Analysis and measurement of optical properties and time characterization of silica aerogel used as a Cherenkov radiator

X-rays generated by high-energy pulsed electron sources can be utilized in tumor treatment. The time spectrum measurement of pulsed electron sources enables precise treatment and provides feedback to the design and construction of accelerators. In this paper, silica aerogel samples of different densities and thicknesses were prepared as Cherenkov radiator. The transmittance and refractive index of these samples were measured, then the absorption and scattering lengths were calculated on the basis of the obtained transmittance. The obtained results were input into Geant4 software to get the intrinsic luminescence time of the silica aerogel of different densities and thicknesses. Finally, a measurement system was constructed with the silica aerogel samples, and the rise time of this system and the silica aerogel were measured by using a picosecond electron accelerator. The results demonstrate that the rise time of the measurement system is below 180 ps and that of the silica aerogel is less than 54.32 ps. It is also proved that the silica aerogel can be used as the Cherenkov radiator for the measurement of the time spectrum of high-energy pulsed electron sources.