The concept of remote detection of concealed radioactive materials by using high-power THz radiation

This paper describes the progress in developing a high-power, sub-THz gyrotron with a pulsed solenoid and new results in elaborating the concept of THz gyrotron radiation for remote detection of concealed radioactive materials. The 0.67 THz gyrotron delivers more than 200 kW in 20-30 microsecond pulses and operates with the efficiency about 20%. New contributions to the development of the concept include: a) analysis of the propagation of gamma rays and production of free electrons in air, b) estimating the mass of radioactive material which can be detectable at a certain distance from the source, c) characterization of the breakdown-prone volume as the function of the THz power and polarization, crossing angles (in the case of crossing wave beams) and the atmospheric turbulence.