14-17 September 2021
America/Los_Angeles timezone

LArQL: A phenomenological model for treating light and charge generation in liquid argon

14 Sep 2021, 10:30
Light/charge response in noble elements Light/Charge Response (1B)


Franciole Marinho (UFSCar)


Experimental data shows that both ionization charge and scintillation light in LAr depend on the deposited energy density (dE/dx) and electric field (𝜉). Moreover, free ionization charge and scintillation light are anticorrelated, complementary at a given (dE/dx, 𝜉) pair. We present a phenomenological model, called LArQL, that provides the anticorrelation between light and charge and also its dependency on the deposited energy as well as on the electric field applied. The model is built with three parameters to be fitted to data: ionizations per energy unit, number of excitations/ionizations, and the fraction of escaping electrons, as function of deposited energy. LArQL modifies the Birks (or Box) charge model considering three aspects: 1. at 𝜉 = 0, escaping electrons are taken into account; 2. just above 𝜉 = 0 field extracted electrons are added; 3. at higher fields, escaping electrons tend to zero and the Birks model is recovered. Deviations from current Birks Law are observed only for LArTPC operating at low ξ and for heavily ionizing particle (stopping protons). The model presents a satisfactory description at dE/dx and field ranges for interacting particles in LArTPCs and fits well the available data. Improvements via data sets compilation and “global” fits are also interesting features of the model.

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