Optimizing geophysical muon radiography using information theory

SUMMARY Cosmic ray muons are highly penetrating, with some reaching several kilometres into solid rock. Consequently, muon detectors have been used to probe the interiors of large geological structures, by observing how the muon flux varies with direction of arrival. There is an increasing need to discriminate between materials differing only slightly in bulk density. A particularly demanding application is in monitoring underground reservoirs used for CO2 capture and storage, where bulk density changes of approximately 1 per cent are anticipated. Muon arrival is a random process, and it is the underlying expectation values, not the actual muon counts, which provide information on the physical parameters of the system. It is therefore necessary to distinguish between differences in muon counts due to real geological features, and those arising from random error. This is crucial in the low-contrast case, where the method can reach the information theoretic limit of what a data source can reveal, even in principle. To this end, methods to analyse information availability in low-contrast muon radiography have been developed, as have means to optimally interpret the available data, both for radiography and for tomography. This includes a method for calculating expectation values of muon flux for a given geological model directly, complementing existing Monte Carlo techniques. A case study, using a model of carbon capture is presented. It is shown that the new data analysis techniques have the potential to approximately double the effective sensitivity of the detectors.

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Applications of muon absorption radiography to the fields of archaeology and civil engineering

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2018.0057 ◽

2018 ◽

Vol 377 (2137) ◽

pp. 20180057 ◽

Cited By ~ 2

Author(s):

G. Saracino ◽

F. Ambrosino ◽

L. Bonechi ◽

L. Cimmino ◽

R. D'Alessandro ◽

...

Keyword(s):

Cosmic Rays ◽

Density Distribution ◽

Physical Process ◽

Civil Engineering ◽

Imaging Technique ◽

Mass Density ◽

Cosmic Ray ◽

Muon Flux ◽

Particle Detector ◽

Muon Radiography

Muon radiography, also known as muography, is an imaging technique that provides information on the mass density distribution inside large objects. Muons are naturally produced in the interactions of cosmic rays in the Earth's atmosphere. The physical process exploited by muography is the attenuation of the muon flux, that depends on the thickness and density of matter that muons cross in the course of their trajectory. A particle detector with tracking capability allows the measurement of the muons flux as a function of the muon direction. The comparison of the measured muon flux with the expected one gives information on the distribution of the density of matter, in particular, on the presence of cavities. In this article, the measurement performed at Mt. Echia in Naples (Saracino 2017 Sci. Rep. 7 , 1181. ( doi:10.1038/s41598-017-01277-3 )), will be discussed as a practical example of the possible application of muography in archaeology and civil engineering. This article is part of the Theo Murphy meeting issue ‘Cosmic-ray muography’.

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MLSD-OSEM reconstruction algorithm for cosmic ray muon radiography

10.1117/12.769803 ◽

2008 ◽

Cited By ~ 2

Author(s):

Yuanyuan Liu ◽

Ziran Zhao ◽

Zhiqiang Chen ◽

Li Zhang ◽

Yuxiang Xing

Keyword(s):

Cosmic Ray ◽

Reconstruction Algorithm ◽

Muon Radiography

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Bedrock sculpting under an active alpine glacier revealed from cosmic-ray muon radiography

Scientific Reports ◽

10.1038/s41598-019-43527-6 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 3

Author(s):

R. Nishiyama ◽

A. Ariga ◽

T. Ariga ◽

A. Lechmann ◽

D. Mair ◽

...

Keyword(s):

Cosmic Ray ◽

Alpine Glacier ◽

Muon Radiography

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Analysis of seasonal variations of the cosmic ray muon flux and neutrons produced by muons in the LVD detector

Bulletin of the Russian Academy of Sciences Physics ◽

10.3103/s1062873811030063 ◽

2011 ◽

Vol 75 (3) ◽

pp. 427-430 ◽

Cited By ~ 4

Author(s):

N. Yu. Agafonova ◽

◽

V. V. Boyarkin ◽

V. L. Dadykin ◽

E. A. Dobrynina ◽

...

Keyword(s):

Seasonal Variations ◽

Cosmic Ray ◽

Muon Flux

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Radio and X-ray connection in radio mini-halos: Implications for hadronic models

Astronomy and Astrophysics ◽

10.1051/0004-6361/201937207 ◽

2020 ◽

Vol 640 ◽

pp. A37 ◽

Cited By ~ 2

Author(s):

A. Ignesti ◽

G. Brunetti ◽

M. Gitti ◽

S. Giacintucci

Keyword(s):

Magnetic Field ◽

Large Fraction ◽

Cosmic Ray ◽

Physical Parameters ◽

Model Parameters ◽

Relativistic Electrons ◽

X Rays ◽

X Ray ◽

Hadronic Model ◽

Radio Halos

Context. A large fraction of cool-core clusters are known to host diffuse, steep-spectrum radio sources, called radio mini-halos, in their cores. Mini-halos reveal the presence of relativistic particles on scales of hundreds of kiloparsecs, beyond the scales directly influenced by the central active galactic nucleus (AGN), but the nature of the mechanism that produces such a population of radio-emitting, relativistic electrons is still debated. It is also unclear to what extent the AGN plays a role in the formation of mini-halos by providing the seeds of the relativistic population. Aims. In this work we explore the connection between thermal and non-thermal components of the intra-cluster medium in a sample of radio mini-halos and we study the implications within the framework of a hadronic model for the origin of the emitting electrons. Methods. For the first time, we studied the thermal and non-thermal connection by carrying out a point-to-point comparison of the radio and the X-ray surface brightness in a sample of radio mini-halos. We extended the method generally applied to giant radio halos by considering the effects of a grid randomly generated through a Monte Carlo chain. Then we used the radio and X-ray correlation to constrain the physical parameters of a hadronic model and we compared the model predictions with current observations. Results. Contrary to what is generally reported in the literature for giant radio halos, we find that the mini-halos in our sample have super-linear scaling between radio and X-rays, which suggests a peaked distribution of relativistic electrons and magnetic field. We explore the consequences of our findings on models of mini-halos. We use the four mini-halos in the sample that have a roundish brightness distribution to constrain model parameters in the case of a hadronic origin of the mini-halos. Specifically, we focus on a model where cosmic rays are injected by the central AGN and they generate secondaries in the intra-cluster medium, and we assume that the role of turbulent re-acceleration is negligible. This simple model allows us to constrain the AGN cosmic ray luminosity in the range ∼1044−46 erg s−1 and the central magnetic field in the range 10–40 μG. The resulting γ-ray fluxes calculated assuming these model parameters do not violate the upper limits on γ-ray diffuse emission set by the Fermi-LAT telescope. Further studies are now required to explore the consistency of these large magnetic fields with Faraday rotation studies and to study the interplay between the secondary electrons and the intra-cluster medium turbulence.

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Muon radiography to visualise individual fuel rods in sealed casks

EPJ Nuclear Sciences & Technologies ◽

10.1051/epjn/2021010 ◽

2021 ◽

Vol 7 ◽

pp. 12

Author(s):

Thomas Braunroth ◽

Nadine Berner ◽

Florian Rowold ◽

Marc Péridis ◽

Maik Stuke

Keyword(s):

Spent Nuclear Fuel ◽

Cosmic Ray ◽

Scattering Data ◽

Pressurized Water Reactor ◽

Test Statistic ◽

Pressurized Water ◽

Fuel Rods ◽

Acceptance Criterion ◽

Muon Radiography ◽

Kolmogorov Smirnov

Cosmic-ray muons can be used for the non-destructive imaging of spent nuclear fuel in sealed dry storage casks. The scattering data of the muons after traversing provides information on the thereby penetrated materials. Based on these properties, we investigate and discuss the theoretical feasibility of detecting single missing fuel rods in a sealed cask for the first time. We perform simulations of a vertically standing generic cask model loaded with fuel assemblies from a pressurized water reactor and muon detectors placed above and below the cask. By analysing the scattering angles and applying a significance ratio based on the Kolmogorov-Smirnov test statistic we conclude that missing rods can be reliably identified in a reasonable measuring time period depending on their position in the assembly and cask, and on the angular acceptance criterion of the primary, incoming muons.

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