Study of the HCAL Fit-Based Noise Filters in 2012 Data

Abstract

Performance of the fit-based filters for anomalous background signals for the 2012 collision data needs to be studied and validated. These filters typically use the pulse shape to separate signal from anomalous signals. The higher pileup conditions at the Large Hadron Collider in 2012 require that the filter performance be reevaluated since the signal shape can be influenced by in-time and out-of-time pileup. Using 2012 data, we examine various noise discriminants, specifically pulse shape discriminants (isolated, flat, spike, and triangle pulse shape), the isolation based filters, as well as other statistics, for the Hadronic Calorimeter (HCAL) barrel and endcap anomalous signals. Using these, we determine which areas of the detector are persistently noisy, as well as the performance of the algorithms on 2012 data. Overall, read-out-box 8 is particularly noisy this year, and the endcap regions have an unusual number of channels flagging as noise, but these channels are contributing low energy so the current algorithms are still acceptable. I have also proposed a new configuration of the algorithms to remove over-tagging of the HCAL endcap channels. A study of the HF region and filters is also presented on 2012 data. The performance of the HBHE and HF filters on six high pile-up runs in 2012 are also studied.

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