Polarimetry in electron–photon coincidence studies

Excitation of He(31 D) by electron impact

“…The visible red (667.8 nm) photons from the 31D--*21P decay passed through an optical tens (entrance solid angle 0.144 sr perpendicular and 0.1 sr parallel to the scattering plane) to form a parallel beam of light which was subsequently directed onto the appropriate retarder and linear polarizer combination followed by an interference filter and the cooled photomultiplier tubes (EMI 9863QB) operated in the pulse counting mode. The retardance and the handedness of the retarder were determined as described by Wedding et al [14]. For circular polarization measurements, two retarders were used; the larger having a diameter of 4.9 crn permitted the increase of the entrance solid angle from originally 0.048 sr to 0.144 sr.…”

Preparation of Al–O–N Films by Electron Cyclotron Resonance Plasma-Assisted Chemical Vapor Deposition

“…If the retardation phase angle is not exactly equal to π then elliptically polarized laser light interacts with the target atom beam and the term involving L + perp , in equation (3), makes a contribution to the scattering signal. For the present experiments, we determined the retardation phase angle of the plate by a procedure described in detail by Wedding et al (1991). This involved placing the retardation plate between two Glan-Taylor polarizing prisms, passing laser light (tuned to the Ba resonance wavelength) through the combination and measuring the transmitted light intensity as a function of rotation of the retardation plate.…”

“…This involved placing the retardation plate between two Glan-Taylor polarizing prisms, passing laser light (tuned to the Ba resonance wavelength) through the combination and measuring the transmitted light intensity as a function of rotation of the retardation plate. Equation (9) of Wedding et al (1991) was used to extract cos δ with the transmission axes of the polarizers oriented at 45 • to each other, in one set of measurements, and at 0 • to each other (parallel axes) in a second set of measurements. The results of these measurements gave cos δ = 0.970 ± 0.002 in contrast to an ideal half-wave plate for which cos δ = 1.…”

Alignment and orientation of Ar+ in He+-Ar collisions

“…1. Corrections to the polarized radiation intensities due to a detailed calibration of the transmission properties of the linear polarizer and the measured value of the phase shift and fast axis direction of the near-quarter wave plate were incorporated into the data analysis [ 13,14].…”