A flexible, low cost, high performance ampliflier design for control of an electron accelerator used in an ultraviolet photoelectron spectrometer

Techniques are developed for the design of an amplifier which must service a portion of an ultraviolet photoelectron spectrometer. The amplifier is required to drive a voltage ramp from a precision (l6 bit) digital-to-analog converter onto a metal plate in a vacuum chamber. An additional grounded metal plate, together with the plate driven by the amplifier, forms an electron acceleration chamber. The chamber is intended for use with an electron energy analyzer to perform high resolution ultraviolet photoelectron spectroscopy studies. Electron kinetic energy levels of up to 40.8 eV are processed by the chamber.

Some of the requirements for the amplifier include a 50 volt (-10 to +40.8) output dynamic range, 2.5 ppm/°C maximum gain drift, 100 µV/°C maximum output offset drift, 25 ppm maximum nonlinearity, 1 mV rms maximum broadband output noise, and a minimum gain of 4 v/v. Use of the amplifier as part of a commercially available electronics package, produced in volume, places limitations on the cost and parts count of the amplifier. Ease of manufacture and maintenance must also be considered.

Several different operational amplifier designs for the driver amplifier are discussed. A particular dual op amp design has been built. Test procedures appropriate for the application are described and test results are included. Relevance of the techniques developed for the dual op amp design is claimed for other applications requiring computer control of precise high voltage signals.