A fast low noise charge preamplifier for position sensitive detectors

We present the design and the results of the evaluation of a fast, low noise, charge preamplifier. This device uses commercial circuits; the advantages over classical circuits based on transistors are presented. These include short development time, high reliability and reproducibility, and easy maintenance. The amplifier has been tested with a position sensitive multiwire proportional counter with a readout system based on delay lines. With an input impedance of 50 Ω, we have obtained a signal to noise ratio better than 40 dB, a gain of 0.42 μV per electron, a pulse rise time of 9.4 ns, and a total pulse duration lower than 120 ns. These values allow detector data acquisition rates in excess of 1 MHz, and a spatial resolution better than 300 μm.