A +/-700 volt,+/-350 amp switchmode power supply has been developed for Fermilab Main Injector Sextupole Correction System. The four quadrant operation is accomplished by using four IGBTs in an H-bridge configuration with a switching frequency of 10 KHz. Current regulation bandwidth of 300 Hz is achieved with stability better than 250 ppm of rated current by using a high precision current transducer. The H-bridge outputs are filtered resulting in a maximum output voltage ripple of 2.5 volts peak to peak. The power supply has power conversion efficiency better than 80% and works at near unity power factor throughout its operation. The critical considerations involved in this power supply are low inductance bus plate and snubber design, selection and thermal management of IGBTs, IGBT gate drive, PWM output filtering, and fiber optic controls. The paper will discuss the design and performance of the power supply.

The Fermilab Main Injector (MI) will accelerate (decelerate) protons and anti-protons from 8.9 GeV/c to 150 GeV/c (150 GeV/c to 8.9 GeV/c). To achieve high intensity stable beam in the MI throughout the acceleration or deceleration mode, two families of chromaticity compensation sextupole magnets are planned. The operating schemes for the chromaticity compensation systems will be different for the two modes because of the hysteresis of the sextupole magnets and the changed sign of the sextupole field component from beam tube eddy currents in the dipoles. Hence we have carried out detailed magnetic field measurements on some sextupole magnets. Here we present the results of the measurements and their implications on the acceleration and the deceleration cycles of the MI.

The power supply design of the γ t-jump system in FNAL Main Injector uses a resonant circuit[1]. A critical design parameter is the ac losses of the beam tube in a pulsed quadrupole. This paper gives an analysis to this problem. An equivalent circuit model based on the impedance measurement was established. The measured and calculated losses are in agreement. Another effect of the eddy current is the distortion of the magnetic field inside the beam tube. A Morgan coil was used for field measurements up to 10 KHz. These results are presented in this paper.

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