Simulation and Modelling of Non- Destructive Testing Methods Utilising Cosmic Ray Muon Flux Craig Stone HMS Sultan Nuclear Department

Build a Geant4 workspace Create/Adapt model for a nuclear reactor Implement Geant4 and related packages Modify Geant4 to work with OpenScientist package An example output image form the Geant4 programme taken from CosmicRays.com Project Aims Create Working Scintillator setup!

Non-destructive testing Process by which Structures (e.g. Pipe work and the reactor cores) can be Analysed, looking for: – Circuitry Deposits; blocking water flow – Faults in the material; nucleating cracks..without damaging them Previously preformed using other similar techniques: – Ultrasound – Terrahertz imaging – Magnetic/fluorescent Particle Inspection Examples of NDT in practice.

Problems with performing NDT on a reactor core. – Risk of Radiation – Some techniques have limited effectiveness – Access to the core limited by the RPV Solution – Utilise cosmic particle flux – No access to core needed – No radiation hazard – Passive: No work done on the core or inside the RPV Non-destructive testing A Closed System must be maintained.

Preface – Important Physics Elementary Particles – Lepton Tertiary particle in Cosmic radiation times mass of an Electron MeV/c^2 Move at 99.98% Speed of Light – Relativistic Due to Relativistic Effects decay takes 110 μS Makes it down 30 km – Reaches sea level Highly Penetrating – Scattered less easily. Muons

Cosmic rays - Production of Muons Muon production from Neutrino interaction Muon penetrates cloud chamber. Feynman diagrams of muon production/decay

Cosmic Rays – Characteristics Primary Protons Accelerated by EM force Secondary Mostly comprised of Muons, towards sea- level. Other secondary and tertiary particles exist. Most don’t reach us or do not interact. Muon Energies range form GeV Flux -Cos 2 (θ) Most Particles Enter From Above

Previous Research

Geant4 Geant4 (for GEometry ANd Tracking) is a platform for "the simulation of the passage of particles through matter," using Monte Carlo methods. It is the successor of the GEANT series of software toolkits developed by CERN, and the first to use Object oriented programming (in C++). ~Wikipedia, accessed 12 th Jan ‘10

How Geant4 Works C++ code holds physics information Monte carlo cycle, –Checks processes; Decay, interaction etc. –Declares hits, interactions or decays to the other source files –Draws Particle to an image file/writes data files (optional) Repeated for the next Monte Carlo cycle Geant4 Several Models used at CERN –BaBar and GLAST at SLAC –ATLAS, CMS and LHCb at LHC, CERN –Borexino at Gran Sasso Laboratory –MINOS at Fermilab –EXO One model previously used by Supervisor Several Novice, Extended and Advanced examples Included in software package.

Existing Models Models the Core of a nuclear Submarine Reactor. Assumes Muons Enter top-down through the core. Particles coloured by charge only. Uses a ‘Particle gun’ Complex method of simulating trajectories Particle Gun also determines particle energy. Red tracks show negative particles, Green shows Neutral particles. Positive particles show as blue tracks, more on this later. Muons Gamma Muon or electron? More Muons

New Model - Geometry & Particle Source Assumed Tomography focuses on a pipe, filled with CRUD (Chalk river unidentified deposits) and water. Various models explore shielding and pipe contents. Uses GPS (General Particle Source); Different Trajectories and Energies can be run from a simple macro file. Crud alters the scattering angle of the muons. If the scatter this can be detected, so can the crud. General Particle Source; approximation of a particle shower

Neutron Incident muons Something Positive

Applications in industry Double scintillators above and below the sample. Particle takes ‘random walk’ though scintillators and material Particle is deflected Scintillators Detect the incident angle, and final angle. Computer Model draws trajectory Scatter angle for selected volume recorded. Model of Pipe built up over successive hits. Material within the pipe can be determined from scatter angle Voxel Image of Scatter Angle Pipe

Where next - New models and analysis New Models – Modifying existing model; recreate reactor core. – Adding Scintilators – Implementing a Multithreaded version of Geant4 – Magnetic Lensing OpenScientist – Analysis programme, which produces: – Histogrammes – Plots – Voxel images.

Acknowledgements Thanks to… – Dr Ian Giles, funding. – Dr Paul Jeneson, Samantha Morris, Sean Jarman, Ross McCart and the other members of staff at HMS Sultan. – Dr Paul Snow, University of Bath. Any Questions?