Muon identification with Deep Neural Network in the Belle II K-Long and Muon detector

To achieve high-resolution muography of compact targets in scenarios with complex logistical constraints, we are developing a portable muon detector system utilizing glass Resistive Plate Chambers (RPCs). Although RPCs are well understood and widely used, our work focuses on developing a gas-tight variant specifically tailored for a broad range of muography applications, with key design goals including portability, robustness, autonomy, versatility, safety, and cost-effectiveness. Our RPC detectors are designed with various configurations, each featuring unique characteristics and performance attributes. We investigate the temporal evolution of the surface resistivity of glass electrodes, as well as the detector efficiency at varying voltages and thresholds, over a span of several months. These RPCs have been utilized in a small-scale feasibility study on muon absorption using lead blocks. This article is part of the Proceedings of the International Muography Workshop 2024 held in Santa Fe, New Mexico, USA.

Test of photomultiplier tubes for the Muon Detectors of the Large High Altitude Air Shower Observatory

We present recently developed portable muon tracking detectors based on robust and modern technology for imaging applications. Muon Portable Imager for Counter-terrorism (MuPIC) exploits triangular plastic scintillator bars with wavelength-shifting fiber optics along with silicon photomultipliers to improve detector performance over conventional photomultiplier technology. The muon detection efficiency was measured to be 85%, and the average position resolution is 2.52 mm for a given detector configuration. Improvements to light collection efficiency through double-sided readout of the scintillator bars decouple the detector performance from position dependence, in contrast with previous muon tomography detectors developed in Canada. The compact design of the MuPIC detector hardware directly enables field deployment with minimal complexity. We demonstrate the flexibility of the MuPIC detector through both scattering and attenuation tomography experiments.

Abstract We present the construction and validation of a low‐cost muon detector in Paraguay, located at the center of the South Atlantic Magnetic Anomaly (SAMA), where the geomagnetic cutoff rigidity is 9.63 GV. The detector consists of plastic scintillator plates coupled with silicon photomultipliers for light detection. To verify its performance, we measured the average muon flux rate and investigated its correlation with geomagnetic activity, particularly the disturbance storm time (Dst) index, during the May and October 2024 Forbush Decrease events. Using the Truncated Time‐Shift test—a recent statistical method for comparing time‐series—we found a strong correlation, indicating our detector reliably measures the muon flux over time. Our measurements also allowed us to resolve the detailed morphology of the Forbush decreases, by comparison with local magnetic field fluctuations. These initial results represent a step forward in ground‐level radiation monitoring within the SAMA, and highlight the potential of economical muon detectors as components of early‐stage diagnostic systems for space weather forecasting.

Renewable energy dependence on variable weather creates mismatches with energy demand. One possible solution is to produce and store green hydrogen by energy surpluses for later use. While surface storage options are limited, subsurface storage in salt caverns (200 m to 2 km deep) is more suitable due to their favorable properties. However, imaging these caverns is difficult because traditional geophysical methods often lack the resolution or depth penetration needed, making it challenging to study such formations effectively. Many of the limitations of conventional geophysical prospecting methods can be addressed by Muon Radiography (MR), an advanced technique that uses cosmic muons to detect underground density variations. Because muons penetrate deeply, their attenuation reveals information about the density and structure of the material, allowing for the identification of cavities with high spatial resolution over several hundred meters. This article presents a MR project aimed at imaging and characterizing underground salt caverns in southern Sicily. A muon detector was first installed at the surface to collect a calibration sample of free-sky muons, then moved to an underground gallery at -106 m ASL to test the method near a known tunnel. The paper includes expected results from synthetic data and first data analysis from the calibration and underground samples.

The CosmicWatch Desktop Muon Detector (v3X) is a compact, low-cost, and portable device designed for detecting ionizing radiation, including cosmic-ray muons. Building on previous iterations, the v3X introduces significant hardware and firmware improvements that enhance sensitivity, usability, and data acquisition capabilities. The detector integrates a plastic scintillator and silicon photomultiplier (SiPM), custom designed electronics for signal processing, onboard data storage, OLED display, environmental sensors, and USB connectivity. With a total component cost under $100 and a build time suitable for high school students, the v3X is ideal for education, outreach, and introductory research applications in particle and astroparticle physics. This paper details the design, performance, and potential use cases of the v3X, supported by example measurements demonstrating its functionality.

Precise muon detection with novel micropattern gaseous detectors

To assess the viability of a shallow-depth neutrino detector, a Cosmic Muon Veto Detector (CMVD) is being constructed on top of the stack of Resistive Plate Chamber (RPC) detectors at TIFR, Mumbai. The CMVD employs extruded plastic scintillators for muon detection, with wavelength-shifting fibers coupled to silicon photomultipliers (SiPMs) for signal readout. A highly stable, low-noise power source is essential for biasing the SiPMs, as the precision, accuracy, and stability of the supply directly impact the consistency of their gain. To address this, we designed a biasing power supply capable of delivering 50–58 V in 50 mV steps, with a maximum short-circuit current output of 1 mA. The system incorporates digital voltage control, stabilization, and current monitoring, making it compatible with external controllers (such as microcontrollers). This added flexibility and modularity allow for additional functionalities, including temperature compensation. Designed to supply multiple SiPMs with close to breakdown voltages in parallel, the circuit seamlessly integrates with the front-end electronics of the detector system.

As the multidisciplinary applications of cosmic-ray muons expand to large-scale and wide-area scenarios, the construction of cosmic-ray muon detector arrays has become a key solution to overcome the hardware limitations of an individual detector. For muography, the array-based detector design enables fast-scanning of large target objects, allowing for the rapid identification of density variation regions, which can improve the efficiency of tomography. This paper integrates scintillator detector technology with Internet of things technology, proposing a novel array networking model for nationwide deployment. The model enables long-distance data collection and distribution, laying the foundation for future multidisciplinary applications, such as muography and other fields.

Muon detection technology is an innovative type of geophysical exploration method that uses the penetrating ability of cosmic ray muons to detect and image the internal density structure of targets, offering the advantage of non-destructive detection. However, the applied research on muon detection technology is still in its initial stage, with research gaps existing in aspects such as the selection of optimal field observation parameters for muon detection instruments and muon inversion theory. To improve observation efficiency, this paper studies how to select optimal observation parameters in muon detection technology and proposes a method for selecting optimal observation parameters based on FreeCAD modeling and the energy attenuation formula of muon rays after penetrating matter. Additionally, a density-length product calculation method based on the muon survival rate formula is established, using the muon survival rate formula to reflect muon flux attenuation and thereby perform density inversion of objects. For the first time, muon imaging technology is applied to the detection of the No. 2 Mausoleum of the XiXia Imperial Tombs, verifying that muon imaging technology can effectively identify density anomalies inside the mausoleum tower, providing key data support for the structural analysis and protection of the XiXia Imperial Tombs. This paper systematically studies muon observation and inversion theories, laying a foundation for relevant researchers conducting muon detection work in the future.

CUPID will be a next-generation experiment searching for neutrinoless double beta decay in the inverted mass ordering regime. The reduction of backgrounds in the region of interest is critical to the performance of the experiment. Despite its underground location, muon-induced events will be a non-negligible source of background for CUPID, and their mitigation will be critical in reaching CUPID's target sensitivity. This mitigation will be achieved with a muon veto system, which must fit within the physical constraints of the existing infrastructure while maximizing geometrical coverage. We present the design, construction, and characterization of prototypes for a modular system of plastic scintillator panels with embedded plastic wavelength-shifting fibers connected to silicon photomultipliers for the CUPID muon veto. The 100 × 50 × 2.5 cm3 panel prototype presented here exhibited a light yield of (55.9 ± 1.5) p.e./MeV with a position reconstruction resolution of 25 × 25 cm2. This design also achieves a muon detection efficiency of (98 ± 1)%. We compare the light yield, uniformity, and position reconstruction potential of different prototype designs.

High latitude observation of the Forbush decrease during the May 2024 solar storms with muon and neutron detectors on Svalbard

Reliable cosmic-ray measurements require a thorough understanding of the detector used. It is especially important when detectors are very simple like the scintillator detectors considered in this work, which provide only information about the amplitude of the signal generated by a detected particle. Arrays of these devices can work in coincidental setups to detect Extensive Air Showers caused by high-energy primary cosmic rays. Due to their low cost and simple design, they can be used as elements of large detector networks needed for the search for global correlations in the cosmic rays. To be able to interpret data collected by those arrays, extensive simulations of such detectors are necessary to determine their efficiency of detection of different types of particles. This work presents the results of analysis of such simulations performed using the Geant4 software (v1.1.2). The analysis results lead to the conclusion that detectors feature almost maximal (close to 100%) efficiency for the detection of cosmic-ray muons and electrons with momenta greater than 0.03 GeV/c. Their sensitivity to low-energy electrons and photons is lower but not negligible and has to be properly taken into account during the interpretation of collected data.

Abstract Observations of temporary Forbush decreases (FDs) in the Galactic cosmic-ray (GCR) flux due to the passage of solar storms are useful for space-weather studies and alerts. Here, we introduce techniques that use global networks of ground-based neutron monitors and muon detectors to measure variations of GCR rigidity spectra in space during FDs by (1) fitting count rate decreases for power-law rigidity spectra in space with anisotropy up to second order and (2) using the “leader fraction” derived from a single neutron monitor. We demonstrate that both provide consistent results for hourly spectral index variations for five major FDs, and they agree with daily space-based data when available from the Alpha Magnetic Spectrometer. We have also made the neutron monitor leader fraction publicly available in real time. This work verifies that ground-based observations can be used to precisely monitor GCR spectral variation over a wide range of rigidities during space-weather events, with results in real time or from short-term postanalysis.

The Link System of resistive plate chambers (RPC) within the CMS Muon detector is being upgraded as part of CMS upgrade phase-2, aimed at optimising performance for the high luminosity LHC (HL-LHC) environment. This upgrade employs new electronics to improve Muon hit timing resolution and handle higher data rates. Key components of the upgraded system are the link boards and control boards. For the phase-2 upgrade, 1,592 boards need to be produced. The production is divided into two phases, pilot production and full production, to secure the quality of the entire production. This paper outlines a three-step production test plan for the pilot production of the Link System. This test plan ensures quality and functionality by performing primary quality control, basic electronics tests, and advanced system performance testing sequentially. Each step is subject to strict quality control and requires approval before proceeding. This structured approach optimizes error detection and resolution, leading to accurate and reliable results and ensuring that the upgraded system meets the operational requirements of the HL-LHC.

Correlated errors may devastate quantum error corrections that are necessary for the realization of fault-tolerant quantum computation. Recent experiments with superconducting qubits indicate that they can arise from quasiparticle (QP) bursts induced by cosmic-ray muons and γ-rays. Here, we use charge-parity jump and bit flip for monitoring QP bursts and two muon detectors in the dilution refrigerator for detecting muon events. We directly observe QP bursts leading to correlated errors that are induced solely by muons and separate the contributions of muons and γ-rays. We further investigate the dynamical process of QP burst and the impact of QP trapping on correlated errors and particle detection. The proposed method, which monitors multiqubit simultaneous charge-parity jumps, has high sensitivity to QP bursts and may find applications for the detection of cosmic-ray particles, low-mass dark matter, and far-infrared photons.

The high-penetration cosmic-ray muons can be used for scanning and exploring the structure of large geological formations, up to several hundred meters of thickness. Since the attenuation of the muon flux as it passes through the object depends on the density of the rock mass being scanned, measurements with high resolution muon detectors (muography) in suitable arrangement allow reconstruction of three-dimensional density distribution (muon tomography). The estimated density distributions can be used to infer the geological structure of the screened rock mass if the density inhomogeneity reflects it. The muographic method is extremely efficient because the mapping is performed along approximately straight lines, similar to X-ray or CT scans, since the deflection of high-energy muon trajectory due to interaction with the rock material is almost negligible. This ensures that density inhomogeneities can be determined with much sharper contours and higher accuracy than with other geophysical methods. In this paper we present a muography based high precision identification of a fractured zones and cavities which explorations are challenging to surface geophysical methods. The applicability of muon tomography is demonstrated in an area which is built up by Mesozoic carbonates (Buda Hills, Hármashatárhegy Range in Hungary) with variable topography, where the dominant directions and trends of the fault systems and fracture network are well known, which allows the tomographic results to be controlled. This case study demonstrates that muographic method is capable to obtain an accurate 3D picture of the density anomalous fracture system in carbonates for a rock thickness up to 100 m, that can very useful and unique contribution to geological interpretation and geological model building.

This study explores how atmospheric pressure affects muon detection rates. By analyzing data from six Cosmic Watch detectors, we organized the collected information, examined the correlation between atmospheric pressure and muon detection rates, and addressed the timing discrepancies across detectors. Our findings show that muon detection rates decrease as atmospheric pressure rises. The study also improves time difference correction methods, providing new strategies and tools for detecting rare coincidence events recorded by multiple detectors.

Abstract As a kind of widely existed cosmic ray particles, muons have strong penetrativity to water layer and rock layer, which is suitable for anti-interference navigation and positioning at underwater depth of one hundred meters, and its positioning ability in the environments such as strong electromagnetic suppression and electromagnetic silence can become a new type of auxiliary means for underwater positioning. This paper summarizes the latest progress of muometric navigation technology, introduces its generation mechanism and basic physical properties, reviews the research results of domestic and foreign research in muon detection and localization, analyzes the principle and key technology of its underwater navigation and localization, looks forward to the future direction of the research and technological breakthroughs, and discusses the prospects for its application in underwater navigation and the challenges it faces.