Design of a Low Noise, Wide Dynamic Range and Small Dimension Front-end Circuit

Key words: 
• low noise /
• wide dynamic range /
• small dimension /
• front-end circuit

Abstract: A small dimension front-end circuit with low noise and wide output dynamic range is introduced in this paper. The front-end circuit is made up of a charge sensitive preamplifier, a shaping circuit and a single channel pulse height analyzer. The equivalent input noise is under 1.5 keV. The output integral nonlinearity is less than 0.11% within the dynamic range of 011 V. And the circuit can be suitable for different conditions by different modules. The resolution was about 0.12% with the charge sensitive preamplifier and the main amplifier. The energy resolution of 0.82% was achieved for 5.157 MeV -rays from a 239Pu source with the charge sensitive preamplifier, the main amplifier and anion-injection silicon detector designed by the Institute of Modern Physics(IMP). An energy resolution of 7.9% was achieved for 1.332 MeV rays from a stationary 60Co source with the main amplifier, the single channel pulse height analyzer and a CsI scintillator detector designed by the IMP. The front-end circuit has the features of wide output dynamic range, simple structure, high level of integration,small dimensions, low noise, fast rise time of the output pulse and excellent stability. The front-end circuit can be applied to signal processing of semiconductor detectors, photomultiplier tubes and electrons multiplier. And the front-end circuit had been applied to a prototype of the portable rapid measuring instrument designed by IMP for measuring Uranium, Thorium and Potassium in the salt lake brine with good
test result.