Simulation and Modelling of NonDestructive Testing Methods Utilising
Cosmic Ray Muon Flux
Craig Stone
HMS Sultan
Nuclear Department
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
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.
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.
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.
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 sealevel.
•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
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
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.
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
Muon or
electron?
Gamma
More
Muons
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.
Incident muons
Neutron
Something
Positive
Applications in industry
Pipe
•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
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?