Development of a Precision Amplifier for the Detector

A trans-resistance amplifier has been designed and tested to measure the intensity of synchrotron radiation at Pohang Light Source (PLS). The front-end stage of the amplifier was implemented using discrete circuit elements and can measure input current in the range of 1 pA to 1 μA. A microprocessor interfaces the amplifier with computer and controls the other sub-circuits for synchrotron radiation measurement. The amplifier was tested and obtained a resolution of ∼ 20 fA, a temperature drift of ∼ 0.1 pA/°C, and a signal-to-noise ratio greater than 80 dB.