Muon Telescope Research Articles

Temperature effect of muons registered under the ground in Yakutsk by telescopes on GAS-discharge counters

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.

Design, fabrication and large scale qualification of cosmic muon veto scintillator detectors

The INO collaboration is designing a cosmic muon veto detector (CMVD) to cover the mini-ICAL detector which is operational at the IICHEP transit campus, Madurai in South India. The aim of the CMVD is to study the feasibility of building an experiment to record rare events at a shallow depth of around 100 m, and use plastic scintillators to veto atmospheric muons from those produced by the rare interactions within the target mass of the detector. The efficiency of such a veto detector should be better than 99.99% and false positive rate should be less than 10-5.The CMVD is being built using extruded plastic scintillator (EPS) strips to detect and tag atmospheric muons. More than 700 EPS strips are required to build the CMVD. Two EPS strips are pasted together to make a di-counter (DC) and wavelength shifting fibres are embedded inside the EPS strips to trap the scintillation light generated by a passing cosmic ray muon and transmit it as secondary photons to the Silicon Photo-Multipliers (SiPMs) mounted at the two ends of the DCs. Since the efficiency requirement of the veto detector is rather high, it is imperative to thoroughly test each and every component used for building the CMVD. A cosmic ray muon telescope has been setup using the DCs to qualify all the DCs that will be fabricated. In this paper we will discuss the details of the design and fabrication of the DCs, the cosmic muon setup and the electronics used for their testing and the test results.

A large-area MRPC detector for muon scattering tomography

A muon telescope equipped with four multi-gap Resistive Plate Chambers of 2 m2 per plane was tested with the muon scattering tomography technique. The telescope was operated during several hours with high atomic number materials located at its center with two detector planes on each side. With an intrinsic efficiency above 98%, spatial resolution around 1 cm and detector planes spaced by 45 cm, it was possible to identify the presence of a 5 cm thick tungsten block in 10 min of acquisition. The results obtained after five hours of acquisition are also presented in this communication.

A GEANT4 based simulation framework for the large area muon telescope of the GRAPES-3 experiment

The GRAPES-3 experiment located in Ooty, India, samples the electron and muon components in extensive air showers using an array of plastic scintillator detectors and a muon telescope (G3MT) consisting of proportional counters to study the composition of primary cosmic rays (PCRs) as well as γ-ray sources in the TeV–PeV energy range. The G3MT is designed with an appropriate mass absorber to shield the electromagnetic and hadronic components in the shower and to detect muons above 1 GeV×sec(θ) energy, incident from a zenith angle θ. We developed a simulation framework based on the GEANT4 toolkit to evaluate the response of shower particles such as muons, γ-rays, electrons and hadrons in the G3MT. We discuss the geometric modeling of the G3MT using GEANT4 starting with the proportional counter. We estimated the punch-through contribution of hadrons in the G3MT. We compare the simulated muon multiplicity distributions with the observed ones assuming PCR composition from a four population supernova remnant acceleration model namely H4a.

Development of a large-area, light-weight module using the MALTA monolithic pixel detector

The MALTA pixel chip is a 2 cm × 2 cm large monolithic pixel detector developed in the Tower 180 nm imaging process. The chip contains four CMOS transceiver blocks at its sides which allow chip-to-chip data transfer. The power pads are located mainly at the side edges on the chip which allows for chip-to-chip power transmission. The MALTA chip has been used to study module assembly using different interconnection techniques to transmit data and power from chip to chip and to minimise the overall material budget. Several 2-chip and 4-chip modules have been assembled using standard wire bonding, ACF (Anisotropic Conductive Films) and laser reflow interconnection techniques. These proceedings will summarise the experience with the different interconnection techniques and performance tests of MALTA modules with 2 and 4 chips tested in a cosmic muon telescope. They will also show first results on the effect of serial power tests on chip performance as well as the impact of the different interconnection techniques and the results of mechanical tests. Finally, a conceptual study for a flex based ultra-light weight monolithic pixel module based on the MALTA chip with minimum interconnections is presented.

Characterization and On-Field Performance of the MuTe Silicon Photomultipliers

The Muon Telescope, MuTe, is an instrument for imaging volcanoes in Colombia. It consists of a scintillator tracking system and a water Cherenkov detector for particle energy measurement. The Muon Telescope operates autonomously in high-altitude environments where the temperature gradient reaches up to 10 °C. In this work, we characterize the telescope silicon photomultipliers’ breakdown voltage, gain, and noise for temperature variations spanning 0 to 40 °C. We demonstrate that the discrimination threshold for the Muon Telescope hodoscope must be above 5 photo-electrons to avoid contamination due to dark count, crosstalk, and afterpulsing. We also assess the detector counting rate depending on day-night temperature variations.

Shielding Cosmic Ray Muon using Copper and Aluminium Sheets Composited with Polyethylene Sheets for a Better Protection

Muons are usually among the most common secondary cosmic ray particles on Earth's surface. Muon research has confirmed their occurrence in a variety of locales. It has been claimed that cosmic radiation in general, and muons in particular, have disastrous consequences on biological things and electrical components on Earth and in space. According to medical sources, cosmic rays have been linked to many ailments affecting people and other creatures. Because of these issues, cosmic ray shielding has become a crucial component of this and comparative studies. Muons emitted by cosmic rays were detected using a muon telescope made of coaxial Geiger-Muller (GM) tubes. This experiment was carried out within the muon lab of Universiti Kebangsaan Malaysia (UKM) in Malaysia to examine how the cosmic ray muon count fluctuates with the shielding of metals (Copper (Cu) and Aluminium (Al)) and polyethylene. The measured muon count for each metal sample was statistically analysed. Using both metals as shielding in this experiment revealed that adding additional Cu and Al sheets reduced the muon count. Generally, the numbers drop as the thickness increases. The results suggest that Cu outperforms Al in shielding efficacy (19% vs 16%). Because Cu has a more significant density than Al, the correlation coefficient R2 for Cu = 0.9372 is greater than R2 for Al = 0.6593, indicating that the trend for Cu is better than the trend for Al in this experiment. To study the shielding capabilities of the two composites, Al/PE and Cu/PE, ten sheets of Polyethylene (PE) were gradually put individually between the Al and Cu sheets. The results showed that PE sheets slightly increased cosmic ray shielding.

Probing solar storms with GRAPES-3 scintillator detectors

The GRAPES-3 muon telescope in Ooty, India detected a 2-h burst of cosmic ray muons (Eμ⩾1GeV) on 22 June 2015 upon the arrival of a strong coronal mass ejection which triggered a G4 class geomagnetic storm. A detailed study of this event with the aid of Monte Carlo simulations suggests that the observed excess muons are due to a weakening of Earth’s magnetic field caused by reconnection of the strong Bz component of interplanetary magnetic field with that of Earth (Mohanty, 2016). This caused a lowering of the geomagnetic cutoff rigidity and led to the entering of excess threshold cosmic rays into the Earth’s atmosphere. The event was also analyzed with the data recorded by the GRAPES-3 scintillator detector array. These detectors record cosmic ray shower particles above a few MeV energy in contrast to GeV threshold of the muon telescope, but they lack directional information. Here, we will present these results and compare them with the results from the muon telescope. We will discuss the relevance of these results to the space weather prediction.

Searching for the Sun cosmic shadow with a ground-based, portable muon telescope: The TRIPHON experiment

Objects of the Solar System can screen the cosmic rays as seen from the Earth. In particular, the cosmic shadows of the Moon and of the Sun have been observed in the last years by very large observatories. The latter can reveal details on the solar activity and magnetic field, an information which can be of high interest to better understand its internal dynamics. We report here on the possibility to perform such a study with much smaller and portable instruments. A compact muon telescope of active area 50 × 50cm2 was mounted on a motorized platform and followed the Sun during more than 7 months. By selecting muons close to the horizon, the data exhibit a small muon deficit in the direction of the Sun. These results suggest that a network of muon telescopes may be an interesting tool in the future for the continuous monitoring of the solar activity.

The MURAVES muon telescope: a low power consumption muon tracker for muon radiography applications

Muon Radiography or muography is based on the measurement of the absorption or scattering of cosmic muons, as they pass through the interior of large scale bodies, In particular, absorption muography has been applied to investigate the presence of hidden cavities inside the pyramids or underground, as well as the interior of volcanoes’ edifices. The MURAVES project has the challenging aim of investigating the density distribution inside the summit of Mt. Vesuvius. The information, together with that coming from gravimetric measurements, is useful as input to models, to predict how an eruption may develop. The MURAVES apparatus is a robust and low power consumption muon telescope consisting of an array of three identical and independent muon trackers, which provide in a modular way a total sensitive area of three square meters. Each tracker consists of four doublets of planes of plastic scintillator bars with orthogonal orientation, optically coupled to Silicon photomultipliers for the readout of the signal. The muon telescope has been installed on the slope of the volcano and has collected a first set of data, which are being analyzed.

Reduction of Greenhouse Gases impact in the EEE Project

The whole Extreme Energy Events (EEE) array is composed of 61 telescopes installed in Italian High Schools, built and operated by students and teachers, constantly supervised by researchers. The muon telescope of the EEE Project is made by 3 Multigap Resistive Plate Chambers (MRPC). The unconventional working sites are a unique test field for checking the robustness and the low-ageing features of the MRPC technology for particle tracking and timing purposes. The MRPCs are fluxed with a standard mixture (98% C2H2F4 - 2% SF6) of greenhouse gases (GHG) phasing out of production. The EEE Collaboration is currently studying alternative mixtures environmentally and economically sustainable. The EEE Collaboration actions to reduce the Global Warming Potential (GWP) in the MRPC array of the EEE experiment are progressing.

Automatized characterization of a 2D-multiplexed Micromegas detector for muon tomography

Muon tomography consists in using cosmic muons to probe structures in a neither invasive nor destructive way. Following the first muography of a water tower using a muon telescope based on micro-pattern gaseous detectors and developed at CEA Saclay in 2015, the gaseous detectors and electronics have been developed to be more robust to high variations of temperature, allowing to operate in Egypt for the ScanPyramids mission since 2016. More recently, simulations showed that muon telescopes based on multiplexed Micromegas detectors could also be used to detect cavities for geology studies or dismantling of nuclear facilities leading to several partnerships with industry.However, telescopes are directional and have a limited compactness. To expand the spectrum of applications, CEA is developing a highly pixelated and 2D-multiplexed compact time projection chamber that would allow a full track reconstruction with a quasi-isotropical angular acceptance.The characterization of the Micromegas readout plane using a fully automatized test bench with precise positioning is presented here.

Borehole cylindrical detector: A compact muon telescope for muon radiography applications

Muon Radiography (or muography) is a recent imaging methodology that uses cosmic muons to investigate the interior of large objects, such as volcanoes, mines or buildings. Some applications are intended to use muography to search for hidden cavities in the subsoil. In many cases the muon telescope needs to be installed underground, inside tunnels, excavated chambers or drilled holes. Usually places available to install the muon detector are difficult to access for people; we thus constructed a very compact cylindrical muon tracker to deal with this problem. Thanks to its shape the detector can be inserted in boreholes. It is 1 m high and has a 24 cm diameter; these dimensions are ideal to fit a realizable drilled well. It is composed of bar and arc-shaped plastic scintillators. The original geometry of sensitive elements allows to maximize the acceptance, minimizing the dead spaces. The new borehole cylindrical detector has been tested in laboratory and the result of a measurement of open sky muon flux is in good agreement with expectations. A first application on field is currently ongoing to validate the capability of the telescope to reveal the presence of underground voids.

Muon detector for underground tomography

We utilize cosmic ray muons to explore hidden underground archaeological structures. Presented here is the design, simulation studies and first laboratory results of a compact, scintillators based, cosmic ray muon telescope for underground muon radiography.

A horizontally scalable online processing system for trigger-less data acquisition

The vast majority of high energy physics experiments rely on data acquisition and hardware-based trigger systems performing a number of stringent selections before storing data for offline analysis. The online reconstruction and selection performed at the trigger level are bound to the synchronous nature of the data acquisition system, resulting in a trade-off between the amount of data collected and the complexity of the online reconstruction performed. Exotic physics processes, such as long-lived and slow-moving particles, are rarely targeted by online triggers as they require complex and nonstandard online reconstruction, usually incompatible with the time constraints of most data acquisition systems. The online trigger selection can thus impact as one of the main limiting factors to the experimental reach for exotic signatures. Alternative data acquisition solutions based on the continuous and asynchronous processing of the stream of data from the detectors are therefore foreseeable as a way to extend the experimental physics reach. Trigger-less data readout systems, paired with efficient streaming data processing solutions, can provide a viable alternative. In this document, an end-to-end implementation of a fully trigger-less data acquisition and online data processing system is discussed. An easily scalable and deployable implementation of such an architecture is proposed, based on open-source distributed computing frameworks capable of performing asynchronous online processing of streaming data. The proposed schema can be suitable for deployment as a fully integrated data acquisition system for small-scale experimental apparatus, or to complement the trigger-based data acquisition systems of larger experiments. A muon telescope setup consisting of a set of gaseous detectors is used as the experimental development testbed in this work, and a fully integrated online processing pipeline deployed on cloud computing resources is implemented and described.

A proposal to extend the spectrographic global survey method

We present a modified spectrographic global survey method to split the cosmic ray variations into components of the interplanetary, geomagnetospheric, and atmospheric origin from ground-based observations of the cosmic ray intensity. We show a possibility to use all the available suite of ground-based instrumentation recording cosmic rays (global network of the neutron monitors located at different locations and altitudes, ground- and underground-based muon telescopes, etc.) for such studies without involving the data from aerologic atmospheric sounding. As a demonstration of the method functionality, we provide the calculation results for the variations in the isotropic flux, pitch angle anisotropy of primary cosmic rays in the interplanetary space, changes in the planetary system of geomagnetic cutoff rigidities for every observational hour, as well as the atmosphere temperature above the point of observation of cosmic ray charged components for selected time intervals.

Peculiarities of sporadic variations in density and anisotropy of galactic cosmic rays in solar cycle 24

In this work, we have processed data from the global network of neutron monitors and muon telescopes by the global survey method to study variations in the density and anisotropy of galactic cosmic rays during Forbush decreases observed in solar cycle 24. The simultaneous use of two different type detectors made it possible to examine the temporal dynamics of the angular distribution of cosmic rays in two different energy intervals. Besides, we have used measurements of the Yakutsk cosmic ray spectrograph after A.I. Kuzmin to assess the energy spectrum index during large disturbances of the interplanetary medium in this cycle. Analysis of the results obtained confirms our early statements that solar activity cycle 24 features an increased level of turbulence in the interplanetary magnetic field.

Особенности спорадических вариаций плотности и анизотропии галактических космических лучей в 24-м цикле солнечной активности

In this work, we have processed data from the global network of neutron monitors and muon telescopes by the global survey method to study variations in the density and anisotropy of galactic cosmic rays during Forbush decreases observed in solar cycle 24. The simultaneous use of two different type detectors made it possible to examine the temporal dynamics of the angular distribution of cosmic rays in two different energy intervals. Besides, we have used measurements of the Yakutsk cosmic ray spectrograph after A.I. Kuzmin to assess the energy spectrum index during large disturbances of the interplanetary medium in this cycle. Analysis of the results obtained confirms our early statements that solar activity cycle 24 features an increased level of turbulence in the interplanetary magnetic field.

Cosmic ray observations from Livingston Island

ORCA, from the Spanish name Observatorio de Rayos Cósmicos Antártico, is a cosmic ray detector devoted to the observation of secondary cosmic rays at Juan Carlos I Spanish Antarctic Base (62°39′46″S,60°23′20″W, 12 m above sea level). ORCA was installed at the beginning of January 2019 after performing a latitudinal survey from Vigo (Spain) to Livingston Island aboard the Sarmiento de Gamboa Research Vessel. ORCA was in commissioning phase from January 2019 to March 2020, being in normal operation mode from March 2020. A vertical cutoff rigidity of 2.37GV has been computed at ORCA location and during the first year of operation, i. e. from March 2020 to March 2021.ORCA consists of three detectors stacked in a shared structure that maintains the relative distances between the detectors. A muon telescope (ORCM), a neutron monitor without any shielding around (ORCB) and a 3NM64 neutron monitor (ORCA). This configuration allows the measurement of neutron count rates at two different energy thresholds, muon count rate and muon incident directions.Measurements recorded during the first year of operation and ORCA potential capabilities are shown in this work.

Three years of muography at Mount Etna: results and perspectives

The summit craters system represents the point of maximum expression of the persistent tectonic activity at Mount Etna volcano. The Muography of Etna Volcano (MEV) project began in 2016 as a pilot project for the successive installation of a permanent muographic observatory. It aims to demonstrate the detector’s capability to observe density anomalies inside the volcanic edifice and monitor their time evolution. The first muon telescope built by the collaboration and installed at the base of the North-East crater from August 2017 to October 2019 was already able to get significant results. This work describes the characteristics of the muon-telescope and summarizes the principal outcomes obtained, with a quick look at the current status of the project and future developments.