1. IEAP CTU Project CZELTA Karel Smolek IEAP CTU 13.2. 2009

2. 2/14 Project CZELTA CZEch Large-area Time coincidence Array – project of CTU and Silesian University in Opava. Collaboration with Univ. of Alberta (project ALTA, we use the same hardware). Project for the detection of high energy cosmic rays (>10 14 eV). Stations are installed at roofs of high schools -> educational impact. Shower of particles of secondary cosmic rays.

3. 3/14 Detection station HV PC Scheme of the scintillating detector U [V] t [ns] channel 1 channel 2 channel 3 3 scintillators with photomultipliers in a triangle with a site ~10 m, work in a coincidence => detection of showers with the energy > 10 14 eV. GPS for precise time-labeling of detected showers (precision ~10 ns) => it is possible to study space and time coincidence of the detected showers. Primary particle Interaction in the atmosphere Shower of secondary particles

4. 4/14 Outer box with temperature insulation Thermostat Heating cable Wooden box With scintillating detector Socket of 230 V (heating) Thin metal tube with cable 230 V Metal tube with other cables: - high voltage for photomultiplier - signal cables from photomultiplier - cable to testing LED diode - cable for controlling of thermostat GPS antenna Hardware of the detection station

5. 5/14 Photomultiplier Light guide Scintillator Testing LED diode

6. 6/14 PC UPS GPS receiver Crates Electronics

7. 7/14 Station in Kladno

8. 8/14 Meteorological station Flux of detected showers is correlated with the atmospheric pressure. We provide the detection stations with the meteorological station, measured data are automatically stored on PC. Collaboration with the Czech Hydrometeorological Institute – they provide us all necessary historical data measured with the professional stations. Disadvantage: for some detection stations, the professional station is not near.

9. 9/14 Present situation of the project Production of detection stations in the CR  electronic boards produced in Awos Pardubice  scintillators produced in JINR Dubna in Russia First two stations installed in Prague and Opava:  IEAP CTU – 2004  Silesian University in Opava – 2005 Next three stations installed in high schools:  High school in Pardubice - 2006  Mendel’s high school in Opava - 2006  High school in Kladno - 2007

10. 10/14 Locations of detection stations CZELTA stations in the Czech Republic station in operation station in preparation

11. 11/14 Web-based interface New functionality added.

12. 12/14 Web-based interface

13. 13/14 Analysis of measured data The aim is to build the global network of detection stations on the Earth = huge „telescope” for detection of cosmic rays showers. In the measured data, unusual events are searched: - sudden increase of rate of showers - simultaneous detection of showers with distant stations Minimal energy of a primary particle, which can produce a detectable shower of secondary particles: 10 14 eV. The timing resolution of the GPS time difference between distant sites: ~16 ns. It is possible to reconstruct the direction of the flight of a primary particle. Uncertainty of reconstructed altitude angle θ of a primary particle: δθ = 4°/sin(θ) Uncertainty of reconstructed azimuth angle φ of a primary particle: δφ = 5° tt

14. 14/14 Conclusion Study of high energy cosmic rays is popular part of modern physical research. At present, the Czech Republic is involved in the unique global project of detection of high energy cosmic rays. The CZELTA project will help to solve present problems of cosmic rays. Secondary purpose of the project is to attract young students from high schools to physics, mathematics and computer sciences.