A linear gate and transmitter for improving localization using the charge division method

We developed an electronic system which, used with drift chambers, allows to perform a precise charge division measurement of the longitudinal coordinate, even if the sense wire is held at high voltage and a decoupling capacitor is needed. The idea is to create a temporal gate at the arrival of the signal and transmit to the ADC only this part of the signal. The gate remains open for a short period (120 ns), corresponding to the duration of the anode pulse and delivers, at its output, a pulse of amplitude linearly dependent from the input value. In this way the systematic error is better than 1% of the wire length. It introduces a considerable improvement in comparison with previously used software corrections, mainly from the linearity and simplicity point of view.