Interesting SNO Events
Calibration: We use gamma rays from a Nitrogen-16 source to
create Cerenkov light for calibration purposes. This image shows one such event. The
similarity to the solar-neutrino signals shown above indicates just how
useful a calibration tool this is.
Double-Ring Event: This is arguably our prettiest event to date.
In this event
a muon entered the SNO detector and exited through the pink region at the
top of the detector. (The pink indicates these photomultiplier tubes
detected a great deal of light.) This is typical of muons. What is not so
typical, is that the muon interacting in the detector produced a secondary
electron. This electron produced the large ring just below the exit point
of the muon.
contained muon: Some of the muons detected in SNO are created by
interaction of an atmospheric neutrino in the heavy water. These muons
often decay in the detector rather than travel right through it. This muon is
an example. The electron which resulted from the decay of the muon also
generated an event
in SNO. From the time stamp on the two images. You can see that the events
both occurred at 6:19 AM and 22 seconds. Looking at the decimal places
after the seconds in the time, we see the electron event occurred 0.9
microseconds after the muon event.
The event pictures above are
taken from screen captures of XSNOED
(the X-windows SNO Event Display).