Straw Tube Readout Electronics
The straw chamber readout electronics were designed by a group at Stanford for an experiment at Brookhaven (e871).
The first stage of the readout is a preamplifier and discriminator card (P/D). Each card processes the signals from 6 straws in independent and isolated channels. The P/D card connects directly to the ends of the straws and as a result the high voltage (~1650 V) must be applied through the card as well. The card output is a differential ECL logic signal with a width determined by the analog signal's time over the descriminator threshold.
After a twisted pair cable run of 48 feet, the signals are read and retransmitted by the next stage of electronics, the "redriving" board. Each redriving board receives up to 96 channels of straw signals, extends each signal to a minimum width of 30 nsec (to improve the signal's resistance to attenuation), and consolidates channels into bunches of 16 for the upcoming 141 foot run of twisted pair cable.
The signals are then received by a LeCroy 3377 TDC which is operating in common stop mode.