Table of contents

A secondary target Energy Dispersive X-ray Fluorescence spectrometer with three axial geometry has been used in multielement analysis of aerosols. A new type of monitoring system has been designed to monitor the flow of secondary photons and thus minimize the influence of time variation in the X-ray intensity. The aerosols were divided in two size fractions by means of a virtual impactor and deposited on filters. The absolute concentrations of the different elements were obtained by use of standard samples with known element concentrations. Detection limits for sixteen elements are given and are in the order of ng per cm². The method has been applied to aerosols of widely varying composition and concentration in ambient atmosphere and industrial environment.

The present analysis of proton-emulsion nuclei interactions at 400 GeV supports the correlation between the grey tracks and the hadron-nucleon collisions inside the nucleus as proposed by Andersson et al. This model has been extended to get the angular distribution of fast secondaries. The extended model explains satisfactorily the experimental results on the proton-nucleon and proton-emulsion nuclei interactions at 400 GeV. An attempt has also been made to estimate the energy of the slow hadron.

It is found that the concept of pseudo-spin and pseudo-oscillator quantum numbers, introduced by previous authors, can be helpful in understanding the qualitative features of quasiparticle motion in rotating potentials, for the orbits with normal parity (excluding the high j orbits). In the first part of the paper, the use of pseudo-spin in static deformed potentials is briefly reviewed.

Starting from the full differential cross-section of e^-e⁺ → qg for vector and scalar gluons, neglecting neutral current effects, we investigate the sensitivity of various one-dimensional distributions to the gluon spin. Variables which take into account not only the Dalitz-plot density, but also angular distributions and (eventual) beam polarization are more effective. In addition we consider the angular distributions of the energy-ordered jet axes and of the normal to the event plane. The probabilities for the jets to originate from a gluon (or quark) are also given.

The contributions of core polarization terms (other than the Auerbach-Kahana-Weneser (AKW) effect) to Coulomb displacement energies of mirror nuclei near A = 16 and A = 40 are examined within the particlevibration coupling model. The parameters of the model are determined using updated data on the locations and strengths of multipole core excitations. In the absence of relevant data an energy-weighted sum rule (EWSR) is exploited. Taking into account multipole excitations up to L = 5 and subtracting the contributions which are due to short-range correlations, significant contributions (1-3%) to ΔE_c are found. These corrections arise from particle coupling to low-lying collective states (long-range correlations). The implications of these results on the Coulomb energy problem are discussed.

Spectra of Cl through Ti (excluding Ar) were produced with 1 GW 15 ns) pulses from a Nd-glass laser impinging on solid targets, and observed with a 10.7 m grazing incidence spectrograph. Transition arrays 2s^m2pⁿ-2s^m-12pⁿ⁺¹ in the B I isoelectric sequence were recorded. Two intersystem transitions 2s2p²⁴P-2p³²D of Sc XVII were identified, and improved wavelength measurements of allowed lines were made for each spectrum. From a least squares fit of radial energy integrals to Sc XVII energy levels, percentage compositions of the levels were obtained.

The spectrum of two times ionized oxygen, O III, has been observed with a theta-pinch discharge as a light source. About 750 lines have been measured in the wavelength region 500-8500 A; about 450 of these are new lines. By using only lines above 500 A the whole energy-level system has been recalculated. On the basis of the new measurements, calculated wavelengths are given for 147 lines in the region 228-500 A, suitable as reference lines.

By applying the polarization formula to the hydrogen-like levels, the ionization limit has been determined to 443 084.7 ± 2 cm^-1.

The energy and angular distribution of electrons emitted from the K- and L-shell of relativistic atoms is evaluated in the semiclassical theory by means of the united-atom description. It is shown that for the high electron energies considered here the angular anisotropy is mostly small and has a dipole shape. For certain systems the electrons from the 2p_1/2 and 2p_3/2 subshells are preferably ejected in the backward direction. Detailed calculations are presented for the (S, Pb), (Ni, Pb) and (Pb, Sn) systems and compared with experimental data.

The exergy in an arbitrary spectrum of incoherent electromagnetic radiation is derived. For each wave vector of the radiation a quality factor is defined. The mean quality factor for black-body radiation (1 - 4/3(T₀/T) + 1/3(T₀/T)⁴) is obtained as a special case.

An investigation is made of the pitch angle diffusion and slowing down of α-particles in magnetically confined fusion plasmas. In particular, the diffusive loss of particles and the associated energy loss are determined for different kinds of velocity space loss regions, corresponding to the loss cone of an open field line system as well as to the toroidal field ripple and banana orbits in a Tokamak configuration. The analysis employs the approximate Goodman integral method for the investigation of the Fokker-Planck equation, which determines the dynamics of the α-particles.

We have investigated the effects of presence of a colder species of electron in the propagation of ion acoustic waves retaining third order terms in the reductive perturbation method. The stationary wave solution for the electric potential has been obtained. Both potential hump and potential dip are found to exist depending on the densities and temperatures of the two electron components. It has been found that the presence of a colder species of electron decreases the velocity and increases the width of the solitary waves.

The anisotropic antiferromagnetic chain at T = 0 is studied using the renormalization group method for the perturbation expansion of the Dyson-Maleev spin wave model in the inverse of the spin 1/S. We show that the momentum shell recursion relations for the anisotropic coupling constants and for 2/S are similar to those of the anisotropic non-linear sigma-model at two dimensions when the temperature T is replaced by 2/S in the antiferromagnetic chain.