Logic and Control Module for the Fermilab Booster Beam Damper
A logic and control module is included in the electronic system of the booster superdamper. This module produces a 9-bit digital word that controls the delay of beam bunch position information in the Fermilab booster synchrotron so that it arrives at the damping electrodes at the same time as the bunch of beam to be corrected. This delay word generator also has an output feature that only allows delay time decreases as the booster synchrotron frequency program increases monotonically. Such a feature guards against low-index incidental FM from affecting the delay computations.
The Transverse Feedback System for the CERN PS Booster
With the operational beam intensity in the PSB continuing to increase, transverse stability will soon become a limiting factor. To damp transverse instabilities, a wide band feedback system has been designed and built, and it is being installed at present. It consists of eight independent systems (four rings, two planes), based on the usual scheme (position sensor, and deflector located at an odd number of betatron quarter wavelengths). Specific features of the PSB system are: large bandwidth (> 50 MHz), limited by easily modifiable filters; continuous and automatic delay tracking (by digitally controlled delay lines) coping with the proton velocity variations (ß ¿ 0.31 to 0.84); automatic suppression of the closed-orbit induced signal, allowing considerable savings in the power rating of the output amplifiers. The paper describes the system and its characteristics.
An analytical approach to the design of electrodes in high-power, fast-transverse-flow CO2 lasers
Abstract Usually, the design of the electrodes of fast-transverse-flow CO 2 lasers relies more on experimental data than on theoretical analysis. Traditional systems sustain a stable, high-power discharge but the current distribution generates a peaked, non-uniform small-signal-gain pattern. We present a theoretical model suitable for the design of electrodes that achieves a quasi uniform gain distribution. The analysis, based on a two-temperature model and the gas-transport equations, computes the electron density that supports a flat gain pattern. Combining the desired electron density with the electron-balance equations, the model determines the required electric field. The results were used to design a new set of electrodes for a home-made fast transverse flow CO 2 laser. A stable, large volume discharge ( 4 × 8 × 90 cm 3 ) with very good uniformity was obtained. The resulting gain distribution was registered in a bi-dimensional map. The peak gain rose from 1.2 m - 1 , attained with the old electrode set, to 1.6 m - 1 with the new one and the gain showed a homogeneous profile.