A 100 ps multi-time over threshold data acquisition system for cosmic ray detection

Abstract

High-energy cosmic rays are one of the primary sources of information for scientists investigating the elementary properties of matter. The need to study cosmic rays with energies many orders of magnitude larger than those encountered in particle accelerators led to the development of modern detection hardware and experimental methodologies. We present a low power, low complexity data acquisition (DAQ) system with 100 ps resolution, suitable for particle and radiation detection experiments. The system uses a multiple-time-over-threshold (MToT) technique for the treatment of the output signal of photo multiplier tubes (PMTs). The system has been designed for the Hellenic Open University cosmic ray telescope, where scintillator detectors are used for the detection of extensive air showers (EAS). The use of three thresholds offers a more accurate measurement of the PMT pulses’ size and consequently of the number of the incident ionizing particles. For the evaluation of the pulse the system uses comparators and a time-to-digital converter (TDC), whereas the pulses are time-stamped using the GPS signal. The prototype card is analyzed for its noise behavior and tested to verify its performance.