Radiative electron capture as a tunable source of highly linearly polarized x rays

Abstract

The radiative electron capture (REC) into the K shell of bare Xe ions colliding with a hydrogen gas target has been investigated. In this study, the degree of linear polarization of the K-REC radiation was measured and compared with rigorous relativistic calculations as well as with the previous results recorded for U 92+ . Owing to the improved detector technology, a significant gain in precision of the present polarization measurement is achieved compared to the previously published results. The obtained data confirms that for medium-Z ions such as Xe, the REC process is a source of highly polarized x rays which can easily be tuned with respect to the degree of linear polarization and the photon energy. We argue, in particular, that for relatively low energies the photons emitted under large angles are almost fully linear polarized.

Hyperfine-induced effects on Kα1 linear polarization following electron-impact excitation of heliumlike Tl79+ ions with nuclear spin I=1/2

“…As widely used experimental facilities at present, both electron beam ion traps and ion storage rings can provide nearly unidirectional and monoenergetic electron or ion beams [6,7]. When combined with modern high-resolution x-ray spectrometers or polarimeters, they were often employed to study angular distribution and linear polarization of characteristic x-ray lines emitted following various relativistic electron-ion collision processes, such as, electron-impact excitation (EIE) [8][9][10][11][12][13][14][15][16][17], dielectronic recombination [18][19][20][21][22][23][24][25][26], radiative electron capture (REC) [27][28][29][30][31], and nonradiative electron capture [32,33].…”

Investigation of two-photon 2s -> 1s decay in one-electron and one-muon ions

“…Recently it was reported that the detector technology for the measurement of the linear photon polarization (appearing in the Kshell radiative electron capture by heavy ions) was significantly improved [39].…”

Possible Polarization Measurements in Elastic Scattering at the Gamma Factory Utilizing a 2D Sensitive Strip Detector as Dedicated Compton Polarimeter

“…[ 1,2 ] But also in the laboratory it is desirable and often necessary to take into account the polarization characteristics of incoming and outgoing particles to provide the most rigorous tests of our theoretical understanding of the underlying processes. A lot of radiative processes, such as X‐ray scattering, [ 3,4 ] ion–atom collisions [ 5 ] and radiative electron capture, [ 6 ] exhibit distinct polarization features, thus a complete measurement must also include the polarization analysis of the process. Moreover, it was recently shown that X‐ray polarimetry can also be used as a tool for monitoring the polarization of particle beams, such as electrons [ 7 ] or ions.…”

“…Within the Stored Particles Atomic Physics Research Collaboration (SPARC), [ 10,11 ] covering atomic physics at GSI and FAIR, several X‐ray detectors were developed on the basis of large double‐sided segmented semiconductor crystals that are well suited for the application as Compton polarimeters. In the recent years, these detectors enabled measurements of the polarization transfer in Rayleigh scattering [ 12 ] as well as in the Bremsstrahlung process [ 7 ] as well as the polarization characteristics of photons emitted by radiative electron capture [ 6 ] , and of characteristic transitions within highly charged, heavy ions. [ 13 ] Recently, a dedicated Si(Li) Compton polarimeter was commissioned that features a significantly improved energy resolution of about 1 keV at a photon energy of 60 keV.…”