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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. 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.

  7. 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.

  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. 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.

  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. 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.

  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

    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

  20. 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.

  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. 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.

  4. 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.

  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. 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.

  14. 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.

  15. 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.

  16. 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.

  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. 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.

  5. 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

  6. 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.

  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. 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.

  13. 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.

  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. 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.

  17. 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.

  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. 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.

  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. 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.

  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. 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.

  14. 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.

  15. 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.

  16. 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.

  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. 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.

  11. 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)

  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. 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.

  15. 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°.

  16. 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)

  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. 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)

  1. 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.

  2. 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.

  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. 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

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  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. 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.

  4. 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.

  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

    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.

  7. 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

  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. 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.

  10. 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.

  11. 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.

  12. 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.

  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. 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.

  16. 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.

  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. 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.

  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. 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.

  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. 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.

  8. 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.

  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 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  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. 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.

  6. 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

  7. 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.

  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. 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.

  11. 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

  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. 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

  6. 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.

  7. 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

  8. 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

  9. 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.

  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 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.

  17. 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.

  18. 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

  19. 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

  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. 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

  4. 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.

  5. 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$^\\circ$.

  6. 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.

  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.