[en] Preliminary results are presented for the accurate absolute measurement of neutron flux (neutrons/sec) by exploiting the properties of the α particles and γ rays produced in the ¹⁰B(n,α)⁷Li reaction. The measurement involves the use of thin and totally absorbing targets containing ¹⁰B as well as standard α sources and employs both singles and coincidence counting techniques. Detector efficiencies are determined by two independent methods. Comparisons with a method based on neutron calorimetry will be discussed. These measurements form an important part of an improved measurement of the neutron decay rate

[en] ¹⁰B offers a unique opportunity to test theoretical descriptions of the (e,e'p) reaction. The radial shape of the 1p_3/2 wave function can be determined from single-arm electron scattering. Since the ground state has J^πT = 3⁺0, electro-excitation of the 0⁺1 1.74 MeV state proceeds via a pure M3 multipole. In a p-shell model only the 1p_3/2→1p_3/2 single particle matrix element enters. Alternatively, one can deduce this wave function from the more complicated coincidence (e,e'p) reaction for ¹⁰B leading to the 3/2^- ground state of ⁹Be. Final state interactions not only distort the exiting nucleon wave function but also introduce additional electromagnetic multipole transitions to intermediate nuclear states and thereby confuse the extraction of the 1p_3/2 wave function from experiment. The authors use the first-order KMT optical potential and include a truncated basis composed of a small number of low-lying states to examine their effects. Sensitivity to the choice of the nucleon-nucleon T-matrix used in constructing the optical potentials as well as shell model structure information will be examined

[en] An absolute method to determine the neutron flux by avoiding the knowledge of an intermediate cross-section is presented. With this aim in view, a B¹⁰ target was used with a thickness calculated so that the neutron escape probability be less than 10^-5. Using a Ge(Li) spectrometer, the neutron capture in the boron nucleus was detected through the gamma rays of ⁷Li. Irradiating in the same neutron flux a gold foil of the same area as the boron target, the spectrometer efficiency was determined. The absolute activity of this foil was obtained with a 4πβ-γ counter. It results that, by this method, thermal neutron fluxes can be determined with an error less than 0.5%. (author)

[en] A complete set of polarization-transfer coefficients have now been measured for the ¹⁰B(p,p ^prime)'B reaction to the 0⁺ T=1 open-quotes stretchedclose quotes state at 1.74 MeV. These measurements have been performed at IUCF with the K600 high resolution spectrometer and its focal plane polarimeter. Previously, two linear combinations of the four in-plane polarization-transfer coefficients (Dip) had been measured with a spin precession angle of 235 close-quote through the spectrometer. By repositioning and rotating the focal plane detectors, we obtained a second set of measurements with a spin precession angle of 300 degrees. This permits the decomposition of the in-plane observables into the standard D _ij''s, and, along with previous normal-component spin transfer data, provides a complete set. Results will be compared with DWBA calculations for both free nucleon-nucleon and medium-modified interactions

[en] Angular distributions for the ¹⁰B(n,p)¹⁰Be gs reaction have been measured over the momentum transfer range of 0.3 to 2.0 fm and bombarding energies ranging from 50 to 250 MeV. Distorted Wave calculations using the Franey-Love interaction show that the angular distributions over incident energies 90 to 200 MeV are fit to within 10%. However, at 250 MeV we find the calculated cross section is too large by 20%. Since the cross section is dominated by the direct isovector tensor amplitude, the comparison is a good test of the energy dependence of the tensor art of the interaction

No abstract available

[en] In present study, we investigate the LPs or ERs cross sections in the decay of "2"6","2"7","2"8","2"9Al*, formed in heavy ion reactions "1"6O+"1"0","1"1B and "1"8O+"1"0","1"1B with deformations (and orientations) of the interacting nuclei included upto quadruple deformations

[en] This paper supports the thesis that significant improvement of PET output response to clinical questions can be achieved by innovation in radionuclide production. Moreover, that development can be performed with the resources available at a clinical centre. Carbon-10 production parameters studies are used as example. A technical methodology for measurement of excitation function of nuclear reactions yielding short-lived radionuclides, performed to measure cross section values of the ¹⁰B(p,n)¹⁰C reaction in a PET-devoted cyclotron, is presented

[en] Partial and total cross sections for the photodisintegration of the ¹⁰B nucleus are calculated within the framework of the shell model with intermediate coupling. The probability distribution is evaluated for the decay of dipole excitations to negative-parity levels of the ⁹Be--⁹B nuclei. The results of the calculation are compared with experimental data on the ¹⁰B(γ,n)- and ⁹Be( p,γ₀) ¹⁰B reactions

[en] Measurements have been made of the ratio of the ¹⁰B(n,α) to ⁶Li(n,t) cross sections from approx. 1 to 45 eV with statistical uncertainties and systematic errors of less than 1%. Improved experimental data were obtained in this investigation compared with a previous measurement. The measurements are consistent with results obtained from ENDF/B-V cross sections. (author)