- Found another paper that gives further detail; some equations on this page are quoted from here (specifically pages 2-5): https://arxiv.org/pdf/1602.03150v1.pdf

- Total integrated charge spectrum is defined by convolution of two components: the pedestal i.e. background and signal :

- The mean charge for the SPE contribution can be found using the following equation:

- According to the link above, making the assumption that the number of photoelectrons follows a Poissonian distribution, , where,:

where is the estimate for the number of 0PE triggers and is the total number of sample triggers.

- NOTE: this analysis only works for low occupancy data

- Run 12617 (RT124; Detector AARFs, 1 waveform, FWF, RAW 10% occupancy) - specifically focusing on subrun 0, PMTID 0. The spectra are found using SPESpectrumProc.cc

- To calculate , found the numerical mean of the entire spectrum
- To calculate , rerun processor with time window shifted to get histogram of just pedestal - find numerical mean of this histogram
- To calculate :
- Normalised the charge spectrum histogram such that the integral = 1. Hence N = 1, and thus and
- Took integral of part of histogram below and including Q = 2pC (which is assumed to only include 0PE triggers), to obtain

- Repeated this process for other PMTs in this subrun:

- Statistical uncertainty on will be found by comparing the SPE mean charge from data with MC to see how much the value changes
- Plan: make a 'hybrid' charge spectra distribution, with real data noise/pedestal with MC SPE pulses
- Repeat above analysis and recalculate SPE mean charge, see how much they differ to obtain UNCERTAINTY
- Current status: HIT mixing tool in process of being adapted in order to make this hybrid, when it is ready I will have more to update!

-- AshleaKemp - 12 Sep 2016

I | Attachment | History | Action | Size | Date | Who | Comment |
---|---|---|---|---|---|---|---|

png | Charge_PMTID_0.png | r1 | manage | 31.5 K | 13 Sep 2016 - 01:50 | AshleaKemp | |

png | charge_vs_ID.png | r1 | manage | 35.0 K | 13 Sep 2016 - 22:30 | AshleaKemp |

This topic: Public > UserList > AshleaKemp > SPEMeanChargeCalculation

Topic revision: r6 - 08 Nov 2016 - AshleaKemp

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