impressions from mc2005 j. apostolakis g. folger

Impressions from MC2005

J. ApostolakisG. Folger

Talk overview

• The conference• The radiation Transport tools ‘present’• Applications• Themes and topical issues

Conference overview• About 200 participants: providers, users, ..• Organisation

– Plenaries on MC tools– Parallel sessions on

• Methods & data advancements (electron/gamma, neutron, hadron)

• Verification & computer implementation• Applications in particular areas

– Reactor, medical including dosimetry, ..

• Wide diversity– Several session in parallel– This summary is a personal viewpoint

• And relies on notes, as talk presentations not yet available

Codes / Tools / ToolkitSeveral teams present:• MCNP 5• MCNPX• FLUKA• GEANT4• PHITS‘Missing’• EGS (nrc/5)• Penelope • Tripoli• MARS• …

Different ‘philosophies’• MCNP 5/X, FLUKA

– Standard ‘tool’/code driven by input files

– Built-in ‘tallies’ chosen by flags

– ‘Flat’ geometries• Delineated by surfaces

– Yet more physics options being made available

• Geant4– Toolkit– Hierarchial geometry, …

MCNP5• Neutrons, , , protons, ..• Long line of codes (60s to now) • From Los Alamos National

Laboratory– Team of 12 code developers & 4

on data– Funding from ASCI program

• Capability evolution• Great emphasis on Quality

Assurance– Revised implementation in F90

• Profit from large supercomputer facility

– Especially for validation

Traditional strengths, include• Neutron treatment using data

– For E <~ 150 MeV• Variance reduction techniquesLatest improvements• Push for proton radiography

– Extend protons up to 50 GeV• New intra-nuclear cascade as

option – INCL4 (Liege)

• New data– ENDF/B-VII

• Built-in parallelization– MPI and OpenMP

• Generating weights fast– With PARTISN code

MCNPX• Is eXtended version of MCNP4C

– Transports 34 particle types up to TeV energies

• Uses – evaluated data libraries (p, n, -

nuclear) – Physics models where libraries

are not available– Option for crossover at 20MeV, or

as needed (some data up to 150MeV)

• Written in F90• Many options for radiation tallies,

biasing– Weight window generator– Options for sources– Pulse-height (with variance

reduction) & coincidence tallies

• Physics enhancements– CEM 2K and INCL4 (cascade), in

addition to older Bertini, HETC, Fluka, Isabel models

doppler broadening – nuclear models

• Awards for bug reports– ‘certificate’ and $$

• Support NAG/IBM/Intel f90 complr• Parallel computation

– For all particles (uses MPI)– High speedup for criticality

calculations• Future plans

– Magnetic fields– Delayed neutrons & g– CAD input with spline tracking

7-Can HEU Test Problem

Air

HEU

Aluminum

~5% Enriched

PHITS

• Simulate – hadron-neucleus with

E up to 200 GeV– Nucleus-nucleus from

10 MeV/n to 100 GeV/nucleon

– Transport heavy ions, hadrons & leptons

• Neutrons down to 10-5 eV

• Features – JQMD for nucleus-

nucleus using molecular dynamics

– JAM hadronic cascade– Photons, electrons

and low-energy neutrons as in MCNP4C.

From RIST, Japan

FLUKATool known at CERN – so just a few remarks• Compare to data for -scopic data only• ‘Not a toolkit’

– Physics models are fully integrated– Self-consistent: full cross-talk between EM, hadronics, neutrons

(with effort for same level of accuracy)– Correlations preserved enabling predictivity– ‘No programming is necessary’

• Recent extensions for heavy ions• Numerous comparisons & applications

– Including CERF, TARC, ATLAS, Atmosphere, AMS, Borexino– Talks on E deposition in LHC magnets, , CERF comparisons

Geant4

• One plenary and over 12 parallel talks• Much interest

– Applications– Methods

• Some concerns from users– Many choices available – Difficulty to get going without good guidance

Summary - Codes

• Fewer codes represented– Missing MVP, MCP, MCBEND, TRIPOLI, EGS, ITS,

VIM, TART, …• More complex questions

– Burn-up, activation• Remove bridge between MC and depletion codes

– Correlated sources and tallies– (Anti)coincidence of events across multiple regions– Moving geometry, stochastic geometry– 2 & 3 D graphical output necessary

Selected topics

CAD inputH. Tsige-Tamirat

Forschungszentrum Karlsruhe• Input from STEP/IGES files

– Thinned with engineer’s help• Tool to read CAD file, process

& create MCNP input file– Uses open source CAD as

toolkit for reading– Addresses overlaps and gaps

(‘voids’)– Created in C++, using MVC

• Status– Working for realistic JET

example

• Other efforts underway– Delegating navigation to CAD

system (speed issues)– Tesselating BREP solids

From *Summary talk*• GUIs are becoming popular• CAD is making progress

– Tools to convert to solids start to appear

– Still need to achieve arbitrary surface spline NURBS

– Would like to see these tools become OpenSource

Human phantoms

Distributions centers

• Codes primarily available from– Radiation Safety Information Computational

Center (RSICC) http://rsicc.ornl.gov/ at Oak Ridge National Laboratory (ORNL).

– OECD / NEA (European Nuclear Energy Agency) http://www.nea.fr/ Nuclear Data Bank computer program services http://www.nea.fr/html/dbprog/

• Conditions for distributions are evolving– Personal licenses (not site as in past)

Applications

• Significant interest in medical applications– Dedicated session on ‘Tomographic Models

for Radiation Protection dosimetry’• Reactor applications

– Several sessions – Emerging applications for Accelerator Driven

• Space applications• Much interest in CAD-input

Other notable / novel

• Intercomparisons of ‘tools’ at times MCNP, Geant4, Fluka, data– For proton therapy applications– For accelerator driven applications

• Novel approach to MC– Using Field Programmable Gate Arrays

• for Ultra-high Speed Monte Carlo Computation– A.S.Pasciak, J.R.Ford.

Unusual applications

• Enhanced electron and photon fluxes in thunderstorms– T. Torii (JNDI), T.

Sugita (SSL), T. Nishijima, Z.-I. Kawasaki (Osaka U) Japan

Simulation of the Generation of EM Shower by Muon Irradiation　　　　　　　　　　　　　　　　　　　　　

μ ＋（２ GeV)

Emission of massive knock-on electrons

μ- （２ GeV)

Elevation Angle: 30°, Number of HistoriesElevation Angle: 30°, Number of Histories ：： 55E-FieldE-Field ： ： Winter Thundercloud (Tri-pole)Winter Thundercloud (Tri-pole)

Deposition energy Deposition energy in the atmosphere in the atmosphere is calculated by is calculated by using Geant4 using Geant4 code.code.

Muon beam

thundercloud

Other topics from the Conference Summary Comments

Summary- Data/libraries

• More users produce their own data• Need better QA of data• Little evidence of effort on emerging needs

– Delayed gamma, neutron– Improved secondary particle production

including correlations• Library repository, with graphics good idea

– NADS: //nuclear/llnl.gov/CNP/nads

Summary – Physics & Methods

• New physics models continue to emerge– Users getting frustrated with too wide choices– Provide recommendations

• Methods improvements– Variance reduction with pulse-height tallies– Some tough issues remain

• Effort to speed up– Parallelism, some re-write code for this– Algorithm efficiency

Summary - Applications• About 25% of talks• Codes need to provide results & errors

– Users need “convergence score card”– Normality checks, 2nd moment of analysis, trends

• Users training more of an issue– Codes have 100-1000 options– Users unaware of “easy” solutions

• Application work should begin with related benchmark simulation– Eliminate time consuming mistakes

Summary - Benchmarks

• Not enough benchmark papers– Perhaps most important aspect of MC development

• Need way to gather results– Web site to post papers

• Mix “component” benchmarks with integral– Integral result can mask offsetting errors/deficiencies (

e.g. Geant4)• Develop quantitative metric for comparisons

– Standard toolkit good start, some concern as well