5 Solid State Detectors
159
Fig. 5.17 Double-correlated sampling of the output of a charge-sensitive amplifier (CSA1) with
the help of a coupling capacitor C s and a second CSA2
changes the output of CSA1 by U 1 = Q s /C f1 and the output voltage by U out =
Q s (C s /(C f1 C f2 )); and (4) opening of switch S c at time t 4 inhibits further change
of the output voltage. The difference of the output voltage of CSA1 (amplified by
C f2 /C s ) between times t 2 and t 4 remains present at the output of the circuit.
Double correlated sampling suppresses the reset noise due to operating switch
S 1 and also suppresses low frequency noise but enhances the noise at higher
frequencies. As a result white noise is not suppressed. This has to be done
by limiting the frequency range of the amplifier. More sophisticated schemes
of switched capacitor filtering, taking several samples (sometimes with different
weights), have also been implemented.
5.7.3 Integrated Circuits for Strip Detectors
The development of integrated detector readout electronics was initiated by the
simultaneous requirements of high density, low power and low noise for use with
silicon strip detectors in the tight space environment of elementary particle physics
159
Fig. 5.17 Double-correlated sampling of the output of a charge-sensitive amplifier (CSA1) with
the help of a coupling capacitor C s and a second CSA2
changes the output of CSA1 by U 1 = Q s /C f1 and the output voltage by U out =
Q s (C s /(C f1 C f2 )); and (4) opening of switch S c at time t 4 inhibits further change
of the output voltage. The difference of the output voltage of CSA1 (amplified by
C f2 /C s ) between times t 2 and t 4 remains present at the output of the circuit.
Double correlated sampling suppresses the reset noise due to operating switch
S 1 and also suppresses low frequency noise but enhances the noise at higher
frequencies. As a result white noise is not suppressed. This has to be done
by limiting the frequency range of the amplifier. More sophisticated schemes
of switched capacitor filtering, taking several samples (sometimes with different
weights), have also been implemented.
5.7.3 Integrated Circuits for Strip Detectors
The development of integrated detector readout electronics was initiated by the
simultaneous requirements of high density, low power and low noise for use with
silicon strip detectors in the tight space environment of elementary particle physics