The Carnegie Mellon group is responsible for the front-end
electronics for the anode wires of the endcap muon system. This
involves over 160,000 channels of electronics. We are building
custom-designed preamplifier/shaper/discriminator integrated circuits
for this purpose. The block diagram of the electronics is shown
here.
The requirements of the electronics
are very low noise, allowing a threshold of about 10-20 fC on the
chamber and very good time resolution (time slewing of less than 3 ns
for signals from 50 to 1000 fC). Using the 6 layers of a chamber, we
want to be able to identify the correct beam crossing for a muon with
greater than 92% efficiency. By time-ordering the up to 6
signals from a chamber and using, for example, the second
earliest time as an
indication of which beam crossing the muon came from, we have obtained
time resolutions of about 5-6 ns rms. This time resolution results in a
beam crossing efficiency easily above the 92% requirement.
The preamp chips each contain 16 channels of input. The chips sit
on specially designed boards, which plug directly into the side of the
chamber and contain one chip per board (
Boards on CSC layout
).
The rest of this web site contains
detailed information about the design and present status of the chips
and boards, the calibration of the electronics, and results of
prototypes from cosmic ray and test beam runs.