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.

Data management at the Oulu cosmic ray station

With the recent electronics upgrade of Antarctic neutron monitors (NMs) DOMC and DOMB in 2019, the Oulu cosmic ray station (Sodankylä Geophysical Observatory, Finland) receives a significantly larger amount of data than before. This has led to a need for an important upgrade of the configuration of servers working at the station. The new configuration has three types of servers: a web-server, a datamaster server and data acquisition machines. The web-server provides a user interface for services of the station: the main website, the GLE database and other services. The datamaster is the main server, which stores all data in raw files and a database. Data acquisition machines are computers that directly receive data from the instruments and send the files farther to the datamaster server. This work describes technical details of the cosmic ray station setup providing reliable and secure data acquisition, handling and publication.

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.

Study of individual pulses at the Antarctic high-altitude neutron monitor DOMC

A pair of neutron monitors (NMs) is installed on the high Central Antarctic plateau, at the Concordia station (3200 m altitude) and measures the nucleonic component of nucleonic-muon-electromagnetic cascades in- duced by high-energy cosmic rays in the atmosphere. The installation includes two NMs: DOMC, a standard mini-NM, and a bare (lead-free) DOMB NM. The newly installed data acquisition (DAQ) system records in- dividual pulses corresponding to mostly neutrons in the detector’s counting tube. Here we analyze different types of pulses and study the distribution of the waiting times between individual pulses as well as the pulse height, recorded by the DOMC NM during a quiet period of January 2020. The distribution appears double- peaked with peaks corresponding to the frequency of individual atmospheric cascades and the intra-cascade variability, respectively. We discuss also the nature of different components contributing to the pulses and se - paration of the signal from noise. It is shown that the waiting-time distribution has distinguished timescales, >30 ms defined by the cosmic-ray induced atmospheric cascades, and < 10 ms reflecting the intra-cascade variability. The new DAQ system allows one to study the development of the atmospheric cascade.

A new cosmic ray observation at Syowa Station in the antarctic

A set of Cosmic Ray detectors was newly installed in Syowa Station, in the Antarctic, to observe CR neutrons and muons simultaneously at the same location. The observing system has started working in February 2018 and is in stable operation with a high operation rate, >90%. We describe the new systems and show its stability.

Local intermittency measure analysis of neutron monitor data

Local Intermittency Measure (LIM) is a development of wavelet analysis particularly suited to the diagnosis of isolated, intermittent events in time series. We construct LIM scalograms of Neutron Monitor (NM) data for an example each of a large GLE and a Forbush decrease. Both kinds of event show distinctive LIM signatures. In the case of the Forbush decrease the method also identifies a second, much smaller event that took place in the same time period. LIM may thus be a useful tool for automated or semi-automated detection of such events in NM data.

A new neutron monitor at the Juan Carlos I Spanish Antarctic Station (Livingston Island-Antarctic Peninsula)

Last January 2019, a new neutron monitor was installed at Juan Carlos I Spanish Antarctic Station (62º 39’ 46’’ S, 60º23’20’’ W, 12 m asl) located in Livingston Island (South Shetland Archipelago) close to the Antarctic Peninsula. The vertical rigidity cut-off for this new station is estimated as 3.52 GV. This new station (ORC) is composed of a BF3-based 3NM64 (ORCA) and 3 bare BF3 counters (ORCB). The neutron monitor is complemented by a muon telescope sharing a common room in a single stack. ORCA and ORCB with the Castilla-La Mancha neutron monitor (CaLMa) are the Spanish contributions to the Neutron Monitor Data Base. Because Juan Carlos I station is a summer station, one minute data is providing once a day during the Antarctic summer. One hour data are sent once a day during Antarctic winter. First measurements and future plans are provided in this work.

Upgrade of electronics of neutron monitors DOMC and DOMB

DOMC and DOMB neutron monitors (NM) operate at the Concordia research station (Dome C on the Antarctic plateau, 75 o 06’S, 123 o 23’E, 3233 m a.s.l.) since 2015. Their high elevation and proximity to the geomagnetic pole provide low atmospheric and geomagnetic cutoffs and, therefore, the exceptionally high sensitivity to low-ener- gy cosmic rays. The instruments are the so-called mini neutron monitors with BF 3 -filled counter tubes. DOMC has the standard design with a lead neutron multiplier and DOMB is a so-called “bare” (lead-free) unit. We report on a recent upgrade of the electronics heads of these instruments. The new heads have a modular architecture, built upon a single-board computer Raspberry Pi. The upgrade increases the capabilities of the instruments in two aspects: (1) measurements, particularly, of cosmic ray multiplicity; (2) remote control and monitoring. The new electronic heads register each pulse from a detector, giving a timestamp with microsecond precision, which is crucial for multiplicity measurements. Many important parameters (e.g., high voltage, pulse detection thres- holds) can be controlled and adjusted remotely with the new design. High computing power allows performing data processing on the fly. The upgrade increases the capability of DOMC and DOMB in cosmic ray measurements and improves control of the operation of the neutron monitors.

NMDB database and global survey method

The method of a global survey developed in the 1970s allows using a world-wide network of neutron monitor stations as a single multidirectional device. Wherein, receiving characteristics of each device, which reflects their geometries and geographical positions, are taken into account. Such an approach makes it possible to define the first two angular moments of the distribution function of cosmic rays in the interplanetary space at each hour of observation. With the creation in 2008/2009 and subsequent development of an international database of neutron monitors NMDB, for the first time it appeared an opportunity to use the global survey method in real-time mode. Such a situation creates a unique possibility to use the results not only for scienti- fic researches but also for space weather forecasting. To use the data of the world-wide network of neutron monitors it is necessary to carry preliminary preparations. Thereby, in the current work, the main attention is attracted to a solution to some practical questions that arise when using the NMDB in real-time.

Calibration of the operative cosmic ray detector at Marambio Base in the Antarctic Peninsula

During 2019 an Antarctic Space Weather Laboratory was deployed at Marambio base in the Antarctic Peninsula. The main instrument installed was a cosmic ray detector based on water Cherenkov radiation (WCD). This detector is the first permanent Antarctic node of the LAGO (Latin American Giant Observatory) Collaboration. Long-term calibrated observations of the WCD will be presented here. Finally, the global galactic cosmic rays variability observed with the WCD will be compared with observations of a neutron monitor with similar rigidity cut off than the Marambio site.