Automatic Position Control in the A2-Beamline Patrik Ott Institut für Kernphysik Johannes-Gutenberg Universität Mainz

Abstract Main Principles Realization at MAMI –XY – Monitors –Correction Magnets Integration in MAMI control-system Results

A2-Beamline TM 110 Scanners already installed

Main Principles

Asymptotic Stability a 0, b 0 : starting positions at the XY-Monitors as, b s : desired positions at the XY-Monitors a n, b n : positions at the XY-Monitors after the n th step dx k /dI l : the derivate of the position in the k th XY-Monitor with respect to the current in the l th magnet. After the first step: After the second step: constant ckck

Choice of Controllers Horizontal Pair of Controllers c WEDL06 – DIPL07KO0.33 WEDL06 – WEDL ( 0.11 ± 0,02 ) DIPL07KO – WEDL Vertical Pair of Controllersc WEDL06 – WEDV WEDL06 – DIPL WEDV07 – DIPL ( Rüdiger Fritz, 1998 )

A2-Beamline TM 110 Scanners already installed possible horizontal Controllers possible vertical Controllers

Cavity readout Preamplifier with 44dB Need to decrease frequency to 100 kHz Due to the low voltage, a Lock-In Amplifier is used for measurement. Up to now a relay toggles horizontal and vertical signals.

Integration in MAMI control-system The aim is to design an interface that is easy to use by the MAMI-operators. Problems with the Lock-In Amplifiers: correct phase adjustment integration time at least 2 sec. unpredictable behaviour in case of overload

Present Status All components are installed Horizontal parameters have been measured Service-routine for MAMI control system is running

Next Steps Measure vertical parameters ( 3 h beamtime ) Determination of the minimum beam current ( 2 h beamtime ) Integration in the Crystal Ball data acquisition