481 MeV muon neutrino (MC) produces 394 MeV muon which later decays at rest into 52 MeV electron. The ring fit to the muon is outlined. Fuzzy electron ring is seen in yellow-green in lower right corner. This is perspective projection with 110 degrees opening angle, looking from a corner of the Super-Kamiokande detector (not from the event vertex). Option -show_non_hit was used to show all PMTs. Color corresponds to time PMT was hit by Cerenkov photon from the ring. Color scale is time from 830 to 1816 ns with 15.9 ns step. The time window was widened from default to clearly show the muon decay electron in different color. In the charge weighted time histogram to the right two peaks are clearly seen, one from the muon, and second one from the delayed electron from the muon decay. Size of PMT corresponds to amount of light seen by the PMT. PMTs are drawn as a flat squares even though in reality they look more like huge flattened golden light bulbs.
Special huge (high resolution)
version for print, with colors optimized for CYMK
(less blue and purple, more red and orange, as requested by publisher).
This image appeared in
May-June 1999 issue of
American Scientist
and in
November 2006 issue of La Recherche
(in French).
1063 MeV neutrino (MC) strikes free proton at rest and produces 1032 MeV muon. Color scale is time from 987 to 1080 ns with 2.3 ns step. PMTs close to the vertex were hit earlier than PMTs farther away.
Special huge version for print, with colors optimized for CYMK
Same event but in cylindrical projection - a 4*pi view (full solid angle, 360 degrees around). Un-hit PMTs are hidden but detector grid is shown. The observer is positioned in the event vertex.
The three images below were created for my talk at ACS meeting at Anaheim on 1999-03-22. They have color scale modified for CYMK printing on transparencies.
600 MeV electron (MC). Electron ring is much more fuzzy than muon ring. Electron produces shower of gammas, electrons and positrons. Gammas don't produce Cerenkov light. Electrons and positrons do. In the shower each of them flies at a little bit different angle and each of them makes its own weak Cerenkov ring. All those rings added together produce the observed fuzzy ring. This difference in sharpness of muon and electron rings is used to identify muons and electrons in Super-Kamiokande. The color time scale spans 87 ns.
Multiple ring event.
This event was one of the close candidates for proton decay into
positron and pi zero. Pi zero would decay immediately into two gammas
which make overlapping fuzzy rings.
Positron and pi zero would fly in opposite directions.
This is a real event (not Monte Carlo) recorded on 1997-09-24 12:02:48.
It was found by Brett Viren, but it did not pass analysis cuts.
Time color scale spans 80 ns.
Through-going muon.
The muon entered through the flat circular part of the detector
near the bottom of the image where purple earliest PMT hits can be seen.
It exited through the cylindrical side wall in the middle of the image.
This is a real event (not Monte Carlo) recorded on 1996-05-30 17:12:56.
Time color scale spans 262 ns.
Option "-tube_sizing log" was used to cover wide dynamic range of PMT charge.
