(A) Computer modelling of bunch-by-bunch feedback for the SLAC B-factory design*

bunches circulating in each ring, will require a feedback system to avoid coupled-bunch instabilities. A computer model of the storage ring, including the RF system, wake fields, synchrotron radiation loss, and the bunch-bybunch feedback system is presented. The feedback system model represents the performance of a fast phase detector front end (including system noise and imperfections), a digital filter used to generate a correction voltage, and a power amplifier and beam kicker system. The combined ring-feedback system model is used to study the feedback system performance required to sup press instabilities and to quantify the dynamics of the system. Results are presented which show the time development of coupled bunch instabilities and the damping action of the feedback system. I

The polarized electron gun for the SLC

A new polarized electron gun for use on the SLC at SLAC has been built and tested. It is a diode gun with a laser driven GaAs photocathode. It is designed to provide short (2ns) pulses of 10 A at 160 kV at 120 Hz. The design features of the gun and results from a testing program on a new and dedicated beam line are presented. Early results from operation on the SLC will also be shown

(A/I) PROMPT BUNCH BY BUNCH SYNCHROTRON OSCILLATION DETECTION VIA A FAST PHASE MEASUREMENT*

An electronic system is presented which detects synchrotron oscillations of individual bunches with 4 ns separation. The system design and performance are motivated by the requirements of the proposed B Factory facility at SLAC. A comb generator is used to produce an eight cycle coherent tone burst at 3 GHz from each bunch. The phase of the coherent burst is compared with a master oscillator in a double balanced mixer. The detected mixer output is digitized at a 250 MHz rate, yielding a unique phase measurement for each bunch. Laboratory results are presented which show that the prototype is capable of measuring individual bunch phases with better than 0.5 degree resolution at the 476 MHz RF frequency. A system design for damping longitudinal oscillations of 1658 bunches using this detector is also shown

Computer modelling of bunch-by-bunch feedback for the SLAC B-factory design

The SLAC B-factory design, with over 1600 high current bunches circulating in each ring, will require a feedback system to avoid coupled-bunch instabilities. A computer model of the storage ring, including the RF system, wave fields, synchrotron radiation loss, and the bunch-by-bunch feedback system is presented. The feedback system model represents the performance of a fast phase detector front end (including system noise and imperfections), a digital filter used to generate a correction voltage, and a power amplifier and beam kicker system. The combined ring-feedback system model is used to study the feedback system performance required to suppress instabilities and to quantify the dynamics of the system. Results are presented which show the time development of coupled bunch instabilities and the damping action of the feedback system. 3 refs., 5 figs., 2 tabs

Prompt bunch by bunch synchrotron oscillation detection via a fast phase measurement

An electronic system is presented which detects synchrotron oscillations of individual bunches with 4 ns separation. The system design and performance are motivated by the requirements of the proposed B factory facility at SLAC. Laboratory results are presented which show that the prototype is capable of measuring individual bunch phases with better than 0.5 degree resolution at the 476 MHz RF frequency. 13 refs., 6 figs., 1 tab

(A) POLARIZED SOURCE PERFORMANCE IN 1992 FOR SLC-SLD*

In its initial operation, the SLC Polarized Electron Source successfully met the SLC goals for 1992 for intensity and efficiency. However, the stability of the beam at the source was marginal, and the polarization was only-28%. The SLC goal to provide> 10,000 Z events for the SLD from polarized electrons was met. 1