Wire Scanner Motion Control Card

Scientists require a certain beam quality produced by the accelerator rings at CERN. The discovery potential of LHC is given by the reachable luminosity at its interaction points. The luminosity is maximized by minimizing the beam size. Therefore an accurate beam size measurement is required for optimizing the luminosity. The wire scanner performs very accurate profile measurements, but as it can not be used at full intensity in the LHC ring, it is used for calibrating other profile monitors. As the current wire scanner system, which is used in the present CERN accelerators, has not been made for the required specification of the LHC, a new design of a wire scanner motion control card is part of the LHC wire scanner project. The main functions of this card are to control the wire scanner motion and to acquire the position of the wire. In case of further upgrades at a later stage, it is required to allow an easy update of the firmware, hence the programmable features of FPGAs will be used for this purpose. The FPGAs will act as the control unit of the system. As the LHC has two separate vacuum chambers for the two counter rotating proton-beams, a wire scanner is needed for both the horizontal and vertical beam profile measurement. One motion control card is expected to control two wire scanners. The position of the wires must be acquired within a certain accuracy to meet the specification set for the LHC. In order to obtain the correct beam profile, the position acquisition must be well synchronized with the acquisition of the beam density. The values have to be stored in a memory, which is readable through the VME64x-bus.