Performance of the TRISTAN main ring magnet

The main-ring magnet system of the TRISTAN accelerator has a circumference of 3 km and is composed of four arcs of 377 m average radius and four long straight sections of 194 m length. Each arc contains 68 dipole magnets and 76 normal quadrupoles; each long straight section contains 22 normal quadrupoles and 4 insertion quadrupoles. The sextupole magnet system consists of 240 laminated magnets with two different lengths. The integrated radial field profiles of the dipole were measured by a 6.5 m long flip coil at several excitation levels. The voltage induced in the coil was integrated and measured by a digital voltmeter. The excitation curve, which is a relation between magnetic strength and current, was measured by using a 6.5-m search coil with 70.053-mm width at 17 excitation currents under pulsed excitation. For the quadrupoles, the integrated transverse-field profiles and the excitation curves were measured using conventional long twin coils under pulse operation of a power supply. For the sextupole and the steering dipoles, the field qualities were measured statically using a rotating coil and a spectrum analyzer. Performance results for the dipoles, quadrupoles and sextupoles are presented and discussed.