Dependence of effective spectrum width of synchrotron radiation on particle energy V. G. Bagrov, D. M. Gitman, A. D. Levin, A. S. Loginov and A. D. Saprykin Eur. Phys. J. C, 77 5 (2017) 345 Published online: 24 May 2017 DOI: 10.1140/epjc/s10052-017-4880-z