Geant4 Advanced Course 2025 @ CERN

3 Nov 2025, 14:00 → 7 Nov 2025, 19:40 Europe/Zurich

593/R-010 - Salle 11 (CERN)

              

Tutorial on Geant4 for users interested to improve their understanding and usage of Geant4. Appropriate for creating intermediate and advanced applications in any domain, with emphasis on topics most relevant to experiments in High Energy or Nuclear Physics. This is a tutorial course based on Geant4 version 11.3.

Lectures will cover intermediate and advanced features of Geant4 starting from the basic building blocks covered in the beginners course, interspersed with discussion sessions.

The course is expected to be of interest to users with intermediate experience in Geant4 and familiarity with the toolkit. Participants are expected to have a reasonable knowledge of C++.

The course will be held in hybrid form, with both participation in person (limited) and online using Zoom (unlimited). A link to join will been provided to participants. Participation in person will require additional formalities to enter the CERN site. 

Lectures will start at 14:00 CET (Central European Time), which is 13:00 UTC (Universal Time).  The planned end time is to 18:00 CET.

 

Pre-requisites: 

• Basic knowledge of the C++ language 
• Basic knowledge of MC simulation techniques
• Overview and knowledge of the Geant4 simulation toolkit, such as that obtained following the Geant4 beginners course or equivalent knowledge
• Intermediate experience in using the Geant4 simulation toolkit, from developing a new application using Geant4 or modifying an existing Geant4 application.

Objectives: 

• Acquire deeper understanding of particle transport Monte Carlo
• Acquire additional knowledge and experience in using the Geant4 simulation toolkit

 

NOTE:  Registration is now CLOSED.

 

Monday 3 November

1 Welcome and Practicalities

• Welcome to the course
• Practical aspects - Zoom, Mattermost, Questions, ...

Speaker: John Apostolakis (CERN)

2 Overview

• An overview of the topics covered in the course - and how they fit

Speaker: John Apostolakis (CERN)

Overview-G4AdvancedCourse2025-v2.pdf

3 Geometry - Part 1

• Recall: what are solids(shapes), logical & physical volumes
• Introduction to the types of physical volumes: simple (Placements), and 'complex' ones (Replicated and Parameterised)
• Replicas
• Parameterised Volumes
• Divisions volumes
• Touchables and Nested parameterisations

Speakers: Dr Gabriele Cosmo (CERN), John Apostolakis (CERN)

geometry-advanced-I-2025.pdf

15:20 Break

4 Physics: particles and processes

• Particles
• Ions
• Processes
• What happens at a step
• Order of initialisation and execution
• Cuts
• How to prepare custom particle and process

Speaker: Vladimir Ivantchenko (CERN)

PartProcesses2025.pdf

5 Hadronic Physics - I

Introduction (what is it, why we need it, what are the challenges)
Overview of the hadronic physics framework
Hadronic cross-sections
Hadronic final-state models
Hadronic data libraries

Speaker: Alberto Ribon (CERN)

HadronicPhysics1.pdf

6 Definition of UI commands

• G4UIExecutive
• Definition of custom UI commands

Speaker: Makoto Asai

DefinitionOfUICommands.pdf

Recording

Tuesday 4 November

7 Magnetic Field

• Magnetic field
• Field integration and other types of field
• Steppers & Interpolation

Speaker: John Apostolakis (CERN)

MagneticField-G4Adv25-v1.pdf

8 Electromagnetic physics

• Energy loss
• Cuts per region
• Models per region
• Atomic de-excitation
• Multiple and single scattering
• Documentation for electromagnetic physics

Speaker: Vladimir Ivantchenko (CERN)

EMPhysics1-2025.pdf

15:25 Break

9 Questions and/or Homework from Day 1

Questions from exercises / topics of Day 1

10 Multithreading - Part 1

• Why use multi-threading in Geant4
• What data is shared between threads
• User commands to control threading and regular and error output
• User code / actions in multi-threaded (MT) mode

Speaker: John Apostolakis (CERN)

MultiThreading-G4Adv25-v2.pdf

11 Additional User classes

• User limits
• User information classes
• Stack management

Speaker: Makoto Asai

Recording

UserClasses.pdf

12 Discussion

Magnetic & other fields, EM physics, Multi-threading, User Classes

Speaker: John Apostolakis (CERN)

Wednesday 5 November

13 Fast Simulation

• Fast parameterised simulation
• G4VFastSimulationModel
• G4FastSimulationManagerProcess
• Use of "Ghost" volumes
• Techniques of fast simulation

Speakers: Alberto Ribon (CERN), Anna Zaborowska (CERN)

fastSim_G4advancedTuto.pdf

Recording

14 Hadronics physics II

• Pre-compound and de-excitation models
• Intra-nuclear cascade models (Bertini, Binary, Liege (INCL))
• String models (Fritiof, Quark Gluon String)
• Capture/stopping models
• Fission models
• Elastic process
• Neutron physics
• Ion physics

Speaker: Alberto Ribon (CERN)

HadronicPhysics2.pdf

15:20 Break

15 Hadronic Physics II (continued)

16 Geometry - Part 2

• Geometrical regions
• Geometry optimization
• Parallel geometries
• Moving geometries
• CAD interface
• Tips & Tricks

Speakers: Dr Gabriele Cosmo (CERN), John Apostolakis (CERN)

geometry-advanced-II-2025.pdf

Recording

17 Scoring

• Introduction to Scoring
• Command-based scoring
• Sensitive detector vs. primitive scorer
• Basic structure of detector sensitivity
• Sensitive detectors and hits

Speaker: Makoto Asai

Scoring.pdf

18 Discussion on UI, user actions and scoring

• UI commands
• User actions
• Scoring

Speaker: Makoto Asai (Jefferson Lab (USA))

Thursday 6 November

19 Electromagnetic physics II - Optical Photons

Optical photons - generation, propagation and their physics processes

Speaker: Alexander Howard (Imperial College (GB))

AH_OpticalPhotons_G4advanced_v2025.pdf

20 Discussion

Your (further questions) about
- EM Physics II (photons)
- User Action classes

21 Homework / questions from Day 3

15:20 Break

22 Multi-threading - Part 2

Topics:
• The challenge of MT : thread safety
• Reading input file in multithreaded mode
• Initialising ‘optimization’ voxels in parallel

Speaker: John Apostolakis (CERN)

Multithreading-part2-2025.pdf

Recording

23 Questions & Answers - your topics

Friday 7 November

24 Physics Lists

• Introduction to Physics Lists
• The Geant4 Physics List interface
• Using pre-packaged physics lists
• How to choose a physics list
• Examples

Speakers: Alberto Ribon (CERN), Gunter Folger

PhysicsLists.pdf

25 Physics Biasing

Physics biasing techniques

Speaker: Alberto Ribon (CERN)

PhysicsBiasing.pdf

15:00 Break

26 Event Biasing

• Introduction
• Early Provided Biasing Options
• Primary Particle Biasing
• Options In Hadronic
• Geometry-based importance biasing
• Weight Window Technique
• User defined biasing
• Reverse Monte-Carlo
• Generic Biasing Scheme

Speaker: Marc Verderi (Centre National de la Recherche Scientifique (FR))

event-biasing.pdf

27 Homework / questions from Day 4

28 Questions & Answers

General discussion
Answers on topics raised on Mattermost

17:10 Adjourn