A study of photoelectron angular distributions in xenon using a new magnetic angle-changing technique

Abstract

The angular distribution parameter for the Xe ion state has been studied for the Xe autoionization resonances in the energy range between 20 and 24 eV using tunable synchrotron radiation from the Daresbury Laboratory SRS. A new magnetic angle-changing technique has been used and is reported for the first time in photoionization measurements. This technique allows the angular measurements to be made without any movement of the electron spectrometer. The present measurements have been made as continuous functions of both photon energy and photoelectron ejection angle which highlights the dramatic effect of those autoionizing resonances on the angular distribution parameter.

Experimental investigation of nondipole effects in photoemission at the advanced light source

“…Measurements were made over the 26-140 eV photon-energy range at Wisconsin's Synchrotron Radiation Center (SRC) with an instrument described elsewhere . Other experimental and theoretical results have been reported in Lagutin et al (1996), Becker and Shirley (1996), and Cubric et al (1997). The angle-resolved TOF spectra were calibrated using neon 2p photolines, and neon 2s photoelectrons were used to determine the degree of linear polarization of the synchrotron light ð499:9%Þ.…”

Negative ion resonance measurements in the autoionizing region of helium measured across the complete angular scattering range (0°–180°)

“…One solution to this problem, developed by Cubric et al [46], is to incorporate a soft-iron core within the solenoids of the MAC. This significantly increases the magnetic field in the device, and hence greatly extends the range of electron energies that can be used.…”

Iron-cored coil system for the measurement of angular distributions of charged particles

“…It is necessary for the field to be localized in the region of the target in order not to disturb the action of electrostatic devices that are used for energy selection or analysis. In the previous applications of the technique [1][2][3][4] the magnetic field has been produced by concentric iron-free solenoids and the localization has been achieved by ensuring that the overall magnetic dipole moment of system is zero ͑see below͒. Because the overall magnetic quadrupole moment of a system of cylindrical solenoids is automatically zero, 1 the external magnetic field then decreases asymptotically as the inverse fifth power of the distance from the center of the system.…”

“…The technique has been successfully applied to angular distribution measurements over the full angular range for the nϭ2 excited states of He and also to measurements of photoelectron angular distributions. 3,4 The magnetic field in those experiments was produced by a set of solenoids. They had a typical radius of 15 mm.…”