Cosmic ray research in Yerevan Physics Institute
In 1942, the famous physicists brothers Abram and Artem Alikhanian organized a scientific expedition to Mount Aragats and started cosmic ray detection with various particle detectors. They have found high-energy protons and deuterons in the flux of cosmic rays and several new unstable particles (called by them varitrons). These studies laid the foundation for the regular study of cosmic rays and many further discoveries.
The dates of the most important advances in the study of CR are presented below:
- 1944 - Foundation of the Institute of Physics and Mathematics of the Yerevan State University – subsequently Yerevan Physics Institute first director Artem Alikhanian) .
- 1945 - The foundation of highland scientific station on Mount Aragats. Experiments using Alikhanov - Alikhanyan mass spectrometer.
- 1957 - Design and start-up of the first ionization calorimeter.
- 1960 - The establishment of highland scientific station Nor Amberd.
- 1970 - Research and exploitation of spark chambers.
- 1975 - The measurement of the energy spectrum and charge ratio of the horizontal muon fluxes (experiment "muon" - T. Asatiani).
- 1976 – Allocation of 18NM64 neutron supermonitors at Aragats and Nor- Amberd research stations and registration of neutron fluxes (Kh. Babayan).
- 1977 - The identification of pions and protons using the transition radiation and energy assessment by the ionization calorimeter. (Experiment "Pion" - E. Mamidzhanyan, V. Avakian)
- 1997-2004 – The creation of MAKET-ANI and GAMMA detectors and measurement of the energy spectrum of CR in the region of "knee" (1014 - 1016 eV) - (G. Hovsepian, R. Martirosov).
- 2000 - Establishment on Aragats of the Space Weather Research Center.
- 2003 - The discovery of intense solar modulation phenomena in October - November in the low-energy charged particles and neutron fluxes (V.Babayan, N.Bostanjyan, A.Chilingarian).
- 2004. – Discovery of the mass-dependent position of the knee: very sharp knee in light nuclei energy spectra at ~3*1015 and absence of “knee” in heavy nuclei energy spectra at least till 2*1016eV (A.Chilingarian, G.Hovsepyan, A.Vardanyan).
- 2005 - The discovery of high-energy protons (E> 20GeV) during solar flares (N.Bostanjyan, A.Chilingarian).
- 2007 - Establishment of the global network of particle detectors (SEVAN) for the study of space weather and solar physics.
- 2009 – Discovery of the Thunderstorm ground enhancements (TGEs) – fluxes of electrons, gamma rays and neutrons from thunderclouds (CRD group);
- 2010 – First Observation of predicted Relativistic runaway process – acceleration and multiplication of electrons in electric fields of thundercloud (A.Chilingarian, G.Hovsepyan).
- 2011 – measurement and explanation of the neutron fluxes during thunderstorms (N.Bostanjyan, A.Chilingarian, L.Vanyan).
- 2012 – Measuring of the energy spectra of TGE electrons and gamma rays (A.Chilingarian, B.MAilyan, G.Hovsepyan).
- 2013 - Development of the comprehensive model of the TGE (A.Chilingarian, B.Mailyan, L.Vanyan)).
Currently physicists of Cosmic rays division of YerPhI with a reequipped and renewed facilities continue research in the field of galactic and solar cosmic rays, solar-terrestrial connections and space weather. The world's largest center for registration of the fluxes of elementary particles from thunderclouds, electric and geomagnetic fields, meteorological parameters and lightning occurrences was established on the slopes of Mount Aragats. The created experimental complex allows Armenian physicists play a leading role in the study of high-energy atmospheric physics.