Muon Telescope Research Articles

Candidate detection of GRB221009A by Yangbajing muon telescope

Long gamma-ray bursts (GRBs) can be generated by the collapse of a rapidly rotating massive star into a black hole and are the brightest known explosive events in the Universe. GRB221009A is the most energetic gamma-ray burst ever recorded, providing delayed detection of very high energy photons that challenge the standard propagation mechanisms, possibly suggesting exotic physics phenomena. An excess, synchronous with the ignition of GRB221009A, is detected in the rate of the Yangbajing muon telescope. A preliminary assessment of the significance of this excess limits the probability of a chance coincidence to less than 10−3. The hypothetical mechanisms for producing a muon excess induced by the GRB are exotic/puzzling. If confirmed by further investigations, this excess would add another feature to the many anomalies observed in this extreme astrophysical event.

First Results of the CREDO-Maze Cosmic Ray Project

The CREDO-Maze project is the concept for a network of stations recording local, extensive cosmic ray air showers. Each station consists of four small scintillation detectors and a control unit that monitors the cosmic ray flux 24 h a day and transmits the results to the central server. The modular design of each array allows the results to be used in educational classes on nuclear radiation, relativistic physics, and particle physics and as a teaching aid in regular school classrooms and more. As an example, we present here some preliminary results from the CREDO-Maze muon telescope missions to the Arctic and down into a deep salt mine, as well as the first shower-particle correlation measurements from a table-top experiment at Walailak University. These experiments show that the different geometric configurations of the CREDO-Maze detector set can be used for projects beyond the scope of the secondary school curriculum, and they can form the basis of student theses and dissertations at universities.

Prototype Cherenkov detector characterization for muon tomography applications

Muography is an innovative imaging technique using naturally produced elementary particles – atmospheric muons – used to determine the distribution of density inside massive objects. The modification of the particles flux – by scattering or absorption – reflects the contrasts in density within the medium and therefore offers the possibility for an image of the crossed volumes. In most muography setups the imaging process is based on the tracking of the particles which accounts for the absorption or the scattering of the muons trajectories. Neither the energy nor the identity of the particles (the so-called PID) is exploited since this information traditionally relies on the use of calorimeters and/or high intensity magnetic fields. Both these techniques hinder detector portability which in the case of muography is important and this renders them impractical for its purpose. In this paper we characterize the performance of a simple and small water Cherenkov detector capable of providing some insights on the energy of muons and the PID for the crossing particles that could potentially improve the background rejection for a muography survey when operating in conjunction with a muon telescope. We tested a prototype of such water Cherenkov detector in combination with two small muon hodoscopes. Both systems are using the same opto-electronics chain – optical fibers and pixellized photosensors – and the same data acquisition (DAQ) readout system which ensures an easy integration and implementation within presently running systems. This article presents the test setup, the detector response to cosmic muons and its performance evaluation against a basic simulation of its geometry and detection principle.

Dynamics of the energy spectrum of solar-diural variations in the intensity of cosmic rays in 22–25 cycles of solar activity

Periodic 24-hour variations in the intensity of galactic cosmic rays, continuously observed by ground-based detectors, are called solar diurnal variations. The nature of these variations lies in the existence in the interplanetary medium of an anisotropic spatial distribution of galactic cosmic rays, which arises during the interaction of these particles with the heliosphere. It is believed that the physical factors responsible for the observed anisotropy of galactic cosmic rays are the processes of convection, diffusion and their drift. The combination of these factors determines the main parameters of solar diurnal variations, such as amplitude, phase and energy spectrum. To study the energy spectrum of solar-diurnal variations, we used measurement data from muon telescopes of the Yakutsk Cosmic Ray Spectrograph after A.I. Kuzmin and Nagoya stations (Japan). The research approach is based on the idea of the crossed telescope method, originally designed to take into account the temperature effect. Due to the difference in the receiving characteristics of the crossed northern and southern directions of the above muon telescopes, the intensity variations recorded by them are sensitive to changes in the energy spectrum of solar-diurnal variations. This property was used to assess the dynamics of the energy spectrum of solar-diurnal variations for 22–25 cycles of solar activity. Analysis of the data obtained showed that in the last minimum of solar activity in 2018-2021. An anomalously early phase of solar-diurnal variations was observed. To study this phenomenon, we simulated the ratio and phase difference of a pair of northern and southern crossed directions for both muon telescopes for different types and values of the energy spectrum of solar-diurnal variations. A comparison of model calculations and observational data has made it possible to establish that during periods of minimum solar activity in the positive polarity of the general magnetic field of the Sun, a significant softening of the energy spectrum of solar-diurnal variations is observed. The reasons for the discovered phenomenon are discussed.

Мониторинг околоземного космического пространства, магнитосферы и атмосферы Земли в периоды Форбуш-эффектов в конце августа 2005 г.

We present the results of near-Earth interplanetary space, magnetosphere, and atmosphere monitoring during large-scale solar wind disturbances at the end of August 2005. The monitoring was carried out using ground-level cosmic ray (CR) observations made at the worldwide network of neutron monitors as well as muon telescopes in Yakutsk and Novosibirsk. As a result of the analysis performed by different methods, we have obtained variation properties of CRs of different rigidities in Earth’s orbit, their pitch angle anisotropy, orientation and configuration of the interplanetary magnetic field, changes in the planetary system of geomagnetic cutoff rigidities during geomagnetic disturbances, as well as mass average air temperature over CR stations equipped with muon telescopes. For the periods of geomagnetic disturbances, we have determined parameters of magnetospheric ring current and magnetopause currents.

Monitoring of near-Earth space, Earth’s magnetosphere and atmosphere during Forbush decreases in August 2005

We present the results of near-Earth interplanetary space, magnetosphere, and atmosphere monitoring during large-scale solar wind disturbances at the end of August 2005. The monitoring was carried out using ground-level cosmic ray (CR) observations made at the worldwide network of neutron monitors as well as muon telescopes in Yakutsk and Novosibirsk. As a result of the analysis performed by different methods, we have obtained variation properties of CRs of different rigidities in Earth’s orbit, their pitch angle anisotropy, orientation and configuration of the interplanetary magnetic field, changes in the planetary system of geomagnetic cutoff rigidities during geomagnetic disturbances, as well as mass average air temperature over CR stations equipped with muon telescopes. For the periods of geomagnetic disturbances, we have determined parameters of magnetospheric ring current and magnetopause currents.

PORTABLE MUON TELESCOPE FOR COSMIC RAY MONITORING

A portable muon telescope for monitoring of cosmic rays has been developed, based on GM counters shielded with lead adsorbers. The triple coincidence mode of operation results in a relatively good spatial resolution allowing to measure the cosmic ray flux, its east-west anomaly and also to detect the consequences of the special theory of relativity. The apparatus is suitable for long term observations of the cosmic ray flux and due to its simple and robust construction can also be used also for educational purposes.

Observation of thunderstorm-induced muon events in GRAPES-3 experiment

The GRAPES-3 tracking muon telescope located at Ooty (India) records short-term variations in the muon intensity during major thunderstorms, termed thunderstorm-induced muon events (TIMEs). Its excellent angular resolution, coupled with high statistics, allows us to observe subtle directional variations in muon rate. We detected 169 statistically significant events during the five-year period from 2006 through 2010. The monthly and seasonal variation patterns of the observed TIMEs were discussed, emphasizing their occurrence and climatological aspects. The annual diurnal pattern was plotted with the Carnegie curve, considering their possible causal link with the global electric circuit. The work represents the first report from any experiment for such an extended period in an uninterrupted manner.

The Ooty muon telescope reveals what climate did in 2022 summer

The Ooty muon telescope reveals what climate did in 2022 summer

Ecological transition for the gas mixtures of the MRPC cosmic ray telescopes of the EEE Project

The Extreme Energy Events (EEE) Collaboration is fully involved in an ecological transition. The use of the standard gas mixture, C2H2F4 + SF6, has stopped in favor of an alternative green mixture based on C3H2F4 with the addition of He or CO2.The choise of these new mixtures is motivated by the significant lower Global Warming Potential (GWP) to reduce the emission of gases potentially contributing to the greenhouse effect.The EEE experiment consists of 61 muon telescopes based on Multigap Resistive Plate Chambers (MRPCs), each telescope composed of 3 chambers filled with gas.Several EEE detectors are today completely fluxed with the new ecological mixture. This contribution will report recent results about the telescope performance obtained from studies with the eco-friendly alternative mixture carried out in the last years.

Evolution of the cosmic ray spectrum during a Forbush decrease

The Antarctic Cosmic Ray Observatory (ORCA) has been in continuous operation since January 2020 and in nominal phase since March 2021 at the Spanish Antarctic Base Juan Carlos I (Livingston Island, Antarctica 62°39′46′′S,60°23′20′′W at 12 m above sea level) at an effective vertical cutoff rigidity of R=2.37 GV. ORCA consists of two neutron monitors, ORC-A with three BF3 counter tubes following the NM64 standard, and ORC-B, with three bare BF3 counter tubes; and a muon telescope, ORC-M consisting of two 1 m2 scintillators with the neutron monitors between them. ORCA provides neutron count rates at two different energy thresholds (provided by ORC-A and ORC-B) and muon count rates and muon incidence directions throughout the ORCA volume. The neutron-producing cosmic rays observed in ORC-A have a lower rigidity threshold than the muon-producing ones observed in ORC-M. The relationship between them gives an idea about the change in the slope of the cosmic ray spectrum at the corresponding thresholds, 2.37 GV for ORC-A and ≈12 GV for ORC-M. This relation allows to investigate the change in the cosmic ray spectrum along the different regions in an Interplanetary Coronal Mass Ejection, i.e. the shock, the sheath and the magnetic cloud. ORCA first observations are presented, focusing on the analysis of the Forbush Decrease (FD) that happened at the beginning of November 2021. We present these observations and show the promising capabilities of the Antarctic Cosmic Ray Observatory, which represents a new concept of cosmic ray and solar energetic particle detector. The cosmic ray spectrum changes during the Forbush decrease detected in early November 2021 as seen in the change in the ratio of ORC-A to ORC-M count rates. This change is clear after the arrival of the shock and during the magnetic cloud being smoother or even flat in the sheath. In addition, the secondary muons show changes in their arrival directions along the ICME, being clear the different behavior in shock, sheath and magnetic cloud.

Solar neutron event recorded by a muon telescope in Mexico City on November 4, 2003

In association with the X28 solar flare on November 4, 2003, the muon telescope installed in Mexico City observed an enhancement in its counting rate between 19:55 and 20:00 UT. Based on a numerical simulation, we found that the entry of a high-energy solar neutron, with energy range from 0.2 to 2 GeV, is capable of producing muon flux that reach the atmospheric depth of Mexico City. Furthermore, we also found that this muon flux is of the order of 3% with respect to the average muon flux recorded by the telescope. Therefore it is very likely that the excess signals observed in the muon telescope are due to muons generated by solar neutrons in the Earth’s atmosphere.

Muon tomography with Resistive Plate Chambers for geological characterization

Muon tomography is one of several fields of applied physics that have witnessed the successful use of particle detection based on Resistive Plate Chambers (RPC). In this work, we report on an innovative project concerning transmission muography for geological characterization. For this purpose, a muon telescope built of four RPC planes was mounted on an adjustable structure and the telescope’s response to atmospheric muons was studied. Data acquisition campaigns took place at different locations for producing muographic images of the building of the Physics Department of the University of Coimbra, in Portugal. More recently, the detector was moved to an underground gallery of an old mine, where it is taking data that is being assessed in combination with the results from conventional geophysics techniques.

Monitoring of magnetospheric parameters based on cosmic ray effects in August

Using data (uncorrected for the temperature effect) from the global network of neutron monitors (GNNM), along with data from the Yakutsk muon telescope complex and the muon hodoscope URAGAN (Moscow), we have applied a modified spectrographic global survey (SGS) method to the 2018 August event in order to split cosmic ray variations into components of primary, magnetospheric, and atmospheric origin. We obtained time variations in the 4 GV-rigidity primary particle isotropic flux and pitch-angle anisotropy, as well as in the interplanetary magnetic field (IMF) orientation. We also showed variations in the geomagnetic cutoff rigidity (GCR) in Irkutsk.
 Using the obtained data on the changes in the planetary system of GCR within a simple model of a bounded magnetosphere, we have calculated some parameters of magnetospheric current systems, namely, the ring current radius, the magnetopause current radius, and the Dst index.

Updated results on the cosmic ray energy spectrum and composition from the GRAPES-3 experiment

Here, we present the updated results on the cosmic ray energy spectrum and composition analysis from the GRAPES-3 experiment over the energy range of 50 TeV to 1000 TeV since ICRC 2021. The simulation of cosmic ray showers was performed using the post-LHC high energy hadronic interaction model QGSJetII-04 and low energy hadronic model FLUKA. A detailed GEANT4 simulation of the GRAPES-3 muon telescope was performed. The composition was obtained by fitting simulated muon multiplicity distributions for proton, helium, nitrogen, aluminium, and iron primaries to the observed data. The energy spectrum connects to the direct measurements with a fairly good agreement in flux.

Мониторинг параметров магнитосферы по эффектам в космических лучах в августе 2018 г.

Using data (uncorrected for the temperature effect) from the global network of neutron monitors (GNNM), along with data from the Yakutsk muon telescope complex and the muon hodoscope URAGAN (Moscow), we have applied a modified spectrographic global survey (SGS) method to the 2018 August event in order to split cosmic ray variations into components of primary, magnetospheric, and atmospheric origin. We obtained time variations in the 4 GV-rigidity primary particle isotropic flux and pitch-angle anisotropy, as well as in the interplanetary magnetic field (IMF) orientation. We also showed variations in the geomagnetic cutoff rigidity (GCR) in Irkutsk.
 Using the obtained data on the changes in the planetary system of GCR within a simple model of a bounded magnetosphere, we have calculated some parameters of magnetospheric current systems, namely, the ring current radius, the magnetopause current radius, and the Dst index.

Highlights of the results from the GRAPES-3 experiment

The GRAPES-3 experiment is a unique, extensive air shower experiment consisting of 400 scintillator detectors spread over 25000 m^22 and a 560 m^22 muon telescope. The experiment located at Ooty, India, has been collecting data for the past two decades. The unique capabilities of GRAPES-3 have allowed the study of cosmic rays over energies from a few TeV to tens of PeV and beyond. The measurement of the directional flux of muons (E_\muμ≥1 GeV) by the large muon telescope permits an excellent gamma-hadron separation, which then becomes a powerful tool in the study of multi-TeV gamma-ray sources and the composition of primary cosmic rays. However, the high precision measurements also enable studies of transient atmospheric and interplanetary phenomena such as those produced by thunderstorms and geomagnetic storms. This paper presents some exciting new and recent results, including updates on various ongoing analyses.

Мюонные телескопы полярных станций Апатиты и Баренцбург для наблюдений малых вариаций космических лучей

The first results of the operation of a pair of muon telescopes installed at the Apatity and Barentsburg stations (Svalbard) in addition to the existing neutron monitors are presented. A technique for separating small variations against the background of stronger variations caused by solar activity is proposed. With its help, a small anisotropy of cosmic rays between the directions of reception of muon telescopes was revealed. It is still difficult to judge the reasons for such anisotropy, since the period of solar activity is 11 years, and observations were made for just over a year

Monitoring of heliosphere, magnetosphere and atmosphere via cosmic ray effects in August 2018

Using data of ground-level cosmic ray measurements on the neutron monitor network, along with data of Yakutsk muon telescope complex and muon hodoscope URAGAN (Moscow) uncorrected for temperature, we used modified spectrographic global survey method for an August 2018 event to split cosmic ray variations into components of primary, magnetospheric and atmospheric origin. Time evolutions of isotropic primary flux for different rigidities, pitch-angle anisotropy of cosmic rays, interplanetary magnetic field orientation were obtained, variations in geomagnetic cut-off rigidity in Irkutsk and average-mass temperature over charged components’ measurement sites were also shown.

Температурный эффект мюонов, регистрируемых под землей в Якутске с помощью телескопов на газоразрядных счетчиках

The Yakutsk spectrograph of cosmic rays includes a complex of muon telescopes based on gas-discharge and scintillation counters located on the surface and under the ground at depths of 7, 20, and 40 m.w.e. Using continuous observations made by muon telescopes on gas-discharge counters and data on the altitude profile of the atmospheric temperature over Yakutsk for the period from January 2016 to December 2018, we have calculated density distributions of temperature coefficients for muons detected on the surface and at various depths under the ground. To do this, we employed multivariate regression methods and principal component methods. The results obtained are compared with the results of earlier theoretical calculations. The results make it possible to correctly take into account the temperature effect in the data from the complex of muon telescopes on gas-discharge counters.