Speaker
Description
To match the physics goals of future Higgs factory to secure the required precision of luminosity measurement, luminosity detectors need to be positioned with micrometer precision.
Last year, prototype of a highly compact and granular positron calorimeter (ECAL-P) for LUXE experiment was tested at the DESY electron beam. The design of ECAL-P was based on the concept proposed for luminosity calorimeters at future e+e- colliders. For calorimeter alignment, additional silicon sensor layer was placed in front of the calorimeter. An edge-detection procedure based on Hough Transform can be then used to find position of the front sensor pads in the reference frame of the beam telescope.
A novel alignment algorithm has been developed and implemented for the calorimeter test data analysis. With huge statistics of collected electromagnetic showers not only the calorimeter position with respect to the beam telescope but also the internal structure of the calorimeter can be established with micromicron precision from the dedicated likelihood fit to the data. Accuracy of the algorithm was also verified with the Monte Carlo data from Geant4 simulation of the test setup.