SEASA: The Stockholm Educational Air Shower Array

An educational air shower array is under construction at the recently built AlbaNova University Center in Stockholm [1]. Each detector site consists of three plastic scintillator sheets in a triangular configuration, read-out by compact photomultiplier tubes (PMTs) through wavelength shifting bars. The PMT signals are received by a field programmable gate array (FPGA) based local data acquisition electronics system that is designed to be compact, low cost and scaleable. A commercial GPS timing module provides an accurate local clock to allow event synchronisation between the detector stations. Local control and readout are provided by a single-chip Linux system which sends data directly over the internet to a central server. Once commissioning is completed, the array will be significantly extended by the inclusion of local schools in the Stockholm region.