Research in physics, biology, chemistry, pharmacology, material research and in other branches more and more
frequently use free electron lasers as a source of very intense, pulsed and coherent radiation spanning from optical, via
UV to X-ray EM beams. The paper presents FLASH laser, which now generates VUV radiation in the range of 10-50nm.
The role of low level radio frequency (LLRF) control system is shown in a superconductive linear accelerator. The
electron beam from accelerator is injected to the undulator, where it is "converted" to a photon beam. The used LLRF
system is based on FPGA circuits integrated directly with a number of analog RF channels. Main part of the work
describes an original authors' solution of a universal LLRF control module for superconductive, resonant cavities of
FLASH accelerator and laser. A modular construction of the module was debated. The module consists of a digital part
residing on the base platform and exchangeable analog part positioned on a number of daughter-boards. The functional
structure of the module was presented and in particular the FPGA implementation with configuration and extension
block for RF mezzanine boards. The construction and chosen technological details of the backbone PCB were presented.
The paper concludes with a number of application examples of the constructed and debugged module in the LLRF
system of FLASH accelerator and laser. There are presented exemplary results of quality assessment measurements of
the new system board.