New module for channeling radiation simulation in Geant4

We present a new C++ module for simulation of channeling radiation to be implemented in Geant4 as a discrete physical process. The module allows simulation of channeling radiation from relativistic electrons and positrons with energies above 100 MeV for various types of single crystals. In this paper, we simulate planar channeling radiation applying the classical approach in the dipole approximation as a first attempt not yet considering other contributory processes. Simulation results are proved to be in a rather good agreement with experimental data.

Cherenkov-channeling radiation by relativistic muons in crystals

In this work we analyse Cherenkov radiation by relativistic muons, positive and negative, channeled in optically transparent diamond and silicon crystals in comparison with ordinary Cherenkov radiation. We have shown that the maxima in the spectral angular distributions for both types of radiation are revealed at the derivative extrema for the media refractive index, while, due to the difference in scattering of positively and negatively charged particles at crystal channeling, the number of Cherenkov photons emitted by channeled positive muons might be over the one for negative muons. We have demonstrated that Cherenkov radiation by quasi free projectiles is described as one limiting approximation of a general expression for Cherenkov radiation by channeled projectiles, which takes into account non-zero derivative of the refractive index. The last may result in essential increase of radiation intensity.

Experience with crystals at Fermilab accelerators

Crystals were used at Fermilab accelerators for slow extraction and halo collimation in the Tevatron collider, and for channeling radiation generation experiments at the FAST electron linac facility. Here we overview past experience and major outcomes of these studies and discuss opportunities for new crystal acceleration R&D program.