Our outreach efforts are based on the fact that so few students--not
just high school students but even most
physics majors--are rarely exposed to the existence
of cosmic rays.
High School Outreach
We plan on building a large
cosmic ray air shower array by distrubuting detectors
across Los Angeles
high schools. This will build on a UCLA
Walter Gekelman, Bill Layton
and others have organized high schools to
take simulataneous seismometer data
using synchronized clocks and the internet.
The project will be done in cooperation with
More information will be added to this page as the project develops.
Another project is the refurbishment of UCLA/180F, the undergraduate
"Cosmic Ray Lab". The students work on one lab for the entire quarter.
Briefly, the experiments are:
Experiment 1: Muon lifetime and magnetic moment
The students use scintillator paddles above and
below a copper target to detect stopping muons. The
proper logic signals start a TDC. The mu- are quickly captured so
that the target is left with mu+.
They cable the system so that the positron from the decay of mu+
stops the TDC. The students directly measure the muon lifetime and
the ~80\% polarization
of cosmic mu+ (due to parity violation at their production).
Then they turn on a perpendicular magnetic field so that the muons precess.
The ratio of up vs. down decays shows an oscillation as a function of time,
which gives the muon's magnetic moment.
Experiment 2: Muon+ lifetime and muon- capture rate
In this experiment,
the students also cable the trigger to start a TDC when a muon stops in the
target. In this case, they subsequently
detect either the neutron from mu- capture
or the positron from mu+ decay based on the amplitude of a pulse in
liquid scintillator. They measure the dramatic dependence of the capture
rate of mu- on the Z of the material.
Experiment 3: Spark chambers and multiple scattering
In this experiment, the students position absorbers and cable an appropriate
trigger to select a momentum bite of cosmic muons in a target. The
trigger sets high voltage on spark chambers so that they observe the
muon's track. A video camera takes a picture, and offline software
finds a track. By changing the thickness of the target or
momentum selector, the students measure that multiple scattering goes as
the square root of the target thickness and inversely with the momentum.
We will upgrade the laboratory
with new computers, higher resolution TDCs,
working NIM modules, new cable-delay
boxes, new cables/adaptors/connectors, new furniture, portable
digital voltmeters, digital oscilloscopes and a digital camera for the
spark chamber lab.