| The CDF detector is undergoing a major upgrade from its Run I (1992-1995)
configuration to prepare it for the next round of data taking (Run II),
scheduled to begin in late 2000. The result will be
a detector which can handle the significant increase in data rate made
possible by accelerator improvements. We expect a factor
of 20 times more data from the next running period than from the previous
run. This, along with fundamental improvements in our ability to
select interesting events from the background of run-of-the-mill inelastic
collisions in real time (within 20 microseconds), will result in an effective
increase of factors of 100 to 1000 in the numbers of many interesting types
of events. This enormous increase in data presents an exceptional
opportunity for new discoveries over the next few years. Details
regarding the detector upgrade can be found in the CDF
II Technical Design Report.
The upgrade to the detector is an important part of our group's effort,
and we have extensive responsibilities in this project. We are designing
and fabricating key elements of the trigger electronics
using state-of-the-art computer-aided design tools from Mentor Graphics,
Cadence and Xilinx, and making extensive use of
programmable
logic chips. The trigger system is responsible for making decisions,
in tens of microseconds, as to whether a particular event might be likely
to be interesting for later analysis. Due to the enormous number
of uninteresting background events at a proton-antiproton collider, a system
which effectively rejects these background events while maintaining most
of those we wish to study is a critical component of the experiment.
A second project we have undertaken is the upgrade to the precision
tracking chamber (SVX II) which allows us to determine
the trajectories of charged particles produced in a p-pbar collision to
within approximately 10 microns. This ability allows us to search
for events which have a long-lived (1E-12 seconds is long for us) particle,
by locating the decay products of this particle and finding that they appear
to originate at a location separate from other particles in the event.
It is this signature which led to the discovery of the top quark, and makes
all the b-sector measurements possible. It is also true that many
exotic particles (supersymmetric particles, leptoquarks, Higgs, etc)
have decay products which include a long-lived particle. Precision
tracking is a powerful tool for searching for these new particles.
The detector itself is made up of p-type silicon wafers with n-type implants,
arranged in strips approximately 50 microns apart. Charged particles
traversing the wafer create electron-hole pairs in the semiconductor, which
are collected at the implants, identifying the location of the charged
particle. The new detector has 5 layers of these detectors, each
approximately 1 m long, with a total of 750,000 strips, each with its own
amplifier and storage pipeline. Our group is involved in the electronics
system associated with reading out and recording the data from the detector.
This system has a highly parallel architecture using high-speed optical
transmitters and receivers to achieve the throughput needed, with hundreds
of components which must be made to work together smoothly.
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