Equivalent noise charge for different impedance-matching schemes of the drift straw-tube and the amplifier

Impedance matching of the drift straw-tube and the amplifier influences the signal-to-noise ratio, which, in turn, determines the coordinate resolution of the detector, the minimal threshold, and the minimal gas amplification necessary for efficient signal registration by the detector. Five impedance-matching schemes for the straw-tube detector with a length of 2.5 m are studied. It is shown that ENC = 4000−5000 electrons for C det = 20−30 pF, which is good from the practical point of view, is achieved using the simple resistor connected in series to amplifier at the open far-end of the straw-tube.