Parametrization of cross sections for neutron interaction with 1^{1}H, 2^{2}H and 12^{12}C nuclei at energies between 20 and 90 MeV

The experimental data for neutron interaction with $^{1}$H, $^{2}$H and $^{12}$C nuclei are parametrized in energy range 20 to 90 MeV. The energy dependence of the total and reaction cross section is represented in the form of a series of orthogonal polynomials. The logarithm of differential cross section for the angular distribution is expressed as a linear combination of Legendre polynomials with the energy dependence of their coefficients described by a series of orthogonal polynomials

On the distribution of the fluctuating reaction cross section

Exact formula for the statistical distribution function of the fluctuating cross section is presented. Comparison with the results obtained from the approximate formula shows that such a formula can be used for calculation of the cumulative distribution function in the range of its values from 0.01 to 0.99

Study of the mechanism of the five-nucleon transfer reaction 12^{12}C(13^{13}C, 8^{8}Be)17^{17}O

Excitation functions (E$_{cm}$ = 13.4 - 16.8 MeV) and angular distributions (E$_{cm}$ = 13.8 and 16.38 MeV) of $^{12}$C($^{13}$C, $^{8}$Be)$^{17}$O reaction have been measured and analysed by means of statistical and direct reaction mechanism models. The direct reaction analysis includes one and two step processes. For this purpose measurements and analyses were also performed for the reactions $^{12}$C($^{13}$C, $^{9}$Be)$^{16}$O (at E$_{cm}$ = 13.8 MeV) and $^{16}$O($^{9}$Be, $^{8}$Be)$^{17}$O (at E$_{cm}$ = 10.3 and 12.8 MeV). The results were used to estimate the magnitude of the direct two-step (n-$^{4}$He) and ($^{4}$He-n) transfers in the $^{12}$C($^{13}$C, $^{8}$Be)$^{17}$O reaction. These two-step transfers as well as the compound nucleus mechanism, account only for approximately 10% of the experimental cross sections. Thus a dominance of the one-step five-nucleon transfer is concluded. Estimates of the direct $^{5}$He-cluster transfer describe the data qualitatively

Thermal diffusivity, effusivity and conductivity of CdMnTe mixed crystals

Cd1-xMnxTe mixed crystals belong to a class of materials called ‘‘semimagnetic semiconductor’’ or diluted magnetic semiconductor (DMS) with addition of magnetic ions like Mn2+ implemented into crystal structure. The crystals under investigation were grown from the melt by the high pressure high temperature modified Bridgman method in the range of composition 0 < x < 0.7. Thermal properties of these compounds have been investigated by means of photopyroelectric (PPE) calorimetry in both, back and front detection configuration. The values of the thermal diffusivity and effusivity were derived from experimental data. Thermal conductivity of the specimens was calculated from the simple theoretical dependencies between thermal parameters. The influence of Mn concentration on thermal properties of Cd1-xMnxTe crystals have been presented and discussed

Low-Energy \Lambda-\p Scattering Parameters from the pp→pK+Λpp \to pK^+\Lambda Reaction

Constraints on the spin-averaged $\Lambda p$ scattering length and effective range have been obtained from measurements of the $pp\to pK^+\Lambda$ reaction close to the production threshold by comparing model phase-space Dalitz plot occupations with experimental ones. The data fix well the position of the virtual bound state in the $\Lambda p$ system. Combining this with information from elastic $\Lambda p$ scattering measurements at slightly higher energies, together with the fact that the hyperdeuteron is not bound, leads to a new determination of the low energy $\Lambda p$ scattering parameters.Comment: 18 pages, 7 figure

Statistical analysis of excitation functions for elastic and inelastic scattering of α\alpha-particles on Mg and Si nuclei

The excitation functions for inelastic $\alpha$-scattering leading to the low lying excited states in $^{24}$Mg and $^{28}$Si were measured at $\Theta_{LAB}$ = 170°, 175° and 179° in the LAB energy range 22.75–28.40 MeV. Statistical analysis of these excitation functions and those previously measured for elastic scattering was performed. The direct interaction contribution $\mathit{y}_{D}$ to the reaction studied was obtained from probability distributions of cross sections and from correlation coefficients. Cross correlation coefficients between different reaction channels were calculated

Effects of the Tucson-Melbourne three-nucleon force in the proton-deuteron breakup process at Ep = 65 MeV

We present the calculated cross sections and vector analyzing powers using the Bonn B nucleon-nucleon potential and the Tucson-Melbourne three-nucleon force (3NF) for six collinearity and quasi-free scattering breakup configurations. These calculations are compared to the results of the recent kinematically complete pd experiments at Ep = 65 MeV. The Tucson-Melbourne 3NF, adjusted together with the Bonn B potential to reproduce the triton binding energy, leads to small effects both in cross sections and analyzing powers in all six studied configurations

Monitoring of the accelerator beam distributions for internal target facilities

We describe a direct method for monitoring the geometrical dimensions of a synchrotron beam at the target position for internal target installations. The method allows for the observation of the proton beam size as well as the position of the beam relative to the target. As a first demonstration of the technique, we present results obtained by means of the COSY-11 detection system installed at the cooler synchrotron COSY. The influence of the stochastic cooling on the COSY proton beam dimensions is also investigated.Comment: 7 pages, 8 figures, Submitted to Nucl. Inst. & Meth.

Near-Threshold eta Meson Production in Proton-Proton Collisions

The production of eta mesons has been measured in the proton-proton interaction close to the reaction threshold using the COSY-11 internal facility at the cooler synchrotron COSY. Total cross sections were determined for eight different excess energies in the range from 0.5 MeV to 5.4 MeV. The energy dependence of the total cross section is well described by the available phase-space volume weighted by FSI factors for the proton-proton and proton-eta pairs.Comment: 9 pages, 1 table, 5 figure

Polarimetry of 16Ngs produced in mu --capture on 16O nuclei

A polarimetry technique based on stack targets and /3-'/-coincidences has been applied to the 16N nuclei produced in the ground state capture of negative muons on lb0 nuclei. The performance of the polarimeter and the first measurements of /3-asymmetry due to the longitudinal nuclear polarization are discussed