Neutron single-particle structure of <Superscript>48</Superscript>Ca, <Superscript>50</Superscript>Ti, <Superscript>52</Superscript>Cr, <Superscript>54</Superscript>Fe,and <Superscript>56</Superscript>Ni nuclei

The change in the neutron single-particle structure of (1f?2p)-shell magic nuclei near the Fermi energy with an increase in the number of protons in the 1f _7/2 subshell from 0 for ⁴⁸Ca to 8 for ⁵⁶Ni has been investigated. Good agreement of the experimental and estimated values of the single-particle energies E _nlj of the bound states of neutrons in these nuclei with the results of calculations within the dispersive optical model is obtained.     

Elastic and inelastic scattering of 800-MeV protons on <Superscript>16</Superscript>O and <Superscript>20</Superscript>Ne nuclei

Differential cross sections and polarization observables for the elastic and inelastic scattering of 800-MeV protons on ¹⁶O and ²⁰Ne nuclei are calculated on the basis of the theory of multiple diffractive scattering and the α-cluster model involving dispersion. The single-particle nucleon-density distributions obtained within the α-cluster model involving dispersion are used in the calculations. The differential cross sections and polarization calculated for elastic and inelastic p¹⁶O and p²⁰Ne scattering are compatible with available experimental data. The spin-rotation functions calculated for elastic p¹⁶O and p²⁰Ne scattering within the independent-nucleon model differ qualitatively from their counterparts calculated within the α-cluster model involving dispersion.     

Perturbative role in the inelastic electron scattering from <Superscript>29</Superscript>Si

Inelastic electron scattering form factors away from the closed sd -shell are investigated. This investigation covers the low-lying states in ²⁹Si , which is considered according to the many-particle configuration mixing shell model as the ¹⁶O core, plus thirteen nucleons distributed over the entire sd -shell orbits. The investigation concentrates on the perturbative role of the core, which is called core polarization effects, on the inelastic electron scattering form factors. Core polarization effects are taken into consideration through the excitation of nucleons from 1s and 1p core orbits, and also from the 2s -1d valence orbits into higher shells, with 2ℏω excitations. Core polarization matrix elements are calculated with the M3Y effective interaction. For the sd -shell model space, a new Hamiltonian, based on a renormalized G -matrix, USDB, is used. All calculations are performed without adjusting any parameters.     

Coupled-channel analysis for 20.4 MeV energy of p-<Superscript>64</Superscript>Zn inelastic scattering

In this study, a coupled-channel (CC) analysis of the elastic and the inelastic scattering of 20.4 MeV polarized protons from a ⁶⁴Zn target leading to the deformed 2⁺, 3−, 2₂⁺2_2^+ states was performed. The CC potential parameters and the deformation parameters of the excited states corresponding to the best fit to the experimental differential cross-sections and the analysing powers data were determined. For 2₂⁺2_2^+ excited state, a mixed type was used and a good fit to the data was provided. The CC calculation results were compared to the pure distorted wave Born approximation (DWBA) calculation results which were calculated using the new parameters. All calculations were conducted using the computer code ECIS06.     

Nuclear level densities in <Superscript>47</Superscript>V, <Superscript>48</Superscript>V, <Superscript>49</Superscript>V, <Superscript>53</Superscript>Mn,and <Superscript>54</Superscript>Mn from neutron evaporation spectra

The spectra of neutrons from the (p, n) reactions on ⁴⁷Ti, ⁴⁸Ti, ⁴⁹Ti, ⁵³Cr, and ⁵⁴Cr nuclei were measured in the proton-energy range 7–11 MeV. The measurements were performed with the aid of a fast-neutron spectrometer by the time-of-flight method over the base of the EGP-15 tandem accelerator of the Institute for Physics and Power Engineering (IPPE, Obninsk). Owing to a high resolution and a high stability of the time-of-flight spectrometer used, low-lying discrete levels could be identified reliably along with a continuum section of neutron spectra. An analysis of measured data was performed within the statistical equilibrium and preequilibrium models of nuclear reactions. The relevant calculations were performed by using the exact formalism of Hauser-Feshbach statistical theory supplemented with the generalized model of a superfluid nucleus, the back-shifted Fermi gas model, and the Gilbert-Cameron composite formula for the nuclear level density. The nuclear level densities for ⁴⁷V, ⁴⁸V, ⁴⁹V, ⁵³Mn, and ⁵⁴Mn were determined along with their energy dependences and model parameters. The results are discussed together with available experimental data and recommendations of model systematics.     

Multichannel neutron scattering on <Superscript>11</Superscript>Be nucleus

The effect of the Pauli exclusion principle on the relative motion of colliding light neutron-rich nuclei is investigated within a microscopic method for the examples of the ¹¹Be + n and ¹⁰Be + ² n reactions. The effective interaction of nuclei that is due to the change in the kinetic energy of their relative motion under the effect of the antisymmetrization operator is analyzed on the basis of a discrete representation of harmonic-oscillator states allowed by the Pauli exclusion principle. It is concluded that the bound state of the ¹²Be nucleus owes its origin to the impact of exchange effects on the operator of the kinetic energy of the relative motion of the neutron and the ¹¹Be nucleus. The structure of the ¹²Be ground state is discussed in the approximation of two coupled cluster configurations. The cross section for the inelastic-scattering reaction ¹¹Be(n, ² n)¹⁰Be is estimated.     

Deep inelastic scattering: <Emphasis Type="Italic">Q</Emphasis><Superscript>2</Superscript> dependence of structure functions

Some characteristic features of deep inelastic scattering are reviewed. In particular, the Q ² dependence of structure functions is described in detail especially in the region of small values of the Bjorken variable x. The technique of calculation of the coefficient functions of the Wilson expansion is also discussed. The importance of the use of a scheme-independent perturbation theory in the kinematical regions in which the nonleading correction to observables is numerically large is emphasized.     

Diffractive scattering of <Superscript>7</Superscript>Be and <Superscript>8</Superscript>B nuclei by <Superscript>12</Superscript>C nuclei

A theory of the diffractive scattering of loosely bound three-cluster nuclei by nuclei was developed with allowance for Coulomb interaction. The differential cross sections for the scattering of projectile exotic nuclei ⁷Be and ⁸B by ¹²C nuclei at an energy of 40 MeV per nucleon were calculated within the proposed formalism. The results describe satisfactorily relevant experimental data.     

Neutron transition densities for the 2<Superscript> + </Superscript>-8<Superscript> + </Superscript> multiplet of states in <Superscript>90</Superscript>Zr

Neutron transition densities for the 2 ⁺ -8 ⁺ levels in ⁹⁰Zr were extracted in the process of analyzing scattering at 400 MeV. They were compared with the calculated neutron transition densities and with the experimental proton transition densities. Radial distributions of the experimental neutron and proton transition densities for each state were found to be different.Received: 9 January 2004, Revised: 4 April 2004, Published online: 14 September 2004PACS: 25.40.Ep Inelastic proton scattering - 21.10.-k Properties of nuclei; nuclear energy levels     

Description of elastic scattering in the <Superscript>16</Superscript>O + <Superscript>16</Superscript>O and <Superscript>16</Superscript>O + <Superscript>12</Superscript>C systems

The objective of the present study was to describe more precisely experimental data on elastic scattering in the ¹⁶O + ¹⁶O system at E _lab = 124, 145, 250, 350, and 480 MeV and in the ¹⁶O + ¹²C system at E _lab = 132, 170, 181, 200, 230, 260, and 281 MeV. The role of exchange interaction in the region of backward angles is investigated. The coefficient of incompressibility of nuclear matter is estimated at K = 205 MeV ± 15%.     

Semiclassical description of the <Superscript>6</Superscript>He+<Superscript>12</Superscript>C elastic scattering

The results of the elastic scattering of ⁶He+¹²C systemat E _Lab = 18 MeV by using the barrier and internal wave decomposition of the S-matrix element within the framework of the WKB method are presented. This is the first detailed study for the interaction of the exotic ⁶He nucleus on different stable nuclei by using a semiclassicalmethod. In this paper, we show that in order to obtain the elastic scattering cross section of the ⁶He+¹²C systemat energies close to the Coulomb barrier, it is vitally important to take into account the inner complex turning points in the calculations and the tunneling effects play a crucial role to explain the experimental data. The semiclassical results are compared with the experimental data as well as the quantum-mechanical one.     

Analysis of <Superscript>4</Superscript>He+<Superscript>40</Superscript>Ca and <Superscript>4</Superscript>He+<Superscript>44</Superscript>Ti scattering using different optical model potentials

Elastic scattering of ⁴He+⁴⁰Ca and ⁴He+⁴⁴Ti reactions at backward angles has been analyzed using two differentmodels, microscopic and semimicroscopic folding potentials. The derived real potentials supplemented with phenomenological Woods–Saxon imaginary potentials, provide good agreement with the experimental data at energy E_c.m. = 21.8 MeV without need to renormalize the potentials. Coupledchannels calculations are used to extract the inelastic scattering cross section to the low-lying state 2+ (1.083 MeV) of ⁴⁴Ti. The deformation length is obtained and compared with the electromagnetic measurement values as well as those obtained from previous studies.     

Neutron sensitivity and detection efficiency of <Superscript>3</Superscript>He and <Superscript>10</Superscript>BF<Subscript>3</Subscript> counters

An analytic relationship between the efficiency, sensitivity, and the coefficient of working-isotope utilization is established for gas-filled cylindrical thermal-neutron counters. This dependence is expressed in terms of the ratio of the characteristic length of a counter to its diameter. The characteristic size is introduced as the ratio of the total absorption cross section to the length of the counter. The parameters of basic ³He and ¹⁰BF₃ counters used in NM-64 neutron monitors are calculated.     

A study of semi-classical processes in the elastic scattering of <Superscript>32</Superscript>S by <Superscript>64</Superscript>Ni and <Superscript>58</Superscript>Ni by <Superscript>27</Superscript>Al

In order to determine the extent of the presence of semi-classical phenomena such as Fresnel and Fraunhofer patterns etc., we have analyzed the elastic scattering of ³²S by ⁶⁴Ni and ⁵⁸Ni by ²⁷Al using the McIntyre parametrization at several energies. The theoretical approach can reasonably account for the general pattern of the data, thus allowing us to extract the parameters pertinent to these semi-classical processes. The scattering of ⁵⁸Ni by ²⁷Al at 220, 185, 170, 160 and 155 MeV laboratory energies, exhibits features expected from the strong absorption model (SAM). However, the features of the scattering of ³²S by ⁶⁴Ni at 150, 108, 98, 93, 91, 88 and 82 MeV laboratory energies have significant deviation from the expected pattern of SAM.