Monte Carlo

Mary PW Chin 钱碧慧博士
PhD (Wales), MSc (Surrey)
Here are my dirty hands at work, mostly on Monte Carlo simulations — using different codes — for various applications. Different codes: FLUKA, MCNP, EGSnrc, PENELOPE and GEANT4. Various applications, medical and non-medical, including facility, bunker and detector designs, dosimetric and shielding studies.
my dirty hands at work

Monte Carlo from scratch

Monte Carlo from scratch
☞ slideshow

FLUKA tutorial

tutorial: a gentle introduction to FLUKA
☞ slideshow

FTREE: my baby


Spallation neutron facilities


Positron emission tomography (PET)

Boron neutron capture therapy (BNCT)

Anthropomorphic phantoms

Event-by-event simulations

Bunker design & shielding

Grid & cluster computing

Conventional photon therapy

The making of

☞ Publications
☞ Google Scholar

☞ PhD
Monte Carlo portal dosimetry
☞ MSc
Neutron contamination in a radiotherapy maze


FTREE is an interactive catalogue of complete radiation cascades. It is a creative use of Monte Carlo simulations. Simulations are intercepted to access instantaneous values of the desired attributes before they get over-written as the simulation progress. Interceptions are passive; none modifies the physics or transport in any way. Rigorous post-processing spins out the awesome family trees. FTREE is not a Monte Carlo radiation transport code. Thus named, with F for FLUKA, and TREE in honour of the most enduring DOS command.

Beginning from a single particle impinging matter, each progeny is tracked under real-life irradiation conditions until it is fully absorbed or goes below preset energy thresholds. The ensuing radiation field is characterised interaction by interaction, accounting for nth secondaries producing (n+1)th secondaries, recursively, in a full inventory from upstream all the way downstream. Each progeny is uniquely differentiated into a family tree, indented by the nth generation of the particle, rooting from the single source particle as the first foreparent. The kinship, no less complicated than real life, between each particle is uniquely identified without ambiguity. This mode of scientific observation, analysis and presentation goes beyond:

FTREE also offers a unique opportunity to observe rare events far out in the Gaussian tail which would have been washed out by averaging; such are the events less probable, but no less correct in physics compared to highly probable events populating the Gaussian peak.

The idea for FTREE was first conceived at a workshop, where the maiden work, Carbon stories in calcium, was presented. This was followed by some early developments:

Later, at the International Nuclear Chemistry Congress in Brazil, FTREE found herself a novel experiment technique as much as a novel teaching resource. The reference paper is here: Single-history Monte Carlo analysis for radiation detection and measurement 2015 J Radioanal Nucl Chem.

Snapshot from CERN: the horizontal n_TOF tunnel
tracks from the horizontal n_TOF tunnel
The vertical (new) n_TOF beamline
tracks from the vertical n_TOF beamline
480 MeV proton on tungsten: the bold
tracks from a proton-on-tungsten spallation neutron source
480 MeV proton on tungsten: the beautiful
tracks from a proton-on-tungsten spallation neutron source
Carbon therapy of a human brain
tracks from carbon therapy of a virtual human brain
Nuclear data processing: NJOY, PREPRO

Processing of incident neutron sub-library from ENDF/B VII.1, JENDL 4.0 and JEFF 3.1.1
13th Int Conf Nuclear Reaction Mechanisms
CERN-Proceedings-2012-002 2012 Varenna

ND2010: Nuclear Data for Science & Technology 2010 Jeju Island
show (pdf 3.7M)       paper (pdf 384k)

Spallation neutron facilities

A brief radiation history of the future Ultra Cold Neutron source at TRIUMF
4th International Nuclear Chemistry Congress 2014 Maresias
show (pdf 3.3M)

Perturbation of phase space downstream by parameters upstream
10th SATIF (Task Force on Shielding Aspects of Accelerators, Targets & Irradiation Facilities) 2010 Geneva
show (pdf 2.2M)

Proton and neutron penetration of candidate target materials for the European Spallation Source
10th ICANS (International Collaboration on Advanced Neutron Sources) Meeting 2010 Grindelwald
show (pdf 1.6M)

Preliminary formulation of a nuclear data roadmap for designing the ESS
EFNUDAT (European Facilities for Nuclear Data Measurements) Workshop 2009, Budapest
show (pdf 819k)

Energy deposition by doughnut beams bombarding a (p,xn) target
T Am Nucl Soc 2010 103 40
show (pdf 1.5M)

Neutronic considerations in designing the European Spallation Source (ESS)
T Am Nucl Soc 2009 101 102
show (pdf 1M)


Candidate therapeutic ions: a physics account of interactions in and escapes out of the body
Radiother Oncol 2012 102 S157
show (pdf 2.3M) as presented at ICTR-PHE 2012 Feb Geneva

Sample Histories from Carbon Therapy of a Human Brain
T Am Nucl Soc 2011 105 55
show (pdf 1.2M)

Filtering exit photons for treatment monitoring of carbon therapy
FLUKA Collaboration Meeting 4 July 2011 Milano

Carbon stories in calcium
1st FLUKA Advanced Course & Workshop 2010 Ericeira
show (pdf 2.4M)

Positron emission tomography (PET)

Monte Carlo investigation of positron annihilation in medical positron emission tomography
Nucl Instrum Meth A 2007 580 1 484
show (pdf 1.9M)

Three-quanta positron annihilation in blood samples of different oxygenation levels
T Am Nucl Soc 2008 99 55
show (pdf 782k)

Boron neutron capture therapy (BNCT)

A detailed Monte Carlo accounting of radiation transport in the brain during BNCT
Appl Radiat Isot 2009 67 7-8 Suppl 164
show (pdf 451k)

Monitoring of gamma emission and neutron transmission during boron neutron capture treatment delivery
J Radioanal Nucl Chem 2009 281 1 149

Anthropomorphic phantoms

Definition by radiation properties: a proposal for next-generation anthropomorphic phantoms
T Am Nucl Soc 2009 100 43
show (pdf 635k)

Anthropomorphic voxel phantoms: beyond organ shapes and sizes
T Am Nucl Soc 2008 99 65
show (717k)

Event-by-event Monte Carlo simulations

Event-by-event Monte Carlo tracking of neutron-nucleus collisions in neutron detectors
T Am Nucl Soc 2007 97 288
show (pdf 1M)

Non-convergence of Geant4 hadronic models for 10 and 30MeV protons in 18O and 14N
Appl Radiat Isot 2009 67 3 406

EGSnrc and GEANT4 simulation of electron nanosteps in gold
T Am Nucl Soc 2008 99 70

Bunker design & shielding

An evaluation of current recommendations on high-energy radiotherapy accelerator shielding
T Am Nucl Soc 2007 97 265
show (pdf 606k)

Neutron contamination in a radiotherapy maze
MSc Dissertation & story 1999 University of Surrey

Grid & cluster computing

An embarrassingly parallel framework for running EGSnrc/BEAMnrc/DOSXYZnrc, FLUKA, MCNP/MCNPX, GEANT4 and PENELOPE on grid and cluster computers
15th Int Conf Use of Computers in Radiation Therapy 2007 Toronto (Novotel Digital) ed. Bissonnette J University of Toronto 93-97
paper (pdf 164k)       show (111k)

Implementation of BEAMnrc Monte Carlo simulations on the Grid
14th Int Conf Use of Computers in Radiation Therapy 2004 Seoul ed Yi BY(Jeong Publishing)

Grid and cluster computing for radiotherapy
Scientific Computing 2006 March 27-31
article (pdf 328k)

My activities as NGS user since April 2004
3rd UK National Grid Service User Forum 2007 Oxford
show (pdf 418k)

Conventional photon therapy

Correction for dose-response variations in a scanning liquid ion chamber EPID as a function of linac gantry angle
Phys Med Biol 2004 49 8 N93

Monte Carlo simulation of portal dosimetry on a rectilinear voxel geometry: a variable gantry angle solution
Phys Med Biol 2003 48 16 N231

Monte Carlo portal dosimetry
Med Phys 2007 32 3228

A Monte Carlo solution for external beam photon radiotherapy verification
The Monte Carlo Method: Versatility Unbounded in a Dynamic Computing World 2005 Chattanooga (American Nuclear Society)
paper (pdf 238k)

Monte Carlo portal dosimetry
PhD story & thesis 2005 University of Wales

The making of my dirty hands at workThe pair of hands near the top of this webpage: both hands are really mine. My right hand, which had a fracture when I was thrown off the horse like a projectile back in September 2010. We were enjoying a beautiful walk on a wonderful day when she broke into an unplanned gallop. I took the X-ray images and superimposed my bones over my favourite textile using GIMP — a fantastic open-source alternative to Photoshop.