Multidetector Experiment on Aragats
Analyzing the condition leading to winter flux enhancements authors of [8] absolutely correct mention that “The relatively small amplitude of the disturbance of the surface electric field during the event 2019-01-09 (2 kV/m as compared to 10–30 kV/m at summer TGE) indirectly indicates that the charge of cloud layers during the considered event was significantly less than the characteristic charge of the cloud layer during summer thunderstorms.” However, afterward they formulate the wrong conclusion: “Thus, similar to the summer events of surface thunderstorm increases, the increase in the flux of energetic electrons and photons in the cold season occurs as a result of the acceleration and multiplication of electrons in the upward-directed electric field created by the cloud “.
The main cause of the mistake was using data from a few Aragats detectors only. Incorporating information from particle detectors measuring energy spectra of charged and neutral particles give comprehensive information and allow understanding physical mechanisms responsible for such a complicated phenomenon as TGE. To investigate the hour-to-hour variations of radon progeny radiation and for measuring spectral lines, we perform monitoring of the natural gamma radiation on Aragats with NaI(Tl), type 905-4 ORTEC spectrometer. Spectrometer uses 3” × 3” diameter and length crystal, has 1024 channels, and provide relative energy resolution (FWHM ∼7%) [9]. Network of large NaI crystal scintillators, overviewed by a large photocathode of PM-49 (15-cm diameter) also monitored particle flux on Aragats. The sensitive area of each NaI crystal is ≈0.032m2; the efficiency to detect a gamma ray is ≈60%. The energy threshold of two spectrometers is 300 KeV, of 3 other - 4 MeV. Numerous 1 and 3 cm thick molded plastic scintillators arranged in stacks (a network of STAND1 detectors and STAND3 detector) and in cubical structures (CUBE detector) monitor particle fluxes. Light from the scintillators is re-radiated by wavelength shifting optical fibers at larger wavelengths and propagates to photomultipliers of the type PM-115M. The DAQ electronics stores all configurations of the signals in the detector channels, see detector charts with all details in [10]. All particle detectors and spectrometers operate 7/24 and time series are available for comparisons and statistical analysis from databases of cosmic ray division (CRD) of Yerevan physics institute (YerPhI).
In Fig. 1 we show a very long flux enhancement of ≈10 hours duration, that corresponds to the disturbed values of the near-surface electric field. By 1-hour periods we show the episodes of spectral analyses shown in Fig. 2 (4 from 5) and in Table 1.