Electron Beam Monitor Based on Cherenkov Counter

Monitoring of a Photon Beam

“…Monitor (6) on the trajectory of the photon beam is turned by an angle Θ ≈ 40° from the relatively to the vertical axis Y (Fig. 2).…”

“…The features of using Cherenkov radiation for photon beam monitoring are: 1. low efficiency of photons interaction with material in comparison with the electrons interaction (less than ~10 3 -10 4 times), that makes it possible to use the Cherenkov counter for monitoring photon beams with a wide range of intensities 10 6 -10 10 γ/s (noninvasive monitoring system where the photon beam practically does not experience changes [4]); 2. fast time of formation of the Cherenkov pulses in the radiator compared, for example, to the scintillation one (~3-5 times), which is necessary at high beam intensity; 3. radiation resistance of the radiator (quartz glass, organic glass) compared with the scintillator (polystyrene) above. The most important thing is the proportional dependence of the Cherenkov photons number on the number of e + e‾ pairs converted in the substance of the counter, that makes it possible to compare the number of registered e + e‾ pairs to the number of photons passed through it and the total intensity of the photon beam [5,6]. The estimation shows that the number of Cherenkov photons passing through organic glass with a thickness of 1 cm of a photon beam with an intensity of ~10 9 γ/s is N chph ~ 5×10 7 -5×10 8 photons/s (taking into account the passage of two particles -an electronpositron pair), which is quite reasonable for creating a monitoring system [4,6,7].…”

“…The most important thing is the proportional dependence of the Cherenkov photons number on the number of e + e‾ pairs converted in the substance of the counter, that makes it possible to compare the number of registered e + e‾ pairs to the number of photons passed through it and the total intensity of the photon beam [5,6]. The estimation shows that the number of Cherenkov photons passing through organic glass with a thickness of 1 cm of a photon beam with an intensity of ~10 9 γ/s is N chph ~ 5×10 7 -5×10 8 photons/s (taking into account the passage of two particles -an electronpositron pair), which is quite reasonable for creating a monitoring system [4,6,7].…”