60 likes | 156 Views
IceTop – string 21 coincidences. Dmitry Chirkin, LBNL. Presented by Tom McCauley. Coincidence timing test. leading edge time t hit of string 21 DOMs 1, 26, 56 (with t IceTop = 0 ). Depth (km / m s). 0 / 0. 1.45 / 4.8. DOM 1. 1.88 / 6.3. DOM 26. 2.39 / 7.9. DOM 56. 39. 30. 29. 21.
E N D
IceTop – string 21 coincidences Dmitry Chirkin, LBNL Presented by Tom McCauley
Coincidence timing test leading edge time thit of string 21 DOMs 1, 26, 56 (with tIceTop = 0 ) Depth (km / ms) 0 / 0 1.45 / 4.8 DOM 1 1.88 / 6.3 DOM 26 2.39 / 7.9 DOM 56 39 30 29 21 From ICRC presentation by Tom Gaisser
IceTop waveform and shower reconstruction Fat-reader can be used to extract coincident in-ice/IceTop events (mode=4 mmin=2), to save them into a .hit-format file (-f) and to reconstruct both in-ice muon (rmsk&1) and IceTop shower (rmsk&4). IceTop waveform feature-extracted parameters are leading edge and charge. Two ways of combining ATWD waveforms are implemented: combined (dsat=0) or highest unsaturated (dsat=1).
IceTop and in-ice coincidences The more vertical zenith angle of the reconstructed muons could be due to the shower curvature: Since the muon passes close to the string at depth, the shower core (which is close to penetrating muon) is far from the IceTop array, i.e. IceTop sees the curved part of the shower. The angle difference should be proportional to the zenith angle if this is the case.
Conclusions • In-ice/IceTop coincidences are observed and are consistent with muon hypothesis in-ice with the corresponding shower on the ice surface • in-ice muons are reconstructed with somewhat more vertical zenith angles than zenith angle of the plane fit to the shower front. This can be (at least partially) explained by the geometry of the coincident event and shower front being curved • Coincident event data can be extracted with the fat-reader for offline analysis (takes a few seconds per file).