Experimental Realization of a New Type of Crystalline Undulator

A new scheme of making crystalline undulators was recently proposed and investigated theoretically by Andriy Kostyuk, concluding that a new type of crystalline undulator would be not only viable, but better than the previous scheme. This article describes the first experimental measurement of such a crystalline undulator, produced by using ${\mathrm{Si}}_{1-x}{\mathrm{Ge}}_x$-graded composition and measured at the Mainzer Microtron facility at beam energies of 600 and 855 MeV. We also present theoretical models developed to compare with the experimental data.

Figure 1

The experimental setup. The electron beam enters the crystalline target before being bent away by the first magnet. The emitted radiation travels through the collimator and is detected by an NaI detector.

Figure 2

The photon number spectra for channeling along the (110) plane and particle penetration in a random orientation, subtracted the background for the 600-MeV data.

Figure 3

The photon number spectra for channeling along the (110) plane and particle penetration in a random orientation, subtracted the background for the 855-MeV data.

Figure 4

Comparison of theoretical and experimental radiation yield for the 600-MeV data.

Figure 5

Comparison of theoretical and experimental radiation yield for the 855-MeV data.

Figure 6

Calculated radiation spectra for different values of the bending amplitude $a_u$ at 600-MeV electron energy using the screened Coulomb potential.

Figure 7

Calculated radiation spectra for different values of the bending amplitude $a_u$ at 600-MeV electron energy using the continuum potential. The bending amplitude goes from 0 Å to 0.45 Å in steps of 0.05 Å.