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Stephanie's Homepage
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Level 2
This page gives an overview of trigger level, pole filter and level 2 cuts.
Trigger (level 0)
The cascade trigger for IC40 is as follows:
- SMT > 8
In ice simple multiplicity trigger is a prescaled minimum bias trigger that requires 8 DOMs hit within a 5000ns window. Local coincidence is LCSpan==1 with a 1000ns time window.
Some events from the EHE filter and the muon stream are also included in the cascade analysis. This is to correct for the feature extractor bug that was running at pole.
No further cuts are performed at this level, data is converted from processing and filtering (PnF) to the standard online format (.i3). GCD streams are obtained from the database.
Pole filter (level 1)
After events are picked out using this trigger the level 1 online processing reconstructions are run (linefit, dipolefit, muon-llh-reco). In order to run these reconstructions information from the badDOMs list is used to filter out badDOMs, DOMcalibrator is run to create calibrated waveforms, and FeatureExtractor is run to create hits based on these waveforms. Hit cleaning is performed to eliminate early or late hits, hits are only used within the 6&mu s window that contains the most hits. The calibrated waveforms and cleaned DOMlaunches are not written to the final .i3 file since they are very large and easily reproducible.
The cascade pole filter for IC40 is as follows (2008 TFT cascade filter propsal):
- PoleCascadeLinefit_LFVel < 0.13
Typical muon track like events travel at close to the speed of light, while cascade like events are relatively stationary. A fit using the linefit velocity can separate cascade events from background muon events by requiring a low velocity.
- PoleToI_evalratio > 0.12
Typical muon track like events are elongated, while cascade like events are more spherical. A fit using the tensor of inertia eigenvalue ratio can separate cascade events from background muon events by requiring a more spherical topology.
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Figure 1: Linefit velocity using PoleCascadeLinefit_LFVel. Figure 2: Tensor of Inertia eigenvalue ratio using PoleToI_evalratio.
Level 2
At level 2 offline processing reconstructions are run. This processing is the same as the processing that is run online in level 1, no additional cuts are made. The passing rate for level 2 from trigger level are shown in Table 1.
| . | Trigger Rate (Hz) | Level 2 Rate (Hz) |
| Experimental data | 1500 | 16.3 (1.1%) |
| Monte Carlo | 1270 | 12.5 (1.0%) |
| Atmospheric signal | 1.33 × 10-3 | 1.15 × 10-4 (8.6%) |
| E-2 signal | 2.55 × 10-4 | 1.48 × 10-4 (58.0%) |
Table 1: Passing rates for level 2 cuts.
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