Low-noise preamplifiers/amplifiers for the time projection chamber

The special problems associated with the Time Projection Chamber resulted in the development of a new preamplifier/amplifier system which is discussed. The need for 16,000 channels of low noise electronics imposed serious contraints on the cost, size, and power consumption of the circuits. Also the preamplifiers are designed to work inside the detector chamber. This chamber operates at 10 atmosphere pressure and is sensitive both to the presence of magnetic mateials that distort the drift field, and to the effects of gas contamination. These problems resulted in the use of new components and fabrication techniques. The large number of units involved requires automatic testing as discussed in the paper.