The cosmic ray radio detector data acquisition system

Cosmic rays with kinetic energy larger than 10/sup 20/ eV have been detected by two experiments, AGASA and HIRES. The nature and origin of these particles are not known. Acceleration mechanisms that can produce particles at these energies could be due to yet unknown sources of energy. The extreme energy cosmic rays (EECR) are rare reaching earth at a rate of few per square kilometer per year. The rarity of these events implies that large detector arrays are required making construction cost one of the main issues. We are exploring the possibility to detect EECR using bi-static radar technique. For a proof of principle we use broadcast TV stations as source of RF. After our first round of data taking, a more reliable DAQ was built addressing problems found such as loss of data and inaccurate time stamping. The new DAQ design uses a real time operating system and multithreaded software. To solve the time stamping problem, a GPS bit stream and the precision 1 pps are now included in the data stream.