GSI - BEA Wiki

After first testing with a simple CCD, a custom designed Proxitronic image intensified camera system #18804 was used for further investigation of OTR. The system is specified as follows:

• Bialkali photocathode (200 - 600 nm)
• V-stack double Multichannelplate (diam. 25mm)
• P46 Phosphor (decay 90%-10% in 300ns)
• Relay-Optic coupling (β 0.6)
• AVT Marlin CCD, monochrome, vga resolution

This setup enables single photon counting and fast triggering. A timing window of 100 ns could be used even for low currents, still achieving reasonable signal. The following was investigated:

• Shifted 50µs time-window to measure the change of OTR signal before/ during/ after the beam pulse » thermal afterglow could be for sure excluded !
• OTR signal comparison for polished stainless steel and for aluminium foil (10µm Al on Kapton)
• Current variation between 0,2µA and 10µA (1,4 E+07 - 7 E+08 ppp)
• OTR signal for different thicknesses of stripping foils (carbon: 370 µg/cm² ; 571 µg/cm² ; 563 µg/cm²)

First of all the data was analysed to see roughly the dependency of the light yield to the ion charge state.