Measuring beam equilibrium orbit in the VEPP-4 electron-positron storage ring

Principles of design and results of operation of a system for measuring the equlibrium orbit of the VEPP-4 beam are described. Orbit measurements are performed along the radius and vertical direction in 52 sections of the storage vacuum chamber. The beam signal spectrum width constitutes 1-2 GHz. The antonomic unit of the system is the ATsP-ORBITA unit coupled with a computer. The system comprises 8 units. One unit operates with 8 pickup stations which include pickup electrodes, filters and matching electronics. The unit alternately interrogates pickup stations: and the results are memorized by the buffer memory. On operator command the information passes in the computer which calculates the orbit. The range of beam currents during operation of the system constitutes 0.025-2 mA. At a number of particles on the orbit equal to 4x109(500 μA) the measurement mean-square error constitutes 0.15 mm