75 research outputs found
The STM32 microcontroller based pulse intensity registration system for the neutron monitor
We present the outlines of a new microcontroller based data acquisition
system which is aimed for reliable operation in a typical cosmic ray particle
registration experiment. The system supports connection of up to 16 input
signals and ensures the following operation functionality: (1)stable monitoring
of the intensity of a digital pulse signal, or digitization of a continuous
potential level with a low time resolution (typically, in the limits of
1-100s); (2)registration of a continuous high-resolution (up to 5-10us) time
series of the intensity of input signal; (3)synchronization of registered time
series with both external (physical) or local (program-based) trigger signal;
(4)possibility of an on-the-fly change of the whole configuration of
informational system (both the combination and type of input signals, time
resolution and sum duration of the time series measurements, trigger logic,
etc) immediately in operation time through convenient communication with a
plain text message in dialog mode. In particular, the considered system is
applied now for a long-term, high precision measurement of the counting rate of
neutron signals at the NM64 type neutron supermonitor of the Tien~Shan mountain
cosmic ray station, with a real-time representation of the whole collected
dataset in a WWW database.Comment: communication at ISVHECRI 2016 and at the "10 Years Neutron Monitor
Database" NMDB Worksho
About long term modulation of cosmic rays in the 23-24 solar activity cycles
Recently, there has been a significant trend in magnetic fields on the Sun. The total magnetic field of the Sun
from the end of the 22nd cycle of solar activity (SA) has more than halved and this decrease continues. Chan-
ges in the magnetic field are the key to all the active phenomena occurring on the Sun and in the heliosphere
and, accordingly, to processes in cosmic rays. In long-term CR variations in 23-24 cycles of SA the attenuation
of the solar magnetic field is displayed and these variations turned out to be the smallest for the entire time of
CR observations. Model calculations of CR modulation for 21-22 and 23-24 cycles of SA showed: with a slight
difference in the regression characteristics obtained, the distribution of contributions to the generated CR
modulation from the effects of various SA indices is strongly varies in the analyzed periods. Possible reasons
for the features of the last two CA cycles are discussed
Cutoff rigidity and particle trajectories online calculator
Over the years, many authors have developed unique software packages for calculating the geomagnetic cut-
off rigidities and the asymptotic directions of particle arrival. Such programs are used for mass calculations
and require some skill. However, it is often necessary to carry out single calculations with the same accu-
racy. For this purpose, calculator programs have been created on the basis of already developed software
packages. One of such programs, a calculator, is described in this work
Comparison of long-term variations of the cosmic ray flux from the network of ground-based detectors, PAMELA and AMS-02 data
The paper presents preliminary results of a comparison of long-term variations of the cosmic ray flux using
data from the network of ground-based detectors with direct flux measurements on the PAMELA and AMS-02
magnetic spectrometers and a series of balloon stratospheric soundings. The analysis showed good agreement
for the entire period of continuous ground-based monitoring of cosmic ray variations
Magnetospheric effects on cosmic rays during the magnetic storm of March 2015
Cosmic ray variations of magnetospheric origin during the magnetic storm on 17th of March 2015 were studied. Cosmic ray intensity data were obtained from the neutron monitor database (NMDB) and the data of the Dst index were taken from World Data Center for Geomagnetism, Kyoto. The global survey method was employed for the calculation of changes in the cutoff rigidities throughout the storm. A correlation analysis between the Dst index and the calculated cutoff rigidity variations was performed for each cosmic ray station. The most essential decrease in cutoff rigidities occured when the Dst index was around the value of -234nT. A latitudinal distribution of the cutoff rigidities was acquired, showing that the maximum effect took place at mid-latitude stations with rigidities around 8-10GV. During the examined event the maximum change in cutoff rigidity was observed at Athens station where the decrease of the cutoff rigidity reached the value of 1.07GV. Furthermore, corrections of cosmic ray intensity due to the magnetospheric effect were calculated using the derived cutoff rigidities showing a discperancy with the observed values at mid- and low- latitude stations
Relationship of the characteristics of large Forbush decreases and the heliolongitude of their sources
In this investigation the different features and characteristics of Forbush decreases, with emphasis on large For-
bush decreases (â„4%) and their association to solar sources, are being examined. According to the heliolongitude
of the solar source, the events under study were separated into three subcategories: western (21Âș †heliolongitude
†60Âș), eastern (-60Âș †heliolongitude †-21Âș) and central (-20Âș †heliolongitude †20Âș). The selected events cover
the time period 1967 - 2017. The âGlobal Survey Methodâ was used for analyzing the Forbush decreases, along with
data on solar flares, solar wind speed, geomagnetic indices (Kp and Dst), and interplanetary magnetic field. In ad -
dition, the superimposed epoch method was applied in order to plot the time profiles for the aforementioned group
of events. This detailed analysis reveals interesting results concerning the features of cosmic ray decreases in re-
gard to the heliolongitude of the solar sources. Moreover, it is also shown that large Forbush decreases, regardless
of the heliolongitude of the solar source, are accompanied by increased geomagnetic activity and increased aniso-
tropy, including anisotropy before the events, which can serve as a typical precursor of Forbush decreases
Unusual decrease of the cosmic ray intensity in May 2019 on the background of the minima solar activity
In May 2019 there was a long and sloping decreasing of cosmic rayâs intensity (up to ~4%), which was observed
on neutron monitors. Despite this was a small decreasing compared to quasi-eleven-period variation, it stands
out well in 24th cycle of solar activity.
According to LASCO/SOHO and STEREO-A data from spectrometer in different UHF bands and from coronograph,
there was a series of CMEs which affected on modulation of cosmic rays by creating a series of Forbush decrea -
sing, which didnât restore. This series was connected to two active regions on sun and began on April 30 from
âreversed haloâ CME. This CME didnât reach the earth, but led to significant additional modulation of cosmic rays,
mostly on east side. Later there was a series of smaller CMEs on May 1-6, which also didnât reach the earth, but
were gradually approaching to Earth. Recent CMEs on 8-9 and 12-13 created a normal Forbush decreasing.
In May 2019, cosmic rays shown again, that they can collect information about distant objects of geliosphere and
transmit it to Earth. The ground-level detectors sometimes can observe an interaction of interplanetary distur-
bances, which didnât reach the earth. East CMEs are especially effective, because they closing magnetic field
lines beyond the orbit of earth and can interfere the restoring of cosmic rayâs intensity
Snow effect on the neutron monitor network for 2018-2019
In this article, the influence of the surrounding snow cover on the neutron monitors count rate of the world network of neutron monitors was estimated using the method of reference stations. The applied technique also makes it possible to estimate the snow cover thickness at the observation point, which was done for more than two dozen stations. A comparison of the data correction results for snow is carried out for the case of automatic correction, based on the developed algorithm, and for manual one, with an error estimate
Potential of Core-Collapse Supernova Neutrino Detection at JUNO
JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve
Detection of the Diffuse Supernova Neutrino Background with JUNO
As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO
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