May 23, 2006 I’ve wasted a couple of weeks of my life tracking
down a rather odd problem with the CLEO detector, and I feel a
certain need to offload. So here follows a rather detailed
discussion of the CLEO tracking system — actually, drift
chambers in general, so if you’ve ever wondered how exactly we
follow all the particles that we create in collisions, here you
are. Say you have a particle whose path you wish to trace. You
can’t really look directly at it; you’d need very intense light,
which would disrupt the particle’s path, and at any rate isn’t
easy to make. We instead put instrumented material in front of
the particle. The aim is to use the interactions of the particle
with the material to figure out where it was, while having those
interactions be so gentle that the particle isn’t greatly
affected (usually by using some sort of amplification of a weak
signal). This is the principle behind detectors all the way from
the cloud and bubble chambers of yesteryear to the silicon (and
diamond?) detectors