Measurement of angular distribution of soft X-ray radiation from thin targets in the tabletop storage ring MIRRORCLE-20SX

Abstract

The only available tabletop electron storage rings are the machines from the MIRRORCLE series. The electrons are accelerated in a microtron and injected into the storage ring. During its circulation, each electron passes through a tiny target many times, emitting a photon beam. Both the spectrum and the angular distribution of the radiation depend on the material, the thickness and the shape of the target. In this paper measured angular distributions of the radiation from several different targets in the magnetic field of the 20 MeV storage ring MIRRORCLE-20SX are presented. The detector comprises a 3 mm × 3 mm × 8.5 µm plastic scintillator (PS) coupled to a photomultiplier by a bundle of optical fibers. The output of the photomultiplier is digitized by an IF converter. This detector is sensitive mostly to soft X-ray radiation, and its PS is moved by a mechanical system in a plane perpendicular to the radiation axis. The measured angular distributions for Mo and Sn targets contain an annulus which is attributed to transition radiation. The angular distributions for Al, carbon nanotube and diamond-like carbon (DLC) targets show some suppression of the radiation along the magnetic field. This is the first evidence of observation of the angular distribution of synchrotron Cherenkov radiation, which represents Cherenkov radiation in a magnetic field. The power radiated from the DLC target is estimated.

Observation of soft X-ray Cherenkov radiation in Be and Si foils

“…Among the recent experimental studies, the results that was observed on the inner electron beam of the special synchrotron "MIRRORCLE-20" [19] are of particular interest. In this experimental studies, an anomalously high angular density of soft X-ray radiation was observed in the plane perpendicular to the magnetic field of the synchrotron.…”

Observation of soft X-ray Cherenkov radiation in Al

“…For example, the experimental Cherenkov angles for carbon and Si turned out to be the same, which does not agree with the theory. Among the recent experimental studies, the results that was observed on the inner electron beam of the special synchrotron "MIRRORCLE-20" [19] are of particular interest. In this experimental studies, an anomalously high angular density of soft X-ray radiation was observed in the plane perpendicular to the magnetic field of the synchrotron.…”

MIRRORCLE type tabletop synchrotron light source realizing micron‐order focus point

“…We are concerned on Compton back scattering using a storage ring, [1] but we sought that monochromatic X-ray is not useful for spectroscopy, or protein crystallography. We choose the mechanisms using the collision of relativistic electron and target such as Bremsstrahlung [2] for hard X-ray or synchrotron Cherenkov radiation [3] for soft X-ray. MIRRORCLE-CV series is an X-ray source based on a low-energy electron storage ring.…”