Deep Underground Research Articles

How beliefs about tampering with nature influence support for enhanced geothermal systems: A cross-national study.

Many believe that enhanced geothermal systems (EGS) can greatly increase the extraction of geothermal energy worldwide, helping to decarbonize heat and electricity production. Effective communication is key to realizing the potential of EGS, yet we currently know little about how the public perceives this emerging technology. This exploratory study contributes to the literature with a cross-national survey in the United States (n=1003) and Switzerland (n=1028), two countries with active EGS projects. Specifically, we explore how EGS support relates to beliefs about the deep underground and perceptions of EGS as tampering with nature. The results show that respondents tend to perceive the deep underground as part of nature, dangerous, and unpredictable. The majority are positive about using the deep underground as a resource, although there were variations regarding specific underground activities. In both countries, EGS support is greater for respondents who perceive the underground as something for human use, perceive more benefits than risks from EGS, and support their country's transition to renewable energy. In Switzerland, EGS support is positively related to trust in industry developers and negatively related to perceptions that EGS is tampering with nature. The results offer novel theoretical insights into perceptions of the deep underground in relation to energy development. From a practical standpoint, the results suggest that those seeking to develop EGS may want to consider how to familiarize individuals with current subsurface energy activities, including efforts to protect the underground from unwanted consequences of "tampering," alongside engaging in discussions about the risks and benefits of EGS.

Deep Underground Earthquake Observation: Small to Moderate Earthquakes and Microearthquakes Identification

Deep Underground Earthquake Observation: Small to Moderate Earthquakes and Microearthquakes Identification

Synergy between DUNE and T2HKK to probe invisible neutrino decay

We address the consequence of invisible neutrino decay within the framework of two long base-line neutrino experiments: T2HKK (Tokai-to-Hyper-Kamiokande-to-Korea) and DUNE (Deep Underground Neutrino experiment). Our primary objective is to bring out the aspects of CC (charged current) and NC (neutral current) measurements at DUNE in the context of invisible neutrino decay. We find that the inclusion of NC measurements with the CC measurements enhances its ability to constrain invisible neutrino decay. Further, the synergy between DUNE and T2HKK improves the constraints on invisible neutrino decay. At 3σ C.L. (confidence level) the derived constraint is τ3/m3 ≥ 6.21 × 10−11 s/eV. Additionally, if nature prefers ν3 to be unstable and the decay width is τ3/m3 = 2.2 × 10−11 s/eV, this combination can exclude the no-decay scenario at more than 5σ C.L. Although the CP sensitivity is not much hindered in the presence of invisible neutrino decay, the measurements of θ23 and the ability to resolve octant of θ23 is significantly influenced in these individual experiments. In the presence of invisible neutrino decay, the synergy between DUNE and T2HKK can exclude the wrong octant somewhat more effectively than either experiment alone.

Stress Characteristics and Mechanical Behavior of Rock Masses with an Opening under Complex Deep Underground Stress Conditions

In this study, the impact of principal stress states on the stress characteristics and initial failure of the rock mass surrounding a three-center arch opening was investigated using complex variable function methods and Discrete Element Method (DEM) numerical modeling. First, the mapping function of the opening was determined using the trigonometric interpolation method, and the influence of the number of terms in the mapping function on its accuracy was revealed. Based on this, the far-field stress state of the underground rock mass was characterized by the ratio of the minimum to maximum principal stress (λ) and the angle (β) between the principal stress and the vertical direction. This stress state was then converted into normal and shear stresses. Using complex variable function theory, the stress characteristics at the boundary of the opening under different stress states were analyzed. Finally, DEM numerical modeling was employed to study the initial failure characteristics at the boundary of the opening and its relationship with the stress distribution. The results indicate that the lateral pressure coefficient significantly affects the stability of the opening by influencing stress concentration around the surrounding rock. Low lateral pressure coefficients lead to tensile stress concentration at the boundary perpendicular to the maximum principal stress. As the coefficient increases, tensile stress decreases, and compressive stress areas expand. While the principal stress direction has a minor effect on stress concentration, it notably impacts stress distribution at the boundary. When λ < 1.0 and β = 45°, stress distribution asymmetry is most pronounced, with the highest compressive stress. The early failure distribution aligns with stress concentration areas, validating the use of stress analysis in predicting opening stability and failure characteristics.

Technological Novelties and Scientific Discoveries with the Borexino Experiment

The Borexino experiment has developed, in its 32 years of activity, techniques and methods that allow for unprecedented radiopurity levels, which continue to be the current state of the art. These pioneering techniques and methods represent a new standard for ultra-low-background physics, a legacy that Borexino leaves to future experiments studying low-energy neutrinos and searching for rare events with detectors operating deep underground. The Borexino experiment leaves an equally influential scientific legacy with its discoveries and precise measurements of the nuclear processes that cause the Sun and stars to shine. Thanks to its unparalleled low background in the energy window of ∼150 keV to ∼15 MeV, the Borexino experiment also has contributed significantly to the understanding of neutrino oscillations with the observation of the energy-dependent matter to vacuum-dominated flavor conversion probability of solar neutrinos. Along with this textbook-quality body of solar neutrino results, the Borexino experiment has contributed to the study of the Earth's mantle radioactivity with background-free measurements of geoneutrinos. This article presents an overview of the long-lasting Borexino results and of the experimental efforts required to achieve them.

지하공간에서 건설 공사를 위한 법제 고찰

The necessity for construction projects in underground spaces is gradually increasing. Currently, since there is no special law governing underground spaces, the Civil Code is applied. However, the Civil Code does not present a legal concept for underground spaces or deep strata. Therefore, there has been ongoing debate on whether the effect of land ownership under the Civil Code is recognized or excluded in deep strata. The “Deep Strata Act (Draft)” proposed in September 2020 mainly stipulates that when constructing or managing transportation facilities in deep strata, it is permissible to use the deep strata underground, and in such cases, compensation for the land as prescribed by the “Land Compensation Act” is not required, nor is it necessary to establish a separate superficies under the Civil Code. This premise implies that ownership rights do not extend below the boundary depth. However, simply limiting private ownership rights for public projects could lead to essential infringements on property rights, which necessitates considering the relationship between ownership and superficies under the Civil Code, as well as compensation for losses, when enacting special laws. Particularly, unlike the Japanese Civil Code, Article 212 of the Korean Civil Code includes an abstract provision of “legitimate interest,” making it difficult to adopt the Japanese Deep Strata Act as is. Under the current legal system, construction projects in deep strata require individual assessments of the scope of ownership, as well as the establishment of separate superficies and compensation for losses. Nevertheless, for the efficiency of construction projects in deep strata, it is believed that not only the enactment of special laws but also a legal review of the Civil Code and other legal principles is necessary.

Artificial Intelligence Models for Predicting Ground Vibrations in Deep Underground Mines to Ensure the Safety of Their Surroundings

Ground vibrations induced by underground mining blasting has a significant impact on the stability and safety of surface buildings near mines. Due to the thick rock layers overlying underground mines, there is presently limited accuracy in regard to predicting ground vibrations induced by underground mine blasting. Therefore, this study aims to improve the accuracy of predicting ground vibrations induced by underground blasting by comprehensively measuring the peak particle velocity (PPV) in all three directions and independently considering on the impact of vertical distance. Random forest regression (RFR), bagging regression (BR), and gradient boosting regression (GBR) were used to regress the X-axis PPV (X-PPV), Y-axis PPV (Y-PPV), and Z-axis PPV (Z-PPV) based on blasting records measured at an iron mine. In addition, a genetic algorithm, gray wolf optimizer (GWO), and a particle swarm optimization were used to optimize the parameters of the RFR, BR, and GBR. The comparison results show that GWO-GBR is the optimal model for the prediction of the X-PPV (R2 = 0.8072), Y-PPV (R2 = 0.9147), and Z-PPV (R2 = 0.9265), respectively. Thus, the GWO-GBR model proposed in this study is considered a highly reliable model for predicting ground vibrations induced by underground mine blasting to ensure the safety of the mines’ surroundings.

Key principles of stress control method

Underground excavation would cause two main excavation effects: (1) stress redistribution, including radial stress decrease and tangential stress concentration; and (2) surrounding rock degradation. Comprehensive consideration of excavation effects is crucial to prevent underground engineering disasters. However, the two excavation effects are not considered in the predominantly used Platts pressure arch theory, whereas the New Austrian tunneling method is focused on the full utilization of the strength of the surrounding rock. Construction designing using these methods could lead to disaster deep underground. Thus, in this study, the stress control method (SCM) was proposed to comprehensively consider the two excavation effects. The following two key SCM principles were introduced in this study: (1) adopt the largest possible prestressing force to increase the low radial stress caused by excavation; (2) timing of support should be as early as possible to minimize surrounding rock deterioration. The application principles of SCM in hard rock tunnels and soft rock tunnels are explained

Static friction testing of various materials in liquid nitrogen

The Deep Underground Neutrino Experiment will utilize charge readout planes (CRPs) that are submerged within liquid argon. These charge readout planes are part of a drift detector used measure the cascade of charged particles generated by the interaction of neutrinos with the argon nuclei. The CRPs require specially designed supports to ensure they remain precisely positioned even after the thermal contraction of the sensors and the cryostat that occurs during cooldown. These supports must also protect the cryostat floor and CRPs from potential damage due to thermal strain during cooldown. These objectives are satisfied by utilizing an intermediate slip plane within the support to provide a stress relief point with a lower friction coefficient than the interface between the sensor support and the cryostat floor. Therefore, the design of these supports requires knowledge of the static coefficient of friction for various materials at cryogenic temperatures. It was found that the coefficient of friction associated with materials such as metals, ceramics, and polymers have been studied very little at cryogenic temperatures. Specifically, there is not much data relative to the static coefficient of friction associated with polymers at low temperatures. Therefore, a test apparatus was developed to measure various materials’ cryogenic static coefficient of friction with the geometry required for the support design. Several tests with different materials were carried out using this test apparatus to identify a material combination with very different static coefficients of friction that can be used for the membrane to support interface and intermediate slip plane.

Protection and Utilization of Historical Sites Using Digital Twins

Historical sites are incomplete relics left by human activities and are also valuable resources for human society, with most of them buried deep underground. Because the protection of original historical sites is difficult, very few sites choose this method. Many funerary objects that have been in historical sites are scattered in museums, losing their original context and complicating their utilization. Thus, using digital technology to protect and utilize historical sites and to explore their outstanding value from historical, aesthetic, and anthropological perspectives is a foremost concern. Therefore, this study aims to develop a comprehensive method for the protection and utilization of historical sites, that is, digital protection and utilization based on a digital twin. We constructed a historical site digital twin model using qualitative and vertical methods, including a physical entity, virtual entity, twin data center, digital twin service, and connection. We also established a technical framework of data acquisition and processing, digital protection, and digital utilization, forming a layered management and application of digital resources. In digital protection, information in the real world and the virtual world are connected to monitor risks, collect data, create simulations, and propose protection strategies, quickly and accurately. In digital utilization, the knowledge graph is constructed to associate seemingly unrelated information, explore potential knowledge, and improve information sharing. In addition, the method is validated by means of case studies of historical sites in China. In this paper, the historical sites of the Northern Qi Dynasty in Taiyuan, Shanxi, especially the Xuxianxiu Tomb and Lourui Tomb, are discussed in detail. The results indicate that this method is effective for the protection and utilization of historical sites.

NOx Emission Prediction of Diesel Vehicles in Deep Underground Mines Using Ensemble Methods

The mining industry faces persistent challenges related to hazardous gas emissions. Diesel engine-powered wheeled vehicles are commonly used during work shifts and are a primary source of nitrogen oxides (NOx) in underground mines. Despite diesel engine manufacturers providing gas generation data, mining companies need to predict NOx emissions from numerous load-haul-dumping (LHD) vehicles operating under dynamic conditions and not always equipped with gas sensors. This study focused on two ensemble methods: bootstrap aggregation (bagging) and least-square boosting (boosting) to predict NOx emissions. These approaches combine multiple weaker statistical models to yield a robust result. The innovation of this research is in the statistical analysis and selection of LHD vehicles’ working parameters, which are most suitable for NOx emission prediction; development of the procedure of source data cleaning and processing, model building and analyzing factors, which may influence the accuracy; and the comparison of two ensemble methods and showing their advantages and limitations for this specific engineering application, which was not previously reported in the literature. For datasets obtained from the same LHD vehicle and different operators, the more efficient bagging method gave a coefficient of determination R2 > 0.79 and the RMSE (root mean square error) was under 30 ppm, which is comparable with the measurement accuracy for transient regimes of physical NOx sensors available in the market. The obtained insights can be utilized as input for mine ventilation systems, enhancing mining transport management, reducing workplace air pollution, improving work planning, and enhancing personnel safety.

Artificial Lift: 25 Years of Change Tracked in the Pages of JPT

Nodding donkeys. Thirsty birds. Rocking horses. All are playful nicknames for the oil and gas icon known as a pumpjack. To the uninformed, the pumpjack is a thing-a-ma-jig that has something to do with oil, probably “fracking” because that’s what drilling rigs do, right? But as an industry-educated and well-informed reader of JPT, you know this is inaccurate. By whatever name you call it, you know that the pumpjack is the visible manifestation of an invisible physics equation, a mechanism buried deep underground that lifts reservoir fluids to the surface. You also know it is one type of artificial lift available in a stable of systems with equally curious and technical names like progressive cavity, plunger, jet, gas lift, and electrical submersible pump (ESP). While there is no global repository of artificial lift statistics, industry observers estimate that 90 to 95% of the world’s producing wells use artificial lift, as noted in a 2013 JPT story on the challenges and opportunities for artificial lift. Artificial lift, as applied in oil and gas production, has existed for over 100 years. A 2014 JPT story laid out a brief history of the practice, sharing how the walking beam principle dates back to at least 476 CE when used in Egypt, and evidence of the use of sucker rods to lift fluids has been excavated from the homes of wealthier families in the early days of the Roman Empire. Even as we leap forward to the modern-day application of artificial lift systems, many techniques and technologies resemble their original designs. How these systems are applied has changed, especially in the past decade-plus with the emergence of shale. As highlighted in a JPT story on the past 25 years of technology advances, the industry underwent a robust era of technology development in its rush to crack the shale development riddle. Since 1999, the industry also delivered a 36% increase in global supplies, as noted in this JPT story celebrating this industry’s biggest innovations. 1999 represents an interesting turning point in the industry’s technological journey. Also, it is the last time JPT editors took the opportunity to celebrate the publication as it turned 50 years old that year. What follows are a few highlights from JPT’s coverage of advances and changes made in artificial lift applications and practices over the past quarter century.

Cosmogenic background simulations for neutrinoless double beta decay with the DARWIN observatory at various underground sites

Xenon dual-phase time projections chambers (TPCs) have proven to be a successful technology in studying physical phenomena that require low-background conditions. With 40t\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$40\\,\ extrm{t}$$\\end{document} of liquid xenon (LXe) in the TPC baseline design, DARWIN will have a high sensitivity for the detection of particle dark matter, neutrinoless double beta decay (0νββ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$0\\upnu \\upbeta \\upbeta $$\\end{document}), and axion-like particles (ALPs). Although cosmic muons are a source of background that cannot be entirely eliminated, they may be greatly diminished by placing the detector deep underground. In this study, we used Monte Carlo simulations to model the cosmogenic background expected for the DARWIN observatory at four underground laboratories: Laboratori Nazionali del Gran Sasso (LNGS), Sanford Underground Research Facility (SURF), Laboratoire Souterrain de Modane (LSM) and SNOLAB. We present here the results of simulations performed to determine the production rate of 137\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${}^{137}$$\\end{document}Xe, the most crucial isotope in the search for 0νββ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$0\\upnu \\upbeta \\upbeta $$\\end{document} of 136\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${}^{136}$$\\end{document}Xe. Additionally, we explore the contribution that other muon-induced spallation products, such as other unstable xenon isotopes and tritium, may have on the cosmogenic background.

A multiangle polarised imaging-based method for thin sectionsegmentation.

The most crucial task of petroleum geology is to explore oil and gas reservoirs in the deep underground. As one of the analysis techniques in petroleum geological research, rock thin sectionidentification method includes particle segmentation, which is one of the key steps. A conventional sandstone thin sectionimage typically contains hundreds of mineral particles with blurred boundaries and complex microstructures inside the particles. Moreover, the complex lithology and low porosity of tight sandstone make traditional image segmentation methods unsuitable for solving the complex thin sectionsegmentation problems. This paper combines petrology and image processing technologies. First, polarised sequence images are aligned, and then the images are transformed to the HSV colour space to extract pores. Second, particles are extracted according to their extinction characteristics. Last, a concavity and corner detection matching method is used to process the extracted particles, thereby completing the segmentation of sandstone thin sectionimages. The experimental results show that our proposed method can more accurately fit the boundaries of mineral particles in sandstone images than existing image segmentation methods. Additionally, when applied in actual production scenarios, our method exhibits excellent performance, greatly improving thin sectionidentification efficiency and significantly assisting experts inidentification.

Clarification of generation mechanism of volatilization flux based on detailed analysis of transport phenomena near the ground surface and quantitative evaluation of influencing factors

Assessing human health risks associated with inhalation exposure of volatile chemical substances (VCSs) volatilized from contaminated soil requires quantitative evaluation of volatilization fluxes (VFs) and an understanding of how environmental factors impact VF generation. We developed a numerical model that considers advection-dispersion and VCSs volatilization in unsaturated soil, enabling VF prediction through parameter optimization using soil column tests. We conducted parametric analyses to assess how key parameters, such as soil particle size, contamination depth, temperature, and surface soil thickness affect VF generation. By analyzing VCS transport near the ground surface, we uncovered the mechanisms underlying VF generation. We also identified characteristic differences in VF generation behavior linked to soil particle size and gas saturation at the ground surface. Under specific soil particle size conditions, significant VF generation occurred even when contamination was deep underground. This was primarily observed when capillary effect was pronounced, and VCSs continued to be supplied to the ground surface through upward advection. Considering the significant impact of VF generation on human health, our parametric study provides valuable insights into relationships between different parameters and VF behavior, especially under varying ground surface temperatures and surface soil thicknesses. This study contributes to developing effective remediation and risk-reduction strategies. Environmental ImplicationThis research examines the environmental implications of volatile chemical substances (VCSs), including hazardous materials like benzene and trichloroethylene, in contaminated soil. VCSs pose health risks when they volatilize from soil. The study quantifies volatilization fluxes (VF) and elucidates the environmental factors affecting VF generation. These findings are vital for effective environmental management. By comprehending the mechanisms governing VF generation, particularly regarding soil properties like particle size, this research enhances the effectiveness of soil contamination remediation and risk reduction. It emphasizes the essential need for a comprehensive VCS assessment in contaminated soils to protect both human health and the environment.

Two-phase interaction in isothermal hydro-mechanical-chemical coupling for improved carbon geological sequestration modelling

ABSTRACT Geological sequestration is an established method to store carbon deep underground. Many studies have proposed coupled constitutive models that can simulate such a complicated process; however, the coupling effect of multi-phase fluid flow and transport of chemical solutes in the liquid phase remains to be investigated. This study presents a multi-phase non-reactive hydro-mechanical-chemical constitutive framework under isothermal conditions based on mixture coupling theory. Non-equilibrium thermodynamics is used to generate an entropy production equation, and phenomenological equations use this to derive the chemical transport and interaction between two-phase fluid flows. This study proposes novel terms in the final governing equations. The model results are in good agreement with the results of a benchmark experiment and those found in the literature; the model has been used to compare the behaviour of carbon dioxide in the gas and supercritical phases. Sensitivity analysis was conducted to determine the effect of the parameters in the new terms. Sensitivity analysis revealed the significant impact of relative permeability and saturation values on the new terms, emphasising the importance of understanding frictional behaviour in porous media for accurate fluid flow modelling and prediction. This study urges further experimentation and model refinement to improve carbon sequestration modelling in larger formations.

Sub-background radiation exposure at the LNGS underground laboratory: dosimetric characterization of the external and underground facilities

Radiobiological studies conducted in Deep Underground Laboratories allow to improve the knowledge of the biological effects induced by ionizing radiation at low doses/dose rates. At the Gran Sasso National Laboratory of the Italian Institute of Nuclear Physics we can study the possible differences in behavior between parallel biological systems, one maintained in a Reference-Radiation Environment (RRE, external) and the other maintained in an extremely Low-Radiation Environment (LRE, underground), in the absence of pressure changes, the RRE and LRE laboratories being at the same altitude. For these investigations, it is mandatory to evaluate the dose rate values at RRE and LRE. The aim of our work is to provide a comprehensive dosimetric analysis for external and underground laboratories. Measurements of the different low Linear Energy Transfer (LET) components at RRE and LRE were performed using different detectors. Gamma dose rates were 31 nSv/h at RRE and 27 nSv/h at LRE respectively. The muon dose rate was 47 nSv/h at RRE and negligible at LRE (less than pGy/h). Dosimetric measurements were also carried out to characterize the devices used to modulate the gamma dose rate, namely, a gamma source irradiator (to increase the dose rate by about 90 nSv/h) and shields (of iron at LRE and lead at RRE). Using the iron shield at LRE a dose reduction factor of about 20, compared to the RRE, was obtained for the low LET components; inside the lead shield at RRE the gamma component was negligible compared to the muonic component. Radon activity concentrations were approximately of 20 Bq/m3 at both LRE and RRE. The intrinsic contribution of radioactivity in the experimental set up was of 0.25 nGy/h, as evaluated with a GEANT4-simulation, using as input the measured activity concentrations. GEANT4 simulations were also performed to calculate the neutron dose rate at RRE, yielding a value of 1.4 nGy/h, much larger than that at LRE (which is less than pGy/h). In conclusion, RRE and LRE are currently characterized and equipped to perform radiobiological studies aimed at understanding the involvement of the different low LET components in determining the response of biological systems.

Overview of DISCOVER22 experiment in the framework of INFN-LNGS Cosmic Silence activity: challenges and improvements in underground radiobiology

One of the most intriguing and still pending questions in radiobiology is to understand whether and how natural environmental background radiation has shaped Life over millions of years of evolution on Earth. Deep Underground Laboratories (DULs) represent the ideal below-background exposure facilities where to address such a question. Among the few worldwide DULs, INFN-Laboratorio Nazionale del Gran Sasso (LNGS) is one of the largest in terms of size and infrastructure. Designed and built to host neutrino and dark matter experiments, since the 1990 s the LNGS has been one of the first DULs to systematically host radiobiology experiments. Here we present the DISCOVER22 (DNA Damage and Immune System Cooperation in VEry low Radiation environment 2022) experiment recently started at LNGS. DISCOVER22 aims at investigating how the low radiation background modulates the Immune System (IS) response in in vitro and in vivo models. Underground radiobiology experiments are particularly complex and tricky to design and perform. In these studies, the accurate characterization of exposure scenarios is mandatory, but a challenging aspect is to understand how the very few ionizing tracks in the ultra-Low Radiation Environment (LRE) interact with the living matter in space and time in order to trigger different biological responses. In this Perspective, we describe these challenges and how we address them through a microdosimetric and a radiobiological approaches. We aim at linking physical microdosimetric measurements and the corresponding biological radiation responses by using radiation biophysical models that could shed light on many as yet unresolved questions.

Measurement of granite resistivity under deep underground conditions based on van der Pauw method

With the growing demand for sustainable energy and infrastructure development in the country, the utilization of deep geothermal resources and the development of deep underground space engineering are becoming more and more important. Under the background that the country vigorously promotes the development of deep rock and soil underground space and the utilization of resources. The experiment will be performed on granite, one of the deep subsurface rocks, a rock type widely used in geotechnical research projects because of its high strength, low permeability and thermal stability. However, its properties under the extreme temperature and chemical conditions deep in the earth are unknown, and how to efficiently convert deep rocks into geothermal resources for utilization is still unknown. Therefore, studying the influence of temperature and chemical corrosion on the resistivity of granite is very important to ensure the safety and durability of underground structures and effectively utilize thermal energy resources in deep underground. This experiment will control the influence of temperature, pressure, chemical corrosion and the comprehensive effect of the three on the resistivity of granite, and indirectly measure the amount of heat absorbed in the granite rock mass. Simulate the deep underground granite under high confining pressure, high ground temperature and corrosion conditions the nature of the performance. Record, count and analyze the data, comprehensively judge the environmental interference of the granite rock formation under actual conditions and compare the destructive effects of temperature and chemical corrosion and the change of the resistivity of the rock mass. Help scientifically judge and accurately analyze the underground construction problems that may be encountered in future projects and the effective utilization of geothermal energy and provide a basis for the application of key technologies and methods.

Muon energy reconstruction for applications in neutrino astronomy in the DUNE far detector

DUNE (Deep Underground Neutrino Experiment) is a proposed long-baseline neutrino oscillation experiment located in the United States. The main physics objectives of DUNE are to measure neutrino oscillations and interactions, search for nucleon decay, observe supernova neutrino bursts and beyond Standard Model (BSM) effects. The DUNE far detector will be located 4850 feet underground at the Sanford Underground Research Facility in Lead, South Dakota. It will house the world's largest liquid-argon time projection chambers (TPC). The DUNE far detector can detect high-energy leptons that arise from interactions of cosmogenic neutrinos and search for neutrinos originating from the decay of weakly-interactive massive particles (WIMPs) annihilations occurring inside the Sun. Selecting upward-going muons reduces the background from cosmic-ray muons. The muon energy is estimated from the electromagnetic showers accompanying the muon, a technique that allows energy reconstruction up to a few hundred TeV.