Software digitizer for high granular gaseous detector

A sampling calorimeter equipped with gaseous sensor layers with digital readout is near perfect for "Particle Flow Algorithm" approach, since it is homogeneous over large surfaces, robust, cost efficient, easily segmentable to any readout pad dimension and size and almost insensitive to neutrons. The response of a finely segmented digital calorimeter is characterized by track efficiency and multiplicity. Monte Carlo (MC) programs such as GEANT4 simulate with high precision the energy deposited by particles. The sensor and electronic response associated to a pad are calculated in a separate "digitization" process. We developed a general method for simulating the pad response, a digitization, reproducing efficiency and multiplicity, using the spatial information from a simulation done at higher granularity. The digitization method proposed here has been applied to gaseous detectors including Glass Resistive Plate Chambers (GRPC) and MicroMegas. Validating the method on test beam data, experimental observables such as efficiency, multiplicity and mean number of hits at different thresholds have been reproduced with high precision.Comment: Proceeding for MPGD 201

Correlation between electrons and vortices in quantum dots

Exact many-body wave functions for quantum dots containing up to four interacting electrons are computed and we investigated the distribution of the wave function nodes, also called vortices. For this purpose, we evaluate the reduced wave function by fixing the positions of all but one electron and determine the locations of its zeros. We find that the zeros are strongly correlated with respect to each other and with respect to the position of the electrons and formulate rules describing their distribution. No multiple zeros are found, i.e. vortices with vorticity larger than one. Our exact calculations are compared to results extracted from the recently proposed rotating electron molecule (REM) wave functions