  This paper presents the results of measurements of fluorescing cerium-doped
yttrium aluminum garnet crystals after being irradiated by an accelerated
electron beam with energy of around 4 MeV. The measurements were performed
using the PHIL linear accelerator at LAL (France). We observe linear dependence
of the crystal emission to the electron beam charge and the isotropy of the
photon emission. We provide the calibration coefficients of the photon emission
depending on the charge of the accelerated electron beam for two crystals
originating from two different manufacturers.
