Inelastic neutron spectra and cross sections for 238 U
Kornilov, N.V.; Kagalenko, A.V.
1994-01-01
The report discusses the experimental facilities of IPPE, results of spectra and cross sections investigations. The problems of existing data libraries were highlighted. Some of these problems for example, inelastic spectra at high energy may be solved by correct theoretical calculation. Others like level cross sections at E > 2 MeV and the possible structure of excitation function for group levels between 0.5 to 0.85 MeV demand new experimental efforts. 21 refs., 11 figs., 5 tabs
Displacement cross sections and PKA spectra: tables and applications
Doran, D.G.; Graves, N.J.
1976-12-01
Damage energy cross sections to 20 MeV are given for aluminum, vanadium, chromium, iron, nickel, copper, zirconium, niobium, molybdenum, tantalum, tungsten, lead, and 18Cr10Ni stainless steel. They are based on ENDF/B-IV nuclear data and the Lindhard energy partition model. Primary knockon atom (PKA) spectra are given for aluminum, iron, niobium, tantalum, and lead for neutron energies up to 15 MeV at approximately one-quarter lethargy intervals. The contributions of various reactions to both the displacement cross sections (taken to be proportional to the damage energy cross sections) and the PKA spectra are presented graphically. Spectral-averaged values of the displacement cross sections are given for several spectra, including approximate maps for the Experimental Breeder Reactor-II (EBR-II) and several positions in the Fast Test Reactor (FTR). Flux values are included to permit estimation of displacement rates. Graphs show integral PKA spectra for the five metals listed above for neutron spectra corresponding to locations in the EBR-II, the High Flux Isotope Reactor (HFIR), and a conceptual fusion reactor (UWMAK-I). Detailed calculations are given only for cases not previously documented. Uncertainty estimates are included
Influence of cross-section structure on unfolded neutron spectra
Ertek, C.; Vlasov, M.F.; Cross, B.; Smith, P.M.
1979-01-01
The influence of cross-section structure on neutron spectra unfolded by multiple foil activation technique, SAND-II case, has been studied. For three reactions with evident structure in neutron cross-section above threshold: 27Al(n,α)24Na, 31P(n,p)31Si and 32S(n,p)32P, two remarkably different sets of evaluated data were selected from the available evaluations; one set of data was ''smooth'', the structure having been averaged over by a smooth curve; the other set was ''sharp'' with structure given in detail. These data were used in unfolding procedure together with other reactions, the same in both cases (as well as input spectra and measured reaction rates). It was found that during unfolding calculations less iteration steps were needed to unfold the neutron flux spectrum with the set of ''sharp'' data. In case of ''smooth'' data it was difficult to obtain an agreement between measured and calculated activity values even by increasing the number of iteration steps. Contrary to expectations, considerable deformation of unfolded neutron flux spectrum has been observed in the case of the ''smooth'' data set. (author)
Stephens, J.R.
1998-09-01
Measurements of the ultraviolet autofluorescence spectra and absolute cross sections of the Bacillus anthracis (Ba) simulants Bacillus globigii (Bg), Bacillus megaterium (Bm), Bacillus subtilis (Bs), and Bacillus cereus (Bc) were measured. Fluorescence spectra and cross sections of pine pollen (Pina echinata) were measured for comparison. Both dried vegetative cells and spores separated from the sporulated vegetative material were studied. The spectra were obtained by suspending a small number (<10) of particles in air in our Single Particle Spectroscopy Apparatus (SPSA), illuminating the particles with light from a spectrally filtered arc lamp, and measuring the fluorescence spectra of the particles. The illumination was 280 nm (20 nm FWHM) and the fluorescence spectra was measured between 300 and 450 nm. The fluorescence cross section of vegetative Bg peaks at 320 nm with a maximum cross section of 5 X 10{sup -14} cm{sup 2}/sr-nm-particle while the Bg spore fluorescence peaks at 310 nm with peak fluorescence of 8 X 10{sup -15} cm{sup 2}/sr-nm-particle. Pine pollen particles showed a higher fluorescence peaking at 355 nm with a cross section of 1.7 X 10{sup -13} cm{sup 2}/sr-nm-particle. Integrated cross sections ranged from 3.0 X 10{sup -13} for the Bg spores through 2.25 X 10{sup -12} (cm{sup 2}/sr-particle) for the vegetative cells.
CASTHY, Statistical Model for Neutron Cross-Sections and Gamma-Ray Spectra
Igarasi, Sin-iti; Fukahori, Tokio
1998-01-01
Description of program or function: CASTHY calculates neutron cross sections of total, shape elastic scattering and compound nucleus formation with the optical model, and compound elastic, inelastic and capture cross sections by the statistical model. The other cross sections, such as (n,2n), (n,p), (n,f) reactions are treated as cross sections of competing processes, and their sum is given through input data. Capture gamma-ray spectra can also be calculated. The branching ratio for primary transition can be treated in a particular way, if required
Evaluation of fission spectra and cross sections by zero-leakage core experiments
Iijima, T.; Mukaiyama, T.
1979-01-01
A series of unit k-infinity core experiments were performed in FCA of JAERI to obtain the information on the equivalence of 239 Pu to 235 U in fast reactors, and to examine the inelastic slowing down cross section of 238 U. Three assemblies were built. Each assembly consists of a test zone (about 44l) of nearly unit k-infinity, a 20% enriched uranium driver and a natural uranium blanket. Assembly IV-1 (first built in 1969 and rebuilt in 1972) is an all uranium system, and Assemblies IV-1-P, IV-1-P' have a plutonium/natural uranium test zone. Three assemblies are nearly the same from the view-point of the slowing down cross section in the main energy region of the neutron spectrum, since 238 U occupies the most part of the composition. The main difference between Assembly IV-1 and the latter two is the difference in the fissile material. Fission rate ratios and k-infinity values were measured to obtain knowledge of the fission spectra and cross sections important for the criticality. In order to evaluate the inelastic slowing down cross section of 238 U, neutron spectra were measured with various methods. The analysis was done with four cross section sets. The agreement of k-infinity values between the experiment and the calculation is unsatisfactory, especially for Pu/NU systems
MODESTY, Statistical Reaction Cross-Sections and Particle Spectra in Decay Chain
Mattes, W.
1977-01-01
1 - Nature of the physical problem solved: Code MODESTY calculates all energetically possible reaction cross sections and particle spectra within a nuclear decay chain. 2 - Method of solution: It is based on the statistical nuclear model following the method of Uhl (reference 1) where the optical model is used in the calculation of partial widths and the Blatt-Weisskopf single particle model for gamma rays
Young, P.G.; Arthur, E.D.
1977-11-01
A new multistep Hauser--Feshbach code that includes corrections for preequilibrium effects is described. The code can calculate up to 60 decay reactions (cross sections and energy spectra) in one computation, and thereby provide considerable flexibility for handling processes with complicated reaction chains. Input parameter setup, problem output, and subroutine descriptions are given along with a sample problem calculation. A brief theoretical description is also included. 8 figures, 3 tables
ZZ DOSCROS, Neutron Cross-Section Library for Spectra Unfolding and Integral Parameter Evaluation
Zijp, Willem L.; Nolthenius, Henk J.; Rieffe, Henk Ch.
1987-01-01
1 - Description of problem or function: Format: SAND-II; Number of groups: 640 fine group cross section values; Nuclides: Li, B, F, Na, Mg, Al, S, Sc, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Nb, Mo, Rh, Pd, Ag, In, Sb, I, Cs, La, Eu, Sm, Dy, Lu, Ta, W, Re, Au, Th, U, Np, Pu. Origin: ENDF/B-V mainly, ENDF/B-IV, INDL/V. This library forms in combination with the DAMSIG81 library a convenient source of evaluated energy dependent cross section sets which may be used in the determination of neutron spectra by means of adjustment (or unfolding) procedures or which can be used for the determination of integral parameters (such as damage-to-activation ratio) useful in characterising the neutron spectra. The energy dependent fine group cross section data are presented in a 640 group structure of the SAND-II type. This group structure has 45 energy groups per energy decade below 1 MeV and a group width of 100 KeV above 1 MeV. The total energy span of this group structure is from 10 -10 MeV to 20 MeV. The library has the SAND-II format, which implies that a special part of the library has to contain cover cross section data sets. These cross section data sets are required in the SAND-II program for taking into account the influence of special detector surroundings which may be used during an irradiation. 2 - Method of solution: The selection of the reactions from the evaluated nuclear data libraries was determined by various properties of the reactions for neutron metrology. For this reason all the well- known reactions of the ENDF/B-V dosimetry file are included but these data are supplemented with cross section sets for less well known metrology reactions which may become of interest
Testing of the IRDF-90 cross-section library in benchmark neutron spectra
Nolthenius, H.J.; Zsolnay, E.M.; Szondi, E.J.
1993-09-01
The new version of the International Reactor Dosimetry File IRDF-90 (called ''Version April 1993'') has been tested by calculation of average cross-sections and their uncertainties in a coarse three energy group structure and by neutron spectrum adjustments in reference neutron spectra. This paper presents the results obtained and compares them with the corresponding ones of the old IRDF-85 and with the data of the Nuclear Data Guide for Reactor Neutron Metrology. The applicability of the new library in the field of neutron metrology is discussed. (orig.)
Measurement of keV-neutron capture cross sections and capture gamma-ray spectra of Er isotopes
Harun-Ar-Rashid, A.K.M.; Igashira, Masayuki; Ohsaki, Toshiro
2000-01-01
Neutron capture cross sections and capture γ-ray spectra of 166,167, 168 Er were measured in the energy region of 10 to 550 keV. The measurements were performed with a pulsed 7 Li(p,n) 7 Be neutron source and a large anti-Compton NaI(Tl) γ-ray spectrometer. A pulse-height weighting technique and the standard capture cross sections of gold were used to derive the capture cross sections. The errors of the derived cross sections were about 5%. The present results were compared with other measurements and evaluations. The observed capture γ-ray pulse-height spectra were unfolded to obtain the corresponding γ-ray spectra. An anomalous shoulder was observed around 3 MeV in each of the capture γ-ray spectra. (author)
Mass spectra and fusion cross sections for 20Ne+24Mg interaction at 55 and 85 MeV
Grotowski, K.; Belery, P.; Delbar, T.; El Masri, Y.; Gregoire, G.; Janssens, R.; Vervier, J.; Paic, G.; Albinska, M.; Albinski, J.; Kopta, S.; Kozik, T.; Planeta, R.
1981-01-01
Inclusive γ spectra from the 20 Ne+ 24 Mg interaction have been measured using 55- and 85-MeV 20 Ne ions. The identification of γ lines allows the determination of mass spectra in the region 12< or =A< or =43. Experimental results are compared with statistical model calculations. The total reaction and fusion cross sections are extracted. Cross sections for inelastic scattering, few nucleon transfers, and deep inelastic scattering are estimated
Seth, S.; Brunson, G.; Gmuer, K.; Jermann, M.; McCombie, C.; Richmond, R.; Schmocker, U.
1979-01-01
This paper relates the checking of integral data of steel and iron in fast reactor lattices. The fully-rodded GCFR benchmark lattice of the zero-energy reactor PROTEUS was successively modified by replacing the PuO 2 -UO 2 fuel rods by steel-18/8 or steel-37 (iron) rods. The neutron spectra of the modified lattices in fact have median energies close to that of a typical LMFBR. The replacement of fuel by the structural material of interest was such that in each case the value of k(infinity) was reduced to near-unity. This allowed the measurement of the lattice-k(infinity) by the null-reactivity technique. In addition, the principal reaction rates (namely U238 capture and fission, relative to Pu239 fission) and the neutron spectrum were measured. These directly measured integral data which are particularly sensitive to the steel cross-sections can be used for the checking and systematic adjustment of data sets. The results may also be analysed so as to derive specific values for the integral capture cross-sections of steel and iron. Neutron balance equations were set-up for each of the lattices using the measured k(infinity) and reaction rates
Study on keV-neutron capture cross sections and capture γ-ray spectra of 117,119Sn
Nishiyama, J.; Igashira, M.; Ohsaki, T.; Kim, G.N.; Chung, W.C.; Ro, T.I.
2006-01-01
The capture cross sections and capture γ-ray spectra of 117,119 Sn were measured in an incident neutron energy region from 10 to 100 keV and at 570 keV, using a 1.5-ns pulsed neutron source by the 7 Li(p,n) 7 Be reaction and a large anti-Compton NaI(Tl) γ-ray spectrometer. A pulse-height weighting technique was applied to observed capture γ-ray pulse-height spectra to derive capture yields. The capture cross sections of 117,119 Sn were obtained with the error of about 5% by using the standard capture cross sections of 197 Au. The present cross sections were compared with previous experimental data and the evaluated values in JENDL-3.3 and ENDF/B-VI. The capture γ-ray spectra of 117,119 Sn were derived by unfolding the observed capture γ-ray pulse-height spectra. The calculations of capture cross sections and capture γ-ray spectra of 117,119 Sn were performed with the EMPIRE-II code. The calculated results were compared with the present experimental ones. (author)
Effective cross section values for well-moderated thermal reactor spectra
Westcott, C.H
1970-11-15
This document replaces the earlier versions (CRRP-680 and CRRP-787) and now employs the {sigma} (E) information contained in Supplement 1 (1960) of the 2nd edition of BNL-325 and other data privately collected to a cut-off date of April 1, 1960. The compilation is also enlarged to include higher temperatures (thus superseding CRRP-862) and for the first time also includes s-factors calculated using the epithermal cut-off functions exhibiting a maximum at just above the cut-off energy, which have recently been indicated by Swedish and U.K. measurements, as well as by analysis of some calculated spectra. As in the earlier compilation, the notation of the author's Geneva Conference (1958) paper is used, the effective cross section {sigma} being given in terms of the 2200 m/sec. value {sigma}{sub o} by the relation {sigma} {sigma}{sub o} (g + rs), where g and s are the factors listed in this compilation and r is a measure of the proportion of epithermal neutrons in the reactor spectrum. (author)
Effective cross section values for well-moderated thermal reactor spectra
Westcott, C H
1970-11-15
This document replaces the earlier versions (CRRP-680 and CRRP-787) and now employs the {sigma} (E) information contained in Supplement 1 (1960) of the 2nd edition of BNL-325 and other data privately collected to a cut-off date of April 1, 1960. The compilation is also enlarged to include higher temperatures (thus superseding CRRP-862) and for the first time also includes s-factors calculated using the epithermal cut-off functions exhibiting a maximum at just above the cut-off energy, which have recently been indicated by Swedish and U.K. measurements, as well as by analysis of some calculated spectra. As in the earlier compilation, the notation of the author's Geneva Conference (1958) paper is used, the effective cross section {sigma} being given in terms of the 2200 m/sec. value {sigma}{sub o} by the relation {sigma} {sigma}{sub o} (g + rs), where g and s are the factors listed in this compilation and r is a measure of the proportion of epithermal neutrons in the reactor spectrum. (author)
Effective cross section values for well-moderated thermal reactor spectra
Westcott, C.H.
1970-11-01
This document replaces the earlier versions (CRRP-680 and CRRP-787) and now employs the σ (E) information contained in Supplement 1 (1960) of the 2nd edition of BNL-325 and other data privately collected to a cut-off date of April 1, 1960. The compilation is also enlarged to include higher temperatures (thus superseding CRRP-862) and for the first time also includes s-factors calculated using the epithermal cut-off functions exhibiting a maximum at just above the cut-off energy, which have recently been indicated by Swedish and U.K. measurements, as well as by analysis of some calculated spectra. As in the earlier compilation, the notation of the author's Geneva Conference (1958) paper is used, the effective cross section σ being given in terms of the 2200 m/sec. value σ o by the relation σ σ o (g + rs), where g and s are the factors listed in this compilation and r is a measure of the proportion of epithermal neutrons in the reactor spectrum. (author)
Evaluated cross section libraries
Maqurno, B.A.
1976-01-01
The dosimetry tape (ENDF/B-IV tape 412) was issued in a general CSEWG distribution, August 1974. The pointwise cross section data file was tested with specified reference spectra. A group averaged cross section data file (620 groups based on tape 412) was tested with the above spectra and the results are presented in this report
Calculational tools for the evaluation of nuclear cross-section and spectra data
Gardner, M.A.
1985-01-01
A technique based on discrete energy levels rather than energy level densities is presented for nuclear reaction calculations. The validity of the technique is demonstrated via theoretical and experimental agreement for cross sections, isomer-ratios and gamma-ray strength functions. 50 refs., 7 figs
Petriw, S; Cantargi, F; Granada, R
2006-01-01
We present here a Synthetic Model for Molecular Solids, aimed at the description of the interaction of thermal neutrons with this kind of systems.Simple representations of the molecular dynamical modes are used, in order to produce a fair description of neutron scattering kernels and cross sections with a minimum set of input data. Using those spectra, we have generated thermal libraries for M C N P [es
MC2-2: a code to calculate fast neutron spectra and multigroup cross sections
Henryson, H. II; Toppel, B.J.; Stenberg, C.G.
1976-06-01
MC 2 -2 is a program to solve the neutron slowing down problem using basic neutron data derived from the ENDF/B data files. The spectrum calculated by MC 2 -2 is used to collapse the basic data to multigroup cross sections for use in standard reactor neutronics codes. Four different slowing down formulations are used by MC 2 -2: multigroup, continuous slowing down using the Goertzel-Greuling or Improved Goertzel-Greuling moderating parameters, and a hyper-fine-group integral transport calculation. Resolved and unresolved resonance cross sections are calculated accounting for self-shielding, broadening and overlap effects. This document provides a description of the MC 2 -2 program. The physics and mathematics of the neutron slowing down problem are derived and detailed information is provided to aid the MC 2 -2 user in preparing input for the program and implementation of the program on IBM 370 or CDC 7600 computers
TEMPEST-2, Thermalization Program for Neutron Spectra and Multigroup Cross-Sections
Gowins, G.
1984-01-01
Description of problem or function: TEMPEST2 is a neutron thermalization program based upon the Wigner-Wilkins approximation for light moderators and the Wilkins approximation for heavy moderators. A Maxwellian distribution may also be used. The model used may be selected as a function of energy. The second-order differential equations are integrated directly rather than transformed to the Riccati equation. The program provides microscopic and macroscopic cross-section averages over the thermal neutron spectrum
Photoionization cross section by Stieltjes imaging applied to coupled cluster Lanczos pseudo-spectra
Cukras, Janusz; Coriani, Sonia; Decleva, Piero [Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Trieste, via L. Giorgieri 1, I-34127 Trieste (Italy); Christiansen, Ove [Department of Chemistry, Aarhus University, DK-8000 Aarhus C (Denmark); Norman, Patrick [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden)
2013-09-07
A recently implemented asymmetric Lanczos algorithm for computing (complex) linear response functions within the coupled cluster singles (CCS), coupled cluster singles and iterative approximate doubles (CC2), and coupled cluster singles and doubles (CCSD) is coupled to a Stieltjes imaging technique in order to describe the photoionization cross section of atoms and molecules, in the spirit of a similar procedure recently proposed by Averbukh and co-workers within the Algebraic Diagrammatic Construction approach. Pilot results are reported for the atoms He, Ne, and Ar and for the molecules H{sub 2}, H{sub 2}O, NH{sub 3}, HF, CO, and CO{sub 2}.
Photoionization cross section by Stieltjes imaging applied to coupled cluster Lanczos pseudo-spectra
Cukras, Janusz; Coriani, Sonia; Decleva, Piero; Christiansen, Ove; Norman, Patrick
2013-09-01
A recently implemented asymmetric Lanczos algorithm for computing (complex) linear response functions within the coupled cluster singles (CCS), coupled cluster singles and iterative approximate doubles (CC2), and coupled cluster singles and doubles (CCSD) is coupled to a Stieltjes imaging technique in order to describe the photoionization cross section of atoms and molecules, in the spirit of a similar procedure recently proposed by Averbukh and co-workers within the Algebraic Diagrammatic Construction approach. Pilot results are reported for the atoms He, Ne, and Ar and for the molecules H2, H2O, NH3, HF, CO, and CO2.
Photoionization cross section by Stieltjes imaging applied to coupled cluster Lanczos pseudo-spectra
Cukras, Janusz; Coriani, Sonia; Decleva, Piero; Christiansen, Ove; Norman, Patrick
2013-01-01
A recently implemented asymmetric Lanczos algorithm for computing (complex) linear response functions within the coupled cluster singles (CCS), coupled cluster singles and iterative approximate doubles (CC2), and coupled cluster singles and doubles (CCSD) is coupled to a Stieltjes imaging technique in order to describe the photoionization cross section of atoms and molecules, in the spirit of a similar procedure recently proposed by Averbukh and co-workers within the Algebraic Diagrammatic Construction approach. Pilot results are reported for the atoms He, Ne, and Ar and for the molecules H 2 , H 2 O, NH 3 , HF, CO, and CO 2
Measurements of Cross Sections and Charged Pion Spectra in Proton-Carbon Interactions at 31 GeV/c
Abgrall, N; Andrieu, B; Anticic, T; Antoniou, N; Argyriades, J; Asryan, A G; Baatar, B; Blondel, A; Blumer, J; Bogusz, M; Boldizsar, L; Bravar, A; Brooks, W; Brzychczyk, J; Bubak, A; Bunyatov, S A; Busygina, O; Cetner, T; Choi, K -U; Christakoglou, P; Chung, P; Czopowicz, T; Davis, N; Diakonos, F; Di Luise, S; Dominik, W; Dumarchez, J; Engel, R; Ereditato, A; Esposito, L S; Feofilov, G A; Fodor, Z; Ferrero, A; Fulop, A; Garrido, X; Gazdzicki, M; Golubeva, M; Grebieszkow, K; Grzeszczuk, A; Guber, F; Hakobyan, H; Hasegawa, T; Igolkin, S; Ivanov, A S; Ivanov, Y; Ivashkin, A; Kadija, K; Kapoyannis, A; Katrynska, N N; Kielczewska, D; Kikola, D; Kim, J -H; Kirejczyk, M; Kisiel, J; Kobayashi, T; Kochebina, O; Kolesnikov, V I; Kolev, D; Kondratiev, V P; Korzenev, A; Kowalski, S; Kuleshov, S; Kurepin, A; Lacey, R; Lagoda, J; Laszlo, A; Lyubushkin, V V; Mackowiak, M; Majka, Z; Malakhov, A I; Marchionni, A; Marcinek, A; Maris, I; Marin, V; Matulewicz, T; Matveev, V; Melkumov, G L; Meregaglia, A; Messina, M; Mrowczynski, St; Murphy, S; Nakadaira, T; Naumenko, P A; Nishikawa, K; Palczewski, T; Palla, G; Panagiotou, A D; Peryt, W; Petukhov, O; Planeta, R.; Pluta, J; Popov, B A; Posiadala, M; Pu lawski, S; Rauch, W; Ravonel, M; Renfordt, R; Robert, A; Rohrich, D; Rondio, E; Rossi, B; Roth, M; Rubbia, A; Rybczynski, M; Sadovsky, A; Sakashita, K; Sekiguchi, T; Seyboth, P; Shibata, M; Sissakian, A N; Skrzypczak, E; Slodkowski, M.; Sorin, A S; Staszel, P; Stefanek, G; Stepaniak, J; Strabel, C; Strobele, H; Susa, T; Szaik, P; Szuba, M; Tada, M; Taranenko, A; Tsenov, R; Ulrich, R; Unger, M; Vassiliou, M; Vechernin, V V; Vesztergombi, G; Wilczek, A; lodarczyk, Z W; Wojtaszek, A; Yi, J -G; Yoo, I -K; Zipper, W
2011-01-01
Interaction cross sections and charged pion spectra in p+C interactions at 31 GeV/c were measured with the large acceptance NA61/SHINE spectrometer at the CERN SPS. These data are required to improve predictions of the neutrino flux for the T2K long baseline neutrino oscillation experiment in Japan. A set of data collected during the first NA61/SHINE run in 2007 with an isotropic graphite target with a thickness of 4% of a nuclear interaction length was used for the analysis. The measured p+C inelastic and production cross sections are 257.2 +- 1.9 +- 8.9 mb and 229.3 +- 1.9 +- 9.0 mb, respectively. Inclusive production cross sections for negatively and positively charged pions are presented as a function of laboratory momentum in 10 intervals of the laboratory polar angle covering the range from 0 up to 420 mrad. The spectra are compared with predictions of several hadron production models.
Holmes, Jesse Curtis
Nuclear data libraries provide fundamental reaction information required by nuclear system simulation codes. The inclusion of data covariances in these libraries allows the user to assess uncertainties in system response parameters as a function of uncertainties in the nuclear data. Formats and procedures are currently established for representing covariances for various types of reaction data in ENDF libraries. This covariance data is typically generated utilizing experimental measurements and empirical models, consistent with the method of parent data production. However, ENDF File 7 thermal neutron scattering library data is, by convention, produced theoretically through fundamental scattering physics model calculations. Currently, there is no published covariance data for ENDF File 7 thermal libraries. Furthermore, no accepted methodology exists for quantifying or representing uncertainty information associated with this thermal library data. The quality of thermal neutron inelastic scattering cross section data can be of high importance in reactor analysis and criticality safety applications. These cross sections depend on the material's structure and dynamics. The double-differential scattering law, S(alpha, beta), tabulated in ENDF File 7 libraries contains this information. For crystalline solids, S(alpha, beta) is primarily a function of the material's phonon density of states (DOS). Published ENDF File 7 libraries are commonly produced by calculation and processing codes, such as the LEAPR module of NJOY, which utilize the phonon DOS as the fundamental input for inelastic scattering calculations to directly output an S(alpha, beta) matrix. To determine covariances for the S(alpha, beta) data generated by this process, information about uncertainties in the DOS is required. The phonon DOS may be viewed as a probability density function of atomic vibrational energy states that exist in a material. Probable variation in the shape of this spectrum may be
Production cross-sections for high mass particles and transverse momentum spectra
Arnold, R.C.; Halzen, F.
1977-06-01
The concept of transverse-mass (msub(T)) scaling is examined. It is suggested that: (1) experimental data on pion transverse momentum (psub(T)) spectra provide a reliable guide to expectations for high mass particle production; (2) dimensional scaling, e.g. implied by quark-gluon dynamics, yields an estimate of msub(T) -4 spectra at ultra-high energies; however, stronger damping is expected at currently accessible energies; (3) values increase linearly with the produced particle mass. The results of msub(T) scaling are compared with estimates for high mass production in the context of the Drell-Yan model. (author)
Mori, Takamasa
1985-05-01
In order to assess the cross section data for future reactor materials, such as molybdenum, niobium, titanium, lithium and fluorine, the angular neutron spectra in test piles of these materials or their chemical compounds have been measured in the energy range from a few keV to a few MeV by the linac time-of-flight method. The results have been compared with those theoretically calculated from the evaluated cross section data in such as JENDL-2 (or JENDL-1, JENDL-3PR1) and ENDF/B-IV. For both of molybdenum and niobium, it has been found that the energy distribution of inelastically scattered neutrons plays an important role in the analysis, and the JENDL library gives better predictions of spectrum shapes than ENDF/B-IV for both cases. In the case of niobium, however, it appears that the values of inelastic scattering cross section in JENDL-2 are too small around 2 MeV. It has been also found for niobium that the cross section data below 100 keV in ENDF/B-IV are inadequate. In a titanium pile, a discrepancy between the measured spectrum and the calculated one from ENDF/B-IV has been found in the energy range from about 60 keV to a few 100 keV. In order to investigate the cause of this discrepancy, the total cross sections for titanium have been measured by the transmission method. In the case of lithium, the discrepancy between the measured and calculated spectra is considerably reduced by adopting the angular distribution for 7 Li from ENDF/B-IV above about 500 keV. In the case of fluorine, spatial distributions of neutrons and X-rays have been also measured in both piles by the activation method to estimate the influence of photoneutrons generated in the sample material on the neutron distribution, and it has been found that their influence below 1 MeV is not so large as is necessary to be taken into account for the present assessment. (J.P.N)
Ter-Martirosyan, K.A.
1986-01-01
Experimental data of ISR and SPS colliders on σ tot and on the diffraction cone slope [B(s)] t=0 are used for a more precise determination of parameters (s=αp(0)-1 and others) of the supercritical Pomeron. With account of all P n rescatterings it leads to the Froissart type rise of cross sections at high energy. The quark-gluon string model of Pomeron, describing the existing experimental data, leads to predictions for super high energies of spectra of hadrons produced with small p perpendcular , in particular, the values of (dN ch /dy) y=0 , hadron average multiplicities =N-bar ch (ξ) and even their distributions over multiplicity W(N)=S N /σ in . The results are presented as curves and tables for energies √ s=0.9, 2, 4, 10, 20, 40, 10 2 , 10 3 TeV
MC2-2, Calculation of Fast Neutron Spectra and Multigroup Cross-Sections from ENDF/B Data
2001-01-01
1 - Description of program or function: MC 2 -2 solves the neutron slowing-down equations using basic neutron data derived from ENDF/B data files to determine fundamental mode spectra for use in generating multigroup neutron cross sections. The current edition includes the ability to treat all ENDF/B-V and -VI data representations. It accommodates high-order P scattering representations and provides numerous capabilities such as isotope mixing, delayed neutron processing, free-format input, and flexibility in output data selection. This edition supersedes previous releases of the MC22 program and the earlier MC2 program. Improved physics algorithms and increased computational efficiency are incorporated. Input data files required by MC2-2 may be generated from ENDF/B data by the code ETOE-2. The hyper-fine-group integral transport theory module of MC2-2, RABANL, is an improved version of the RABBLE/RABID codes. Many of the MC2-2 modules are used in the SDX code. 2 - Methods: The extended transport P1, B1, consistent P1, and consistent B1 fundamental mode ultra-fine-group equations are solved using continuous slowing-down theory and multigroup methods. Fast and accurate resonance integral methods are used in the narrow resonance resolved and unresolved resonance treatments. A fundamental mode homogeneous unit cell calculation is performed using either a multigroup or a continuous slowing-down treatment. Multigroup neutron homogeneous cross sections are generated in an ISOTXS format for an arbitrary group structure. A hyper-fine-group integral transport slowing down calculation (RABANL) is available as an option. RABANL performs a homogeneous or heterogeneous (pin or slab) unit cell calculation over the resonance region (resolved and unresolved) and generates multigroup neutron cross sections in an ISOTXS format. Neutron cross sections are generated by RABANL for the homogeneous unit cell and for each heterogeneous region in the pin or slab unit cell calculation
Budnar, M.; Cvelbar, F.; Likar, A.; Martincic, R.; Potokar, M.; Ivkovic, V.
1977-01-01
Gamma ray spectra and integrated cross sections for radiative capture in 45 Sc, 89 Y, 141 Pr and 165 Ho have been measured. Obtained integrated cross sections (800+-110)μb, (1490+-210)μb, (980+-160)μb and (940+-150)μb are in accordance with measurements at other elements showing smooth mass dependence. Measuring procedure and experimental data evaluation is described in details. (author)
Iwamoto, Yosuke, E-mail: iwamoto.yosuke@jaea.go.jp; Ogawa, Tatsuhiko
2017-04-01
Because primary knock-on atoms (PKAs) create point defects and clusters in materials that are irradiated with neutrons, it is important to validate the calculations of recoil cross section spectra that are used to estimate radiation damage in materials. Here, the recoil cross section spectra of fission- and fusion-relevant materials were calculated using the Event Generator Mode (EGM) of the Particle and Heavy Ion Transport code System (PHITS) and also using the data processing code NJOY2012 with the nuclear data libraries TENDL2015, ENDF/BVII.1, and JEFF3.2. The heating number, which is the integral of the recoil cross section spectra, was also calculated using PHITS-EGM and compared with data extracted from the ACE files of TENDL2015, ENDF/BVII.1, and JENDL4.0. In general, only a small difference was found between the PKA spectra of PHITS + TENDL2015 and NJOY + TENDL2015. From analyzing the recoil cross section spectra extracted from the nuclear data libraries using NJOY2012, we found that the recoil cross section spectra were incorrect for {sup 72}Ge, {sup 75}As, {sup 89}Y, and {sup 109}Ag in the ENDF/B-VII.1 library, and for {sup 90}Zr and {sup 55}Mn in the JEFF3.2 library. From analyzing the heating number, we found that the data extracted from the ACE file of TENDL2015 for all nuclides were problematic in the neutron capture region because of incorrect data regarding the emitted gamma energy. However, PHITS + TENDL2015 can calculate PKA spectra and heating numbers correctly.
2015-11-24
Raman spectra and cross sections of ammonia, chlorine, hydrogen sulfide, phosgene, and sulfur dioxide toxic gases in the fingerprint region 400...1400 cm‐1 R. L. Aggarwal, L. W. Farrar, S. Di Cecca, and T. H. Jeys MIT Lincoln Laboratory, Lexington, MA 02420‐9108 Raman spectra of...region 400‐1400 cm‐1. A relatively compact (< 2’x2’x2’), sensitive, 532 nm 10 W CW Raman system with double‐pass
2015-12-14
Raman spectra and cross sections of ammonia, chlorine, hydrogen sulfide, phosgene, and sulfur dioxide toxic gases in the fingerprint region 400...1400 cm‐1 R. L. Aggarwal, L. W. Farrar, S. Di Cecca, and T. H. Jeys MIT Lincoln Laboratory, Lexington, MA 02420‐9108 Raman spectra of...region 400‐1400 cm‐1. A relatively compact (< 2’x2’x2’), sensitive, 532 nm 10 W CW Raman system with double‐pass
Ullmann, John Leonard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kawano, Toshihiko [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bredeweg, Todd Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Baramsai, Bayarbadrakh [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Couture, Aaron Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Haight, Robert Cameron [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jandel, Marian [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mosby, Shea Morgan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); O' Donnell, John M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rundberg, Robert S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Vieira, David J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wilhelmy, Jerry B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Becker, John A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wu, Ching-Yen [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Krticka, Milan [Charles Univ., Prague (Czech Republic)
2015-05-28
Neutron capture cross sections in the “continuum” region (>≈1 keV) and gamma-emission spectra are of importance to basic science and many applied fields. Careful measurements have been made on most common stable nuclides, but physicists must rely on calculations (or “surrogate” reactions) for rare or unstable nuclides. Calculations must be benchmarked against measurements (cross sections, gamma-ray spectra, and <Γ_{γ}>). Gamma-ray spectrum measurements from resolved resonances were made with 1 - 2 mg/cm^{2} thick targets; cross sections at >1 keV were measured using thicker targets. The results show that the shape of capture cross section vs neutron energy is not sensitive to the form of the strength function (although the magnitude is); the generalized Lorentzian E1 strength function is not sufficient to describe the shape of observed gamma-ray spectra; MGLO + “Oslo M1” parameters produces quantitative agreement with the measured ^{238}U(n,γ) cross section; additional strength at low energies (~ 3 MeV) -- likely M1-- is required; and careful study of complementary results on low-lying giant resonance strength is needed to consistently describe observations.
Tassan, S.
1978-01-01
A selection of technical documents is given concerning the experimental determination of the neutron capture cross-sections of fast reactor structural materials (Fe, Cr, Ni...) integrated over the intermediate energy spectra. The experimental structure project and modifications of the reactor RB2 for this experiment, together with criticality and safety calculations, are presented
Campbell, L.; Brunger, M.J.; Teubner, O.J.P.; Mojarrabi, B.
1996-06-01
A set of three computer programs is reported which allow for the deconvolution of overlapping molecular electronic state structure in electron energy-loss spectra, even in highly perturbed systems. This procedure enables extraction of absolute differential cross sections for electron-impact excitation of electronic states of diatomic molecules from electron energy-loss spectra. The first code in the sequence uses the Rydberg-Klein-Rees procedure to generate potential energy curves from spectroscopic constants, while the second calculates Franck-Condon factors by numerical solution of the Schroedinger equation, given the potential energy curves. The third, given these Franck-Condon factors, the previously calculated relevant energies for the vibrational levels of the respective electronic states and the experimental energy-loss spectra, extracts the differential cross sections for each state. Each program can be run independently, or the three can run in sequence to determine these cross sections from the spectroscopic constants and the experimental energy-loss spectra. The application of these programs to the specific case of electron scattering from nitric oxide (NO) is demonstrated. 25 refs., 2 tabs., 2 figs
Inclusive proton spectra and total reaction cross sections for proton-nucleus scattering at 800 MeV
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
Simakov, S.P.; Konobeyev, A.Yu.; Koning, A.
2016-01-01
The goal of this work is a calculation of the covariance matrices for the physical quantities used to characterize the neutron induced radiation damage in the materials. Such quantities usually encompass: the charged particles kinetic energy deposition KERMA (locally deposited nuclear heating), damage energy (to calculate then the number of displaced atoms) and gas production cross sections [(n,xα), (n,xt), (n,xp) … to calculate then transmuting of target nuclei to gases]. The uncertainties and energy-energy or reaction-reaction correlations for such quantities were not assessed so far, whereas the covariances for many underlying cross sections are often presented in the evaluated data libraries. Due to the dependence of damage quantities on many reactions channels, on both total and differential cross sections, and in particular on the energy distribution of reaction recoils, the evaluation of uncertainty is not straightforward. To reach a goal, we used the method based on idea of Total Monte Carlo application to the Nuclear Data. This report summarises the current results for evaluation, validation and representation in the ENDF-6 format of the radiation damage covariances for n + 56 Fe from thermal energy up to 20 MeV. This study was motivated by the IAEA Coordinated Research Project ''Primary Radiation Damage Cross Sections'' and by present dedicated Technical Meeting “Nuclear Reaction Data and Uncertainties for Radiation Damage”
Young, P.G.; Arthur, E.D.
1977-11-01
A new multistep Hauser--Feshbach code that includes corrections for preequilibrium effects is described. The code can calculate up to 60 decay reactions (cross sections and energy spectra) in one computation, and thereby provide considerable flexibility for handling processes with complicated reaction chains. Input parameter setup, problem output, and subroutine descriptions are given along with a sample problem calculation. A brief theoretical description is also included. 8 figures, 3 tables.
Moro, M. V.; Bruckner, B.; Grande, P. L.; Tabacniks, M. H.; Bauer, P.; Primetzhofer, D.
2018-06-01
We have experimentally determined electronic stopping cross sections of vanadium for 50-2750 keV protons and for 250-6000 keV He ions by relative measurements in backscattering geometry. To check the consistency of the employed procedure we investigate how to define adequate reference stopping cross section data and chose different reference materials. To proof consistency of different reference data sets, an intercomparison is performed to test the reliability of the evaluation procedure for a wide range of energies. This process yielded consistent results. The resulting stopping cross section data for V are compared to values from the IAEA database, to the most commonly employed semi-empirical program SRIM, and to calculations according to CasP. For helium, our results show a significant deviation of up to 10% with respect to literature and to SRIM, but are in very good agreement with the CasP predictions, in particular when charge-exchange processes are included in the model.
Cross sections and differential spectra for reactions of 2-20 MeV neutrons on /sup nat/Cr
Blann, M.; Komoto, T.T.
1988-01-01
This report summarizes product yields, secondary n,p and α spectra, and γ-ray spectra calculated for incident neutrons of 2 to 20 MeV on /sup nat/Cr targets. Results are all from the code ALICE, using the version ALISO which does weighting of results for targets which are a mix of isotopes. Where natural isotopic targets are involved, yields and n,p,α spectra will be reported weighted over isotopic yields. Gamma-ray spectra, however, will be reported for the most abundant isotope. We present product yields versus incident neutron energy, n,p,α spectra versus incident neutron energy, and calculated γ-ray spectra
Minnesota Department of Natural Resources — FEMA Cross Sections are required for any Digital Flood Insurance Rate Map database where cross sections are shown on the Flood Insurance Rate Map (FIRM). Normally...
Zawadzka-Kazimierczuk, Anna; Kozminski, Wiktor [University of Warsaw, Faculty of Chemistry (Poland); Billeter, Martin, E-mail: martin.billeter@chem.gu.se [University of Gothenburg, Biophysics Group, Department of Chemistry and Molecular Biology (Sweden)
2012-09-15
While NMR studies of proteins typically aim at structure, dynamics or interactions, resonance assignments represent in almost all cases the initial step of the analysis. With increasing complexity of the NMR spectra, for example due to decreasing extent of ordered structure, this task often becomes both difficult and time-consuming, and the recording of high-dimensional data with high-resolution may be essential. Random sampling of the evolution time space, combined with sparse multidimensional Fourier transform (SMFT), allows for efficient recording of very high dimensional spectra ({>=}4 dimensions) while maintaining high resolution. However, the nature of this data demands for automation of the assignment process. Here we present the program TSAR (Tool for SMFT-based Assignment of Resonances), which exploits all advantages of SMFT input. Moreover, its flexibility allows to process data from any type of experiments that provide sequential connectivities. The algorithm was tested on several protein samples, including a disordered 81-residue fragment of the {delta} subunit of RNA polymerase from Bacillus subtilis containing various repetitive sequences. For our test examples, TSAR achieves a high percentage of assigned residues without any erroneous assignments.
Blann, M.
1985-08-01
The Boltzmann master equation model has been applied to the question of precompound nucleon de-excitation of reactions induced by 10 to 100 MeV/nucleon (c.m.) heavy ions. Test systems of 16 O + 60 Ni and 27 Al + 86 Kr were selected. Experimental neutron spectra in coincidence with evaporation residue and fission fragments from the 20 Ne + 165 Ho system (due to Holub, et al.) were reproduced quite well by the master equation with exciton numbers between 20 and 23. Results show major fractions of the excitation and up to 35 nucleons removed during the coalescence-equilibration period. The linear momentum transfer predicted by the master equation is shown to be in good agreement with a broad range of data. Extension of the master equation to predict sub-threshold PI 0 production cross sections is shown to give satisfactory agreement with a large number of experimental results. 48 refs., 8 figs., 7 tabs
Baba, Mamoru; Itoh, Nobuo; Maeda, Kazuto; Hirakawa, Naohiro; Wakabayashi, Hidetaka.
1989-10-01
This report presents the summary of experimental studies of prompt fission neutron spectra and double-differential neutron inelastic-scattering cross sections of 238 U and 232 Th. The experiments were performed at Tohoku University Fast Neutron Laboratory employing a time-of-flight technique and Dynamitron accelerator as the pulsed neutron generator. From the experiments, we obtained the following data for both nuclei; 1. prompt fission neutron spectrum for 2 MeV neutrons, 2. double-differential neutron inelastic-scattering cross sections for 1.2, 2.0, 4.2, 6.1 and 14.1 MeV incident neutrons. Both in experiments and data processing, cares were taken to obtain reliable data by avoiding systematic uncertainty. The experimental data were compared with those by other experiments, evaluations and model calculations. Through the data comparison, some fundamental problems were found in the experiments by previous authors and the evaluations. The present data will provide useful data base for refinement of the evaluated data and theoretical models. (author)
Chou Chau, Yuan-Fong; Lim, Chee Ming; Kumara, N. T. R. N.; Yoong, Voo Nyuk; Lee, Chuanyo; Huang, Hung Ji; Lin, Chun-Ting; Chiang, Hai-Pang
2016-01-01
Tunable surface plasmon resonance (SPR) and dipole cavity plasmon modes of the scattering cross section (SCS) spectra on the single solid-gold/gold-shell nanorod have been numerically investigated by using the finite element method. Various effects, such as the influence of SCS spectra under x- and y-polarizations on the surface of the single solid-gold/gold-shell nanorod, are discussed in detail. With the single gold-shell nanorod, one can independently tune the relative SCS spectrum width by controlling the rod length and rod diameter, and the surface scattering by varying the shell thickness and polarization direction, as well as the dipole peak energy. These behaviors are consistent with the properties of localized SPRs and offer a way to optically control and produce selected emission wavelengths from the single solid-gold/gold-shell nanorod. The electric field and magnetic distributions provide us a qualitative idea of the geometrical properties of the single solid-gold/gold-shell nanorod on plasmon resonance.
Photon-splitting cross sections
Johannessen, A.M.; Mork, K.J.; Overbo, I.
1980-01-01
The differential cross section for photon splitting (scattering of one photon into two photons) in a Coulomb field, obtained earlier by Shima, has been integrated numerically to yield various differential cross sections. Energy spectra differential with respect to the energy of one of the outgoing photons are presented for several values of the primary photon energy. Selected examples of recoil momentum distributions and some interesting doubly or multiply differential cross sections are also given. Values for the total cross section are obtained essentially for all energies. The screening effect caused by atomic electrons is also taken into account, and is found to be important for high energies, as in e + e - pair production. Comparisons with various approximate results obtained by previous authors mostly show fair agreement. We also discuss the possibilities for experimental detection and find the most promising candidate to be a measurement of both photons, and their energies, at a moderately high energy
Nuclear Forensics and Radiochemistry: Cross Sections
Rundberg, Robert S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-11-08
The neutron activation of components in a nuclear device can provide useful signatures of weapon design or sophistication. This lecture will cover some of the basics of neutron reaction cross sections. Nuclear reactor cross sections will also be presented to illustrate the complexity of convolving neutron energy spectra with nuclear excitation functions to calculate useful effective reactor cross sections. Deficiencies in the nuclear database will be discussed along with tools available at Los Alamos to provide new neutron cross section data.
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
Floodplain Cross Section Lines
Department of Homeland Security — This table is required for any Digital Flood Insurance Rate Map database where cross sections are shown on the Flood Insurance Rate Map (FIRM). Normally any FIRM...
Multitrajectory eikonal cross sections
Turner, R.E.
1983-01-01
With the use of reference and distorted transition operators, a time-correlation-function representation of the inelastic differential cross section has recently been used to obtain distorted eikonal cross sections. These cross sections involve straight-line and reference classical translational trajectories that are unaffected by any internal-state changes which have occurred during the collision. This distorted eikonal theory is now extended to include effects of internal-state changes on the translational motion. In particular, a different classical trajectory is associated with each pair of internal states. Expressions for these inelastic cross sections are obtained in terms of time-ordered cosine and sine memory functions using the Zwanzig-Feshbach projection-operator method. Explicit formulas are obtained in the time-disordered perturbation approximation
R. L. Aggarwal
2016-02-01
Full Text Available Raman spectra of ammonia (NH3, chlorine (Cl2, hydrogen sulfide (H2S, phosgene (COCl2, and sulfur dioxide (SO2 toxic gases have been measured in the fingerprint region 400-1400 cm−1. A relatively compact (<2′x2′x2′, sensitive, 532 nm 10 W CW Raman system with double-pass laser and double-sided collection was used for these measurements. Two Raman modes are observed at 934 and 967 cm−1 in NH3. Three Raman modes are observed in Cl2 at 554, 547, and 539 cm−1, which are due to the 35/35 35/37, and 37/37 Cl isotopes, respectively. Raman modes are observed at 870, 570, and 1151 cm−1 in H2S, COCl2, and SO2, respectively. Values of 3.68 ± 0.26x10−32 cm2/sr (3.68 ± 0.26x10−36 m2/sr, 1.37 ± 0.10x10−30 cm2/sr (1.37 ± 0.10x10−34 m2/sr, 3.25 ± 0.23x10−31 cm2/sr (3.25 ± 0.23x10−35 m2/sr, 1.63 ± 0.14x10−30 cm2/sr (1.63 ± 0.14x10−34 m2/sr, and 3.08 ± 0.22x10−30 cm2/sr (and 3.08 ± 0.22x10−34 m2/sr were determined for the differential Raman cross section of the 967 cm−1 mode of NH3, sum of the 554, 547, and 539 cm−1 modes of Cl2, 870 cm−1 mode of H2S, 570 cm−1 mode of COCl2, and 1151 cm-1 mode of SO2, respectively, using the differential Raman cross section of 3.56 ± 0.14x10−31 cm2/sr (3.56 ± 0.14x10−35 m2/sr for the 1285 cm−1 mode of CO2 as the reference.
Laville, J.-L.
1976-01-01
The creation of a high intensity beam of monokinetic neutrons obtained from stripping deuterons extracted from the synchrotron Saturne (C.E.N., Saclay) has allowed to measure with good statistical accuracy 43 momentum spectra of the final proton of the inclusive reaction np→pX at 1.39, 1.56, 1.73 and 1.90GeV/c (approximately 10 spectra per incident momentum). The final proton was analyzed with a magnetic spectrometer in the angular region between 0 and 20 deg in the laboratory. The set of results has been the object of two analyses: at first, the experimental spectra were compared with a pion exchange model modified by the off-shell parametrization of BENECKE-DURR-PILKUHN overall, this model correctly reproduces the measured spectra, both in form and absolute normalization. In the second analysis, the total and differential cross sections of the np→pΔ 33 0 channel were determined from the spectra measured using a subtraction procedure. The differential cross sections obtained in this way show an angular dependence that differs from the predictions of the pion exchange model. It is concluded that, at low energy, near its threshold, the reaction NN→NΔ 33 involves a set of more complex mechanisms than pion exchange alone, even if the latter remains dominant [fr
Youinou, Gilles Jean-Michel [Idaho National Lab. (INL), Idaho Falls, ID (United States)
2015-10-01
Neutron cross-sections characterize the way neutrons interact with matter. They are essential to most nuclear engineering projects and, even though theoretical progress has been made as far as the predictability of neutron cross-section models, measurements are still indispensable to meet tight design requirements for reduced uncertainties. Within the field of fission reactor technology, one can identify the following specializations that rely on the availability of accurate neutron cross-sections: (1) fission reactor design, (2) nuclear fuel cycles, (3) nuclear safety, (4) nuclear safeguards, (5) reactor monitoring and neutron fluence determination and (6) waste disposal and transmutation. In particular, the assessment of advanced fuel cycles requires an extensive knowledge of transuranics cross sections. Plutonium isotopes, but also americium, curium and up to californium isotope data are required with a small uncertainty in order to optimize significant features of the fuel cycle that have an impact on feasibility studies (e.g. neutron doses at fuel fabrication, decay heat in a repository, etc.). Different techniques are available to determine neutron cross sections experimentally, with the common denominator that a source of neutrons is necessary. It can either come from an accelerator that produces neutrons as a result of interactions between charged particles and a target, or it can come from a nuclear reactor. When the measurements are performed with an accelerator, they are referred to as differential since the analysis of the data provides the cross-sections for different discrete energies, i.e. σ(E_{i}), and for the diffusion cross sections for different discrete angles. Another approach is to irradiate a very pure sample in a test reactor such as the Advanced Test Reactor (ATR) at INL and, after a given time, determine the amount of the different transmutation products. The precise characterization of the nuclide densities before and after
2000-10-01
This document provides users of photonuclear data with an up-to-date overview of photonuclear reaction data. In addition to production cross sections, energy and angular distributions of the emitted particles are provided. The material is presented in a systematic way, covering experimental data and their compilation, an introduction to relevant parts of nuclear reaction theory, an exposition of evaluation methodology used to generate evaluations, an intercomparison of different evaluations, and a description of the IAEA Photonuclear Data Library
Knott, Gene; Tuley, Michael
2004-01-01
This is the second edition of the first and foremost book on this subject for self-study, training, and course work. Radar cross section (RCS) is a comparison of two radar signal strengths. One is the strength of the radar beam sweeping over a target, the other is the strength of the reflected echo sensed by the receiver. This book shows how the RCS ?gauge? can be predicted for theoretical objects and how it can be measured for real targets. Predicting RCS is not easy, even for simple objects like spheres or cylinders, but this book explains the two ?exact? forms of theory so well that even a
Photoproton cross section for /sup 19/F
Tsubota, H [Tohoku Univ., Sendai (Japan). Coll. of General Education; Kawamura, N; Oikawa, S; Uegaki, J I
1975-02-01
Proton energy spectra have been measured at 90/sup 0/ for the /sup 19/F(e,e'p)/sup 18/O reaction in the giant resonance region. The (..gamma..,p/sub 0/) and (..gamma..,p/sub 1/) differential cross sections are extracted from the proton energy spectra by using virtual-photon spectra. The integrated differential cross section of the (..gamma..,p/sub 0/) and (..gamma..,p/sub 1/) reactions are 1.80+-0.27 and 0.50+-0.45 MeV-mb/sr, respectively. The results are discussed with the shell model theory by comparing with the (..gamma..,p/sub 0/) cross section of the neighboring 4n-nucleus /sup 20/Ne. A significant increase of the proton yield leaving the non-ground states is found at 25 MeV of the incident electron energy. This is discussed in terms of the core excitation effect.
Recommended evaluation procedure for photonuclear cross section
Lee, Young-Ouk; Chang, Jonghwa; Fukahori, Tokio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
1998-03-01
In order to generate photonuclear cross section library for the necessary applications, data evaluation is combined with theoretical evaluation, since photonuclear cross sections measured cannot provide all necessary data. This report recommends a procedure consisting of four steps: (1) analysis of experimental data, (2) data evaluation, (3) theoretical evaluation and, if necessary, (4) modification of results. In the stage of analysis, data obtained by different measurements are reprocessed through the analysis of their discrepancies to a representative data set. In the data evaluation, photonuclear absorption cross sections are evaluated via giant dipole resonance and quasi-deutron mechanism. With photoabsorption cross sections from the data evaluation, theoretical evaluation is applied to determine various decay channel cross sections and emission spectra using equilibrium and preequilibrium mechanism. After this, the calculated results are compared with measured data, and in some cases the results are modified to better describe measurements. (author)
Carlson, A.D.
1984-01-01
The accuracy of neutron cross-section measurement is limited by the uncertainty in the standard cross-section and the errors associated with using it. Any improvement in the standard immediately improves all cross-section measurements which have been made relative to that standard. Light element, capture and fission standards are discussed. (U.K.)
Cross sections for atmospheric corrections
Meyer, J.P.; Casse, M.; Westergaard, N.
1975-01-01
A set of cross sections for spallation of relativistic nuclei is proposed based on (i) the best available proton cross sections, (ii) an extrapolation to heavier nuclei of the dependence on the number of nucleons lost of the 'target factor' observed for C 12 and O 16 by Lindstrom et al. (1975), in analogy with Rudstam's formalism, and (iii) on a normalization of all cross sections to the total cross sections for production of fragments with Asub(f) >= 6. The obtained cross sections for peripheral interactions are not inconsistent with simple geometrical considerations. (orig.) [de
McCracken, A.K.; Packwood, A.
1978-01-01
Neutron spectroscopy in a favourable environment can yield without supporting calculations a wealth of spectral detail which cannot be approached by the multiple foil analysis (MFA) method. On the other hand in hostile environments only MFA methods are available and they require validation and/or improvement by exposing them to comparison with other types of measurement and definitive calculation in tightly controlled test neutron spectra. This paper considers some problems related to MFA unfolding of flux spectra, systematic and random errors in detector measurements and the choice of detectors which will be of maximum use in all environments of current interest
NDS multigroup cross section libraries
DayDay, N.
1981-12-01
A summary description and documentation of the multigroup cross section libraries which exist at the IAEA Nuclear Data Section are given in this report. The libraries listed are available either on tape or in printed form. (author)
XCOM: Photon Cross Sections Database
SRD 8 XCOM: Photon Cross Sections Database (Web, free access) A web database is provided which can be used to calculate photon cross sections for scattering, photoelectric absorption and pair production, as well as total attenuation coefficients, for any element, compound or mixture (Z <= 100) at energies from 1 keV to 100 GeV.
Doppler broadening of cross sections
Buckler, P.A.C.; Pull, I.C.
1962-12-01
Expressions for temperature dependent cross-sections in terms of resonance parameters are obtained, involving generalisations of the conventional Doppler functions, ψ and φ. Descriptions of Fortran sub-routines, which calculate broadened cross-sections in accordance with the derived formulae, are included. (author)
Wilhelmi, O.; Schartner, K.H.
2000-01-01
For pt.II see ibid., vol.11, p.45-58, 2000. Molecular oxygen O 2 was dissociated in collisions with protons and electrons in the intermediate velocity range (p + -energies: 17-800 keV, e - -energies: 0.2-2 keV). Fluorescence from excited atomic and singly ionised fragments and from singly ionised molecules was detected in the VUV and in the visible and near UV spectral range. Highly resolved spectra are presented for the VUV (46-131 nm) and the near UV/visible (340-605 nm) spectral range. Absolute emission cross-sections have been determined for dissociative ionisation and excitation leading to fluorescence in the VUV. Results are compared with published data. (orig.)
Neutron Cross Sections for Aluminium
Forsberg, Leif
1963-08-15
Total, elastic, inelastic, (n, 2n), (n, {alpha}), (n, p), and (n, {gamma}) cross sections for aluminium have been compiled from thermal to 100 MeV based upon literature search and theoretical interpolations and estimates. Differential elastic cross sections in the centre of mass system are represented by the Legendre coefficients. This method was chosen in order to obtain the best description of the energy dependence of the anisotropy.
Accurate Cross Sections for Microanalysis
Rez, Peter
2002-01-01
To calculate the intensity of x-ray emission in electron beam microanalysis requires a knowledge of the energy distribution of the electrons in the solid, the energy variation of the ionization cross section of the relevant subshell, the fraction of ionizations events producing x rays of interest and the absorption coefficient of the x rays on the path to the detector. The theoretical predictions and experimental data available for ionization cross sections are limited mainly to K shells of a...
Low Energy Neutrino Cross Sections
Zeller, G.P.
2004-01-01
Present atmospheric and accelerator based neutrino oscillation experiments operate at low neutrino energies (Ev ∼ 1 GeV) to access the relevant regions of oscillation parameter space. As such, they require precise knowledge of the cross sections for neutrino-nucleon interactions in the sub-to-few GeV range. At these energies, neutrinos predominantly interact via quasi-elastic (QE) or single pion production processes, which historically have not been as well studied as the deep inelastic scattering reactions that dominate at higher energies.Data on low energy neutrino cross sections come mainly from bubble chamber, spark chamber, and emulsion experiments that collected their data decades ago. Despite relatively poor statistics and large neutrino flux uncertainties, these measurements provide an important and necessary constraint on Monte Carlo models in present use. The following sections discuss the current status of QE, resonant single pion, coherent pion, and single kaon production cross section measurements at low energy
A Pebble Bed Reactor cross section methodology
Hudson, Nathanael H.; Ougouag, Abderrafi M.; Rahnema, Farzad; Gougar, Hans
2009-01-01
A method is presented for the evaluation of microscopic cross sections for the Pebble Bed Reactor (PBR) neutron diffusion computational models during convergence to an equilibrium (asymptotic) fuel cycle. This method considers the isotopics within a core spectral zone and the leakages from such a zone as they arise during reactor operation. The randomness of the spatial distribution of fuel grains within the fuel pebbles and that of the fuel and moderator pebbles within the core, the double heterogeneity of the fuel, and the indeterminate burnup of the spectral zones all pose a unique challenge for the computation of the local microscopic cross sections. As prior knowledge of the equilibrium composition and leakage is not available, it is necessary to repeatedly re-compute the group constants with updated zone information. A method is presented to account for local spectral zone composition and leakage effects without resorting to frequent spectrum code calls. Fine group data are pre-computed for a range of isotopic states. Microscopic cross sections and zone nuclide number densities are used to construct fine group macroscopic cross sections, which, together with fission spectra, flux modulation factors, and zone buckling, are used in the solution of the slowing down balance to generate a new or updated spectrum. The microscopic cross-sections are then re-collapsed with the new spectrum for the local spectral zone. This technique is named the Spectral History Correction (SHC) method. It is found that this method accurately recalculates local broad group microscopic cross sections. Significant improvement in the core eigenvalue, flux, and power peaking factor is observed when the local cross sections are corrected for the effects of the spectral zone composition and leakage in two-dimensional PBR test problems.
Discussion of electron cross sections for transport calculations
Berger, M.J.
1983-01-01
This paper deals with selected aspects of the cross sections needed as input for transport calculations and for the modeling of radiation effects in biological materials. Attention is centered mainly on the cross sections for inelastic interactions between electrons and water molecules and the use of these cross sections for the calculation of energy degradation spectra and of ionization and excitation yields. 40 references, 3 figures, 1 table
Terahertz radar cross section measurements
Iwaszczuk, Krzysztof; Heiselberg, Henning; Jepsen, Peter Uhd
2010-01-01
We perform angle- and frequency-resolved radar cross section (RCS) measurements on objects at terahertz frequencies. Our RCS measurements are performed on a scale model aircraft of size 5-10 cm in polar and azimuthal configurations, and correspond closely to RCS measurements with conventional radar...
Barashenkov, V.S.
1990-01-01
The tables of inelastic and total cross sections of π ± mesons interactions with nuclei 4 He- 238 U are presented. The tables are obtained by theoretical analysis of known experimental data for energies higher some tens of MeV. 1 ref.; 1 tab
Cross sections required for FMIT dosimetry
Gold, R.; McElroy, W.N.; Lippincott, E.P.; Mann, F.M.; Oberg, D.L.; Roberts, J.H.; Ruddy, F.H.
1980-01-01
The Fusion Materials Irradiation Test (FMIT) facility, currently under construction, is designed to produce a high flux of high energy neutrons for irradiation effects experiments on fusion reactor materials. Characterization of the flux-fluence-spectrum in this rapidly varying neutron field requires adaptation and extension of currently available dosimetry techniques. This characterization will be carried out by a combination of active, passive, and calculational dosimetry. The goal is to provide the experimenter with accurate neutron flux-fluence-spectra at all positions in the test cell. Plans have been completed for a number of experimental dosimetry stations and provision for these facilities has been incorporated into the FMIT design. Overall needs of the FMIT irradiation damage program delineate goal accuracies for dosimetry that, in turn, create new requirements for high energy neutron cross section data. Recommendations based on these needs have been derived for required cross section data and accuracies
Neutron cross sections for fusion
Haight, R.C.
1979-10-01
First generation fusion reactors will most likely be based on the 3 H(d,n) 4 He reaction, which produces 14-MeV neutrons. In these reactors, both the number of neutrons and the average neutron energy will be significantly higher than for fission reactors of the same power. Accurate neutron cross section data are therefore of great importance. They are needed in present conceptual designs to calculate neutron transport, energy deposition, nuclear transmutation including tritium breeding and activation, and radiation damage. They are also needed for the interpretation of radiation damage experiments, some of which use neutrons up to 40 MeV. In addition, certain diagnostic measurements of plasma experiments require nuclear cross sections. The quality of currently available data for these applications will be reviewed and current experimental programs will be outlined. The utility of nuclear models to provide these data also will be discussed. 65 references
Negative ion detachment cross sections
Champion, R.L.; Doverspike, L.D.
1992-10-01
The authors have measured absolute cross sections for electron detachment and charge exchange for collision of O and S with atomic hydrogen, have investigated the sputtering and photodesorption of negative ions from gas covered surfaces, and have begun an investigation of photon-induced field emission of electrons from exotic structures. Brief descriptions of these activities as well as future plans for these projects are given below
Microscopic cross sections: An utopia?
Hilaire, S. [CEA Bruyeres-le-Chatel, DIF 91 (France); Koning, A.J. [Nuclear Research and Consultancy Group, PO Box 25, 1755 ZG Petten (Netherlands); Goriely, S. [Institut d' Astronomie et d' Astrophysique, Universite Libre de Bruxelles, Campus de la Plaine, CP 226, 1050 Brussels (Belgium)
2010-07-01
The increasing need for cross sections far from the valley of stability poses a challenge for nuclear reaction models. So far, predictions of cross sections have relied on more or less phenomenological approaches, depending on parameters adjusted to available experimental data or deduced from systematical relations. While such predictions are expected to be reliable for nuclei not too far from the experimentally known regions, it is clearly preferable to use more fundamental approaches, based on sound physical bases, when dealing with very exotic nuclei. Thanks to the high computer power available today, all major ingredients required to model a nuclear reaction can now be (and have been) microscopically (or semi-microscopically) determined starting from the information provided by a nucleon-nucleon effective interaction. We have implemented all these microscopic ingredients in the TALYS nuclear reaction code, and we are now almost able to perform fully microscopic cross section calculations. The quality of these ingredients and the impact of using them instead of the usually adopted phenomenological parameters will be discussed. (authors)
Microscopic cross sections: An utopia?
Hilaire, S.; Koning, A.J.; Goriely, S.
2010-01-01
The increasing need for cross sections far from the valley of stability poses a challenge for nuclear reaction models. So far, predictions of cross sections have relied on more or less phenomenological approaches, depending on parameters adjusted to available experimental data or deduced from systematical relations.While such predictions are expected to be reliable for nuclei not too far from the experimentally known regions, it is clearly preferable to use more fundamental approaches, based on sound physical bases, when dealing with very exotic nuclei. Thanks to the high computer power available today, all major ingredients required to model a nuclear reaction can now be (and have been) microscopically (or semi-microscopically) determined starting from the information provided by a nucleon-nucleon effective interaction. We have implemented all these microscopic ingredients in the TALYS nuclear reaction code, and we are now almost able to perform fully microscopic cross section calculations. The quality of these ingredients and the impact of using them instead of the usually adopted phenomenological parameters will be discussed. (authors)
Wind Turbine Radar Cross Section
David Jenn
2012-01-01
Full Text Available The radar cross section (RCS of a wind turbine is a figure of merit for assessing its effect on the performance of electronic systems. In this paper, the fundamental equations for estimating the wind turbine clutter signal in radar and communication systems are presented. Methods of RCS prediction are summarized, citing their advantages and disadvantages. Bistatic and monostatic RCS patterns for two wind turbine configurations, a horizontal axis three-blade design and a vertical axis helical design, are shown. The unique electromagnetic scattering features, the effect of materials, and methods of mitigating wind turbine clutter are also discussed.
[Fast neutron cross section measurements
1991-01-01
In the 14 MeV Neutron Laboratory, we have continued the development of a facility that is now the only one of its kind in operation in the United States. We have refined the klystron bunching system described in last year's report to the point that 1.2 nanosecond pulses have been directly measured. We have tested the pulse shape discrimination capability of our primary NE 213 neutron detector. We have converted the RF sweeper section of the beamline to a frequency of 1 MHz to replace the function of the high voltage pulser described in last year's report which proved to be difficult to maintain and unreliable in its operation. We have also overcome several other significant experimental difficulties, including a major problem with a vacuum leak in the main accelerator column. We have completed additional testing to prove the remainder of the generation and measurement systems, but overcoming some of these experimental difficulties has delayed the start of actual data taking. We are now in a position to begin our first series of ring geometry elastic scattering measurements, and these will be underway before the end of the current contract year. As part of our longer term planning, we are continuing the conceptual analysis of several schemes to improve the intensity of our current pulsed beam. These include the provision of a duoplasmatron ion source and/or the provision of preacceleration bunching. Additional details are given later in this report. A series of measurements were carried out at the Tandem Dynamatron Facility involving the irradiation of a series of yttrium foils and the determination of activation cross sections using absolute counting techniques. The experimental work has been completed, and final analysis of the cross section data will be completed within several months
K+ nucleus total cross sections
Sawafta, R.
1990-01-01
The scattering of K + mesons from nuclei has attracted considerable interest in the last few years. The K + holds a very special position as the weakest of all strongly interaction probes. The average cross section is not larger than about 10 mb at lab momenta below 800 MeV/c, corresponding to a mean free path in the nucleus larger than 5 fm. Thus the K + is capable of probing the entire volume of the nucleus. Single scattering of the K + with a nucleon in the nucleus dominates the nuclear scattering, and only small and calculable higher order corrections are needed. The nucleon is a dynamical entity and its internal structure can, in principle, be altered by its surrounding nuclear environment. This work reports an experiment in which the K + is used to compare the nucleon in the nucleus with a free nucleon
Terahertz radar cross section measurements.
Iwaszczuk, Krzysztof; Heiselberg, Henning; Jepsen, Peter Uhd
2010-12-06
We perform angle- and frequency-resolved radar cross section (RCS) measurements on objects at terahertz frequencies. Our RCS measurements are performed on a scale model aircraft of size 5-10 cm in polar and azimuthal configurations, and correspond closely to RCS measurements with conventional radar on full-size objects. The measurements are performed in a terahertz time-domain system with freely propagating terahertz pulses generated by tilted pulse front excitation of lithium niobate crystals and measured with sub-picosecond time resolution. The application of a time domain system provides ranging information and also allows for identification of scattering points such as weaponry attached to the aircraft. The shapes of the models and positions of reflecting parts are retrieved by the filtered back projection algorithm.
Cross-correlation analysis of Ge/Li/ spectra
MacDonald, R.; Robertson, A.; Kennett, T.J.; Prestwich, W.V.
1974-01-01
A sensitive technique is proposed for activation analysis using cross-correlation and improved spectral orthogonality achieved through use of a rectangular zero area digital filter. To test the accuracy and reliability of the cross-correlation procedure five spectra obtained with a Ge/Li detector were combined in different proportions. Gaussian distributed statistics were then added to the composite spectra by means of a pseudo-random number generator. The basis spectra used were 76 As, 82 Br, 72 Ga, 77 Ge, and room background. In general, when the basis spectra were combined in roughly comparable proportions the accuracy of the techique proved to be excelent (>1%). However, of primary importance was the ability of the correlation technique to identify low intensity components in the presence of high intensity components. It was found that the detection threshold for Ge, for example, was not reached until the Ge content in the unfiltered spectrum was <0.16%. (T.G.)
Cross section library DOSCROS77 (in the SAND-II format)
Zijp, W.L.; Nolthenius, H.J.; Borg, N.J.C.M. van der.
1977-08-01
The dosimetry cross section library DOSCROS77 is documented with tables, plots and cross section values averaged over a few reference spectra. This library is based on the ENDF/B-IV dosimetry file, supplemented with some other evaluations. The total number of reaction cross section sets incorporated in this library is 49 (+3 cover cross sections sets). The cross section data are available in a format which is suitable for the program SAND-II
Dielectronic recombination cross sections for H-like ions
Pindzola, M.S.; Badnell, N.R.; Griffin, D.C.
1990-01-01
Dielectronic recombination cross sections for several H-like atomic ions are calculated in an isolated-resonance, distorted-wave approximation. Fine-structure and configuration-interaction effects are examined in detail for the O 7+ cross section. Hartree-Fock, intermediate-coupled, multiconfiguration dielectronic recombination cross sections for O 7+ are then compared with the recent experimental measurements obtained with the Test Storage Ring in Heidelberg. The cross-section spectra line up well in energy and the shape of the main resonance structures are comparable. The experimental integrated cross sections differ by up to 20% from theory, but this may be due in part to uncertainties in the electron distribution function
Neutron cross sections: Book of curves
McLane, V.; Dunford, C.L.; Rose, P.F.
1988-01-01
Neuton Cross Sections: Book of Curves represents the fourth edition of what was previously known as BNL-325, Neutron Cross Sections, Volume 2, CURVES. Data is presented only for (i.e., intergrated) reaction cross sections (and related fission parameters) as a function of incident-neutron energy for the energy range 0.01 eV to 200 MeV. For the first time, isometric state production cross sections have been included. 11 refs., 4 figs
JENDL gas-production cross section file
Nakagawa, Tsuneo; Narita, Tsutomu
1992-05-01
The JENDL gas-production cross section file was compiled by taking cross-section data from JENDL-3 and by using the ENDF-5 format. The data were given to 23 nuclei or elements in light nuclei and structural materials. Graphs of the cross sections and brief description on their evaluation methods are given in this report. (author)
Integral nucleus-nucleus cross sections
Barashenkov, V.S.; Kumawat, H.
2003-01-01
Expressions approximating the experimental integral cross sections for elastic and inelastic interactions of light and heavy nuclei at the energies up to several GeV/nucleon are presented. The calculated cross sections are inside the corridor of experimental errors or very close to it. Described in detail FORTRAN code and a numerical example of the cross section approximation are also presented
[Fast neutron cross section measurements
Knoll, G.F.
1992-01-01
From its inception, the Nuclear Data Project at the University of Michigan has concentrated on two major objectives: (1) to carry out carefully controlled nuclear measurements of the highest possible reliability in support of the national nuclear data program, and (2) to provide an educational opportunity for students with interests in experimental nuclear science. The project has undergone a successful transition from a primary dependence on our photoneutron laboratory to one in which our current research is entirely based on a unique pulsed 14 MeV fast neutron facility. The new experimental facility is unique in its ability to provide nanosecond bursts of 14 MeV neutrons under conditions that are ''clean'' and as scatter-free as possible, and is the only one of its type currently in operation in the United States. It has been designed and put into operation primarily by graduate students, and has met or exceeded all of its important initial performance goals. We have reached the point of its routine operation, and most of the data are now in hand that will serve as the basis for the first two doctoral dissertations to be written by participating graduate students. Our initial results on double differential neutron cross sections will be presented at the May 1993 Fusion Reactor Technology Workshop. We are pleased to report that, after investing several years in equipment assembly and optimization, the project has now entered its ''data production'' phase
Relativistic photon-Maxwellian electron cross sections
Wienke, B.R.; Lathrop, B.L.; Devaney, J.J.
1986-01-01
Temperature corrected cross sections, complementing the Klein-Nishina set, are developed for astrophysical, plasma, and transport applications. The set is obtained from a nonlinear least squares fit to the exact photon-Maxwellian electron cross sections, using the static formula as the asymptotic basis. Two parameters are sufficient (two decimal places) to fit the exact cross sections over a range of 0-100 keV in electron temperature, and 0-1 MeV in incident photon energy. The fit is made to the total cross sections, yet the parameters predict both total and differential scattering cross sections well. Corresponding differential energy cross sections are less accurate. An extended fit to (just) the total cross sections, over the temperature and energy range 0-5 MeV, is also described. (author)
ExoCross: Spectra from molecular line lists
Yurchenko, Sergei N.; Al-Refaie, Ahmed; Tennyson, Jonathan
2018-03-01
ExoCross generates spectra and thermodynamic properties from molecular line lists in ExoMol, HITRAN, or several other formats. The code is parallelized and also shows a high degree of vectorization; it works with line profiles such as Doppler, Lorentzian and Voigt and supports several broadening schemes. ExoCross is also capable of working with the recently proposed method of super-lines. It supports calculations of lifetimes, cooling functions, specific heats and other properties. ExoCross converts between different formats, such as HITRAN, ExoMol and Phoenix, and simulates non-LTE spectra using a simple two-temperature approach. Different electronic, vibronic or vibrational bands can be simulated separately using an efficient filtering scheme based on the quantum numbers.
Background-cross-section-dependent subgroup parameters
Yamamoto, Toshihisa
2003-01-01
A new set of subgroup parameters was derived that can reproduce the self-shielded cross section against a wide range of background cross sections. The subgroup parameters are expressed with a rational equation which numerator and denominator are expressed as the expansion series of background cross section, so that the background cross section dependence is exactly taken into account in the parameters. The advantage of the new subgroup parameters is that they can reproduce the self-shielded effect not only by group basis but also by subgroup basis. Then an adaptive method is also proposed which uses fitting procedure to evaluate the background-cross-section-dependence of the parameters. One of the simple fitting formula was able to reproduce the self-shielded subgroup cross section by less than 1% error from the precise evaluation. (author)
Scattering cross section for various potential systems
Myagmarjav Odsuren
2017-08-01
Full Text Available We discuss the problems of scattering in this framework, and show that the applied method is very useful in the investigation of the effect of the resonance in the observed scattering cross sections. In this study, not only the scattering cross sections but also the decomposition of the scattering cross sections was computed for the α–α system. To obtain the decomposition of scattering cross sections into resonance and residual continuum terms, the complex scaled orthogonality condition model and the extended completeness relation are used. Applying the present method to the α–α and α–n systems, we obtained good reproduction of the observed phase shifts and cross sections. The decomposition into resonance and continuum terms makes clear that resonance contributions are dominant but continuum terms and their interference are not negligible. To understand the behavior of observed phase shifts and the shape of the cross sections, both resonance and continuum terms are calculated.
Scattering cross section for various potential systems
Odsuren, Myagmarjav; Khuukhenkhuu, Gonchigdorj; Davaa, Suren [Nuclear Research Center, School of Engineering and Applied Sciences, National University of Mongolia, Ulaanbaatar (Mongolia); Kato, Kiyoshi [Nuclear Reaction Data Centre, Faculty of Science, Hokkaido University, Sapporo (Japan)
2017-08-15
We discuss the problems of scattering in this framework, and show that the applied method is very useful in the investigation of the effect of the resonance in the observed scattering cross sections. In this study, not only the scattering cross sections but also the decomposition of the scattering cross sections was computed for the α–α system. To obtain the decomposition of scattering cross sections into resonance and residual continuum terms, the complex scaled orthogonality condition model and the extended completeness relation are used. Applying the present method to the α–α and α–n systems, we obtained good reproduction of the observed phase shifts and cross sections. The decomposition into resonance and continuum terms makes clear that resonance contributions are dominant but continuum terms and their interference are not negligible. To understand the behavior of observed phase shifts and the shape of the cross sections, both resonance and continuum terms are calculated.
Cross-section methodology in SIMMER
Soran, P.D.
1975-11-01
The cross-section methodology incorporated in the SIMMER code is described. Data base for all cross sections is the ENDF/B system with various progressing computer codes to group collapse and modify the group constants which are used in SIMMER. Either infinitely dilute cross sections or the Bondarenko formalism can be used in SIMMER. Presently only a microscopic treatment is considered, but preliminary macroscopic algorithms have been investigated
Cross-section methodology in SIMMER
Soran, P.D.
1976-05-01
The cross-section methodology incorporated in the SIMMER code is described. Data base for all cross sections is the ENDF/B system with various progressing computer codes to group collapse and modify the group constants which are used in SIMMER. Either infinitely dilute cross sections or the Bondarenko formalism can be used in SIMMER. Presently only a microscopic treatment is considered, but preliminary macroscopic algorithms have been investigated
High ET jet cross sections at CDF
Flaugher, B.
1996-08-01
The inclusive jet cross section for p anti p collisions at √s = 1.8 TeV as measured by the CDF collaboration will be presented. Preliminary CDF measurements of the Σ E T cross section at √s = 1.8 TeV and the central inclusive jet cross section at √s = 0.630 TeV will also be shown
Measurements of neutron capture cross sections
Nakajima, Yutaka
1984-01-01
A review of measurement techniques for the neutron capture cross sections is presented. Sell transmission method, activation method, and prompt gamma-ray detection method are described using examples of capture cross section measurements. The capture cross section of 238 U measured by three different prompt gamma-ray detection methods (large liquid scintillator, Moxon-Rae detector, and pulse height weighting method) are compared and their discrepancies are resolved. A method how to derive the covariance is described. (author)
Recommended activation detector cross sections (RNDL-82)
Bondars, Kh.Ya.; Lapenas, A.A.
1984-01-01
The results of the comparison between measured and calculated average cross sections in 5 benchmark experiments are presented. Calculations have been based on the data from 10 libraries of evaluated cross sections. The recommended library (RNDL-82) of the activation detector cross sections has been created on the basis of the comparison. RNDL-82, including 26 reactions, and the basic characteristics of the detectors are presented. (author)
Total neutron cross section of lead
Kanda, K.; Aizawa, O.
1976-01-01
The total thermal-neutron cross section of natural lead under various physical conditions was measured by the transmission method. It became clear that the total cross section at room temperature previously reported is lower than the present data. The total cross section at 400, 500, and 600 0 C, above the melting point of lead, 327 0 C, was also measured, and the changes in the cross section as a function of temperature were examined, especially near and below the melting point. The data obtained for the randomly oriented polycrystalline state at room temperature were in reasonable agreement with the theoretical values calculated by the THRUSH and UNCLE-TOM codes
Curves and tables of neutron cross sections
Nakagawa, Tsuneo; Asami, Tetsuo; Yoshida, Tadashi
1990-07-01
Neutron cross-section curves from the Japanese Evaluated Nuclear Data Library version 3, JENDL-3, are presented in both graphical and tabular form for users in a wide range of application areas in the nuclear energy field. The contents cover cross sections for all the main reactions induced by neutrons with an energy below 20 MeV including; total, elastic scattering, capture, and fission, (n,n'), (n,2n), (n,3n), (n,α), (n,p) reactions. The 2200 m/s cross-section values, resonance integrals, and Maxwellian- and fission-spectrum averaged cross sections are also tabulated. (author)
Electron collision cross sections of mercury
Suzuki, Susumu; Kuzuma, Kiyotaka; Itoh, Haruo
2006-01-01
In this paper, we propose a new collision cross section set for mercury which revises the original set summarized by Hayashi in 1989. Hanne reported three excitation collision cross sections (6 3 P 0 , 6 3 P 1 , 6 3 P 2 ) determined from an electron beam experiment in 1988. As a matter for regret, no attentive consideration was given to combining these three excitation cross sections with the cross section set of Hayashi. Therefore we propose a new set where these three excitation cross sections are included. In this study, other two excitation cross sections (6 1 P 1 , 6 3 D 3 ) except for the three excitation collision cross sections (6 3 P 0 , 6 3 P 1 , 6 3 P 2 ) are taken from the original set of Hayashi. The momentum transfer cross section and the ionization collision cross section are also taken from Hayashi. A Monte Carlo Simulation (MCS) technique is applied for evaluating our new cross section set. The present results of the electron drift velocity and the ionization coefficient are compared to experimental values. Agreement is secured in relation to the electron drift velocity for 1.5 Td 2 ) is the reduced electric field, E (V/cm) is the electric field, N (1/cm 3 ) is the number density of mercury atoms at 0degC, 1 Torr, E/N is also equal to 2.828 x 10 -17 E/p 0 from the relation of the ideal gas equation, p 0 (Torr) is gas pressure at 0degC, 1 Torr=1.33322 x 10 -2 N/cm -2 and 10 -17 V/cm 2 is called 1 Td. Thus it is ensured that our new cross section set is reasonable enough to be used up to 100 eV when considering with the electron drift velocity and the ionization coefficient. (author)
First measurement of the Rayleigh cross section
Naus, H.; Ubachs, W.
2000-01-01
Rayleigh cross section for N2, Ar and SF6 was performed using the technique of cavity ring-down spectroscopy (CRDS). The experiment was based on the assumption that scattering cross section is equal to the extinction in the absence of absorption. The theory explains the molecular origin of
Total cross section of highly excited strings
Lizzi, F.; Senda, I.
1990-01-01
The unpolarized total cross section for the joining of two highly excited strings is calculated. The calculation is performed by taking the average overall states in the given excitation levels of the initial strings. We find that the total cross section grows with the energy and momentum of the initial states. (author). 8 refs, 1 fig
Compilation of cross-sections. Pt. 1
Flaminio, V.; Moorhead, W.G.; Morrison, D.R.O.; Rivoire, N.
1983-01-01
A compilation of integral cross-sections for hadronic reactions is presented. This is an updated version of CERN/HERA 79-1, 79-2, 79-3. It contains all data published up to the beginning of 1982, but some more recent data have also been included. Plots of the cross-sections versus incident laboratory momentum are also given. (orig.)
Total cross section results for deuterium electrodisintegration
Skopik, D.M.; Murphy, J.J. II; Shin, Y.M.
1976-01-01
Theoretical total cross sections for deuterium electrodisintegration are presented as a function of incident electron energy. The cross section has been calculated using virtual photon theory with Partovi's photodisintegration calculation for E/subx/ > 10 MeV and effective range theory for E/subx/ 2 H(e, n) reaction in Tokamak reactors
Model cross section calculations using LAHET
Prael, R.E.
1992-01-01
The current status of LAHET is discussed. The effect of a multistage preequilibrium exciton model following the INC is examined for neutron emission benchmark calculations, as is the use of a Fermi breakup model for light nuclei rather than an evaporation model. Comparisons are made also for recent fission cross section experiments, and a discussion of helium production cross sections is presented
Vibrational enhancement of total breakup cross sections
Haftel, M.I.; Lim, T.K.
1984-01-01
This paper considers the role of multi-two-body bound states, namely vibrational excitations, on total three-body breakup cross-sections. Total cross-sections are usually easy to measure, and they play a fundamental role in chemical kinetics. (orig.)
Interference analysis of fission cross section
Toshkov, S.A.; Yaneva, N.B.
1976-01-01
The formula for the reaction cross-section based on the R-matrix formalism considering the interference between the two neighbouring resonances, referred to the same value of total momentum was used for the analysis of the cross-section of resonance neutron induced fission of 230Pu. The experimental resolution and thermal motion of the target nuclei were accounted for numerical integration
Compilation of cross-sections. Pt. 4
Alekhin, S.I.; Ezhela, V.V.; Lugovsky, S.B.; Tolstenkov, A.N.; Yushchenko, O.P.; Baldini, A.; Cobal, M.; Flaminio, V.; Capiluppi, P.; Giacomelli, G.; Mandrioli, G.; Rossi, A.M.; Serra, P.; Moorhead, W.G.; Morrison, D.R.O.; Rivoire, N.
1987-01-01
This is the fourth volume in our series of data compilations on integrated cross-sections for weak, electromagnetic, and strong interaction processes. This volume covers data on reactions induced by photons, neutrinos, hyperons, and K L 0 . It contains all data published up to June 1986. Plots of the cross-sections versus incident laboratory momentum are also given. (orig.)
Accurate measurements of neutron activation cross sections
Semkova, V.
1999-01-01
The applications of some recent achievements of neutron activation method on high intensity neutron sources are considered from the view point of associated errors of cross sections data for neutron induced reaction. The important corrections in -y-spectrometry insuring precise determination of the induced radioactivity, methods for accurate determination of the energy and flux density of neutrons, produced by different sources, and investigations of deuterium beam composition are considered as factors determining the precision of the experimental data. The influence of the ion beam composition on the mean energy of neutrons has been investigated by measurement of the energy of neutrons induced by different magnetically analysed deuterium ion groups. Zr/Nb method for experimental determination of the neutron energy in the 13-15 MeV energy range allows to measure energy of neutrons from D-T reaction with uncertainty of 50 keV. Flux density spectra from D(d,n) E d = 9.53 MeV and Be(d,n) E d = 9.72 MeV are measured by PHRS and foil activation method. Future applications of the activation method on NG-12 are discussed. (author)
Comparative analysis among several cross section sets
Caldeira, A.D.
1983-01-01
Critical parameters were calculated using the one dimensional multigroup transport theory for several cross section sets. Calculations have been performed for water mixtures of uranium metal, plutonium metal and uranium-thorium oxide, and for metallics systems, to determine the critical dimensions of geometries (sphere and cylinder). For this aim, the following cross section sets were employed: 1) multigroup cross section sets obtained from the GAMTEC-II code; 2) the HANSEN-ROACH cross section sets; 3) cross section sets from the ENDF/B-IV, processed by the NJOY code. Finally, we have also calculated the corresponding critical radius using the one dimensional multigroup transport DTF-IV code. The numerical results agree within a few percent with the critical values obtained in the literature (where the greatest discrepancy occured in the critical dimensions of water mixtures calculated with the values generated by the NJOY code), a very good results in comparison with similar works. (Author) [pt
Activation cross section data file, (1)
Yamamuro, Nobuhiro; Iijima, Shungo.
1989-09-01
To evaluate the radioisotope productions due to the neutron irradiation in fission of fusion reactors, the data for the activation cross sections ought to be provided. It is planning to file more than 2000 activation cross sections at final. In the current year, the neutron cross sections for 14 elements from Ni to W have been calculated and evaluated in the energy range 10 -5 to 20 MeV. The calculations with a simplified-input nuclear cross section calculation system SINCROS were described, and another method of evaluation which is consistent with the JENDL-3 were also mentioned. The results of cross section calculation are in good agreement with experimental data and they were stored in the file 8, 9 and 10 of ENDF/B format. (author)
Cross-sectional anatomy for computed tomography
Farkas, M.L.
1988-01-01
This self-study guide recognizes that evaluation and interpretation of CT-images demands a firm understanding of both cross-sectional anatomy and the principles of computed tomography. The objectives of this book are: to discuss the basic principles of CT, to stress the importance of cross-sectional anatomy to CT through study of selected cardinal transverse sections of head, neck, and trunk, to explain orientation and interpretation of CT-images with the aid of corresponding cross-sectional preparations
Is the quasielastic pion cross section really bigger than the pion-nucleus reaction cross section
Silbar, R.R.
1979-01-01
It is shown that soft pion charge exchanges may increase the inclusive (π + ,π 0 ') cross section, relative to the total quasielastic (π + ,π + ') cross section, by as much as a factor of two. 4 references
Partial cross sections near the higher resonances
Falk-Vairant, P.; Valladas, G.
1961-07-01
As a continuation of the report given at the 10. Rochester Conference, recent measurements of charge-exchange cross section and π 0 production in π - -p interactions are presented here. Section 1 gives a summary of the known results for the elastic, inelastic, and charge-exchange cross sections. Section 2 presents the behavior of the cross sections in the T=1/2 state, in order to discuss the resonances at 600 and 890 MeV. Section 3 discusses the charge-exchange scattering and the interference term between the T=1/2 and T=3/2 states. Section 4 presents some comments on inelastic processes. This report is reprinted from 'Reviews of Modern Physics', Vol. 33, No. 3, 362-367, July, 1961
Electron-impact cross sections of Ne
Tsurubuchi, S.; Arakawa, K.; Kinokuni, S.; Motohashi, K.
2000-01-01
Electron-impact absolute emission cross sections were measured for the 3p→3s transitions of Ne. Excitation functions of the 3s→2p first resonance lines were measured in the energy range from the threshold to 1000 eV by a polarization-free optical method and relative cross sections were normalized to the absolute values, (41.0±5.4)x10 -19 cm 2 for the 73.6 nm line and (7.1±1.0)x10 -19 cm 2 for the 74.4 nm line, which were determined at 500 eV. The integrated level-excitation cross sections of Suzuki et al for the 1s 2 and 1s 4 levels were combined with the corresponding 3p→3s cascade cross sections obtained in this paper to give absolute emission cross sections for the resonance lines. The level-excitation cross sections of the 1s 2 and 1s 4 states in Paschen notation were determined from the threshold to 1000 eV by subtracting 3p→3s cascade cross sections from the corresponding 3s→2p emission cross sections of the resonance lines. A large cascade contribution is found in the emission cross section of the resonance lines. It is 28.5% for the 73.6 nm line and 49.6% for the 74.4 nm line at 40 eV, and 17.0 and 61.8%, respectively, at 300 eV. (author)
NNLO jet cross sections by subtraction
Somogyi, G.; Bolzoni, P.; Trocsanyi, Z.
2010-06-01
We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of an earlier NNLO subtraction scheme over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state. (orig.)
Differential Top Cross-section Measurements
Fenton, Michael James; The ATLAS collaboration
2017-01-01
The top quark is the heaviest known fundamental particle. The measurement of the differential top-quark pair production cross-section provides a stringent test of advanced perturbative QCD calculations. The ATLAS collaboration has performed detailed measurements of those differential cross sections at a centre-of-mass energy of 13 TeV. This talk focuses on differential cross-section measurements in the lepton+jets final state, including using boosted top quarks to probe our understanding of top quark production in the TeV regime.
Hardon cross sections at ultra high energies
Yodh, G.B.
1987-01-01
A review of results on total hadronic cross sections at ultra high energies obtained from a study of longitudinal development of cosmic ray air showers is given. The experimental observations show that proton-air inelastic cross section increases from 275 mb to over 500 mb as the collision energy in the center of mass increases from 20 GeV to 20 TeV. The proton-air inelastic cross section, obtained from cosmic ray data at √s = 30 TeV, is compared with calculations using various different models for the energy variation of the parameters of the elementary proton-proton interaction. Three conclusions are derived
NNLO jet cross sections by subtraction
Somogyi, G.; Bolzoni, P. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Trocsanyi, Z. [CERN, Geneva (Switzerland)
2010-06-15
We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of an earlier NNLO subtraction scheme over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state. (orig.)
NNLO jet cross sections by subtraction
Somogyi, Gabor; Trocsanyi, Zoltan
2010-01-01
We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of the NNLO subtraction scheme of [1-4], over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state.
Average cross sections calculated in various neutron fields
Shibata, Keiichi
2002-01-01
Average cross sections have been calculated for the reactions contained in the dosimetry files, JENDL/D-99, IRDF-90V2, and RRDF-98 in order to select the best data for the new library IRDF-2002. The neutron spectra used in the calculations are as follows: 1) 252 Cf spontaneous fission spectrum (NBS evaluation), 2) 235 U thermal fission spectrum (NBS evaluation), 3) Intermediate-energy Standard Neutron Field (ISNF), 4) Coupled Fast Reactivity Measurement Facility (CFRMF), 5) Coupled thermal/fast uranium and boron carbide spherical assembly (ΣΣ), 6) Fast neutron source reactor (YAYOI), 7) Experimental fast reactor (JOYO), 8) Japan Material Testing Reactor (JMTR), 9) d-Li neutron spectrum with a 2-MeV deuteron beam. The items 3)-7) represent fast neutron spectra, while JMTR is a light water reactor. The Q-value for the d-Li reaction mentioned above is 15.02 MeV. Therefore, neutrons with energies up to 17 MeV can be produced in the d-Li reaction. The calculated average cross sections were compared with the measurements. Figures 1-9 show the ratios of the calculations to the experimental data which are given. It is found from these figures that the 58 Fe(n, γ) cross section in JENDL/D-99 reproduces the measurements in the thermal and fast reactor spectra better than that in IRDF-90V2. (author)
Radar cross sections for mesospheric echoes at Jicamarca
G. A. Lehmacher
2009-07-01
Full Text Available Radar cross sections (RCS of mesospheric layers at 50 MHz observed at Jicamarca, Peru, range from 10−18 to 10−16 m−1, three orders of magnitudes smaller than cross sections reported for polar mesospheric winter echoes during solar proton events and six orders of magnitude smaller than polar mesospheric summer echoes. Large RCS are found in thick layers around 70 km that also show wide radar spectra, which is interpreted as turbulent broadening. For typical atmospheric and ionospheric conditions, volume scattering RCS for stationary, homogeneous, isotropic turbulence at 3 m are also in the range 10−18 to 10−16 m−1, in reasonable agreement with measurements. Moreover, theory predicts maximum cross sections around 70 km, also in agreement with observations. Theoretical values are still a matter of order-of-magnitude estimation, since the Bragg scale of 3 m is near or inside the viscous subrange, where the form of the turbulence spectrum is not well known. In addition, steep electron density gradients can increase cross-sections significantly. For thin layers with large RCS and narrow spectra, isotropic turbulence theory fails and scattering or reflection from anisotropic irregularities may gain relevance.
Measurement of proton inelastic scattering cross sections on fluorine
Chiari, M., E-mail: chiari@fi.infn.it [Department of Physics and Astronomy, University of Florence and INFN Florence, Sesto Fiorentino (Italy); Caciolli, A. [Department of Physics and Astronomy, University of Padua and INFN Padua, Padova (Italy); Calzolai, G. [Department of Physics and Astronomy, University of Florence and INFN Florence, Sesto Fiorentino (Italy); Climent-Font, A. [CMAM, Universidad Autonoma de Madrid, Madrid (Spain); Lucarelli, F.; Nava, S. [Department of Physics and Astronomy, University of Florence and INFN Florence, Sesto Fiorentino (Italy)
2016-10-01
Differential cross-sections for proton inelastic scattering on fluorine, {sup 19}F(p,p’){sup 19}F, from the first five excited levels of {sup 19}F at 110, 197, 1346, 1459 and 1554 keV were measured for beam energies from 3 to 7 MeV at a scattering angle of 150° using a LiF thin target (50 μg/cm{sup 2}) evaporated on a self-supporting C thin film (30 μg/cm{sup 2}). Absolute differential cross-sections were calculated with a method not dependent on the absolute values of collected beam charge and detector solid angle. The validity of the measured inelastic scattering cross sections was then tested by successfully reproducing EBS spectra collected from a thick Teflon (CF{sub 2}) target. As a practical application of these measured inelastic scattering cross sections in elastic backscattering spectroscopy (EBS), the feasibility of quantitative light element (C, N and O) analysis in aerosol particulate matter samples collected on Teflon by EBS measurements and spectra simulation is demonstrated.
Calculation of the resonance cross section functions
Slipicevic, K.F.
1967-11-01
This paper includes the procedure for calculating the Doppler broadened line shape functions ψ and χ which are needed for calculation of resonance cross section functions. The obtained values are given in tables
Fission cross section measurements at intermediate energies
Laptev, Alexander
2005-01-01
The activity in intermediate energy particle induced fission cross-section measurements of Pu, U isotopes, minor actinides and sub-actinides in PNPI of Russia is reviewed. The neutron-induced fission cross-section measurements are under way in the wide energy range of incident neutrons from 0.5 MeV to 200 MeV at the GNEIS facility. In number of experiments at the GNEIS facility, the neutron-induced fission cross sections were obtained for many nuclei. In another group of experiments the proton-induced fission cross-section have been measured for proton energies ranging from 200 to 1000 MeV at 100 MeV intervals using the proton beam of PNPI synchrocyclotron. (author)
Measurement of multinucleon transfer cross-sections
Keywords. Ni(C, ), Fe(C, ), =C, C, B, B, Be, Be, Be, Be, Li, Li; = 60 MeV; measured reaction cross-section; elastic scattering angular distribution; deduced transfer probabilities and enhancement factors.
Capture cross sections on unstable nuclei
Tonchev, A. P.; Escher, J. E.; Scielzo, N.; Bedrossian, P.; Ilieva, R. S.; Humby, P.; Cooper, N.; Goddard, P. M.; Werner, V.; Tornow, W.; Rusev, G.; Kelley, J. H.; Pietralla, N.; Scheck, M.; Savran, D.; Löher, B.; Yates, S. W.; Crider, B. P.; Peters, E. E.; Tsoneva, N.; Goriely, S.
2017-09-01
Accurate neutron-capture cross sections on unstable nuclei near the line of beta stability are crucial for understanding the s-process nucleosynthesis. However, neutron-capture cross sections for short-lived radionuclides are difficult to measure due to the fact that the measurements require both highly radioactive samples and intense neutron sources. Essential ingredients for describing the γ decays following neutron capture are the γ-ray strength function and level densities. We will compare different indirect approaches for obtaining the most relevant observables that can constrain Hauser-Feshbach statistical-model calculations of capture cross sections. Specifically, we will consider photon scattering using monoenergetic and 100% linearly polarized photon beams. Challenges that exist on the path to obtaining neutron-capture cross sections for reactions on isotopes near and far from stability will be discussed.
Calculation of the resonance cross section functions
Slipicevic, K F [Institute of nuclear sciences Boris Kidric, Vinca, Beograd (Yugoslavia)
1967-11-15
This paper includes the procedure for calculating the Doppler broadened line shape functions {psi} and {chi} which are needed for calculation of resonance cross section functions. The obtained values are given in tables.
Pion-nucleus cross sections approximation
Barashenkov, V.S.; Polanski, A.; Sosnin, A.N.
1990-01-01
Analytical approximation of pion-nucleus elastic and inelastic interaction cross-section is suggested, with could be applied in the energy range exceeding several dozens of MeV for nuclei heavier than beryllium. 3 refs.; 4 tabs
Status of neutron dosimetry cross sections
Griffin, P.J.; Kelly, J.G.
1992-01-01
Several new cross section libraries, such as ENDF/B-VI(release 2), IRDF-90,JEF-2.2, and JENDL-3 Dosimetry, have recently been made available to the dosimetry community. the Sandia National Laboratories (SNL) Radiation Metrology Laboratory (RML) has worked with these libraries since pre-release versions were available. this paper summarizes the results of the intercomparison and testing of dosimetry cross sections. As a result of this analysis, a compendium of the best dosimetry cross sections was assembled from the available libraries for use within the SNL RML. this library, referred to as the SNLRML Library, contains 66 general dosimetry sensors and 3 special dosimeters unique to the RML sensor inventory. The SNLRML cross sections have been put into a format compatible with commonly used spectrum determination codes
Tachyonic ionization cross sections of hydrogenic systems
Tomaschitz, Roman [Department of Physics, Hiroshima University, 1-3-1 Kagami-yama, Higashi-Hiroshima 739-8526 (Japan)
2005-03-11
Transition rates for induced and spontaneous tachyon radiation in hydrogenic systems as well as the transversal and longitudinal ionization cross sections are derived. We investigate the interaction of the superluminal radiation field with matter in atomic bound-bound and bound-free transitions. Estimates are given for Ly-{alpha} transitions effected by superluminal quanta in hydrogen-like ions. The tachyonic photoelectric effect is scrutinized, in the Born approximation and at the ionization threshold. The angular maxima occur at different scattering angles in the transversal and longitudinal cross sections, which can be used to sift out longitudinal tachyonic quanta in a photon flux. We calculate the tachyonic ionization and recombination cross sections for Rydberg states and study their asymptotic scaling with respect to the principal quantum number. At the ionization threshold of highly excited states of order n {approx} 10{sup 4}, the longitudinal cross section starts to compete with photoionization, in recombination even at lower levels.
a cross-sectional analytic study 2014
Assessment of HIV/AIDS comprehensive correct knowledge among Sudanese university: a cross-sectional analytic study 2014. ... There are limited studies on this topic in Sudan. In this study we investigated the Comprehensive correct ...
Capture cross sections on unstable nuclei
Tonchev A.P.
2017-01-01
Full Text Available Accurate neutron-capture cross sections on unstable nuclei near the line of beta stability are crucial for understanding the s-process nucleosynthesis. However, neutron-capture cross sections for short-lived radionuclides are difficult to measure due to the fact that the measurements require both highly radioactive samples and intense neutron sources. Essential ingredients for describing the γ decays following neutron capture are the γ-ray strength function and level densities. We will compare different indirect approaches for obtaining the most relevant observables that can constrain Hauser-Feshbach statistical-model calculations of capture cross sections. Specifically, we will consider photon scattering using monoenergetic and 100% linearly polarized photon beams. Challenges that exist on the path to obtaining neutron-capture cross sections for reactions on isotopes near and far from stability will be discussed.
Methods for calculating anisotropic transfer cross sections
Cai, Shaohui; Zhang, Yixin.
1985-01-01
The Legendre moments of the group transfer cross section, which are widely used in the numerical solution of the transport calculation can be efficiently and accurately constructed from low-order (K = 1--2) successive partial range moments. This is convenient for the generation of group constants. In addition, a technique to obtain group-angle correlation transfer cross section without Legendre expansion is presented. (author)
Heisenberg rise of total cross sections
Ezhela, V.V.; Yushchenko, O.P.
1988-01-01
It is shown that on the basis of the original idea of Heisenberg on the quasiclassical picture of extended particle interactions one can construct a satisfactory description of the total cross sections, elastic cross sections, elastic diffractive slopes and mean charged multiplicities in the cm energy range from 5 to 900 GeV, and produce reasonable extrapolations up to several tens of TeV. 14 refs.; 7 figs.; 2 tabs
Evaluation methods for neutron cross section standards
Bhat, M.R.
1980-01-01
Methods used to evaluate the neutron cross section standards are reviewed and their relative merits, assessed. These include phase-shift analysis, R-matrix fit, and a number of other methods by Poenitz, Bhat, Kon'shin and the Bayesian or generalized least-squares procedures. The problems involved in adopting these methods for future cross section standards evaluations are considered, and the prospects for their use, discussed. 115 references, 5 figures, 3 tables
Ion-Collision Emission Excitation Cross Sections for Xenon Electric Thruster Plasmas
Sommerville, Jason D; King, Lyon B; Chiu, Yu-Hui; Dressler, Rainer A
2008-01-01
.... The cross sections are derived from ion beam luminescence spectra produced at single-collision conditions and at pressures for which radiation trapping effects were shown to be negligible. The Xe(exp...
SigmaCalc recent development and present status of the evaluated cross-sections for IBA
Gurbich, A.F.
2016-03-15
A new version of the SigmaCalc Internet site ( (http://sigmacalc.iate.obninsk.ru)) intended to provide evaluated differential cross-sections for spectra simulation is presented. Results of the revision of previously evaluated cross-sections and new evaluations including data for PIGE were made available to the IBA community through a simple interface. New SigmaCalc features allow users to compare evaluated differential cross-sections with the available results of the cross-section measurements taken on-the-fly from the IBANDL database and to validate them against benchmarks. The current status of the evaluated cross-sections for IBA is discussed.
Modelling interaction cross sections for intermediate and low energy ions
Toburen, L.H.; Shinpaugh, J.L.; Justiniano, E.L.B.
2002-01-01
When charged particles slow in tissue they undergo electron capture and loss processes than can have profound effects on subsequent interaction cross sections. Although a large amount of data exists for the interaction of bare charged particles with atoms and molecules, few experiments have been reported for these 'dressed' particles. Projectile electrons contribute to an impact-parameter-dependent screening of the projectile charge that precludes straightforward scaling of energy loss cross sections from those of bare charged particles. The objective of this work is to develop an analytical model for the energy-loss-dependent effects of screening on differential ionisation cross sections that can be used in track structure calculations for high LET ions. As a first step a model of differential ionisation cross sections for bare ions has been combined with a simple screening model to explore cross sections for intermediate and low energy dressed ions in collisions with atomic and molecular gas targets. The model is described briefly and preliminary results compared to measured electron energy spectra. (author)
Stealth metamaterial objects characterized in the far field by Radar Cross Section measurements
Iwaszczuk, Krzysztof; Fan, K.; Strikwerda, A. C.
Reflection spectra and radar cross sections (RCS) at terahertz frequencies are measured on structures incorporating absorbing metamaterials. Reduction of the RCS by the factor of 375 at the resonant frequencies is observed.......Reflection spectra and radar cross sections (RCS) at terahertz frequencies are measured on structures incorporating absorbing metamaterials. Reduction of the RCS by the factor of 375 at the resonant frequencies is observed....
Top quark production cross-section measurements
Chen, Ye; The ATLAS collaboration
2017-01-01
Measurements of the inclusive and differential cross-sections for top-quark pair and single top production cross sections in proton-proton collisions with the ATLAS detector at the Large Hadron Collider are presented at center-of-mass energies of 8 TeV and 13 TeV. The inclusive measurements reach high precision and are compared to the best available theoretical calculations. These measurements, including results using boosted tops, probe our understanding of top-pair production in the TeV regime. The results are compared to Monte Carlo generators implementing LO and NLO matrix elements matched with parton showers and NLO QCD calculations. For the t-channel single top measurement, the single top-quark and anti-top-quark total production cross-sections, their ratio, as well as differential cross sections are also presented. A measurement of the production cross-section of a single top quark in association with a W boson, the second largest single-top production mode, is also presented. Finally, measurements of ...
Homogenized group cross sections by Monte Carlo
Van Der Marck, S. C.; Kuijper, J. C.; Oppe, J.
2006-01-01
Homogenized group cross sections play a large role in making reactor calculations efficient. Because of this significance, many codes exist that can calculate these cross sections based on certain assumptions. However, the application to the High Flux Reactor (HFR) in Petten, the Netherlands, the limitations of such codes imply that the core calculations would become less accurate when using homogenized group cross sections (HGCS). Therefore we developed a method to calculate HGCS based on a Monte Carlo program, for which we chose MCNP. The implementation involves an addition to MCNP, and a set of small executables to perform suitable averaging after the MCNP run(s) have completed. Here we briefly describe the details of the method, and we report on two tests we performed to show the accuracy of the method and its implementation. By now, this method is routinely used in preparation of the cycle to cycle core calculations for HFR. (authors)
Prospects for Precision Neutrino Cross Section Measurements
Harris, Deborah A. [Fermilab
2016-01-28
The need for precision cross section measurements is more urgent now than ever before, given the central role neutrino oscillation measurements play in the field of particle physics. The definition of precision is something worth considering, however. In order to build the best model for an oscillation experiment, cross section measurements should span a broad range of energies, neutrino interaction channels, and target nuclei. Precision might better be defined not in the final uncertainty associated with any one measurement but rather with the breadth of measurements that are available to constrain models. Current experience shows that models are better constrained by 10 measurements across different processes and energies with 10% uncertainties than by one measurement of one process on one nucleus with a 1% uncertainty. This article describes the current status of and future prospects for the field of precision cross section measurements considering the metric of how many processes, energies, and nuclei have been studied.
NNLO jet cross sections by subtraction
Somogyi, G.; Bolzoni, P. [DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Trocsanyi, Z. [CERN PH-TH, on leave from University of Debrecen and Institute of Nuclear Research of HAS, H-4001 P.O.Box 51 (Hungary)
2010-08-15
We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of the NNLO subtraction scheme of Refs. [G. Somogyi, Z. Trocsanyi, and V. Del Duca, JHEP 06, 024 (2005), (arXiv:hep-ph/0502226); G. Somogyi and Z. Trocsanyi, (2006), (arXiv:hep-ph/0609041); G. Somogyi, Z. Trocsanyi, and V. Del Duca, JHEP 01, 070 (2007), (arXiv:hep-ph/0609042); G. Somogyi and Z. Trocsanyi, JHEP 01, 052 (2007), (arXiv:hep-ph/0609043)] over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state.
NNLO jet cross sections by subtraction
Somogyi, G.; Bolzoni, P.; Trocsanyi, Z.
2010-01-01
We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of the NNLO subtraction scheme of Refs. [G. Somogyi, Z. Trocsanyi, and V. Del Duca, JHEP 06, 024 (2005), (arXiv:hep-ph/0502226); G. Somogyi and Z. Trocsanyi, (2006), (arXiv:hep-ph/0609041); G. Somogyi, Z. Trocsanyi, and V. Del Duca, JHEP 01, 070 (2007), (arXiv:hep-ph/0609042); G. Somogyi and Z. Trocsanyi, JHEP 01, 052 (2007), (arXiv:hep-ph/0609043)] over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state.
Belanova, T.S.
1994-12-01
Data on the thermal neutron fission and capture cross-sections as well as their corresponding resonance integrals are reviewed and analysed. The data are classified according to the form of neutron spectra under investigation. The weighted mean values of the cross-sections and resonance integrals for every type of neutron spectra were adopted as evaluated data. (author). 87 refs, 2 tabs
Optical Model and Cross Section Uncertainties
Herman,M.W.; Pigni, M.T.; Dietrich, F.S.; Oblozinsky, P.
2009-10-05
Distinct minima and maxima in the neutron total cross section uncertainties were observed in model calculations using spherical optical potential. We found this oscillating structure to be a general feature of quantum mechanical wave scattering. Specifically, we analyzed neutron interaction with 56Fe from 1 keV up to 65 MeV, and investigated physical origin of the minima.We discuss their potential importance for practical applications as well as the implications for the uncertainties in total and absorption cross sections.
Cross sections for charm production by neutrinos
Ushida, N [Aichi Univ. of Education, Kariya (Japan). Dept. of Physics; Kondo, T [Fermi National Accelerator Lab., Batavia, IL (USA); Fujioka, G; Fukushima, J; Takahashi, Y; Tatsumi, S; Yokoyama, C [Kobe Univ. (Japan). Dept. of Physics; Homma, Y; Tsuzuki, Y [Kobe Univ. (Japan). Coll. of Liberal Arts; Bahk, S
1983-02-03
The production of charmed particles has been measured using a hybrid emulsion spectrometer in the Fermilab wide-band neutrino beam. The relative cross section for charged current charmed particle production is sigma(v -> ..mu../sup -/c)/sigma(v -> ..mu../sup -/) = 6.5 +- 1.9/1.8%, and the energy dependence of the cross section is presented. One event with charm pair production was observed. A limit of sigma(v -> ..mu..canti c)/sigma(v -> ..mu..c) < 6% (90% CL) is found for the ratio of charged current pair and single charm production.
Covariance Evaluation Methodology for Neutron Cross Sections
Herman,M.; Arcilla, R.; Mattoon, C.M.; Mughabghab, S.F.; Oblozinsky, P.; Pigni, M.; Pritychenko, b.; Songzoni, A.A.
2008-09-01
We present the NNDC-BNL methodology for estimating neutron cross section covariances in thermal, resolved resonance, unresolved resonance and fast neutron regions. The three key elements of the methodology are Atlas of Neutron Resonances, nuclear reaction code EMPIRE, and the Bayesian code implementing Kalman filter concept. The covariance data processing, visualization and distribution capabilities are integral components of the NNDC methodology. We illustrate its application on examples including relatively detailed evaluation of covariances for two individual nuclei and massive production of simple covariance estimates for 307 materials. Certain peculiarities regarding evaluation of covariances for resolved resonances and the consistency between resonance parameter uncertainties and thermal cross section uncertainties are also discussed.
Ecological Panel Inference from Repeated Cross Sections
Pelzer, Ben; Eisinga, Rob; Franses, Philip Hans
2004-01-01
This chapter presents a Markov chain model for the estimation of individual-level binary transitions from a time series of independent repeated cross-sectional (RCS) samples. Although RCS samples lack direct information on individual turnover, it is demonstrated here that it is possible with these
Validation of evaluated neutron standard cross sections
Badikov, S.; Golashvili, T.
2008-01-01
Some steps of the validation and verification of the new version of the evaluated neutron standard cross sections were carried out. In particular: -) the evaluated covariance data was checked for physical consistency, -) energy-dependent evaluated cross-sections were tested in most important neutron benchmark field - 252 Cf spontaneous fission neutron field, -) a procedure of folding differential standard neutron data in group representation for preparation of specialized libraries of the neutron standards was verified. The results of the validation and verification of the neutron standards can be summarized as follows: a) the covariance data of the evaluated neutron standards is physically consistent since all the covariance matrices of the evaluated cross sections are positive definite, b) the 252 Cf spectrum averaged standard cross-sections are in agreement with the evaluated integral data (except for 197 Au(n,γ) reaction), c) a procedure of folding differential standard neutron data in group representation was tested, as a result a specialized library of neutron standards in the ABBN 28-group structure was prepared for use in reactor applications. (authors)
Stability of tokamaks with elongated cross section
An, C.H.; Bateman, G.
1978-08-01
Fixed boundary n = 1 MHD instabilities are studied computationally as a function of diamagnetism (β/sub pol/) and current profile in elongated toroidal equilibria (1 2) or a diamagnetic plasma (β/sub pol/ > 1) with only a mildly elongated cross section
Modelisation of the fission cross section
Morariu, Claudia
2013-03-01
The neutron cross sections of four nuclear systems (n+ 235 U, n+ 233 U, n+ 241 Am and n+ 237 Np) are studied in the present document. The target nuclei of the first case, like 235 U and 239 Pu, have a large fission cross section after the absorption of thermal neutrons. These nuclei are called 'fissile' nuclei. The other type of nuclei, like 237 Np and 241 Am, fission mostly with fast neutrons, which exceed the fission threshold energy. These types of nuclei are called 'fertile'. The compound nuclei of the fertile nuclei have a binding energy higher than the fission barrier, while for the fissile nuclei the binding energy is lower than the fission barrier. In this work, the neutron induced cross sections for both types of nuclei are evaluated in the fast energy range. The total, reaction and shape-elastic cross sections are calculated by the coupled channel method of the optical model code ECIS, while the compound nucleus mechanism are treated by the statistical models implemented in the codes STATIS, GNASH and TALYS. The STATIS code includes a refined model of the fission process. Results from the theoretical calculations are compared with data retrieved from the experimental data base EXFOR. (author) [fr
Photoelectric absorption cross sections with variable abundances
Balucinska-Church, Monika; Mccammon, Dan
1992-01-01
Polynomial fit coefficients have been obtained for the energy dependences of the photoelectric absorption cross sections of 17 astrophysically important elements. These results allow the calculation of X-ray absorption in the energy range 0.03-10 keV in material with noncosmic abundances.
(, 3) Differential cross section of He
The angular distribution of the ﬁve-fold differential cross section for the electron impact double ionization of He (21 ) and He (23 ) has been studied. The kinematical conditions for maxima/minima in the angular distribution for the two cases have been compared. The two-step process for the double ionization is found to ...
Precise relative cross sections for np scattering
Goetz, J.; Brogli-Gysin, C.; Hammans, M.; Haffter, P.; Henneck, R.; Jourdan, J.; Masson, G.; Qin, L.M.; Robinson, S.; Sick, I.; Tuccillo, M.
1994-01-01
We present data on the differential cross section for neutron-proton scattering for an incident neutron energy of 67 MeV. These data allow a precise determination of the 1 P 1 phase which, in phase-shift analyses, is strongly correlated with the S-D amplitude which we are measuring via different observables. ((orig.))
Symmetric charge transfer cross section of uranium
Shibata, Takemasa; Ogura, Koichi
1995-03-01
Symmetric charge transfer cross section of uranium was calculated under consideration of reaction paths. In the charge transfer reaction a d 3/2 electron in the U atom transfers into the d-electron site of U + ( 4 I 9/2 ) ion. The J value of the U atom produced after the reaction is 6, 5, 4 or 3, at impact energy below several tens eV, only resonant charge transfer in which the product atom is ground state (J=6) takes place. Therefore, the cross section is very small (4-5 x 10 -15 cm 2 ) compared with that considered so far. In the energy range of 100-1000eV the cross section increases with the impact energy because near resonant charge transfer in which an s-electron in the U atom transfers into the d-electron site of U + ion. Charge transfer cross section between U + in the first excited state (289 cm -1 ) and U in the ground state was also obtained. (author)
LAMBDA p total cross-section measurement
CERN PhotoLab
1970-01-01
A view of the apparatus used for the LAMBDA p total cross-section measurement at the time of its installation. The hyperons decaying into a proton and a pion in the conical tank in front were detected in the magnet spectrometer in the upper half of the picture. A novel detection technique using exclusively multiwire proportional chambers was employed.
Measurement of MA fission cross sections at YAYOI
Ohkawachi, Yasushi; Ohki, Shigeo; Wakabayashi, Toshio [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center
1998-03-01
Fission cross section ratios of minor actinide nuclides (Am-241, Am-243) relative to U-235 in the fast neutron energy region have been measured using a back-to-back (BTB) fission chamber at YAYOI fast neutron source reactor. A small BTB fission chamber was developed to measure the fission cross section ratios in the center of the core at YAYOI reactor. Dependence of the fission cross section ratios on neutron spectra was investigated by changing the position of the detector in the reactor core. The measurement results were compared with the fission cross sections in the JENDL-3.2, ENDF/B-VI and JEF-2.2 libraries. It was found that calculated values of Am-241 using the JENDL-3.2, ENDF/B-VI and JEF-2.2 data are lower by about 15% than the measured value in the center of the core (the neutron average energy is 1.44E+6(eV)). And, good agreement can be seen the measured value and calculated value of Am-243 using the JENDL-3.2 data in the center of the core (the neutron average energy is 1.44E+6)(eV), but calculated values of Am-243 using the ENDF/B-VI and JEF-2.2 data are lower by 11% and 13% than the measured value. (author)
Measurement cross sections for radioisotopes production
Garrido, E.
2011-01-01
New radioactive isotopes for nuclear medicine can be produced using particle accelerators. This is one goal of Arronax, a high energy - 70 MeV - high intensity - 2*350 μA - cyclotron set up in Nantes. A priority list was established containing β - - 47 Sc, 67 Cu - β + - 44 Sc, 64 Cu, 82 Sr/ 82 Rb, 68 Ge/ 68 Ga - and α emitters - 211 At. Among these radioisotopes, the Scandium 47 and the Copper 67 have a strong interest in targeted therapy. The optimization of their productions required a good knowledge of their cross-sections but also of all the contaminants created during irradiation. We launched on Arronax a program to measure these production cross-sections using the Stacked-Foils' technique. It consists in irradiating several groups of foils - target, monitor and degrader foils - and in measuring the produced isotopes by γ-spectrometry. The monitor - nat Cu or nat Ni - is used to correct beam loss whereas degrader foils are used to lower beam energy. We chose to study the nat Ti(p,X) 47 Sc and 68 Zn(p,2p) 67 Cu reactions. Targets are respectively natural Titanium foil - bought from Goodfellow - and enriched Zinc 68 deposited on Silver. In the latter case, Zn targets were prepared in-house - electroplating of 68 Zn - and a chemical separation between Copper and Gallium isotopes has to be made before γ counting. Cross-section values for more than 40 different reactions cross-sections have been obtained from 18 MeV to 68 MeV. A comparison with the Talys code is systematically done. Several parameters of theoretical models have been studied and we found that is not possible to reproduce faithfully all the cross-sections with a given set of parameters. (author)
Neutron-induced fission cross sections
Weigmann, H.
1991-01-01
In the history of fission research, neutron-induced fission has always played the most important role. The practical importance of neutron-induced fission rests upon the fact that additional neutrons are produced in the fission process, and thus a chain reaction becomes possible. The practical applications of neutron-induced fission will not be discussed in this chapter, but only the physical properties of one of its characteristics, namely (n,f) cross sections. The most important early summaries on the subject are the monograph edited by Michaudon which also deals with the practical applications, the earlier review article on fission by Michaudon, and the review by Bjornholm and Lynn, in which neutron-induced fission receives major attention. This chapter will attempt to go an intermediate way between the very detailed theoretical treatment in the latter review and the cited monograph which emphasizes the applied aspects and the techniques of fission cross-section measurements. The more recent investigations in the field will be included. Section II will survey the properties of cross sections for neutron-induced fission and also address some special aspects of the experimental methods applied in their measurement. Section Ill will deal with the formal theory of neutron-induced nuclear reactions for the resolved resonance region and the region of statistical nuclear reactions. In Section IV, the fission width, or fission transmission coefficient, will be discussed in detail. Section V will deal with the broader structures due to incompletely damped vibrational resonances, and in particular will address the special case of thorium and neighboring isotopes. Finally, Section VI will briefly discuss parity violation effects in neutron-induced fission. 74 refs., 14 figs., 3 tabs
Nuclear cross section library for oil well logging analysis
Kodeli, I.; Kitsos, S.; Aldama, D.L.; Zefran, B.
2003-01-01
As part of the IRTMBA (Improved Radiation Transport Modelling for Borehole Applications) Project of the EU Community's 5 th Programme a special purpose multigroup cross section library to be used in the deterministic (as well as Monte Carlo) oil well logging particle transport calculations was prepared. This library is expected to improve the prediction of the neutron and gamma spectra at the detector positions of the logging tool, and their use for the interpretation of the neutron logging measurements was studied. Preparation and testing of this library is described. (author)
Sanami, Toshiya; Baba, Mamoru; Saito, Keiichiro; Ibara, Yasutaka; Hirakawa, Naohiro [Tohoku Univ., Sendai (Japan). Faculty of Engineering
1997-03-01
We are developing a method of (n,{alpha}) cross section measurement using gaseous samples in a gridded ionization chamber (GIC). This method enables cross section measurements in large solid angle without the distortion by the energy loss in a sample, but requires a method to estimate the detection efficiency. We solve this problem by using GIC signals and a tight neutron collimation. The validity of this method was confirmed through the {sup 12}C(n,{alpha}{sub 0}){sup 9}Be measurement. We applied this method to the {sup 16}O(n,{alpha}){sup 13}C cross section around 14.1 MeV. (author)
Rotational averaging of multiphoton absorption cross sections
Friese, Daniel H., E-mail: daniel.h.friese@uit.no; Beerepoot, Maarten T. P.; Ruud, Kenneth [Centre for Theoretical and Computational Chemistry, University of Tromsø — The Arctic University of Norway, N-9037 Tromsø (Norway)
2014-11-28
Rotational averaging of tensors is a crucial step in the calculation of molecular properties in isotropic media. We present a scheme for the rotational averaging of multiphoton absorption cross sections. We extend existing literature on rotational averaging to even-rank tensors of arbitrary order and derive equations that require only the number of photons as input. In particular, we derive the first explicit expressions for the rotational average of five-, six-, and seven-photon absorption cross sections. This work is one of the required steps in making the calculation of these higher-order absorption properties possible. The results can be applied to any even-rank tensor provided linearly polarized light is used.
Measurements of neutron spallation cross section. 2
Kim, E.; Nakamura, T. [Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center; Imamura, M.; Nakao, N.; Shibata, S.; Uwamino, Y.; Nakanishi, N.; Tanaka, Su.
1997-03-01
Neutron spallation cross section of {sup 59}Co(n,xn){sup 60-x}Co, {sup nat}Cu(n,sp){sup 56}Mn, {sup nat}Cu(n,sp){sup 58}Co, {sup nat}Cu(n,xn){sup 60}Cu, {sup nat}Cu(n,xn){sup 61}Cu and {sup nat}Cu(n,sp){sup 65}Ni was measured in the quasi-monoenergetic p-Li neutron fields in the energy range above 40 MeV which have been established at three AVF cyclotron facilities of (1) INS of Univ. of Tokyo, (2) TIARA of JAERI and (3) RIKEN. Our experimental data were compared with the ENDF/B-VI high energy file data by Fukahori and the calculated cross section data by Odano. (author)
Structured ion impact: Doubly differential cross sections
DuBois, R.D.
1987-01-01
The electron emission in coincidence with a projectile that has been ionized has been measured, thus making it possible to separate and identify electrons resulting from these various mechanisms. In 1985, coincidence doubly differential cross sections were measured for 400 to 750 keV/atomic mass unit (amu) He + impact on He, Ne, Ar, Kr, and H 2 O. Cross sections were measured for selected angles and for electron energies ranging from 10 to 1000 eV. Because of the coincidence mode of measurement, the total electron emission was subdivided into its target emission and its projectile emission components. The most interesting findings were that target ionization does not account for the electron emission spectrum at lower electron energies. A sizable percentage of these low-energy electrons were shown to originate as a result of simultaneous projectile/target ionizations. Similar features were observed for all targets and impact energies that were studied
Electron-collision cross sections for iodine
Zatsarinny, O.; Bartschat, K.; Garcia, G.; Blanco, F.; Hargreaves, L.R.; Jones, D.B.; Murrie, R.; Brunton, J.R.; Brunger, M.J.; Hoshino, M.; Buckman, S.J.
2011-01-01
We present results from a joint experimental and theoretical study of elastic electron scattering from atomic iodine. The experimental results were obtained by subtracting known cross sections from the measured data obtained with a pyrolyzed mixed beam containing a variety of atomic and molecular species. The calculations were performed using both a fully relativistic Dirac B-spline R-matrix (close-coupling) method and an optical model potential approach. Given the difficulty of the problem, the agreement between the two sets of theoretical predictions and the experimental data for the angle-differential and the angle-integrated elastic cross sections at 40 eV and 50 eV is satisfactory.
Absolute partial photoionization cross sections of ethylene
Grimm, F. A.; Whitley, T. A.; Keller, P. R.; Taylor, J. W.
1991-07-01
Absolute partial photoionization cross sections for ionization out of the first four valence orbitals to the X 2B 3u, A 2B 3g, B 2A g and C 2B 2u states of the C 2H 4+ ion are presented as a function of photon energy over the energy range from 12 to 26 eV. The experimental results have been compared to previously published relative partial cross sections for the first two bands at 18, 21 and 24 eV. Comparison of the experimental data with continuum multiple scattering Xα calculations provides evidence for extensive autoionization to the X 2B 3u state and confirms the predicted shape resonances in ionization to the A 2B 3g and B 2A g states. Identification of possible transitions for the autoionizing resonances have been made using multiple scattering transition state calculations on Rydberg excited states.
Radar cross section measurements using terahertz waves
Iwaszczuk, Krzysztof; Heiselberg, Henning; Jepsen, Peter Uhd
2010-01-01
Radar cross sections at terahertz frequencies are measured on scale models of aircrafts. A time domain broadband THz system generates freely propagating THz pulses measured with sub-picosecond time resolution. The THz radiation is generated using fs laser pulses by optical rectification...... in order to measure realistic radar cross sections. RCS polar and azimuthal angle plots of F-16 and F-35 are presented....... in a lithium niobate crystal with application of the tilted wave front method, resulting in high electric field THz pulses with a broad band spectrum from 100 GHz up to 4 THz. The corresponding wave lengths are two orders of magnitude smaller than normal radars and we therefore use scale models of size 5-10 cm...
Electron Capture Cross Sections for Stellar Nucleosynthesis
P. G. Giannaka
2015-01-01
Full Text Available In the first stage of this work, we perform detailed calculations for the cross sections of the electron capture on nuclei under laboratory conditions. Towards this aim we exploit the advantages of a refined version of the proton-neutron quasiparticle random-phase approximation (pn-QRPA and carry out state-by-state evaluations of the rates of exclusive processes that lead to any of the accessible transitions within the chosen model space. In the second stage of our present study, we translate the abovementioned e--capture cross sections to the stellar environment ones by inserting the temperature dependence through a Maxwell-Boltzmann distribution describing the stellar electron gas. As a concrete nuclear target we use the 66Zn isotope, which belongs to the iron group nuclei and plays prominent role in stellar nucleosynthesis at core collapse supernovae environment.
Test of RIPL-2 cross section calculations
Herman, M.
2002-01-01
The new levels and optical segments and microscopic HF-BCS level densities (part of the density segment) were tested in practical calculations of cross sections for neutron induced reactions on 22 targets (40-Ca, 47-Ti, 52-Cr, 55-Mn, 58-Ni, 63-Cu, 71-Ga, 80-Se, 92-Mo, 93-Nb, 100-Mo, 109-Ag, 114-Cd, 124-Sn, 127-I, 133-Cs, 140-Ce, 153-Eu, 169-Tm, 186-W, 197-Au, 208-Pb). For each target all reactions involving up to 3 neutron, 1 proton and 1 α-particle emissions (subject to actual reaction thresholds) were considered in the incident energy range from 1 keV up to 20 MeV (in some cases up to 27 MeV). In addition, total, elastic, and neutron capture cross sections were calculated
Double differential cross sections of ethane molecule
Kumar, Rajeev
2018-05-01
Partial and total double differential cross sections corresponding to various cations C2H6+, C2H4+, C2H5+, C2H3+, C2H2+, CH3+, H+, CH2+, C2H+, H2+, CH+, H3+, C2+ and C+ produced during the direct and dissociative electron ionization of Ethane (C2H6) molecule have been calculated at fixed impinging electron energies 200 and 500eV by using modified Jain-Khare semi empirical approach. The calculation for double differential cross sections is made as a function of energy loss suffered by primary electron and angle of incident. To the best of my knowledge no other data is available for the comparison.
Elliptical cross section fuel rod study II
Taboada, H.; Marajofsky, A.
1996-01-01
In this paper it is continued the behavior analysis and comparison between cylindrical fuel rods of circular and elliptical cross sections. Taking into account the accepted models in the literature, the fission gas swelling and release were studied. An analytical comparison between both kinds of rod reveals a sensible gas release reduction in the elliptical case, a 50% swelling reduction due to intragranular bubble coalescence mechanism and an important swelling increase due to migration bubble mechanism. From the safety operation point of view, for the same linear power, an elliptical cross section rod is favored by lower central temperatures, lower gas release rates, greater gas store in ceramic matrix and lower stored energy rates. (author). 6 refs., 8 figs., 1 tab
Weigel, H.; Michel, R.; Herr, W.
1975-01-01
A total of 24 cross sections was determined for (n,p)-, (n,α)-, (n,2n)-, and (n,np + pn + d)-reactions of fast (so called '14 MeV') neutrons on the elements Sc, Ni, Ge, Pd, Cd, Sm, Dy, Gd, and Yb. 58 Ni(n,p) 58 Co served as monitor reaction. It is a special feature of this work that calculated neutron energy spectra for the '14 MeV' n-tube (Type Philips 18602) were considered, thus enabling us to supply each individual sigma-value with the respective n-energy distribution. On the basis of an extensive literature search (up to the beginning of 1973) the sigma-data were compared with experimental results of other authors and with those deduced from the statistical model. For some nuclides (e.g. 58 Ni, 154 Gd, 168 Yb, 176 Yb) it was possible to show the limits of applicability of the latter model. Summarizing, 12 cross sections and 3 isomeric ratios, nearly all of which belong to reaction products with rather long half-lifes, were determined for the first time. (orig.) [de
Weigel, H; Michel, R; Herr, W [Koeln Univ. (F.R. Germany). Inst. fuer Kernchemie
1975-01-01
A total of 24 cross sections was determined for (n,p), (n,..cap alpha..), (n,2n), and (n,np + pn + d) reactions of fast (so called '14-MeV') neutrons on the elements Sc, Ni, Ge, Pd, Cd, Sm, Dy, Gd, and Yb. /sup 58/Ni(n,p)/sup 58/Co served as monitor reaction. It is a special feature of this work that calculated neutron energy spectra for the '14 MeV' n-tube (Type Philips 18602) were considered; each individual sigma value could thus be supplied with the respective n-energy distribution. On the basis of an extensive literature search (up to the beginning of 1973), the sigma data were compared with experimental results of other authors and with those deduced from the statistical model. For some nuclides (e.g. /sup 58/Ni, /sup 154/Gd, /sup 168/Yb, /sup 176/Yb) it was possible to show the limits of applicability of the latter model. Summarizing, 12 cross sections and 3 isomeric ratios, nearly all of which belong to reaction products with rather long half-lifes, were determined for the first time.
Electron collision cross sections and radiation chemistry
Hatano, Y.
1983-01-01
A survey is given of the cross section data needs in radiation chemistry, and of the recent progress in electron impact studies on dissociative excitation of molecules. In the former some of the important target species, processes, and collision energies are presented, while in the latter it is demonstrated that radiation chemistry is a source of new ideas and information in atomic collision research. 37 references, 4 figures
Absolute photoionization cross sections of atomic oxygen
Samson, J. A. R.; Pareek, P. N.
1985-01-01
The absolute values of photoionization cross sections of atomic oxygen were measured from the ionization threshold to 120 A. An auto-ionizing resonance belonging to the 2S2P4(4P)3P(3Do, 3So) transition was observed at 479.43 A and another line at 389.97 A. The experimental data is in excellent agreement with rigorous close-coupling calculations that include electron correlations in both the initial and final states.
Total dissociation cross section of halo nuclei
Formanek, J. [Karlova Univ., Prague (Czech Republic). Fakulta Matematicko-Fyzikalni; Lombard, R.J. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire
1996-10-01
Calculations of the total dissociation cross section is performed in the impact parameter representation. The case of {sup 11}Be and {sup 11}Li loosing one and two neutron(s), respectively, by collision on a {sup 12}C target, which remains in its ground state are discussed. The results are found to depend essentially on the rms radius of the halo wave function. (author). 12 refs.
Measurements of Fission Cross Sections of Actinides
Wiescher, M; Cox, J; Dahlfors, M
2002-01-01
A measurement of the neutron induced fission cross sections of $^{237}$Np, $^{241},{243}$Am and of $^{245}$Cm is proposed for the n_TOF neutron beam. Two sets of fission detectors will be used: one based on PPAC counters and another based on a fast ionization chamber (FIC). A total of 5x10$^{18}$ protons are requested for the entire fission measurement campaign.
Cross section of the CMS solenoid
Tejinder S. Virdee, CERN
2005-01-01
The pictures show a cross section of the CMS solenoid. One can see four layers of the superconducting coil, each of which contains the superconductor (central part, copper coloured - niobium-titanium strands in a copper coating, made into a "Rutherford cable"), surrounded by an ultra-pure aluminium as a magnetic stabilizer, then an aluminium alloy as a mechanical stabilizer. Besides the four layers there is an aluminium mechanical piece that includes pipes that transport the liquid helium.
Cross sections for multistep direct reactions
Demetriou, Paraskevi; Marcinkowski, Andrzej; Marianski, Bohdan
2002-01-01
Inelastic scattering and charge-exchange reactions have been analysed at energies ranging from 14 to 27 MeV using the modified multistep direct reaction theory (MSD) of Feshbach, Kerman and Koonin. The modified theory considers the non-DWBA matrix elements in the MSD cross section formulae and includes both incoherent particle-hole excitations and coherent collective excitations in the continuum, according to the prescriptions. The results show important contributions from multistep processes at all energies considered. (author)
Capture cross sections for very heavy systems
Rowley, N.; Grar, N.; Ntshangase, S.S.
2006-01-01
In intermediate-mass systems, collective excitations of the target and projectile can greatly enhance the sub-barrier capture cross section σ cap by giving rise to a distribution of Coulomb barriers. For such systems, capture essentially leads directly to fusion (formation of a compound nucleus (CN)), which then decays through the emission of light particles (neutrons, protons, and alpha particles). Thus the evaporation-residue (ER) cross section is essentially equal to σ cap . For heavier systems the experimental situation is significantly more complicated due to the presence of quasifission (QF) (rapid separation into two fragments before the CN is formed) and by fusion-fission (FF) of the CN itself. Thus three cross sections need to be measured in order to evaluate σ cap . Although the ER essentially recoil along the beam direction. QF and FF fragments are scattered to all angles and require the measurement of angular distribution in order to obtain the excitation function and barrier distribution for capture. Two other approaches to this problem exist. If QF is not important, one can still measure just the ER cross section and try to reconstruct the corresponding σ cap through use of an evaporation-model code that takes account of the FF degree of freedom. Some earlier results on σ cap obtained in this way will be re-analyzed with detail coupled-channels calculations, and the extra-push phenomenon discussed. One may also try to obtain σ cap by exploiting unitarity, that is, by measuring instead the flux of particles corresponding to quasielastic (QE) scattering from the Coulomb barrier. Some new QE results obtained for the 86 Kr + 208 Pb system at iThemba LABS in South Africa will be presented [ru
Inclusive jet cross section at D0
Bhattacharjee, M.
1996-09-01
Preliminary measurement of the central (|η| ≤ 0.5) inclusive jet cross sections for jet cone sizes of 1.0, 0.7, and 0.5 at D null based on the 1992-1993 (13.7 pb -1 ) and 1994-1995 (90 pb -1 ) data samples are presented. Comparisons to Next-to-Leading Order (NLO) Quantum Chromodynamics (QCD) calculations are made
Fully double-logarithm-resummed cross sections
Albino, S.; Bolzoni, P.; Kniehl, B.A.; Kotikov, A.
2011-01-01
We calculate the complete double logarithmic contribution to cross sections for semi-inclusive hadron production in the modified minimal-subtraction (MS-bar) scheme by applying dimensional regularization to the double logarithm approximation. The full double logarithmic contribution to the coefficient functions for inclusive hadron production in e + e - annihilation is obtained in this scheme for the first time. Our result agrees with all fixed order results in the literature, which extend to next-to-next-to-leading order.
Atomic-process cross section data, 1
1974-12-01
Compiled by the Data Study Group, the data are intended for fusion plasma physics research. Cross sections of the latest experimental and theoretic studies cover the processes involving H,D,T as principal plasma materials as well as photons and electrons: emission and absorption of electromagnetic wave, electron collision, ion collision, recombination, neutral atom mutual collision, etc. Edition is so made to enable the future renewal by users. (J.P.N.)
Neutron capture cross section of ^243Am
Jandel, M.
2009-10-01
The Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory (LANL) was used for neutron capture cross section measurement on ^243Am. The high granularity of DANCE (160 BaF2 detectors in a 4π geometry) enables the efficient detection of prompt gamma-rays following neutron capture. DANCE is located on the 20.26 m neutron flight path 14 (FP14) at the Manuel Lujan Jr. Neutron Scattering Center at the Los Alamos Neutron Science Center (LANSCE). The methods and techniques established in [1] were used for the determination of the ^243Am neutron capture cross section. The cross sections were obtained in the range of neutron energies from 0.02 eV to 400 keV. The resonance region was analyzed using SAMMY7 and resonance parameters were extracted. The results will be compared to existing evaluations and calculations. Work was performed under the auspices of the U.S. Department of Energy at Los Alamos National Laboratory by the Los Alamos National Security, LLC under Contract No. DE-AC52-06NA25396 and at Lawrence Livermore National Laboratory by the Lawrence Livermore National Security, LLC under Contract No. DE-AC52-07NA27344. [4pt] [1] M. Jandel et al., Phys. Rev. C78, 034609 (2008)
MXS cross-section preprocessor user's manual
Parker, F.; Ishikawa, M.; Luck, L.
1987-03-01
The MXS preprocessor has been designed to reduce the execution time of programs using isotopic cross-section data and to both reduce the execution time and improve the accuracy of shielding-factor interpolation in the SIMMER-II accident analysis program. MXS is a dual-purpose preprocessing code to: (1) mix isotopes into materials and (2) fit analytic functions to the shelf-shielding data. The program uses the isotope microscopic neutron cross-section data from the CCCC standard interface file ISOTXS and the isotope Bondarenko self-shielding data from the CCCC standard interface file BRKOXS to generate cross-section and self-shielding data for materials. The materials may be a mixture of several isotopes. The self-shielding data for the materials may be the actual shielding factors or a set of coefficients for functions representing the background dependence of the shielding factors. A set of additional data is given to describe the functions necessary to interpolate the shielding factors over temperature
Neutron capture cross sections of Kr
Fiebiger Stefan
2017-01-01
Full Text Available Neutron capture and β− -decay are competing branches of the s-process nucleosynthesis path at 85Kr [1], which makes it an important branching point. The knowledge of its neutron capture cross section is therefore essential to constrain stellar models of nucleosynthesis. Despite its importance for different fields, no direct measurement of the cross section of 85Kr in the keV-regime has been performed. The currently reported uncertainties are still in the order of 50% [2, 3]. Neutron capture cross section measurements on a 4% enriched 85Kr gas enclosed in a stainless steel cylinder were performed at Los Alamos National Laboratory (LANL using the Detector for Advanced Neutron Capture Experiments (DANCE. 85Kr is radioactive isotope with a half life of 10.8 years. As this was a low-enrichment sample, the main contaminants, the stable krypton isotopes 83Kr and 86Kr, were also investigated. The material was highly enriched and contained in pressurized stainless steel spheres.
Measurement of actinide neutron cross sections
Firestone, Richard B.; Nitsche, Heino; Leung, Ka-Ngo; Perry, DaleL.; English, Gerald
2003-01-01
The maintenance of strong scientific expertise is critical to the U.S. nuclear attribution community. It is particularly important to train students in actinide chemistry and physics. Neutron cross-section data are vital components to strategies for detecting explosives and fissile materials, and these measurements require expertise in chemical separations, actinide target preparation, nuclear spectroscopy, and analytical chemistry. At the University of California, Berkeley and the Lawrence Berkeley National Laboratory we have trained students in actinide chemistry for many years. LBNL is a leader in nuclear data and has published the Table of Isotopes for over 60 years. Recently, LBNL led an international collaboration to measure thermal neutron capture radiative cross sections and prepared the Evaluated Gamma-ray Activation File (EGAF) in collaboration with the IAEA. This file of 35, 000 prompt and delayed gamma ray cross-sections for all elements from Z=1-92 is essential for the neutron interrogation of nuclear materials. LBNL has also developed new, high flux neutron generators and recently opened a 1010 n/s D+D neutron generator experimental facility
Quality Quantification of Evaluated Cross Section Covariances
Varet, S.; Dossantos-Uzarralde, P.; Vayatis, N.
2015-01-01
Presently, several methods are used to estimate the covariance matrix of evaluated nuclear cross sections. Because the resulting covariance matrices can be different according to the method used and according to the assumptions of the method, we propose a general and objective approach to quantify the quality of the covariance estimation for evaluated cross sections. The first step consists in defining an objective criterion. The second step is computation of the criterion. In this paper the Kullback-Leibler distance is proposed for the quality quantification of a covariance matrix estimation and its inverse. It is based on the distance to the true covariance matrix. A method based on the bootstrap is presented for the estimation of this criterion, which can be applied with most methods for covariance matrix estimation and without the knowledge of the true covariance matrix. The full approach is illustrated on the 85 Rb nucleus evaluations and the results are then used for a discussion on scoring and Monte Carlo approaches for covariance matrix estimation of the cross section evaluations
Total neutron cross section for 181Ta
Schilling K.-D.
2010-10-01
Full Text Available The neutron time of flight facility nELBE, produces fast neutrons in the energy range from 0.1 MeV to 10 MeV by impinging a pulsed relativistic electron beam on a liquid lead circuit [1]. The short beam pulses (∼10 ps and a small radiator volume give an energy resolution better than 1% at 1 MeV using a short flight path of about 6 m, for neutron TOF measurements. The present neutron source provides 2 ⋅ 104 n/cm2s at the target position using an electron charge of 77 pC and 100 kHz pulse repetition rate. This neutron intensity enables to measure neutron total cross section with a 2%–5% statistical uncertainty within a few days. In February 2008, neutron radiator, plastic detector [2] and data acquisition system were tested by measurements of the neutron total cross section for 181Ta and 27Al. Measurement of 181Ta was chosen because lack of high quality data in an anergy region below 700 keV. The total neutron cross – section for 27Al was measured as a control target, since there exists data for 27Al with high resolution and low statistical error [3].
NNLO jet cross sections by subtraction
Somogyi, G.; Bolzoni, P.; Trócsányi, Z.
2010-08-01
We report on the computation of a class of integrals that appear when integrating the so-called iterated singly-unresolved approximate cross section of the NNLO subtraction scheme of Refs. [G. Somogyi, Z. Trócsányi, and V. Del Duca, JHEP 06, 024 (2005), arXiv:hep-ph/0502226; G. Somogyi and Z. Trócsányi, (2006), arXiv:hep-ph/0609041; G. Somogyi, Z. Trócsányi, and V. Del Duca, JHEP 01, 070 (2007), arXiv:hep-ph/0609042; G. Somogyi and Z. Trócsányi, JHEP 01, 052 (2007), arXiv:hep-ph/0609043] over the factorised phase space of unresolved partons. The integrated approximate cross section itself can be written as the product of an insertion operator (in colour space) times the Born cross section. We give selected results for the insertion operator for processes with two and three hard partons in the final state.
Cross-spectra over the sea from observations and mesoscale modelling
Vincent, Claire Louise; Larsén, Xiaoli Guo; Larsen, Søren Ejling
2013-01-01
of the cross-correlation function and an exponentially decaying coherence function are fitted to the normalized cospectra and quadrature spectra. The expressions are shown to be a good fit to the spectra calculated from the WRF simulations and to the observed spectra for directions with a long sea-fetch, which...
Absolute photoionization cross-section of the methyl radical.
Taatjes, Craig A; Osborn, David L; Selby, Talitha M; Meloni, Giovanni; Fan, Haiyan; Pratt, Stephen T
2008-10-02
The absolute photoionization cross-section of the methyl radical has been measured using two completely independent methods. The CH3 photoionization cross-section was determined relative to that of acetone and methyl vinyl ketone at photon energies of 10.2 and 11.0 eV by using a pulsed laser-photolysis/time-resolved synchrotron photoionization mass spectrometry method. The time-resolved depletion of the acetone or methyl vinyl ketone precursor and the production of methyl radicals following 193 nm photolysis are monitored simultaneously by using time-resolved synchrotron photoionization mass spectrometry. Comparison of the initial methyl signal with the decrease in precursor signal, in combination with previously measured absolute photoionization cross-sections of the precursors, yields the absolute photoionization cross-section of the methyl radical; sigma(CH3)(10.2 eV) = (5.7 +/- 0.9) x 10(-18) cm(2) and sigma(CH3)(11.0 eV) = (6.0 +/- 2.0) x 10(-18) cm(2). The photoionization cross-section for vinyl radical determined by photolysis of methyl vinyl ketone is in good agreement with previous measurements. The methyl radical photoionization cross-section was also independently measured relative to that of the iodine atom by comparison of ionization signals from CH3 and I fragments following 266 nm photolysis of methyl iodide in a molecular-beam ion-imaging apparatus. These measurements gave a cross-section of (5.4 +/- 2.0) x 10(-18) cm(2) at 10.460 eV, (5.5 +/- 2.0) x 10(-18) cm(2) at 10.466 eV, and (4.9 +/- 2.0) x 10(-18) cm(2) at 10.471 eV. The measurements allow relative photoionization efficiency spectra of methyl radical to be placed on an absolute scale and will facilitate quantitative measurements of methyl concentrations by photoionization mass spectrometry.
Vacuum ultraviolet photoionization cross section of the hydroxyl radical
Dodson, Leah G.; Savee, John D.; Gozem, Samer; Shen, Linhan; Krylov, Anna I.; Taatjes, Craig A.; Osborn, David L.; Okumura, Mitchio
2018-05-01
The absolute photoionization spectrum of the hydroxyl (OH) radical from 12.513 to 14.213 eV was measured by multiplexed photoionization mass spectrometry with time-resolved radical kinetics. Tunable vacuum ultraviolet (VUV) synchrotron radiation was generated at the Advanced Light Source. OH radicals were generated from the reaction of O(1D) + H2O in a flow reactor in He at 8 Torr. The initial O(1D) concentration, where the atom was formed by pulsed laser photolysis of ozone, was determined from the measured depletion of a known concentration of ozone. Concentrations of OH and O(3P) were obtained by fitting observed time traces with a kinetics model constructed with literature rate coefficients. The absolute cross section of OH was determined to be σ(13.436 eV) = 3.2 ± 1.0 Mb and σ(14.193 eV) = 4.7 ± 1.6 Mb relative to the known cross section for O(3P) at 14.193 eV. The absolute photoionization spectrum was obtained by recording a spectrum at a resolution of 8 meV (50 meV steps) and scaling to the single-energy cross sections. We computed the absolute VUV photoionization spectrum of OH and O(3P) using equation-of-motion coupled-cluster Dyson orbitals and a Coulomb photoelectron wave function and found good agreement with the observed absolute photoionization spectra.
Vacuum ultraviolet photoionization cross section of the hydroxyl radical.
Dodson, Leah G; Savee, John D; Gozem, Samer; Shen, Linhan; Krylov, Anna I; Taatjes, Craig A; Osborn, David L; Okumura, Mitchio
2018-05-14
The absolute photoionization spectrum of the hydroxyl (OH) radical from 12.513 to 14.213 eV was measured by multiplexed photoionization mass spectrometry with time-resolved radical kinetics. Tunable vacuum ultraviolet (VUV) synchrotron radiation was generated at the Advanced Light Source. OH radicals were generated from the reaction of O( 1 D) + H 2 O in a flow reactor in He at 8 Torr. The initial O( 1 D) concentration, where the atom was formed by pulsed laser photolysis of ozone, was determined from the measured depletion of a known concentration of ozone. Concentrations of OH and O( 3 P) were obtained by fitting observed time traces with a kinetics model constructed with literature rate coefficients. The absolute cross section of OH was determined to be σ(13.436 eV) = 3.2 ± 1.0 Mb and σ(14.193 eV) = 4.7 ± 1.6 Mb relative to the known cross section for O( 3 P) at 14.193 eV. The absolute photoionization spectrum was obtained by recording a spectrum at a resolution of 8 meV (50 meV steps) and scaling to the single-energy cross sections. We computed the absolute VUV photoionization spectrum of OH and O( 3 P) using equation-of-motion coupled-cluster Dyson orbitals and a Coulomb photoelectron wave function and found good agreement with the observed absolute photoionization spectra.
Neutron displacement damage cross sections for SiC
Huang Hanchen; Ghoniem, N.
1993-01-01
Calculations of neutron displacement damage cross sections for SiC are presented. We use Biersack and Haggmark's empirical formula in constructing the electronic stopping power, which combines Lindhard's model at low PKA energies and Bethe-Bloch's model at high PKA energies. The electronic stopping power for polyatomic materials is computed on the basis of Bragg's Additivity Rule. A continuous form of the inverse power law potential is used for nuclear scattering. Coupled integro-differential equations for the number of displaced atoms j, caused by PKA i, are then derived. The procedure outlined above gives partial displacement cross sections, displacement cross sections for each specie of the lattice, and for each PKA type. The corresponding damage rates for several fusion and fission neutron spectra are calculated. The stoichiometry of the irradiated material is investigated by finding the ratio of displacements among various atomic species. The role of each specie in displacing atoms is also investigated by calculating the fraction of displacements caused by each PKA type. The study shows that neutron displacement damage rates of SiC in typical magnetic fusion reactor first walls will be ∝10-15 dpa MW -1 m 2 ; in typical lead-protected inertial confinement fusion reactor first walls they will be ∝15-20 dpa MW -1 m 2 . For fission spectra, we find that the neutron displacement damage rate of SiC is ∝74 dpa per 10 27 n/m 2 in FFTF, ∝39 dpa per 10 27 n/m 2 in HFIR, and 25 dpa per 10 27 n/m 2 in NRU. Approximately 80% of displacement atoms are shown to be of the carbon-type. (orig.)
Propionaldehyde infrared cross-sections and band strengths
Köroğlu, Batikan; Loparo, Zachary; Nath, Janardan; Peale, Robert E.; Vasu, Subith S.
2015-01-01
The use of oxygenated biofuels reduces the greenhouse gas emissions; however, they also result in increased toxic aldehyde by-products, mainly formaldehyde, acetaldehyde, acrolein, and propionaldehyde. These aldehydes are carcinogenic and/or toxic and therefore it is important to understand their formation and destruction pathways in combustion and atmospheric systems. Accurate information about their infrared cross-sections and integrated strengths are crucially needed for development of quantitative detection schemes and modeling tools. Critical to the development of such diagnostics are accurate characterization of the absorption features of these species. In this study, the gas phase infrared spectra of propionaldehyde (also called propanal, CH 3 –CH 2 –CHO), a saturated three carbon aldehyde found in the exhaust emissions of biodiesel or diesel fuels, was studied using high resolution Fourier Transform Infrared (FTIR) spectroscopy over the wavenumber range of 750−3300 cm −1 and at room temperature 295 K. The absorption cross sections of propionaldehyde were recorded at resolutions of 0.08 and 0.096 cm −1 and at seven different pressures (4−33 Torr). The calculated band-strengths were reported and the integrated band intensity results were compared with values taken from the Pacific Northwest National Laboratory (PNNL) database (showing less than 2% discrepancy). The peak positions of the 19 different vibrational bands of propionaldehyde were also compared with previous studies taken at a lower resolution of 1 cm −1 . To the best of our knowledge, the current FTIR measurements provide the first highest resolution infrared cross section data for propionaldehyde. - Highlights: • High resolution IR spectra of propionaldehyde were measured by FTIR spectrometer. • The discrepancy between the present study and PNNL database was less than 2%. • The fundamental vibrational frequencies were reported at high resolution. • The rovibrational Q
OSMOSE: An experimental program for the qualification of integral cross sections of actinides
Hudelot, J. P.; Klann, R.; Fougeras, P.; Jorion, F.; Drin, N.; Donnet, L.
2004-01-01
The accurate integral cross sectional reaction rates in representative spectra for the actinides are discussed at OSMOSE program. The first step in obtaining better nuclear data consists of measuring accurate integral data and comparing it to integrated energy dependent data: this comparison provides a direct assessment of the effect of deficiencies in the differential data. The OSMOSE program includes a complete analytical program associated with experimental measurement program and aims at understanding and resolving discrepancies between calculated and measured values. The measurement covers a wide range of neutron spectra, from over-moderate thermal spectra to fast spectra. (authors)
Mechanized evaluation of neutron cross-sections
Horsley, A.; Parker, J.B.
1967-01-01
The evaluation work to provide accurate and consistent neutron cross-section data for multigroup neutronics calculations is not fully exploiting the available theoretical and experimental results; this has been so particularly since the introduction of on-line data handling techniques enabled experimenters to turn out vast quantities of numbers. This situation can be radically improved only by mechanizing the evaluation processes. Systems such as the SC1SRS tape will not only largely overcome the task of collecting data but will provide speedy access to it; by using computers and graph-plotting machines to tabulate and display this data, the labour of evaluation can be very greatly reduced. With some types of cross-section there is hope that by using modern curve-fitting techniques the actual evaluation and statistical accounting of the data can be performed automatically. Some areas where automatic evaluation would seem likely to succeed are specified and a discussion of the mathematical difficulties incurred, such as the elimination of anomalous data, is given. Particularly promising is the use of splines in the mechanized evaluation of data. Splines are the mathematical analogues of the draughtsman's spline used in drawing smooth curves. Their principal properties are the excellent approximations they give to the derivatives of a function; in contrast to conventional polynomial fitting, this feature ensures good interpolation and, when required, stable extrapolation. Various methods of using splines in data graduation and the problem of marrying these methods to standard statistical procedures are examined. The results of work done at AWRE with cubic splines on the mechanized evaluation of neutron scattering total cross-section and angular distribution data are presented. (author)
LEP vacuum chamber, cross-section
CERN PhotoLab
1983-01-01
Cross-section of the final prototype for the LEP vacuum chamber. The elliptic main-opening is for the beam. The small channel to the left is for the cooling water, to carry away the heat deposited by the synchrotron radiation. The square channel to the right houses the Non-Evaporable Getter (NEG) pump. The chamber is made from extruded aluminium. Its outside is clad with lead, to stop the synchrotron radiation emitted by the beam. For good adherence between Pb and Al, the Al chamber was coated with a thin layer of Ni. Ni being slightly magnetic, some resulting problems had to be overcome. See also 8301153.
How to extract cross sections from TDHF
Le Tourneux, Jean
1979-01-01
In spite of all the recent progress in solving numerically TDHF (Time Dependent Hartree-Fock) equations for heavy-ion collisions, this method is still far from lending itself readily to the computation of cross sections, except in the case of fusion. The theory presented here is purely formal so far and would lead to fairly heavy calculations in practice. It solves the problem of channel identification in the outgoing asymptotic region of TDHF solutions. It throws a bridge between TDHF and more traditional theories of nuclear reactions, which are time-independent
Hyperon magnetic moments and total cross sections
Lipkin, H.J.
1982-06-01
The new data on both total cross sections and magnetic moments are simply described by beginning with the additive quark model in an SU(3) limit where all quarks behave like strange quarks and breaking both additivity and SU(3) simultaneously with an additional non-additive mechanism which affects only nonstrange quark contributions. The suggestion that strange quarks behave more simply than nonstrange may provide clues to underlying structure or dynamics. Small discrepancies in the moments are analyzed and shown to provide serious difficulties for most models if they are statistically significant. (author)
Neutron capture cross section of $^{93}$Zr
We propose to measure the neutron capture cross section of the radioactive isotope $^{93}$Zr. This project aims at the substantial improvement of existing results for applications in nuclear astrophysics and emerging nuclear technologies. In particular, the superior quality of the data that can be obtained at n_TOF will allow on one side a better characterization of s-process nucleosynthesis and on the other side a more accurate material balance in systems for transmutation of nuclear waste, given that this radioactive isotope is widely present in fission products.
Fission cross section measurements for minor actinides
Fursov, B. [IPPE, Obninsk (Russian Federation)
1997-03-01
The main task of this work is the measurement of fast neutron induced fission cross section for minor actinides of {sup 238}Pu, {sup 242m}Am, {sup 243,244,245,246,247,248}Cm. The task of the work is to increase the accuracy of data in MeV energy region. Basic experimental method, fissile samples, fission detectors and electronics, track detectors, alpha counting, neutron generation, fission rate measurement, corrections to the data and error analysis are presented in this paper. (author)
Charge changing cross sections of relativistic uranium
Gould, H.; Greiner, D.; Lindstrom, P.; Symons, T.J.M.; Crawford, H.; Thieberger, P.; Wegner, H.
1984-11-01
We report equilibrium charge state distributions of uranium at energies of 962 MeV/nucleon, 437 MeV/nucleon and 200 MeV/nucleon in low Z and high Z targets and the cross sections for U 92+ reversible U 91+ and U 91+ reversible U 90+ at 962 MeV/nucleon and 437 MeV/nucleon. Equilibrium thickness Cu targets produce approx. = 5% bare U 92+ at 200 MeV/nucleon and 85% U 92+ at 962 MeV/nucleon. 7 references, 5 figures
Charge changing cross sections of relativistic uranium
Gould, H; Greiner, D; Lindstrom, P; Symons, T J.M.; Crawford, H; Thieberger, P; Wegner, H
1985-05-15
We report equilibrium charge state distributions of uranium at energies of 962 MeV/nucleon, 437 MeV/nucleon and 200 MeV/nucleon in low Z and high Z targets and the cross sections for U/sup 92 +/reversibleU/sup 91 +/ and U/sup 91 +/reversibleU/sup 90 +/ at 962 MeV/nucleon and 437 MeV/nucleon. Equilibrium thickness Cu targets produce approx.=5% bare U/sup 92 +/ at 200 MeV/nucleon and 85% U/sup 92 +/ at 962 MeV/nucleon.
Measurement of thermal neutron capture cross section
Huang Xiaolong; Han Xiaogang; Yu Weixiang; Lu Hanlin; Zhao Wenrong
2001-01-01
The thermal neutron capture cross sections of 71 Ga(n, γ) 72 Ga, 94 Zr(n, γ) 95 Zr and 191 Ir(n, γ) 192 Ir m1+g,m2 reactions were measured by using activation method and compared with other measured data. Meanwhile the half-life of 72 Ga was also measured. The samples were irradiated with the neutron in the thermal column of heavy water reactor of China Institute of Atomic Energy. The activities of the reaction products were measured by well-calibrated Ge(Li) detector
Empirical continuation of the differential cross section
Borbely, I.
1978-12-01
The theoretical basis as well as the practical methods of empirical continuation of the differential cross section into the nonphysical region of the cos theta variable are discussed. The equivalence of the different methods is proved. A physical applicability condition is given and the published applications are reviewed. In many cases the correctly applied procedure turns out to provide nonsignificant or even incorrect structure information which points to the necessity for careful and statistically complete analysis of the experimental data with a physical understanding of the analysed process. (author)
L-shell photoelectric cross section measurements
Arora, S K; Allawadhi, K L; Sood, B S [Punjabi Univ., Patiala (India). Nuclear Science Labs.
1981-05-14
L-shell photoelectric cross sections in Ta, W, Au, Pb, Th and U at 59.5 keV have been determined using three different versions of Sood's method of measuring the absolute yield of fluorescent x-rays when a target is irradiated with a known flux of photons. The results obtained by all the methods agree with one another showing that no hidden systematic errors are involved in the measurements. The present results are found to compare well with the theoretical calculations of Scofield (Lawrence Livermore Laboratory Report No 51326).
Atlas of photoneutron cross sections obtained with monoenergetic photons
Dietrich, S.S.; Berman, B.L.
1988-01-01
Photoneutron cross-section and integrated cross-section data obtained with monoenergetic photons are presented in a uniform format. All of the measured partial photoneutron cross sections, the total photoneutron cross section, and the photoneutron yield cross section are plotted as functions of the incident photon energy, as are the integrated photoneutron cross sections and their first and second moments. The values of the integrated cross sections and the moments of the integrated total cross section up to the highest photon energy for which they were measured are tabulated, as are the parameters of Lorentz curves fitted to the total photoneutron cross-section data for medium and heavy nuclei (A>50). This compilation is current as of June 1987. copyright 1988 Academic Press, Inc
ZZ SNLRML, Dosimetry Cross-Section Recommendations
1996-01-01
Description of program or function: Format: SAND-II; Number of groups: 640 group SAND-II group structure. Nuclides: Cd, B, Au, S, Ni, Li, F, Na, Mg, Al, Si, P, Sc, Ti, Mn, Fe, Co, Cu, Zn, Zr, Nb, Mo, Rh, Ag, In, I, Th, U, Np, Pu, Am. Origin: ENDF/B-VI, ENDF/B-V, IRDF-90, JENDL-3, JEF 2.2 and GLUCS data with special modifications from private communications. Weighting spectrum: flat. SNLRML is a reactor dosimetry library that draws upon all available evaluated cross section libraries and selects the best evaluation for application to research reactor spectrum determinations. Many of the components of the SNLRML come from the ENDF/B-VI and IRDF-90 (DLC-0161) libraries. The library format was selected for easy interface with spectrum determination codes such as SAND-II (CCC-0112 and LSL-M2 (PSR-233) and the new PSR-0345/SNL/SAND-II has been enhanced to interface with SNLRML. The data is recommended for spectrum determination applications and for the prediction of neutron activation of typical radiation sensor materials. The library has been tested for consistency of the cross section in wide variety of neutron environments. The results and cautions from this testing have been documented. The data has been interfaced with radiation transport codes, such as TWODANT-SYS (CCC-0547) and MCNP (CCC-0200), in order to compare calculated and measured activities for benchmark reactor experiments
Pion production cross sections and associated parameters
Bradbury, J.N.
1985-01-01
Negative pions have been used for radiotherapy at the meson factories LAMPF (USA), SIN (Switzerland), and TRIUMF (Canada) and have been planned for use at new meson facilities under construction (USSR) and at proposed dedicated medical facilities. Providing therapeutically useful dose rates of pions requires a knowledge of the pion production cross sections as a function of primary proton energy (500 to 1000 MeV), pion energy (less than or equal to100 MeV), production angle, and target material. The current status of the data base in this area is presented including theoretical guidelines for extrapolation purposes. The target material and geometry, as well as the proton and pion beam parameters, will affect the electron (and muon) contamination in the beam which may have an important effect on both the LET characteristics of the dose and the dose distribution. In addition to cross-section data, channel characteristics such as length of pion trajectory, solid-angle acceptance, and momentum analysis will affect dose rate, distribution, and quality. Such considerations are briefly addressed in terms of existing facilities and proposed systems. 16 refs., 6 figs
Mid-IR Absorption Cross-Section Measurements of Hydrocarbons
Alrefae, Majed Abdullah
2013-05-01
Laser diagnostics are fast-response, non-intrusive and species-specific tools perfectly applicable for studying combustion processes. Quantitative measurements of species concentration and temperature require spectroscopic data to be well-known at combustion-relevant conditions. Absorption cross-section is an important spectroscopic quantity and has direct relation to the species concentration. In this work, the absorption cross-sections of basic hydrocarbons are measured using Fourier Transform Infrared (FTIR) spectrometer, tunable Difference Frequency Generation laser and fixed wavelength helium-neon laser. The studied species are methane, methanol, acetylene, ethylene, ethane, ethanol, propylene, propane, 1-butene, n-butane, n-pentane, n-hexane, and n-heptane. The Fourier Transform Infrared (FTIR) spectrometer is used for the measurements of the absorption cross-sections and the integrated band intensities of the 13 hydrocarbons. The spectral region of the spectra is 2800 – 3400 cm-1 (2.9 – 3.6 μm) and the temperature range is 673 – 1100 K. These valuable data provide huge opportunities to select interference-free wavelengths for measuring time-histories of a specific species in a shock tube or other combustion systems. Such measurements can allow developing/improving chemical kinetics mechanisms by experimentally determining reaction rates. The Difference Frequency Generation (DFG) laser is a narrow line-width, tunable laser in the 3.35 – 3.53 μm wavelength region which contains strong absorption features for most hydrocarbons due to the fundamental C-H vibrating stretch. The absorption cross-sections of propylene are measured at seven different wavelengths using the DFG laser. The temperature range is 296 – 460 K which is reached using a Reflex Cell. The DFG laser is very attractive for kinetic studies in the shock tube because of its fast time response and the potential possibility of making species-specific measurements. The Fixed wavelength
Pronyaev, V.; Carlson, A.D.; Capote Noy, R.; Wallner, A.
2011-03-01
The meeting participants have considered the progress in the measurement and evaluation of neutron cross sections and spectra which can be used as standard or reference data. This includes extension of the 197 Au(n,γ) standard to the energy range below 200 keV, 235 U(n th ,f) prompt fission neutron spectrum and neutron induced gamma-production cross sections. The work on this data development project for next two years has been agreed. (author)
Differences between LASL- and ANL-processed cross sections
Kidman, R.B.; MacFarlane, R.E.; Becker, M.
1978-03-01
As part of the Los Alamos Scientific Laboratory (LASL) cross-section processing development, LASL cross sections and results from MINX/1DX system are compared to the Argonne National Laboratory cross sections and results from the ETOE-2/MC 2 -2 system for a simple reactor problem. Exact perturbation theory is used to establish the eigenvalue effect of every isotope group cross-section difference. Cross sections, cross-section differences, and their eigenvalue effects are clearly and conveniently displayed and compared on a group-by-group basis
Cross section homogenization analysis for a simplified Candu reactor
Pounders, Justin; Rahnema, Farzad; Mosher, Scott; Serghiuta, Dumitru; Turinsky, Paul; Sarsour, Hisham
2008-01-01
The effect of using zero current (infinite medium) boundary conditions to generate bundle homogenized cross sections for a stylized half-core Candu reactor problem is examined. Homogenized cross section from infinite medium lattice calculations are compared with cross sections homogenized using the exact flux from the reference core environment. The impact of these cross section differences is quantified by generating nodal diffusion theory solutions with both sets of cross sections. It is shown that the infinite medium spatial approximation is not negligible, and that ignoring the impact of the heterogeneous core environment on cross section homogenization leads to increased errors, particularly near control elements and the core periphery. (authors)
FIZCON, ENDF/B Cross-Sections Redundancy Check
Dunford, Charles L.
2007-01-01
1 - Description of program or function: FIZCON is a program for checking that an evaluated data file has valid data and conforms to recommended procedures. Version 7.01 (April 2005): set success flag after return from beginning; fixed valid level check for an isomer; fixed subsection energy range test in ckf9; changed lower limit on potential scattering test; fixed error in j-value test when l=0 and i=0; added one more significant figure to union grid check and sum up output messages; partial fission cross sections mt=19,20,21 and 38 did not require secondary energy distributions in file 5; corrected product test for elastic scattering; moved potential scattering test to psyche. Version 7.02 (May 2005): Fixed resonance parameter sum test. 2 - Method of solution: FIZCON can recognise the difference between ENDF-6 and ENDF-5 formats and performs its tests accordingly. Some of the tests performed include: data arrays are in increasing energy order; resonance parameter widths add up to the total; Q-values are reasonable and consistent; no required sections are missing and all cover the proper energy range; secondary distributions are normalized to 1.0; energy conservation in decay spectra. Optional tests can be performed to check the redundant cross sections, and algorithms can be used to check for possible incorrect entry of data values (Deviant Point test)
K sup + nucleus total cross sections
Sawafta, R.
1990-01-01
The scattering of K{sup +} mesons from nuclei has attracted considerable interest in the last few years. The K{sup +} holds a very special position as the weakest of all strongly interaction probes. The average cross section is not larger than about 10 mb at lab momenta below 800 MeV/c, corresponding to a mean free path in the nucleus larger than 5 fm. Thus the K{sup +} is capable of probing the entire volume of the nucleus. Single scattering of the K{sup +} with a nucleon in the nucleus dominates the nuclear scattering, and only small and calculable higher order corrections are needed. The nucleon is a dynamical entity and its internal structure can, in principle, be altered by its surrounding nuclear environment. This work reports an experiment in which the K{sup +} is used to compare the nucleon in the nucleus with a free nucleon.
Differential cross section of atomic hydrogen photoionization
Kondratovich, V.D.; Ostrovskij, V.N.
1986-01-01
Differential cross-section of atomic hydrogen photoeffect in external electric field was investigated in semiclassical approximation. Interference was described. It occurred due to the fact that infinite number of photoelectron trajectories leads to any point of classically accessible motion region. Interference picture can reach macroscopic sizes. The picture is determined by location of function nodes, describing finite electron motion along one of parabolic coordinates. The squares of external picture rings are determined only by electric field intensity in the general case at rather high energies. Quantum expression for photocurrent density was obtained using Green function in superposition of Coulomb and uniform field as well as semiclassical approximation. Possible applications of macroscopic interference picture to specification of atom ionization potentials, selective detection of atoms or particular molecules, as well as weak magnetic field and observation of Aaronov-Bom effect are discussed
Angle-averaged Compton cross sections
Nickel, G.H.
1983-01-01
The scattering of a photon by an individual free electron is characterized by six quantities: α = initial photon energy in units of m 0 c 2 ; α/sub s/ = scattered photon energy in units of m 0 c 2 ; β = initial electron velocity in units of c; phi = angle between photon direction and electron direction in the laboratory frame (LF); theta = polar angle change due to Compton scattering, measured in the electron rest frame (ERF); and tau = azimuthal angle change in the ERF. We present an analytic expression for the average of the Compton cross section over phi, theta, and tau. The lowest order approximation to this equation is reasonably accurate for photons and electrons with energies of many keV
Plasma-based radar cross section reduction
Singh, Hema; Jha, Rakesh Mohan
2016-01-01
This book presents a comprehensive review of plasma-based stealth, covering the basics, methods, parametric analysis, and challenges towards the realization of the idea. The concealment of aircraft from radar sources, or stealth, is achieved through shaping, radar absorbing coatings, engineered materials, or plasma, etc. Plasma-based stealth is a radar cross section (RCS) reduction technique associated with the reflection and absorption of incident electromagnetic (EM) waves by the plasma layer surrounding the structure. A plasma cloud covering the aircraft may give rise to other signatures such as thermal, acoustic, infrared, or visual. Thus it is a matter of concern that the RCS reduction by plasma enhances its detectability due to other signatures. This needs a careful approach towards the plasma generation and its EM wave interaction. The book starts with the basics of EM wave interactions with plasma, briefly discuss the methods used to analyze the propagation characteristics of plasma, and its generatio...
ISSUES IN NEUTRON CROSS SECTION COVARIANCES
Mattoon, C.M.; Oblozinsky,P.
2010-04-30
We review neutron cross section covariances in both the resonance and fast neutron regions with the goal to identify existing issues in evaluation methods and their impact on covariances. We also outline ideas for suitable covariance quality assurance procedures.We show that the topic of covariance data remains controversial, the evaluation methodologies are not fully established and covariances produced by different approaches have unacceptable spread. The main controversy is in very low uncertainties generated by rigorous evaluation methods and much larger uncertainties based on simple estimates from experimental data. Since the evaluators tend to trust the former, while the users tend to trust the latter, this controversy has considerable practical implications. Dedicated effort is needed to arrive at covariance evaluation methods that would resolve this issue and produce results accepted internationally both by evaluators and users.
Partial cross sections in H- photodetachment
Halka, M.
1993-04-01
This dissertation reports experimental measurements of partial decay cross sections in the H - photodetachment spectrum. Observed decays of the 1 P 0 H -** (n) doubly-excitedresonances to the H(N=2) continuum are reported for n=2,3, and 4 from 1990 runs in which the author participated. A recent analysis of 1989 data revealing effects of static electric fields on the partial decay spectrum above 13.5 eV is also presented. The experiments were performed at the High Resolution Atomic Beam Facility. the Los Alamos Meson Physics Facility, with a relativistic H - beam (β=0.842)intersecting a ND:YAG laser. Variation of the intersection angle amounts to Doppler-shifting the photon energy, allowing continuous tuning of the laser energy as viewed from the moving ions' frame
Angle-averaged Compton cross sections
Nickel, G.H.
1983-01-01
The scattering of a photon by an individual free electron is characterized by six quantities: ..cap alpha.. = initial photon energy in units of m/sub 0/c/sup 2/; ..cap alpha../sub s/ = scattered photon energy in units of m/sub 0/c/sup 2/; ..beta.. = initial electron velocity in units of c; phi = angle between photon direction and electron direction in the laboratory frame (LF); theta = polar angle change due to Compton scattering, measured in the electron rest frame (ERF); and tau = azimuthal angle change in the ERF. We present an analytic expression for the average of the Compton cross section over phi, theta, and tau. The lowest order approximation to this equation is reasonably accurate for photons and electrons with energies of many keV.
Sudakov resummation of multiparton QCD cross sections
Bonciani, R; Mangano, Michelangelo L; Nason, P
2003-01-01
We present the general expressions for the resummation, up to next-to-leading logarithmic accuracy, of Sudakov-type logarithms in processes with an arbirtrary number of hard-scattering partons. These results document the formulae used by the authors in several previous phenomenological studies. The resummation formulae presented here, which are valid for phase-space factorizable observables, determine the resummation correction in a process-independent fashion. All process dependence is encoded in the colour and flavour structure of the leading order and virtual one-loop amplitudes, and in Sudakov weights associated to the cross section kinematics. We explicitly illustrate the application to the case of Drell--Yan and prompt-photon production.
Sudakov resummation of multiparton QCD cross sections
Bonciani, Roberto; Catani, Stefano; Mangano, Michelangelo L.; Nason, Paolo
2003-01-01
We present the general expressions for the resummation, up to next-to-leading logarithmic accuracy, of Sudakov-type logarithms in processes with an arbitrary number of hard-scattering partons. These results document the formulae used by the authors in several previous phenomenological studies. The resummation formulae presented here, which are valid for phase-space factorizable observables, determine the resummation correction in a process-independent fashion. All process dependence is encoded in the colour and flavour structure of the leading order and virtual one-loop amplitudes, and in Sudakov weights associated to the cross section kinematics. We explicitly illustrate the application to the case of Drell-Yan and prompt-photon production
Electroweak Boson Cross-Section Measurements
The ATLAS collaboration
2009-01-01
This report summarises the ATLAS prospects for the measurement of W and Z pro- duction cross-section at the LHC. The electron and muon decay channels are considered. Focusing on the early data taking phase, strategies are presented that allow a fast and robust extraction of the signals. An overall uncertainty of about 5% can be achieved with 50 pb−1 in the W channels, where the background uncertainty dominates (the luminosity measurement uncertainty is not discussed here). In the Z channels, the expected preci- sion is 3%, the main contribution coming from the lepton selection efﬁciency uncertainty. Extrapolating to 1 fb−1 , the uncertainties shrink to incompressible values of 1-2%, de- pending on the ﬁnal state. This irreducible uncertainty is essentially driven by strong interaction effects, notably parton distribution uncertainties and non-perturbative effects, affecting the W and Z rapidity and transverse momentum distributions. These effects can be constrained by measuring these distributions. Al...
Reaction cross section for Ne isotopes
Panda, R.N.; Sahu, B.K.; Patra, S.K.
2012-01-01
In the present contribution, first the bulk properties are calculated, such as binding energy (BE), root mean square charge radius r ch , matter radius r m and quadrupole deformation parameter β 2 for 18-32 Ne isotopes in the Relativistic mean field (RMF) and effective field theory motivated RMF (E-RMF) formalisms . Then the total nuclear reaction cross section σR is analyzes for the scattering of 20 Ne and 28-32 Ne from a 12 C target at 240 MeV/nucleon by using the RMF model. Thus the objective of the present study is to calculate the bulk properties as well as a systematic analysis of σR over a range of neutron rich nuclei in the frame work of Glauber model
Topological supersymmetric structure of hadron cross sections
Gauron, P.; Nicolescu, B.; Ouvry, S.
1980-12-01
Recently a way of fully implementing unitarity in the framework of a Dual Topological Unitarization theory, including not only mesons but also baryons, was found. This theory consists in the topological description of hadron interactions involving confined quarks in terms of two 2-dimensional surfaces (a closed 'quantum' surface and a bounded 'classical' surface). We show that this description directly leads, at the zeroth order of the topological expansion, to certain relations between hadron cross-sections, in nice agreement with experimental data. A new topological suppression mechanism is shown to play an important dynamical role. We also point out a new topological supersymmetry property, which leads to realistic experimental consequences. A possible topological origin of the rho and ω universality relations emerges as a by-product of our study
Neutron scattering cross sections of uranium-238
Beghian, L.E.; Kegel, G.H.R.; Marcella, T.V.; Barnes, B.K.; Couchell, G.P.; Egan, J.J.; Mittler, A.; Pullen, D.J.; Schier, W.A.
1979-01-01
The University of Lowell high-resolution time-of-flight spectrometer was used to measure angular distributions and 90-deg excitation functions for neutrons scattered from 238 U in the energy range from 0.9 to 3.1 MeV. This study was limited to the elastic and the first two inelastic groups, corresponding to states of 238 U at 45 keV (2 + ) and 148 keV (4 + ). Angular distributions were measured at primary neutron energies of 1.1, 1.9, 2.5, and 3.1 MeV for the same three neutron groups. Whereas the elastic data are in fair agreement with the evaluation in the ENDF/B-IV file, there is substantial disagreement between the inelastic measurements and the evaluated cross sections. 12 figures
Fission cross-section normalization problems
Wagemans, C.; Ghent Rijksuniversiteit; Deruytter, A.J.
1983-01-01
The present measurements yield σsub(f)-data in the neutron energy from 20 MeV to 30 keV directly normalized in the thermal region. In the keV-region these data are consistent with the absolute σsub(f)-measurements of Szabo and Marquette. For the secondary normalization integral I 2 values have been obtained in agreement with those of Gwin et al. and Czirr et al. which were also directly normalized in the thermal region. For the I 1 integral, however, puzzling low values have been obtained. This was also the case for σsub(f)-bar in neutron energy intervals containing strong resonances. Three additional measurements are planned to further investigate these observations: (i) maintaining the actual approx.2π-geometry but using a 10 B-foil for the neutron flux detection (ii) using a low detection geometry with a 10 B- as well as a 6 Li-flux monitor. Only after these measurements definite conclusions on the I 1 and I 2 integrals can be formulated and final σsub(f)-bar-values can be released. The present study also gives some evidence for a correlation between the integral I 2 and the neutron flux monitor used. The influence of a normalization via I 1 or I 2 on the final cross-section has been shown. The magnitude of possible normalization errors is illustrated. Finally, since 235 U is expected to be an ''easy'' nucleus (low α-activity high σsub(f)-values), there are some indications that the important discrepancies still present in 235 U(n,f) cross-section measurements might partially be due to errors in the neutron flux determination
Photoionization cross-sections of ground and excited valence levels of actinides
Yarzhemsky Victor G.
2012-01-01
Full Text Available The photoionization cross-sections of ground and excited atomic states of actinide atoms were calculated by the Dirac-Fock-Slater method for two excitation energies of X-ray radiation (1253.6 eV and 1486.6 eV. These data are required for calculations of intensities of X-ray photoelectron spectra of actinide compound valence bands and interpretation of experimental spectra.
Picconi, David; Grebenshchikov, Sergy Yu., E-mail: Sergy.Grebenshchikov@ch.tum.de
2016-12-20
This paper relates the partial cross section of a continuous optical emission into a given scattering channel of the lower electronic state to the photofragment population. This allows one to infer partial emission cross sections ‘non-optically’ from product state distributions; in computations, explicit construction of exact scattering states is therefore avoided. Applications to the emission spectra of NaI, CO{sub 2}, and pyrrole are given. It is also demonstrated that a similar relationship holds between partial cross sections of dissociative photoionization and distributions of ionic fragments over final product channels.
Remarks on the comparison of cross section libraries for neutron metrology
Zijp, W.L.; Nolthenius, H.J.; Appelman, K.H.
1977-01-01
Cross section libraries in a 620 group structure were available from different origin: CCC-112B, DETAN-74 and ENDF/B-IV. For a few well known neutron spectra (CFRMF spectrum, ΣΣ spectrum, fission neutron spectrum, HFR neutron spectrum) a comparison was made of the available experimental reaction rates in foil detectors and the reaction rates as calculated with the different cross section libraries. This investigation is dealing with the consistency of cross section data within a library, and the consistency of activity data in actual reaction rate determinations. Some preliminary conclusions are given
Binary and tertiary neutron induced reaction cross sections of chromium and iron
Garg, S.B.
1989-01-01
Investigation has been carried out for the following binary and tertiary reaction cross-sections of Cr-52 and Fe-56: (n,p), (n,pn), (n,np), (n,α), (n, nα), (n, 2n) and (n, 3n), energy spectra of the emitted neutron, proton, α-particle and γ-rays, angle-energy correlated double differential cross-sections for the secondary emitted neutrons and total production cross-sections for neutron, hydrogen, helium and gamma-rays. 12 refs, 20 figs, 1 tab
Thermal neutron capture cross section for the K isomer 177Lum
Belier, G.; Roig, O.; Daugas, J.-M.; Giarmana, O.; Meot, V.; Letourneau, A.; Marie, F.; Foucher, Y.; Aupiais, J.; Abt, D.; Jutier, Ch.; Le Petit, G.; Bettoni, C.; Gaudry, A.; Veyssiere, Ch.; Barat, E.; Dautremer, T.; Trama, J.-Ch.
2006-01-01
The thermal neutron radiative capture cross section for the K isomeric state in 177 Lu has been measured for the first time. Several 177 Lu m targets have been prepared and irradiated in various neutron fluxes at the Lauee Langevin Institute in Grenoble and at the CEA reactors OSIRIS and ORPHEE in Saclay. The method consists of measuring the 178 Lu activity by γ-ray spectroscopy. The values obtained in four different neutron spectra have been used to calculate the resonance integral of the radiative capture cross section for 177 Lu m . In addition, an indirect method leads to the determination of the 177 Lu g neutron radiative capture cross section
Electron capture cross sections by O+ from atomic He
Joseph, Dwayne C; Saha, Bidhan C
2009-01-01
The adiabatic representation is used in both the quantal and semi classical molecular orbital close coupling methods (MOCC) to evaluate charge exchange cross sections. Our results show good agreement with experimental cross sections
Electron capture cross sections by O+ from atomic He
Joseph, Dwayne C.; Saha, Bidhan C.
2009-11-01
The adiabatic representation is used in both the quantal and semi classical molecular orbital close coupling methods (MOCC) to evaluate charge exchange cross sections. Our results show good agreement with experimental cross sections
Single-level resonance parameters fit nuclear cross-sections
Drawbaugh, D. W.; Gibson, G.; Miller, M.; Page, S. L.
1970-01-01
Least squares analyses of experimental differential cross-section data for the U-235 nucleus have yielded single level Breit-Wigner resonance parameters that fit, simultaneously, three nuclear cross sections of capture, fission, and total.
Total and ionization cross sections of electron scattering by fluorocarbons
Antony, B K; Joshipura, K N; Mason, N J
2005-01-01
Electron impact total cross sections (50-2000 eV) and total ionization cross sections (threshold to 2000 eV) are calculated for typical plasma etching molecules CF 4 , C 2 F 4 , C 2 F 6 , C 3 F 8 and CF 3 I and the CF x (x 1-3) radicals. The total elastic and inelastic cross sections are determined in the spherical complex potential formalism. The sum of the two gives the total cross section and the total inelastic cross section is used to calculate the total ionization cross sections. The present total and ionization cross sections are found to be consistent with other theories and experimental measurements, where they exist. Our total cross section results for CF x (x = 1-3) radicals presented here are first estimates on these species
Mid-IR Absorption Cross-Section Measurements of Hydrocarbons
Alrefae, Majed Abdullah
2013-01-01
-known at combustion-relevant conditions. Absorption cross-section is an important spectroscopic quantity and has direct relation to the species concentration. In this work, the absorption cross-sections of basic hydrocarbons are measured using Fourier Transform
Machacek, J. R. [Atomic and Molecular Physics Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra 2601 (Australia); Mahapatra, D. P. [Department of Physics, Utkal University, Bhubaneswar 751004 (India); Schultz, D. R. [Department of Physics, Univ. of North Texas, Denton, TX 76203 (United States); Ralchenko, Yu. [Atomic Spectroscopy Group, National Institute of Standards and Technology, Gaithersburg, MD 20899-8422 (United States); Moradmand, A.; El Ghazaly, M. O. A.; Chutjian, A. [Astrophysics and Space Sciences Section, Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109 (United States)
2015-08-10
Relevant to modeling and understanding X-ray emission from cometary and planetary atmospheres, total cross-sections for 1.17 and 2.33 keV/u O{sup 6+} colliding with H{sub 2}O, CO, CO{sub 2}, CH{sub 4}, N{sub 2}, NO, N{sub 2}O, and Ar have been measured for the processes of single, double, and triple charge exchanges. Using these measurements as benchmarks, synthetic emission spectra spanning the X-ray, UV, and visible range have been calculated based on theoretical treatment of the transfer of between one and six electrons from the target neutrals to the projectile ion, followed by radiative and non-radiative decay of the highly excited states produced in these collisions. The results help add to the base of knowledge required to simulate ion-neutral processes in astrophysical environments; refine the present understanding of these fundamental atomic processes; and guide future observations, laboratory measurements, and theoretical predictions.
Photoionization cross section of atomic and molecular oxygen
Pareek, P.N.
1983-01-01
Photoionization cross sections of atomic oxygen and dissociative photoionization cross sections of molecular oxygen were measured from their respective thresholds to 120 angstrom by use of a photoionization mass spectrometer in conjunction with a spark light source. The photoionization cross sections O 2 + parent ion and O + fragment ion from neutral O 2 were obtained by a technique that eliminated the serious problem of identifying the true abundances of O + ions. These ions are generally formed with considerable kinetic energy and, because most mass spectrometers discriminate against energetic ions, true O + abundances are difficult to obtain. In the present work the relative cross sections for producing O + ions are obtained and normalized against the total cross sections in a spectral region where dissociative ionization is not possible. The fragmentation cross sections for O + were then obtained by subtraction of O 2 + cross sections from the known total photoionization cross sections. The results are compared with the previously published measurements. The absolute photoionization cross section of atomic oxygen sigma 8 /sub +/ was measured at 304 A. The actual number density of oxygen atoms within the ionization region was obtained by measuring the fraction of 0 2 molecules dissociated. This sigma/sub +/ at 304 angstrom was used to convert the relative photoinization cross sections, measured as a function of wavelength using a calibrated photodiode, to absolute cross sections. The results are compared with previous measurements and calculated cross sections. angstrom Rydberg series converging to the OII 4 P state was observed
Multilevel parametrization of fissile nuclei resonance cross sections
Lukyanov, A.A.; Kolesov, V.V.; Janeva, N.
1987-01-01
Because the resonance interference has an important influence on the resonance structure of neutron cross sections energy dependence at lowest energies, multilevel scheme of the cross section parametrization which take into account the resonance interference is used for the description with the same provisions in the regions of the interferential maximum and minimum of the resonance cross sections of the fissile nuclei
Propionaldehyde infrared cross-sections and band strengths
Köroğlu, Batikan; Loparo, Zachary; Nath, Janardan; Peale, Robert E.; Vasu, Subith S.
2015-02-01
The use of oxygenated biofuels reduces the greenhouse gas emissions; however, they also result in increased toxic aldehyde by-products, mainly formaldehyde, acetaldehyde, acrolein, and propionaldehyde. These aldehydes are carcinogenic and/or toxic and therefore it is important to understand their formation and destruction pathways in combustion and atmospheric systems. Accurate information about their infrared cross-sections and integrated strengths are crucially needed for development of quantitative detection schemes and modeling tools. Critical to the development of such diagnostics are accurate characterization of the absorption features of these species. In this study, the gas phase infrared spectra of propionaldehyde (also called propanal, CH3-CH2-CHO), a saturated three carbon aldehyde found in the exhaust emissions of biodiesel or diesel fuels, was studied using high resolution Fourier Transform Infrared (FTIR) spectroscopy over the wavenumber range of 750-3300 cm-1 and at room temperature 295 K. The absorption cross sections of propionaldehyde were recorded at resolutions of 0.08 and 0.096 cm-1 and at seven different pressures (4-33 Torr). The calculated band-strengths were reported and the integrated band intensity results were compared with values taken from the Pacific Northwest National Laboratory (PNNL) database (showing less than 2% discrepancy). The peak positions of the 19 different vibrational bands of propionaldehyde were also compared with previous studies taken at a lower resolution of 1 cm-1. To the best of our knowledge, the current FTIR measurements provide the first highest resolution infrared cross section data for propionaldehyde.
Comparison of integral cross section values of several cross section libraries in the SAND-II format
Zijp, W.L.; Nolthenius, H.J.
1978-01-01
A comparison of some integral cross section values for several cross section libraries in the SAND-II format is presented. The integral cross section values are calculated with aid of the spectrum functions for a Watt fission spectrum, a 1/E spectrum and a Maxwellian spectrum. The libraries which are considered here are CCC-112B, ENDF/B-IV, DETAN74, LAPENAS and CESNEF. These 5 cross section libraries used have all the SAND-II format. (author)
Relaxation and cross section effects in valence band photoemission spectroscopy
McFeely, F.R.
1976-09-01
Various problems relating to the interpretation of valence band x-ray photoemission (XPS) spectra of solids are discussed. The experiments and calculations reported herein deal with the following questions: (1) To what extent do many-body effects manifest themselves in an XPS valence band spectrum, and thus invalidate a direct comparison between the photoemission energy distribution, I(E), and the density of states, N(E), calculated on the basis of ground-state one-electron theory. (2) The effect of the binding-energy-dependent photoemission cross section on I(E) at XPS energies. (3) In favorable cases indicated by (1) and (2) we examine the effect of the interaction of the crystal field with the apparent spin-orbit splittings of core levels observed in XPS spectra. (4) The use of tight binding band structure calculations to parameterize the electronic band structure from XPS and other data is described. (5) The use of high energy angle-resolved photoemission on oriented single crystals to gain orbital symmetry information is discussed. (6) The evolution of the shape of the photoemission energy distribution (of polycrystalline Cu) as a function of photon energy from 50 less than or equal h ω less than or equal 175 is discussed
The Effects of Spherical Surface and Laser Polarization on the Photodetachment Cross Section of H−
Haneef Muhammad; Arif Suneela; Akbar Jehan; Shamim Aneela; Shah Nasrullah; Zahir Muhammad; Ullah Hameed
2013-01-01
We report the combined effects of laser polarization and curvature of the spherical surface on the detached electron spectra from H − . The Theoretical imaging method is used as a tool of investigation. The photodetachment cross sections for various polarization angles, radii of curvatures and inter ion surface distances are displayed. The analysis of the spectra reveals that the laser polarization angle θ L , curvature of the surface r c and inter ion surface distance d strongly affect oscillations in the spectra. Therefore, a fine control on the laser polarization and that of curvature in the surface can be used to control oscillations in the photodetachment of negative ions. (atomic and molecular physics)
Soran, P.D.; Seamon, R.E.
1980-05-01
Graphs of all neutron cross sections and photon production cross sections on the Recommended Monte Carlo Cross Section (RMCCS) library have been plotted along with local neutron heating numbers. Values for anti ν, the average number of neutrons per fission, are also given
Seamon, R.E.; Soran, P.D.
1980-06-01
Graphs of all neutron cross sections and photon production cross sections on the Alternate Monte Carlo Cross Section (AMCCS) library have been plotted along with local neutron heating numbers. The values of ν-bar, the average number of neutrons per fission, are also plotted for appropriate isotopes
[Fast neutron cross section measurements]: Progress report
1988-01-01
As projected in our previous proposal, the past year on the cross section project at the University of Michigan has been one primarily of construction and assembly of our 14 MeV pulsed Neutron Facility. All the components of the system have now been either purchased or fabricated in our shop facilities and have been assembled in their final configuration. We are now in the process of testing the rf components that have been designed to deliver voltage to both the pulser and buncher stages. We expect that the system will be operational by the end of the current contract year. We have also accomplished the design and construction of several other major pieces of equipment that are needed to begin fast neutron time-of-flight measurements. These include the primary proton recoil detector, and a californium fission chamber needed in the efficiency calibration of the primary detector. We have also added considerable concrete shielding designed to lower the neutron background in the experimental area. 10 figs., 5 tabs
Neutron cross section measurements at ORELA
Dabbs, J.W.T.
1979-01-01
ORELA (Oak Ridge Electron Linear Accelerator) has been for the last decade the most powerful and useful pulsed neutron time-of-flight facility in the world, particularly in the broad midrange of neutron energies (10 eV to 1 MeV). This position will be enhanced with the addition of a pulse narrowing prebuncher, recently installed and now under test. Neutron capture, fission, scattering, and total cross sections are measured by members of the Physics and Engineering Physics Divisions of ORNL, and by numerous guests and visitors. Several fundamental and applied measurements are described, with some emphasis on instrumentation used. The facility comprises the accelerator and its target(s), 10 evacuated neutron flight paths having 18 measurement stations at flight path distances 8.9 to 200 meters, and a complex 4-computer data acquisition system capable of handling some 17,000 32-bit events/s from a total of 12 data input ports. The system provides a total of 2.08 x 10 6 words of data storage on 3 fast disk units. In addition, a dedicated PDP-10 timesharing system with a 250-megabyte disk system and 4 PDP-15 graphic display satellites permits on-site data reduction and analysis. More than 10 man-years of application software development supports the system, which is used directly by individual experiments. 12 figures, 1 table
Resonance capture cross section of 207Pb
Domingo-Pardo, C.; Aerts, G.; Alvarez-Pol, H.; Alvarez-Velarde, F.; Andriamonje, S.; Andrzejewski, J.; Assimakopoulos, P.; Audouin, L.; Badurek, G.; Baumann, P.; Becvar, F.; Berthoumieux, E.; Bisterzo, S.; Calvino, F.; Cano-Ott, D.; Capote, R.; Carrapico, C.; Cennini, P.; Chepel, V.; Chiaveri, E.; Colonna, N.; Cortes, G.; Couture, A.; Cox, J.; Dahlfors, M.; David, S.; Dillman, I.; Dolfini, R.; Dridi, W.; Duran, I.; Eleftheriadis, C.; Embid-Segura, M.; Ferrant, L.; Ferrari, A.; Ferreira-Marques, R.; Fitzpatrick, L.; Frais-Koelbl, H.; Fujii, K.; Furman, W.; Gallino, R.; Goncalves, I.; Gonzalez-Romero, E.; Goverdovski, A.; Gramegna, F.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Haas, B.; Haight, R.; Heil, M.; Herrera-Martinez, A.; Igashira, M.; Isaev, S.; Jericha, E.; Kadi, Y.; Kappeler, F.; Karamanis, D.; Karadimos, D.; Kerveno, M.; Ketlerov, V.; Koehler, P.; Konovalov, V.; Kossionides, E.; Krticka, M.; Lamboudis, C.; Leeb, H.; Lindote, A.; Lopes, I.; Lozano, M.; Lukic, S.; Marganiec, J.; Marrone, S.; Mastinu, P.; Mengoni, A.; Milazzo, P.M.; Moreau, C.; Mosconi, M.; Neves, F.; Oberhummer, H.; Oshima, M.; O'Brien, S.; Pancin, J.; Papachristodoulou, C.; Papadopoulos, C.; Paradela, C.; Patronis, N.; Pavlik, A.; Pavlopoulos, P.; Perrot, L.; Plag, R.; Plompen, A.; Plukis, A.; Poch, A.; Pretel, C.; Quesada, J.; Rauscher, T.; Reifarth, R.; Rosetti, M.; Rubbia, C.; Rudolf, G.; Rullhusen, P.; Salgado, J.; Sarchiapone, L.; Savvidis, I.; Stephan, C.; Tagliente, G.; Tain, J.L.; Tassan-Got, L.; Tavora, L.; Terlizzi, R.; Vannini, G.; Vaz, P.; Ventura, A.; Villamarin, D.; Vincente, M.C.; Vlachoudis, V.; Vlastou, R.; Voss, F.; Walter, S.; Wendler, H.; Wiescher, M.; Wisshak, K.
2006-01-01
The radiative neutron capture cross section of 207Pb has been measured at the CERN neutron time of flight installation n_TOF using the pulse height weighting technique in the resolved energy region. The measurement has been performed with an optimized setup of two C6D6 scintillation detectors, which allowed us to reduce scattered neutron backgrounds down to a negligible level. Resonance parameters and radiative kernels have been determined for 16 resonances by means of an R-matrix analysis in the neutron energy range from 3 keV to 320 keV. Good agreement with previous measurements was found at low neutron energies, whereas substantial discrepancies appear beyond 45 keV. With the present results, we obtain an s-process contribution of 77(8)% to the solar abundance of 207Pb. This corresponds to an r-process component of 23(8)%, which is important for deriving the U/Th ages of metal poor halo stars.
Josephson cross-sectional model experiment
Ketchen, M.B.; Herrell, D.J.; Anderson, C.J.
1985-01-01
This paper describes the electrical design and evaluation of the Josephson cross-sectional model (CSM) experiment. The experiment served as a test vehicle to verify the operation at liquid-helium temperatures of Josephson circuits integrated in a package environment suitable for high-performance digital applications. The CSM consisted of four circuit chips assembled on two cards in a three-dimensional card-on-board package. The chips (package) were fabricated in a 2.5-μm (5-μm) minimum linewidth Pb-alloy technology. A hierarchy of solder and pluggable connectors was used to attach the parts together and to provide electrical interconnections between parts. A data path which simulated a jump control sequence and a cache access in each machine cycle was successfully operated with cycle times down to 3.7 ns. The CSM incorporated the key components of the logic, power, and package of a prototype Josephson signal processor and demonstrated the feasibility of making such a processor with a sub-4-ns cycle time
Female medical leadership: cross sectional study.
Kvaerner, K J; Aasland, O G; Botten, G S
1999-01-09
To assess the relation between male and female medical leadership. Cross sectional study on predictive factors for female medical leadership with data on sex, age, specialty, and occupational status of Norwegian physicians. Oslo, Norway. 13 844 non-retired Norwegian physicians. Medical leaders, defined as physicians holding a leading position in hospital medicine, public health, academic medicine, or private health care. 14.6% (95% confidence interval 14.0% to 15.4%) of the men were leaders compared with 5.1% (4.4% to 5.9%) of the women. Adjusted for age men had a higher estimated probability of leadership in all categories of age and job, the highest being in academic medicine with 0.57 (0.42 to 0.72) for men aged over 54 years compared with 0.39 (0.21 to 0.63) for women in the same category. Among female hospital physicians there was a positive relation between the proportion of women in their specialty and the probability of leadership. Women do not reach senior positions as easily as men. Medical specialties with high proportions of women have more female leaders.
New resonance cross section calculational algorithms
Mathews, D.R.
1978-01-01
Improved resonance cross section calculational algorithms were developed and tested for inclusion in a fast reactor version of the MICROX code. The resonance energy portion of the MICROX code solves the neutron slowing-down equations for a two-region lattice cell on a very detailed energy grid (about 14,500 energies). In the MICROX algorithms, the exact P 0 elastic scattering kernels are replaced by synthetic (approximate) elastic scattering kernels which permit the use of an efficient and numerically stable recursion relation solution of the slowing-down equation. In the work described here, the MICROX algorithms were modified as follows: an additional delta function term was included in the P 0 synthetic scattering kernel. The additional delta function term allows one more moments of the exact elastic scattering kernel to be preserved without much extra computational effort. With the improved synthetic scattering kernel, the flux returns more closely to the exact flux below a resonance than with the original MICROX kernel. The slowing-down calculation was extended to a true B 1 hyperfine energy grid calculatn in each region by using P 1 synthetic scattering kernels and tranport-corrected P 0 collision probabilities to couple the two regions. 1 figure, 6 tables
Smith, D.L.
1987-11-01
Ratio measurements are routinely employed in studies of neutron interaction processes in order to generate new differential cross-section data or to test existing differential cross-section information through examination of the corresponding response in integral neutron spectra. Interpretation of such data requires that careful attention be given to details of the neutron spectra involved in these measurements. Two specific tasks are undertaken in the present investigation: (1) Using perturbation theory, a formula is derived which permits one to relate the ratio measured in a realistic quasimonoenergetic spectrum to the desired pure monoenergetic ratio. This expression involves only the lowest-order moments of the neutron energy distribution and corresponding parameters which serve to characterize the energy dependence of the differential cross sections, quantities which can generally be estimated with reasonable precision from the uncorrected data or from auxiliary information. (2) Using covariance methods, a general formalism is developed for calculating the uncertainty of a measured integral cross-section ratio which involves an arbitrary neutron spectrum. This formalism is employed to further examine the conditions which influence the sensitivity of such measured ratios to details of the neutron spectra and to their uncertainties. Several numerical examples are presented in this report in order to illustrate these principles, and some general conclusion are drawn concerning the development and testing of neutron cross-section data by means of ratio experiments. 16 refs., 1 fig., 4 tabs.
Smith, D.L.
1987-11-01
Ratio measurements are routinely employed in studies of neutron interaction processes in order to generate new differential cross-section data or to test existing differential cross-section information through examination of the corresponding response in integral neutron spectra. Interpretation of such data requires that careful attention be given to details of the neutron spectra involved in these measurements. Two specific tasks are undertaken in the present investigation: (1) Using perturbation theory, a formula is derived which permits one to relate the ratio measured in a realistic quasimonoenergetic spectrum to the desired pure monoenergetic ratio. This expression involves only the lowest-order moments of the neutron energy distribution and corresponding parameters which serve to characterize the energy dependence of the differential cross sections, quantities which can generally be estimated with reasonable precision from the uncorrected data or from auxiliary information. (2) Using covariance methods, a general formalism is developed for calculating the uncertainty of a measured integral cross-section ratio which involves an arbitrary neutron spectrum. This formalism is employed to further examine the conditions which influence the sensitivity of such measured ratios to details of the neutron spectra and to their uncertainties. Several numerical examples are presented in this report in order to illustrate these principles, and some general conclusion are drawn concerning the development and testing of neutron cross-section data by means of ratio experiments. 16 refs., 1 fig., 4 tabs
Numerical estimates of multiple reaction corrections in neutron cross-section measurements
Magnusson, G.
1979-04-01
A method to evaluate the effect of secondary neutrons in 14-15 MeV neutron cross-section measurements is presented. The emission spectra of secondary neutrons are calculated by means of the preequilibrium and statistical models. An expression for the collision probability in a homogenous body has been utilized in the calculations. (author)
Neutron cross section libraries for analysis of fusion neutronics experiments
Kosako, Kazuaki; Oyama, Yukio; Maekawa, Hiroshi; Nakamura, Tomoo
1988-03-01
We have prepared two computer code systems producing neutron cross section libraries to analyse fusion neutronics experiments. First system produces the neutron cross section library in ANISN format, i.e., the multi-group constants in group independent format. This library can be obtained by using the multi-group constant processing code system MACS-N and the ANISN format cross section compiling code CROKAS. Second system is for the continuous energy cross section library for the MCNP code. This library can be obtained by the nuclear data processing system NJOY which generates pointwise energy cross sections and the cross section compiling code MACROS for the MCNP library. In this report, we describe the production procedures for both types of the cross section libraries, and show six libraries with different conditions in ANISN format and a library for the MCNP code. (author)
Preparation of next generation set of group cross sections. 3
Kaneko, Kunio
2002-03-01
This fiscal year, based on the examination result about the evaluation energy range of heavy element unresolved resonance cross sections, the upper energy limit of the energy range, where ultra-fine group cross sections are produced, was raised to 50 keV, and an improvement of the group cross section processing system was promoted. At the same time, reflecting the result of studies carried out till now, a function producing delayed neutron data was added to the general-purpose group cross section processing system , thus the preparation of general purpose group cross section processing system has been completed. On the other hand, the energy structure, data constitution and data contents of next generation group cross section set were determined, and the specification of a 151 groups next generation group cross section set was defined. Based on the above specification, a concrete library format of the next generation cross section set has been determined. After having carried out the above-described work, using the general-purpose group cross section processing system , which was complete in this study, with use of the JENDL-3. 2 evaluated nuclear data, the 151 groups next generation group cross section of 92 nuclides and the ultra fine group resonance cross section library for 29 nuclides have been prepared. Utilizing the 151 groups next generation group cross section set and the ultra-fine group resonance cross-section library, a bench mark test calculation of fast reactors has been performed by using an advanced lattice calculation code. It was confirmed, by comparing the calculation result with a calculation result of continuous energy Monte Carlo code, that the 151 groups next generation cross section set has sufficient accuracy. (author)
Comparison of integral cross section values of several cross section libraries in the SAND-II format
Zijp, W.L.; Nolthenius, H.J.
1976-09-01
A comparison of some integral cross-section values for several cross-section libraries in the SAND-II format is presented. The integral cross-section values are calculated with the aid of the spectrum functions for a Watt fission spectrum, a 1/E spectrum and a Maxwellian spectrum. The libraries which are considered here are CCC-112B, ENDF/B-IV, DETAN74, LAPENAS and CESNEF. These 5 cross-section libraries used have all the SAND-II format. Discrepancies between cross-sections in the different libraries are indicated but not discussed
Implementation of the rapid cross section adjustment approach at General Electric
Cowan, C.L.; Kujawski, E.; Protsik, R.
1978-01-01
The General Electric rapid cross section adjustment approach was developed to use the shielding factor method for formulating multigroup cross sections. In this approach, space- and composition-dependent cross sections for a particular reactor or shield design are prepared from a generalized cross section library by the use of resonance self-shielding factors, and by the adjustment of elastic scattering cross sections for the local neutron flux spectra. The principal tool in the cross section adjustment package is the data processing code TDOWN. This code was specified to give the user a high degree of flexibility in the analysis of advanced reactor designs. Of particular interest in the analysis of critical experiments is the ability to carry out cell heterogeneity self-shielding calculations using a multiregion equivalence relationship, and the homogenization of the cross sections over the specified cell with the flux weighting obtained from transport theory calculations. Extensive testing of the rapid cross section adjustment approach, including comparisons with Monte Carlo methods, indicated that this approach can be utilized with a high degree of confidence in the design analysis of complex fast reactor systems. 2 figures, 1 table
Spectral history correction of microscopic cross sections for the PBR using the slowing down balance
Hudson, N.; Rahnema, F.; Ougouag, A. M.; Gougar, H. D.
2006-01-01
A method has been formulated to account for depletion effects on microscopic cross sections within a Pebble Bed Reactor (PBR) spectral zone without resorting to calls to the spectrum (cross section generation) code or relying upon table interpolation between data at different values of burnup. In this method, infinite medium microscopic cross sections, fine group fission spectra, and modulation factors are pre-computed at selected isotopic states. This fine group information is used with the local spectral zone nuclide densities to generate new cross sections for each spectral zone. The local spectrum used to generate these microscopic cross sections is estimated through the solution to the cell-homogenized, infinite medium slowing down balance equation during the flux calculation. This technique is known as Spectral History Correction (SHC), and it is formulated to specifically account for burnup within a spectral zone. It was found that the SHC technique accurately calculates local broad group microscopic cross sections with local burnup information. Good agreement is obtained with cross sections generated directly by the cross section generator. Encouraging results include improvement in the converged fuel cycle eigenvalue, the power peaking factor, and the flux. It was also found that the method compared favorably to the benchmark problem in terms of the computational speed. (authors)
MC^{2}-3: Multigroup Cross Section Generation Code for Fast Reactor Analysis
Lee, C. H. [Argonne National Lab. (ANL), Argonne, IL (United States); Yang, W. S. [Argonne National Lab. (ANL), Argonne, IL (United States)
2013-11-08
The MC^{2}-3 code is a Multigroup Cross section generation Code for fast reactor analysis, developed by improving the resonance self-shielding and spectrum calculation methods of MC^{2}-2 and integrating the one-dimensional cell calculation capabilities of SDX. The code solves the consistent P1 multigroup transport equation using basic neutron data from ENDF/B data files to determine the fundamental mode spectra for use in generating multigroup neutron cross sections. A homogeneous medium or a heterogeneous slab or cylindrical unit cell problem is solved in ultrafine (~2000) or hyperfine (~400,000) group levels. In the resolved resonance range, pointwise cross sections are reconstructed with Doppler broadening at specified isotopic temperatures. The pointwise cross sections are directly used in the hyperfine group calculation whereas for the ultrafine group calculation, self-shielded cross sections are prepared by numerical integration of the pointwise cross sections based upon the narrow resonance approximation. For both the hyperfine and ultrafine group calculations, unresolved resonances are self-shielded using the analytic resonance integral method. The ultrafine group calculation can also be performed for two-dimensional whole-core problems to generate region-dependent broad-group cross sections. Multigroup cross sections are written in the ISOTXS format for a user-specified group structure. The code is executable on UNIX, Linux, and PC Windows systems, and its library includes all isotopes of the ENDF/BVII. 0 data.
Measurement of the elastic cross section for positive pions on carbon at 142 MeV
Oyer, A.T.
1976-12-01
A measurement of the elastic cross section dsigma/dΩ was made for the reaction π + + 12 C → π + + 12 C with 142 MeV pions at ten angles ranging from 35 to 85 0 in the laboratory. This experiment was done at the Los Alamos Meson Physics Facility. A double focusing magnetic spectrometer observed a cylindrical styrofoam target. The resulting momentum spectra were recorded by an array of nineteen totally depleted surface barrier detectors located at the spectrometer's focal plane. The spectra from the styrofoam were composed of peaks representing proton elastic, carbon elastic, carbon inelastic, and carbon quasi-elastic channels. A function made of Gaussians representing the two body channels and a distribution representing the quasi-elastic channel was fit to the data using a nonlinear least squares algorithm. The ratio of the carbon elastic to proton elastic cross sections was calculated from the areas of the corresponding Gaussians and then multiplied by the proton elastic cross section of Bugg et al eliminating several sources of systematic errors such as beam normalization. The differential cross sections were found to have the usual diffraction structure with a forward peak and a minimum near 55 0 . Finally, the carbon elastic cross sections were compared to similar π - + 12 C cross sections of Binon et al using the optical model
Measurement of the elastic cross section for positive pions on carbon at 142 MeV
Oyer, A.T.
1976-12-01
A measurement of the elastic cross section dsigma/d..cap omega.. was made for the reaction ..pi../sup +/ + /sup 12/C ..-->.. ..pi../sup +/ + /sup 12/C with 142 MeV pions at ten angles ranging from 35 to 85/sup 0/ in the laboratory. This experiment was done at the Los Alamos Meson Physics Facility. A double focusing magnetic spectrometer observed a cylindrical styrofoam target. The resulting momentum spectra were recorded by an array of nineteen totally depleted surface barrier detectors located at the spectrometer's focal plane. The spectra from the styrofoam were composed of peaks representing proton elastic, carbon elastic, carbon inelastic, and carbon quasi-elastic channels. A function made of Gaussians representing the two body channels and a distribution representing the quasi-elastic channel was fit to the data using a nonlinear least squares algorithm. The ratio of the carbon elastic to proton elastic cross sections was calculated from the areas of the corresponding Gaussians and then multiplied by the proton elastic cross section of Bugg et al eliminating several sources of systematic errors such as beam normalization. The differential cross sections were found to have the usual diffraction structure with a forward peak and a minimum near 55/sup 0/. Finally, the carbon elastic cross sections were compared to similar ..pi../sup -/ + /sup 12/C cross sections of Binon et al using the optical model.
Integral-capture measurements and cross-section adjustments for Nd, Sm, and Eu
Anderl, R.A.; Schmittroth, F.; Harker, Y.D.
1981-07-01
Integral-capture reaction rates are reported for 143 Nd, 144 Nd, 145 Nd, 147 Sm, 151 Eu, 152 Eu, 153 Eu, and 154 Eu irradiated in different neutron spectra in EBR-II. These reaction rates are based primarily on mass-spectrometric measurements of the isotopic atom ratios of the capture product to the target nuclide. The neutron spectra are characterized using passive neutron dosimetry and spectrum-unfolding with the FERRET least-squares data analysis code. Reaction rates for the neutron spectrum monitors were determined by the radiometric technique using Ge(Li) spectrometers. These rates are also reported here. The integral data for the rare-earth samples and for the spectrum monitors were used in multigroup flux/cross-section adtustment analyses with FERRET to generate adjustments to 47 group representations of the ENDF/B-IV capture cross sections for the rare-earth isotopes. These adjusted cross sections are in good agreement with recent differential data and with adjusted cross sections based on STEK integral data. Examples are given of the use of the adjusted cross sections and covariance matrices for cross-section evaluation
Measurement of the elastic cross section for positive pions on carbon at 142 MeV
Oyer, A.T.
1976-01-01
A measurement of the elastic cross section dsigma/dOMEGA was made for the reaction π + + 12 C yields π + + 12 C with 142 MeV pions at ten angles ranging from 35 to 85 0 in the laboratory. This experiment was done at the Los Alamos Meson Physics Facility. A double focusing magnetic spectrometer observed a cylindrical styrofoam target. The resulting momentum spectra were recorded by an array of nineteen totally depleted surface barrier detectors located at the spectrometers focal plane. The spectra from the styrofoam were composed of peaks representing proton elastic, carbon elastic, carbon inelastic and carbon quasi-elastic channels. A function made of Gaussians representing the two body channels and a distribution representing the quasi-elastic channel was fit to the data using a nonlinear least squares algorithm. The ratio of the carbon elastic to proton elastic cross sections was calculated from the areas of the corresponding Gaussians and then multiplied by the proton elastic cross section of Bugg et al., eliminating several sources of systematic errors such as beam normalization. The differential cross sections were found to have the usual diffraction structure with a forward peak and a minimum near 55 0 . Finally, the carbon elastic cross sections were compared to similar π - + 12 C cross sections of Binon et al., using the optical model
VUV photoionization cross sections of HO2, H2O2, and H2CO.
Dodson, Leah G; Shen, Linhan; Savee, John D; Eddingsaas, Nathan C; Welz, Oliver; Taatjes, Craig A; Osborn, David L; Sander, Stanley P; Okumura, Mitchio
2015-02-26
The absolute vacuum ultraviolet (VUV) photoionization spectra of the hydroperoxyl radical (HO2), hydrogen peroxide (H2O2), and formaldehyde (H2CO) have been measured from their first ionization thresholds to 12.008 eV. HO2, H2O2, and H2CO were generated from the oxidation of methanol initiated by pulsed-laser-photolysis of Cl2 in a low-pressure slow flow reactor. Reactants, intermediates, and products were detected by time-resolved multiplexed synchrotron photoionization mass spectrometry. Absolute concentrations were obtained from the time-dependent photoion signals by modeling the kinetics of the methanol oxidation chemistry. Photoionization cross sections were determined at several photon energies relative to the cross section of methanol, which was in turn determined relative to that of propene. These measurements were used to place relative photoionization spectra of HO2, H2O2, and H2CO on an absolute scale, resulting in absolute photoionization spectra.
Stewart, L.
1979-03-01
In response to an action by the Standards Subcommittee of the Cross Section Evaluation Working Group, a workshop was convened to determine the status of available information on prompt fission neutron spectra. The experimental data were reviewed and theoretical models were developed. The current ENDF/B fission neutron spectra files were summarized. Further work is currently under way, especially to provide a better theoretical tool to represent energy-dependent fission spectra. 5 references
PEGASUS: a preequilibrium and multi-step evaporation code for neutron cross section calculation
Nakagawa, Tsuneo; Sugi, Teruo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Iijima, Shungo; Nishigori, Takeo
1999-06-01
The computer code PEGASUS was developed to calculate neutron-induced reaction cross sections on the basis of the closed form exciton model preequilibrium theory and the multi-step evaporation theory. The cross sections and emitted particle spectra are calculated for the compound elastic scattering, (n,{gamma}), (n,n`), (n,p), (n,{alpha}), (n,d), (n,t), (n,{sup 3}He), (n,2n), (n,n`p), (n,n`{alpha}), (n,n`d), (n,n`t), (n,2p) and (n,3n) reactions. The double differential cross sections of emitted particles are also calculated. The calculated results are written on a magnetic disk in the ENDF format. Parameter files and/or systematics formulas are provided for level densities, mass excess, radiation widths and inverse cross sections so that the input data to the code are made minimum. (author)
Polynomial parameterized representation of macroscopic cross section for PWR reactor
Fiel, Joao Claudio B.
2015-01-01
The purpose of this work is to describe, by means of Tchebychev polynomial, a parameterized representation of the homogenized macroscopic cross section for PWR fuel element as a function of soluble boron concentration, moderator temperature, fuel temperature, moderator density and 235 U 92 enrichment. Analyzed cross sections are: fission, scattering, total, transport, absorption and capture. This parameterization enables a quick and easy determination of the problem-dependent cross-sections to be used in few groups calculations. The methodology presented here will enable to provide cross-sections values to perform PWR core calculations without the need to generate them based on computer code calculations using standard steps. The results obtained by parameterized cross-sections functions, when compared with the cross-section generated by SCALE code calculations, or when compared with K inf , generated by MCNPX code calculations, show a difference of less than 0.7 percent. (author)
Average cross sections for the 252Cf neutron spectrum
Dezso, Z.; Csikai, J.
1977-01-01
A number of average cross sections have been measured for 252 Cf neutrons in (n, γ), (n,p), (n,2n), (n,α) reactions by the activation method and for fission by fission chamber. Cross sections have been determined for 19 elements and 45 reactions. The (n,γ) cross section values lie in the interval from 0.3 to 200 mb. The data as a function of target neutron number increases up to about N=60 with minimum near to dosed shells. The values lie between 0.3 mb and 113 mb. These cross sections decrease significantly with increasing the threshold energy. The values are below 20 mb. The data do not exceed 10 mb. Average (n,p) cross sections as a function of the threshold energy and average fission cross sections as a function of Zsup(4/3)/A are shown. The results obtained are summarized in tables
Criticality benchmark comparisons leading to cross-section upgrades
Alesso, H.P.; Annese, C.E.; Heinrichs, D.P.; Lloyd, W.R.; Lent, E.M.
1993-01-01
For several years criticality benchmark calculations with COG. COG is a point-wise Monte Carlo code developed at Lawrence Livermore National Laboratory (LLNL). It solves the Boltzmann equation for the transport of neutrons and photons. The principle consideration in developing COG was that the resulting calculation would be as accurate as the point-wise cross-sectional data, since no physics computational approximations were used. The objective of this paper is to report on COG results for criticality benchmark experiments in concert with MCNP comparisons which are resulting in corrections an upgrades to the point-wise ENDL cross-section data libraries. Benchmarking discrepancies reported here indicated difficulties in the Evaluated Nuclear Data Livermore (ENDL) cross-sections for U-238 at thermal neutron energy levels. This led to a re-evaluation and selection of the appropriate cross-section values from several cross-section sets available (ENDL, ENDF/B-V). Further cross-section upgrades anticipated
Calculation of atom displacement cross section for structure material
Liu Ping; Xu Yiping
2015-01-01
The neutron radiation damage in material is an important consideration of the reactor design. The radiation damage of materials mainly comes from atom displacements of crystal structure materials. The reaction cross sections of charged particles, cross sections of displacements per atom (DPA) and KERMA are the basis of radiation damage calculation. In order to study the differences of DPA cross sections with different codes and different evaluated nuclear data libraries, the DPA cross sections for structure materials were calculated with UNF and NJOY codes, and the comparisons of results were given. The DPA cross sections from different evaluated nuclear data libraries were compared. And the comparison of DPA cross sections between NJOY and Monte Carlo codes was also done. The results show that the differences among these evaluated nuclear data libraries exist. (authors)
Damage energy and displacement cross sections: survey and sensitivity. [Neutrons
Doran, D.G.; Parkin, D.M.; Robinson, M.T.
1976-10-01
Calculations of damage energy and displacement cross sections using the recommendations of a 1972 IAEA Specialists' Meeting are reviewed. The sensitivity of the results to assumptions about electronic energy losses in cascade development and to different choices respecting the nuclear cross sections is indicated. For many metals, relative uncertainties and sensitivities in these areas are sufficiently small that adoption of standard displacement cross sections for neutron irradiations can be recommended.
Total cross sections for heavy flavour production at HERA
Frixione, Stefano; Nason, P; Ridolfi, G; Frixione, S; Mangano, M L; Nason, P; Ridolfi, G
1995-01-01
We compute total cross sections for charm and bottom photoproduction at HERA energies, and discuss the relevant theoretical uncertainties. In particular we discuss the problems arising from the small-x region, the uncertainties in the gluon parton density, and the uncertainties in the hadronic component of the cross section. Total electroproduction cross sections, calculated in the Weizs\\"acker-Williams approximation, are also given.
Compact fitting formulas for electron-impact cross sections
Kim, Y.K.
1992-01-01
Compact fitting formulas, which contain four fitting constants, are presented for electron-impact excitation and ionization cross sections of atoms and ions. These formulas can fit experimental and theoretical cross sections remarkably well, when resonant structures are smoothed out, from threshold to high incident electron energies (<10 keV), beyond which relativistic formulas are more appropriate. Examples of fitted cross sections for some atoms and ions are presented. The basic form of the formula is valid for both atoms and molecules
Microscopic cross-section measurements by thermal neutron activation
Avila L, J.
1987-08-01
Microscopic cross sections measured by thermal neutron activation using RP-0 reactor at the Peruvian Nuclear Energy Institute. The method consists in measuring microscopic cross section ratios through activated samples, requiring being corrected in thermal and epithermal energetic range by Westcott formalism. Furthermore, the comptage ratios measured for each photopeak to its decay fraction should be normalized from interrelation between both processes above, activation microscopic cross sections are obtained
Precise measurements of neutron capture cross sections for FP
Nakamura, Shoji; Harada, Hideo; Katoh, Toshio
2000-01-01
The thermal neutron capture cross sections (σ 0 ) and the resonance integrals (I 0 ) of some fission products (FP), such as 137 Cs, 90 Sr, 99 Tc, 129 I and 135 Cs, were measured by the activation and γ-ray spectroscopic methods. Moreover, the cross section measurements were done for other FP elements, such as 127 I, 133 Cs and 134 Cs. This paper provides the summary of the FP cross section measurements, which have been performed by authors. (author)
Distorted eikonal cross sections: A time-dependent view
Turner, R.E.
1982-01-01
For Hamiltonians with two potentials, differential cross sections are written as time-correlation functions of reference and distorted transition operators. Distorted eikonal differential cross sections are defined in terms of straight-line and reference classical trajectories. Both elastic and inelastic results are obtained. Expressions for the inelastic cross sections are presented in terms of time-ordered cosine and sine memory functions through the use of the Zwanzig-Feshbach projection-operator method
Damage energy and displacement cross sections: survey and sensitivity
Doran, D.G.; Parkin, D.M.; Robinson, M.T.
1976-10-01
Calculations of damage energy and displacement cross sections using the recommendations of a 1972 IAEA Specialists' Meeting are reviewed. The sensitivity of the results to assumptions about electronic energy losses in cascade development and to different choices respecting the nuclear cross sections is indicated. For many metals, relative uncertainties and sensitivities in these areas are sufficiently small that adoption of standard displacement cross sections for neutron irradiations can be recommended
A method for measuring light ion reaction cross sections
Carlson, R.F.; Ingemarsson, A.; Lantz, M.
2005-03-01
An experimental procedure for measuring reaction cross sections of light ions in the energy range 20-50 MeV/nucleon, using a modified attenuation technique, is described. The detection method incorporates a forward detector that simultaneously measures the reaction cross sections for five different sizes of the solid angles in steps from 99.1 to 99.8% of the total solid angle. The final reaction cross section values are obtained by extrapolation to the full solid angle
Systematics of fission cross sections at the intermediate energy region
Fukahori, Tokio; Chiba, Satoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
1997-03-01
The systematics was obtained with fitting experimental data for proton induced fission cross sections of Ag, {sup 181}Ta, {sup 197}Au, {sup 206,207,208}Pb, {sup 209}Bi, {sup 232}Th, {sup 233,235,238}U, {sup 237}Np and {sup 239}Pu above 20 MeV. The low energy cross section of actinoid nuclei is omitted from systematics study, since the cross section has a complicated shape and strongly depends on characteristic of nucleus. The fission cross sections calculated by the systematics are in good agreement with experimental data. (author)
Fragmentation cross sections outside the limiting-fragmentation regime
Sümmerer, K
2003-01-01
The empirical parametrization of fragmentation cross sections, EPAX, has been successfully applied to estimate fragment production cross sections in reactions of heavy ions at high incident energies. It is checked whether a similar parametrization can be found for proton-induced spallation around 1 GeV, the range of interest for ISOL-type RIB facilities. The validity of EPAX for medium-energy heavy-ion induced reactions is also checked. Only a few datasets are available, but in general EPAX predicts the cross sections rather well, except for fragments close to the projectile, where the experimental cross sections are found to be larger.
Neutron-capture cross sections from indirect measurements
Scielzo N.D.
2012-02-01
Full Text Available Cross sections for compound-nuclear reactions reactions play an important role in models of astrophysical environments and simulations of the nuclear fuel cycle. Providing reliable cross section data remains a formidable task, and direct measurements have to be complemented by theoretical predictions and indirect methods. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f reactions, but need to be improved upon for applications to capture reactions.
Positive Scattering Cross Sections using Constrained Least Squares
Dahl, J.A.; Ganapol, B.D.; Morel, J.E.
1999-01-01
A method which creates a positive Legendre expansion from truncated Legendre cross section libraries is presented. The cross section moments of order two and greater are modified by a constrained least squares algorithm, subject to the constraints that the zeroth and first moments remain constant, and that the standard discrete ordinate scattering matrix is positive. A method using the maximum entropy representation of the cross section which reduces the error of these modified moments is also presented. These methods are implemented in PARTISN, and numerical results from a transport calculation using highly anisotropic scattering cross sections with the exponential discontinuous spatial scheme is presented
Neutron-capture Cross Sections from Indirect Measurements
Escher, J E; Burke, J T; Dietrich, F S; Ressler, J J; Scielzo, N D; Thompson, I J
2011-10-18
Cross sections for compound-nuclear reactions play an important role in models of astrophysical environments and simulations of the nuclear fuel cycle. Providing reliable cross section data remains a formidable task, and direct measurements have to be complemented by theoretical predictions and indirect methods. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f) reactions, but need to be improved upon for applications to capture reactions.
Adjustement of multigroup cross sections using fast reactor integral data
Renke, C.A.C.
1982-01-01
A methodology for the adjustment of multigroup cross section is presented, structured with aiming to compatibility the limitated number of measured values of integral parameters known and disponible, and the great number of cross sections to be adjusted the group of cross section used is that obtained from the Carnaval II calculation system, understanding as formular the sets of calculation methods and data bases. The adjustment is realized, using the INCOAJ computer code, developed in function of one statistical formulation, structural from the bayer considerations, taking in account the measurement processes of cross section and integral parameters defined on statistical bases. (E.G.) [pt
Neutron cross section measurements for the Fast Breeder Program
Block, R.C.
1979-06-01
This research was concerned with the measurement of neutron cross sections of importance to the Fast Breeder Reactor. The capture and total cross sections of fission products ( 101 102 104 Ru, 143 145 Nd, 149 Sm, 95 97 Mo, Cs, Pr, Pd, 107 Pd, 99 Tc) and tag gases (Kr, 78 80 Kr) were measured up to 100 keV. Filtered neutron beams were used to measure the capture cross section of 238 U (with an Fe filter) and the total cross section of Na (with a Na filter). A radioactive neutron capture detector was developed. A list of publications is included
Criticality studies of fast assemblies with the new 27-group cross-section set
Garg, S.B.; Shukla, V.K.
1976-01-01
A test of 27-group cross-section set (Garg-set) recently derived from ENDF/B library has been carried out in the criticality studies of the Pu 239 , U 235 and U 233 based metal, oxide and carbide fuelled fast critical assemblies. A total of twenty fast critical assemblies of different sizes and varying neutron spectra have been selected for analysis. Based on these analyses it has been observed that the Garg-set predicts well the criticality of uranium and plutonium based hard-spectra assemblies. In the soft-spectra systems it underpredicts criticality because of the following reasons: (a) It makes use of the higher capture cross-sections of structural and coolant elements given in ENDF/B - Version IV library. (b) It does not account for the resonance self-shielding effects of cross-sections. It has also been observed that the Garg-set gives better results than the MABBN-set for dense and dilute plutonium-based and the hard uranium-based assemblies. This superior trend of the Garg-set is slightly lost in the uranium-based dilute systems because of large differences in the capture cross-sections of structural elements of these two sets. (author)
Cross Sections for Inner-Shell Ionization by Electron Impact
Llovet, Xavier, E-mail: xavier@ccit.ub.edu [Centres Científics i Tecnològics, Universitat de Barcelona, Lluís Solé i Sabarís 1-3, 08028 Barcelona (Spain); Powell, Cedric J. [Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8370 (United States); Salvat, Francesc [Facultat de Física (ECM and ICC), Universitat de Barcelona, Diagonal 645, 08028 Barcelona (Spain); Jablonski, Aleksander [Institute of Physical Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, 01-224 Warsaw (Poland)
2014-03-15
An analysis is presented of measured and calculated cross sections for inner-shell ionization by electron impact. We describe the essentials of classical and semiclassical models and of quantum approximations for computing ionization cross sections. The emphasis is on the recent formulation of the distorted-wave Born approximation by Bote and Salvat [Phys. Rev. A 77, 042701 (2008)] that has been used to generate an extensive database of cross sections for the ionization of the K shell and the L and M subshells of all elements from hydrogen to einsteinium (Z = 1 to Z = 99) by electrons and positrons with kinetic energies up to 1 GeV. We describe a systematic method for evaluating cross sections for emission of x rays and Auger electrons based on atomic transition probabilities from the Evaluated Atomic Data Library of Perkins et al. [Lawrence Livermore National Laboratory, UCRL-ID-50400, 1991]. We made an extensive comparison of measured K-shell, L-subshell, and M-subshell ionization cross sections and of Lα x-ray production cross sections with the corresponding calculated cross sections. We identified elements for which there were at least three (for K shells) or two (for L and M subshells) mutually consistent sets of cross-section measurements and for which the cross sections varied with energy as expected by theory. The overall average root-mean-square deviation between the measured and calculated cross sections was 10.9% and the overall average deviation was −2.5%. This degree of agreement between measured and calculated ionization and x-ray production cross sections was considered to be very satisfactory given the difficulties of these measurements.
Evaluation of plasma-wave spectral density from cross-power spectra
Ilic, D.B.; Harker, K.J.
1975-01-01
The plasma-wave spectral density is evaluated by performing a spatial Fourier transform on experimental cross-power spectra of ion acoustic waves. The cross-power spectra are recorded on analog magnetic tape, converted to digital form, transferred to digital magnetic tape, and Fourier transformed on a digital computer. The important effects of sampling, finite data strings, and data smoothing on the end results are discussed and illustrated. The results indicate the usefulness of the spectral density method for the study of nonlinear wave phenomena. (auth)
Investigation of the 93Nb neutron cross-sections in resonance energy range
Grigoriev, Yu.V.; Kitaev, V.Ya.; Zhuravlev, B.V.; Sinitsa, V.V.; Borzakov, S.B.; Faikov-Stanchik, H.; Ilchev, G.; Mezentseva, Zh.V.; Panteleev, Ts.Ts.; Kim, G.N.
2002-01-01
The results of gamma-ray multiplicity spectra and transmission measurements for 93 Nb in energy range 21.5 eV-100 keV are presented. Gamma spectra from 1 to 7 multiplicity were measured on the 501 m and 121 m flight paths of the IBR-30 using a 16-section scintillation detector with a NaI(Tl) crystals of a total volume of 36 l and a 16-section liquid scintillation detector of a total volume of 80 l for metallic samples of 50, 80 mm in diameter and 1, 1.5 mm thickness with 100% 93 Nb. Besides, the total and scattering cross-section of 93 Nb were measured by means batteries of B-10 and He-3 counters on the 124 m, 504 m and 1006 m flight paths of the IBR-30. Spectra of multiplicity distribution were obtained for resolved resonances in the energy region E=30-6000 eV and for energy groups in the energy region E=21.5 eV- 100 keV. They were used for determination of the average multiplicity, resonance parameters and capture cross-section in energy groups and for low-laying resonances of 93 Nb. Standard capture cross-sections of 238 U and experimental gamma-ray multiplicity spectra were also used for determination of capture cross section 93 Nb in energy groups. Similar values were calculated using the ENDF/B-6 and JENDL-3 evaluated data libraries with the help of the GRUKON computer program. Within the limits of experimental errors there is observed an agreement between the experiment and calculation, but in some groups the experimental values differ from the calculated ones. (author)
Erradi, L.; Karouani, K.
1994-01-01
Many multigroup neutron cross section libraries have been processed from basic evaluated nuclear data for use in neutron dosimetry, reactor shielding calculation and in the development of fusion reactors. Most of these libraries have been tested only for fission spectra and were not validated for fusion spectra. Fifteen of these libraries such as DOSCROS84, IRDF85 and ENDFB5 have been used along with the neutron spectra unfolding code SAND II to evaluate about fifteen threshold detector saturated activities. The comparison between these computed activities and the measured ones of a set of foils placed in different places along the axis of a paraffin cylinder and irradiated by 14 MeV neutrons generated by a D-T source, hence giving rise to complex spectra, leads to different types of discrepancies. The analysis of these discrepancies allows to select from these libraries the ones that can be recommended. 1 fig., 4 refs. (author)
First Double Excitation Cross Sections of Helium Measured for 100-keV Proton Impact
Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A. [Laboratoire Collisions, Agregats, Reactivite, IRSAMC, UMR 5589, CNRS and Universite Paul Sabatier, 31062 Toulouse Cedex (France); Godunov, A.L.; Schipakov, V.A. [Troitsk Institute for Innovation and Fusion Research, Troitsk, Moscow region, 142092 (Russia)
1997-12-01
Excitation cross sections of the (2s{sup 2}){sup 1}S, (2p{sup 2}){sup 1}D , and (2s2p){sup 1}P autoionizing states of helium, produced in collisions with 100-keV protons, have been measured for the first time. Using a high resolution electron spectroscopy together with a recently proposed parametrization of autoionizing resonances distorted by Coulomb interaction in the final state makes it possible to extract from electron spectra {ital total cross sections} as well as {ital magnetic sublevel populations.} These new experimental data are briefly compared with out theoretical calculations. {copyright} {ital 1997} {ital The American Physical Society}
First Double Excitation Cross Sections of Helium Measured for 100-keV Proton Impact
Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A.; Godunov, A.L.; Schipakov, V.A.
1997-01-01
Excitation cross sections of the (2s 2 ) 1 S, (2p 2 ) 1 D , and (2s2p) 1 P autoionizing states of helium, produced in collisions with 100-keV protons, have been measured for the first time. Using a high resolution electron spectroscopy together with a recently proposed parametrization of autoionizing resonances distorted by Coulomb interaction in the final state makes it possible to extract from electron spectra total cross sections as well as magnetic sublevel populations. These new experimental data are briefly compared with out theoretical calculations. copyright 1997 The American Physical Society
Time-dependent density functional theory description of total photoabsorption cross sections
Tenorio, Bruno Nunes Cabral; Nascimento, Marco Antonio Chaer; Rocha, Alexandre Braga
2018-02-01
The time-dependent version of the density functional theory (TDDFT) has been used to calculate the total photoabsorption cross section of a number of molecules, namely, benzene, pyridine, furan, pyrrole, thiophene, phenol, naphthalene, and anthracene. The discrete electronic pseudo-spectra, obtained in a L2 basis set calculation were used in an analytic continuation procedure to obtain the photoabsorption cross sections. The ammonia molecule was chosen as a model system to compare the results obtained with TDDFT to those obtained with the linear response coupled cluster approach in order to make a link with our previous work and establish benchmarks.
Evaluated neutron-induced cross sections for 40Ca from 20 to 40 MeV
Hetrick, D.M.; Fu, C.Y.; Larson, D.C.
1982-09-01
Nuclear model codes were used to compute cross sections for neutron-induced reactions on 40 Ca for incident energies from 20 to 40 MeV. The input parameters for the model codes were determined through analysis of experimental data in this energy region. Computed cross sections along with emission spectra for each product were combined into an Evaluated Nuclear Data File (ENDF) using the proposed format for charged-particle reactions. Discussion of the models used, the resulting calculations, and the final evaluated data file are presented
Corporate Social Responsibility: A Cross Sectional Examination of Incentivization.
1995-09-01
which address organizational behavior: Corporate Social Responsibility ( CSR ), Expense Preference Approach (EPA), Resource Dependency Theory (RDT...i V *>V CORPORATE SOCIAL RESPONSIBILITY : A CROSS SECTIONAL EXAMINATION OF INCENTIVIZATION THESIS Jennifer A. Block, B.S. First Lieutenant, USAF...Distribution/ Availability Codes Dist m Avail and/or Special \\&\\W 0\\1 CORPORATE SOCIAL RESPONSIBILITY : A CROSS SECTIONAL EXAMINATION OF
238U subthreshold neutron induced fission cross section
Difilippo, F.C.; Perez, R.B.; De Saussure, G.; Olsen, D.K.; Ingle, R.W.
1976-01-01
High resolution measurements of the 238 U neutron induced fission cross section are reported for neutron energies between 600 eV and 2 MeV. The average subthreshold fission cross section between 10 and 100 keV was found to be 44 +- 6 μb
Learning of Cross-Sectional Anatomy Using Clay Models
Oh, Chang-Seok; Kim, Ji-Young; Choe, Yeon Hyeon
2009-01-01
We incorporated clay modeling into gross anatomy and neuro-anatomy courses to help students understand cross-sectional anatomy. By making clay models, cutting them and comparing cut surfaces to CT and MR images, students learned how cross-sectional two-dimensional images were created from three-dimensional structure of human organs. Most students…
Photoionization cross sections: present status and future needs
Manson, S.T.
1988-01-01
The existing experimental data situation for photoionization cross section of ground-state atoms, excited states and positive ions is reviewed. The ability of theory to predict these cross sections is also discussed. The likely progress for the near future is presented [pt
Parametric equations for calculation of macroscopic cross sections
Botelho, Mario Hugo; Carvalho, Fernando
2015-01-01
Neutronic calculations of the core of a nuclear reactor is one thing necessary and important for the design and management of a nuclear reactor in order to prevent accidents and control the reactor efficiently as possible. To perform these calculations a library of nuclear data, including cross sections is required. Currently, to obtain a cross section computer codes are used, which require a large amount of processing time and computer memory. This paper proposes the calculation of macroscopic cross section through the development of parametric equations. The paper illustrates the proposal for the case of macroscopic cross sections of absorption (Σa), which was chosen due to its greater complexity among other cross sections. Parametric equations created enable, quick and dynamic way, the determination of absorption cross sections, enabling the use of them in calculations of reactors. The results show efficient when compared with the absorption cross sections obtained by the ALPHA 8.8.1 code. The differences between the cross sections are less than 2% for group 2 and less than 0.60% for group 1. (author)
Tearing mode stability of tokamak plasmas with elliptical cross section
Carreras, B.A.; Holmes, J.A.; Hicks, H.R.; Lynch, V.E.
1981-02-01
The effect of the ellipticity of the plasma cross section on tearing mode stability is investigated. The induced coupling between modes is shown to be destabilizing; however, the modification of the equilibrium tends to stabilize the tearing modes. The net effect depends on the manner in which the equilibrium is modified as the plasma cross-section shape is changed
Simplified polynomial representation of cross sections for reactor calculation
Dias, A.M.; Sakai, M.
1985-01-01
It is shown a simplified representation of a cross section library generated by transport theory using the cell model of Wigner-Seitz for typical PWR fuel elements. The effect of burnup evolution through tables of reference cross sections and the effect of the variation of the reactor operation parameters considered by adjusted polynomials are presented. (M.C.K.) [pt
Graphs of neutron cross section data for fusion reactor development
Asami, Tetsuo; Tanaka, Shigeya
1979-03-01
Graphs of neutron cross section data relevant to fusion reactor development are presented. Nuclides and reaction types in the present compilation are based on a WRENDA request list from Japan for fusion reactor development. The compilation contains various partial cross sections for 55 nuclides from 6 Li to 237 Np in the energy range up to 20 MeV. (author)
Evaluated activation cross-sections and intercomparison of the ...
mental data cross-section with the theoretical codes, to study the quality of the theoretical ... the cross-section, angular distribution, double differential data, gamma ..... TALYS. TENDL. Figure 6. Excitation function of the 87Sr(p, 2n)86Y reaction.
Differential bremsstrahlung and pair production cross sections at high energies
Olsen, Haakon A.
2003-01-01
Detailed differential cross sections for high energy bremsstrahlung and pair production are derived with specific attention to the differences between the two processes, which are considerable. For the integrated cross sections, which are the only cross sections specifically known until now, the final state integration theorem guarantees that the exact cross section formulas can be exchanged between bremsstrahlung and pair production by the same substitution rules as for the Born-approximation Bethe-Heitler cross sections, for any amount of atomic screening. In fact the theorem states that the Coulomb corrections to the integrated bremsstrahlung and pair production cross sections are identical for any amount of screening. The analysis of the basic differential cross sections leads to fundamental physical differences between bremsstrahlung and pair production. Coulomb corrections occur for pair production in the strong electric field of the atom for 'large' momentum transfer of the order of mc. For bremsstrahlung, on the other hand, the Coulomb corrections take place at a 'large' distance from the atom of the order of ((ℎ/2π)/mc)ε, with a 'small' momentum transfer mc/ε, where ε is the initial electron energy in units of mc 2 . And the Coulomb corrections can be large, of the order of larger than (Z/137) 2 , which is considerably larger than the integrated cross section corrections
Total Cross Sections at High Energies An update
Fazal-e-Aleem, M; Alam, Saeed; Qadee-Afzal, M
2002-01-01
Current and Future measurements for the total cross sections at E-811, PP2PP, CSM, FELIX and TOTEM have been analyzed using various models. In the light of this study an attempt has been made to focus on the behavior of total cross section at very high energies.
pp production cross sections and the constraint method
Anjos, J.C.; Santoro, A.F.S.; Souza, M.H.G.
1983-01-01
A method of constructing production cross sections that satisfy the constraints represented by the first few moments is shown to give an excellent account of the data when applied to the high energy pp production cross section ν sub(n) (s) plotted as functions of n. (Author) [pt
1997-01-01
The data base relevant to an evaluation of the 10 B(n,α) standard cross sections have been improved through interlaboratory collaboration. Changes in the evaluated 10 B(n,α) cross sections resulted form the measurements made since the ENDF/B-VI evaluation have been estimated. 12 refs, 4 figs
Systematics of new isotopic production cross sections from neon projectiles
Chen, C.X.; Guzik, T.G.; McMahon, M.; Wefel, J.P.; Flores, I.; Lindstrom, P.J.; Tull, C.E.; Mitchell, J.W.; Cronqvist, M.; Crawford, H.J.
1996-02-01
New isotopic production cross sections from 22 Ne projectiles at 377,581 and 891 MeV/nucleon in a liquid hydrogen target have been measured. These data allow to investigate the projectile energy and nuclear composition dependence of the cross sections. The comparisons between data and predictions can have important consequences in source abundance investigations. (K.A.)
Systematics of new isotopic production cross sections from neon projectiles
Chen, C X; Guzik, T G; McMahon, M; Wefel, J P [Louisiana State Univ., Baton Rouge, LA (United States); Flores, I; Lindstrom, P J; Tull, C E [Lawrence Berkeley Lab., CA (United States); Mitchell, J W [National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center; Cronqvist, M; Crawford, H J [California Univ., Berkeley, CA (United States). Space Sciences Lab.; and others
1996-02-01
New isotopic production cross sections from {sup 22}Ne projectiles at 377,581 and 891 MeV/nucleon in a liquid hydrogen target have been measured. These data allow to investigate the projectile energy and nuclear composition dependence of the cross sections. The comparisons between data and predictions can have important consequences in source abundance investigations. (K.A.). 9 refs.
Fusion cross sections from measurements of delayed X-rays
Pacheco, A.J.; Gregorio, D.E. di; Fernandez Niello, J.O; Elgue, M.
1988-01-01
The program XRAY is a FORTRAN 77 computer code for the extraction of fusion cross sections from delayed X-ray measurements. This is accomplished by calculating the theoretical expressions of the time dependence of the evaporation-residue cross sections and taking them as adjustable parameters in a χ 2 minimization procedure. (orig.)
The effect of the decay data on activation cross section
Huang Xiaolong
2002-01-01
The effect of the decay data on evaluation of activation cross section is investigated. Present work shows that these effects must be considered carefully when activation cross section is evaluated. Sometime they are main reason for causing the discrepancies among the experimental data
Tables of RCN-2 fission-product cross section evaluation
Gruppelaar, H.
1979-05-01
This report (continuation of ECN-13 and ECN-33) describes the third part of the RCN-2 evaluation of neutron cross sections for fission product nuclides in KEDAK format. It contains evaluated data for nine nuclides, i.e. 142 Nd, 143 Nd, 144 Nd, 145 Nd, 146 Nd, 147 Nd, 148 Nd, 150 Nd and 147 Pm. Most emphasis has been given to the evaluation of the radiative capture cross section, in order to provide a data base for adjustment calculations using results of integral measurements. Short evaluation reports are given for this cross section. The evaluated capture cross sections are compared with recent experimental differential and integral data. Graphs are given of the capture cross sections at neutron energies above 1 keV, in which also adjusted point cross sections, based upon integral STEK and CFRMF data have been plotted. Moreover, the results are compared with those of the well-known ENDF/B-IV evaluation for fission product nucleides. Finally, evaluation summaries are given, which include tables of other important neutron cross sections, such as the total, elastic scattering and inelastic scattering cross sections
Nuclear characteristics of Pu fueled LWR and cross section sensitivities
Takeda, Toshikazu [Osaka Univ., Suita (Japan). Faculty of Engineering
1998-03-01
The present status of Pu utilization to thermal reactors in Japan, nuclear characteristics and topics and cross section sensitivities for analysis of Pu fueled thermal reactors are described. As topics we will discuss the spatial self-shielding effect on the Doppler reactivity effect and the cross section sensitivities with the JENDL-3.1 and 3.2 libraries. (author)
Evaluation of covariance for 238U cross sections
Kawano, Toshihiko; Nakamura, Masahiro; Matsuda, Nobuyuki; Kanda, Yukinori
1995-01-01
Covariances of 238 U are generated using analytic functions for representation of the cross sections. The covariances of the (n,2n) and (n,3n) reactions are derived with a spline function, while the covariances of the total and the inelastic scattering cross section are estimated with a linearized nuclear model calculation. (author)
Q.C.D. estimates of hadronic cross sections
Navelet, H.; Peschanski, R.
1983-03-01
Estimates for hadron-hadron cross-sections are made using the leading log approximation of Q.C.D. The rise of the total inelastic pp cross-sections at high energy is reproduced, thanks to the competition between the small parton-parton interaction and the large multiplicity of gluons predicted by Q.C.D
Second order effects in adjustment processes of cross sections
Silva, F.C. da; D'Angelo, A.; Gandini, A.; Rado, V.
1982-01-01
An iterative processe, that take in account the non linear effects of some integral quantities in relation to cross sections, is used to execute an adjustment of cross sections of some elements that constitute the fast reactors shielding. (E.G.) [pt
Excitons in Core-Shell Nanowires with Polygonal Cross Sections.
Sitek, Anna; Urbaneja Torres, Miguel; Torfason, Kristinn; Gudmundsson, Vidar; Bertoni, Andrea; Manolescu, Andrei
2018-04-11
The distinctive prismatic geometry of semiconductor core-shell nanowires leads to complex localization patterns of carriers. Here, we describe the formation of optically active in-gap excitonic states induced by the interplay between localization of carriers in the corners and their mutual Coulomb interaction. To compute the energy spectra and configurations of excitons created in the conductive shell, we use a multielectron numerical approach based on the exact solution of the multiparticle Hamiltonian for electrons in the valence and conduction bands, which includes the Coulomb interaction in a nonperturbative manner. We expose the formation of well-separated quasidegenerate levels, and focus on the implications of the electron localization in the corners or on the sides of triangular, square, and hexagonal cross sections. We obtain excitonic in-gap states associated with symmetrically distributed electrons in the spin singlet configuration. They acquire large contributions due to Coulomb interaction, and thus are shifted to much higher energies than other states corresponding to the conduction electron and the vacancy localized in the same corner. We compare the results of the multielectron method with those of an electron-hole model, and we show that the latter does not reproduce the singlet excitonic states. We also obtain the exciton lifetime and explain selection rules which govern the recombination process.
Nuclear fission and neutron-induced fission cross-sections
James, G.D.; Lynn, J.E.; Michaudon, A.; Rowlands, J.; de Saussure, G.
1981-01-01
A general presentation of current knowledge of the fission process is given with emphasis on the low energy fission of actinide nuclei and neutron induced fission. The need for and the required accuracy of fission cross section data in nuclear energy programs are discussed. A summary is given of the steps involved in fission cross section measurement and the range of available techniques. Methods of fission detection are described with emphasis on energy dependent changed and detector efficiency. Examples of cross section measurements are given and data reduction is discussed. The calculation of fission cross sections is discussed and relevant nuclear theory including the formation and decay of compound nuclei and energy level density is introduced. A description of a practical computation of fission cross sections is given.
Fission cross section measurements of actinides at LANSCE
Tovesson, Fredrik [Los Alamos National Laboratory; Laptev, Alexander B [Los Alamos National Laboratory; Hill, Tony S [INL
2010-01-01
Fission cross sections of a range of actinides have been measured at the Los Alamos Neutron Science Center (LANSCE) in support of nuclear energy applications. By combining measurement at two LANSCE facilities, Lujan Center and the Weapons Neutron Research center (WNR), differential cross sections can be measured from sub-thermal energies up to 200 MeV. Incident neutron energies are determined using the time-of-flight method, and parallel-plate ionization chambers are used to measure fission cross sections relative to the {sup 235}U standard. Recent measurements include the {sup 233,238}U, {sup 239,242}Pu and {sup 243}Am neutron-induced fission cross sections. In this paper preliminary results for cross section data of {sup 243}Am and {sup 233}U will be presented.
Applications of the BEam Cross section Analysis Software (BECAS)
Blasques, José Pedro Albergaria Amaral; Bitsche, Robert; Fedorov, Vladimir
2013-01-01
A newly developed framework is presented for structural design and analysis of long slender beam-like structures, e.g., wind turbine blades. The framework is based on the BEam Cross section Analysis Software – BECAS – a finite element based cross section analysis tool. BECAS is used for the gener......A newly developed framework is presented for structural design and analysis of long slender beam-like structures, e.g., wind turbine blades. The framework is based on the BEam Cross section Analysis Software – BECAS – a finite element based cross section analysis tool. BECAS is used...... for the generation of beam finite element models which correctly account for effects stemming from material anisotropy and inhomogeneity in cross sections of arbitrary geometry. These type of modelling approach allows for an accurate yet computationally inexpensive representation of a general class of three...
ENDF/B-5 fission product cross section evaluations
Schenter, R.E.; England, T.R.
1979-12-01
Cross section evaluations were made for the 196 fission product nuclides on the ENDF/B-5 data files. Most of the evaluations involve updating the capture cross sections of the important absorbers for fast and thermal reactor systems. This included updating thermal values, resonance integrals, resonance parameter sets, and fast capture cross sections. For the fast capture results generalized least-squares calculations were made with the computer code FERRET. Input for these cross section adjustments included nuclear models calculations and both integral and differential experimental data results. The differential cross sections and their uncertainties were obtained from the CSIRS library. Integral measurement results came from CFRMF and STEK Assemblies 500, 1000, 2000, 3000, 4000. Comparisons of these evaluations with recent capture measurements are shown. 15 figures, 10 tables
Electron collision cross section sets of TMS and TEOS vapours
Kawaguchi, S.; Takahashi, K.; Satoh, K.; Itoh, H.
2017-05-01
Reliable and detailed sets of electron collision cross sections for tetramethylsilane [TMS, Si(CH3)4] and tetraethoxysilane [TEOS, Si(OC2H5)4] vapours are proposed. The cross section sets of TMS and TEOS vapours include 16 and 20 kinds of partial ionization cross sections, respectively. Electron transport coefficients, such as electron drift velocity, ionization coefficient, and longitudinal diffusion coefficient, in those vapours are calculated by Monte Carlo simulations using the proposed cross section sets, and the validity of the sets is confirmed by comparing the calculated values of those transport coefficients with measured data. Furthermore, the calculated values of the ionization coefficient in TEOS/O2 mixtures are compared with measured data to confirm the validity of the proposed cross section set.
Cross sections for hadron and lepton production processes
Bhattacharya, R.
1976-01-01
Charged heavy lepton production in proton-proton collisions is studied. Motivated by recent experimental results from the Stanford Linear Accelerator Center a parton model analysis is given of the reaction p + p → L + + L - + x → μ +- + e/ -+ / + neutrinos + x. Results are presented for the total cross section and the differential cross sections with respect to the invariant mass squared of the final charged leptons and the transverse momenta of each one of them. The two-photon mechanism for pair production in colliding beam exeriments is considered. Through the use of mapped invariant integration variables, a reliable exact numerical calculation of the cross section for the production of muon and pion pairs by the two-photon mechanism is provided. Results are given for the exact total cross sections and also the differential cross sections with respect to the invariant mass squared of the pair. These are compared to the results obtained from the equivalent photon approximation method
Classical scattering cross section in sputtering transport theory
Zhang Zhulin
2002-01-01
For Lindhard scaling interaction potential scattering commonly used in sputtering theory, the authors analyzed the great difference between Sigmund's single power and the double power cross sections calculated. The double power cross sections can give a much better approximation to the Born-Mayer scattering in the low energy region (m∼0.1). In particular, to solve the transport equations by K r -C potential interaction given by Urbassek few years ago, only the double power cross sections (m∼0.1) can yield better approximate results for the number of recoils. Therefore, the Sigmund's single power cross section might be replaced by the double power cross sections in low energy collision cascade theory
Target dependence of K+-nucleus total cross sections
Jiang, M.F.; Ernst, D.J.; Chen, C.M.
1995-01-01
We investigate the total cross section and its target dependence for K + -nucleus scattering using a relativistic momentum-space optical potential model which incorporates relativistically normalized wave functions, invariant two-body amplitudes, covariant kinematics, and an exact full-Fermi averaging integral. The definition of the total cross section in the presence of a Coulomb interaction is reviewed and the total cross section is calculated in a way that is consistent with what is extracted from experiment. In addition, the total cross sections for a nucleus and for the deuteron are calculated utilizing the same theory. This minimizes the dependence of the ratio of these cross sections on the details of the theory. The model dependence of the first-order optical potential calculations is investigated. The theoretical results are found to be systematically below all existing data
Temperature-dependent absorption cross sections for hydrogen peroxide vapor
Nicovich, J. M.; Wine, P. H.
1988-01-01
Relative absorption cross sections for hydrogen peroxide vapor were measured over the temperature ranges 285-381 K for lambda = 230 nm-295 nm and 300-381 K for lambda = 193 nm-350 nm. The well established 298 K cross sections at 202.6 and 228.8 nm were used as an absolute calibration. A significant temperature dependence was observed at the important tropospheric photolysis wavelengths lambda over 300 nm. Measured cross sections were extrapolated to lower temperatures, using a simple model which attributes the observed temperature dependence to enhanced absorption by molecules possessing one quantum of O-O stretch vibrational excitation. Upper tropospheric photodissociation rates calculated using the extrapolated cross sections are about 25 percent lower than those calculated using currently recommended 298 K cross sections.
Kirilova, D.; Belousov, S.; Ilieva, K.
2011-01-01
The objective of this work is a generation of new version of the BGL multigroup cross-section to extend the region of its applicability. The existing library version is problem oriented for VVER-1000 type of reactors and was generated by collapsing of the VITAMIN-B6 problem independent cross-section fine-group library applying the VVER-1000 reactor middle plane spectrum in cylindrical geometry. The new version BGLex additionally contains cross-sections averaged on the corresponding spectra of the surveillance specimen's (SS) region for VVER-1000 type of reactors. Comparative analysis of the neutron spectra for different one-dimensional geometry models that could be applied for the cross-section collapsing using the software package SCALE, showed a high sensitivity of the results to the geometry model. That is why a neutron importance assessment was done for the SS region using the adjoint solution calculated by the two-dimensional code DORT and problem-independent library VITAMIN-B6. The one-dimensional geometry model applied to the cross-section collapsing were determined by the material limits above the reactor core in axial direction z as for every material a homogenization in radial direction was done. The material homogenization in radial direction was done by material weighing taking into account the adjoint solution as well as the neutron source. The one-dimensional geometry model comprising the homogenized weighed materials was applied for the cross-section generation of the fine-group library VITAMIN-B6 to the broad-group structure of BGL library. The new version BGLex was extended with cross-sections for the SS region. Verification and validation of the new version BGLex is forthcoming. It includes comparison between the calculated results with the new version BGLex and the libraries BGL and VITAMIN-B6 and comparison with experimental results. (author)
Kirilova, D.; Belousov, S.; Ilieva, K.
2011-01-01
The objective of this work is a generation of new version of the BGL multigroup cross-section to extend the region of its applicability. The existing library version is problem oriented for VVER-1000 type of reactors and was generated by collapsing of the VITAMIN-B6 problem independent cross-section fine-group library applying the VVER-1000 reactor middle plane spectrum in cylindrical geometry. The new version BGLex additionally contains cross-sections averaged on the corresponding spectra of the surveillance specimen's (SS) region for VVER-1000 type of reactors. Comparative analysis of the neutron spectra for different one-dimensional geometry models that could be applied for the cross-section collapsing using the software package SCALE, showed a high sensitivity of the results to the geometry model. That is why a neutron importance assessment was done for the SS region using the adjoint solution calculated by the two-dimensional code DORT and problem-independent library VITAMIN-B6. The one-dimensional geometry model applied to the cross-section collapsing were determined by the material limits above the reactor core in axial direction z as for every material a homogenization in radial direction was done. The material homogenization in radial direction was done by material weighing taking into account the adjoint solution as well as the neutron source. The one-dimensional geometry model comprising the homogenized weighed materials was applied for the cross-section generation of the fine-group library VITAMIN-B6 to the broad-group structure of BGL library. The new version BGLex was extended with cross-sections for the SS region. Verification and validation of the new version BGLex is forthcoming. It includes comparison between the calculated results with the new version BGLex and the libraries BGL and VITAMIN-B6 and comparison with experimental results. (author)
Meeting cross-section requirements for nuclear-energy design
Weisbin, C.R.; de Saussure, G.; Santoro, R.T. (Oak Ridge National Lab., TN (USA)); Gilai, T. (Ben-Gurion Univ. of the Negev, Beersheba (Israel))
1982-01-01
Current requirements in cross-section data that are essential to nuclear-energy programmes are summarized and explained and some insight into how these data might be obtained is provided. The six sections of the paper describe: design parameters and target accuracies; data collection, evaluation and analysis; determination of high-accuracy differential nuclear data for technological applications; status of selected evaluated nuclear data; analysis of benchmark testing; identification of important cross sections and inferred needs.
Cross-sectional nanophotoluminescence studies of Stark effects in self-assembled quantum dots
Htoon, H.; Keto, J. W.; Baklenov, O.; Holmes, A. L. Jr.; Shih, C. K.
2000-01-01
By using a cross-sectional geometry, we show the capability to perform single-dot spectroscopy in self-assembled quantum dots using far-field optics. By using this method, we study the quantum-confined Stark effect in self-assembled quantum dots. For single-stack quantum dots (QDs), we find that the spectra are redshifted with an increase in electric field. For vertically coupled double-stack quantum dots, while most of the QDs are redshifted, some QDs show blueshifted spectra, which can be interpreted as an evidence of coupled QD molecules. (c) 2000 American Institute of Physics
Collision, scattering and absorption differential cross-sections in double-photon Compton scattering
Dewan, R.; Saddi, M.B.; Sandhu, B.S.; Singh, B.; Ghumman, B.S.
2005-01-01
The collision, scattering and absorption differential cross-sections of double-photon Compton scattering are measured experimentally for 0.662 MeV incident gamma photons. Two simultaneously emitted gamma quanta are investigated using a slow-fast coincidence technique having 25 ns resolving time. The coincidence spectra for different energy windows of one of the two final photons are recorded using HPGe detector. The experimental data do not suffer from inherent energy resolution of gamma detector and provide more faithful reproduction of the distribution under the full energy peak of recorded coincidence spectra. The present results are in agreement with the currently acceptable theory of this higher order process
MPI version of NJOY and its application to multigroup cross-section generation
Alpan, A.; Haghighat, A.
1999-07-01
Multigroup cross-section libraries are needed in performing neutronics calculations. These libraries are referred to as broad-group libraries. The number of energy groups and group structure are highly dependent on the application and/or user's objectives. For example, for shielding calculations, broad-group libraries such as SAILOR and BUGLE with 47-neutron and 20-gamma energy groups are used. The common procedure to obtain a broad-group library is a three-step process: (1) processing pointwise ENDF (PENDF) format cross sections; (2) generating fine-group cross sections; and (3) collapsing fine-group cross sections to broad-group. The NJOY code is used to prepare fine-group cross sections by processing pointwise ENDF data. The code has several modules, each one performing a specific task. For instance, the module RECONR performs linearization and reconstruction of the cross sections, and the module GROUPR generates multigroup self-shielded cross sections. After fine-group, i.e., groupwise ENDF (GENDF), cross sections are produced, cross sections are self-shielded, and a one-dimensional transport calculation is performed to obtain flux spectra at specific regions in the model. These fluxes are then used as weighting functions to collapse the fine-group cross sections to obtain a broad-group cross-section library. The third step described is commonly performed by the AMPX code system. SMILER converts NJOY GENDF filed to AMPX master libraries, AJAX collects the master libraries. BONAMI performs self-shielding calculations, NITAWL converts the AMPX master library to a working library, XSDRNPM performs one-dimensional transport calculations, and MALOCS collapses fine-group cross sections to broad-group. Finally, ALPO is used to generate ANISN format libraries. In this three-step procedure, generally NJOY requires the largest amount of CPU time. This time varies depending on the user's specified parameters for each module, such as reconstruction tolerances
MPI version of NJOY and its application to multigroup cross-section generation
Alpan, A.; Haghighat, A.
1999-01-01
Multigroup cross-section libraries are needed in performing neutronics calculations. These libraries are referred to as broad-group libraries. The number of energy groups and group structure are highly dependent on the application and/or user's objectives. For example, for shielding calculations, broad-group libraries such as SAILOR and BUGLE with 47-neutron and 20-gamma energy groups are used. The common procedure to obtain a broad-group library is a three-step process: (1) processing pointwise ENDF (PENDF) format cross sections; (2) generating fine-group cross sections; and (3) collapsing fine-group cross sections to broad-group. The NJOY code is used to prepare fine-group cross sections by processing pointwise ENDF data. The code has several modules, each one performing a specific task. For instance, the module RECONR performs linearization and reconstruction of the cross sections, and the module GROUPR generates multigroup self-shielded cross sections. After fine-group, i.e., groupwise ENDF (GENDF), cross sections are produced, cross sections are self-shielded, and a one-dimensional transport calculation is performed to obtain flux spectra at specific regions in the model. These fluxes are then used as weighting functions to collapse the fine-group cross sections to obtain a broad-group cross-section library. The third step described is commonly performed by the AMPX code system. SMILER converts NJOY GENDF filed to AMPX master libraries, AJAX collects the master libraries. BONAMI performs self-shielding calculations, NITAWL converts the AMPX master library to a working library, XSDRNPM performs one-dimensional transport calculations, and MALOCS collapses fine-group cross sections to broad-group. Finally, ALPO is used to generate ANISN format libraries. In this three-step procedure, generally NJOY requires the largest amount of CPU time. This time varies depending on the user's specified parameters for each module, such as reconstruction tolerances, temperatures
Infrared absorption cross sections for ethane (C2H6) in the 3 μm region
Harrison, Jeremy J.; Allen, Nicholas D.C.; Bernath, Peter F.
2010-01-01
Infrared absorption cross sections for ethane have been measured in the 3 μm spectral region from spectra recorded using a high-resolution FTIR spectrometer (Bruker IFS 125/HR). Results are presented for pure ethane gas from spectra recorded at 0.004 cm -1 resolution and for mixtures with dry synthetic air from spectra obtained at 0.015 cm -1 resolution (calculated as 0.9/MOPD using the Bruker definition of resolution), at a number of temperatures and pressures appropriate for atmospheric conditions. Intensities were calibrated using three ethane spectra (recorded at 278, 293, and 323 K) taken from the Pacific Northwest National Laboratory (PNNL) IR database.
AFCI-2.0 Neutron Cross Section Covariance Library
Herman, M.; Herman, M; Oblozinsky, P.; Mattoon, C.M.; Pigni, M.; Hoblit, S.; Mughabghab, S.F.; Sonzogni, A.; Talou, P.; Chadwick, M.B.; Hale, G.M.; Kahler, A.C.; Kawano, T.; Little, R.C.; Yount, P.G.
2011-03-01
materials and fission products, and 20 actinides. Covariances are given in 33-energy groups, from 10?5 eV to 19.6 MeV, obtained by processing with LANL processing code NJOY using 1/E flux. In addition to these 110 files, the library contains 20 files with nu-bar covariances, 3 files with covariances of prompt fission neutron spectra (238,239,240-Pu), and 2 files with mu-bar covariances (23-Na, 56-Fe). Over the period of three years several working versions of the library have been released and tested by ANL and INL reactor analysts. Useful feedback has been collected allowing gradual improvements of the library. In addition, QA system was developed to check basic properties and features of the whole library, allowing visual inspection of uncertainty and correlations plots, inspection of uncertainties of integral quantities with independent databases, and dispersion of cross sections between major evaluated libraries. The COMMARA-2.0 beta version of the library was released to ANL and INL reactor analysts in October 2010. The final version, described in the present report, was released in March 2011.
AFCI-2.0 Neutron Cross Section Covariance Library
Herman, M.; Oblozinsky, P.; Mattoon, C.M.; Pigni, M.; Hoblit, S.; Mughabghab, S.F.; Sonzogni, A.; Talou, P.; Chadwick, M.B.; Hale, G.M.; Kahler, A.C.; Kawano, T.; Little, R.C.; Yount, P.G.
2011-01-01
structural materials and fission products, and 20 actinides. Covariances are given in 33-energy groups, from 10?5 eV to 19.6 MeV, obtained by processing with LANL processing code NJOY using 1/E flux. In addition to these 110 files, the library contains 20 files with nu-bar covariances, 3 files with covariances of prompt fission neutron spectra (238,239,240-Pu), and 2 files with mu-bar covariances (23-Na, 56-Fe). Over the period of three years several working versions of the library have been released and tested by ANL and INL reactor analysts. Useful feedback has been collected allowing gradual improvements of the library. In addition, QA system was developed to check basic properties and features of the whole library, allowing visual inspection of uncertainty and correlations plots, inspection of uncertainties of integral quantities with independent databases, and dispersion of cross sections between major evaluated libraries. The COMMARA-2.0 beta version of the library was released to ANL and INL reactor analysts in October 2010. The final version, described in the present report, was released in March 2011.
Varlamov, V.V. [Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation); Davydov, A.I. [Lomonosov Moscow State University, Physics Faculty, Moscow (Russian Federation); Ishkhanov, B.S. [Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation); Lomonosov Moscow State University, Physics Faculty, Moscow (Russian Federation)
2017-09-15
Data on partial photoneutron reaction cross sections (γ, 1n), (γ, 2n), and (γ, 3n) for {sup 59}Co obtained in two experiments carried out at Livermore (USA) were analyzed. The sources of radiation in both experiments were the monoenergetic photon beams from the annihilation in flight of relativistic positrons. The total yield was sorted by the neutron multiplicity, taking into account the difference in the neutron energy spectra for different multiplicity. The two quoted studies differ in the method of determining the neutron. Significant systematic disagreements between the results of the two experiments exist. They are considered to be caused by large systematic uncertainties in partial cross sections, since they do not satisfy physical criteria for reliability of the data. To obtain reliable cross sections of partial and total photoneutron reactions a new method combining experimental data and theoretical evaluation was used. It is based on the experimental neutron yield cross section which is rather independent of neutron multiplicity and the transitional neutron multiplicity functions of the combined photonucleon reaction model (CPNRM). The model transitional multiplicity functions were used for the decomposition of the neutron yield cross section into the contributions of partial reactions. The results of the new evaluation noticeably differ from the partial cross sections obtained in the two experimental studies are under discussion. (orig.)
Cross section data for ionization of important cyanides
Kaur, Jaspreet; Antony, Bobby
2015-01-01
Highlights: • Multi centre spherical complex optical potential formalism used to find the CS. • Effective method (CSP-ic) to derive ionization contribution from inelastic CS. • Result shows excellent accord with previous results and consistent behaviour. • Maiden attempt to find CS for many cyanide molecules. • Strong correlation observed between peak of ionization with target properties. - Abstract: This article presents cross section calculations for interactions of important cyanides with electrons possessing energies beginning from ionization threshold of the target molecule to 5 keV. These data are pursued to meet the ever increasing demand for cross sections by the relevant atomic and molecular community for modelling astrophysical, atmospheric and technological domains. The calculations have been executed using an amalgam of multi centre spherical complex optical potential (MSCOP) formalism and complex scattering potential-ionization contribution (CSP-ic) method. Cross sections are compared with experimental and theoretical data wherever available. Strong correlations are observed for the cross sections which affirms consistent and reliable cross sections. Isomeric effect has been interpreted using variation of cross section with structure and target properties. Our cross sections will be tabulated in atomic collision database for use in modelling various statistical and dynamical quantities.
Evaluation of kerma in carbon and the carbon cross sections
Axton, E.J.
1992-02-01
A preliminary simultaneous least squares fit to measurements of kerma in carbon, and carbon cross sections taken from the ENDF/B-V file was carried out. In the calculation the shapes of the total cross section and the various partial cross sections were rigid but their absolute values were allowed to float in the fit within the constraints of the ENDF/B-V uncertainties. The construction of the ENDF/B-V file imposed improbable shapes, particularly in the case of the (12)C(n,n'3(alpha)) reaction, which were incompatible with direct measurements of kerma and of the reaction cross sections. Consequently a new evaluation of the cross section data became necessary. Since the available time was limited the new evaluation concentrated particularly on those aspects of the ENDF/B-V carbon file which would have most impact on kerma calculations. Following the new evaluation of cross sections new tables of kerma factors were produced. Finally, the simultaneous least squares fit to measurements of kerma and the new cross section file was repeated
Neutron standard cross sections in reactor physics - Need and status
Carlson, A.D.
1990-01-01
The design and improvement of nuclear reactors require detailed neutronics calculations. These calculations depend on comprehensive libraries of evaluated nuclear cross sections. Most of the cross sections that form the data base for these evaluations have been measured relative to neutron cross-section standards. The use of these standards can often simplify the measurement process by eliminating the need for a direct measurement of the neutron fluence. The standards are not known perfectly, however; thus the accuracy of a cross-section measurement is limited by the uncertainty in the standard cross section relative to which it is measured. Improvements in a standard cause all cross sections measured relative to that standard to be improved. This is the reason for the emphasis on improving the neutron cross-section standards. The continual process of measurement and evaluation has led to improvements in the accuracy and range of applicability of the standards. Though these improvements have been substantial, this process must continue in order to obtain the high-quality standards needed by the user community
Density-dependent expressions for photoionization cross-sections
Sun Weiguo; Ma Xiaoguang; Cheng Yansong
2004-06-07
Alternative expressions for photoionization cross-sections and dielectric influence functions are suggested to study the photoionization cross-sections of atoms in solid system. The basic picture is that the photoionization cross-section of atoms in a real system can be described as the coupling between quantum quantity (QQ) and classical quantity (CQ) parts. The QQ part represents the photoionization cross-sections of an isolated particle, while the CQ part may represent most of the important influence of the macroscopic effects (e.g., the interactions of all surrounding polarized particles, and the dielectric property, etc.) on the photoionization cross-sections. The applications to the barium system show that the number-density-dependent new photoionization formula not only obtains the same cross-sections as those from the first order approximation for ideal gas, but also can generate the cross-sections for solid barium by transforming those of ideal gas of the same species using the dielectric influence function.
Parameterized representation of macroscopic cross section for PWR reactor
Fiel, João Cláudio Batista; Carvalho da Silva, Fernando; Senra Martinez, Aquilino; Leal, Luiz C.
2015-01-01
Highlights: • This work describes a parameterized representation of the homogenized macroscopic cross section for PWR reactor. • Parameterization enables a quick determination of problem-dependent cross-sections to be used in few group calculations. • This work allows generating group cross-section data to perform PWR core calculations without computer code calculations. - Abstract: The purpose of this work is to describe, by means of Chebyshev polynomials, a parameterized representation of the homogenized macroscopic cross section for PWR fuel element as a function of soluble boron concentration, moderator temperature, fuel temperature, moderator density and 235 92 U enrichment. The cross-section data analyzed are fission, scattering, total, transport, absorption and capture. The parameterization enables a quick and easy determination of problem-dependent cross-sections to be used in few group calculations. The methodology presented in this paper will allow generation of group cross-section data from stored polynomials to perform PWR core calculations without the need to generate them based on computer code calculations using standard steps. The results obtained by the proposed methodology when compared with results from the SCALE code calculations show very good agreement
Density-dependent expressions for photoionization cross-sections
Sun Weiguo; Ma Xiaoguang; Cheng Yansong
2004-01-01
Alternative expressions for photoionization cross-sections and dielectric influence functions are suggested to study the photoionization cross-sections of atoms in solid system. The basic picture is that the photoionization cross-section of atoms in a real system can be described as the coupling between quantum quantity (QQ) and classical quantity (CQ) parts. The QQ part represents the photoionization cross-sections of an isolated particle, while the CQ part may represent most of the important influence of the macroscopic effects (e.g., the interactions of all surrounding polarized particles, and the dielectric property, etc.) on the photoionization cross-sections. The applications to the barium system show that the number-density-dependent new photoionization formula not only obtains the same cross-sections as those from the first order approximation for ideal gas, but also can generate the cross-sections for solid barium by transforming those of ideal gas of the same species using the dielectric influence function
Cross section data for ionization of important cyanides
Kaur, Jaspreet; Antony, Bobby, E-mail: bka.ism@gmail.com
2015-11-15
Highlights: • Multi centre spherical complex optical potential formalism used to find the CS. • Effective method (CSP-ic) to derive ionization contribution from inelastic CS. • Result shows excellent accord with previous results and consistent behaviour. • Maiden attempt to find CS for many cyanide molecules. • Strong correlation observed between peak of ionization with target properties. - Abstract: This article presents cross section calculations for interactions of important cyanides with electrons possessing energies beginning from ionization threshold of the target molecule to 5 keV. These data are pursued to meet the ever increasing demand for cross sections by the relevant atomic and molecular community for modelling astrophysical, atmospheric and technological domains. The calculations have been executed using an amalgam of multi centre spherical complex optical potential (MSCOP) formalism and complex scattering potential-ionization contribution (CSP-ic) method. Cross sections are compared with experimental and theoretical data wherever available. Strong correlations are observed for the cross sections which affirms consistent and reliable cross sections. Isomeric effect has been interpreted using variation of cross section with structure and target properties. Our cross sections will be tabulated in atomic collision database for use in modelling various statistical and dynamical quantities.
Positron induced scattering cross sections for hydrocarbons relevant to plasma
Singh, Suvam; Antony, Bobby
2018-05-01
This article explores positron scattering cross sections by simple hydrocarbons such as ethane, ethene, ethyne, propane, and propyne. Chemical erosion processes occurring on the surface due to plasma-wall interactions are an abundant source of hydrocarbon molecules which contaminate the hydrogenic plasma. These hydrocarbons play an important role in the edge plasma region of Tokamak and ITER. In addition to this, they are also one of the major components in the planetary atmospheres and astrophysical mediums. The present work focuses on calculation of different positron impact interactions with simple hydrocarbons in terms of the total cross section (Qtot), elastic cross section (Qel), direct ionization cross section (Qion), positronium formation cross section (Qps), and total ionization cross section (Qtion). Knowing that the positron-plasma study is one of the trending fields, the calculated data have diverse plasma and astrophysical modeling applications. A comprehensive study of Qtot has been provided where the inelastic cross sections have been reported for the first time. Comparisons are made with those available from the literature, and a good agreement is obtained with the measurements.
The total collision cross section in the glory region
Biesen, J.J.H. van den.
1982-01-01
Chapter 1 presents a calculation of approximate total cross sections in the glory region from noble gas potentials. The relations between the main features of the total cross section and the properties of the potential to which these are sensitive are extensively investigated in chapter II. A beam apparatus has been developed, which allows for accurate measurements on the total cross section. All effects due to the finite angular and velocity resolution of the apparatus can be eliminated from the data to yield actual total cross sections as a function of the relative velocity. This facilitates a comparison to total cross sections predicted by potentials available in the literature. A brief description of the apparatus and of the data reduction is given in chapter III. The total cross section data obtained for various noble gas combinations are presented and analysed in chapter IV, where also a large number of potentials proposed in the literature is tested. In chapter V the quenching of the glories in the case of a non-spherical interaction is analysed. Subsequently, total cross section data for some atom-molecule systems are discussed. (Auth.)
Poster - 18: New features in EGSnrc for photon cross sections
Ali, Elsayed; Mainegra-Hing, Ernesto; Rogers, David W.O. [The Ottawa Hospital Cancer Centre, National Research Council Canada, Carleton University (Canada)
2016-08-15
Purpose: To implement two new features in the EGSnrc Monte Carlo system. The first is an option to account for photonuclear attenuation, which can contribute a few percent to the total cross section at the higher end of the energy range of interest to medical physics. The second is an option to use exact NIST XCOM photon cross sections. Methods: For the first feature, the photonuclear total cross sections are generated from the IAEA evaluated data. In the current, first-order implementation, after a photonuclear event, there is no energy deposition or secondary particle generation. The implementation is validated against deterministic calculations and experimental measurements of transmission signals. For the second feature, before this work, if the user explicitly requested XCOM photon cross sections, EGSnrc still used its own internal incoherent scattering cross sections. These differ by up to 2% from XCOM data between 30 keV and 40 MeV. After this work, exact XCOM incoherent scattering cross sections are an available option. Minor interpolation artifacts in pair and triplet XCOM cross sections are also addressed. The default for photon cross section in EGSnrc is XCOM except for the new incoherent scattering cross sections, which have to be explicitly requested. The photonuclear, incoherent, pair and triplet data from this work are available for elements and compounds for photon energies from 1 keV to 100 GeV. Results: Both features are implemented and validated in EGSnrc.Conclusions: The two features are part of the standard EGSnrc distribution as of version 4.2.3.2.
First Measurements of High Frequency Cross-Spectra from a Pair of Large Michelson Interferometers
Chou, Aaron S.; Gustafson, Richard; Hogan, Craig; Kamai, Brittany; Kwon, Ohkyung; Lanza, Robert; McCuller, Lee; Meyer, Stephan S.; Richardson, Jonathan; Stoughton, Chris; Tomlin, Raymond; Waldman, Samuel; Weiss, Rainer
2016-09-01
Measurements are reported of high frequency cross-spectra of signals from the Fermilab Holometer, a pair of co-located 39 m, high power Michelson interferometers. The instrument obtains differential position sensitivity to cross-correlated signals far exceeding any previous measurement in a broad frequency band extending to the 3.8 MHz inverse light crossing time of the apparatus. A model of universal exotic spatial shear correlations that matches the Planck scale holographic information bound of space-time position states is excluded to 4.6{\\sigma} significance.
From cutting-edge pointwise cross-section to groupwise reaction rate: A primer
Sublet Jean-Christophe; Fleming Michael; Gilbert Mark R.
2017-01-01
The nuclear research and development community has a history of using both integral and differential experiments to support accurate lattice-reactor, nuclear reactor criticality and shielding simulations, as well as verification and validation efforts of cross sections and emitted particle spectra. An important aspect to this type of analysis is the proper consideration of the contribution of the neutron spectrum in its entirety, with correct propagation of uncertainties and standard deviatio...
A coupled-cluster study of photodetachment cross sections of closed-shell anions
Cukras, Janusz; Decleva, Piero; Coriani, Sonia
2014-11-01
We investigate the performance of Stieltjes Imaging applied to Lanczos pseudo-spectra generated at the coupled cluster singles and doubles, coupled cluster singles and approximate iterative doubles and coupled cluster singles levels of theory in modeling the photodetachment cross sections of the closed shell anions H-, Li-, Na-, F-, Cl-, and OH-. The accurate description of double excitations is found to play a much more important role than in the case of photoionization of neutral species.
A coupled-cluster study of photodetachment cross sections of closed-shell anions
Cukras, Janusz; Decleva, Piero; Coriani, Sonia
2014-01-01
We investigate the performance of Stieltjes Imaging applied to Lanczos pseudo-spectra generated at the coupled cluster singles and doubles, coupled cluster singles and approximate iterative doubles and coupled cluster singles levels of theory in modeling the photodetachment cross sections of the closed shell anions H − , Li − , Na − , F − , Cl − , and OH − . The accurate description of double excitations is found to play a much more important role than in the case of photoionization of neutral species
Auclair, J M; Hubert, P; Joly, R; Vendryes, G; Jacrot, B; Netter, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Galula, M [Centre National de la Recherche Scientifique (CNRS), 91 - Gif-sur-Yvette (France)
1955-07-01
It presents the experimental measurements of cross section of fissile nuclei for slow neutrons to improve the understanding of some heavy nuclei of great importance in the study of nuclear reactors. The different experiments are divided in three categories. In the first part, it studied the variation with energy of the cross sections of natural uranium, {sup 233}U, {sup 235}U and {sup 239}Pu. Two measurement techniques are used: the time-of-flight spectrometer and the crystal spectrometer. In a second part, the fission cross sections of {sup 233}U and {sup 239}Pu for thermal neutrons are compared using a neutron flux from EL-2 going through a double fission chamber. The matter quantity contained in each source is measured by counting the {alpha} activity with a solid angle counter. Finally, the average cross section of {sup 236}U for a spectra of neutrons from the reactor is measured by studying the {beta} activity of {sup 237}U formed by the reaction {sup 236}U (n, {gamma}) {sup 237}U in a sample of {sup 236}U irradiated in the Saclay reactor (EL-2). (M.P.)
Neutron total scattering cross sections of elemental antimony
Smith, A.B.; Guenther, P.T.; Whalen, J.F.
1982-11-01
Neutron total cross sections are measured from 0.8 to 4.5 MeV with broad resolutions. Differential-neutron-elastic-scattering cross sections are measured from 1.5 to 4.0 MeV at intervals of 50 to 200 keV and at scattering angles distributed between 20 and 160 degrees. Lumped-level neutron-inelastic-scattering cross sections are measured over the same angular and energy range. The exPerimental results are discussed in terms of an optical-statistical model and are compared with respective values given in ENDF/B-V.
Measurements of fission cross-sections. Chapter 4
James, G.D.
1981-01-01
The steps involved in the measurement of fission cross sections are summarized and the range of techniques available are considered. Methods of fission detection are described with particular emphasis on the neutron energy dependent properties of the fission process and the details of fragment energy loss which can lead to energy-dependent changes in detector efficiency. Selected examples of fission cross-section measurements are presented and methods of data reduction, storage, analysis and evaluation, are examined. Finally requested accuracies for fission cross section data are compared to estimated available accuracies. (U.K.)
Total cross section for relativistic positronium interaction with atom
Pak, A.S.; Tarasov, A.V.
1985-01-01
Total cross sections of interaction of positronium relativistic atoms with atoms are calculated. Calculations are conducted within the framework of potential theory in Born approximaton. Contributions in total cross section of coherent (σsub(coh)) and incoherent (σsub(inc)) parts are analyzed. It is shown that for light elements σsub(inc) value is comparable with σsub(coh), and for heavy ones the ratio σsub(inc)/σsub(coh) sufficiently exceeds Zsup(-1) (Z-charge of the atomic nucleus. Numerical calculation results are presented. A conclusion is made on importance of the coherent part account during the calculation of total cross sections
Actinide neutron-induced fission cross section measurements at LANSCE
Tovesson, Fredrik K [Los Alamos National Laboratory; Laptev, Alexander B [Los Alamos National Laboratory; Hill, Tony S [INL
2010-01-01
Fission cross sections of a range of actinides have been measured at the Los Alamos Neutron Science Center (LANSCE) in support of nuclear energy applications in a wide energy range from sub-thermal energies up to 200 MeV. A parallel-plate ionization chamber are used to measure fission cross sections ratios relative to the {sup 235}U standard while incident neutron energies are determined using the time-of-flight method. Recent measurements include the {sup 233,238}U, {sup 239-242}Pu and {sup 243}Am neutron-induced fission cross sections. Obtained data are presented in comparison with ex isting evaluations and previous data.
Fission cross sections in the intermediate energy region
Lisowski, P.W.; Gavron, A.; Parker, W.E.; Ullmann, J.L.; Balestrini, S.J.; Carlson, A.D.; Wasson, O.A.; Hill, N.W.
1991-01-01
Until recently there has been very little cross section data for neutron-induced fission in the intermediate energy region, primarily because no suitable neutron source has existed. At Los Alamos, the WNR target-4 facility provides a high-intensity source of neutrons nearly ideal for fission measurements extending from a fraction of a MeV to several hundred MeV. This paper summarizes the status of fission cross section data in the intermediate energy range (En > 30 MeV) and presents our fission cross section data for 235 U and 238 U compared to intranuclear cascade and statistical model predictions
Fission cross sections in the intermediate energy region
Lisowski, P.W.; Gavron, A.; Parker, W.E.; Ullmann, J.L.; Balestrini, S.J. (Los Alamos National Lab., NM (USA)); Carlson, A.D.; Wasson, O.A. (National Inst. of Standards and Technology, Gaithersburg, MD (USA)); Hill, N.W. (Oak Ridge National Lab., TN (USA))
1991-01-01
Until recently there has been very little cross section data for neutron-induced fission in the intermediate energy region, primarily because no suitable neutron source has existed. At Los Alamos, the WNR target-4 facility provides a high-intensity source of neutrons nearly ideal for fission measurements extending from a fraction of a MeV to several hundred MeV. This paper summarizes the status of fission cross section data in the intermediate energy range (En > 30 MeV) and presents our fission cross section data for {sup 235}U and {sup 238}U compared to intranuclear cascade and statistical model predictions.
Drell-Yan cross section in the jet calculus scheme
Tanaka, Hidekazu; Kobayashi, Hirokazu
2009-01-01
We calculate factorized cross sections for lepton pair production mediated by a virtual photon in hadron-hadron collisions using the jet calculus scheme, in which a kinematical constraint due to parton radiation is taken into account. This method guarantees a proper phase space boundary for subtraction terms. Some properties of the calculated cross sections are examined. We also discuss matching between the hard scattering cross sections and parton showers at the next-to-leading logarithmic (NLL) order of quantum chromodynamics (QCD). (author)
Habit, Production, and the Cross-Section of Stock Returns
Chen, Andrew Y.
2014-01-01
Solutions to the equity premium puzzle should inform us about the cross-section of stock returns. An external habit model with heterogeneous firms reproduces numerous stylized facts about both the equity premium and the value premium. The equity premium is large, time-varying, and linked with consumption volatility. The cross-section of expected returns is log-linear in B/M, and the slope matches the data. The explanation for the value premium lies in the interaction between the cross-section...
Use of nuclear reaction models in cross section calculations
Grimes, S.M.
1975-03-01
The design of fusion reactors will require information about a large number of neutron cross sections in the MeV region. Because of the obvious experimental difficulties, it is probable that not all of the cross sections of interest will be measured. Current direct and pre-equilibrium models can be used to calculate non-statistical contributions to neutron cross sections from information available from charged particle reaction studies; these are added to the calculated statistical contribution. Estimates of the reliability of such calculations can be derived from comparisons with the available data. (3 tables, 12 figures) (U.S.)
Comparison of fission and capture cross sections of minor actinides
Nakagawa, Tsuneo; Iwamoto, Osamu
2003-01-01
The fission and capture cross sections of minor actinides given in JENDL-3.3 are compared with other evaluated data and experimental data. The comparison was made for 32 nuclides of Th-227, 228, 229, 230, 233, 234, Pa-231, 232, 233, U-232, 234, 236, 237, Np-236, 237, 238, Pu-236, 237, 238, 242, 244, Am-241, 242, 242m, 243, Cm-242, 243, 244, 245, 246, 247 and 248. Given in the present report are figures of these cross sections and tables of cross sections at 0.0253 eV and resonance integrals. (author)
LHCb cross-section measurements with heavy flavour jets
Michielin, Emanuele
2017-01-01
Cross-section measurements of jets originating from the hadronization of beauty ($b$) and charm ($c$) quarks at LHCb give the unique opportunity to probe Parton Distribution Functions (PDFs) at low and large momentum fraction and to test the Standard Model in the forward region. In this poster the production of $t\\bar{t}$ pairs in the forward region, the measurement of the $W+b\\bar{b}$ and $W+c\\bar{c}$ cross-section and the measurement of the $Z\\rightarrow b\\bar{b}$ cross-section are presented.
Cross sections and transport properties for Na+ in (DXE gas
Nikitović Željka D.
2016-01-01
Full Text Available In this work we select most probable reactions of alkali metal ion Na+ with dimethoxyethane (DXE molecule. Appropriate gas phase enthalpies of formation for the products were used to calculate scattering cross section as a function of kinetic energy with Denpoh-Nanbu theory. Calculated cross sections were compared with existing experimental results obtained by guided ion beam tandem mass spectrometry. Three body association reactions of ions with DXE is studied and compared to experimental results. Calculated cross sections were used to obtain transport parameters for alkali metal ion in DXE gas. [Projekat Ministarstva nauke Republike Srbije, br. ON 171037 i br. III 410011
Neutron total scattering cross sections of elemental antimony
Smith, A.B.; Guenther, P.T.; Whalen, J.F.
1982-11-01
Neutron total cross sections are measured from 0.8 to 4.5 MeV with broad resolutions. Differential-neutron-elastic-scattering cross sections are measured from 1.5 to 4.0 MeV at intervals of 50 to 200 keV and at scattering angles distributed between 20 and 160 degrees. Lumped-level neutron-inelastic-scattering cross sections are measured over the same angular and energy range. The exPerimental results are discussed in terms of an optical-statistical model and are compared with respective values given in ENDF/B-V
A method for measuring light ion reaction cross-sections
Carlson, R.F.; Ingemarsson, A.; Lantz, M.; Arendse, G.J.; Auce, A.; Cox, A.J.; Foertsch, S.V.; Jacobs, N.M.; Johansson, R.; Nyberg, J.; Peavy, J.; Renberg, P.-U.; Sundberg, O.; Stander, J.A.; Steyn, G.F.; Tibell, G.; Zorro, R.
2005-01-01
An experimental procedure for measuring reaction cross-sections of light ions in the energy range 20-50 MeV/nucleon, using a modified attenuation technique, is described. The detection method incorporates a forward detector that simultaneously measures the reaction cross-sections for five different sizes of the solid angle in steps from 99.1% to 99.8% of the total solid angle. The final reaction cross-section values are obtained by extrapolation to the full solid angle
Testing of cross section libraries for TRIGA criticality benchmark
Snoj, L.; Trkov, A.; Ravnik, M.
2007-01-01
Influence of various up-to-date cross section libraries on the multiplication factor of TRIGA benchmark as well as the influence of fuel composition on the multiplication factor of the system composed of various types of TRIGA fuel elements was investigated. It was observed that keff calculated by using the ENDF/B VII cross section library is systematically higher than using the ENDF/B-VI cross section library. The main contributions (∼ 2 20 pcm) are from 235 U and Zr. (author)
Evaluation of fusion-evaporation cross-section calculations
Blank, B.; Canchel, G.; Seis, F.; Delahaye, P.
2018-02-01
Calculated fusion-evaporation cross sections from five different codes are compared to experimental data. The present comparison extents over a large range of nuclei and isotopic chains to investigate the evolution of experimental and calculated cross sections. All models more or less overestimate the experimental cross sections. We found reasonable agreement by using the geometrical average of the five model calculations and dividing the average by a factor of 11.2. More refined analyses are made for example for the 100Sn region.
Comparison of {sup 235}U fission cross sections in JENDL-3.3 and ENDF/B-VI
Kawano, Toshihiko [Kyushu Univ., Fukuoka (Japan); Carlson, Allan D. [National Institute of Standards and Technology (United States); Matsunobu, Hiroyuki [Data Engineering, Inc., Fujisawa, Kanagawa (Japan); Nakagawa, Tsuneo; Shibata, Keiichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Talou, Patrick; Young, Philip G.; Chadwick, Mark B. [Los Alamos National Laboratory, Los Alamos, NM (United States)
2002-01-01
Comparisons of evaluated fission cross sections for {sup 235}U in JENDL-3.3 and ENDF/B-VI are carried out. The comparisons are made for both the differential and integral data. The fission cross sections as well as the fission ratios are compared with the experimental data in detail. Spectrum averaged cross sections are calculated and compared with the measurements. The employed spectra are the {sup 235}U prompt fission neutron spectrum, the {sup 252}Cf spontaneous fission neutron spectrum, and the neutron spectrum produced by a {sup 9}Be(d, xn) reaction. For {sup 235}U prompt fission neutron spectrum, the ENDF/B-VI evaluation reproduces experimental averaged cross sections. For {sup 252}Cf and {sup 9}Be(d, xn) neutron spectra, the JENDL-3.3 evaluation gives better results than ENDF/B-VI. (author)
Comparison of 235U fission cross sections in JENDL-3.3 and ENDF/B-VI
Kawano, Toshihiko; Carlson, Allan D.; Matsunobu, Hiroyuki; Nakagawa, Tsuneo; Shibata, Keiichi
2002-01-01
Comparisons of evaluated fission cross sections for 235 U in JENDL-3.3 and ENDF/B-VI are carried out. The comparisons are made for both the differential and integral data. The fission cross sections as well as the fission ratios are compared with the experimental data in detail. Spectrum averaged cross sections are calculated and compared with the measurements. The employed spectra are the 235 U prompt fission neutron spectrum, the 252 Cf spontaneous fission neutron spectrum, and the neutron spectrum produced by a 9 Be(d, xn) reaction. For 235 U prompt fission neutron spectrum, the ENDF/B-VI evaluation reproduces experimental averaged cross sections. For 252 Cf and 9 Be(d, xn) neutron spectra, the JENDL-3.3 evaluation gives better results than ENDF/B-VI. (author)
Green, L.
1976-11-01
The shape of the thorium absorption cross section near thermal energies was investigated. This shape is dominated by one or more negative energy resonances whose parameters are not directly known, but must be inferred from higher energy data. Since the integral quantity most conveniently describing the thermal cross section shape is the Westcottg-factor, effort was directed toward establishing this quantity to high precision. Three nearly independent g-factor estimates were obtained from measurements on a variety of foils in three different neutron spectra provided by polyethylene-moderated neutrons from a 252 Cf source and from irradiations in the National Bureau of Standards ''Standard Thermal Neutron Density.'' The weighted average of the three measurements was 0.993 +- 0.004. This is in good agreement with two recent evaluations and supports the adequacy of the current cross section descriptions
Valence shell photoionization energies and cross-sections of NF sub 3 and PF sub 3
Jürgensen, A
2003-01-01
Relative outer valence shell ionization potentials and cross-sections were determined for the isostructural, Group 15, trifluorides NF sub 3 and PF sub 3 in the gas phase using synchrotron radiation. Excitation photon energies ranged from 70 to 160 eV. The experimental spectra were assigned and cross-sections analyzed with the aid of both MS-X alpha and ab initio calculations. Spectral differences in peak energies and relative intensities are related to structural and electronic differences between these two fluoride molecules. Valence shell ionization potentials were compared to calculated values obtained by several different methods. The partial photoionization cross-sections for each orbital were obtained as a function of excitation energy and compared to theoretical results obtained with the X alpha method.
Evaluation of neutron cross sections to 40 MeV for 5456Fe
Arthur, E.D.; Young, P.G.
1980-01-01
Cross sections for neutron-induced reactions on 54 56 Fe were calculated by employing several nuclear models: optical, Hauser-Feshbach, preequilibrium and DWBA - in the energy range between 3 and 40 MeV. As a prelude to the calculations, the necessary input parameters were determined or verified through analysis of a large body of experimental data for both neutron- and proton-induced reactions in this mass and energy region. This technique also led to cross sections in which the simultaneous influence of available data types added to their consistency and reliability. Calculated cross sections as well as neutron and gamma-ray emission spectra were incorporated into an ENDF evaluation suitable for use to 40 MeV. 12 figures, 1 table
Talys calculations for evaluation of neutron-induced single-event upset cross sections
Bourselier, Jean-Christophe
2005-08-15
The computer code TALYS has been used to calculate interactions between cosmic-ray neutrons and silicon nuclei with the goal to describe single-event upset (SEU) cross sections in microelectronics devices. Calculations for the Si(n,X) reaction extend over an energy range of 2 to 200 MeV. The obtained energy spectra of the resulting residuals and light-ions have been integrated using several different critical charges as SEU threshold. It is found that the SEU cross section seems largely to be dominated by {sup 28}Si recoils from elastic scattering. Furthermore, the shape of the SEU cross section as a function of the energy of the incoming neutron changes drastically with decreasing critical charge. The results presented in this report stress the importance of performing studies at mono-energetic neutron beams to advance the understanding of the underlying mechanisms causing SEUs.
Talys calculations for evaluation of neutron-induced single-event upset cross sections
Bourselier, Jean-Christophe
2005-08-01
The computer code TALYS has been used to calculate interactions between cosmic-ray neutrons and silicon nuclei with the goal to describe single-event upset (SEU) cross sections in microelectronics devices. Calculations for the Si(n,X) reaction extend over an energy range of 2 to 200 MeV. The obtained energy spectra of the resulting residuals and light-ions have been integrated using several different critical charges as SEU threshold. It is found that the SEU cross section seems largely to be dominated by 28 Si recoils from elastic scattering. Furthermore, the shape of the SEU cross section as a function of the energy of the incoming neutron changes drastically with decreasing critical charge. The results presented in this report stress the importance of performing studies at mono-energetic neutron beams to advance the understanding of the underlying mechanisms causing SEUs
Damage cross sections for fast heavy ion induced desorption of biomolecules
Salehpour, M; Hakansson, P; Sundqvist, B [Uppsala Univ. (Sweden). Tandem Accelerator Lab.
1984-03-01
The Uppsala EN-tandem accelerator combined with a time-of-flight mass spectrometer has been used to measure the damage cross sections for Fast Heavy Ion Induced Desorption (FHIID) of the amino acid valine (MW=117) and the protein bovine insulin (MW=5733). Time-of-flight spectra have been obtained after exposing the sample to a known radiation dose of 90 MeV /sup 127/I/sup 14 +/ ions and the yield of the quasi-molecular ions has been measured as a function of the radiation dose. The results are: 6.8(+-1.8)x10/sup -13/ cm/sup 2/ and 50(+-17)x10/sup -13/ cm/sup 2/ for positive ions of valine and insulin respectively. The cross section for valine is roughly one order of magnitude larger than previously published low energy (keV) damage cross sections for the amino acid leucine.
Cross-Sectional Analysis of Longitudinal Mediation Processes.
O'Laughlin, Kristine D; Martin, Monica J; Ferrer, Emilio
2018-01-01
Statistical mediation analysis can help to identify and explain the mechanisms behind psychological processes. Examining a set of variables for mediation effects is a ubiquitous process in the social sciences literature; however, despite evidence suggesting that cross-sectional data can misrepresent the mediation of longitudinal processes, cross-sectional analyses continue to be used in this manner. Alternative longitudinal mediation models, including those rooted in a structural equation modeling framework (cross-lagged panel, latent growth curve, and latent difference score models) are currently available and may provide a better representation of mediation processes for longitudinal data. The purpose of this paper is twofold: first, we provide a comparison of cross-sectional and longitudinal mediation models; second, we advocate using models to evaluate mediation effects that capture the temporal sequence of the process under study. Two separate empirical examples are presented to illustrate differences in the conclusions drawn from cross-sectional and longitudinal mediation analyses. Findings from these examples yielded substantial differences in interpretations between the cross-sectional and longitudinal mediation models considered here. Based on these observations, researchers should use caution when attempting to use cross-sectional data in place of longitudinal data for mediation analyses.
Absolute photoionization cross-section measurements of the Kr I isoelectronic sequence
Kilbane, D.; Banahan, C.; Kampen, P. van; Costello, J. T.; Folkmann, F.; Kjeldsen, H.; Bizau, J.-M.; Scully, S.; Mansfield, M. W. D.; West, J. B.
2007-01-01
Photoionization spectra have been recorded in the 4s, 4p, and 3d resonance regions for the Kr I isoelectronic sequence using both the dual laser produced plasma (DLP) technique (at DCU) to produce photoabsorption spectra, and the merged ion beam and synchrotron radiation technique (at ASTRID) to measure absolute photoionization cross sections. Profile parameters are compared for the 4s-np resonances of Rb + and Sr 2+ . Many 4p→ns, md transitions are identified with the aid of Hartree-Fock calculations, and consistent quantum defects are observed for the various ns and md Rydberg series. Absolute single and double photoionization cross sections recorded in the 3d region for Rb + and Sr 2+ ions show preferential decay via double photoionization. This is only the second report to our knowledge where both the DLP technique and the merged-beam technique have been used simultaneously to record photoionization spectra, and the advantages of both techniques (i.e., better resolution in the case of DLP and values for absolute photoionization cross sections in the case of the merged-beam technique) are highlighted
Measurement of differential (n,x{alpha}) cross section using 4{pi} gridded ionization chamber
Sanami, Toshiya; Baba, Mamoru; Matsuyama, Shigeo; Kiyosumi, Takehide; Nauchi, Yasushi; Saito, Keiichiro; Hirakawa, Naohiro [Tohoku Univ., Sendai (Japan). Faculty of Engineering; Kawano, Toshihiko
1997-03-01
We carried out the measurements of high resolution {alpha} emission spectra of {sup 58}Ni and {sup nat}Ni between 4.5 and 6.5 MeV, and {sup 12}C(n,x{alpha}) cross section using a 4{pi} gridded ionization chamber. In Ni measurement, overall energy resolution was improved to around 200 keV by optimizing a sample thickness and a neutron source width. Measured alpha spectra showed separate peaks corresponding to the ground and low-lying excited states of the residual nucleus ({sup 55}Fe). These results were compared with another direct measurement and statistical model calculations. In {sup 12}C measurement, GIC was applied for (n,x{alpha}) reactions of light nuclei. This application is difficult to (n,x{alpha}) cross sections of light nuclei, because of the influences of large recoil energy and multi-body break-up. We developed new methods which eliminate the effects of recoil nuclei and multi-body break-up and applied them to {sup 12}C(n,x{alpha}) reaction at En=14.1 MeV. In our experiment, the {sup 12}C(n,{alpha}{sub 0}){sup 9}Be angular differential cross section and {sup 12}C(n,n`3{alpha}) cross section were obtained. (author)
Risterucci, P., E-mail: paul.risterucci@gmail.com [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Université de Lyon, Institut des Nanotechnologies de Lyon, 36 avenue Guy de Collongue, 69134 Ecully (France); Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense M (Denmark); Renault, O., E-mail: olivier.renault@cea.fr [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Zborowski, C. [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Sorbonne Universités, UPMC Univ. Paris 06, CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, F-75005, Paris (France); Université de Lyon, Institut des Nanotechnologies de Lyon, 36 avenue Guy de Collongue, 69134 Ecully (France); Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense M (Denmark); Bertrand, D.; Torres, A. [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Rueff, J.-P. [Synchrotron SOLEIL, L' Orme des Merisiers Saint-Aubin, BP 48 91192, Gif-sur-Yvette Cedex (France); Sorbonne Universités, UPMC Univ. Paris 06, CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, F-75005, Paris (France); Ceolin, D. [Synchrotron SOLEIL, L' Orme des Merisiers Saint-Aubin, BP 48 91192, Gif-sur-Yvette Cedex (France); Grenet, G. [Université de Lyon, Institut des Nanotechnologies de Lyon, 36 avenue Guy de Collongue, 69134 Ecully (France); Tougaard, S. [Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense M (Denmark)
2017-04-30
Highlights: • An effective approach for quantitative background analysis in HAXPES spectra of buried layer underneath complex overlayer structures is proposed. • The approach relies on using a weighted sum of inelastic scattering cross section of the pure layers. • The method is validated by the study of an advanced power transistor stack after successive annealing steps. • The depth distribution of crucial elements (Ti, Ga) is determined reliably at depths up to nearly 50 nm. - Abstract: Inelastic background analysis of HAXPES spectra was recently introduced as a powerful method to get access to the elemental distribution in deeply buried layers or interfaces, at depth up to 60 nm below the surface. However the accuracy of the analysis highly relies on suitable scattering cross-sections able to describe effectively the transport of photoelectrons through overlayer structures consisting of individual layers with potentially very different scattering properties. Here, we show that within Tougaard’s practical framework as implemented in the Quases-Analyze software, the photoelectron transport through thick (25–40 nm) multi-layer structures with widely different cross-sections can be reliably described with an effective cross-section in the form of a weighted sum of the individual cross-section of each layer. The high-resolution core-level analysis partly provides a guide for determining the nature of the individual cross-sections to be used. We illustrate this novel approach with the practical case of a top Al/Ti bilayer structure in an AlGaN/GaN power transistor device stack before and after sucessive annealing treatments. The analysis provides reliable insights on the Ti and Ga depth distributions up to nearly 50 nm below the surface.
Total cross-section measurements progress in nuclear physics
Giacomelli, G; Mulvey, J H
2013-01-01
Total Cross-Section Measurements discusses the cross-sectional dimensions of elementary hadron collisions. The main coverage of the book is the resonance and high energy area of the given collision. A section of the book explains in detail the characteristic of a resonance region. Another section is focused on the location of the high energy region of collision. Parts of the book define the meaning of resonance in nuclear physics. Also explained are the measurement of resonance and the identification of the area where the resonance originates. Different experimental methods to measure the tota
Total cross sections for positron and electron scattering from pyrimidine
Zecca, A; Chiari, L; Trainotti, E; GarcIa, G; Blanco, F; Brunger, M J
2010-01-01
In this paper we report original measurements of total cross sections for positron scattering from the important biomolecule pyrimidine. The energy range of these measurements was 0.3-45 eV, while the energy resolution was ∼260 meV. In addition, we report theoretical results, calculated within the independent atom-screened additivity rule (IAM-SCAR) formalism, for the corresponding electron impact total cross sections. In that case the energy range is 1-10 000 eV. Total cross sections are very important input data for codes that seek to simulate charged-particle tracks in matter, as they define the mean-free path between collisions. As the present data and computations are to the best of our knowledge the first total cross sections to be reported for either positron or electron scattering from pyrimidine, they fill an important void in our available knowledge in the literature.
Handbook of LHC Higgs Cross Sections: 2. Differential Distributions
Dittmaier, S; Passarino, G; Tanaka, R; Alekhin, S; Alwall, J; Bagnaschi, E A; Banfi, A; Blumlein, J; Bolognesi, S; Chanon, N; Cheng, T; Cieri, L; Cooper-Sarkar, A M; Cutajar, M; Dawson, S; Davies, G; De Filippis, N; Degrassi, G; Denner, A; D'Enterria, D; Diglio, S; Di Micco, B; Di Nardo, R; Ellis, R K; Farilla, A; Farrington, S; Felcini, M; Ferrera, G; Flechl, M; de Florian, D; Forte, S; Ganjour, S; Garzelli, M V; Gascon-Shotkin, S; Glazov, S; Goria, S; Grazzini, M; Guillet, J -Ph; Hackstein, C; Hamilton, K; Harlander, R; Hauru, M; Heinemeyer, S; Hoche, S; Huston, J; Jackson, C; Jimenez-Delgado, P; Jorgensen, M D; Kado, M; Kallweit, S; Kardos, A; Kauer, N; Kim, H; Kovac, M; Kramer, M; Krauss, F; Kuo, C -M; Lehti, S; Li, Q; Lorenzo, N; Maltoni, F; Mellado, B; Moch, S O; Muck, A; Muhlleitner, M; Nadolsky, P; Nason, P; Neu, C; Nikitenko, A; Oleari, C; Olsen, J; Palmer, S; Paganis, S; Papadopoulos, C G; Petersen, T C; Petriello, F; Petrucci, F; Piacquadio, G; Pilon, E; Potter, C T; Price, J; Puljak, I; Quayle, W; Radescu, V; Rebuzzi, D; Reina, L; Rojo, J; Rosco, D; Salam, G P; Sapronov, A; Schaarschmidt, J; Schonherr, M; Schumacher, M; Siegert, F; Slavich, P; Spira, M; Stewart, I W; Stirling, W J; Stockli, F; Sturm, C; Tackmann, F J; Thorne, R S; Tommasini, D; Torrielli, P; Tramontano, F; Trocsanyi, Z; Ubiali, M; Uccirati, S; Acosta, M Vazquez; Vickey, T; Vicini, A; Waalewijn, W J; Wackeroth, D; Warsinsky, M; Weber, M; Wiesemann, M; Weiglein, G; Yu, J; Zanderighi, G
2012-01-01
This Report summarises the results of the second year's activities of the LHC Higgs Cross Section Working Group. The main goal of the working group was to present the state of the art of Higgs Physics at the LHC, integrating all new results that have appeared in the last few years. The first working group report Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002) focuses on predictions (central values and errors) for total Higgs production cross sections and Higgs branching ratios in the Standard Model and its minimal supersymmetric extension, covering also related issues such as Monte Carlo generators, parton distribution functions, and pseudo-observables. This second Report represents the next natural step towards realistic predictions upon providing results on cross sections with benchmark cuts, differential distributions, details of specific decay channels, and further recent developments.
Fully differential cross sections for heavy particle impact ionization
McGovern, M; Walters, H R J [Department of Applied Mathematics and Theoretical Physics, Queen' s University, Belfast BT7 1NN (United Kingdom); Assafrao, D; Mohallem, J R [Laboratorio de Atomos e Moleculas Especiais, Departamento de Fisica, ICEx, Universidade Federal de Minas Gerais, P.O Box 702, 30123-970 Belo Horizonte, MG (Brazil); Whelan, Colm T, E-mail: mmcgovern06@qub.ac.u [Department of Physics, Old Dominion University, Norfolk, VA 23529-0116 (United States)
2009-11-15
We describe a procedure for extracting fully differential ionization cross sections from an impact parameter coupled pseudostate treatment of the collision. Some examples from antiproton impact ionization of atomic Hydrogen are given.
Theoretical Studies on Photoionization Cross Sections of Solid Gold
Ma Xiaoguang; Sun Weiguo; Cheng Yansong
2005-01-01
Accurate expression for photoabsorption (photoionization) cross sections of high density system proposed recently is used to study the photoionization of solid gold. The results show that the present theoretical photoionization cross sections have good agreement both in structure and in magnitude with the experimental results of gold crystal. The studies also indicate that both the real part ε' and the imaginary part ε'' of the complex dielectric constant ε, and the dielectric influence function of a nonideal system have rich structures in low energy side with a range about 50 eV, and suggest that the influence of particle interactions of surrounding particles with the photoionized particle on the photoionization cross sections can be easily investigated using the dielectric influence function. The electron overlap effects are suggested to be implemented in the future studies to improve the accuracy of theoretical photoionization cross sections of a solid system.
Models for Photon-photon Total Cross-sections
Godbole, RM; Grau, A; Pancheri, G
1999-01-01
We present here a brief overview of recent models describing the photon-photon cross-section into hadrons. We shall show in detail results from the eikonal minijet model, with and without soft gluon summation.
Highlights of top quark cross-section measurements at ATLAS
Berta Peter
2017-01-01
Full Text Available The highlights of the measurements of top quark production in proton-proton collisions at the Large Hadron Collider with the ATLAS detector are presented. The inclusive measurements of the top-pair production cross section have reached high precision and are compared to the best available theoretical calculations. The differential cross section measurements, including results using boosted top quarks, probe our understanding of top-pair production in the TeV regime. The results are compared to Monte Carlo generators implementing LO and NLO matrix elements matched with parton showers. Measurements of the single top quark production cross section are presented in the t-channel and s-channel, and with associated production with a W boson. For the t-channel production, results on the ratio between top quark and antitop quark production cross sections and differential measurements are also included.
Total and partial recombination cross sections for F6+
Mitnik, D.M.; Pindzola, M.S.; Badnell, N.R.
1999-01-01
Total and partial recombination cross sections for F 6+ are calculated using close-coupling and distorted-wave theory. For total cross sections, close-coupling and distorted-wave results, which include interference between the radiative and dielectronic pathways, are found to be in good agreement with distorted-wave results based on a sum of independent processes. Total cross sections near zero energy are dominated by contributions from low-energy dielectronic recombination resonances. For partial cross sections, the close-coupling and distorted-wave theories predict strong interference for recombination into the final recombined ground state 1s 2 2s 21 S 0 of F 5+ , but only weak interference for recombination into the levels of the 1s 2 2s2p configuration. copyright 1999 The American Physical Society
New neutron cross sections for fusion materials studies
Greenwood, L.R.; Smither, R.K.
1985-01-01
Neutron cross sections are being developed for a variety of fusion-related applications including neutron dosimetry, fusion plasma diagnostics, the activation of very long-lived isotopes, and high-energy accelerator neutron sources
Density dependence of stopping cross sections measured in liquid ethane
Both, G.; Krotz, R.; Lohmer, K.; Neuwirth, W.
1983-01-01
Electronic stopping cross sections for 7 Li projectiles (840--175 keV) have been measured with the inverted Doppler-shift attenuation method in liquid ethane (C 2 H 6 ) at two different densities. The density of the target has been varied by changing the temperature, and measurements have been performed at 0.525 g/cm 3 (199 K) and 0.362 g/cm 3 (287 K). At the higher density the stopping cross section is about 2% smaller. This result agrees with a calculation of the stopping cross section of liquid ethane, applying Lindhard's theory in the local-density approximation using a simple model of the liquid. It is also in agreement with various observations of the so-called physical-state effect, which show that the stopping cross section of the same substance is smaller in a condensed phase than in the gaseous one
Some sources of the underestimation of evaluated cross section uncertainties
Badikov, S.A.; Gai, E.V.
2003-01-01
The problem of the underestimation of evaluated cross-section uncertainties is addressed. Two basic sources of the underestimation of evaluated cross-section uncertainties - a) inconsistency between declared and observable experimental uncertainties and b) inadequacy between applied statistical models and processed experimental data - are considered. Both the sources of the underestimation are mainly a consequence of existence of the uncertainties unrecognized by experimenters. A model of a 'constant shift' is proposed for taking unrecognised experimental uncertainties into account. The model is applied for statistical analysis of the 238 U(n,f)/ 235 U(n,f) reaction cross-section ratio measurements. It is demonstrated that multiplication by sqrt(χ 2 ) as instrument for correction of underestimated evaluated cross-section uncertainties fails in case of correlated measurements. It is shown that arbitrary assignment of uncertainties and correlation in a simple least squares fit of two correlated measurements of unknown mean leads to physically incorrect evaluated results. (author)
Nonelastic-scattering cross sections of elemental nickel
Smith, A.B.; Guenther, P.T.; Whalen, J.F.
1980-06-01
Neutron total cross sections of elemental nickel were measured from 1.3 to 4.5 MeV, at intervals of approx. 50 keV, with resolutions of 30 to 50 keV and to accuracies of 1 to 2.5%. Neutron differential-elastic-scattering cross sections were measured from 1.45 to 3.8 MeV, at intervals and with resolutions comparable to those of the total cross sections, and to accuracies of 3 to 5%. The nonelastic-scattering cross section is derived from the measured values to accuracies of greater than or equal to 6%. The experimental results are compared with previously reported values as represented by ENDF/B-V, and areas of consistency and discrepancy, noted. The measured results are shown to be in good agreement with the predictions of a model previously reported by the authors. 4 figures, 1 table
Charge exchange cross-sections for multiply charged ions
Midha, J.M.; Gupta, S.C.
1990-01-01
A new empirical relation for charge exchange cross-section has been proposed for different charge states of C, N and O colliding with neutral hydrogen. Results are compared with the experimental data. (Author)
Advantages and disadvantages : longitudinal vs. repeated cross-section surveys
1996-06-20
The benefits of a longitudinal analysis over a repeated cross-sectional study include increased statistical power and the capability to estimate a greater range of conditional probabilities. With the Puget Sound Transportation Panel (PSTP), and any s...
Some problem areas in capture cross-section measurements
Moxon, M.C.; Gayther, D.B.; Sowerby, M.G.
1975-01-01
This paper outlines some of the problems that have been encountered and are envisaged in the measurement and evaluation of capture cross-sections. Particular emphasis is placed on the cross-sections of the structural materials (Fe, Ni, Cr) used in fast reactors. The topics considered are the influence of scattered neutrons in capture detectors, the determination of background, sample thickness corrections, and the theoretical representation of resonance parameters. (author)
100 group displacement cross sections from RECOIL data base
Gopalakrishnan, V.
1995-01-01
Displacement cross sections in 100 neutron energy groups were calculated from the RECOIL data base using the RECOIL program, for use in DPA (Displacement Per Atom) calculations for FBTR and PFBR materials. 100 group displacement cross sections were calculated using RECOIL-Data Base and RECOIL Program. Modifications were made in the data base to reduce space requirement, and in the program for easy handling on a PC. 2 refs
Scattering cross-section of an inhomogeneous plasma cylinder
Jiaming Shi; Lijian Qiu; Ling, Y.
1995-01-01
Scattering of em waves by the plasma cylinder is of significance in radar target detection, plasma diagnosis, etc. This paper discusses the general method to calculate the scattering cross-section of em waves from a plasma cylinder which is radially inhomogeneous and infinitely long. Numerical results are also provided for several plasma density profiles. The effect of the electron density distribution on the scattering cross-section is investigated
Photoneutron cross sections for D2O and beryllium
Bowsher, H.F.; Woods, F.J.; Baumann, N.P.
1975-01-01
The photodissociation cross section by 24 Na gamma rays was measured for deuterium in order to resolve a discrepancy between earlier measurements (1.43 to 1.59 millibarns) and a more recently reported one (1.34 mb). The measurement of the beryllium (γ,n) cross section for 24 Na gamma rays was also included as a check. Results for deuterium (1.54 mb) are in agreement with the earlier values
Neutron capture cross section standards for BNL 325, Fourth Edition
Holden, N.E.
1981-01-01
This report evaluates the experimental data and recommends values for the thermal neutron cross sections and resonance integrals for the neutron capture reactions: 55 Mn(n,γ), 59 Co(n,γ) and 197 Au(n,γ). The failure of lithium and boron as standards due to the natural variation of the absorption cross sections of these elements is discussed. The Westcott convention, which describes the neutron spectrum as a thermal Maxwellian distribution with an epithermal component, is also discussed
Electromagnetic-gravitational conversion cross sections in external electromagnetic fields
Hoang Ngoc Long; Dang Van Soa; Tuan Tran, A.
1994-09-01
The classical processes: the conversion of photons into gravitons in the static electromagnetic fields are considered by using Feynman perturbation techniques. The differential cross sections are presented for the conversion in the electric field of the flat condenser and the magnetic field of the solenoid. A numerical evaluation shows that the cross sections may have the observable value in the present technical scenario. (author). 11 refs
The γ total cross section and the photon structure functions
Alexander, G.
1986-01-01
A review on the current experimental status of the photon-photon total hadronic cross section as a function of energy and Q 2 is given in addition to the results obtained for the leptonic and hadronic photon structure functions. The results are discussed in terms of the point-like part of the photon and non-perturbative VDM part. It is shown that the cross section at Q 2 = 0 is well described by VDM derived models
Determination of molecular ionization cross sections in an ICR spectrometer
Takashima, K.; Riveros, J.M.
1976-01-01
Ionization cross sections have been determined for simple gases at 75eV in an ICR spectrometer. Results obtained using a calibrated ion gauge as a pressure indicator yield values which are consistently higher than accepted values by as much as 15%. These results suggest that a more convenient way to measure pressure in ICR experiments might be to record the total ion current and to use the tabulated ionization cross sections where available [pt
Cross section recondensation method via generalized energy condensation theory
Douglass, Steven; Rahnema, Farzad
2011-01-01
Highlights: → A new method is presented which corrects for core environment error from specular boundaries at the lattice cell level. → Solution obtained with generalized energy condensation provides improved approximation to the core level fine-group flux. → Iterative recondensation of the cross sections and unfolding of the flux provides on-the-fly updating of the core cross sections. → Precomputation of energy integrals and fine-group cross sections allows for easy implementation and efficient solution. → Method has been implemented in 1D and shown to correct the environment error, particularly in strongly heterogeneous cores. - Abstract: The standard multigroup method used in whole-core reactor analysis relies on energy condensed (coarse-group) cross sections generated from single lattice cell calculations, typically with specular reflective boundary conditions. Because these boundary conditions are an approximation and not representative of the core environment for that lattice, an error is introduced in the core solution (both eigenvalue and flux). As current and next generation reactors trend toward increasing assembly and core heterogeneity, this error becomes more significant. The method presented here corrects for this error by generating updated coarse-group cross sections on-the-fly within whole-core reactor calculations without resorting to additional cell calculations. In this paper, the fine-group core flux is unfolded by making use of the recently published Generalized Condensation Theory and the cross sections are recondensed at the whole-core level. By iteratively performing this recondensation, an improved core solution is found in which the core-environment has been fully taken into account. This recondensation method is both easy to implement and computationally very efficient because it requires precomputation and storage of only the energy integrals and fine-group cross sections. In this work, the theoretical basis and development
Triply differential cross sections for ionization of helium by electrons
Brauner, M.; Briggs, J.S.; Broad, J.T.
1991-01-01
A correlated three-body continuum wavefunction, already successfully employed to describe hydrogen atom impact ionization, is used to calculate the triply-differential cross section for electron impact ionization of helium. A good description is obtained of all the major structure in the differential cross sections in both symmetric and asymmetric geometries. It is demonstrated how interference between the various projectile-target interactions is necessary to reproduce the experimentally observed structure. (author)
Cross section and linear polarization of tagged photons
Asai, J.; Caplan, H.S.; Skopik, D.M.; DelBianco, W.; Maximon, L.C.
1988-01-01
Formulae for bremsstrahlung cross sections and polarizations are usually presented in coordinate systems not very suitable for application by experimental physicists to devices such as photon-tagging monochromators. In this paper the transformations between the different coordinate systems are presented, along with examples of the calculated cross sections and polarizations in a form convenient from the experimental standpoint. These examples also give the predicted characteristics of the photon tagger currently under construction at the Saskatchewan Accelerator Laboratory. (16 refs., 19 figs., tab.)
Differential cross sections for neutrino scattering on 12C
Kolbe, E.
1996-01-01
Differential cross sections for neutrino scattering on 12 C are calculated within the (continuum) random phase approximation model. The charged current (ν e ,e - ) and (ν μ ,μ - ) capture reactions on 12 C are measured by the LSND Collaboration at LAMPF. We investigate and discuss the merits of such studies, especially the information that can be extracted from data for differential neutrino scattering cross sections. copyright 1996 The American Physical Society
Low energy total cross section of 36Ar
Mughabghab, S.F.; Magurno, B.A.
1975-01-01
To compare the predictions of the valence model with measured partial radiative widths of 36 Ar an accurate knowledge of the bound-level parameters is required. This is achieved by carrying out a Breit-Wigner parameter fit to the total cross section of 36 Ar measured by Chrien et al and renormalized to the recommended values of the thermal capture and scattering cross sections. (1 figure, 1 table) (U.S.)
Measurements of the electron and muon inclusive cross-sections
We present the measurements of the differential cross-sections for inclusive electron and muon production in proton–proton collisions at a centre-of-mass energy of s = 7 TeV, using ∼ 1.4 pb-1 of data collected by the ATLAS detector at the Large Hadron Collider. The muon cross-section is measured as a function of muon ...
MINERvA - neutrino nucleus cross section experiment
CERN. Geneva
2014-01-01
Recent results from MINERvA, a neutrino cross section experiment at Fermilab, are presented. MINERVA has the goal of providing precision results which will have important impact on oscillation experiments. Initial data runs for muon neutrino and antineutrino beams of ~3.5 GeV have produced a large number of new results. This seminar will introduce the experiment and describe results for quasielastic, pion production, and inclusive cross sections.
Augmented Cross-Sectional Prevalence Testing for Estimating HIV Incidence
Wang, R.; Lagakos, S. W.
2010-01-01
Estimation of an HIV incidence rate based on a cross-sectional sample of individuals evaluated with both a sensitive and less-sensitive diagnostic test offers important advantages to incidence estimation based on a longitudinal cohort study. However, the reliability of the cross-sectional approach has been called into question because of two major concerns. One is the difficulty in obtaining a reliable external approximation for the mean “window period” between detectability of HIV infection ...
An Ada environment for relativistic cross section calculations
Nilsson, E.
1990-01-01
We have developed an Ada environment adapted to relativistic cross section calculations. Objects such as four-vectors, γ- matrices and propagators are defined as well as operations between these objects. In this environment matrix elements can be expressed in a compact and readable way as Ada code. Unpolarized cross sections are calculated numerically by explicitly summing and averaging over spins and polarizations. A short presentation of the technique is given
Cross sections of the interactions of He nuclei with protons
Glagolev, V.V.; Lebedev, R.M.; Pestova, G.D.; Shimansky, S.S.; Kravcikova, M.; Seman, M.; Sandor, L.; Dirner, A.; Hlavacova, J.; Martinska, G.; Urban, J.; Khairetdinov, K.U.; Braun, H.; Gerber, J.P.; Juillot, P.; Michalon, A.; Kacharava, A.K.; Menteshashvili, Z.P.; Nioradze, M.S.; Salukvadze, Z.R.; Sobczak, T.; Stepaniak, J.
1993-01-01
4 He-p collisions at two values of 4 He momenta 8.6 GeV/c and 13.6 GeV/c as well as the 3 He-p collisions at 13.5 GeV/c have been studied using the one-meter JINR hydrogen bubble chamber. Total, elastic, topological and reaction cross sections have been measured. The cross sections have been determined on a sample of minimum biased events. (orig.)
Summary of activation cross section measurements at FNS
Ikeda, Y.; Konno, C.; Kasugai, Y.; Kumar, A.
1996-01-01
Neutron activation cross sections around 14 MeV for seventeen reactions have been measured at the FNS facility in JAERI in order to provide experimental data meeting the requirement in the radioactive wastes disposal assessment in the D-T fusion reactor. This report summarizes contributing data measured in several phases of experiments to the IAEA-CRP on ''Activation Cross sections for the Generation of Long-Lived radionuclides of Importance in Fusion Reactor Technology''. (author). 18 refs, 1 tab
Ideal gas scattering kernel for energy dependent cross-sections
Rothenstein, W.; Dagan, R.
1998-01-01
A third, and final, paper on the calculation of the joint kernel for neutron scattering by an ideal gas in thermal agitation is presented, when the scattering cross-section is energy dependent. The kernel is a function of the neutron energy after scattering, and of the cosine of the scattering angle, as in the case of the ideal gas kernel for a constant bound atom scattering cross-section. The final expression is suitable for numerical calculations
Thermal neutron capture cross sections of tellurium isotopes
Tomandl, I.; Honzatko, J.; Egidy, T. von; Wirth, H.-F.; Belgya, T.; Lakatos, M.; Szentmiklosi, L.; Revay, Zs.; Molnar, G.L.; Firestone, R.B.; Bondarenko, V.
2003-01-01
New values for thermal neutron capture cross sections of the tellurium isotopes 122 Te, 124 Te, 125 Te, 126 Te, 128 Te, and 130 Te are reported. These values are based on a combination of newly determined partial γ-ray cross sections obtained from experiments on targets contained natural Te and γ intensities per capture of individual Te isotopes. Isomeric ratios for the thermal neutron capture on the even tellurium isotopes are also given
Thermal neutron capture cross sections of tellurium isotopes
Tomandl, I.; Honzatko, J.; Egidy, T. von; Wirth, H.-F.; Belgya, T.; Lakatos, M.; Szentmiklosi, L.; Revay, Zs.; Molnar, G.L.; Firestone, R.B.; Bondarenko, V.
2004-01-01
New values for thermal neutron capture cross sections of the tellurium isotopes 122Te, 124Te, 125Te, 126Te, 128Te, and 130Te are reported. These values are based on a combination of newly determined partial g-ray cross sections obtained from experiments on targets contained natural Te and gamma intensities per capture of individual Te isotopes. Isomeric ratios for the thermal neutron capture on the even tellurium isotopes are also given
Thermal neutron capture cross sections of tellurium isotopes
Tomandl, I.; Honzatko, J.; von Egidy, T.; Wirth, H.-F.; Belgya, T.; Lakatos, M.; Szentmiklosi, L.; Revay, Zs.; Molnar, G.L.; Firestone, R.B.; Bondarenko, V.
2004-03-01
New values for thermal neutron capture cross sections of the tellurium isotopes 122Te, 124Te, 125Te, 126Te, 128Te, and 130Te are reported. These values are based on a combination of newly determined partial g-ray cross sections obtained from experiments on targets contained natural Te and gamma intensities per capture of individual Te isotopes. Isomeric ratios for the thermal neutron capture on the even tellurium isotopes are also given.
Investigation of the sup 9 sup 3 Nb neutron cross-sections in resonance energy range
Grigoriev, Y V; Faikov-Stanchik, H; Ilchev, G; Kim, G N; Kitaev, V Ya; Mezentseva, Z V; Panteleev, T; Sinitsa, V V; Zhuravlev, B V
2001-01-01
The results of gamma-ray multiplicity spectra and transmission measurements for sup 9 sup 3 Nb in energy range 21.5 eV-100 keV are presented. Gamma spectra from 1 to 7 multiplicity were measured on the 501 m and 121 m flight paths of the IBR-30 using a 16-section scintillation detector with a NaI(Tl) crystals of a total volume of 36 l and a 16-section liquid scintillation detector of a total volume of 80 l for metallic samples of 50, 80 mm in diameter and 1, 1.5 mm thickness with 100% sup 9 sup 3 Nb. Besides, the total and scattering cross-section of sup 9 sup 3 Nb were measured by means batteries of B-10 and He-3 counters on the 124 m, 504 m and 1006 m flight paths of the IBR-30. Spectra of multiplicity distribution were obtained for resolved resonances in the energy region E=30-6000 eV and for energy groups in the energy region E=21.5 eV- 100 keV. They were used for determination of the average multiplicity, resonance parameters and capture cross-section in energy groups and for low-laying resonances of sup...
Calculation of the intermediate energy activation cross section
Furihata, Shiori; Yoshizawa, Nobuaki [Mitsubishi Research Inst., Inc., Tokyo (Japan)
1997-03-01
We discussed the activation cross section in order to predict accurately the activation of soil around an accelerator with high energy and strong intensity beam. For the assessment of the accuracy of activation cross sections estimated by a numerical model, we compared the calculated cross section with various experimental data, for Si(p,x){sup 22}Na, Al(p,x){sup 22}Na, Fe(p,x){sup 22}Na, Si(p,x){sup 7}Be, O(p,x){sup 3}H, Al(p,x){sup 3}H and Si(p,x){sup 3}H reactions. We used three computational codes, i.e., quantum molecular dynamics (QMD) plus statistical decay model (SDM), HETC-3STEP and the semiempirical method developed by Silberberg et.al. It is observed that the codes are accurate above 1GeV, except for {sup 7}Be production. We also discussed the difference between the activation cross sections of proton- and neutron-induced reaction. For the incident energy at 40MeV, it is found that {sup 3}H production cross sections of neutron-induced reaction are ten times as large as those of proton-induced reaction. It is also observed that the choice of the activation cross sections seriously affects to the estimate of saturated radioactivity, if the maximum energy of neutron flux is below 100MeV. (author)
Asymptotic behaviour of pion-pion total cross-sections
Greynat, David; Rafael, Eduardo de; Vulvert, Grégory
2014-01-01
We derive a sum rule which shows that the Froissart-Martin bound for the asymptotic behaviour of the ππ total cross sections at high energies, if modulated by the Lukaszuk-Martin coefficient of the leading log 2 s behaviour, cannot be an optimal bound in QCD. We next compute the total cross sections for π + π − , π ± π 0 and π 0 π 0 scattering within the framework of the constituent chiral quark model (CχQM) in the limit of a large number of colours N c and discuss their asymptotic behaviours. The same ππ cross sections are also discussed within the general framework of Large-N c QCD and we show that it is possible to make an Ansatz for the isospin I=1 and I=0 spectrum which satisfy the Froissart-Martin bound with coefficients which, contrary to the Lukaszuk-Martin coefficient, are not singular in the chiral limit and have the correct Large-N c counting. We finally propose a simple phenomenological model which matches the low energy behaviours of the σ π ± π 0 total (s) cross section predicted by the CχQM with the high energy behaviour predicted by the Large-N c Ansatz. The magnitude of these cross sections at very high energies is of the order of those observed for the pp and pp-bar scattering total cross sections
Development of automatic cross section compilation system for MCNP
Maekawa, Fujio; Sakurai, Kiyoshi
1999-01-01
A development of a code system to automatically convert cross-sections for MCNP is in progress. The NJOY code is, in general, used to convert the data compiled in the ENDF format (Evaluated Nuclear Data Files by BNL) into the cross-section libraries required by various reactor physics codes. While the cross-section library: FSXLIB-J3R2 was already converted from the JENDL-3.2 version of Japanese Evaluated Nuclear Data Library for a continuous energy Monte Carlo code MCNP, the library keeps only the cross-sections at room temperature (300 K). According to the users requirements which want to have cross-sections at higher temperature, say 600 K or 900 K, a code system named 'autonj' is under development to provide a set of cross-section library of arbitrary temperature for the MCNP code. This system can accept any of data formats adopted JENDL that may not be treated by NJOY code. The input preparation that is repeatedly required at every nuclide on NJOY execution is greatly reduced by permitting the conversion process of as many nuclides as the user wants in one execution. A few MCNP runs were achieved for verification purpose by using two libraries FSXLIB-J3R2 and the output of autonj'. The almost identical MCNP results within the statistical errors show the 'autonj' output library is correct. In FY 1998, the system will be completed, and in FY 1999, the user's manual will be published. (K. Tsuchihashi)
Total cross sections for electron scattering by He
De Heer, F.J.; Jansen, R.H.J.
1977-01-01
A set of total cross sections for scattering of electrons by He has been evaluated over the energy range of zero to 3000 eV by means of the analysis of experiments and theories on total cross sections for elastic scattering, ionisation and excitation, and on differential cross sections for elastic and inelastic scattering. Between 0 and 19.8 eV, where no inelastic processes occur, the total cross sections for scattering are equal to those for elastic scattering. Above 19.8 eV total cross sections for scattering of electrons have been evaluated by adding those for ionisation, excitation and elastic scattering. The total cross sections thus obtained are probably accurate to about 5% over a large part of the energy range. They appear to be in very good agreement with the recent experimental results of Blaauw et al. (J. Phys. B.; 10:L299 (1977)). The present results have already proved useful for application in the dispersion relation for forward scattering in electron-helium collisions. (author)
Methodology series module 3: Cross-sectional studies
Maninder Singh Setia
2016-01-01
Full Text Available Cross-sectional study design is a type of observational study design. In a cross-sectional study, the investigator measures the outcome and the exposures in the study participants at the same time. Unlike in case–control studies (participants selected based on the outcome status or cohort studies (participants selected based on the exposure status, the participants in a cross-sectional study are just selected based on the inclusion and exclusion criteria set for the study. Once the participants have been selected for the study, the investigator follows the study to assess the exposure and the outcomes. Cross-sectional designs are used for population-based surveys and to assess the prevalence of diseases in clinic-based samples. These studies can usually be conducted relatively faster and are inexpensive. They may be conducted either before planning a cohort study or a baseline in a cohort study. These types of designs will give us information about the prevalence of outcomes or exposures; this information will be useful for designing the cohort study. However, since this is a 1-time measurement of exposure and outcome, it is difficult to derive causal relationships from cross-sectional analysis. We can estimate the prevalence of disease in cross-sectional studies. Furthermore, we will also be able to estimate the odds ratios to study the association between exposure and the outcomes in this design.
Methodology Series Module 3: Cross-sectional Studies.
Setia, Maninder Singh
2016-01-01
Cross-sectional study design is a type of observational study design. In a cross-sectional study, the investigator measures the outcome and the exposures in the study participants at the same time. Unlike in case-control studies (participants selected based on the outcome status) or cohort studies (participants selected based on the exposure status), the participants in a cross-sectional study are just selected based on the inclusion and exclusion criteria set for the study. Once the participants have been selected for the study, the investigator follows the study to assess the exposure and the outcomes. Cross-sectional designs are used for population-based surveys and to assess the prevalence of diseases in clinic-based samples. These studies can usually be conducted relatively faster and are inexpensive. They may be conducted either before planning a cohort study or a baseline in a cohort study. These types of designs will give us information about the prevalence of outcomes or exposures; this information will be useful for designing the cohort study. However, since this is a 1-time measurement of exposure and outcome, it is difficult to derive causal relationships from cross-sectional analysis. We can estimate the prevalence of disease in cross-sectional studies. Furthermore, we will also be able to estimate the odds ratios to study the association between exposure and the outcomes in this design.
Porosity effects in the neutron total cross section of graphite
Santisteban, J. R; Dawidowski, J; Petriw, S. N
2009-01-01
Graphite has been used in nuclear reactors since the birth of the nuclear industry due to its good performance as a neutron moderator material. Graphite is still an option as moderator for generation IV reactors due to its good mechanical and thermal properties at high operation temperatures. So, there has been renewed interest in a revision of the computer libraries used to describe the neutron cross section of graphite. For sub-thermal neutron energies, polycrystalline graphite shows a larger total cross section (between 4 and 8 barns) than predicted by existing theoretical models (0.2 barns). In order to investigate the origin of this discrepancy we measured the total cross section of graphite samples of three different origins, in the energy range from 0.001 eV to 10 eV. Different experimental arrangements and sample treatments were explored, to identify the effect of various experimental parameters on the total cross section measurement. The experiments showed that the increase in total cross section is due to neutrons scattered around the forward direction. We associate these small-angle scattered neutrons (SANS) to the porous structure of graphite, and formulate a very simple model to compute its contribution to the total cross section of the material. This results in an analytic expression that explicitly depends on the density and mean size of the pores, which can be easily incorporated in nuclear library codes. [es
Hudson, Nathanael Harrison
An accurate and computationally fast method to generate nodal cross sections for the Pebble Bed Reactor (PBR) was presented. In this method, named Spectral History Correction (SHC), a set of fine group microscopic cross section libraries, pre-computed at specified depletion and moderation states, was coupled with the nodal nuclide densities and group bucklings to compute the new fine group spectrum for each node. The relevant fine group cross-section library was then recollapsed to the local broad group cross-section structure with this new fine group spectrum. This library set was tracked in terms of fuel isotopic densities. Fine group modulation factors (to correct the homogeneous flux for heterogeneous effects) and fission spectra were also stored with the cross section library. As the PBR simulation converges to a steady state fuel cycle, the initial nodal cross section library becomes inaccurate due to the burnup of the fuel and the neutron leakage into and out of the node. Because of the recirculation of discharged fuel pebbles with fresh fuel pebbles, a node can consist of a collection of pebbles at various burnup stages. To account for the nodal burnup, the microscopic cross sections were combined with nodal averaged atom densities to approximate the fine group macroscopic cross-sections for that node. These constructed, homogeneous macroscopic cross sections within the node were used to calculate a numerical solution for the fine group spectrum with B1 theory. This new fine spectrum was used to collapse the pre-computed microscopic cross section library to the broad group structure employed by the fuel cycle code. This SHC technique was developed and practically implemented as a subroutine within the PBR fuel cycle code PEBBED. The SHC subroutine was called to recalculate the broad group cross sections during the code convergence. The result was a fast method that compared favorably to the benchmark scheme of cross section calculation with the lattice
Activation cross section and isomeric cross section ratios for the (n ,2 n ) reaction on 153Eu
Luo, Junhua; Jiang, Li; Li, Suyuan
2017-10-01
The 153Eu(n ,2 n ) m1,m2,g152Eu cross section was measured by means of the activation technique at three neutron energies in the range 13-15 MeV. The quasimonoenergetic neutron beam was formed via the 3H(d ,n ) 4He reaction, in the Pd-300 Neutron Generator at the Chinese Academy of Engineering Physics (CAEP). The activities induced in the reaction products were measured using high-resolution γ-ray spectroscopy. The cross section of the population of the second high-spin (8-) isomeric state was measured along with the reaction cross section populating both the ground (3-) and the first isomeric state (0-). Cross sections were also evaluated theoretically using the numerical code TALYS-1.8, with different level density options at neutron energies varying from the reaction threshold to 20 MeV. Results are discussed and compared with the corresponding literature.
Utilization of cross-section covariance data in FBR core nuclear design and cross-section adjustment
Ishikawa, Makoto
1994-01-01
In the core design of large fast breeder reactors (FBRs), it is essentially important to improve the prediction accuracy of nuclear characteristics from the viewpoint of both reducing cost and insuring reliability of the plant. The cross-section errors, that is, covariance data are one of the most dominant sources for the prediction uncertainty of the core parameters, therefore, quantitative evaluation of covariance data is indispensable for FBR core design. The first objective of the present paper is to introduce how the cross-section covariance data are utilized in the FBR core nuclear design works. The second is to delineate the cross-section adjustment study and its application to an FBR design, because this improved design method markedly enhances the needs and importance of the cross-section covariance data. (author)
R. Wagner
2011-09-01
Full Text Available We present computational results on the shape dependency of the extinction and absorption cross sections of dustlike aerosol particles that were modeled as randomly oriented spheroids. Shape dependent variations in the extinction cross sections are largest in the size regime that is governed by the interference structure. Elongated spheroids best fitted measured extinction spectra of re-dispersed Saharan dust samples. For dust particles smaller than 1.5 μm in diameter and low absorption potential, shape effects on the absorption cross sections are very small.
Savin, M.V.; Nefedov, Yu.Ya; Livke, A.V.; Zvenigorodskij, A.G.
2001-01-01
Experimental data on the total gamma-ray production cross-sections for inelastic interaction of fast neutrons with iron nuclei were analysed. The total gamma-ray production cross-sections, grouped according to E γ , were evaluated in the neutron energy range 0.5-19 MeV. The statistical spline approximation method was used to evaluate the experimental data. Evaluated data stored in the ENDF, JENDL, BROND, and other libraries on gamma-ray production spectra and cross-sections for inelastic interaction of fast neutrons with iron nuclei, were analysed. (author)
ACTIV87 Fast neutron activation cross section file 1987
Manokhin, V.N.; Pashchenko, A.B.; Plyaskin, V.I.; Bychkov, V.M.; Pronyaev, V.G.; Schwerer, O.
1989-10-01
This document summarizes the content of the Fast Neutron Activation Cross Section File based on data from different evaluated data libraries and individual evaluations in ENDF/B-5 format. The entire file or selective retrievals from it are available on magnetic tape, free of charge, from the IAEA Nuclear Data Section. (author)
Models for Pooled Time-Series Cross-Section Data
Lawrence E Raffalovich
2015-07-01
Full Text Available Several models are available for the analysis of pooled time-series cross-section (TSCS data, defined as “repeated observations on fixed units” (Beck and Katz 1995. In this paper, we run the following models: (1 a completely pooled model, (2 fixed effects models, and (3 multi-level/hierarchical linear models. To illustrate these models, we use a Generalized Least Squares (GLS estimator with cross-section weights and panel-corrected standard errors (with EViews 8 on the cross-national homicide trends data of forty countries from 1950 to 2005, which we source from published research (Messner et al. 2011. We describe and discuss the similarities and differences between the models, and what information each can contribute to help answer substantive research questions. We conclude with a discussion of how the models we present may help to mitigate validity threats inherent in pooled time-series cross-section data analysis.
Cross-section crushing behaviour of hat-sections (Part II: Analytical modelling)
Hofmeyer, H.
2005-01-01
Hat-sections are often used to experimentally investigate building sheeting subject to a concentrated load and bending. In car doors, hat-sections are used for side-impact protection. Their crushing behaviour can partly be explained by only observing their cross-sectional behaviour [1]. This
Total cross section of furfural by electron impact: Experiment and theory.
Traoré Dubuis, A; Verkhovtsev, A; Ellis-Gibbings, L; Krupa, K; Blanco, F; Jones, D B; Brunger, M J; García, G
2017-08-07
We present experimental total cross sections for electron scattering from furfural in the energy range from 10 to 1000 eV, as measured using a double electrostatic analyzer gas cell electron transmission experiment. These results are compared to theoretical data for furfural, as well as to experimental and theoretical values for the structurally similar molecules furan and tetrahydrofuran. The measured total cross section is in agreement with the theoretical results obtained by means of the independent-atom model with screening corrected additivity rule including interference method. In the region of higher electron energies, from 500 eV to 10 keV, the total electron scattering cross section is also estimated using a semi-empirical model based on the number of electrons and dipole polarizabilities of the molecular targets. Together with the recently measured differential and integral cross sections, and the furfural energy-loss spectra, the present total cross section data nearly complete the data set that is required for numerical simulation of low-energy electron processes in furfural, covering the range of projectile energies from a few electron volts up to 10 keV.
Total cross section of furfural by electron impact: Experiment and theory
Traoré Dubuis, A.; Verkhovtsev, A.; Ellis-Gibbings, L.; Krupa, K.; Blanco, F.; Jones, D. B.; Brunger, M. J.; García, G.
2017-08-01
We present experimental total cross sections for electron scattering from furfural in the energy range from 10 to 1000 eV, as measured using a double electrostatic analyzer gas cell electron transmission experiment. These results are compared to theoretical data for furfural, as well as to experimental and theoretical values for the structurally similar molecules furan and tetrahydrofuran. The measured total cross section is in agreement with the theoretical results obtained by means of the independent-atom model with screening corrected additivity rule including interference method. In the region of higher electron energies, from 500 eV to 10 keV, the total electron scattering cross section is also estimated using a semi-empirical model based on the number of electrons and dipole polarizabilities of the molecular targets. Together with the recently measured differential and integral cross sections, and the furfural energy-loss spectra, the present total cross section data nearly complete the data set that is required for numerical simulation of low-energy electron processes in furfural, covering the range of projectile energies from a few electron volts up to 10 keV.
Surface oxidation on thin films affects ionization cross section induced by proton beam
Bertol, Ana Paula Lamberti; Vasconcellos, M.A.Z.; Hinrichs, Ruth; Limandri, Silvina; Trincavelli, Jorge
2012-01-01
Full text: In microanalysis techniques such as Particle Induced X-ray Emission (PIXE), the transformation from intensity to concentration is made by standard less software that needs exact values of fundamental parameters such as the ionization cross section, transition probabilities of the different electronic levels, and fluorescent yield. The three parameters together measure the photon generating probability of an electronic transition and can be determined experimentally under the name of production cross section. These measurements are performed on thin films, with thickness around 10 nm, but most studies do not take into account any spontaneous surface oxidation. In this work, in the attempt to obtain cross section values of Al, Si and Ti, in metallic and oxide films, the influence of surface oxidation on the metallic films was established. Simulations considering the oxidation with the software SIMNRA on the Rutherford backscattering (RBS) spectra obtained from the films provided mass thickness values used to calculate the cross section data that were compared with theoretical values (PWBA and ECPSSR), and with experimental values and empirical adjustments from other studies. The inclusion of the natural oxidation affects the values of cross section, and may be one of the causes of discrepancies between the experimental values published in literature. (author)
Barbosa, Alessandra Souza [Departamento de Física, Universidade Federal do Paraná, CP 19044, 81531-990 Curitiba, Paraná (Brazil); Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Varella, Márcio T. do N. [Instituto de Física, Universidade de São Paulo, Rua do Matão 1731, 05508-090 São Paulo, SP (Brazil); Sanchez, Sergio d’A.; Bettega, Márcio H. F., E-mail: bettega@fisica.ufpr.br [Departamento de Física, Universidade Federal do Paraná, CP 19044, 81531-990 Curitiba, Paraná (Brazil); Ameixa, João; Limão-Vieira, Paulo; Ferreira da Silva, Filipe [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Blanco, Francisco [Departamento de Física Atómica, Molecular y Nuclear, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); and others
2016-08-28
In this work, we report theoretical and experimental cross sections for elastic scattering of electrons by chlorobenzene (ClB). The theoretical integral and differential cross sections (DCSs) were obtained with the Schwinger multichannel method implemented with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR). The calculations with the SMCPP method were done in the static-exchange (SE) approximation, for energies above 12 eV, and in the static-exchange plus polarization approximation, for energies up to 12 eV. The calculations with the IAM-SCAR method covered energies up to 500 eV. The experimental differential cross sections were obtained in the high resolution electron energy loss spectrometer VG-SEELS 400, in Lisbon, for electron energies from 8.0 eV to 50 eV and angular range from 7{sup ∘} to 110{sup ∘}. From the present theoretical integral cross section (ICS) we discuss the low-energy shape-resonances present in chlorobenzene and compare our computed resonance spectra with available electron transmission spectroscopy data present in the literature. Since there is no other work in the literature reporting differential cross sections for this molecule, we compare our theoretical and experimental DCSs with experimental data available for the parent molecule benzene.
Neutron-photon multigroup cross sections for neutron energies up to 400 MeV: HILO86R
Kotegawa, Hiroshi; Nakane, Yoshihiro; Hasegawa, Akira; Tanaka, Shun-ichi
1993-02-01
A macroscopic multigroup cross section library of 66 neutron and 22 photon groups for neutron energies up to 400 MeV: HILO86R is prepared for 10 typical shielding materials; water, concrete, iron, air, graphite, polyethylene, heavy concrete, lead, aluminum and soil. The library is a revision of the DLC-119/HILO86, in which only the cross sections below 19.6 MeV have been exchanged with a group cross section processed from the JENDL-3 microscopic cross section library. In the HILO86R library, self shielding factors are used to produce effective cross sections for neutrons less than 19.6 MeV considering rather coarse energy meshes. Energy spectra and dose attenuation in water, concrete and iron have been compared among the HILO, HILO86 and HILO86R libraries for different energy neutron sources. Significant discrepancy has been observed in the energy spectra less than a couple of MeV energy in iron among the libraries, resulting large difference in the dose attenuation. The difference was attributed to the effect of self-shielding factor, namely to the difference between infinite dilution and effective cross sections. Even for 400 MeV neutron source the influence of the self-shielding factor is significant, nevertheless only the cross sections below 19.6 MeV are exchanged. (author)
Photoneutron and Photonuclear Cross Sections According to Packed cluster Model
El-Mekkawi, L.S.; El-Bakty, O.M.
1998-01-01
Photonuclear gross sections have been estimated for 232 Th, 237 Np, 239 Pu, 233 U, 234 U, 235 U, 238 U in the energy range from threshold up to 20 MeV, by perturbation balance in Packed Cluster. The Packed Cluster (gamma, f) and (gamma, n) cross sections require complete absence of any (gamma,2n) or (gamma,nf) cross sections for 233 U and 234 U as in experiment. It also explains the early (gamma,n) and gamma,nf) reactions in 235 U
Measurements of neutron cross sections of radioactive waste nuclides
Katoh, Toshio [Gifu College of Medical Technology, Seki, Gifu (Japan); Harada, Hideo; Nakamura, Shoji; Tanase, Masakazu; Hatsukawa, Yuichi
1998-01-01
Accurate nuclear reaction cross sections of radioactive fission products and transuranic elements are required for research on nuclear transmutation methods in nuclear waste management. Important fission products in the nuclear waste management are {sup 137}Cs, {sup 135}Cs, {sup 90}Sr, {sup 99}Tc and {sup 129}I because of their large fission yields and long half-lives. The present authors have measured the neutron capture cross sections and resonance integrals of {sup 137}Cs, {sup 90}Sr and {sup 99}Tc. The purpose of this study is to measure the neutron capture cross sections and resonance integrals of nuclides, {sup 129}I and {sup 135}Cs accurately. Preliminary experiments were performed by using Rikkyo University Reactor and JRR-3 reactor at Japan Atomic Energy Research Institute (JAERI). Then, it was decided to measure the cross section and resonance integral of {sup 135}Cs by using the JRR-3 Reactor because this measurement required a high flux reactor. On the other hand, those of {sup 129}I were measured at the Rikkyo Reactor because the product nuclides, {sup 130}I and {sup 130m}I, have short half-lives and this reactor is suitable for the study of short lived nuclide. In this report, the measurements of the cross section and resonance integral of {sup 135}Cs are described. To obtain reliable values of the cross section and resonance integral of {sup 135}Cs(n, {gamma}){sup 136}Cs reaction, a quadrupole mass spectrometer was used for the mass analysis of nuclide in the sample. A progress report on the cross section of {sup 134}Cs, a neighbour of {sup 135}Cs, is included in this report. A report on {sup 129}I will be presented in the Report on the Joint-Use of Rikkyo University Reactor. (author)
View-CXS neutron and photon cross-sections viewer
Subbaiah, K.V.; Sunil Sunny, C.
2004-01-01
A graphical user-friendly interface is developed in Visual Basic (VB)-6 to view the variation of neutron and photon interaction cross-sections of different isotopes as a function of energy. VB subroutines developed read the binary data files of cross-sections created in MCNP-ACE (Briesmeister, J.F., 1993. MCNP - a general purpose Monte Carlo N-Particle Transport code. Version 4A. LANL, USA), ANISN-DLC (Engle W.W. Jr., 1967, A User's Manual for ANISN, K-1693; ORNL, 1974. 100 group neutron cross section data based on ENDF/B-III. Oak Ridge National Laboratory, USA) and KENO-AMPX (Petrie, L.M., Landers, N.F., 1984 KENO-Va- An Improved Monte Carlo Criticality Program with Super Grouping. RSICC-CCC-548, USA) formats using LAHEY-77 Fortran Compiler. The information on isotopes present in each library will be displayed with the help of database files prepared using Micro-Soft ACESS. The cross-section data can be viewed in different presentation styles namely, line graphs, bar graphs, histograms etc., with different color and symbol options. The cross-section plots generated can be saved as Bit-Map file to embed in any other text files. This software enables inter comparison of cross-sections from different type of libraries for isotopes as well as mixtures. Provision is made to view the cross-sections for nuclear reactions such as (n,γ), (n,f), (n,α), etc. The software can be obtained from Radiation Safety Information and Computational Centre (RSICC), ORNL, USA with the code package identification number PSR-514. The software package needs a hard disk space of about 80 MB when installed and works in WINDOWS-95/98/2000 operating systems
Inclined Bodies of Various Cross Sections at Supersonic Speeds
Jorgensen, Leland H.
1958-01-01
To aid in assessing effects of cross-sectional shape on body aerodynamics, the forces and moments have been measured for bodies with circular, elliptic, square, and triangular cross sections at Mach numbers 1.98 and 3.88. Results for bodies with noncircular cross sections have been compared with results for bodies of revolution having the same axial distribution of cross-sectional area (and, thus, the same equivalent fineness ratio). Comparisons have been made for bodies of fineness ratios 6 and 10 at angles of attack from 0 deg to about 20 deg and for Reynolds numbers, based on body length, of 4.0 x 10(exp 6) and 6.7 x 10(exp 6). The results of this investigation show that distinct aerodynamic advantages can be obtained by using bodies with noncircular cross sections. At certain angles of bank, bodies with elliptic, square, and triangular cross sections develop considerably greater lift and lift-drag ratios than equivalent bodies of revolution. For bodies with elliptic cross sections, lift and pitching-moment coefficients can be correlated with corresponding coefficients for equivalent circular bodies. It has been found that the ratios of lift and pitching-moment coefficients for an elliptic body to those for an equivalent circular body are practically constant with change in both angle of attack and Mach number. These lift and moment ratios are given very accurately by slender-body theory. As a result of this agreement, the method of NACA Rep. 1048 for computing forces and moments for bodies of revolution has been simply extended to bodies with elliptic cross sections. For the cases considered (elliptic bodies of fineness ratios 6 and 10 having cross-sectional axis ratios of 1.5 and 2), agreement of theory with experiment is very good. As a supplement to the force and moment results, visual studies of the flow over bodies have been made by use of the vapor-screen, sublimation, and white-lead techniques. Photographs from these studies are included in the report.
EDDIX--a database of ionisation double differential cross sections.
MacGibbon, J H; Emerson, S; Liamsuwan, T; Nikjoo, H
2011-02-01
The use of Monte Carlo track structure is a choice method in biophysical modelling and calculations. To precisely model 3D and 4D tracks, the cross section for the ionisation by an incoming ion, double differential in the outgoing electron energy and angle, is required. However, the double differential cross section cannot be theoretically modelled over the full range of parameters. To address this issue, a database of all available experimental data has been constructed. Currently, the database of Experimental Double Differential Ionisation Cross sections (EDDIX) contains over 1200 digitalised experimentally measured datasets from the 1960s to present date, covering all available ion species (hydrogen to uranium) and all available target species. Double differential cross sections are also presented with the aid of an eight parameter functions fitted to the cross sections. The parameters include projectile species and charge, target nuclear charge and atomic mass, projectile atomic mass and energy, electron energy and deflection angle. It is planned to freely distribute EDDIX and make it available to the radiation research community for use in the analytical and numerical modelling of track structure.
Penning ionization cross sections of excited rare gas atoms
Ukai, Masatoshi; Hatano, Yoshihiko.
1988-01-01
Electronic energy transfer processes involving excited rare gas atoms play one of the most important roles in ionized gas phenomena. Penning ionization is one of the well known electronic energy transfer processes and has been studied extensively both experimentally and theoretically. The present paper reports the deexcitation (Penning ionization) cross sections of metastable state helium He(2 3 S) and radiative He(2 1 P) atoms in collision with atoms and molecules, which have recently been obtained by the authors' group by using a pulse radiolysis method. Investigation is made of the selected deexcitation cross sections of He(2 3 S) by atoms and molecules in the thermal collisional energy region. Results indicate that the cross sections are strongly dependent on the target molecule. The deexcitation probability of He(2 3 S) per collision increases with the excess electronic energy of He(2 3 S) above the ionization potential of the target atom or molecule. Another investigation, made on the deexcitation of He(2 1 P), suggests that the deexcitation cross section for He(2 1 P) by Ar is determined mainly by the Penning ionization cross section due to a dipole-dipole interaction. Penning ionization due to the dipole-dipole interaction is also important for deexcitation of He(2 1 P) by the target molecules examined. (N.K.)
Transport cross section for small-angle scattering
D'yakonov, M.I.; Khaetskii, A.V.
1991-01-01
Classical mechanics is valid for describing potential scattering under the conditions (1) λ much-lt α and (2) U much-gt ℎυ/α, where λ is the de Broglie wavelength, α is the characteristic size of the scatterer, U is the characteristic value of the potential energy, and υ is the velocity of the scattered particle. The second of these conditions means that the typical value of the classical scattering angle is far larger than the diffraction angle λ/α. In this paper the authors show that this second condition need not hold in a derivation of the transport cross section. In other words, provided that the condition λ much-lt α holds, it is always possible to calculate the transport cross section from the expressions of classical mechanics, even in the region U approx-lt ℎυ/α, where the scattering is diffractive,and the differential cross section is greatly different from the classical cross section. The transport cross section is found from the classical expression even in the anticlassical case U much-lt ℎυ/α, where the Born approximation can be used
Progress on FP13 Total Cross Section Measurements Capability
Ullmann, John Leonard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Couture, Aaron Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Koehler, Paul E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mocko, Michal [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mosby, Shea Morgan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wender, Stephen Arthur [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2016-09-26
An accurate knowledge of the neutron capture cross section is important for many applications. Experimental measurements are important since theoretical calculations of capture have been notoriously difficult, with the ratio of measured to calculated cross sections often a factor of 2 or more in the 10 keV to 1 MeV region. However, a direct measurement of capture cannot be made on many interesting radioactive nuclides because of their short half-life or backgrounds caused by their nuclear decay. On the other hand, neutron transmission measurements of the total cross section are feasible for a wide range of radioactive nuclides since the detectors are far from the sample, and often are less sensitive to decay radiation. The parameters extracted from a total cross section measurement, which include the average resonance spacing, the neutron strength function, and the average total radiation width, (Γ_{γ}), provide tight constraints on the calculation of the capture cross section, and when applied produce much more accurate results. These measurements can be made using the intense epithermal neutron flux at the Lujan Center on relatively small quantities of target material. It was the purpose of this project to investigate and develop the capability to make these measurements. A great deal of progress was made towards establishing this capability during 2016, including setting up the flight path and obtaining preliminary results, but more work remains to be done.
Updated ozone absorption cross section will reduce air quality compliance
E. D. Sofen
2015-12-01
et al. (2015 as 1.8 % smaller than the accepted value (Hearn, 1961 used for the preceding 50 years. Thus, ozone measurements that applied the older cross section systematically underestimate the amount of ozone in air. We correct the reported historical surface data from North America and Europe and find that this modest change in cross section has a significant impact on the number of locations that are out of compliance with air quality regulations if the air quality standards remain the same. We find 18, 23, and 20 % increases in the number of sites that are out of compliance with current US, Canadian, and European ozone air quality health standards for the year 2012. Should the new cross-section value be applied, it would impact attainment of air quality standards and compliance with relevant clean air acts, unless the air quality target values themselves were also changed proportionately. We draw attention to how a small change in gas metrology has a global impact on attainment and compliance with legal air quality standards. We suggest that further laboratory work to evaluate the new cross section is needed and suggest three possible technical and policy responses should the new cross section be adopted.
Electron-collision excitation cross section of the silver atom
Krasavin, A.Y.; Kuchenev, A.N.; Smirnov, Y.M.
1983-01-01
The cross sections for direct excitation by electron collision were measured for fifteen transitions of the silver atom. For thirteen of these transitions the optical excitation functions were recorded, varying the energy of the exciting electrons from the threshold energy to 250 eV. The operating region of the spectrum was 2000--5500 A. The excitation cross sections of the two principal lines exceeded the excitation cross sections of all the remaining lines by more than an order of magnitude. Reabsorption of the resonance lines was detected from the change in the ratio of intensities of the lines at 3280.68 and 3382.89 A, and so their intensity has been corrected relative to the intensities of the nonreabsorbed lines. All radiative transitions, with the exception of resonance transitions, participate in cascade population of the lowest resonance levels, making it possible to determine the resulting direct excitation cross sections of the 5p 2 P/sub 1/2/ and 5p 2 P/sub 3/2/ levels from the ground state of the silver atom. The part played by cascade population of the resonance levels is not large and is 2 P/sub 3/2/ level, and 10% for the 5p 2 P/sub 1/2/ level, of the excitation cross sections of the corresponding resonance transitions
(n, Xn) cross sections measurements at 96 MeV
Sagrado Garcia, Inmaculada C.
2006-01-01
Nucleon induced reactions in the 20-200 MeV energy range are intensively studied since a long time. The evaporation and the pre-equilibrium processes correspond to an important contribution of the production cross section in these reactions. Several theoretical approaches have been proposed and their predictions must be tested. The experimental results shown in this work are the only complete set of data for the (n, Xn) reactions in this energy range. Neutron double differential cross sections measurements using lead and iron targets for an incident neutron beam at 96 MeV were carried out at TSL laboratory, in Uppsala (Sweden). The measurements have been performed for the first time with an energy threshold of 2 MeV and for a wide angular range (15 deg.-98 deg.). Neutrons have been detected using two independent setups, DECOI and DEMON and CLODIA and SCANDAL, in order to cover the whole energy range (2-100 MeV). The angular distributions, the differential cross sections and the total inelastic production cross sections have been calculated using the double differential cross sections. The comparisons between the experimental data and the predictions given by two of the most popular simulation codes, GEANT3 and MCNPX, have been performed, as well as the comparison with the predictions of the microscopic simulation model DYWAN, selected for its original treatment of nucleon-nucleus reactions. (author) [fr
Electron-impact ionization cross section of rubidium
Kim, Y.; Migdalek, J.; Siegel, W.; Bieron, J.
1998-01-01
A theoretical model for electron-impact ionization cross section has been applied to Rb and the theoretical cross section (from the threshold to 1 keV in incident energy) is in good agreement with the recent experimental data obtained using Rb atoms trapped in a magneto-optical trap. The theoretical model, called the binary-encounter endash dipole (BED) model, combines a modified Mott cross section with the high-energy behavior of Born cross sections. To obtain the continuum dipole oscillator strength df/dE of the 5s electron required in the BED model, we used Dirac-Fock continuum wave functions with a core polarization potential that reproduced the known position of the Cooper minimum in the photoionization cross section. For inner-shell ionization, we used a simpler version of df/dE, which retained the hydrogenic shape. The contributions of the 4p→4d, 5s, and 5p autoionizing excitations were estimated using the plane-wave Born approximation. As a by-product, we also present the dipole oscillator strengths for the 5s→np 1/2 and 5s→np 3/2 transitions for high principal quantum numbers n near the ionization threshold obtained from the Dirac-Fock wave functions with the same core polarization potential as that used for the continuum wave functions. copyright 1998 The American Physical Society
Simulation of multistatic and backscattering cross sections for airborne radar
Biggs, Albert W.
1986-07-01
In order to determine susceptibilities of airborne radar to electronic countermeasures and electronic counter-countermeasures simulations of multistatic and backscattering cross sections were developed as digital modules in the form of algorithms. Cross section algorithms are described for prolate (cigar shape) and oblate (disk shape) spheroids. Backscattering cross section algorithms are also described for different categories of terrain. Backscattering cross section computer programs were written for terrain categorized as vegetation, sea ice, glacial ice, geological (rocks, sand, hills, etc.), oceans, man-made structures, and water bodies. PROGRAM SIGTERRA is a file for backscattering cross section modules of terrain (TERRA) such as vegetation (AGCROP), oceans (OCEAN), Arctic sea ice (SEAICE), glacial snow (GLASNO), geological structures (GEOL), man-made structures (MAMMAD), or water bodies (WATER). AGCROP describes agricultural crops, trees or forests, prairies or grassland, and shrubs or bush cover. OCEAN has the SLAR or SAR looking downwind, upwind, and crosswind at the ocean surface. SEAICE looks at winter ice and old or polar ice. GLASNO is divided into a glacial ice and snow or snowfields. MANMAD includes buildings, houses, roads, railroad tracks, airfields and hangars, telephone and power lines, barges, trucks, trains, and automobiles. WATER has lakes, rivers, canals, and swamps. PROGRAM SIGAIR is a similar file for airborne targets such as prolate and oblate spheroids.
Can cross sections be accurately known for priori?
Pigni, M.T.; Dietrich, F.S.; Herman, M.; Oblozinsky, P.
2008-01-01
Distinct maxima and minima in the neutron total cross section uncertainties were observed in our large scale covariance calculations using a spherical optical potential. In this contribution we investigate the physical origin of this oscillating structure. Specifically, we analyze the case of neutron reactions on 56 Fe, for which total cross section uncertainties are characterized by the presence of five distinct minima at 0.1, 1.1, 5, 25, and 70 MeV. To investigate their origin, we calculated total cross sections by perturbing the real volume depth V v by its expected uncertainty ±ΔV v . Inspecting the effect of this perturbation on the partial wave cross sections we found that the first minimum (at 0.1 MeV) is exclusively due to the contribution of the s-wave. On the other hand, the same analysis at 1.1 MeV showed that the minimum is the result of the interplay between s-, p-, and d-waves; namely the change in the s-wave happens to be counterbalanced by changes in the p- and d-waves. Similar considerations can be extended for the third minimum, although it can be also explained in terms of the Ramsauer effect as well as the other ones (at 25 and 70 MeV). We discuss the potential importance of these minima for practical applications as well as the implications of this work for the uncertainties in total and absorption cross sections
High resolution measurement of the 237Np(n,f) cross section from 100keV to 2MeV
Plattard, S.; Pranal, Y.; Blons, J.
1975-01-01
237 Np fission is one of the reactions utilized in the threshold detector method of neutron spectrometry for the determination of fast neutron spectra in nuclear reactors. Therefore, an accurate knowledge of the energy-dependent fission cross section is essential for a precise generation of the spectral indices of this method. A high resolution measurement of the fission cross section is presented [fr
Ma, X. [Institute of Modern Physics, Lanzhou, GS (China); Stoehlker, T.; Bosch, F.; Brinzanescu, O.; Kozhuharov, C.; Mokler, P. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Fritzsche, S. [Kassel Univ. (Gesamthochschule) (Germany); Ludziejewski, T. [Institute of Nuclear Physics, Swierk (Poland); Warczak, A. [Uniwersytet Jagiellonski, Cracow (Poland). Inst. Fizyki
2000-10-01
Balmer spectra produced in collisions between He-like uranium projectiles and gaseous targets (N{sub 2}, Ar, Kr, and Xe) were measured at the jet-target area of the ESR storage ring. The X-ray radiation were recorded in coincidence with the down charged projectiles having captured one electron from the target atom. By means of spectra simulation, all the significant Balmer transition lines were identified. Further on, the j-differential cross sections for electron capture into projectile subshells were deduced from the well resolved spectra. For the heavier targets, where NRC contributes considerably, systematic deviations between experiment and the continuum distorted wave approximation are observed. (orig.)
Proton-air and proton-proton cross sections
Ulrich Ralf
2013-06-01
Full Text Available Different attempts to measure hadronic cross sections with cosmic ray data are reviewed. The major results are compared to each other and the differences in the corresponding analyses are discussed. Besides some important differences, it is crucial to see that all analyses are based on the same fundamental relation of longitudinal air shower development to the observed fluctuation of experimental observables. Furthermore, the relation of the measured proton-air to the more fundamental proton-proton cross section is discussed. The current global picture combines hadronic proton-proton cross section data from accelerator and cosmic ray measurements and indicates a good consistency with predictions of models up to the highest energies.
Fast-neutron total and scattering cross sections of niobium
Smith, A.B.; Guenther, P.T.; Whalen, J.F.
1982-07-01
Neutron total cross sections of niobium were measured from approx. = 0.7 to 4.5 MeV at intervals of less than or equal to 50 keV with broad resolution. Differential-elastic-scattering cross sections were measured from approx. = 1.5 to 4.0 MeV at intervals of 0.1 to 0.2 MeV and at 10 to 20 scattering angles distributed between approx. = 20 and 160 degrees. Inelastically-scattered neutrons, corresponding to the excitation of levels at: 788 +- 23, 982 +- 17, 1088 +- 27, 1335 +- 35, 1504 +- 30, 1697 +- 19, 1971 +- 22, 2176 +- 28, 2456 +- (.), and 2581 +- (.) keV, were observed. An optical-statistical model, giving a good description of the observables, was deduced from the measured differential-elastic-scattering cross sections. The experimental-results were compared with the respective evaluated quantities given in ENDF/B-V.
Total Cross Section in $\\gamma\\gamma$ Collisions at LEP
Acciarri, M.; Adriani, O.; Aguilar-Benitez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M.G.; Ambrosi, G.; Anderhub, H.; Andreev, Valery P.; Angelescu, T.; Anselmo, F.; Arefev, A.; Azemoon, T.; Aziz, T.; Bagnaia, P.; Bajo, A.; Baksay, L.; Balandras, A.; Baldew, S.V.; Banerjee, S.; Banerjee, Sw.; Barczyk, A.; Barillere, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Bhattacharya, S.; Biasini, M.; Biland, A.; Blaising, J.J.; Blyth, S.C.; Bobbink, G.J.; Bohm, A.; Boldizsar, L.; Borgia, B.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J.G.; Brochu, F.; Buffini, A.; Buijs, A.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Capell, M.; Cara Romeo, G.; Carlino, G.; Cartacci, A.M.; Casaus, J.; Castellini, G.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Cesaroni, F.; Chamizo, M.; Chang, Y.H.; Chaturvedi, U.K.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Civinini, C.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; Cotorobai, F.; de la Cruz, B.; Csilling, A.; Cucciarelli, S.; Dai, T.S.; van Dalen, J.A.; D'Alessandro, R.; de Asmundis, R.; Deglon, P.; Degre, A.; Deiters, K.; della Volpe, D.; Delmeire, E.; Denes, P.; DeNotaristefani, F.; De Salvo, A.; Diemoz, M.; Dierckxsens, M.; van Dierendonck, D.; Dionisi, C.; Dittmar, M.; Dominguez, A.; Doria, A.; Dova, M.T.; Duchesneau, D.; Dufournaud, D.; Duinker, P.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Erne, F.C.; Ewers, A.; Extermann, P.; Fabre, M.; Falagan, M.A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J.H.; Filthaut, F.; Fisher, P.H.; Fisk, I.; Forconi, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Iouri; Ganguli, S.N.; Garcia-Abia, Pablo; Gataullin, M.; Gau, S.S.; Gentile, S.; Gheordanescu, N.; Giagu, S.; Gong, Z.F.; Grenier, Gerald Jean; Grimm, O.; Gruenewald, M.W.; Guida, M.; van Gulik, R.; Gupta, V.K.; Gurtu, A.; Gutay, L.J.; Haas, D.; Hasan, A.; Hatzifotiadou, D.; Hebbeker, T.; Herve, Alain; Hidas, P.; Hirschfelder, J.; Hofer, H.; Holzner, G.; Hoorani, H.; Hou, S.R.; Hu, Y.; Iashvili, I.; Jin, B.N.; Jones, Lawrence W.; de Jong, P.; Josa-Mutuberria, I.; Khan, R.A.; Kafer, D.; Kaur, M.; Kienzle-Focacci, M.N.; Kim, D.; Kim, J.K.; Kirkby, Jasper; Kiss, D.; Kittel, W.; Klimentov, A.; Konig, A.C.; Kopal, M.; Kopp, A.; Koutsenko, V.; Kraber, M.; Kraemer, R.W.; Krenz, W.; Kruger, A.; Kunin, A.; Ladron de Guevara, P.; Laktineh, I.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Lee, H.J.; Le Goff, J.M.; Leiste, R.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C.H.; Lin, W.T.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y.S.; Lubelsmeyer, K.; Luci, C.; Luckey, David; Lugnier, L.; Luminari, L.; Lustermann, W.; Ma, W.G.; Maity, M.; Malgeri, L.; Malinin, A.; Mana, C.; Mangeol, D.; Mans, J.; Marian, G.; Martin, J.P.; Marzano, F.; Mazumdar, K.; McNeil, R.R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W.J.; von der Mey, M.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G.B.; Moulik, T.; Muanza, G.S.; Muijs, A.J.M.; Musicar, B.; Musy, M.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Niessen, T.; Nisati, A.; Kluge, Hannelies; Ofierzynski, R.; Organtini, G.; Oulianov, A.; Palomares, C.; Pandoulas, D.; Paoletti, S.; Paolucci, P.; Paramatti, R.; Park, H.K.; Park, I.H.; Passaleva, G.; Patricelli, S.; Paul, Thomas Cantzon; Pauluzzi, M.; Paus, C.; Pauss, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Petersen, B.; Piccolo, D.; Pierella, F.; Pieri, M.; Piroue, P.A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Postema, H.; Pothier, J.; Prokofev, D.O.; Prokofiev, D.; Quartieri, J.; Rahal-Callot, G.; Rahaman, M.A.; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Raven, G.; Razis, P.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, Keith; Rodin, J.; Roe, B.P.; Romero, L.; Rosca, A.; Rosier-Lees, S.; Roth, Stefan; Rosenbleck, C.; Roux, B.; Rubio, J.A.; Ruggiero, G.; Rykaczewski, H.; Saremi, S.; Sarkar, S.; Salicio, J.; Sanchez, E.; Sanders, M.P.; Schafer, C.; Schegelsky, V.; Schmidt-Kaerst, S.; Schmitz, D.; Schopper, H.; Schotanus, D.J.; Schwering, G.; Sciacca, C.; Seganti, A.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Siedenburg, T.; Son, D.; Smith, B.; Spillantini, P.; Steuer, M.; Stickland, D.P.; Stone, A.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L.Z.; Sushkov, S.; Suter, H.; Swain, J.D.; Szillasi, Z.; Sztaricskai, T.; Tang, X.W.; Tauscher, L.; Taylor, L.; Tellili, B.; Teyssier, D.; Timmermans, Charles; Ting, Samuel C.C.; Ting, S.M.; Tonwar, S.C.; Toth, J.; Tully, C.; Tung, K.L.; Uchida, Y.; Ulbricht, J.; Valente, E.; Vesztergombi, G.; Vetlitsky, I.; Vicinanza, D.; Viertel, G.; Villa, S.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobev, I.; Vorobov, A.A.; Vorvolakos, A.; Wadhwa, M.; Wallraff, W.; Wang, M.; Wang, X.L.; Wang, Z.M.; Weber, A.; Weber, M.; Wienemann, P.; Wilkens, H.; Wu, S.X.; Wynhoff, S.; Xia, L.; Xu, Z.Z.; Yamamoto, J.; Yang, B.Z.; Yang, C.G.; Yang, H.J.; Yang, M.; Ye, J.B.; Yeh, S.C.; Zalite, A.; Zalite, Yu.; Zhang, Z.P.; Zhu, G.Y.; Zhu, R.Y.; Zichichi, A.; Zilizi, G.; Zimmermann, B.; Zoller, M.
2001-01-01
The reaction e+e- -> e+e- gamma* gamma* -> e+e- hadrons for quasi-real photons is studied using data from root(s) = 183 GeV up to 202 GeV. Results on the total cross sections sigma(e+e- -> e+e- hadrons) and sigma(+e- gamma* gamma* -> e+e- hadrons) are given for the two-photon centre-of-mass energies 5 GeV < Wgammagamma < 185 GeV. The total cross section of two real photons is described by a Regge parametrisation. We observe a steeper rise with the two-photon centre-of-mass energy as compared to the hadron-hadron and the photon-proton cross sections. The data are also compared to the expectations of different theoretical models.
Double-differential heavy-ion production cross sections
Miller, T. M.; Townsend, L. W.
2004-01-01
Current computational tools used for space or accelerator shielding studies transport energetic heavy ions either using a one-dimensional straight-ahead approximation or by dissociating the nuclei into protons and neutrons and then performing neutron and proton transport using Monte Carlo techniques. Although the heavy secondary particles generally travel close to the beam direction, a proper treatment of the light ions produced in these reactions requires that double-differential cross sections should be utilised. Unfortunately, no fundamental nuclear model capable of serving as an event generator to provide these cross sections for all ions and energies of interest exists currently. Herein, we present a model for producing double-differential heavy-ion production cross sections that uses heavy-ion fragmentation yields produced by the NUCFRG2 fragmentation code coupled with a model of energy degradation in nucleus-nucleus collisions and systematics of momentum distributions to provide energy and angular dependences of the heavy-ion production. (authors)
Total cross sections of beauty and charmed mesons on protons
Fridman, A.
1991-06-01
Using a simple scaling law we predict the values of the total cross sections σ(B±p), σB d,s 0 , σ(bar B d,s 0 P), σ(D d,s ± P), σ(D 0 p), σ(bar D 0 p) from known total K p cross sections. We assume that mesons with the same light valence quark, q, and differing only by their heavy valence quark content, Q, have total cross sections on protons which scale as the inverse of the nth power of the reduced mass of the meson. We predict that σ(Q bar q)p > σ(bar Qq)p
Pion photoproduction cross section at large momentum transfer
Sjoegren, Johan [Univ. of Glasgow, Scotland, United Kingdom
2015-02-27
The Real Compton Scattering experiment was performed in Hall A at the Thomas Jefferson National Accelerator Facility. It was designed to measure, for Compton scattering and π^{0}-photoproduction, the differential cross section over a range of kinematic points and the polarisation transfer to the proton at a single kinematic point. The full range of the experiment in Mandelstam variables t and s was 1.6-6.46 GeV^{2} and 4.82-10.92 GeV^{2} respectively with beam energies of 2-6 GeV. The motivation for the experiment is to test the cross section and polarisation transfer predictions of perturbative QCD versus that of predictions from Generalised Parton Distribution models. This thesis will give an overview of the pertinent theory, experimental setup in Hall A and the extracting of the π^{0}-photoproduction cross section.
Light stops emerging in WW cross section measurements?
Rolbiecki, Krzysztof [IFT-UAM/CSIC, Madrid (Spain). Inst. de Fisica Teorica; Sakurai, Kazuki [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2013-03-15
Recent ATLAS and CMS measurements show a slight excess in the WW cross section measurement. While still consistent with the Standard Model within 1-2{sigma}, the excess could be also a first hint of physics beyond the Standard Model. We argue that this effect could be attributed to the production of scalar top quarks within supersymmetric models. The stops of m{sub t{sub 1}}{proportional_to}200 GeV has the right cross section and under some assumptions can significantly contribute to the final state of two leptons and missing energy. We scan this region of parameter space to find particle masses preferred by the WW cross section measurements. Taking one sample benchmark point we show that it can be consistent with low energy observables and Higgs sector measurements and propose a method to distinguish supersymmetric signal from the Standard Model contribution.
Evaluation of fission product neutron cross sections for JENDL
1984-01-01
The recent activities on the evaluation of fission product (FP) neutron cross sections for JENDL (Japanese Evaluated Nuclear Data Library) are presented briefly. The integral test of JENDL-1 FP cross section file was performed using the CFRMF sample activation data and the STEK sample reactivity data, and the ratio of experiment to calculation was nearly constant for all the samples in the STEK measurement. Therefore, a tentative analysis was performed by applying the correction to the calculated scattering reactivity component. Better agreement with the experiment was obtained after applying this correction in most cases. The evaluation work on the JENDL-2 FP neutron cross sections is now in progress. The improvement of the data evaluation is presented in an itemized form. The JENDL-2 FP file will contain the evaluated data for 100 nuclides from Kr to Tb. The improvement and the future scope of the integral test for JENDL-2 FP data are summarized. (Asami, T.)
High Energy Measurement of the Deuteron Photodisintegration Differential Cross Section
Schulte, Elaine [Univ. of Illinois, Urbana-Champaign, IL (United States)
2002-05-01
New measurements of the high energy deuteron photodisintegration differential cross section were made at the Thomas Jefferson National Accelerator Facility in Newport News, Virginia. Two experiments were performed. Experiment E96-003 was performed in experimental Hall C. The measurements were designed to extend the highest energy differential cross section values to 5.5 GeV incident photon energy at forward angles. This builds upon previous high energy measurements in which scaling consistent with the pQCD constituent counting rules was observed at 90 degrees and 70 degrees in the center of mass. From the new measurements, a threshold for the onset of constituent counting rule scaling seems present at transverse momentum approximately 1.3 GeV/c. The second experiment, E99-008, was performed in experimental Hall A. The measurements were designed to explore the angular distribution of the differential cross section at constant energy. The measurements were made symmetric about 90 degrees
Reaction cross section calculation of some alkaline earth elements
Tel, Eyyup; Kavun, Yusuf; Sarpün, Ismail Hakki
2017-09-01
Reaction cross section knowledge is crucial to application nuclear physics such as medical imaging, radiation shielding and material evaluations. Nuclear reaction codes can be used if the experimental data are unavailable or are improbably to be produced because of the experimental trouble. In this study, there action cross sections of some target alkaline earth elements have been calculated by using pre-equilibrium and equilibrium nuclear reaction models for nucleon induced reactions. While these calculations, the Hybrid Model, the Geometry Dependent Hybrid Model, the Full Exciton Model, the Cascade Exciton Model for pre-equilibrium reactions and the Weisskopf-Ewing Model for equilibrium reactions have been used. The calculated cross sections have been discussed and compared with the experimental data taken from Experimental Nuclear Reaction Data library.
Preparation of higher-actinide burnup and cross section samples
Adair, H.L.; Kobisk, E.H.; Quinby, T.C.; Thomas, D.K.; Dailey, J.M.
1981-01-01
A joint research program involving the United States and the United Kingdom was instigated about four years ago for the purpose of studying burnup of higher actinides using in-core irradiation in the fast reactor at Dounreay, Scotland. Simultaneously, determination of cross sections of a wide variety of higher actinide isotopes was proposed. Coincidental neutron flux and energy spectral measurements were to be made using vanadium encapsulated dosimetry materials in the immediate region of the burnup and cross section samples. The higher actinide samples chosen for the burnup study were 241 Am and 244 Cm in the forms of Am 2 O 3 , Cm 2 O 3 , and Am 6 Cm(RE) 7 O 21 , where (RE) represents a mixture of lanthanide sesquioxides. It is the purpose of this paper to describe technology development and its application in the preparation of the fuel specimens and the cross section specimens that are being used in this cooperative program
Reaction cross section calculation of some alkaline earth elements
Tel Eyyup
2017-01-01
Full Text Available Reaction cross section knowledge is crucial to application nuclear physics such as medical imaging, radiation shielding and material evaluations. Nuclear reaction codes can be used if the experimental data are unavailable or are improbably to be produced because of the experimental trouble. In this study, there action cross sections of some target alkaline earth elements have been calculated by using pre-equilibrium and equilibrium nuclear reaction models for nucleon induced reactions. While these calculations, the Hybrid Model, the Geometry Dependent Hybrid Model, the Full Exciton Model, the Cascade Exciton Model for pre-equilibrium reactions and the Weisskopf-Ewing Model for equilibrium reactions have been used. The calculated cross sections have been discussed and compared with the experimental data taken from Experimental Nuclear Reaction Data library.
Charge transfer cross sections for dysprosium and cerium
Adachi, Hajime; Tamura, Koji; Okazaki, Tetsuji; Shibata, Takemasa [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
1998-06-01
Symmetric resonant charge transfer cross sections between singly ionized ions and the parent atoms were measured for dysprosium and cerium in the impact energy of 200-2000eV. The cross sections were determined from the ratio between the number of ions produced by charge transfer and those in primary ion beam. The primary ion beam was produced by a laser ion source in which their atoms were ionized by laser resonant photo-ionization. The slow ions produced by charge transfer and fast primary ions were detected with Faraday cups. The obtained cross sections were (1.82{+-}0.14) x 10{sup -14} cm{sup 2} for dysprosium and (0.88{+-}0.12) x 10{sup -14} cm{sup 2} for cerium in the above energy range. The difference of these values can mostly be explained by considering the electron configurations of these atoms and ions. (author)
Light stops emerging in WW cross section measurements?
Rolbiecki, Krzysztof
2013-03-01
Recent ATLAS and CMS measurements show a slight excess in the WW cross section measurement. While still consistent with the Standard Model within 1-2σ, the excess could be also a first hint of physics beyond the Standard Model. We argue that this effect could be attributed to the production of scalar top quarks within supersymmetric models. The stops of m t 1 ∝200 GeV has the right cross section and under some assumptions can significantly contribute to the final state of two leptons and missing energy. We scan this region of parameter space to find particle masses preferred by the WW cross section measurements. Taking one sample benchmark point we show that it can be consistent with low energy observables and Higgs sector measurements and propose a method to distinguish supersymmetric signal from the Standard Model contribution.
Inclusive cross sections in AA collisions at high energies
Braun, M.A.
1988-01-01
Inclusive cross sections in AA collisions at high energies are considered in the Glauber multiple scattering theory taking into account many-nucleon collisions. Correspondence is found between the AA amplitude and the effective action of the two-dimensional quantum field theory with exponential interaction. The tree and one-loop contributions are calculated in this formalism. The rules are derived, which relate the absorption part of the AA-collision amplitudes associated with various inclusive cross sections to the absorption parts of NN amplitudes. These rules generalize the well-known Agranowsky-Gribov-Kanchelli rules for hh and hA collisions. Formulas are written for single and double inclusive cross sections in AA collisions
Fast-neutron total and scattering cross sections of niobium
Smith, A.B.; Guenther, P.T.; Whalen, J.F.
1982-07-01
Neutron total cross sections of niobium were measured from approx. = 0.7 to 4.5 MeV at intervals of less than or equal to 50 keV with broad resolution. Differential-elastic-scattering cross sections were measured from approx. = 1.5 to 4.0 MeV at intervals of 0.1 to 0.2 MeV and at 10 to 20 scattering angles distributed between approx. = 20 and 160 degrees. Inelastically-scattered neutrons, corresponding to the excitation of levels at: 788 +- 23, 982 +- 17, 1088 +- 27, 1335 +- 35, 1504 +- 30, 1697 +- 19, 1971 +- 22, 2176 +- 28, 2456 +- (.), and 2581 +- (.) keV, were observed. An optical-statistical model, giving a good description of the observables, was deduced from the measured differential-elastic-scattering cross sections. The experimental-results were compared with the respective evaluated quantities given in ENDF/B-V
Cross-Sectional Transport Imaging in a Multijunction Solar Cell
Haegel, Nancy M.; Ke, Chi-Wen; Taha, Hesham; Guthrey, Harvey; Fetzer, C. M.; King, Richard
2015-06-14
Combining highly localized electron-beam excitation at a point with the spatial resolution capability of optical near-field imaging, we have imaged carrier transport in a cross-sectioned multijunction (GaInP/GaInAs/Ge) solar cell. We image energy transport associated with carrier diffusion throughout the full width of the middle (GaInAs) cell and luminescent coupling from point excitation in the top cell GaInP to the middle cell. Supporting cathodoluminescence and near-field photoluminescence measurements demonstrate excitation-dependent Fermi level splitting effects that influence cross-sectioned spectroscopy results as well as transport limitations on the spatial resolution of cross-sectional measurements.
Fission-neutron displacement cross sections in metals
Takamura, Saburo; Aruga, Takeo; Nakata, Kiyotomo
1985-01-01
The sensitivity damage rates for 22 metals were measured after fission-spectrum neutron irradiation at low temperature and the experimental damage rates were compared with the theoretical calculation. The relation between the theoretical displacement cross section and the atomic weight of metals can be written by two curves; one is for fcc and hcp metals, and another is for bcc metals. On the other hand, the experimental displacement cross section versus atomic weight is shown approximately by a curve for both fcc and bcc metals, and the cross section for hcp metals deviates from the curve. The defect production efficiency is 0.3-0.4 for fcc metals and 0.6-0.8 for bcc metals. (orig.)
Absolute cross-section measurements of inner-shell ionization
Schneider, Hans; Tobehn, Ingo; Ebel, Frank; Hippler, Rainer
1994-12-01
Cross section ratios for K- and L-shell ionization of thin silver and gold targets by positron and electron impact have been determined at projectile energies of 30 70 keV. The experimental results are confirmed by calculations in plane wave Born approximation (PWBA) which include an electron exchange term and account for the deceleration or acceleration of the incident projectile in the nuclear field of the target atom. We report first absolute cross sections for K- and L-shell ionization of silver and gold targets by lepton impact in the threshold region. We have measured the corresponding cross sections for electron (e-) impact with an electron gun and the same experimental set-up.
Charge transfer cross sections for dysprosium and cerium
Adachi, Hajime; Tamura, Koji; Okazaki, Tetsuji; Shibata, Takemasa
1998-06-01
Symmetric resonant charge transfer cross sections between singly ionized ions and the parent atoms were measured for dysprosium and cerium in the impact energy of 200-2000eV. The cross sections were determined from the ratio between the number of ions produced by charge transfer and those in primary ion beam. The primary ion beam was produced by a laser ion source in which their atoms were ionized by laser resonant photo-ionization. The slow ions produced by charge transfer and fast primary ions were detected with Faraday cups. The obtained cross sections were (1.82±0.14) x 10 -14 cm 2 for dysprosium and (0.88±0.12) x 10 -14 cm 2 for cerium in the above energy range. The difference of these values can mostly be explained by considering the electron configurations of these atoms and ions. (author)
Photoabsorption spectra in the perturbative regime for atoms in crossed electric and magnetic fields
Marxer, H.; Moser, I.; O'Mahony, P.F.; Mota-Furtado, F.
1994-01-01
We calculate photoabsorption spectra of atoms in crossed electric and magnetic fields using a truncated basis of Coulomb eigenfunctions. The method yields spectra in the regime where inter-n-mixing is not dominant and allows for the treatment of non-hydrogenic atoms via a simple recourse to quantum defects. We compare results for hydrogen to those obtained in second order perturbation theory where the residual degeneracy left in first order perturbation theory is completely lifted and we show that only a very small basis size is needed to achieve convergence to within the accuracy of second order perturbation theory. In the case of lithium the coupling of an incomplete hydrogen-like manifold to states with non-negligible quantum defects substantially modifies the spectra obtained in comparison to the purely hydrogenic spectra. In the inter-n-mixing regime we also compare our convoluted results directly with an experimental spectrum for hydrogen and find good agreement below the saddle point. (Author)
Asymptotic behaviour of pion-pion total cross-sections
Greynat, David [Dipartimento di Scienze Fisiche, Universita di Napoli “Federico II”,Via Cintia, 80126 Napoli (Italy); Rafael, Eduardo de [Aix-Marseille Université, CNRS,CPT, UMR 7332, 13288 Marseille (France); Université de Toulon, CNRS,CPT, UMR 7332, 83957 La Garde (France); Vulvert, Grégory [Departament de Física Teórica, IFIC,CSIC - Universitat de València, Apt. Correus 22085, E-46071 València (Spain)
2014-03-24
We derive a sum rule which shows that the Froissart-Martin bound for the asymptotic behaviour of the ππ total cross sections at high energies, if modulated by the Lukaszuk-Martin coefficient of the leading log{sup 2} s behaviour, cannot be an optimal bound in QCD. We next compute the total cross sections for π{sup +}π{sup −}, π{sup ±}π{sup 0} and π{sup 0}π{sup 0} scattering within the framework of the constituent chiral quark model (CχQM) in the limit of a large number of colours N{sub c} and discuss their asymptotic behaviours. The same ππ cross sections are also discussed within the general framework of Large-N{sub c} QCD and we show that it is possible to make an Ansatz for the isospin I=1 and I=0 spectrum which satisfy the Froissart-Martin bound with coefficients which, contrary to the Lukaszuk-Martin coefficient, are not singular in the chiral limit and have the correct Large-N{sub c} counting. We finally propose a simple phenomenological model which matches the low energy behaviours of the σ{sub π{sup ±}π{sup 0total}}(s) cross section predicted by the CχQM with the high energy behaviour predicted by the Large-N{sub c} Ansatz. The magnitude of these cross sections at very high energies is of the order of those observed for the pp and pp-bar scattering total cross sections.
Neutrino-nucleus cross sections for oscillation experiments
Katori, Teppei; Martini, Marco
2018-01-01
Neutrino oscillations physics is entering an era of high precision. In this context, accelerator-based neutrino experiments need a reduction in systematic errors to the level of a few percent. Today, one of the most important sources of systematic errors are neutrino-nucleus cross sections which, in the energy region of hundreds of MeV to a few GeV, are known to a precision not exceeding 20%. In this article we review the present experimental and theoretical knowledge of neutrino-nucleus interaction physics. After introducing neutrino-oscillation physics and accelerator-based neutrino experiments, we give an overview of general aspects of neutrino-nucleus cross sections, from both the theoretical and experimental point of view. Then, we focus on these cross sections in different reaction channels. We start with the quasi-elastic and quasi-elastic-like cross section, placing a special emphasis on the multinucleon emission channel, which has attracted a lot of attention in the last few years. We review the main aspects of the different microscopic models for this channel by discussing analogies and the differences among them. The discussion is always driven by a comparison with the experimental data. We then consider the one-pion production channel where agreement between data and theory remains highly unsatisfactory. We describe how to interpret pion data, and then analyze, in particular, the puzzle related to the difficulty of theoretical models and Monte Carlo to simultaneously describe MiniBooNE and MINERvA experimental results. Inclusive cross sections are also discussed, as well as the comparison between the {ν }μ and {ν }e cross sections, relevant for the charge-conjugation-parity violation experiments. The impact of nuclear effects on the reconstruction of neutrino energy and on the determination of the neutrino-oscillation parameters is also reviewed. Finally, we look to the future by discussing projects and efforts in relation to future detectors, beams
Cross sections for fast-neutron interaction with ytterbium isotopes
Luo, Junhua; Liu, Rong; Jiang, Li; Ge, Suhong; Liu, Zhenlai; Sun, Guihua
2013-01-01
Highlights: ► The cross sections for the (n,x) reactions on ytterbium isotopes have been measured. ► Mono-energetic neutron beams using the D + T reaction; Energies: 13.5 and 14.8 MeV. ► Neutron cross-section measurements by means of the activation technique. ► Reference reactions 93 Nb(n,2n) 92m Nb and 27 (n,α) 24 Na. ► Data for 172 Yb(n,p) 172 Tm and 176 Yb(n,d * ) 175 Tm are reported for the first time. - Abstract: Measurements of (n,2n), (n,p), and (n,d * ) (The expression (n,d * ) cross section used in this work includes a sum of (n,d), (n,np) and (n,pn) cross sections.) reaction cross-sections on ytterbium isotopes have been carried out in the range of 13.5–14.8 MeV using the activation technique. The monoenergetic neutron beams were produced via the 3 H(d,n) 3 He reaction. The neutron energies of different directions were determined using the Nb/Zr method. Samples were activated along with along with Nb and Al monitor foils to determine the incident neutron flux. Data are reported for the following reactions: 168 Yb(n,2n) 167 Yb, 170 Yb(n,2n) 169m+g Yb, 176 Yb(n,2n) 175m+g Yb, 172 Yb(n,p) 172 Tm, 173 Yb(n,p) 173 Tm, 176 Yb(n,d * ) 175 Tm, 174 Yb(n,p) 174 Tm, and 176 Yb(n,p) 176 Tm. The experimentally deduced cross-sections are compared with the existing experimental data. Furthermore, theoretical statistical model, based on the Hauser–Feshbach formalism, have been carried out using the HFTT
Smirnov, Yu.M.
1995-01-01
The trends observed in the processes of excitation with simultaneous ionization have received little study. This is particularly so for rare-earth elements having electron shells of complex structure and optical spectra very rich in lines. Among the basic factors responsible for such a situation, we should mention two: the difficulty presented by theoretical analysis of the processes discussed and the absence of factual information about the excitation cross sections with simultaneous ionization for the majority of rare-earth elements. The aim of the present work is to investigate the excitation of a singly charged gadolinium ion in the collisions of monokinetic electrons with gadolinium atoms. Up to the present time, only the excitation cross sections of a gadolinium atom have been measured, where investigation of the electron shock excitation of gadolinium atoms in their free state is associated with overcoming large experimental difficulties. About 160 crosss sections for the excitation of a singly charged gadolinium ion were measured and for a third of the cross sections; the energy dependences were recorded for the change in energy of the elecrons from the excitation threshold up to 200 eV. Included are tables of the wavelength, transistion, internal quantum number, the energy of the lowere and upper levels, and the values of cross sections for the charged gadolinium ion. Diagrams of the transistion energy states of Gd (II) and spectroscopy are presented and explained
Kalka, H.; Torjman, M.; Seeliger, D.; Lopez, R.
1989-07-01
A unique description of (n,p) and (n,2n) activation cross sections as well as emission spectra is proposed within a pure multistep approach. Calculations are presented for 8 nuclei (A=47...65) in the incident energy range from zero up to 20 MeV. (author). 42 refs, 5 figs, 1 tab
Neutron cross-sections of deuterium in the energy range 0.0001eV-15MeV
Bazazyants, N.O.; Zabrodskaya, A.S.; Larina, A.F.; Nikolaev, M.N.
1978-08-01
The paper describes the evaluation of deuterium neutron cross-sections, the spectra of neutrons from the reaction D(n,2n)P and the angular distributions of neutrons from this reaction and of neutrons elastically scattered on deuterium. The evaluation results are presented in the SOCRATOR format. The 26-group system of constants for deuterium is also presented. (author)
Elastic scattering and total cross section at very high energies
Castaldi, R.; Sanguinetti, G.
1985-01-01
The aim of this review is to summarize the recent progress in the field of elastic scattering and total cross section in this new energy domain. In Section 2 a survey of the experimental situation is outlined. The most significant data are presented, with emphasis on the interpretation, not the specific details or technicalities. This section is therefore intended to give a self-contained look at the field, especially for the nonspecialist. In Section 3, hadron scattering at high energy is described in an impact parameter picture, which provides a model-independent intuitive geometrical representation. The diffractive character of elastic scattering, seen as the shadow of inelastic absorption, is presented as a consequence of unitarity in the s-channel. Spins are neglected throughout this review, inasmuch as the asymptotic behavior in the very high-energy limit is the main concern here. In Section 4 some relevant theorems are recalled on the limiting behavior of hadron-scattering amplitudes at infinite energy. There is also a brief discussion on how asymptotically rising total cross sections imply scaling properties in the elastic differential cross sections. A quick survey of eikonal models is presented and their predictions are compared with ISR and SPS Collider data
Effects of shape differences in the level densities of three formalisms on calculated cross-sections
Fu, C.Y.; Larson, D.C.
1998-01-01
Effects of shape differences in the level densities of three formalisms on calculated cross-sections and particle emission spectra are described. Reactions for incident neutrons up to 20 MeV on 58 Ni are chosen for illustrations. Level density parameters for one of the formalisms are determined from the available neutron resonance data for one residual nuclide in the binary channels and from fitting the measured (n,n'), (n,p) and (n,α) cross-sections for the other two residual nuclides. Level density parameters for the other two formalisms are determined such that they yield the same values as the above one at two selected energies. This procedure forces the level densities from the three formalisms used for the binary pat of the calculation to be as close as possible. The remaining differences are in their energy dependences (shapes). It is shown that these shape differences alone are enough to cause the calculated cross-sections and particle emission spectra to be different by up to 60%. (author)
Update to the R33 cross section file format
Vickridge, I.C.
2003-01-01
In September 1991, in response to the workshop on cross sections for Ion Beam Analysis (IBA) held in Namur (July 1991, Nuclear Instruments and Methods B66(1992)), a simple ascii format was proposed to facilitate transfer and collation of nuclear reaction cross section data for Ion Beam Analysis (IBA) and especially for Nuclear Reaction Analysis (NRA). Although intended only as a discussion document, the ascii format - referred to as the R33 (Report 33) format - has become a de facto standard. In the decade since this first proposal there have been spectacular advances in computing power and in software usability, however the cross-platform compatibility of the ascii character set has ensured that the need for an ascii format remains. Nuclear reaction cross section data for Nuclear Reaction analysis has been collected and archived on internet web sites over the last decade. This data has largely been entered in the R33 format, although there is a series of elastic cross sections that are expressed as the ratio to the corresponding Rutherford cross sections that have been entered in a format referred to as RTR (ratio to Rutherford). During this time the R33 format has been modified and added to - firstly to take into account angular distributions, which were not catered for in the first proposal, and more recently to cater for elastic cross sections expressed as the ratio-to- Rutherford, which it is useful to have for some elastic scattering programs. It is thus timely to formally update the R33 format. There also exists the large nuclear cross section data collections of the Nuclear Data Network - of which the core centres are the OECD NEA Nuclear Data Bank, the IAEA Nuclear Data Section, the Brookhaven National Laboratory National Nuclear Data Centre and CJD IPPE Obninsk, Russia. The R33 format is now proposed to become a legal computational format for the NDN. It is thus also necessary to provide an updated formal definition of the R33 format in order to provide
PCS a code system for generating production cross section libraries
Cox, L.J.
1997-01-01
This document outlines the use of the PCS Code System. It summarizes the execution process for generating FORMAT2000 production cross section files from FORMAT2000 reaction cross section files. It also describes the process of assembling the ASCII versions of the high energy production files made from ENDL and Mark Chadwick's calculations. Descriptions of the function of each code along with its input and output and use are given. This document is under construction. Please submit entries, suggestions, questions, and corrections to (ljc at sign llnl.gov) 3 tabs
On analytical fits for electron impact ionisation cross sections
Godunov, A.L.; Ivanov, P.B.
1999-01-01
The problem of providing accurate recommended analytical fits for electron impact ionisation cross sections is discussed, and a number of approaches are considered on the sample case of neon and its ions. The previously known fits are being reassessed using complete experimental and theoretical data, with the preference for experiment, to avoid systematic shifts introduced by the present calculation methods. The feasibility of the standard BELI formula is investigated in detail, and a number of other analytical expressions is suggested, approximating single-ionization cross sections in the whole range of energies. The factors influencing the accuracy of the fits and the physical meaning of the parameters obtained are discussed. (orig.)
Heavy flavour hadro-production cross-sections
Wöhri, H K
2003-01-01
Hadro-production data on charm and beauty absolute cross-sections, collected by experiments at CERN, DESY and Fermilab, are reviewed. The measurements, corrected for the 'time evolution' of the branching ratios, are compared to calculations done with Pythia, as a function of the collision energy, using the latest parametrizations of the parton densities. We then estimate some charm and beauty production cross-sections relevant for future measurements, including nuclear effectes in the PDFs. We finish by briefly addressing the relevance, in heavy-ion collisions, of beauty production as feed-down for J/psi production.
Cross-sectional study of health effects of cryolite production
Friis, Henrik; Clausen, J; Gyntelberg, F
1989-01-01
A cross-sectional health study of 101 cryolite workers was performed, using spirometry and a questionnaire. Multiple regression analysis revealed a significant correlation between the index of smoking and a decrease in FEV1 (per cent). There was no significant correlation between work-related exp......A cross-sectional health study of 101 cryolite workers was performed, using spirometry and a questionnaire. Multiple regression analysis revealed a significant correlation between the index of smoking and a decrease in FEV1 (per cent). There was no significant correlation between work...
Controlling inclusive cross sections in parton shower + matrix element merging
Plaetzer, Simon
2012-11-01
We propose an extension of matrix element plus parton shower merging at tree level to preserve inclusive cross sections obtained from the merged and showered sample. Implementing this constraint generates approximate next-to-leading order (NLO) contributions similar to the LoopSim approach. We then show how full NLO, or in principle even higher order, corrections can be added consistently, including constraints on inclusive cross sections to account for yet missing parton shower accuracy at higher logarithmic order. We also show how NLO accuracy below the merging scale can be obtained.
The 53Cr(γ,p)52V cross section
Baciu, G.; Catana, D.; Galateanu, V.; Niculescu, R.I.V.
1979-01-01
The cross section of the photonuclear reaction 53 Cr(γ,p) 52 V between 14.4 MeV and 27 MeV was determined by the activation method. Chromium with natural isotopic abundance was irradiated in the bremsstrahlung beam of a betatron and γ rays were measured with a Ge(Li) spectrometer. Interfering reactions 52 Cr(n,p) 52 V and 54 Cr(γ,np) 52 V were evaluated. The stucture of the cross section curve is interpreted in terms of isospin splitting. (author)