various types of cancers. Both radioisotopes are daughters of the long-lived {sup 229}Th(t{sub 1/2} = 7880y). {sup 229}Th can be produced by proton irradiation of {sup 232}Th and {sup 230}Th, either directly or through production of isobars that beta-decay into {sup 229}Th. To obtain excitation functions, {sup 232}Th and {sup 230}Th have been irradiated at the On-Line Test Facility at the Holifield Radioactive Ion Beam Facility at ORNL. Benchmark tests conducted with Cu and Ni foils show very good agreement with literature results. The experiments with thorium targets were focused on the production of {sup 229}Pa and its daughter {sup 225}Ac from both {sup 232}Th and {sup 230}Th. Differential cross-sections for production of {sup 229}Pa and other Pa isotopes have been obtained.

  15. Too big to see: overlooked plasma-destroying reaction with cross section1012 times that for fusion necessitates redesign of ITER

    NASA Astrophysics Data System (ADS)

    Maglich, Bogdan; Scott, Dan; Hester, Tim; Calsec Collaboration

    2015-11-01

    Existence of charge transfer collisions (CT) was overlooked in ITER design although CT cross section, σCT ~ 109 b, is ~ 1012 times that for fusion, σDT ~ mb, at T = 10 KeV. CT de-confines plasma by neutralizing ions. Since σCT = 100 σIO, ion τCT ~ τE = 3x10-7 s <

  16. Nucleon-Nucleon Total Cross Section

    NASA Technical Reports Server (NTRS)

    Norbury, John W.

    2008-01-01

    The total proton-proton and neutron-proton cross sections currently used in the transport code HZETRN show significant disagreement with experiment in the GeV and EeV energy ranges. The GeV range is near the region of maximum cosmic ray intensity. It is therefore important to correct these cross sections, so that predictions of space radiation environments will be accurate. Parameterizations of nucleon-nucleon total cross sections are developed which are accurate over the entire energy range of the cosmic ray spectrum.

  17. Inelastic cross sections from gamma-ray measurements

    SciTech Connect

    Nelson, Ronald Owen

    2010-12-06

    Measurements of gamma rays following neutron induced reactions have been studied with the Germanium Array for Neutron-induced Excitations (GEANIE) at the Los Alamos Neutron Science Center (LANSCE) for many years. Gamma-ray excitation functions and coincidence studies provide insight into nuclear reaction mechanisms as well as expanding our knowledge of energy levels and gamma-rays. Samples studied with Ge detectors at LANSCE range from Be to Pu. Fe, Cr and Ti have been considered for use as reference cross sections. An overview of the measurements and efforts to create a reliable neutron-induced gamma-ray reference cross section will be presented.

  18. ACTIV87: Fast Neutron Activation Cross Section File

    Energy Science and Technology Software Center (ESTSC)

    1993-08-01

    4. HISTORICAL BACKGROUND AND INFORMATION ACTIV87 is a compilation of fast neutron induced activation reaction cross-sections. The compilation covers energies from threshold to 20 MeV and is based on evaluated data taken from other evaluated data libraries and individual evaluations. The majority of these evaluations were performed by using available experimental data. The aforementioned available experimental data were used in the selection of needed parameters for theoretical computations and for normalizing the results of suchmore » computations. Theoretical calculations were also used for interpolation and extrapolation of experimental cross-section data. All of the evaluated data curves were compared with experimental data that had been reported over the four year period preceding 1987. Only those cross-sections not in contradiction with experimental data that was current in 1987 were retained in the activation file, ACTIV87. In cases of several conflicting evaluations, that evaluation was chosen which best corresponded to the experimental data. A few evaluated curves were renormalized in accordance with the results of the latest precision measurements. 5. APPLICATION OF THE DATA 6. SOURCE AND SCOPE OF DATA The following libraries and individual files of evaluated neutron cross-section data were used for the selection of the activation cross-sections: the BOSPOR Library, the Activation File of the Evaluated Nuclear Data Library, the Evaluated Neutron Data File (ENDF/B-V) Activation File, the International Reactor Dosimetry File (IRDF-82), and individual evaluations carried out under various IAEA research contracts. The file of selected reactions contains 206 evaluated cross-section curves of the (n,2n), (n,p) and (n,a) reactions which lead to radioactive products and may be used in many practical applications of neutron activation analysis. Some competing activation reactions, usually with low cross-section values, are given for completeness.« less

  19. Thermal neutron capture cross sections for the 152Sm(n,γ) 153Sm and 154Sm(n,γ) 155Sm reactions at 0.0536 eV energy

    NASA Astrophysics Data System (ADS)

    Uddin, M. S.; Chowdhury, M. H.; Hossain, S. M.; Latif, Sk. A.; Islam, M. A.; Hafiz, M. A.; Mubin, S. H.; Zakaria, A. K. M.; Yunus, S. M.; Azharul Islam, S. M.

    2008-11-01

    The neutron capture cross sections for the 152Sm(n,γ) 153Sm and 154Sm(n,γ) 155Sm reactions at 0.0536 eV neutron energy were measured using an activation technique based on the TRIGA Mark-II research reactor, relative to the reference reaction 197Au(n,γ) 198Au. The activity was measured nondestructively using gamma-ray spectroscopy. Our measured values at this neutron energy are the first ones and are compared with 1/ v based evaluated cross sections reported in the ENDF/B-VII and JENDL-3.3 libraries. The measured value for the 152Sm(n,γ) 153Sm reaction is 0.28% lower than JENDL-3.3 and 0.48% higher than ENDF/B-VII. Our value for the production of 155Sm is about 3% and 2.3% higher than the evaluated value with ENDF/B-VII and JENDL-3.3 at 0.0536 eV, respectively.

  20. The radar cross section of dielectric disks

    NASA Technical Reports Server (NTRS)

    Levine, D. M.

    1982-01-01

    A solution is presented for the backscatter (nonstatic) radar cross section of dielectric disks of arbitrary shape, thickness and dielectric constant. The result is obtained by employing a Kirchhoff type approximation to obtain the fields inside the disk. The internal fields induce polarization and conduction currents from which the scattered fields and the radar cross section can be computed. The solution for the radar cross section obtained in this manner is shown to agree with known results in the special cases of normal incidence, thin disks and perfect conductivity. The solution can also be written as a product of the reflection coefficient of an identically oriented slab times the physical optics solution for the backscatter cross section of a perfectly conducting disk of the same shape. This result follows directly from the Kirchhoff type approximation without additional assumptions.

  1. Absorption cross section of canonical acoustic holes

    SciTech Connect

    Crispino, Luis C. B.; Oliveira, Ednilton S.; Matsas, George E. A.

    2007-11-15

    We compute numerically the absorption cross section of a canonical acoustic hole for sound waves with arbitrary frequencies. Our outputs are in full agreement with the expected low- and high-frequency limits.

  2. Bibliography of photoabsorption cross-section data

    NASA Technical Reports Server (NTRS)

    Hudson, R. D.; Kieffer, L. J.

    1970-01-01

    This bibliography contains only references which report a measured or calculated photoabsorption cross section (relative or normalized) in regions of continuous absorption. The bibliography is current as of January 1, 1970.

  3. Cross sections of the O{sup +}+H{sub 2}{yields}OH{sup +}+H ion-molecule reaction and isotopic variants (D{sub 2}, HD): Quasiclassical trajectory study and comparison with experiments

    SciTech Connect

    Martinez, Rodrigo; Sierra, Jose Daniel; Gonzalez, Miguel

    2005-11-01

    A dynamics study [cross section and microscopic mechanism versus collision energy (E{sub T})] of the reaction O{sup +}+H{sub 2}{yields}OH{sup +}+H, which plays an important role in Earth's ionosphere and interstellar chemistry, was conducted using the quasiclassical trajectory method, employing an analytical potential energy surface (PES) recently derived by our group [R. Martinez et al., J. Chem. Phys. 120, 4705 (2004)]. Experimental excitation functions for the title reaction, as well as its isotopic variants with D{sub 2} and HD, were near-quantitatively reproduced in the calculations in the very broad collision energy range explored (E{sub T}=0.01-6.0 eV). Intramolecular and intermolecular isotopic effects were also examined, yielding data in good agreement with experimental results. The reaction occurs via two microscopic mechanisms (direct and nondirect abstraction). The results were satisfactorily interpreted based on the reaction probability and the maximum impact parameter dependences with E{sub T}, and considering the influence of the collinear [OHH]{sup +} absolute minimum of the PES on the evolution from reactants to products. The agreement between theory and experiment suggests that the reaction mainly occurs through the lowest energy PES and nonadiabatic processes are not very important in the wide collision energy range analyzed. Hence, the PES used to describe this reaction is suitable for both kinetics and dynamics studies.

  4. Effects of in-medium cross sections and optical potential on thermal-source formation in p+{sup 197}Au reactions at 6.2-14.6 GeV/c

    SciTech Connect

    Turbide, S.; Beaulieu, L.; Roy, R.; Danielewicz, P.; Huang, R.; Lynch, W.G.; Tsang, M.B.; Xi, H.; Viola, V.E.; Kwiatkowski, K.; Hsi, W.-C.; Wang, G.; Lefort, T.; Bracken, D.S.; Cornell, E.; Ginger, D.S.; Breuer, H.; Gimeno-Nogues, F.; Ramakrishnan, E.; Rowland, D.

    2004-07-01

    Effects of in-medium cross sections and of optical potential on preequilibrium emission and on formation of a thermal source are investigated by comparing the results of transport simulations with experimental results from the p+{sup 197}Au reaction at 6.2-14.6 GeV/c. The employed transport model includes light-composite-particle production and allows for inclusion of in-medium particle-particle cross-section reduction and of momentum dependence in the particle optical potentials. Compared to the past, the model incorporates improved parametrizations of elementary high-energy processes. The simulations indicate that the majority of energy deposition occurs during the first 25 fm/c of a reaction. This is followed by a preequilibrium emission and readjustment of system density and momentum distribution toward an equilibrated system. Within different variants of calculations, the best agreement with data, on the d/p and t/p yield ratios and on the residue mass and charge numbers, is obtained at the time of about 65 fm/c from the start of a reaction, for simulations employing reduced in-medium cross sections and momentum-dependent optical potentials. By that time, the preequilibrium nucleon and cluster emission, as well as mean field readjustments, drive the system to a state of depleted average density, {rho}/{rho}{sub 0}{approx}1/4-1/3 for central collisions, and low-to-moderate excitation, i.e., the region of nuclear liquid-gas phase transition.

  5. Shuttle orbiter radar cross-sectional analysis

    NASA Technical Reports Server (NTRS)

    Cooper, D. W.; James, R.

    1979-01-01

    Theoretical and model simulation studies on signal to noise levels and shuttle radar cross section are described. Pre-mission system calibrations, system configuration, and postmission system calibration of the tracking radars are described. Conversion of target range, azimuth, and elevation into radar centered east north vertical position coordinates are evaluated. The location of the impinging rf energy with respect to the target vehicles body axis triad is calculated. Cross section correlation between the two radars is presented.

  6. Ultraviolet absorption cross sections of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Lin, C. L.; Rohatgi, N. K.; Demore, W. B.

    1978-01-01

    Absorption cross-sections of hydrogen peroxide vapor and of neutral aqueous solutions of hydrogen peroxide were measured in the wavelength range from 195 to 350 nm at 296 K. The spectrophotometric procedure is described, and the reported cross-sections are compared with values obtained by other researchers. Photodissociation coefficients of atmospheric H2O2 were calculated for direct absorption of unscattered solar radiation, and the vertical distributions of these coefficients are shown for various solar zenith angles.

  7. Path forward for dosimetry cross sections

    SciTech Connect

    Griffin, P.J.; Peters, C.D.

    2011-07-01

    In the 1980's the dosimetry community embraced the need for a high fidelity quantification of uncertainty in nuclear data used for dosimetry applications. This led to the adoption of energy-dependent covariance matrices as the accepted manner of quantifying the uncertainty data. The trend for the dosimetry community to require high fidelity treatment of uncertainty estimates has continued to the current time where requirements on nuclear data are codified in standards such as ASTM E 1018. This paper surveys the current state of the dosimetry cross sections and investigates the quality of the current dosimetry cross section evaluations by examining calculated-to-experimental ratios in neutron benchmark fields. In recent years more nuclear-related technical areas are placing an emphasis on uncertainty quantification. With the availability of model-based cross sections and covariance matrices produced by nuclear data codes, some nuclear-related communities are considering the role these covariance matrices should play. While funding within the dosimetry community for cross section evaluations has been very meager, other areas, such as the solar-related astrophysics community and the US Nuclear Criticality Safety Program, have been supporting research in the area of neutron cross sections. The Cross Section Evaluation Working Group (CSEWG) is responsible for the creation and maintenance of the ENDF/B library which has been the mainstay for the reactor dosimetry community. Given the new trends in cross section evaluations, this paper explores the path forward for the US nuclear reactor dosimetry community and its use of the ENDF/B cross-sections. The major concern is maintenance of the sufficiency and accuracy of the uncertainty estimate when used for dosimetry applications. The two major areas of deficiency in the proposed ENDF/B approach are: 1) the use of unrelated covariance matrices in ENDF/B evaluations and 2) the lack of 'due consideration' of experimental data

  8. Absolute cross section for recoil detection of deuterium

    NASA Astrophysics Data System (ADS)

    Besenbacher, F.; Stensgaard, I.; Vase, P.

    1986-04-01

    The D( 4He, D) 4He cross section used for recoil detection of deuterium (D) has been calibrated on an absolute scale against the cross section of the D( 3He, α)p nuclear reaction which is often used for D profiling. For 4He energies ranging from 0.8 to ~1.8 MeV. the D( 4He, D) 4He cross section varies only slightly with incident energy and recoil angle θ (for 0° ⩽ 8 ⩽ 35°) and has a value of ~ 500 mb/sr which is significantly higher than the ~ 65 mb/sr c.m.s. cross section of the D( 3He, α)p nuclear reaction. For 4He energies ranging from ~ 1.9 to ~ 2.3 MeV, the D( 4He,D) 4He cross section exhibits a fairly narrow resonance peak (fwhm ~ 70 keV), with a maximum value (for θ = 0°) of ~ 8.5 b/sr, corresponding to a 4He energy of ~ 2130 keV. The large values of the cross section in connection with the described energy dependence makes the use of forward-recoil detection of D attractive for many purposes, e.g., D Jepth profiling (with an extreme gain in sensitivity), absolute concentration or coverage measurements, and lattice-location experiments by transmission channeling.

  9. Krypton charge exchange cross sections for Hall effect thruster models

    SciTech Connect

    Hause, Michael L.; Prince, Benjamin D.; Bemish, Raymond J.

    2013-04-28

    Following discharge from a Hall effect thruster, charge exchange occurs between ions and un-ionized propellant atoms. The low-energy cations produced can disturb operation of onboard instrumentation or the thruster itself. Charge-exchange cross sections for both singly and doubly charged propellant atoms are required to model these interactions. While xenon is the most common propellant currently used in Hall effect thrusters, other propellants are being considered, in particular, krypton. We present here guided-ion beam measurements and comparisons to semiclassical calculations for Kr{sup +} + Kr and Kr{sup 2+} + Kr cross sections. The measurements of symmetric Kr{sup +} + Kr charge exchange are in good agreement with both the calculations including spin-orbit effects and previous measurements. For the symmetric Kr{sup 2+} + Kr reaction, we present cross section measurements for center-of-mass energies between 1 eV and 300 eV, which spans energies not previously examined experimentally. These cross section measurements compare well with a simple one-electron transfer model. Finally, cross sections for the asymmetric Kr{sup 2+} + Kr {yields} Kr{sup +} + Kr{sup +} reaction show an onset near 12 eV, reaching cross sections near constant value of 1.6 A{sup 2} with an exception near 70-80 eV.

  10. Predicting the Total Charm Cross Section

    SciTech Connect

    Vogt, R

    2008-05-29

    We discuss the energy dependence of the total charm cross section and some of its theoretical uncertainties including the quark mass, scale choice and the parton densities. Extracting the total charm cross section from data is a non-trivial task. To go from a finite number of measured D mesons in a particular decay channel to the total c{bar c} cross section one must: divide by the branching ratio for that channel; correct for the luminosity, {sigma}{sub D} = N{sub D}/Lt; extrapolate to full phase space from the finite detector acceptance; divide by two to get the pair cross section from the single Ds; and multiply by a correction factor to account for unmeasured charm hadrons. Early fixed-target data were at rather low p{sub T}, making the charm quark mass the most relevant scale. At proton and ion colliders, although the RHIC experiments can access the full pT range and thus the total cross section, the data reach rather high p{sub T}, p{sub T} >> m, making p{sub T} (m{sub T}) the most relevant scale. Here we focus on the total cross section calculation where the quark mass is the only relevant scale.

  11. QuickSite Cross Section Processing

    Energy Science and Technology Software Center (ESTSC)

    2003-05-27

    This AGEM-developed system produces cross sections by inputting data in both standard and custom file formats and outputting a graphic file that can be printed or further modified in a commercial graphic program. The system has evolved over several years in order to combine and visualize a changing set of field data more rapidly than was possible with commercially available cross section software packages. It uses some commercial packages to produce the input and tomore » modify the output files. Flexibility is provided by a dynamic set of programs that are customized to accept varying input and accomodate varying output requirements. There are two basic types of routines: conversion routines and cross section generation routines. The conversion routines convery various data files to logger file format which is compatible with a standard file format for LogPlot 98, a commonly used commercial log plotting program. The cross section routines generate cross sections and apply topography to these cross sections. All of the generation routines produce a standard graphic DXF file, which is the format used in AutoCAD and can then be modified in a number of available graphics programs.« less

  12. Towards Reliable Cross Sections for National Security Applications

    SciTech Connect

    Escher, J E; Dietrich, F S; Nobre, G A; Thompson, I J

    2011-02-24

    Stockpile stewardship requires the description of weapons performance without resorting to underground nuclear testing. In the earlier tests, selected isotopes were used as detectors, and recovered after irradiation. Aspects of nuclear device performance were inferred by comparing the measured isotopic ratios to those predicted from simulations. The reaction flows that produce the final isotopic distributions proceed through regions of the nuclear chart that include unstable nuclei. Presently, improved nuclear data input is required to reanalyze prior tests and to certify the stockpile's reliability and safety. Many important cross sections are unknown, as is shown in the example of the Yttrium reaction network (Figure 1). The relevant reactions include (n,2n), (n,n'), (n,gamma), (n,p) and other charged-particle emitting reactions. The cross sections have to be calculated or inferred from indirect measurements. In both cases, reliable optical models that are valid a few nucleons away from stability are needed. The UNEDF Nuclear Reaction activities address this need by combining nuclear-structure input from UNEDF structure calculations with modern reaction theory and large-scale computational capabilities to develop microscopic nucleon-nucleus optical potentials that can be extrapolated to unstable nuclei. In addition, the reaction calculation tools and optical models developed in this context are proving valuable for planning and interpreting indirect (surrogate) measurements of the required cross sections.

  13. Radiative neutron capture cross sections on 176Lu at DANCE

    NASA Astrophysics Data System (ADS)

    Roig, O.; Jandel, M.; Méot, V.; Bond, E. M.; Bredeweg, T. A.; Couture, A. J.; Haight, R. C.; Keksis, A. L.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.

    2016-03-01

    The cross section of the neutron capture reaction 176Lu(n ,γ ) has been measured for a wide incident neutron energy range with the Detector for Advanced Neutron Capture Experiments at the Los Alamos Neutron Science Center. The thermal neutron capture cross section was determined to be (1912 ±132 ) b for one of the Lu natural isotopes, 176Lu. The resonance part was measured and compared to the Mughabghab's atlas using the R -matrix code, sammy. At higher neutron energies the measured cross sections are compared to ENDF/B-VII.1, JEFF-3.2, and BRC evaluated nuclear data. The Maxwellian averaged cross sections in a stellar plasma for thermal energies between 5 keV and 100 keV were extracted using these data.

  14. Determination of the {sup 233}Pa(n,f) reaction cross section from 11.5 to 16.5 MeV neutron energy by the hybrid surrogate ratio approach

    SciTech Connect

    Nayak, B. K.; Saxena, A.; Biswas, D. C.; Mirgule, E. T.; John, B. V.; Santra, S.; Vind, R. P.; Choudhury, R. K.; Ganesan, S.

    2008-12-15

    A new hybrid surrogate ratio approach has been employed to determine neutron-induced fission cross sections of {sup 233}Pa in the energy range of 11.5 to 16.5 MeV for the first time. The fission probability of {sup 234}Pa and {sup 236}U compound nuclei produced in {sup 232}Th({sup 6}Li, {alpha}){sup 234}Pa and {sup 232}Th({sup 6}Li, d){sup 236}U transfer reaction channels has been measured at E{sub lab}=38.0 MeV in the excitation energy range of 17.0 to 22.0 MeV within the framework of the absolute surrogate method. The {sup 233}Pa(n,f) cross sections are then deduced from the measured fission decay probability ratios of {sup 234}Pa and {sup 236}U compound nuclei using the surrogate ratio method. The {sup 233}Pa(n,f) cross section data from the present experiment along with the data from the literature, covering the neutron energy range of 1.0 to 16.5 MeV have been compared with the predictions of statistical model code EMPIRE-2.19. While the present data are consistent with the model predictions, there is a discrepancy between the earlier experimental data and EMPIRE-2.19 predictions in the neutron energy range of 7.0 to 10.0 MeV.

  15. Cross sections and tensor analyzing powers A{sub yy} of the reaction {sup 1}H(d-vector, pp)n in 'symmetric constant relative energy' geometries at E{sub d}=19 MeV

    SciTech Connect

    Ley, J.; Dueweke, C.; Emmerich, R.; Imig, A.; Paetz gen Schieck, H.; Golak, J.; Witala, H.; Epelbaum, E.; Deltuva, A.; Fonseca, A.C.; Gloeckle, W.; Meissner, U.-G.; Nogga, A.; Sauer, P.U.

    2006-06-15

    We measured the cross sections and tensor analyzing powers of the {sup 1}H(d-vector,pp)n breakup reaction at E{sub d}=19 MeV in four symmetric constant relative energy (SCRE) configurations. The data are compared with theoretical predictions from four different approaches: the first based on high-precision (semi)phenomenological potentials alone or, the second, combined with model three-nucleon forces, and the third based on chiral forces up to next-to-next-to-leading order (NNLO) in the chiral expansion. In these cases the Coulomb interaction is not included. In addition, a fourth approach consists in a comparison with predictions based on CD Bonn including the {delta} excitation and the Coulomb force. In all cases the measured cross sections are significantly below the theoretical values, whereas the magnitudes of the tensor analyzing powers agree within the error bars in three of the four cases. The apparent discrepancies in the breakup cross sections are similar to the known differences for the space-star breakup. This adds to the data base of unsolved low-energy discrepancies (puzzles)

  16. Charged pion form factor between $Q^2$=0.60 and 2.45 GeV$^2$. I. Measurements of the cross section for the ${^1}$H($e,e'\\pi^+$)$n$ reaction.

    SciTech Connect

    Blok, Henk; Horn, Tanja; Huber, Garth; Beise, Elizabeth; Gaskell, David; Mack, David; Tadevosyan, Vardan; Volmer, Jochen; Abbott, David; Aniol, Konrad; Anklin, Heinz; Armstrong, Christopher; Arrington, John; Assamagan, Ketevi; Avery, Steven; Baker, O; Barrett, Robert; Bochna, Christopher; Boeglin, Werner; Brash, Edward; Breuer, Herbert; Chang, C; Chang, C C; Chant, Nicholas; Christy, Michael; Dunne, James; Eden, Thomas; Ent, Rolf; Fenker, Howard; Gibson, Edward; Gilman, Ronald; Gustafsson, Kenneth; Hinton, Wendy; Holt, Roy; Jackson, Harold; uk Jin, Seong; Jones, Mark; Keppel, Cynthia; Kim, pyunghun; Kim, Wooyoung; King, Paul; Klein, Andreas; Koltenuk, Douglas; Kovaltchouk, Vitali; Liang, Meihua; Liu, Jinghua; Lolos, George; Lung, Allison; Margaziotis, Demetrius; Markowitz, Pete; Matsumura, Akihiko; McKee, David; Meekins, David; Mitchell, Joseph; Miyoshi, Toshinobu; Mkrtchyan, Hamlet; Mueller, Robert; Niculescu, Gabriel; Niculescu, Maria-Ioana; Okayasu, Yuichi; Pentchev, Lubomir; Perdrisat, Charles; Pitz, David; Potterveld, David; Punjabi, Vina; Qin, Liming; Reimer, Paul; Reinhold, Joerg; Roche, Julie; Roos, Philip; Sarty, Adam; Shin, Ilkyoung; Smith, Gregory; Stepanyan, Stepan; Tang, Liguang; Tvaskis, Vladas; van der Meer, Rob; Vansyoc, Kelley; Van Westrum, Derek; Vidakovic, Sandra; Vulcan, William; Warren, Glen; Wood, Stephen; Xu, C; Yan, Chen; Zhao, Wenxia; Zheng, Xiaochao; Zihlmann, Benedikt

    2008-10-01

    DOI: http://dx.doi.org/10.1103/PhysRevC.78.045202
    Cross sections for the reaction 1H(e,e'pi+)n were measured in Hall C at Thomas Jefferson National Accelerator Facility (JLab) using the high-intensity Continuous Electron Beam Accelerator Facility (CEBAF) to determine the charged pion form factor. Data were taken for central four-momentum transfers ranging from Q2=0.60 to 2.45 GeV2 at an invariant mass of the virtual photon-nucleon system of W=1.95 and 2.22 GeV. The measured cross sections were separated into the four structure functions sigmaL,sigmaT,sigmaLT, and sigmaTT. The various parts of the experimental setup and the analysis steps are described in detail, including the calibrations and systematic studies, which were needed to obtain high-precision results. The different types of systematic uncertainties are also discussed. The results for the separated cross sections as a function of the Mandelstam variable t at the different values of Q2 are presented. Some global featu

  17. Differential cross section measurements of 27Al(p,p/γ)27Al and 27Al(p,αγ)24Mg reactions in the energy range of 1.6-3.0 MeV

    NASA Astrophysics Data System (ADS)

    Jokar, A.; Kakuee, O.; Lamehi-Rachti, M.; Sharifzadeh, N.; Fathollahi, V.

    2015-11-01

    In this work measurement of differential cross sections of 27Al(p,p/γ)27Al (Eγ = 844, 1014 keV) and 27Al(p,αγ)24Mg (Eγ = 1369 keV) nuclear reactions in the proton energy range of 1.6-3.0 MeV are described and the measured values are presented. Thin Al target was prepared by evaporating a 26 μg/cm2 Al onto a 129 μg/cm2 self-supporting Ag film. The gamma-rays and backscattered protons were detected simultaneously. The gamma-rays and protons were collected by an HPGe detector placed at an angle of 90° with respect to beam direction and an ion implanted Si detector placed at a scattering angle of 165°, respectively. In this experimental setup the great advantage is that differential cross sections could be independent on absolute values of the collected beam charge. The overall systematic uncertainty of cross sections was estimated to be ±9% while statistical errors were less than ±5%.

  18. abo-cross: Hydrogen broadening cross-section calculator

    NASA Astrophysics Data System (ADS)

    Barklem, P. S.; Anstee, S. D.; O'Mara, B. J.

    2015-07-01

    Line broadening cross sections for the broadening of spectral lines by collisions with neutral hydrogen atoms have been tabulated by Anstee & O'Mara (1995), Barklem & O'Mara (1997) and Barklem, O'Mara & Ross (1998) for s-p, p-s, p-d, d-p, d-f and f-d transitions. abo-cross, written in Fortran, interpolates in these tabulations to make these data more accessible to the end user. This code can be incorporated into existing spectrum synthesis programs or used it in a stand-alone mode to compute line broadening cross sections for specific transitions.

  19. Revised cross section for RHIC dipole magnets

    SciTech Connect

    Thompson, P.A.; Gupta, R.C.; Kahn, S.A.; Hahn, H.; Morgan, G.H.; Wanderer, P.J.; Willen, E.

    1991-01-01

    Using the experience gained in designing and building Relativistic Heavy Ion Collider (RHIC) dipole prototype magnets an improved cross section has been developed. Significant features of this design include the use of only three wedges for field shaping and wedge cross sections which are sectors of an annulus. To aid in the understanding of the actual magnets, one has been sectioned, and detailed mechanical and photographic measurements made of the wire positions. The comparison of these measurements with the magnetic field measurements will is presented. 2 refs, 3 figs., 2 tabs.

  20. Actinide cross section program at ORELA

    SciTech Connect

    Dabbs, J.W.T.

    1980-01-01

    The actinide cross section program at ORELA, the Oak Ridge Electron Linear Accelerator, is aimed at obtaining accurate neutron cross sections (primarily fission, capture, and total) for actinide nuclides which occur in fission reactors. Such cross sections, measured as a function of neutron energy over as wide a range of energies as feasible, comprise a data base that permits calculated predictions of the formation and removal of these nuclides in reactors. The present program is funded by the Division of Basic Energy Sciences of DOE, and has components in several divisions at ORNL. For intensively ..cap alpha..-active nuclides, many of the existing fission cross section data have been provided by underground explosions. New measurement techniques, developed at ORELA, now permit linac measurements on fissionable nuclides with alpha half-lives as short as 28 years. Capture and capture-plus-fission measurements utilize scintillation detectors (of capture ..gamma.. rays and fission neutrons) in which pulse shape discrimination plays an important role. Total cross sections can be measured at ORELA on samples of only a few milligrams. A simultaneous program of chemical and isotopic analyses of samples irradiated in EBR-II is in progress to provide benchmarks for the existing differential measurements. These analyses are being studied with updated versions of ORIGEN and with sensitivity determinations. Calculations of the sensitivity to cross section changes of various aspects of the nuclear fuel cycle are also being made. Even in this relatively mature field, many cross sections still require improvements to provide an adequate data base. Examples of recent techniques and measurements are presented. 12 figures, 3 tables.

  1. Cross section measurements via residual nuclear decays: Analysis methods

    SciTech Connect

    Zhou Fengqun; Gao Lei; Li Kuohu; Song Yueli; Zhang Fang; Kong Xiangzhong; Luo Junhua

    2009-11-15

    We develop an approach to calculating the pure cross section of the ground state of artificial radioactive nuclides that subtracts the effect of an excited state on the ground state. We apply a formalism to obtaining pure cross sections by subtracting the effect of excited states in the reactions {sup 122}Te(n,2n){sup 121}Te{sup g} and {sup 128}Te(n,2n){sup 127}Te{sup g}, induced by neutrons of about 14 MeV. The cross sections are measured by an activation relative to the {sup 93}Nb(n,2n){sup 92}Nb{sup m} reaction and are compared with results that take into account the effect of the excited state. Measurements are carried out by {gamma} detection using a coaxial high-purity germanium (HPGe) detector. As samples, spectroscopically pure Te powder is used. The fast neutrons are produced by the {sup 3}H(d,n){sup 4}He reaction. The neutron energies in these measurements are determined using the method of cross-section ratios between the {sup 90}Zr(n,2n){sup 89}Zr{sup m+g} and {sup 93}Nb(n,2n){sup 92}Nb{sup m} reactions.

  2. Cross sections for the formation of {sup 195}Hg{sup m,g}, {sup 197}Hg{sup m,g}, and {sup 196}Au{sup m,g} in {alpha} and {sup 3}He-particle induced reactions on Pt: Effect of level density parameters on the calculated isomeric cross-section ratio

    SciTech Connect

    Sudar, S.; Qaim, S.M.

    2006-03-15

    Excitation functions were measured for the reactions {sup nat}Pt({sup 3}He,xn){sup 195}Hg{sup m,g},{sup nat}Pt({sup 3}He,xn){sup 197}Hg{sup m,g},{sup nat}Pt({sup 3}He,= x){sup 196}Au{sup m,g}, and {sup nat}Pt({alpha},xn){sup 197}Hg{sup m,g} over the energy range of 18-35 MeV for {sup 3}He particles and 17-26 MeV for {alpha} particles. The reactions {sup 197}Au(p,n){sup 197}Hg{sup m,g} were also investigated over the proton energy range of 6-20 MeV. The three projectiles were produced at the Juelich variable-energy compact cyclotron (CV 28). Use was made of the activation technique in combination with conventional high-resolution as well as low-energy HPGe-detector {gamma}-ray spectroscopy. For most of the reactions, the present measurements provide the first consistent sets of data. From the available experimental data, isomeric cross-section ratios were determined for the above-mentioned reactions. Nuclear model calculations using the code STAPRE, which employs the Hauser-Feshbach (statistical model) and exciton model (precompound effects) formalisms, were undertaken to describe the formation of both the isomeric and the ground states of the products. The calculations were compared with the results of the EMPIRE-II code. The excitation functions of the ({sup 3}He,xn) and ({alpha},xn) processes are described well by the theory. In the case of ({sup 3}He,pxn) reactions, however, considerable deviations were observed between the experiment and the theory, presumably due to strong contributions from direct interactions. A description of the isomeric cross-section ratio by the model was possible only with a very low value of {eta}, i.e., the {theta}{sub eff}/{theta}{sub rig} ratio. A mass dependence of {eta} is proposed.

  3. Undergraduate Measurements of Neutron Cross Sections

    NASA Astrophysics Data System (ADS)

    Hicks, S. F.; Vanhoy, J. R.; French, A. J.; Santonil, Z. C.; Crider, B. P.; Peters, E. E.; McEllistrem, M. T.; Prados-Estévez, F. M.; Ross, T. J.; Yates, S. W.

    Undergraduate students at the University of Dallas have investigated basic properties of nuclei through γ-ray and neutron spectroscopy following neutron scattering. The former has been used primarily for nuclear structure investigations, while the latter has been used to measure neutron scattering cross sections important for fission reactor applications. A series of (n,n') and (n,n'γ) measurements have been made on 54Fe and 56Fe to determine neutron cross sections for scattering to excited levels in these nuclei. The former provides the cross sections directly and the latter are used to deduce inelastic neutron scattering cross sections by measuring the γ-ray production cross sections to states not easily resolved in neutron spectroscopy. All measurements have been completed at the University of Kentucky Accelerator Laboratory using a 7-MV Model CN Van de Graaff accelerator, along with the neutron production and neutron and γ-ray detection systems located there. Students participate in accelerator operation, experimental setup, data acquisition, and data analyses. An overview of the research program and student contributions is presented.

  4. Modeling the heavy ion upset cross section

    NASA Astrophysics Data System (ADS)

    Connell, L. W.; McDaniel, P. J.; Prinja, A. K.; Sexton, F. W.

    1995-04-01

    The standard Rectangular Parallelepiped (RPP) construct is used to derive a closed form expression for, sigma-bar (theta, phi, L) the directional-spectral heavy ion upset cross section. This is an expected value model obtained by integrating the point-value cross section model, sigma (theta, phi, L, E), also developed here, with the Weibull density function, f(E), assumed to govern the stochastic behavior of the upset threshold energy, E. A comparison of sigma-bar (theta, phi, L) with experimental data show good agreement, lending strong credibility to the hypothesis that E-randomness is responsible for the shape of the upset cross section curve. The expected value model is used as the basis for a new, rigorous mathematical formulation of the effective cross section concept. The generalized formulation unifies previous corrections to the inverse cosine scaling, collapsing to Petersen's correction, (cos theta - (h/l) sin theta)(sup -1), near threshold and Sexton's, (cos theta + (h/l) sin theta)(sup -1), near saturation. The expected value cross section model therefore has useful applications in both upset rate prediction and test data analysis.

  5. Cross reaction of anti-human CD monoclonal antibodies on guinea pig cells: A summary of the guinea pig section of the HLDA8 Animal Homologues data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A panel of 377 commercially available monoclonal antibodies (mAbs) specific for a total of 144 CD antigens was submitted to the 8th International Workshop on Human Leukocyte Differentiation Antigens (HLDA8, Adelaide, Australia) for cross-reactivity studies in a range of vertebrate species. Each of ...

  6. Algorithmic analysis of quantum radar cross sections

    NASA Astrophysics Data System (ADS)

    Lanzagorta, Marco; Venegas-Andraca, Salvador

    2015-05-01

    Sidelobe structures on classical radar cross section graphs are a consequence of discontinuities in the surface currents. In contrast, quantum radar theory states that sidelobe structures on quantum radar cross section graphs are due to quantum interference. Moreover, it is conjectured that quantum sidelobe structures may be used to detect targets oriented off the specular direction. Because of the high data bandwidth expected from quantum radar, it may be necessary to use sophisticated quantum signal analysis algorithms to determine the presence of stealth targets through the sidelobe structures. In this paper we introduce three potential quantum algorithmic techniques to compute classical and quantum radar cross sections. It is our purpose to develop a computer science-oriented tool for further physical analysis of quantum radar models as well as applications of quantum radar technology in various fields.

  7. The cross section for double Compton scattering

    NASA Technical Reports Server (NTRS)

    Gould, R. J.

    1984-01-01

    Employing elementary methods in nonrelativistic quantum electrodynamics, the cross section for gamma sub 0 + e yields e + gamma + gamma is computed for arbitrary energy in the spectrum of the outgoing photons. The final result is given, differential in the energy of one of these photons, for the case where the incident photon is unpolarized and has energy E sub 0 much less than mc-squared, a polarization sum and angular integration being performed for the final-state photons. The cross section has a simple algebraic form resulting from contributions from the sum of squared direct and exchange amplitudes; interference terms from these amplitudes do not contribute to the angular-integrated cross section.

  8. Top differential cross section measurements (Tevatron)

    SciTech Connect

    Jung, Andreas W.

    2012-01-01

    Differential cross sections in the top quark sector measured at the Fermilab Tevatron collider are presented. CDF used 2.7 fb{sup -1} of data and measured the differential cross section as a function of the invariant mass of the t{bar t} system. The measurement shows good agreement with the standard model and furthermore is used to derive limits on the ratio {kappa}/M{sub Pl} for gravitons which decay to top quarks in the Randall-Sundrum model. D0 used 1.0 fb{sup -1} of data to measure the differential cross section as a function of the transverse momentum of the top-quark. The measurement shows a good agreement to the next-to-leading order perturbative QCD prediction and various other standard model predictions.

  9. New Parameterization of Neutron Absorption Cross Sections

    NASA Technical Reports Server (NTRS)

    Tripathi, Ram K.; Wilson, John W.; Cucinotta, Francis A.

    1997-01-01

    Recent parameterization of absorption cross sections for any system of charged ion collisions, including proton-nucleus collisions, is extended for neutron-nucleus collisions valid from approx. 1 MeV to a few GeV, thus providing a comprehensive picture of absorption cross sections for any system of collision pairs (charged or uncharged). The parameters are associated with the physics of the problem. At lower energies, optical potential at the surface is important, and the Pauli operator plays an increasingly important role at intermediate energies. The agreement between the calculated and experimental data is better than earlier published results.

  10. Precise neutron inelastic cross section measurements

    SciTech Connect

    Negret, Alexandru

    2012-11-20

    The design of a new generation of nuclear reactors requires the development of a very precise neutron cross section database. Ongoing experiments performed at dedicated facilities aim to the measurement of such cross sections with an unprecedented uncertainty of the order of 5% or even smaller. We give an overview of such a facility: the Gamma Array for Inelastic Neutron Scattering (GAINS) installed at the GELINA neutron source of IRMM, Belgium. Some of the most challenging difficulties of the experimental approach are emphasized and recent results are shown.

  11. Neutron capture cross section of 136 Xe

    NASA Astrophysics Data System (ADS)

    Daugherty, Sean; Albert, Joshua; Johnson, Tessa; O'Conner, Thomasina; Kaufman, Lisa

    2015-04-01

    136 Xe is an important 0 νββ candidate, studied in experiments such as EXO-200 and, in the future, nEXO. These experiments require a precise study of neutron capture for their background models. The neutron capture cross section of 136 Xe has been measured at the Detector for Advanced Capture Experiments (DANCE) at the Los Alamos Neutron Science Center. A neutron beam ranging from thermal energy to 100 keV was incident on a gas cell filled with isotopically pure 136 Xe . We will discuss the measurement of partial neutron capture cross sections at thermal and first neutron resonance energies along with corresponding capture gamma cascades.

  12. Neutron Capture Cross Section of 239Pu

    NASA Astrophysics Data System (ADS)

    Mosby, S.; Arnold, C.; Bredeweg, T. A.; Couture, A.; Jandel, M.; O'Donnell, J. M.; Rusev, G.; Ullmann, J. L.; Chyzh, A.; Henderson, R.; Kwan, E.; Wu, C. Y.

    2014-09-01

    The 239Pu(n,γ) cross section has been measured over the energy range 10 eV - 10 keV using the Detector for Advanced Neutron Capture Experiments (DANCE) as part of a campaign to produce precision (n,γ) measurements on 239Pu in the keV region. Fission coincidences were measured with a PPAC and used to characterize the prompt fission γ-ray spectrum in this region. The resulting spectra will be used to better characterize the fission component of another experiment with a thicker target to extend the (n,γ) cross section measurement well into the keV region.

  13. Optical Model and Cross Section Uncertainties

    SciTech Connect

    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.

  14. Infrared absorption cross sections of alternative CFCs

    NASA Technical Reports Server (NTRS)

    Clerbaux, Cathy; Colin, Reginald; Simon, Paul C.

    1994-01-01

    Absorption cross sections have obtained in the infrared atmospheric window, between 600 and 1500 cm(exp -1), for 10 alternative hydrohalocarbons: HCFC-22, HCFC-123, HCFC-124, HCFC-141b, HCFC-142b, HCFC-225ca, HCFC-225cb, HFC-125, HFC-134a, and HFC-152a. The measurements were made at three temperatures (287K, 270K and 253K) with a Fourier transform spectrometer operating at 0.03 cm(exp -1) apodized resolution. Integrated cross sections are also derived for use in radiative models to calculate the global warming potentials.

  15. Determination of the cross section for (n,p) reaction with producing short-lived nuclei on the 162,163Dy isotopes at 13.5 and 14.8 MeV

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    Activation cross-sections for the 162Dy(n,p)162Tb and 163Dy(n,p)163Tb reactions have been measured by means of the activation technique and a coaxial HPGe γ-ray detector at 13.5 and 14.8 MeV. The fast neutrons were produced via the 3H(d,n)4He reaction on Pd-300 neutron generator. The natural high-purity Dy2O3 powder was used as target material. Theoretical excitation functions were calculated using the nuclear-reaction codes EMPIRE-3.2 Malta and TALYS-1.6 with default parameters, at neutron energies varying from the reaction threshold to 20 MeV. The results were also discussed and compared with some corresponding values found in the literature, with the comprehensive evaluation data in ENDF/B-VII.1 and JENDF-4.0 libraries, and with the estimates obtained from a published empirical formula based on the statistical model with Q-value dependence and odd-even effects taken into consideration.

  16. Measurement of the 242Pu neutron capture cross section

    NASA Astrophysics Data System (ADS)

    Buckner, M. Q.; Wu, C. Y.; Henderson, R. A.; Bucher, B.; Bredeweg, T. A.; Baramsai, B.; Couture, A.; Jandel, M.; Mosby, S.; O'Donnell, J. M.; Ullmann, J. L.; Chyzh, A.; Dance Collaboration

    2015-10-01

    Precision (n,f) and (n, γ) cross sections are important for the network calculations of the radiochemical diagnostic chain for the U.S. DOE's Stockpile Stewardship Program. 242Pu(n, γ) cross section is relevant to the network calculations of Pu and Am. Additionally, new reactor concepts have catalyzed considerable interest in the measurement of improved cross sections for neutron-induced reactions on key actinides. To date, little or no experimental data has been reported on 242Pu(n, γ) for incident neutron energy below 50 keV. A new measurement of the 242Pu(n, γ) reaction was performed with the DANCE together with an improved PPAC for fission-fragment detection at LANSCE during FY14. The relative scale of the 242Pu(n, γ) cross section spans four orders of magnitude for incident neutron energies from thermal to ~ 30 keV. The absolute scale of the 242Pu(n, γ) cross section is set according to the measured 239Pu(n,f) resonance at 7.8 eV; the target was spiked with 239Pu for this measurement. The absolute 242Pu(n, γ) neutron capture cross section is ~ 30% higher than the cross section reported in ENDF for the 2.7 eV resonance. Latest results to be reported. Funded by U.S. DOE Contract No. DE-AC52-07NA27344 (LLNL) and DE-AC52-06NA25396 (LANL). U.S. DOE/NNSA Office of Defense Nuclear Nonproliferation Research and Development. Isotopes (ORNL).

  17. Direct total cross section measurement of the 16O(α,γ)20Ne reaction at Ec.m.=2.26 MeV

    NASA Astrophysics Data System (ADS)

    Hager, U.; Brown, J. R.; Buchmann, L.; Carmona-Gallardo, M.; Erikson, L.; Fallis, J.; Greife, U.; Hutcheon, D.; Ottewell, D.; Ruiz, C.; Sjue, S.; Vockenhuber, C.

    2011-08-01

    In stellar helium burning, 16O represents the endpoint of the helium-burning sequence due to the low rate of 16O(α,γ)20Ne. We present a new direct measurement of the total capture reaction rate of 16O(α,γ)20Ne at Ec.m.=2.26MeV employing the DRAGON recoil separator. For the first time, the total S factor and its contributing direct capture transitions could be determined in one experiment.

  18. Gynecological Manifestations, Histopathological Findings, and Schistosoma-Specific Polymerase Chain Reaction Results Among Women With Schistosoma haematobium Infection: A Cross-sectional Study in Madagascar

    PubMed Central

    Randrianasolo, Bodo Sahondra; Jourdan, Peter Mark; Ravoniarimbinina, Pascaline; Ramarokoto, Charles Emile; Rakotomanana, Fanjasoa; Ravaoalimalala, Vololomboahangy Elisabeth; Gundersen, Svein Gunnar; Feldmeier, Hermann; Vennervald, Birgitte Jyding; van Lieshout, Lisette; Roald, Borghild; Leutscher, Peter; Kjetland, Eyrun Floerecke

    2015-01-01

    Background. The pathophysiology of female genital schistosomiasis (FGS) is only partially understood. This study aims to describe the histopathological findings, polymerase chain reaction (PCR) results, and gynecological manifestations of FGS in women with different intensities of Schistosoma haematobium infection. Methods. Women aged 15–35 years living in an S. haematobium-endemic area in Madagascar underwent pelvic and colposcopic examinations. Small biopsy specimens were obtained from lesions and examined histopathologically. Schistosoma PCR was done on urine, biopsy, cervicovaginal lavage, and genital mucosal surface specimens. Results. Sandy patches and rubbery papules were found in 41 of 118 women (35%). Rubbery papules reflected an intense cellular immune reaction dominated by eosinophils, epithelial erosion, and viable ova. There was a significant decrease in the prevalence of rubbery papules with age, even after adjustment for urinary ova excretion. The sandy patches with grains showed moderate cellular immune reaction and ova (viable and/or calcified). They were most prevalent in cases with low-intensity urinary S. haematobium infection. Forty-two percent of women with Schistosoma-negative urine specimens had at least 1 genital specimen test positive for Schistosoma by PCR. Conclusions. The results indicate a diversity of lesions caused by S. haematobium and a dynamic evolution of the genital lesions. Schistosoma PCR may give an indication of the diagnosis. PMID:25725656

  19. Elastic breakup cross sections of well-bound nucleons

    NASA Astrophysics Data System (ADS)

    Wimmer, K.; Bazin, D.; Gade, A.; Tostevin, J. A.; Baugher, T.; Chajecki, Z.; Coupland, D.; Famiano, M. A.; Ghosh, T. K.; Grinyer, G. F.; Howard, M. E.; Kilburn, M.; Lynch, W. G.; Manning, B.; Meierbachtol, K.; Quarterman, P.; Ratkiewicz, A.; Sanetullaev, A.; Showalter, R. H.; Stroberg, S. R.; Tsang, M. B.; Weisshaar, D.; Winkelbauer, J.; Winkler, R.; Youngs, M.

    2014-12-01

    The 9Be(28Mg,27Na ) one-proton removal reaction with a large proton separation energy of Sp(28Mg ) =16.79 MeV is studied at intermediate beam energy. Coincidences of the bound 27Na residues with protons and other light charged particles are measured. These data are analyzed to determine the percentage contributions to the proton removal cross section from the elastic and inelastic nucleon removal mechanisms. These deduced contributions are compared with the eikonal reaction model predictions and with the previously measured data for reactions involving the removal of more weakly bound protons from lighter nuclei. The role of transitions of the proton between different bound single-particle configurations upon the elastic breakup cross section is also quantified in this well-bound case. The measured and calculated elastic breakup fractions are found to be in good agreement.

  20. Cross sections of the (n ,p ) reaction on the 78Se and 80Se isotopes measured for 13.73 MeV to 14.77 MeV and estimated for 10 MeV to 20 MeV neutron energies

    NASA Astrophysics Data System (ADS)

    Attar, F. M. D.; Dhole, S. D.; Bhoraskar, V. N.

    2014-12-01

    The cross sections of 78Se(n ,p ) 78As and 80Se(n ,p ) 80As reactions were measured at five neutron energies over the range 13.73 MeV to 14.77 MeV using 56Fe and 19F as monitor elements, respectively. The cross sections were also theoretically estimated using EMPIRE-II and TALYS codes over 10 MeV to 20 MeV neutrons and matched with the experimental cross sections by making proper choice of the model parameters. The theoretical and experimental cross sections of 80Se(n ,p ) 80As reaction are smaller as compared to the 78Se(n ,p ) 78As reaction at each neutron energy. This difference is attributed to the competing 80Se(n ,2 n )79Se and 80Se( n ,α )Ge77m reactions, which effectively decrease the cross sections of 80Se(n ,p ) 80As reaction as compared to that of the 78Se(n ,p ) 78As reaction over the neutron energy range used in the present work. The cross sections of 78Se(n ,p ) 78As and 80Se(n ,p ) 80As reactions estimated by the EMPIRE-II code initially increase but later on decrease with neutron energy, respectively, above 16 MeV and 19 MeV, whereas those estimated by the TALYS code continuously increase with neutron energy. The present results indicate that the trends in the variation of cross section with neutron energy depend on the model used in the calculations. The cross sections of the 80Se(n ,p ) 80As reaction at different neutron energies reported in the present work can be added as a new data in the nuclear data library.

  1. MINING INTEGRAL ACTINIDES CROSS SECTIONS FROM REACTOR DATA

    SciTech Connect

    PUIGH RJ

    2009-09-11

    The conclusions of this paper are: (1) mining of actinide cross-sections from reactor data is a viable and inexpensive approach to confirm burn-up codes; (2) extensive data for actinides in Hanford test data ({approx} 200 radiochemical analyses); (3) not only cross-section values and reaction rates can be established but also possible benchmark like data can be constructed to test and validate reactor and criticality safety codes such as SCALE/KENO or MCNPX; and (4) analysis along multiple transmutation paths can be evaluated to show consistency.

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

    SciTech Connect

    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: /sup 55/Mn(n,..gamma..), /sup 59/Co(n,..gamma..) and /sup 197/Au(n,..gamma..). 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. Comprehensive Nuclear Model Code, Nucleons, Ions, Induced Cross-Sections

    Energy Science and Technology Software Center (ESTSC)

    2002-09-27

    EMPIRE-II is a flexible code for calculation of nuclear reactions in the frame of combined op0tical, Multistep Direct (TUL), Multistep Compound (NVWY) and statistical (Hauser-Feshbach) models. Incident particle can be a nucleon or any nucleus (Heavy Ion). Isomer ratios, residue production cross sections and emission spectra for neutrons, protons, alpha- particles, gamma-rays, and one type of Light Ion can be calculated. The energy range starts just above the resonance region for neutron induced reactions andmore » extends up to several hundreds of MeV for the Heavy Ion induced reactions.« less

  4. Comprehensive Nuclear Model Code, Nucleons, Ions, Induced Cross-Sections

    SciTech Connect

    2002-09-27

    EMPIRE-II is a flexible code for calculation of nuclear reactions in the frame of combined op0tical, Multistep Direct (TUL), Multistep Compound (NVWY) and statistical (Hauser-Feshbach) models. Incident particle can be a nucleon or any nucleus (Heavy Ion). Isomer ratios, residue production cross sections and emission spectra for neutrons, protons, alpha- particles, gamma-rays, and one type of Light Ion can be calculated. The energy range starts just above the resonance region for neutron induced reactions and extends up to several hundreds of MeV for the Heavy Ion induced reactions.

  5. Direct Total Cross Section Measurement of the 16O(α,γ)20Ne Reaction at Ec.m. = 2.26 MeV

    SciTech Connect

    Hager, Ulrike; Brown, James R.; Buchmann, Lothar R.; Carmona-Gallardo, Mariano; Erikson, Luke E.; Fallis, Jennifer S.; Greife, Uwe; Hutcheon, Dave; Ottewell, Dave; Ruiz, Chris; Sjue, Sky; Vockenhuber, Cristof

    2011-08-23

    In stellar helium burning, (16)O represents the endpoint of the helium-burning sequence due to the low rate of (16)O(alpha,gamma)(20)Ne. We present a new direct measurement of the total capture reaction rate of (16)O(alpha,gamma)(20)Ne at E(c.m.) = 2.26MeV employing the DRAGON recoil separator. For the first time, the total S factor and its contributing direct capture transitions could be determined in one experiment.

  6. Testing (Validating?) Cross Sections with ICSBEP Benchmarks

    SciTech Connect

    Kahler, Albert C. III

    2012-06-28

    We discuss how to use critical benchmarks from the International Handbook of Evaluated Criticality Safety Benchmark Experiments to determine the applicability of specific cross sections to the end-user's problem of interest. Particular attention is paid to making sure the selected suite of benchmarks includes the user's range of applicability (ROA).

  7. Cross-sectional structural parameters from densitometry

    NASA Technical Reports Server (NTRS)

    Cleek, Tammy M.; Whalen, Robert T.

    2002-01-01

    Bone densitometry has previously been used to obtain cross-sectional properties of bone from a single X-ray projection across the bone width. Using three unique projections, we have extended the method to obtain the principal area moments of inertia and orientations of the principal axes at each scan cross-section along the length of the scan. Various aluminum phantoms were used to examine scanner characteristics to develop the highest accuracy possible for in vitro non-invasive analysis of cross-sectional properties. Factors considered included X-ray photon energy, initial scan orientation, the angle spanned by the three scans (included angle), and I(min)/I(max) ratios. Principal moments of inertia were accurate to within +/-3.1% and principal angles were within +/-1 degrees of the expected value for phantoms scanned with included angles of 60 degrees and 90 degrees at the higher X-ray photon energy (140 kVp). Low standard deviations in the error (0.68-1.84%) also indicate high precision of calculated measurements with these included angles. Accuracy and precision decreased slightly when the included angle was reduced to 30 degrees. The method was then successfully applied to a pair of excised cadaveric tibiae. The accuracy and insensitivity of the algorithms to cross-sectional shape and changing isotropy (I(min)/I(max)) values when various included angles are used make this technique viable for future in vivo studies.

  8. Cross sections relevant to gamma ray astronomy

    NASA Technical Reports Server (NTRS)

    Dyer, P.; Bodansky, D.; Maxson, D. R.

    1978-01-01

    Gamma-ray production cross sections were measured for protons and alpha particles incident on targets consisting of nuclei of high cosmic abundance: C-12, N-14, O-16, Ne-20, Mg-24, Si-28 and Fe-56. Solid or gaseous targets were bombarded by monoenergetic beams of protons and alpha particles, and gamma rays were detected by two Ge(Li) detectors. The proton energy for each target was varied from threshold to about 24 MeV (lab); for alphas the range was from threshold to about 27 MeV. For most transitions, it was possible to measure the total cross section by placing the detectors at 30.5 deg and 109.9 deg where the fourth-order Legendre polynomial is zero. For the case of the 16O (E sub gamma = 6.13 MeV, multipolarity E3) cross sections, yields were measured at four angles. Absolute cross sections were obtained by integrating the beam current and by measuring target thicknesses and detector efficiencies. The Ge(Li) detector resolution was a few keV (although the peak widths were greater, due to Doppler broadening).

  9. Photoelectric absorption cross sections with variable abundances

    NASA Technical Reports Server (NTRS)

    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.

  10. Cross Sections From Scalar Field Theory

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Dick, Frank; Norman, Ryan B.; Nasto, Rachel

    2008-01-01

    A one pion exchange scalar model is used to calculate differential and total cross sections for pion production through nucleon- nucleon collisions. The collisions involve intermediate delta particle production and decay to nucleons and a pion. The model provides the basic theoretical framework for scalar field theory and can be applied to particle production processes where the effects of spin can be neglected.

  11. Electron impact excitation cross sections for carbon

    NASA Astrophysics Data System (ADS)

    Ganas, P. S.

    1981-04-01

    A realistic analytic atomic independent particle model is used to generate wave functions for the valence and excited states of carbon. Using these wave functions in conjunction with the Born approximation and the Russell-Saunders LS-coupling scheme, we calculate generalized oscillator strengths and integrated cross sections for various excitations from the 2p 2( 3P O) valence state.

  12. Measurements of cross sections and decay properties of the isotopes of elements 112, 114, and 116 produced in the fusion reactions 233,238 U , 242Pu , and 248Cm + 48Ca

    NASA Astrophysics Data System (ADS)

    Oganessian, Yu. Ts.; Utyonkov, V. K.; Lobanov, Yu. V.; Abdullin, F. Sh.; Polyakov, A. N.; Shirokovsky, I. V.; Tsyganov, Yu. S.; Gulbekian, G. G.; Bogomolov, S. L.; Gikal, B. N.; Mezentsev, A. N.; Iliev, S.; Subbotin, V. G.; Sukhov, A. M.; Voinov, A. A.; Buklanov, G. V.; Subotic, K.; Zagrebaev, V. I.; Itkis, M. G.; Patin, J. B.; Moody, K. J.; Wild, J. F.; Stoyer, M. A.; Stoyer, N. J.; Shaughnessy, D. A.; Kenneally, J. M.; Wilk, P. A.; Lougheed, R. W.; Il'Kaev, R. I.; Vesnovskii, S. P.

    2004-12-01

    We have studied the dependence of the production cross sections of the isotopes 282,283 112 and 286,287 114 on the excitation energy of the compound nuclei 286112 and 290114 . The maximum cross section values of the xn -evaporation channels for the reaction 238U ( 48Ca ,xn) 286-x 112 were measured to be σ3n = 2.5 +1.8 -1.1 pb and σ4n = 0.6 +1.6 -0.5 pb ; for the reaction 242Pu ( 48Ca ,xn) 290-x 114 : σ2n ˜0.5 pb , σ3n = 3.6 +3.4 -1.7 pb , and σ4n = 4.5 +3.6 -1.9 pb . In the reaction 233U ( 48Ca ,2 4n) 277 279 112 at E*=34.9±2.2 MeV we measured an upper cross section limit of σxn ⩽0.6 pb . The observed shift of the excitation energy associated with the maximum sum evaporation residue cross section σER (E*) to values significantly higher than that associated with the calculated Coulomb barrier can be caused by the orientation of the deformed target nucleus in the entrance channel of the reaction. An increase of σER in the reactions of actinide targets with 48Ca is consistent with the expected increase of the survivability of the excited compound nucleus upon closer approach to the closed neutron shell N=184 . In the present work we detected 33 decay chains arising in the decay of the known nuclei 282112 , 283112 , 286114 , 287114 , and 288114 . In the decay of 287114 (α) → 283112 (α) → 279110 (SF) , in two cases out of 22, we observed decay chains of four and five sequential α transitions that end in spontaneous fission of 271Sg ( Tα/SF = 2.4 +4.3 -1.0 min) and 267Rf ( TSF ˜2.3 h) , longer decay chains than reported previously. We observed the new nuclide 292116 ( Tα = 18 +16 -6 ms, Eα =10.66±0.07 MeV) in the irradiation of the 248Cm target at a higher energy than in previous experiments. The observed nuclear decay properties of the nuclides with Z=104 118 are compared with theoretical nuclear mass calculations and the systematic trends of spontaneous fission properties. As a whole, they give a consistent pattern of decay of the 18 even- Z

  13. Measurement of the NP Elastic Cross Section by Neutron Transmission

    NASA Astrophysics Data System (ADS)

    Daub, Brian; Kovash, Michael; Henzl, Vladimir; Shoniyozov, Khayrullo

    2010-11-01

    There are very few previous measurements of the cross section for neutron-proton elastic scattering at energies between 200 and 500 keV. To improve this situation, we used a pulsed proton beam from the Van de Graaff accelerator at the University of Kentucky to produce 200-800 keV neutrons via the ^7Li(p,n)^7Be reaction. We determined the total n-p elastic cross section by measuring the transmission of the neutron beam in samples of CH2 and carbon, using a BC501 liquid scintillator. The cross section obtained by taking ratios between normalized sample-in and sample-out yields is independent of both detector efficiency and dead time.

  14. Pion Total Cross Section in Nucleon - Nucleon Collisions

    NASA Technical Reports Server (NTRS)

    Norbury, John W.

    2009-01-01

    Total cross section parameterizations for neutral and charged pion production in nucleon - nucleon collisions are compared to experimental data over the projectile momentum range from threshold to 300 GeV. Both proton - proton and proton - neutron reactions are considered. Overall excellent agreement between parameterizations and experiment is found, except for notable disagreements near threshold. In addition, the hypothesis that the neutral pion production cross section can be obtained from the average charged pion cross section is checked. The theoretical formulas presented in the paper obey this hypothesis for projectile momenta below 500 GeV. The results presented provide a test of engineering tools used to calculate the pion component of space radiation.

  15. Quantum mechanical differential and integral cross sections for the C({sup 1}D) + H{sub 2}(ν = 0, j = 0) → CH(ν′, j′) + H reaction

    SciTech Connect

    Shen, Zhitao; Cao, Jianwei; Bian, Wensheng

    2015-04-28

    Accurate quantum dynamics calculations for the C({sup 1}D) + H{sub 2} reaction are performed using a real wave packet approach with full Coriolis coupling. The newly constructed ZMB-a ab initio potential energy surface [Zhang et al., J. Chem. Phys. 140, 234301 (2014)] is used. The integral cross sections (ICSs), differential cross sections (DCSs), and product state distributions are obtained over a wide range of collision energies. In contrast to previous accurate quantum dynamics calculations on the reproducing kernel Hilbert space potential energy surface, the present total ICS is much larger at low collision energies, yielding larger rate coefficients in better agreement with experiment and with slight inverse temperature dependence. Meanwhile, interesting nonstatistical behaviors in the DCSs are revealed. In particular, the DCSs display strong oscillations with the collision energy; forward biased product angular distribution appears when only small J partial wave contributions are included; alternate forward and backward biases emerge with very small increments of collision energy; and the rotational state-resolved DCSs show strong oscillations with the scattering angle. Nevertheless, the total DCSs can be roughly regarded as backward–forward symmetric over the whole energy range and are in reasonably good agreement with the available experimental measurements.

  16. Alpha particle induced reactions on natCr up to 39 MeV: Experimental cross-sections, comparison with theoretical calculations and thick target yields for medically relevant 52gFe production

    NASA Astrophysics Data System (ADS)

    Hermanne, A.; Adam Rebeles, R.; Tárkányi, F.; Takács, S.

    2015-08-01

    Thin natCr targets were obtained by electroplating, using 23.75 μm Cu foils as backings. In five stacked foil irradiations, followed by high resolution gamma spectroscopy, the cross sections for production of 52gFe, 49,51cumCr, 52cum,54,56cumMn and 48cumV in Cr and 61Cu,68Ga in Cu were measured up to 39 MeV incident α-particle energy. Reduced uncertainty is obtained by simultaneous remeasurement of the natCu(α,x)67,66Ga monitor reactions over the whole energy range. Comparisons with the scarce literature values and results from the TENDL-2013 on-line library, based on the theoretical code family TALYS-1.6, were made. A discussion of the production routes for 52gFe with achievable yields and contamination rates was made.

  17. The H + HeH(+) → He + H2(+) reaction from the ultra-cold regime to the three-body breakup: exact quantum mechanical integral cross sections and rate constants.

    PubMed

    De Fazio, Dario

    2014-06-21

    In this work, we present a quantum mechanical scattering study of the title reaction from 1 mK to 2000 K. Total integral cross sections and thermal rate constants are compared with previous theoretical and experimental data and with simpler theoretical models to understand the range of validity of the approximations used in the previous studies. The obtained quantum reactive observables have been found to be nearly insensitive to the roto-vibrational energy of the reactants at high temperatures. More sensitive to the reactant's roto-vibrational energy are the data in the cold and ultra-cold regimes. The implications of the new data presented here in the early universe scenario are also discussed and analyzed. PMID:24810283

  18. Theoretical Formalism To Estimate the Positron Scattering Cross Section.

    PubMed

    Singh, Suvam; Dutta, Sangita; Naghma, Rahla; Antony, Bobby

    2016-07-21

    A theoretical formalism is introduced in this article to calculate the total cross sections for positron scattering. This method incorporates positron-target interaction in the spherical complex optical potential formalism. The study of positron collision has been quite subtle until now. However, recently, it has emerged as an interesting area due to its role in atomic and molecular structure physics, astrophysics, and medicine. With the present method, the total cross sections for simple atoms C, N, and O and their diatomic molecules C2, N2, and O2 are obtained and compared with existing data. The total cross section obtained in the present work gives a more consistent shape and magnitude than existing theories. The characteristic dip below 10 eV is identified due to the positronium formation. The deviation of the present cross section with measurements at energies below 10 eV is attributed to the neglect of forward angle-discrimination effects in experiments, the inefficiency of additivity rule for molecules, empirical treatment of positronium formation, and the neglect of annihilation reactions. In spite of these deficiencies, the present results show consistent behavior and reasonable agreement with previous data, wherever available. Besides, this is the first computational model to report positron scattering cross sections over the energy range from 1 to 5000 eV. PMID:27333337

  19. Can cross sections be accurately known for priori?

    SciTech Connect

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

    2008-06-24

    Distinct maxima and minima in the neutron total cross section uncertainties were observed in our large scale covariance calculations using a spherical optical potential. In this contribution we investigate the physical origin of this oscillating structure. Specifically, we analyze the case of neutron reactions on {sup 56}Fe, for which total cross section uncertainties are characterized by the presence of five distinct minima at 0.1, 1.1, 5, 25, and 70 MeV. To investigate their origin, we calculated total cross sections by perturbing the real volume depth V{sub v} by its expected uncertainty {+-}{Delta}V{sub v}. Inspecting the effect of this perturbation on the partial wave cross sections we found that the first minimum (at 0.1 MeV) is exclusively due to the contribution of the s-wave. On the other hand, the same analysis at 1.1 MeV showed that the minimum is the result of the interplay between s-, p-, and d-waves; namely the change in the s-wave happens to be counterbalanced by changes in the p- and d-waves. Similar considerations can be extended for the third minimum, although it can be also explained in terms of the Ramsauer effect as well as the other ones (at 25 and 70 MeV). We discuss the potential importance of these minima for practical applications as well as the implications of this work for the uncertainties in total and absorption cross sections.

  20. Calculation of improved spallation cross sections

    NASA Technical Reports Server (NTRS)

    Tsao, C. H.; Silberberg, R.; Letaw, J. R.

    1985-01-01

    Several research groups have recently carried out highly precise measurements (to about 10 percent) of high-energy nuclear spallation cross sections. These measurements, above 5 GeV, cover a broad range of elements: V, Fe, Cu, Ag, Ta and Au. Even the small cross sections far off the peak of the isotopic distribution curves have been measured. The semiempirical calculations are compared with the measured values. Preliminary comparisons indicate that the parameters of our spallation relations (Silberberg and Tsao, 1973) for atomic numbers 20 to 83 need modifications, e.g. a reduced slope of the mass yield distribution, broader isotopic distributions, and a shift of the isotopic distribution toward the neutron-deficient side. The required modifications are negligible near Fe and Cu, but increase with increasing target mass.

  1. Cross sections required for FMIT dosimetry

    SciTech Connect

    Gold, R.; McElroy, W.N.; Lippincott, E.P.; Mann, F.M.; Oberg, D.L.; Roberts, J.H.; Ruddy, F.H.

    1980-05-02

    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. Inclusive jet cross section at D0

    SciTech Connect

    Bhattacharjee, M.

    1996-09-01

    Preliminary measurement of the central ({vert_bar}{eta}{vert_bar} {<=} 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 {ital pb}{sup -1}) and 1994-1995 (90 {ital pb}{sup -1}) data samples are presented. Comparisons to Next-to-Leading Order (NLO) Quantum Chromodynamics (QCD) calculations are made.

  3. Absolute photoionization cross sections of atomic oxygen

    NASA Technical Reports Server (NTRS)

    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.

  4. Absolute photoionization cross sections of atomic oxygen

    NASA Technical Reports Server (NTRS)

    Samson, J. A. R.; Pareek, P. N.

    1982-01-01

    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.

  5. {sup 231}Pa photofission cross section

    SciTech Connect

    Soldatov, A.S.; Rudnikov, V.E.; Smirenkin, G.N.

    1995-12-01

    The measurements of the {sup 231}Pa yield and cross section photofission in the energy range 7-9 MeV are presented. These measurements are a continuation of similar measurements performed for the {gamma}-ray energy range 4.8-7 MeV. The entire collection of experimental data which combine the results obtained in the present work and in Ref. 1 was analyzed.

  6. How to Calculate Colourful Cross Sections Efficiently

    SciTech Connect

    Gleisberg, Tanju; Hoeche, Stefan; Krauss, Frank

    2008-09-03

    Different methods for the calculation of cross sections with many QCD particles are compared. To this end, CSW vertex rules, Berends-Giele recursion and Feynman-diagram based techniques are implemented as well as various methods for the treatment of colours and phase space integration. We find that typically there is only a small window of jet multiplicities, where the CSW technique has efficiencies comparable or better than both of the other two methods.

  7. Inclusive jet cross section measurement at CDF

    SciTech Connect

    Pagliarone, C.

    1996-08-01

    The CDF Collaboration has measured the inclusive jet cross section using 1992-93 collider data at 1.8 TeV. The CDF measurement is in very good agreement with NLO QCD predictions for transverse energies (E{sub T}) below 200 GeV. However, it is systematically higher than NLO QCD predictions for E{sub T} above 200 GeV.

  8. Improved activation cross sections for vanadium and titanium

    SciTech Connect

    Muir, D.W.; Arthur, E.D.

    1983-01-01

    Vanadium alloys such as V-20Ti and V-Cr-Ti are attractive candidates for use as structural materials in fusion-reactor blankets. The virtual absence of long-lived activation products in these alloys suggest the possibility of reprocessing on an intermediate time scale. We have employed the modern Hauser-Feshbach nuclear-model code GNASH to calculate cross sections for neutron-activation reactions in /sup 50/V and /sup 51/V, to allow a more accurate assessment of induced radioactivity in vanadium alloys. In addition, cross sections are calculated for the reactions /sup 46/Ti(n,2n) and /sup 45/Ti(n,2n) in order to estimate the production of /sup 44/Ti, a 1.2-MeV gamma-ray source with a half-life of 47 years.

  9. Quality Quantification of Evaluated Cross Section Covariances

    SciTech Connect

    Varet, S.; Dossantos-Uzarralde, P.

    2015-01-15

    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 {sup 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.

  10. Fission cross section calculations of actinides with EMPIRE code

    SciTech Connect

    Sin, M.; Oblozinsky, P.; Herman,M.; Capote,R.

    2010-04-30

    The cross sections of the neutron induced reactions on {sup 233,234,236}U, {sup 237}Np, {sup 238,242}Pu, {sup 241,243}Am, {sup 242,246}Cm carried out in the energy range 1 keV-20 MeV with EMPIRE code are presented, emphasizing the fission channel. Beside a consistent, accurate set of evaluations, the paper contains arguments supporting the choice of the reaction models and input parameters. A special attention is paid to the fission parameters and their uncertainties.

  11. Hydroxyl radical reaction rate coefficients as a function of temperature and IR absorption cross sections for CF3CH=CH2 (HFO-1243zf), potential replacement of CF3CH2F (HFC-134a).

    PubMed

    González, Sergio; Jiménez, Elena; Ballesteros, Bernabé; Martínez, Ernesto; Albaladejo, José

    2015-04-01

    CF3CH=CH2 (hydrofluoroolefin, HFO-1243zf) is a potential replacement of high global-warming potential (GWP) hydrofluorocarbon (HFC-134a, CF3CFH2). Both the atmospheric lifetime and the radiative efficiency of HFO-1243zf are parameters needed for estimating the GWP of this species. Therefore, the aim of this work is (i) to estimate the atmospheric lifetime of HFO-1243zf from the reported OH rate coefficients, k OH, determined under tropospheric conditions and (ii) to calculate its radiative efficiency from the reported IR absorption cross sections. The OH rate coefficient at 298 K also allows the estimation of the photochemical ozone creation potential (ε(POCP)). The pulsed laser photolysis coupled to a laser-induced fluorescence technique was used to determine k OH for the reaction of OH radicals with HFO-1243zf as a function of pressure (50-650 Torr of He) and temperature (263-358 K). Gas-phase IR spectra of HFO-1243zf were recorded at room temperature using a Fourier transform IR spectrometer between 500 and 4,000 cm(-1). At all temperatures, k OH did not depend on bath gas concentration (i.e., on the total pressure between 50 and 650 Torr of He). A slight but noticeable T dependence of k OH was observed in the temperature range investigated. The observed behavior is well described by the following Arrhenius expression: k OH(T) = (7.65 ± 0.26) × 10(-13) exp [(165 ± 10) / T] cm(3) molecule(-1) s(-1). Negligible IR absorption of HFO-1243zf was observed at wavenumbers greater than 1,700 cm(-1). Therefore, IR absorption cross sections, [Formula: see text], were determined in the 500-1,700 cm(-1) range. Integrated [Formula: see text] were determined between 650 and 1,800 cm(-1) for comparison purposes. The main diurnal removal pathway for HFO-1243zf is the reaction with OH radicals, which accounts for 64% of the overall loss by homogeneous reactions at 298 K. Globally, the lifetime due to OH reaction (τ OH) was estimated to be 8.7 days under

  12. Preliminary cross section of Englebright Lake sediments

    USGS Publications Warehouse

    Snyder, Noah P.; Hampton, Margaret A.

    2003-01-01

    Overview -- The Upper Yuba River Studies Program is a CALFED-funded, multidisciplinary investigation of the feasibility of introducing anadromous fish species to the Yuba River system upstream of Englebright Dam. Englebright Lake (Figure 1 on poster) is a narrow, 14-km-long reservoir located in the northern Sierra Nevada, northeast of Marysville, CA. The dam was completed in 1941 for the primary purpose of trapping sediment derived from mining operations in the Yuba River watershed. Possible management scenarios include lowering or removing Englebright Dam, which could cause the release of stored sediments and associated contaminants, such as mercury used extensively in 19th-century hydraulic gold mining. Transport of released sediment to downstream areas could increase existing problems including flooding and mercury bioaccumulation in sport fish. To characterize the extent, grain size, and chemistry of this sediment, a coring campaign was done in Englebright Lake in May and June 2002. More than twenty holes were drilled at 7 different locations along the longitudinal axis of the reservoir (Figure 4 on poster), recovering 6 complete sequences of post-reservoir deposition and progradation. Here, a longitudinal cross section of Englebright Lake is presented (Figure 5 on poster), including pre-dam and present-day topographic profiles, and sedimentologic sections for each coring site. This figure shows the deltaic form of the reservoir deposit, with a thick upper section consisting of sand and gravel overlying silt, a steep front, and a thinner lower section dominated by silt. The methodologies used to create the reservoir cross section are discussed in the lower part of this poster.

  13. Cross Sections for the Reactions e+e to K+ K- pi+pi-, K+ K- pi0pi0, and K+ K- K+ K- Measured Using Initial-State Radiation

    SciTech Connect

    Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Milanes, D.A.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Brown, D.N.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; Osipenkov, I.L.; Koch, H.; Schroeder, T.; Asgeirsson, D.J.; /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Trieste /INFN, Trieste /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /INFN, Ferrara /Ferrara U. /Frascati /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /INFN, Trieste /Trieste U. /INFN, Trieste /INFN, Genoa /Genoa U. /Indian Inst. Tech., Guwahati /Harvard U. /Harvey Mudd Coll. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa State U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U., Comp. Sci. Dept. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Milan /Milan U. /Mississippi U. /Montreal U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Naples /Naples U. /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /INFN, Trieste /INFN, Trieste /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Padua /Padua U. /Paris U., VI-VII /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Perugia /Perugia U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /INFN, Pisa /Princeton U. /INFN, Trieste /INFN, Trieste /INFN, Trieste /Trieste U. /INFN, Trieste /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /INFN, Trieste /INFN, Trieste /INFN, Rome /Rome U. /Rostock U. /Rutherford /DAPNIA, Saclay /SLAC /South Carolina U. /Southern Methodist U. /Stanford U., Phys. Dept. /SUNY, Albany /Tel Aviv U. /Tennessee U. /Texas U. /Texas U., Dallas /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /INFN, Trieste /Trieste U. /Valencia U., IFIC /Victoria U. /Warwick U. /Wisconsin U., Madison

    2011-08-19

    We study the processes e{sup +}e{sup -} {yields} K{sup +}K{sup -}{pi}{sup +}{pi}-{gamma}, K{sup +}K{sup -}{pi}{sup 0}{pi}{sup 0}{gamma}, and K{sup +}K{sup -}K{sup +}K{sup -}{gamma}, where the photon is radiated from the initial state. About 84000, 8000, and 4200 fully reconstructed events, respectively, are selected from 454 fb{sup -1} of BABAR data. The invariant mass of the hadronic final state defines the e{sup +}e{sup -} center-of-mass energy, so that the K{sup +}K{sup -}{pi}{sup +}{pi}{sup -}{gamma} data can be compared with direct measurements of the e{sup +}e{sup -} {yields} K{sup +}K{sup -}{pi}{sup +}{pi}{sup -} reaction. No direct measurements exist for the e{sup +}e{sup -} {yields} K{sup +}K{sup -}{pi}{sup 0}{pi}{sup 0} or e{sup +}e{sup -} {yields} K{sup +}K{sup -}K{sup +}K{sup -} reactions, and we present an update of our previous result with doubled statistics. Studying the structure of these events, we find contributions from a number of intermediate states, and extract their cross sections. In particular, we perform a more detailed study of the e{sup +}e{sup -} {yields} {phi}(1020){pi}{pi}{gamma} reaction, and confirm the presence of the Y (2175) resonance in the {phi}(1020)f{sub 0}(980) and K{sup +}K{sup -} f{sub 0}(980) modes. In the charmonium region, we observe the J/{psi} in all three final states and in several intermediate states, as well as the {phi}(2S) in some modes, and measure the corresponding branching fractions.

  14. The calculation of radar cross sections

    NASA Astrophysics Data System (ADS)

    Pizer, R.

    1980-04-01

    The FORTRAN program CHAOS, used for calculating cross sections is described including the physical approximations used to simplify Maxwell's equations. The scattering bodies are extended to both open and closed surfaces. The numerical methods used are supplied. The problems of wire junctions, of finite conductivity and the attaching of lumped loads to the structure are considered. Techniques for dealing with bodies having rotational or left-right symmetries are examined as well as the sparse matrix approximation and the complex frequency version of CHAOS. The formula used to calculate the impedance matrix elements, and the conventions adopted concerning coordinate systems and polarization are included.

  15. Correlation cross sections along the international border

    SciTech Connect

    Martiniuk, C.D. ); Le Fever, J.A.; Anderson, S.B. )

    1991-06-01

    The Manitoba-North Dakota (Canada-US) stratigraphic correlation project is a joint study between the Petroleum Branch of Manitoba Energy and Mines and the North Dakota Geological Survey. It is an attempt to correlate the differing stratigraphic terminologies established in the two jurisdictions by providing a reference cross section across the international boundary. The study involves the subsurface correlation of logs of the Paleozoic and Mesozoic sequences in the Manitoba and North Dakota portions of the Williston basin. The Paleozoic and Mesozoic sequences are subdivided for presentation into the following stratigraphic intervals: (a) Cambrian-Ordovician-Silurian, (b) Devonian, (c) Mississippian, (d) Jurassic, and (e) Cretaceous. Wireline logs show the actual stratigraphic correlations. A nomenclature chart is also presented from each sequence. In addition, the sections include a generalized description of lithologies, thicknesses, environments of deposition, and petroleum potential for each geographic area.

  16. Stellar neutron capture cross sections of the Lu isotopes

    SciTech Connect

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

    2006-01-15

    The neutron capture cross sections of {sup 175}Lu and {sup 176}Lu have been measured in the energy range 3-225 keV at the Karlsruhe 3.7 MV Van de Graaff accelerator. Neutrons were produced via the {sup 7}Li(p,n){sup 7}Be reaction by bombarding metallic Li targets with a pulsed proton beam, and capture events were registered with the Karlsruhe 4{pi} barium fluoride detector. The cross sections were determined relative to the gold standard using isotopically enriched as well as natural lutetium oxide samples. Overall uncertainties of {approx}1% could be achieved in the final cross section ratios to the gold standard, about a factor of 5 smaller than in previous works. Maxwellian averaged neutron capture cross sections were calculated for thermal energies between kT = 8 and 100 keV. These values are systematically larger by {approx}7% than those reported in recent evaluations. These results are of crucial importance for the assessment of the s-process branchings at A 175/176.

  17. High-mass dijet cross sections in photoproduction at HERA

    NASA Astrophysics Data System (ADS)

    Chekanov, S.; Derrick, M.; Krakauer, D.; Magill, S.; Musgrave, B.; Pellegrino, A.; Repond, J.; Yoshida, R.; Mattingly, M. C. K.; Antonioli, P.; Bari, G.; Basile, M.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Cara Romeo, G.; Cifarelli, L.; Cindolo, F.; Contin, A.; Corradi, M.; De Pasquale, S.; Giusti, P.; Iacobucci, G.; Levi, G.; Margotti, A.; Massam, T.; Nania, R.; Palmonari, F.; Pesci, A.; Sartorelli, G.; Zichichi, A.; Aghuzumtsyan, G.; Bartsch, D.; Brock, I.; Crittenden, J.; Goers, S.; Hartmann, H.; Hilger, E.; Irrgang, P.; Jakob, H.-P.; Kappes, A.; Katz, U. F.; Kerger, R.; Kind, O.; Paul, E.; Rautenberg, J.; Renner, R.; Schnurbusch, H.; Stifutkin, A.; Tandler, J.; Voss, K. C.; Weber, A.; Wessoleck, H.; Bailey, D. S.; Brook, N. H.; Cole, J. E.; Foster, B.; Heath, G. P.; Heath, H. F.; Robins, S.; Rodrigues, E.; Scott, J.; Tapper, R. J.; Wing, M.; Capua, M.; Mastroberardino, A.; Schioppa, M.; Susinno, G.; Jeoung, H. Y.; Kim, J. Y.; Lee, J. H.; Lim, I. T.; Ma, K. J.; Pac, M. Y.; Caldwell, A.; Helbich, M.; Liu, X.; Mellado, B.; Paganis, S.; Schmidke, W. B.; Sciulli, F.; Chwastowski, J.; Eskreys, A.; Figiel, J.; Olkiewicz, K.; Przybycień, M. B.; Stopa, P.; Zawiejski, L.; Bednarek, B.; Grabowska-Bold, I.; Jeleń, K.; Kisielewska, D.; Kowal, A. M.; Kowal, M.; Kowalski, T.; Mindur, B.; Przybycień, M.; Rulikowska-Zarȩbska, E.; Suszycki, L.; Szuba, D.; Szuba, J.; Kotański, A.; Słomiński, W.; Bauerdick, L. A. T.; Behrens, U.; Borras, K.; Chiochia, V.; Dannheim, D.; Desler, K.; Drews, G.; Fourletova, J.; Fox-Murphy, A.; Fricke, U.; Geiser, A.; Goebel, F.; Göttlicher, P.; Graciani, R.; Haas, T.; Hain, W.; Hartner, G. F.; Hillert, S.; Kötz, U.; Kowalski, H.; Labes, H.; Lelas, D.; Löhr, B.; Mankel, R.; Martens, J.; Martínez, M.; Moritz, M.; Notz, D.; Petrucci, M. C.; Polini, A.; Schneekloth, U.; Selonke, F.; Stonjek, S.; Surrow, B.; Whitmore, J. J.; Wichmann, R.; Wolf, G.; Youngman, C.; Zeuner, W.; Coldewey, C.; Lopez-Duran Viani, A.; Meyer, A.; Schlenstedt, S.; Barbagli, G.; Gallo, E.; Genta, C.; Pelfer, P. G.; Bamberger, A.; Benen, A.; Coppola, N.; Markun, P.; Raach, H.; Wölfle, S.; Bell, M.; Bussey, P. J.; Doyle, A. T.; Glasman, C.; Hanlon, S.; Lee, S. W.; Lupi, A.; McCance, G. J.; Saxon, D. H.; Skillicorn, I. O.; Bodmann, B.; Holm, U.; Salehi, H.; Wick, K.; Ziegler, A.; Ziegler, Ar.; Carli, T.; Gialas, I.; Klimek, K.; Lohrmann, E.; Milite, M.; Collins-Tooth, C.; Foudas, C.; Gonçalo, R.; Long, K. R.; Metlica, F.; Miller, D. B.; Tapper, A. D.; Walker, R.; Cloth, P.; Filges, D.; Kuze, M.; Nagano, K.; Tokushuku, K.; Yamada, S.; Yamazaki, Y.; Barakbaev, A. N.; Boos, E. G.; Pokrovskiy, N. S.; Zhautykov, B. O.; Ahn, S. H.; Lee, S. B.; Park, S. K.; Lim, H.; Son, D.; Barreiro, F.; García, G.; González, O.; Labarga, L.; del Peso, J.; Redondo, I.; Terrón, J.; Vázquez, M.; Barbi, M.; Bertolin, A.; Corriveau, F.; Ochs, A.; Padhi, S.; Stairs, D. G.; St-Laurent, M.; Tsurugai, T.; Antonov, A.; Bashkirov, V.; Danilov, P.; Dolgoshein, B. A.; Gladkov, D.; Sosnovtsev, V.; Suchkov, S.; Dementiev, R. K.; Ermolov, P. F.; Golubkov, Yu. A.; Katkov, I. I.; Khein, L. A.; Korotkova, N. A.; Korzhavina, I. A.; Kuzmin, V. A.; Levchenko, B. B.; Lukina, O. Yu.; Proskuryakov, A. S.; Shcheglova, L. M.; Solomin, A. N.; Vlasov, N. N.; Zotkin, S. A.; Bokel, C.; Engelen, J.; Grijpink, S.; Koffeman, E.; Kooijman, P.; Maddox, E.; Schagen, S.; Tassi, E.; Tiecke, H.; Tuning, N.; Velthuis, J. J.; Wiggers, L.; de Wolf, E.; Brümmer, N.; Bylsma, B.; Durkin, L. S.; Gilmore, J.; Ginsburg, C. M.; Kim, C. L.; Ling, T. Y.; Boogert, S.; Cooper-Sarkar, A. M.; Devenish, R. C. E.; Ferrando, J.; Matsushita, T.; Rigby, M.; Ruske, O.; Sutton, M. R.; Walczak, R.; Brugnera, R.; Carlin, R.; Dal Corso, F.; Dusini, S.; Garfagnini, A.; Limentani, S.; Longhin, A.; Parenti, A.; Posocco, M.; Stanco, L.; Turcato, M.; Adamczyk, L.; Oh, B. Y.; Saull, P. R. B.; Iga, Y.; D'Agostini, G.; Marini, G.; Nigro, A.; Cormack, C.; Hart, J. C.; McCubbin, N. A.; Heusch, C.; Park, I. H.; Pavel, N.; Abramowicz, H.; Dagan, S.; Gabareen, A.; Kananov, S.; Kreisel, A.; Levy, A.; Abe, T.; Fusayasu, T.; Kohno, T.; Umemori, K.; Yamashita, T.; Hamatsu, R.; Hirose, T.; Inuzuka, M.; Kitamura, S.; Matsuzawa, K.; Nishimura, T.; Arneodo, M.; Cartiglia, N.; Cirio, R.; Costa, M.; Ferrero, M. I.; Maselli, S.; Monaco, V.; Peroni, C.; Ruspa, M.; Sacchi, R.; Solano, A.; Staiano, A.; Galea, R.; Koop, T.; Levman, G. M.; Martin, J. F.; Mirea, A.; Sabetfakhri, A.; Butterworth, J. M.; Gwenlan, C.; Hall-Wilton, R.; Hayes, M. E.; Heaphy, E. A.; Jones, T. W.; Lane, J. B.; Lightwood, M. S.; West, B. J.; Ciborowski, J.; Ciesielski, R.; Grzelak, G.; Nowak, R. J.; Pawlak, J. M.; Smalska, B.; Sztuk, J.; Tymieniecka, T.; Ukleja, A.; Ukleja, J.; Zakrzewski, J. A.; Żarnecki, A. F.; Adamus, M.; Plucinski, P.; Eisenberg, Y.; Gladilin, L. K.; Hochman, D.; Karshon, U.; Breitweg, J.; Chapin, D.; Cross, R.; Kçira, D.; Lammers, S.; Reeder, D. D.; Savin, A. A.; Smith, W. H.; Deshpande, A.; Dhawan, S.; Hughes, V. W.; Straub, P. B.; Bhadra, S.; Catterall, C. D.; Fourletov, S.; Menary, S.; Soares, M.; Standage, J.; ZEUS Collaboration

    2002-04-01

    Dijet differential cross sections for the reaction e+p→e++ jet + jet + X in the photoproduction regime have been measured with the ZEUS detector at HERA using an integrated luminosity of 42.7 pb-1. The cross sections are given for photon-proton centre-of-mass energies in the range 134cross sections as a function of the dijet mass, Mjj, and of the dijet angular variables have been measured for 47cross section for Z0 photoproduction of σe+p→e+Z0X<5.9 pb. Upper limits on the photoproduction of new heavy resonances decaying into two jets are also presented for masses in the range between 60 GeV and 155 GeV.

  18. Stellar neutron capture cross sections of the tin isotopes

    SciTech Connect

    Wisshak, K.; Voss, F.; Theis, C.; Kaeppeler, F.; Guber, K.; Kazakov, L.; Kornilov, N.; Reffo, G.

    1996-09-01

    The neutron capture cross sections of {sup 114}Sn, {sup 115}Sn, {sup 116}Sn, {sup 117}Sn, {sup 118}Sn, and {sup 120}Sn were measured in the energy range from 3 to 225 keV at the Karlsruhe 3.75 MV Van de Graaff accelerator. Neutrons were produced via the {sup 7}Li({ital p},{ital n}){sup 7}Be reaction using a pulsed proton beam. Capture events were registered with the Karlsruhe 4{pi} barium fluoride detector. The experiment was complicated by the small ({ital n},{gamma}) cross sections of the proton magic tin isotopes and by the comparably low enrichment of the rare isotopes {sup 114}Sn and {sup 115}Sn. Despite significant corrections for capture of scattered neutrons and for isotopic impurities, the high efficiency and the spectroscopic quality of the BaF{sub 2} detector allowed the determination of the cross-section ratios with overall uncertainties of 1{endash}2{percent}, five times smaller compared to existing data. Based on these results, Maxwellian averaged ({ital n},{gamma}) cross sections were calculated for thermal energies between {ital kT}=10 and 100 keV. These data are used for a discussion of the solar tin abundance and for an improved determination of the isotopic {ital s}- and {ital r}-process components. {copyright} {ital 1996 The American Physical Society.}

  19. Windowed multipole for cross section Doppler broadening

    NASA Astrophysics Data System (ADS)

    Josey, C.; Ducru, P.; Forget, B.; Smith, K.

    2016-02-01

    This paper presents an in-depth analysis on the accuracy and performance of the windowed multipole Doppler broadening method. The basic theory behind cross section data is described, along with the basic multipole formalism followed by the approximations leading to windowed multipole method and the algorithm used to efficiently evaluate Doppler broadened cross sections. The method is tested by simulating the BEAVRS benchmark with a windowed multipole library composed of 70 nuclides. Accuracy of the method is demonstrated on a single assembly case where total neutron production rates and 238U capture rates compare within 0.1% to ACE format files at the same temperature. With regards to performance, clock cycle counts and cache misses were measured for single temperature ACE table lookup and for windowed multipole. The windowed multipole method was found to require 39.6% more clock cycles to evaluate, translating to a 7.9% performance loss overall. However, the algorithm has significantly better last-level cache performance, with 3 fewer misses per evaluation, or a 65% reduction in last-level misses. This is due to the small memory footprint of the windowed multipole method and better memory access pattern of the algorithm.

  20. Actinide Targets for Neutron Cross Section Measurements

    SciTech Connect

    John D. Baker; Christopher A. McGrath

    2006-10-01

    The Advanced Fuel Cycle Initiative (AFCI) and the Generation IV Reactor Initiative have demonstrated a lack of detailed neutron cross-sections for certain "minor" actinides, those other than the most common (235U, 238U, and 239Pu). For some closed-fuel-cycle reactor designs more than 50% of reactivity will, at some point, be derived from "minor" actinides that currently have poorly known or in some cases not measured (n,?) and (n,f) cross sections. A program of measurements under AFCI has begun to correct this. One of the initial hurdles has been to produce well-characterized, highly isotopically enriched, and chemically pure actinide targets on thin backings. Using a combination of resurrected techniques and new developments, we have made a series of targets including highly enriched 239Pu, 240Pu, and 242Pu. Thus far, we have electrodeposited these actinide targets. In the future, we plan to study reductive distillation to achieve homogeneous, adherent targets on thin metal foils and polymer backings. As we move forward, separated isotopes become scarcer, and safety concerns become greater. The chemical purification and electodeposition techniques will be described.