Simulation and Modelling of Non-Destructive Testing Methods Utilising
Cosmic Ray Muon Flux
Craig StoneHMS 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
• 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.
Muons
Cosmic rays - Production of MuonsMuon 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 10-100 GeV
•Flux -Cos2(θ)
Most Particles Enter From Above
Previous Research
Geant4Geant4 (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
• 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.
AcknowledgementsThanks 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?