Quadrupole Electronics

The quadrupole electronics generate raster-scan voltage waveforms for driving the quadrupole deflection plates, which electrostatically deflect the electron beam. The quadrupole electronics also provide for magnifying and rotating the raster. The deflection waveforms can be generated over a five-decade range in operating frequency.

The quadrupole electronics consist of twro independent ramp and step generators. Each generator is responsible for ihe waveforms for one pair of quadrupole plates.

The ramp and step generator (see block diagram, Fig, 3) generates output voltages that are sums of ramps and steps. The ramp portion of the waveform is formed by an integrator composed of HI, CI. At, and Ql, The slope of the ramp is controlled by the output voltage of a digital-to-analog converter (DAC). The ramp is reset by FET Ql. The step portion of the waveform is generated by two DACs, one to control the step size, and the second, a multiplying DAC or M DAC, to control the number of steps. The ramp and step

Level

L

r

Converter

Ramp Trigger

Ramp Slope

Scale

Line Number

Of* sel

Integrator IRamp Generator)

Step Size

Line Number

Line Number

Summing Amplifier

Inverter

Fig. 3. The driver for the quadrupole deflector generates raster-scan voltages to deflect the electron beam. It consists of two of these ramp and step generators.

VvV eo wi

High-Voltage Amplifier

- Output

High-Voltage Amplifier

Digital Input

Digital Input lo*c=0-2 mA

O AC

Cascode

Cascode

O AC

0 0

Post a comment