Gamma-ray Cherenkov-transition radiation

The spectral and angular distributions as well as the total number of photons of gamma-ray Cherenkov-transition radiation (GCTR) produced by charged particles in the photon energy region ${}\sim(0.8\text{--}2)\ \text{MeV}$ are calculated. For this purpose we used the experimental results of the recent discovery according to which in the above-mentioned region the measured refractive index of silicon as well as the theoretically calculated refractive index of gold are greater than 1. Using the results of the carried out numerical calculations an experimental arrangement is discussed for the observation and experimental study of the GCTR. As our results show the GCTR photon yield is about one order of magnitude higher than the background bremsstrahlung yield. Some applications of GCTR, in particular, for comparatively easy search of new materials with refractive index $n(\omega )>1$ , are proposed