Cerenkov effect

Cerenkov radiation accounts for a very minor part of the energy loss of fast electrons. Its main importance is for monitoring purposes and establishment of a reference time, since it is produced almost instantaneously with the passage of the particle. Katsumura et al. (1985) have observed a very fast rise of solute fluorescence attributable to the Cerenkov effect the G value for this process is estimated to be -0.02. 

The Cerenkov effect described in 6.4.3 can be used for detection of high energy jS-radiation because the velocity of the nuclear particle must exceed the ratio dn, where n is the refractive index of the absorber. 

Detectors using gallium > 0.2 MeV), chlorine (Ej/ 0.8 MeV), and Cerenkov effect in water > 7 MeV) measure significantly lower neutrino rates than are predicted from solar models. The deficit in the solar neutrino flux compared with solar model calculations could be explained by oscillations with Am < 10 eV causing the disappearance of Pq. 

Cerenkov effect for high energy particles of a proton accelerator according to Teichner et al. (316). Such low densities were achieved by hydrolyzing ethyl silicate... 

Industrial irradiators that sterilize medical products and food use a source ruck filled with pencils of cobalt-60. The blue glow, caused by electrons slowing in water, is known as the Cerenkov effect. 

The jitter between the laser pulse and the electron pulse was estimated from the measurement using a streak camera (C1370, Hamamatsu Photonics Co. Ltd.), because the jitter is one of important factors that decide the time resolution of the pulse radiolysis. The jitter was several picoseconds. To avoid effects of the jitter on the time resolution, a jitter compensation system was designed [74]. The time interval between the electron pulse (Cerenkov light) and the laser pulse was measured by the streak camera at every shot. The Cerenkov radiation was induced by the electron pulse in air at the end of the beam line. The laser pulse was separated from the analyzing light by a half mirror. The precious time interval could be... 

Morgan TL, Redpath JL, Ward JF (1984a) Induction of lethal damage in E. coli by Cerenkov emission associated with high-energy X-rays the effect of bromouracil substitution. Int J Radiat Biol 45 217-226... 

Fig. 5. Effective index of the TMO and TM, modes at both the fundamental and harmonic frequencies versus film thickness for a slab waveguide. MD identifies modal dispersion wavevector matching for TM0(ft>)—>TM1(2ft)). The solid vertical arrow identifies QPM for TM0(a>)—>TM0(2a>). The region C—> identifies film thicknesses for which Cerenkov SHG...

Figure 2. Detection principle of an underwater neutrino telescope. Astrophysical neutrinos can reach the Earth and interact in water or in rocks generating an upgoing muon. An array of 5000 optical detectors tracks Cerenkov photons generated along the muon track. A water shielding > 3000 m is effective to reduce the atmospheric fi background, allowing the reconstruction of upgoing muon tracks.

In the Cerenkov-type SHG the fundamental wave is guided in thin film, while the harmonic wave is outcoupled into the substrate (Fig. 44). It requires that the refractive indices of fhe subsfrafe af a) and 2co frequencies and the effective... 

In the time resolved Raman measurements on radiation-chemical systems, optical multichannel detection offers some distinct advantages over the photon counting techniques. The intense Cerenkov pulse associated with the electron pulse is intense enough to saturate a photomultiplier tube (PMT). In an optical multichannel detector, the Cerenkov pulse can be effectively gated off by turning the detector on within a few nanoseconds after the electron pulse is over. Apart from this, such spectra are free from the variation in electron or laser pulse intensity unlike the spectra obtained by single channel devices. 

Placement of the sample photodiode at a distance from the sample allows Cerenkov light from the sample to diverge, reducing its effect on the absorbance measurement. Absorbance measurements can be normalized using the Faraday cup readings to correct for fluctuations in beam intensity. 

A new wavefront BC of the second-harmonic wave is obtained (Cerenkov radiation). Vp and are the velocities of the fundamental mode in the film and the second-harmonic wave in the substrate, respectively and Neff is the effective refractive index of the fundamental mode in the waveguide. The condition (1) is fulfllled for v > v . Generally Clerenkov radiation is generated for... 

As was discussed above the necessary condition for Cerenkov-type phase-matched frequency-doubling is that the effective refractive index of the fundamental mode is smaller than the refractive index of the substrate at 2flX This condition can be fulfilled for DCANP deposited on pyrex. Table 1 lists the refractive indices at the fundamental and the second-harmonic wavelengths, the thicknesses t of the films used in our experiments and the calculated and measured Cerenkov angles. As can be seen from Table 1 the Cerenkov angles 0 co/c and Q meas are in agreement within the experimental errors. 

This electromagnetic (shock) wave is the radiation that was first observed by Cerenkov. It is a classical electromagnetic effect that depends solely on the velocity of the particle and the index of refraction of the material. The refractive index depends upon the wavelength (or frequency) of the light, and the effect occurs only for those wavelengths that give real values of the angle in Eq. (23.I)... 

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