Low mass, high density packaging and signal transmission for high rate colliders

The Front End electronics system designed for the Solenoidal Detector Collaboration (SDC) Barrel Tracker demonstrates some aggressive methods for detecting and routing out 140 thousand channels of proportional straw drift tube signals. The electronics must detect charge pulses as low as 2 fC and determine their time of arrival to within 1 ns. Aggressive PC board substrate and interconnect designs, along with a custom amplifier, shaper, discriminator IC, contributed to a successful beam test at BNL in July of 1993. The 400 channel, full density system functioned well at a 3 fC threshold level despite the noisy AGS environment, and without any shielding of the 4 meter long straw chambers. Since then we have designed flat Kapton cables, which can be manufactured in 16 foot lengths and connected together with standard fine pitched connectors. These cables demonstrated that sub-nanosecond timing for up to 7 meters was possible. Work is continuing to apply the crosstalk and noise abatement lessons learned at BNL to integrating digital readout chips directly on or near the same PC board substrate housing sensitive analog amplifiers. Part of this effort is directed to design/fabrication of differential, low level (/spl sim//spl plusmn/150 mV), current mode CMOS drivers and receivers.<>