Magnetic angle changer—a new device allowing extension of electron–photon coincidence measurements to arbitrarily large electron scattering angles

Abstract

The electron–photon coincidence technique has been used as the most sensitive tool for investigating inelastic collisions of atoms with electrons and heavy particles and led to new insights into collision dynamics theory. However, for purely geometrical reasons, due to finite sizes of the electron energy analysers and electron beam sources, the measurements have not been carried out for the largest scattering angles. We present a novel system for electron–photon coincidence experiments on electron inelastic scattering with the magnetic angle changer allowing determination of excitation parameters at arbitrarily large scattering angles. As shown by experimental tests, our device can be successfully used in the electron–photon coincidence experiment and it has unprecedented efficacy—deflection angle up to 60° for 100 eV electrons, without a ferromagnetic core.

Low energy super-elastic scattering studies of calcium over the complete angular range using a magnetic angle changing device

“…This Magnetic Angle Changing (MAC) device has now successfully been used in elastic and inelastic angular cross section studies from a number of different targets [21][22][23][24][25] and has also been used in (e,2e) ionization studies in a coplanar asymmetric geometry [26][27][28].…”

Magnetic Angle Changer for Studies of Electronically Excited Long-Living Atomic States

“…In experiments on the EICP measurements in a weak magnetic field, an additional effect analogous to a well-known Hanle effect [9] is present, which was described in detail in the past [10,11]. The phenomenon was initially observed as a modification of the polarization state of light resonantly scattered by atoms placed in a magnetic field [12].…”

“…There is a finite time interval between the collision act and photon emission, given by an exponential distribution described with the excited state's lifetime τ. This way, the precession of the charge cloud in the finite time leads to blurring the measurement results to Pl and γ values given with the expressions obtained by convolution of cloud rotation and exponential decay [10]:…”

Analysis of Radial Dependence of the Localized Magnetic Field using Artificial Neural Networks

“…In particular, the magnetic angle changer (MAC) device provides a powerful tool for the detection of over the full range of scattering electrons for electron-electron coincidence measurements [1][2][3][4][5][6][7][8]. The MAC device is combined by a pair of counterpropagating coils.…”