energyspectrumofprimarycosmicraysintheenergyregion（21页）.doc

The Cosmic Ray Spectrum at Ultrahigh Energies M.I. Pravdin for Yakutsk Collaboration Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy, 31 Lenin Ave., 678980 Yakutsk, Russia  Estimation of EAS Energy by a Calorimetric Method M.I. Pravdin for Yakutsk Collaboration Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy, 31 Lenin Ave., 678980 Yakutsk, Russia A plan of the location of detector stations of the Yakutsk EAS Array  Station of Yakutsk EAS Array  The diagram of the trigger of the Yakutsk EAS array Each trigger station has 2 scintillator detectors (Sdet=2 m2). The coincidences within a resolving time 2.0 - 2.2 μs is required. EAS is selected when an event is registered simultaneously by three neighboring stations forming a triangle. Resolving time in this case equals 40 μs Red triangles - trigger-500 (now - 63 cells, SII=7.2 km2; up to 1992 - 19 cells SI =2.5 km2) Blue ones - trigger-1000 (now - 24 cells, SII = 10.5 km2) Green circle - 10 stations of the trigger-1000, working from 1973 up to 1990 (24 + 16=40 cells, SI = 17.3 км2) Estimation of shower energy E0The calorimetric method The relation between parameters S300 or S600 and primary particle energy E0 for EAS close to the vertical has been determined by the calorimetric method. For the average showers with different S300 or S600 E0 is estimated as the sum separate a components: E0 = Ei + Eel + Eμ+ Eμi + Eν + Eh Ei = k(( is the energy lost by a shower over the observation level. It is estimated by measurements of total Cerenkov light flux (, and k = 2.16(104 / (0.37 + 1.1((Xm /1000) in the interval of light waves 300-800 nm, In view of mean atmospheric transmittance. Eel = 2.2(106(Ns((N is the energy conveyed below the array level. It is estimated by the attenuation length (N of the number of charged particles Ns through the atmosphere depth; E( = (((N( is the energy of the muon component. It is estima