Simulation and Modelling of Non-Destructive Testing Methods Utilising Cosmic Ray Muon Flux

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

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

3. 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.

4. Non-destructive testing • 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 A Closed System must be maintained.

5. Preface – Important Physics Muons • Elementary Particles – Lepton • Tertiary particle in Cosmic radiation • 206.8 times mass of an Electron - 105.7 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.

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

7. 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 10-100 GeV • Flux -Cos2(θ) Most Particles Enter From Above

8. Previous Research

9. 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 12th Jan ‘10

10. Geant4 • 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 • 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.

11. Muons Muon or electron? More Muons 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. Gamma Red tracks show negative particles, Green shows Neutral particles. Positive particles show as blue tracks, more on this later.

12. New Model - Geometry & Particle Source General Particle Source; approximation of a particle shower • 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.

13. Incident muons Neutron Something Positive

14. 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 Pipe Voxel Image of Scatter Angle

15. 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.

16. 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?