Studies of stochastic momentum cooling are being conducted on the FNAL 200-MeV Storage Ring. The specific goal of the activity is to establish confidence in the theory and simulation methods used to describe the cooling process, and to develop techniques and devices suitable for use in the antiproton accumulation scheme now planned for construction at FNAL. A summary of the activity, including hardware design, results of experiments, comparison with theory, and implications for the antiproton accumulator are presented.

The Rapid Cycling Synchrotron (RCS) accelerator of the Intense Pulsed Neutron Source-I (IPNS-I) at Argonne National Laboratory utilizes a fast kicker magnet to provide single-turn extraction for a 500 MeV proton beam at a 30 Hz rate. The single-turn, 0.89 m long ferrite magnet is broken up into two identical cells with four individual windings. Each winding requires a 4863 A magnetizing current into a 7.0 Ω load with a rise time of less than 100 ns and a flattop of about 140 ns. Pulse forming network (PFN) charging and switching techniques along with the components used will be described.

Two ferrite loaded picture frame magnets with a kick of up to 15 mrad each are used to extract 500 MeV protons from the IPNS-I accelerator to the neutron source target at the Argonne National Laboratory. The magnet aperture is 10 cm wide by 5 cm high and the length is 60 cm. The single bunch extraction requires a magnetic field rise time (0 to 100%) of 90 ns and a flattop of 100 ns. The magnets re...

Modifications made on the ZGS to allow the acceleration of polarized deuterons and the operational experiences with the first production run with this beam are described.

A number of high energy physics experiments are based on a random distribution of particles entering the experimental appa. ratus. Unfortunately, the extra. cted beam from a proton synchrotron will display a bunching due to the RF cavity. However, this bunching can be reduced or destroyed by various techniques; such as, by introducing noise into the RF cavity during extraction, or by lengthening the energy loss target. Therefore, in order to measure the effectiveness of these various techniques, a monitoring system is needed to detect the amount of RF structure present in the extracted beam. The design of the RF structure monitor used at the Zero Gradient Synchrotron (ZGS) will now be described. Further, the results obtained from using this system will be discussed.

We have, at the Zero Gradient Synchrotron (ZGS), a beam viewer which displays in near real time the brightness, width, and position of the beam. This consists basically of a calibrated phosphorescent screen which nondestructively collects ions generated by the circulating beam. A closed circuit TV system transports the signal to the Main Control Room. Circuits were developed which derive analog voltages representative of the beam width and position from the synchronization and video signals. The brightness vs. horizontal position linearity was improved by vidicon model change and a simple shading circuit. A calibrator which simulates a beam was built into the system and is invaluable for initial setup and linearity tests.

Small, air-filled, ion chambers have been constructed to serve as localized beam spill monitors. They are mounted at the downstream end of each straight section of the ring and are useful for locating beam obstructions and for finding spills due to abnormal machine adjustment. The chamber is made up of thin aluminum sheets with mylar insulation and is enclosed in a lucite box. No preamplifier is used, but the signals are transported to the Main Control Room (MCR) via RG-22/U shielded pair to maintain good SNR. A central 300 V power supply provides ion collection potential for all eight chambers. The signals are processed for individual and multiplexed monitoring.

To establish a meaningful history of the electrical condition of our main magnet coils, various instruments and techniques were developed for a diagnostic program.

The titanium vacuum chambers installed in the ZGS this past summer were equipped with PFW's. In this paper, the operation and monitoring of the windings used to flatten the guide field in the ZGS will be described. The physical and electrical characteristics of the system will be discussed along with a computer program which calculates the magnetic field shape in the vacuum chamber as a function of PFW current and other machine parameters.

Two main coil failures in a one-year period initiated a review of on-line protective circuitry. Two existing circuits, which would limit damage, were made more reliable. Four new circuits were added to monitor coil condition and protect against voltage transients.

Solid state high frequency limiter amplifiers and fast rise time voltage comparators for pulse shaping make zero crossing time a meaningful phase reference. A circuit based on these principles was developed and is in use in the beam phase feedback loop of the ZGS. It has excellent linearity for voltage out vs delay for up to 50° with a phase error of < 8° for the following input condition: input voltage amplitude from 0.1 - 2.0 V and beam bunch rate from 4.4 - 14.0 MHz. A detector is included to insure a zero output reference when there is no beam or when beam levels are below the phase-lock threshold.