1. Bagrat Mailyan, Alikhanian National Laboratory (Former YerPhI)
The energy spectra of the thunderstorm correlated electron and   gamma-ray fluxes measured at Aragats
Bagrat Mailyan, Alikhanian National Laboratory (Former YerPhI)
32nd ICRC, Beijing, China

2. How electrons can “runaway”?
Courtesy of B. Carlson
Friction on electrons in air at sea level. Shown as a function of electron energy. The axis on the right indicates the electric field strength required to produce a force on an electron equal to the frictional force.
32nd ICRC, Beijing, China

3. Runaway Breakdown or Relativistic Runaway Electron Avalanche TGFs and TGEs
32nd ICRC, Beijing, China

4. RREA Events – huge long lasting peaks in particle monitor time series
32nd ICRC, Beijing, China

5. Experimental Facilities of ASEC
ASEC detectors include neutron monitor, scintillating detectors and electric field meters, which allow to measure thunderstorm effects on various particles species and get the spectra of particles.
32nd ICRC, Beijing, China

6. Outdoor detectors installed in 2010 (CUBE and STAND)
Monte Carlo simulations of ASEC detectors were done. The passage of the thunderstorm correlated gamma-rays through the roof of the laboratory building and detectors was simulated.
32nd ICRC, Beijing, China

7. Energy deposit spectra for background cosmic rays and thunderstorm correlated particles detected on October 4, 2010
32nd ICRC, Beijing, China

8. Incident gamma-ray energy spectrum recovery
The unfolding of the gamma ray spectrum above the roof of the MAKET building at altitude of 3200 m was made in the following way:
A power spectrum with initial parameters randomly chosen from predetermined interval is generated;
This spectrum is used to simulate traversal of gamma rays via roof and ASNT detector components to finally obtain simulated energy release spectrum;
The obtained simulated spectrum is compared with experimental one; the discrepancy (quality function) and initial spectrum parameters are stored;
If number of iterations is not fulfilled go to step 1.
32nd ICRC, Beijing, China

9. Gamma-ray energy spectrum recovery for October 4, 2010 thunderstorm event
32nd ICRC, Beijing, China

10. September 19, 2009 and October 4 , 2010 thunderstorm event gamma-ray spectra
After 50 MeV cosmic ray background is prevailing.
32nd ICRC, Beijing, China

11. Simulations of RREA process
Courtesy of Levon Vanyan
32nd ICRC, Beijing, China

12. September 19, 2009 thunderstorm event electron spectrum
Using detectors with various energy thresholds the electron spectrum was estimated. Gamma-ray contamination of the electron spectrum and the electron spectrum just after the electric field is estimated by Monte Carlo methods.
32nd ICRC, Beijing, China

13. Background muon flux decrease
32nd ICRC, Beijing, China

14. Conclusions
TGE gamma-ray and electron spectra can be described by power law exponential and law functions respectively. These fact put limits on atmospheric electrical field strengths.
There are less electrons detected and the maximal energy of the measured electrons is smaller in comparison with gamma rays. Electrons loss their energy and attenuate in the air faster than gamma rays.
Two processes - avalanche development (Runaway Breakdown) and simple acceleration (transformation) in the thundercloud field should contribute in TGE.
32nd ICRC, Beijing, China

15. Thank you for your attention!謝謝