ORBIT CORRECTION IN A NON-SCALING FFAG
EMMA the Electron Model of Many Applications is to be built at the STFC Daresbury Laboratory in the UK and will be the first non-scaling FFAG ever constructed. The purpose of EMMA is to study beam dynamics in such an accelerator. The EMMA orbit correction scheme must deal with two characteristics of a non-scaling FFAG: i.e. the lack of a well defined reference orbit and the variation with momentum of the phase advance. In this study we present a novel orbit correction scheme that avoids the former problem by instead aiming to maximise both the symmetry of the orbit and the physical aperture of the beam. The latter problem is dealt with by optimising the corrector strengths over the energy range.
DIAGNOSTIC SYSTEM COMMISSIONING OF THE EMMA NS-FFAG FACILITY AT DARESBURY LABORATORY FRONT-END
We present a single-shot/turn-by-turn BPM system for the world’s first Non-Scaling FFAG Accelerator ‘EMMA’. To satisfy the requirement of high rate measurement, the BPM system utilizes a front-end conversion of button pickup signals into compact flat-topenvelope 700MHz bursts. This allows also applying timedomain multiplexing into a single channel. In the BPM, both synchronous detector and ADC clocks are directly manufactured from the beam signal. The system architecture is described; BPM features are discussed; initial results of beam tests done on the ALICE injector have been given. mi a low-pass filter are sampled one-byon of the sampling noise generated by A ltage noise which is produced by the jitter of each
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.