A twin amplifier for drift chambers readout

A twin amplifier for drift chambers having a doublet of anode wires with the aim of solving the left-right ambiguity has been developed. Chambers of this type, working with a HeiC4H10 mixture, will be used by the FINUDA spectrometer at DAΦNE. This dedicated amplifier, which subtracts the induced positive signal from the direct negative one, reduces the noise on the electronic chain and cancels the common noise from external sources. Results of laboratory and beam tests, showing that this amplifier can improve the signal to noise ratio, are presented.