Influence of bending parameters on crystalline undulator radiation peak stability for 530 MeV positron channelling

We investigate the stability of crystalline undulator radiation (CUR) peaks emitted by 530 MeV positron channelling in periodically bent C(110) crystals with varying bending amplitudes and bending periods. Relativistic molecular dynamics simulations were performed to quantify how these parameters affect the intensity and position of the CUR peak. The continuous potential approximation was used to identify isolines of constant peak energy, providing a reference for regions of spectral stability. MD results show that increasing the bending amplitude shifts the CUR peak to lower photon energies, while decreasing the period shifts it to higher energies, with both trends accompanied by enhanced dechannelling. For crystal parameters similar to recent experiments conducted at the Mainz Mikrotron (MAMI), the simulated CUR peak appears near 0.515 MeV. These results demonstrate that the CUR peak remains stable across a broad range of bending amplitudes and periods, providing quantitative estimates of the sensitivity of the emitted radiation to variations in the crystal bending parameters.

Spectral distributions of crystalline undulator radiation for 530 MeV positrons for different bending profiles. The top row corresponds to the emission cone ${\theta }_0=133.8\mu \text{rad}\approx 0.139/\gamma$ , and the bottom row $5/\gamma \approx 4821\mu \text{rad}$ . The left column corresponds to a bending period of $\lambda =8.0\mu \text{m}$ , the middle column $6.5\mu \text{m}$ , and the right column $5.0\mu \text{m}$ . All cases show the same range of bending amplitudes a.

The online version contains supplementary material available at 10.1140/epjd/s10053-026-01227-7.