Space Charge - Thomas-Ham/larreco GitHub Wiki

Space charge effect (SCE) means that the E-field isn't uniform across the detector. The recombination factor used when calculating shower energy, for example, is a function of the electric field. So we use a map to obtain the local E-field at a given point in the detector and tweak the nominal recombination factor accordingly. In the case of showers, we calculate the (charge weighted) centre of the shower in the detector and use the E-field which corresponds to this point for calculation downstream. This means each shower has it's own recombination factor.

To access the map which gives the local E-field we need to merge the larreco and lardataalg repositories with the following branches:

https://github.com/etyley/larreco-1/tree/feature/etyley_sce

https://github.com/etyley/lardataalg/tree/feature/etyley_sce

(see https://sbn-docdb.fnal.gov/cgi-bin/private/ShowDocument?docid=18548)