Nuclear reaction cross-section

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Nucleon Transfer Reaction Studies at GANIL using Radioactive Nuclear Beams

Nucleon Transfer Reaction Studies at GANIL using Radioactive Nuclear Beams

nucleon are displayed in Fig. 1(b). In the spectrum deposited energy versus laboratory angle of the target-like particle, we can see the different regions that are populated for the different exit channels and different excited states. Note that, in these simulations, the kinematical energy-angle correlation of the target- like particle is taken into account and the angular distribution of the differential cross section dσ/dΩ is assumed to be flat for all exit channels. Also, at this stage of the simulation code development, the effect of the target thickness on the energy and angular resolution hasn’t been yet taken into account. The spectrum in Fig. 1b can be directly compared to the spectrum in Fig. 2a recorded during the experiment. The position of the two forward annular detectors was chosen with the purpose of covering the region of small laboratory angles to study the
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Nuclear structure of $^{76}\mathrm{Ni}$ from the ($p,2p$) reaction

Nuclear structure of $^{76}\mathrm{Ni}$ from the ($p,2p$) reaction

tors, (p,2p) exclusive cross sections (σ th ) together with exper- imental level energies (E exp ) and cross sections (σ exp ). The level energies and the spectroscopic factors originate from our shell model calculations while the cross sections were derived by combining DWIA cross sections and the spectroscopic fac- tors. The uncertainty in the DWIA framework and its input is about 20% as discussed in Ref. [42]. Above 4 MeV, only those excited states are shown for which the theoretical cross section exceeds 0.1 mb. Regarding the experimental data, only the first four states could be unambiguously assigned to theoretical levels. The experimental 4147 keV state and the corresponding experimental (p,2p) cross section is shown to- gether with the theoretical 4 + 3 level, however the 4147 keV state may also belong to the theoretical 5 + 1 level.
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Potential sources of uncertainties in nuclear reaction modeling

Potential sources of uncertainties in nuclear reaction modeling

When many experimental data are available, phenom- enological approaches are clearly prefered since the number of parameters on which they rely provide with a high degree of flexibility and the possibility to obtain very accurate fits of measured data. However, the price to pay is then an in depth analysis of the sensitivity of the output to the input parameters. In the case of a deformed target, beyond the OMP parameters, the adopted coupling scheme as well as the deformation parameters also play a crucial role. A typical illustration of the impact of the number of inelastic levels introduced in coupled channel (CC) methods is shown in Figure 2 . As can be observed, the total cross- sections reaches rather similar values, at least compatible with experimental data within error bars, for various choices of the number of coupled levels while the compound nucleus formation cross-section remains much more sensitive to the choice of the coupling scheme. With such differences, the other channels predictions, in particular the fission cross-section, will be clearly influenced by the number of coupled levels considered, meaning that uncertainties in the fission channel do not only depend on the sole uncertainties on fission model parameters, as it might be thought at first glance.
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Cross section measurements of deuteron induced nuclear reactions on natural titanium up to 34 MeV

Cross section measurements of deuteron induced nuclear reactions on natural titanium up to 34 MeV

Capote, R., IAEA project officer, Tarkanyi,F.T, - Chairman Reaction Data (Hungary), Nichols, A.L, - Chairman Decay Data (UK), Be, M.-M., (France), Carlson, B.V., (Brazil), Hussain, M., (Pakistan), Ignatyuk, A.V., (Russian Federation), Kim, G., (Korea), Kondev, F.G, (USA), Lebeda, O.,(Czech Republic), Luca, A., (Romania), Nagai, T., (Japan), Naik, H., (India), Nortier, M., (USA), and Spahn, I., (Germany). Duration : 2012-2016. CRP on Nuclear Data for Charged-particle Monitor Reactions and Medical Isotope Production. CRP code : F4.10.29.

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

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

b SUBATECH, EMN-IN2P3 /CNRS-Universit´e de Nantes, B.P. 20 722, 44 307 Nantes cedex 3, France Abstract A systematics of over 300 complete and incomplete fusion cross section data points covering energies beyond the barrier for fusion is presented. Owing to a usual reduction of the fusion cross sections by the total reaction cross sections and an original scaling of energy, a fusion excitation function common to all the data points is established. A universal description of the fusion exci- tation function relying on basic nuclear concepts is proposed and its dependence on the reaction cross section used for the cross section normalization is discussed. The pioneering empirical model proposed by Bass in 1974 to describe the complete fusion cross sections is rather successful for the incomplete fusion too and provides cross section predictions in satisfactory agreement with the observed universality of the fusion excitation function. The sophisticated microscopic transport DYWAN model not only reproduces the data but also predicts that fusion reaction mechanism disappears due to weakened nuclear stopping power around the Fermi energy.
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Effect of differential cross section in Breit-Wheeler pair beaming

Effect of differential cross section in Breit-Wheeler pair beaming

In summary, to investigate the BW differential cross section effect on pair beaming, three cases are considered in terms of photon beam energies: 4-4 MeV, 4-1 MeV, 4- 7 MeV, all cases with θ p = 40 ◦ . In the case 4-4 MeV, the influences of the differential cross section are important: on pair angular distribution as well as on the energy distribution. The pairs are emitted mainly in the photon beam directions. Then, less pairs are emitted in the bisector between the photon beam directions compared to the case of the isotropic differential cross section. The pair energy distribution achieved a maximum at the mean energy of the two photon beams. Concerning the two last cases: 4-1 MeV; 4-7 MeV, the pair beam is emitted mainly along the CM frame velocity direction. Because of the photon beams energy difference, less pairs are emitted on the bisector between the two photon beams. However, for of 4-1 MeV photon beams collision, the effect of BW differential cross section on the angular pair distribution and energy distributions are weak. In the case 4-7 MeV photon beams, the effect becomes important and the pair distribution is beamed in the direction of the most energetic photon beam. The energy distribution is shifted to higher energies and achieves a maximum for the mean energy of the two photon beams.
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Compton Scattering Cross Section on the Proton at High Momentum Transfer

Compton Scattering Cross Section on the Proton at High Momentum Transfer

The second correction is due to quasi-real photons from the H(e, pγ)e ′ reaction and is taken into account in the calculation of the incident photon flux. The reaction is simulated with our Monte Carlo, using the spectrum of quasi-real photons calculated according to the method of Ref. [17]. Although the scattered electron is not detected, the kinematic cuts on the HRS and calorimeter, partic- ularly the δx and δy cuts, place stringent constraints on the virtuality of the photon. We find that the quasi-real photons have a mean Q 2 = 0.14 × 10 −3 GeV 2 and con-

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Measurement of the t-channel single top quark production cross section

Measurement of the t-channel single top quark production cross section

missing transverse energy (6E T ), a b quark jet from the decay of the top quark (t→W b→ℓνb), a light quark jet produced in association with the top quark, and a spectator b quark jet from gluon splitting in the initial state. We allow for one of these jets not to be identified as well as for the presence of an additional jet from gluon radiation. The backgrounds are W bosons produced in association with jets, t¯ t pairs, and multijet production, where a jet is misreconstructed as an electron or a heavy-flavor quark decays to a muon that satisfies isolation criteria. Z+jets and diboson processes form minor additional background components. We treat s- channel single top quark production as a background during the multivariate training but measure its cross section simultaneously with the t-channel measurement as explained below.
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Quantum scattering by a disordered target  - The mean cross section

Quantum scattering by a disordered target - The mean cross section

expression in (5.5), the sum being truncated at l = 150 (dashed line), for a value of the phase shift close to π/2 (ǫ = 10 −4 ). The full line gives the values of the normalized cross section for diffusion by a hard sphere of radius R. Each figure shows that the expression in (5.5) reproduces well the mean cross section except in the uninteresting range of values of the density in which the approximation of single scattering is valid. This discrepancy reflects the fact that the contributions of more and more partial waves have to be taken into account in the sum as the radius increases, and so as the density decreases. One can therefore conclude that the uniform decrease is caused by multiple scattering.
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Approximation of the scattering cross section for aggregated spherical particles

Approximation of the scattering cross section for aggregated spherical particles

is not small, the approximation of anomalous diffraction [4] can be applied. In the Rayleigh-Debye-Gans domain, there is interference of electromagnetic waves which are independently scattered by all small volume elements. In the anomalous di_raction domain, there is straight transmission and subsequent diffraction. In this case, the scattered intensity is concentrated near the original direction of propagation and the scattering cross section obeys the relation [4]:

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Radar Cross Section Measurement within Reverberation Chamber: Stirrer position issues

Radar Cross Section Measurement within Reverberation Chamber: Stirrer position issues

3 INSA Rennes, CNRS, IETR-UMR 6164, F-35000 Rennes. * ariston.defreitastavaresdosreis@u-pem.fr Abstract—This paper presents the evaluation of the Radar Cross Section (RCS) of a metallic object by measurements accomplished within the diffuse-field environment produced by a Reverberation Chamber (RC). The method is based on the extraction of the ballistic wave between the antenna and the target that is mixed with the backscattering response of the RC. A good agreement is obtained when compared with classical RCS measurement inside an anechoic chamber. This communication also highlights the potential stirrer positioning issues and their impact on the retrieved RCS accuracy.
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Idiosyncratic Consumption Risk and the Cross-Section of Asset Returns

Idiosyncratic Consumption Risk and the Cross-Section of Asset Returns

Table VI further investigates the robustness of the results obtained in Table V, Panel D, using data on total consumption for asset holders only. We only report these results using one of the datasets to limit the number of tables. It must again be emphasized that the results for the three other datasets are possibly equally interesting from the perspective of pricing the cross-section of assets. We choose to focus on this dataset because the estimated sign of the consumption dispersion factor in Table V, Panel D, is also of interest for the related literature on the equity premium puzzle. Table VI clearly indicates the robustness of the results. Panel A presents the Þrst stage GMM estimates obtained by minimizing the HJ distance measure (13). We obtain positive estimates for the variance factors in all pricing kernels where we use factors based on cohort construction. It must be noted that the point estimates are not as signiÞcant as the ones in Table V, but this is to be expected because the Þrst stage GMM estimation is less efficient. The advantage of minimizing the HJ distance is that we can make comparisons of the HJ-distances obtained using the different kernels, because the same weighting matrix is used for different kernels. The performance of the consumption-based pricing factors is clearly impressive. The HJ-distance for the CAPM is 2.41 and serves as a benchmark. The HJ distances obtained when using factors constructed from individual consumption data in rows 1 and 7 are 2.33 in both cases. This is a lower HJ distance than for the CAPM, even though the variance factor is estimated insigniÞcantly. Most interestingly, the HJ distances are much lower when using factors based on cohorts. This is especially the case for the cohorts based on age in rows 2 and 3. When using a pricing kernel with two consumption-based factors and the market factor in rows 5, 6, 11 and 12, the HJ statistic drops even further. 21 Panel B of Table VI provides two-step GMM
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Front blocking and propagation in cylinders with varying cross section

Front blocking and propagation in cylinders with varying cross section

5 Blocking by a narrow passage In this section we prove Theorem 1.8. There are earlier results on the existence of non constant stable steady states for bistable reaction-diffusion equations with Neumann boundary con- ditions when there is a narrow passage in a number of cases. Matano [29] first showed the existence of non-constant stable solutions in the case of a bounded domain having the shape of an hourglass. The first author of the present paper together with Hamel and Matano [7] established an analogous result for an exterior domain having a narrow passage to a confined region. The paper [7] exhibits a non constant stable steady state in an exterior do- main with narrow passage where the area in which the solution is close to 0 is bounded whereas the area where the solution is close to 1 is unbounded.
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The Total Cross Section at the LHC: Models and Experimental Consequences

The Total Cross Section at the LHC: Models and Experimental Consequences

A hadronic slope B almost constant with t for |t| < 0.25 GeV 2 and a small ρ parameter are standard assumptions for the planned mea- surement of the total cross section [19]. If the two-pomeron model is correct, then these as- sumptions will be wrong, and we can evaluate the systematic uncertainty that they will gen- erate. So, we have used our unitarised two- pomeron model [20] to simulate data, using bins and errors similar to those of the UA4/2 exper- iment [21], and including the Coulomb-nucleon interference [22]. We then performed the stan- dard analysis on these simulated data, and ex- tracted a measurement of the total cross sec- tion, which we could compare to the input value from our model. The result of this analysis is that the extracted value of the total cross section will systematically overshoot the model value by about 10 mb in a luminosity-dependent method, and about 15 mb in a luminosity-independent one. Hence, an additional study of the t depen- dence of the slope and of the ρ parameter will be needed before one reaches the 1 % precision level.
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Cross-regulation of hepatic glucose metabolism ChREBP and Nuclear Receptors

Cross-regulation of hepatic glucose metabolism ChREBP and Nuclear Receptors

Lastly, ChREBP is exported from the nucleus by a mechanism requiring CRM1 (Chromosome maintenance region 1), a protein that shares sequence similarities with the karyopherin β family of proteins involved in nuclear import pathway, was shown to form a complex with the leucine-rich nuclear export signal (NES) and the ability to bind the 14-3-3 protein [54]. When the NES (NES1, located at residues 5-15 in the rat isoform) (Figure 1) is mutated [55], the binding of ChREBP to 14-3-3 and CRM1 is dramatically decreased [55]. Deletions or mutations of the key ChREBP domains, MCRII (MCR: Mondo Conserved Region) (containing the NES1) [55] [56] or MCRIII (containing the 14-3-3 binding site) [56, 57] (Figure 1) lead to an increase in ChREBP nuclear localization and both mutants keep DNA binding activity [55]. Oddly, these ChREBP mutants display a significant loss in transactivative activity under both low and high glucose conditions, suggesting that ChREBP nuclear localization is not sufficient to mediate its transcriptional effects. In fact, another study casts doubt on the importance of ChREBP nuclear translocation. Davies et al. [57] reported that the majority of ChREBP protein is localized in the cytosol under both low and high glucose conditions in 832/13 INS-1 cells. Inhibition of the CRM1-induced nuclear export using leptomycin B treatment trapped ChREBP protein in both glucose conditions, suggesting a continuous shuttle of the protein between cytosol and nucleus [57] rather than an active translocation. Nevertheless, in this study the rate of nuclear entry of ChREBP was greater under high glucose concentrations.
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Route to chaos on a dragonfly wing cross section in gliding flight

Route to chaos on a dragonfly wing cross section in gliding flight

2 FIG. 1. Flow configuration and geometry, detailed in [13]. of a 2D dragonfly wing exhibiting two corrugations with a rear arc (Fig. 1). First, the numerical setup is shown in Section II. Then, results on the various aerodynamic regimes are detailed in Section III, highlighting a sud- den transition to chaos when varying the angle of attack, without the classical period-doubling or quasi-periodic states. From the authors knowledge, such an alternative and uncommon route to chaos has been reported only on mathematical non-linear systems by Chowdhury and Roychowdhury [17]. Interestingly, it is also shown that maximum lift-to-drag ratio is obtained just before the transition to chaos, whereas maximum lift is generated before leaving the chaotic state towards the non-linear regime: optimal aerodynamic performances are therefore in close connections with the transition to chaos. Finally, the vortex dynamics and flow fields are analyzed for the several regimes.
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CAPM, Components of Beta and the Cross Section of Expected Returns

CAPM, Components of Beta and the Cross Section of Expected Returns

parametric and instrument-based approaches such as those in Harvey (1989), Shanken (1990), Ferson and Harvey (1991, 1993, 1999), Cochrane (1996), Jagannathan and Wang (1996), Ang and Chen (2007) and Rangel and Engle (2009). We show that our three component beta model can account for most of the cross-sectional variation in expected returns. Specifically, we analyze the performance of our three component beta model relative to the benchmark three factor model of Fama and French (1993, 1996) with constant factor loadings in accounting for the cross-sectional variation in expected monthly returns on the 25 size and book-to-market cross sorted portfolios for the period January 1970 to December 2010. To do this, for each month, we first estimate the short and medium-term beta components using daily data over the previous one and five year periods, respectively, and the long-run beta component using monthly data over the previous ten year period. We then calculate the average pricing error as the average of the resid- uals from the estimation of the cross-sectional regression in each month as in Fama and MacBeth (1973). Differently from our three component beta model, the factor loadings on the three Fama-French factors are estimated only once based on the whole sample period. In this framework, our three component beta model outperforms the Fama-French three factor model. Specifically, it does not only achieve lower overall pricing errors as measured by sum of squared pricing errors (SSPE) but also for each size and book-to-market quintile. Furthermore, it only fails to account for the expected return on the small-growth portfolio, which is known to be the most difficult portfolio to correctly price, compared to three mispriced assets under the Fama-French three factor model.
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Cross section generation strategy for high conversion light water reactors

Cross section generation strategy for high conversion light water reactors

A two-dimensional cross section generation methodology using the Monte Carlo code Serpent, similar to the traditional deterministic homogenization methodology, was used to [r]

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Hedge Fund Returns and Factor Models : A Cross-Section Approach

Hedge Fund Returns and Factor Models : A Cross-Section Approach

idiosyncratic component matrix. λ ′ i F t represents the common component of X it . The idiosyncratic components are supposed to have zero mean. We place our analysis in an approximate factor model framework in the sense of Bai and Ng (2002) which is more realistic in hedge fund world, since it allows for weak time and cross-section dependence and heteroscedasticity in the idiosyncratic components. The factors, their loadings, as well as the idiosyncratic errors are not observable and have to be estimated. Although it seems appealing to assume one factor, there is growing evidence against the adequacy of a single factor model in explaining hedge fund returns. For example, Fung and Hsieh (1997a) and Fung and Hsieh (1997b) show that hedge fund risk exposures are multidimensional and highly dynamic. Thus, instead of restricting the analysis by fixing r = 1, we propose a procedure to determine the appropriate number of factors 6
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Effect of antimony on the eutectic reaction of heavy section spheroidal graphite castings

Effect of antimony on the eutectic reaction of heavy section spheroidal graphite castings

Effect of antimony on the eutectic reaction of heavy section spheroidal graphite castings P. Larran ˜aga 1 , I. Asenjo 1 , J. Sertucha 1 , R. Sua´rez 1 , I. Ferrer 2 and J. Lacaze * 3 There is a strong demand for heavy section castings made of spheroidal graphite with a fully ferritic matrix, e.g. for manufacturing hubs for windmills. Such castings with slow solidification process are prone to graphite degeneration that leads to a dramatic decrease of the mechanical properties of the cast parts. Chunky graphite is certainly the most difficult case of graphite degeneracy, though it has long been known that the limited and controlled addition of antimony may help eliminate it. The drawback of this remedy is that too large Sb additions lead to other forms of degenerate graphite, and also that antimony is a pearlite promoter. As part of an investigation aimed at mastering low level additions to cast iron melts before casting, solidification of large blocks with or without Sb added was followed by thermal analysis. Comparison of the cooling curves and of the microstructures of these different castings gives suggestions to understand the controlling nucleation and growth mechanisms for chunky graphite cells.
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