Speaker
Description
Optical beam diagnostics based on transition radiation (TR) is widely used to measure both transverse and longitudinal bunch sizes. However, in installations based on modern acceleration techniques (laser-plasma, etc.), the intensity of the resulting beam may be insufficient for TR diagnostics. The application of alternative, more intense radiation mechanisms will improve the accuracy of optical diagnostic methods, particularly in low-intensity beam diagnostics.
This report presents the results of detailed studies comparing the characteristics of Cherenkov radiation (ChR) with traditional TR in the context of beam diagnostics.
The experiment was carried out using an electron beam from the LINAC-200 accelerator with an energy of 18 MeV. Radiation detection was performed at an angle of 90 degrees relative to the electron beam using the TAMRON lens with a focal length of 18–400 mm and a CCD camera. The TR and ChR targets used were an aluminized silicon wafer and a corundum plate (0.5 mm thickness). When focusing “on the target”, the dimensions of the “light footprint” of a collimated electron beam with a diameter of 5 mm on both targets were measured.
The shape of both footprints was approximated by a Gaussian in the vertical and horizontal directions with parameters σv=σh=1.97 mm (TR target) and σv=5.02 mm and σh=2.16 mm (ChR radiator). The registered intensity of TR and ChR was determined after subtracting the “background” contribution. As a result, the ratio between the photon yield of TR and ChR was 1:9.6. This result agrees reasonably with theoretical calculations.
