7th International Workshop on Ring Imaging Cherenkov detectors (RICH 2010)

Correlation Phenomena in the Cherenkov Radiation of multiply charged Ions

6 mai 2010, 10:00

20m

Oustau Calendal Conference Center

Poster Cherenkov imaging in particle and nuclear physics experiments Poster Session 2 (Summary)

Orateur

Prof. Vyacheslav Malyshevsky (Southern Federal University)

Description

Correlation phenomena occurring in Cherenkov radiation are considered which are related to fluctuations of the charge states of multiply charged accelerated ions in a medium. The additional correlation contribution to the radiation is determined by the root-mean-square deviation of the ion charge from its equilibrium value and is responsible for the nonzero radiation yield in the event that the threshold condition is not fulfilled. Averaging the energy absorbed by the medium over the equilibrium charge state distribution will yield in this case correlation phenomena in the stopping power of an ion and in the generated electromagnetic radiation. The effect of these phenomena on Cherenkov radiation was considered for the first time by one of the authors in Ref. Physics Letters A, 372, 2133, 2008. The effect of charge exchange on Cherenkov radiation can be qualitatively described based on the Huygens principle. The field component with frequency ω of a particle moving in a medium can be represented as a superposition of the fields of oscillators of the same frequency arranged along the particle trajectory. If the particle charge is stepwise changed on some sections of the trajectory, this will change the energy of the particle interaction with the medium and the amplitudes of the oscillator fields. As a result, the interference of the oscillator fields within the coherence length from the trajectory sections corresponding to different charge states will incompletely damp the resulting field outside the Cherenkov radiation cone. If the charge fluctuations are random, this results in smearing of the radiation wave front and in transformation of the angular spectral density. Numerical estimates of the radiation yield of heavy ions in the optical and X-ray frequency ranges are given.