The polarization of bremsstrahlung from radiative ionization induced by relativistic highly charged projectiles

Abstract

Based on inverse kinematics the close relation between radiative electron capture to the projectile continuum, calculated within the impulse approximation, and electron-nucleus bremsstrahlung is shown. Particular emphasis is laid on the short-wavelength limit corresponding to cusp-electron emission in the target frame of reference. Differential cross sections and the degree of photon polarization are calculated for the coincident emission of electron and photon. Coplanar and non-coplanar geometries are considered, and the polarization is compared with that obtained from experiments on the elementary bremsstrahlung process and on radiative electron capture to bound states.

Radiative-electron-capture-to-continuum cusp inU88++N2collisions and the high-energy endpoint of electron-nucleus bremsstrahlung

“…The experimental data have been compared with the bremsstrahlung theory developed by Surzhykov and Yerokhin using fully relativistic Dirac wave functions [16,38] as well as with the RECC theory developed by Jakubassa-Amundsen applying SM wave functions [26][27][28]. The results imply a measurement of the probability of populating a low-energy projectile-ion continuum state with a given energy E f under emission of a photon as a function of E f .…”

“…Inelastically scattered electrons with E f ≈ 0 in the (primed) reference frame of the ionic projectile travel parallel to the projectile after the collision, with an electron velocity v e that is similar to the projectile velocity v p ≈ v e in the (unprimed) laboratory frame. This process, closely related to the fundamental process of electron-nucleus bremsstrahlung, is termed radiative electron capture to continuum (RECC) or radiative ionization [26][27][28]. RECC in turn is closely related to radiative electron capture to bound states (REC) [29,30], analog to the described relationship between bremsstrahlung and radiative recombination.…”

Polarization of atomic bremsstrahlung in coincidence studies

“…Most of the studies of atomic bremsstrahlung in the past were dedicated to the properties of the emitted photons, while the scattered electrons remained unobserved. In these works, the angular distribution of the emitted radiation [1][2][3][4][5][6] and its polarization [7][8][9] was investigated. Due to experimental limitations, less attention was paid to setups where the emitted photons and the scattered electrons are observed in coincidence.…”

“…Scaled triple-differential bremsstrahlung cross section(7) as a function of the photon emission angle θ k . The calculations have been performed for the scattering of initially unpolarized electrons on neutral silver atoms, for the initial and final electron energies ε i = 180 keV and ε f = 100 keV and the fixed electron scattering angles ϕ p = 0 • and θ p = 30 • .…”

Radiative electron capture to the continuum in U89++N2 collisions: Experiment and theory

“…This process is termed radiative electron capture to continuum (RECC), in analogy to the radiative electron capture (REC), which is the capture of a quasifree target electron into a bound state of the projectile ion under emission of a photon [21]. RECC was first investigated theoretically by Jakubassa-Amundsen [22][23][24][25][26], and first coincidence measurements were pioneered by Nofal et al [27]. In Refs.…”