Efficacy testing of shielding materials for XFEL using the radiation fields produced at FLASH

The European X-Ray Free Electron Laser (XFEL), a grand international scientific endeavour to produce extremely brilliant (~ 10 photons/s/mm/mrad), ultra short pulsed (~ 100 fs) coherent X-rays of wavelengths down to 0.1 nm is now under construction at DESY (Deutsches Elektronen-Synchrotron) laboratory. The XFEL facility, which measures a total length of 3.3 km will be driven by a 1.7 km long, 20 GeV electron linac made of high-purity superconducting niobium cavities developed at DESY under TESLA (Tera Electron-Volt Superconducting Linear Accelerator) technology collaboration. The electron linac section of the XFEL will be housed in a 5 m diameter underground concrete tunnel. Furthermore, all electronic equipments vital to machine safety, operation and control system of the linac, as well as the klystrons and power supplies will also be installed in the tunnel. Intense field of parasitic (ionising) radiations will be generated during linac operation thereby causing radiation induced detrimental effects in the electronic devices. Hence, in order to guarantee a safe and flawless linac operation, it is imperative to implement suitable radiation shielding around the racks containing those electronic equipments.