Papers by Maxime Lagrange
arXiv (Cornell University), May 16, 2024
In cultural heritage conservation, it is increasingly common to rely on non-destructive imaging m... more In cultural heritage conservation, it is increasingly common to rely on non-destructive imaging methods based on the absorption or scattering of photons (X or γ rays) or neutrons. However, physical and practical issues limit these techniques: their penetration depth may be insufficient for large and dense objects, they require transporting the objects of interest to dedicated laboratories, artificial radiation is hazardous and may induce activation in the material under study. Muons are elementary particles abundantly and freely produced in cosmic-ray interactions in the atmosphere. Their absorption and scattering in matter are characteristically dependent on the density and elemental composition of the material that they traverse, which offers the possibility of exploiting them for subsurface remote imaging. This novel technique, nicknamed "muography", has been applied in use cases ranging from geophysics to archaeology to nuclear safety, but it has been so far under-explored for a vast category of cultural heritage objects that are relatively large (from decimeters to human size) and dense (stone, metals). The development of portable muon detectors makes muography particularly competitive in cases where the items to be analysed are not transportable, or set up in a confined environment. This document reviews the relevant literature, presents some exemplary use cases, and critically assesses the strengths and weaknesses of muography in this context.
Dataset for the challenge at the 2nd MODE workshop on differentiable programming 2022
Zenodo (CERN European Organization for Nuclear Research), Jul 20, 2022
The TOMOPT software is a tool to optimize the geometrical layout and specifications of detectors ... more The TOMOPT software is a tool to optimize the geometrical layout and specifications of detectors designed for muon scattering tomography. Based on differentiable programming techniques, TOMOPT consists in a modular pipeline that models all the aspects of a muon tomography task, from the generation and interaction of cosmic ray muons with a parameterized detector and passive material, to the inference of the volume properties. This enables the optimization of the detector parameters via gradient descent, to suggest optimal detector configurations and specifications. This optimization is subjected to various external constraints such as cost, logistics, and material identification efficiency.
The SilentBorder project aims to develop and construct a new high-technology scanner for the iden... more The SilentBorder project aims to develop and construct a new high-technology scanner for the identification of hazardous and illegal goods hidden in trucks and sea containers. The scanner will enable scanning of shipping containers or cargo and is based on muon tomography, a technology that uses natural cosmic ray muons and therefore is inherently safe for people. We report on the development of a simulation and reconstruction framework aimed at optimizing the geometry of the detector and exploring feasibility of CRT in real smuggling scenarios using simulated data. The framework includes GEANT4 modeling of light transport in a scintillating fiber tracker to optimize the geometry and materials used to produce fiber mats. A systematic comparison was made of particle generators such as CRY, MUSIBO, and EcoMug interfaced with the GEANT4 toolkit to find the most effective one for modeling real smuggling scenarios. The Point-of-Closest-Approach reconstruction algorithm was used to create 3D images of sea containers or trucks. An analysis of the sensitivity of CRT was performed using simulated synthetic data generated for different smuggling scenarios of contraband of low-Z organic materials and high-Z inorganic materials. Results of our research indicate that by using muon tomography, it would be possible to improve the performance and sensitivity of sea container and cargo screening systems to overcome limitations of traditional screening methods, such as X-ray scanners, when it comes to detecting illicit materials that may be well concealed. CRT can provide a complementary imaging technique that could enhance the detection capabilities of existing systems.
arXiv (Cornell University), Sep 24, 2023
We describe a software package, TomOpt, developed to optimise the geometrical layout and specific... more We describe a software package, TomOpt, developed to optimise the geometrical layout and specifications of detectors designed for tomography by scattering of cosmic-ray muons. The software exploits differentiable programming for the modeling of muon interactions with detectors and scanned volumes, the inference of volume properties, and the optimisation cycle performing the loss minimisation. In doing so, we provide the first demonstration of end-to-end-differentiable and inference-aware optimisation of particle physics instruments. We study the performance of the software on a relevant benchmark scenario and discuss its potential applications. Our code is available on Github [1]
arXiv (Cornell University), Sep 14, 2023
Non-destructive subsurface imaging methods based on the absorption or scattering of photons or ne... more Non-destructive subsurface imaging methods based on the absorption or scattering of photons or neutrons are becoming increasingly popular in cultural asset conservation. However, these techniques are limited by physical and practical issues: their penetration depth may be insufficient for large items, and they usually necessitate transferring the objects of interest to specialised laboratories. The latter issue is recently being addressed by the development of portable sources, but artificial radiation can be harmful and is thus subjected to strict regulation. Muons are elementary particles that are abundantly and freely created in the atmosphere by cosmic-ray interactions. Their absorption and scattering in matter are respectively dependent on the density and elemental composition of the substance they traverse, suggesting that they could be used for subsurface remote imaging. This novel technique, dubbed "muography," has been used in applications ranging from geophysics to archaeology, but has remained largely unexplored for a wide range of cultural heritage objects that are small by muography standards but whose size and density are too large for conventional imaging methods. This document outlines the general arguments and some early simulation studies that aim at exploring the low-size limit of muography and its relevance for cultural heritage preservation.
Toward the end-to-end optimization of particle physics instruments with differentiable programming
Reviews in Physics, Jun 1, 2023
TomOpt: Differentiable Muon-Tomography Optimization
<p> </p><p>We ... more <p> </p><p>We propose to employ differentiable programming techniques in order to construct a modular pipeline that models all the aspects of a muon tomography task, from the generation and interaction of cosmic ray muons with a parameterized detector and passive material, to the inference on the atomic number of the passive volume.</p><p>This enables the optimization of the detector parameters via gradient descent, to suggest optimal detector configurations, geometries, and specifications, subject to external constraints such as cost, detector size, and exposure time.</p><p>The eventual aim is to release the package open-source, to be used to guide the design of futur detectors for muon scattering and absorption imaging.</p>
Exploiting Differentiable Programming for the End-to-end Optimization of Detectors
HAL (Le Centre pour la Communication Scientifique Directe), May 31, 2023
arXiv (Cornell University), Mar 22, 2022
Reviews in Physics
The full optimization of the design and operation of instruments whose functioning relies on the ... more The full optimization of the design and operation of instruments whose functioning relies on the interaction of radiation with matter is a superhuman task, given the large dimensionality of the space of possible choices for geometry, detection technology, materials, data-acquisition, and informationextraction techniques, and the interdependence of the related parameters. On the other hand, massive potential gains in performance over standard, "experience-driven" layouts are in principle within our reach if an objective function fully aligned with the final goals of the instrument is maximized by means of a systematic search of the configuration space. The stochastic nature of the involved quantum processes make the modeling of these systems an intractable problem from a classical statistics point of view, yet the construction of a fully differentiable pipeline and the use of deep learning techniques may allow the simultaneous optimization of all design parameters. In this document we lay down our plans for the design of a modular and versatile modeling tool for the end-to-end optimization of complex instruments for particle physics experiments as well as industrial and medical applications that share the detection of radiation as their basic ingredient. We consider a selected set of use cases to highlight the specific needs of different applications.
Instruments
A key task for customs workers is the interception of hazardous, illegal and counterfeit items in... more A key task for customs workers is the interception of hazardous, illegal and counterfeit items in order to protect the health and safety of citizens. However, it is estimated that only a small fraction of cargo is inspected and an even smaller fraction of trafficked goods are detected. Today, the most widely used technology for scanning vehicles, ranging from vans and trucks to railcars, is γ ray and X-ray radiography. New technologies are required to overcome current technological shortcomings, such as the inability to detect the target material composition, the usage of harmful ionising radiation sources and the resultant low throughput. Cosmic ray tomography (CRT) is a promising technology for cargo screening. Cosmic ray muons have average energies of around 10,000 times larger than a typical X-ray and therefore can penetrate relatively large and dense materials. By analysing muon scattering, it is possible to identify materials hidden inside shielding that is too thick or deep f...
TomOpt: Differentiable Muon-Tomography Optimization
<p> </p><p>We ... more <p> </p><p>We propose to employ differentiable programming techniques in order to construct a modular pipeline that models all the aspects of a muon tomography task, from the generation and interaction of cosmic ray muons with a parameterized detector and passive material, to the inference on the atomic number of the passive volume.</p><p>This enables the optimization of the detector parameters via gradient descent, to suggest optimal detector configurations, geometries, and specifications, subject to external constraints such as cost, detector size, and exposure time.</p><p>The eventual aim is to release the package open-source, to be used to guide the design of futur detectors for muon scattering and absorption imaging.</p>
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Papers by Maxime Lagrange