Pre-shower is a detector of the multi-pixel kind, made up of 625 LYSO crystals, located in a 10x10 cm matrix, which sparkle when a particle deposits part of its energy on them. The spectrum of emitted light is around 360[nm]. This light is then canalized through WLS fibers (Wave Length Shifter) that transform its spectrum to greater wavelengths, to be later directed by small waveguides to photon-counting devices, known as MPPC (Multi-pixel Photon Counters) which have a sensitivity peak at around 450[nm].
This project is part of the collaboration for the NA64 Experiment (formerly known as P348), which broadly focusses on the search of dark matter using one of the lines from CERN´s Super Photon Synchrotron accelerator (SPS). The Pre-shower calorimeter’s pixelated design provides the transversal coordinate of a particle beam and estimates its energy before this one impact on an electronic calorimeter.
In July of 2016 starts NA64, and the Pre-shower will be used for the detection of synchrotron radiation, which are high energy photons emitted when a high energy charged particle is diverted by a magnetic field. Together with the rest of the detectors of the NA64 experiment, using missing energy reconnaissance techniques it is expected to obtaining enough statistical data to better know the rate of pion decay and ethas. It is speculated that some decays involve photons and other dark bosons which – if observed – would prove the existence of dark matter.
Funds provided: Basal Founds