Simulation code for modeling of coherent effects of radiation generation in oriented crystals

We present the crystalrad simulation code, combining all the features of the crystal simulation code for simulations of charged particles trajectories in a bent crystal and the radcharm++ code for calculation of the radiation spectrum. The crystalrad code is based on Monte Carlo simulations of trajectories in the planar and axial electric field either in a straight, bent, or periodically bent crystal taking into account multiple and single Coulomb scattering on nuclei and electrons, nuclear scattering and ionization energy losses. The trajectories simulated are used for calculation of radiation spectra by the Baier-Katkov method. We compare our simulations with experimental data taken at MAMI (MAinzer MIkrotron) as well as give an example for a possible future study with sub-GeV electrons interacting with Si bent crystals.

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Figure 1

Averaged potential examples. Top: interplanar potential in a silicon crystal between (111) crystal planes, calculated in the models of the harmonic, Molière and Doyle-Terner potentials. Bottom: interaxial potential in a silicon crystal between $⟨111⟩$ crystal axes in the model of Doyle-Terner.

Figure 2

Interplanar nuclear (top) and electron (bottom) densities in a silicon (solid) and germanium (dashed) crystals between (110) crystal planes.

Figure 3

The algorithm of crystalrad simulation code.

Figure 4

Simulated (points) and experimental (lines) radiation spectra of 855 MeV electrons in Si bent crystal $30.5\mu \mathrm{m}$ thick with 33.5 mm bending radius for crystal-to-beam perfect alignment $0\mu \mathrm{rad}$ (channeling) and at $493\mu \mathrm{rad}$ (volume reflection). The beam angular divergence is $30\mu \mathrm{rad}$.

Figure 5

Simulated radiation spectra of 855 MeV electrons in a Si bent crystal $15\mu \mathrm{m}$ thick in dependence on the ratio of the crystal radius and its critical value. The beam angular divergence is $21.4\mu \mathrm{rad}$, the angle of crystal alignment is 0.