An apparatus for the production of circularly polarised VUV radiation

Abstract

An apparatus for the production of circularly polarised vacuum ultraviolet (vuv) radiation up to 9 eV is described. A photon beam of high intensity and polarisation is used for the photoionisation of atomic and molecular vapour beams in order to obtain spin-polarised photoelectrons. The radiation source and the polariser are discussed in detail. Results of intensity and polarisation measurements are presented.

Experimental determination of the phase differences of continuum wavefunctions describing the photoionisation process of xenon atoms. I. Measurements of the spin polarisations of photoelectrons and their comparison with theoretical results

“…In a test measurement using a double ionisation chamber of the Samson type (Samson 1964), the intensities of seven He and Ne resonance lines were found to be greater than lo1' photons/s (He I 8 x 10l2 photons/s, for example). The results of these absolute intensity measurements as well as a detailed description of the radiation source is given elsewhere (Heinzmann andSchonhense 1979, 1980). It is worth noting that the main reason for the high radiation intensities was the very high purity of the rare-gas discharges: the gas inlet system used only UHV components, the source was metal sealed and heatable, and the impurities in the gas flowing through the lamp were much smaller than 1 ppm.…”

“…Because the analyser cannot distinguish between circular and unpolarised radiation, the percentage of unpolarised background radiation was measured: in this measurement an additional MgF2 quarterwave plate, described by Heinzmann (1977), was used to transform the elliptical polarisation into a linear one which wa; analysed by the four-mirror arrangement. The maximum linear polarisation was found at a wavelength …”

Angle- and spin-resolved photoelectron spectroscopy in rotationally resolved photoionization of HI

“…The full line represents the result of a least-squares fit to (8). From the fit, the values for/max and I~in are determined, which then give the degree of linear polarization according to [38]:…”

“…It can be calculated from the constants/max and Imi n determined by the fit as follows [38] shown in Fig. 4b and c, respectively.…”

Experimental determination of the phase differences of continuum wavefunctions describing the photoionisation process of xenon atoms. II. Evaluation of the matrix elements and the phase differences and their comparison with data in the discrete spectral range in application of the multichannel quantum defect theory

“…It is the purpose of this paper and the following one (Heinzmann 1980, to be referred to as 11) to report on such experimentally obtained phase differences of continuum wavefunctions and matrix elements in the case of the photoionisation of xenon atoms. Xenon has been selected because the rare gases have a simple electronic structure in the ground state (filled shells, total angular momentum J = 0).…”