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?