Low Energy Electromagnetic Physics

1. Low Energy Electromagnetic Physics Maria Grazia Pia, INFN Genova on behalf of the LowE WG http://www.ge.infn.it/geant4/lowE/index.html Geant4 Workshop and Geant4 D Review, CERN, October 2002

2. We have and maintain a URD regular contacts with users We have a process for requirements management but we would like to have a tool for it! OK We do analysis and design We validate our designs against use cases We do design and code reviews not enough, however… main problem: geographical spread + overwork Unit, package integration, system tests + validation we do a lot… but we would like to do more limited by availability of resources for core testing need a more systematic approach and better toolsTest & Analysis Project close collaboration with users Full requirements traceability still improving it: added documentation and validation results as traceability items in progress: traceability documentation from simple matrix to UML We hold regular WG meetings to discuss and agree our project planning We keep everything in CVS (version control) code, designs, tests, documents, papers etc. We have a SPI process with some spells of SPD sometimes… collaboration with Anaphe for a common (tailored) process We maintain a web site LowE, advanced examples, WG projects The process in a nutshell More details: see talk on Software Process in Physics, Geant4 Review 2001

3. Electron processes New parameterisations of LLNL data Various bug fixes Tests against NIST database (range) Tests against Sandia database Photon processes Rather stable Tests of angular distributions in progress Polarisation Improvement of Compton g conversion in progress Contacts with experiments for common validation tests Auger effect New Fluorescence Small fixes and improvements while re-implementing in design iteration Test beam validation in collaboration with ESA Science Payload Division PIXE Toy model Established contacts for databases, plans for new model Protons, ions Stable, minor improvements Bragg peak tests in progress Antiprotons Paper in progress, very close to submission Recent physics activities

4. Photons: mass attenuation coefficient UR 1.1 Fe Comparison against NIST data Tests by IST - Natl. Inst. for Cancer Research, Genova (F. Foppiano et al.) LowE accuracy ~ 1% Also water, Pb This test will be introduced into the Test & Analysis project for a systematic verification

5. Photon attenuation: Geant4 vs. NIST data Test and validation by IST - Natl. Inst. for Cancer Research, Genova UR 1.1 Pb water Fe • Low Energy EM • Standard EM w.r.t. NIST data accuracy within 1%

6. Photons: angular distributions UR 1.1 Rayleigh scattering: Geant4-LowE and expected distribution (more work in progress)

7. Photons, evidence of shell effects UR 1.1 Photon transmission, 1 mm Pb Photon transmission, 1 mm Al

8. Electron Bremsstrahlung UR 1.1 • New parameterisations of EEDL data library • in response to problem reports from various users • precision is now ~ 1.5 % • Plans • Systematic verification over Z and energy • Need Test & Analysis Project for automated verification

9. Electron ionisation UR 1.1 • New parameterisations of EEDL data library • in response to problem reports from various users • precision is now better than 5 % for ~ 50% of the shells, poorer for the 50% left • Plans • Systematic verification over shell, Z and energy • Need Test & Analysis Project for automated verification (all shells, 99 elements!)

10. Electrons: range UR 1.1 Al Range in various simple and composite materials Compared to NIST database Also Be, Fe, Au, Pb, Ur, air, water, bone, muscle, soft tissue Testbed for Test&Analysis prototype

11. Electrons: dE/dx UR 1.1 Ionisation energy loss in various materials Compared to Sandia database More systematic verification planned (for publication) Also Fe, Ur

12. Electrons, transmitted UR 1.1 20 keV electrons, 0.32 and 1.04 mm Al

13. Stopping power Z dependence for various energies Ziegler and ICRU models Ziegler and ICRU, Fe Ziegler and ICRU, Si Straggling Nuclear stopping power Bragg peak(with hadronic interactions) Protons UR 2.1 UR 2.5

14. Antiprotons UR 2.3 • Dashed • Geant4 LowE proton • Solid • Geant4 LowE Quantal Harmonic Oscillator model • Dotted-dashed • Non-linear calculation by Arista and Lifschitz • Points • Experimental data from ASACUSA

15. Ions UR 2.2 Ar and C ions Deuterons

16. x x f hn  A hn0 10 MeV 100 keV q 1 MeV a small  z O small  small  C large  large  large  y Polarisation Cross section: Low Energy Polarised Compton Sample Methods: • Integrating over  • Sample  •  - Energy Relation  Energy • Sample of  fromP() = a (b – c cos2) distribution 250 eV -100 GeV UR 4.1, D.1 Scattered Photon Polarization More details: talk on Geant4 Low Energy Electromagnetic Physics  Polar angle  Azimuthal angle  Polarization vector Other polarised processes under development

17. Fe lines GaAs lines Scattered photons Fluorescence UR 3.1 Experimental validation: test beam data, in collaboration with ESA Science Payload Division Microscopic validation: against reference data Spectrum from a Mars-simulant rock sample

18. Auger effect UR 3.1 New process, validation in progress Auger electron emission from various materials Sn, 3 keV photon beam, electron lines w.r.t. published experimental results

19. Contribution from users • Many valuable contributions to the validation of LowE physics from users all over the world • excellent relationship with our user community • User comparisons with data usually involve the effect of several physics processes of the LowE package • A small sample in the next slides • no time to show all!

20. GEANT4 Medical Applications at LIP P. Rodrigues, A. Trindade, L.Peralta, J. Varela LIP – Lisbon

21. 15x15 cm2 Differences Differences 10x10 cm2 10x10 cm2 15x15 cm2 Homogeneous Phantom P. Rodrigues, A. Trindade, L.Peralta, J. Varela, LIP • Simulation of photon beams produced by a Siemens Mevatron KD2 clinical linear accelerator • Phase-space distributions interface with GEANT4 • Validation againstexperimental data: depth dose and profile curves LIP – Lisbon

22. Styrophoam Lead Electron Transport at Low Energies • Evaluation of electron range for different GEANT4 releases GEANT4 (Low+Std)

23. Dose Calculations with 12C • Bragg peak localization calculated with GEANT4 (stopping powers from ICRU49 and Ziegler85) and GEANT3 in a water phantom • Comparison with GSI data

24. Geant4 low energy validation Jean-Francois Carrier, Louis Archambault, Rene Roy and Luc Beaulieu Service de radio-oncologie, Hotel-Dieu de Quebec, Quebec, Canada Departement de physique, Universite Laval, Quebec, Canada The following results will be published soon. They are part of a general Geant4 low energy validation project.

25. Using Geant4, we calculated depth-dose curves for many different electron or photon sources: • Beams • monoenergetic beam • realistic clinical accelerator beam • Point sources • monoenergetic source • source with real nuclide energy spectra • and different irradiated media: • Homogeneous • water, Be, Mo or U • Heterogeneous • water/Al/lung/water • water/air/steel/air/water

26. Uranium irradiated by electron beam Fig 1. Depth-dose curve for a semi-infinite uranium slab irradiated by a 0.5 MeV broad parallel electron beam 1Chibani O and Li X A, Med. Phys. 29 (5), May 2002

27. Multi-slab medium irradiated by photons Fig 2. Depth-dose curve for a multi-slab medium irradiated by a 18 MV realistic clinical accelerator photon beam 2Rogers D W O and Mohan R,http://www.irs.inms.nrc.ca/inms/irs/papers/iccr00/iccr00.html

28. Water phantom irradiated by clinac beam Fig 3. Relative dose distribution for a water phantom irradiated by a 6 MeV Clinac 2100C electron beam 3Ding G X and Rogers D W O http://gold.sao.nrc.ca/inms/papers/PIRS439/pirs439.html

29. Ions Independent validation at Univ. of Linz (H. Paul et al.) Geant4-LowE reproduces the right side of the distribution precisely, but about 10-20% discrepancy is observed at lower energies

30. Dose distribution: TG 43 protocol, experimental data (S. Paolo Hospital, Savona), G4-LowE S. Guatelli’s thesis

31. Cosmic rays, jovian electrons Solar X-rays, e, p Courtesy SOHO EIT Courtesy of S. Magni, Borexino Application and more! Not only “space and medical”!

32. Team work! Geant4 Low Energy Electromagnetic Working Group + users all over the world Students • Jean-Francois Carrier • Stephane Chauvie • Elena Guardincerri • Susanna Guatelli • Alfonso Mantero • Pedro Rodrigues • Andreia Trindade • Matteo Tropeano The validation plots in this presentation have been contributed by 19 people from 9 countries Thanks to all!

33. Further physics improvements and extensions • Various projects in progress • all motivated by requirements in the URD • Some examples in the following slides • no time to show all!

34. Bremsstrahlung Models UR A.5 • Current bremstrahlung polar angle generation scheme is independent of both atomic number, Z, and emitted photon momentum, k • Does not account variations due to the screening of the nucleus by the atomic electrons • At generator level, for 50 keV incident electrons with k/T=0.7 in Ag New model (2BN) to be implemented by LIP group

35. Polarisation theory UR 1.4, 4.1 simulation Polarisation of a non-polarised photon beam, simulation and theory Ratio between intensity with perpendicular and parallel polarisation vector w.r.t. scattering plane, linearly polarised photons

36. Ongoing significant effort in OOAD

37. Other activities in the WG • Advanced examples • Simulation + analysis in a distributed computing environment • Test & Analysis • Technology transfer • Training

38. Technology transfer Particle physics software aids space and medicine M.G. Pia and J. Knobloch Geant4 is a showcase example of technology transfer from particle physics to other fields such as space and medical science […]. CERN Courier, June 2002

39. Talksin WG web • The Geant4 Toolkit: simulation capabilities and application resultsM.G. Pia et al., 8th Topical Seminar on Innovative Particle and Radiation Detectors, Siena, 2002 • Geant4: a powerful tool for medical physicsE. Lamanna et al., 8th Topical Seminar on Innovative Particle and Radiation Detectors, Siena, 2002 • Dose calculation for radiotherapic treatment on a distributed computing environmentS. Chauvie et al., 8th Topical Seminar on Innovative Particle and Radiation Detectors, Siena, 2002 • Parallel Geant4 simulation in medical and space science applicationsJ. Moscicki et al., 8th Topical Seminar on Innovative Particle and Radiation Detectors, Siena, 2002 • Simulation and analysis for astroparticle experimentsA. Howard et al., 8th Topical Seminar on Innovative Particle and Radiation Detectors, Siena, 2002 • Leipzig applicators Montecarlo simulations: results and comparison with experimental and manufacturer's dataM. Tropeano et al., 21st ESTRO Meeting, Prague, 2002 • Tools for simulation and analysisA. Pfeiffer and M.G. Pia (for the Geant4 and Anaphe Collaborations), ICHEP02, Amsterdam, 2002 • The Geant4 Simulation Toolkit and Its Low Energy Electromagnetic Physics PackageS. Chauvie et al., 44th Annual Meeting of the American Ass. of Physicists in Medicine, Montreal, 2002 • The Geant4 Toolkit: Overview  M. G. Pia, Invited lecture at the MCNEG Workshop, Stoke-on-Trent, UK, 2002 • Medical applications of the Geant4 Simulation ToolkitM. G. Pia, Invited lecture at the MCNEG Workshop, Stoke-on-Trent, UK, 2002 • Simulation software: applications and results in the bio-medical domainM. G. Pia et al., VII International Conference on Advanced Technologies and Particle Physics, Como, 2001 • From HEP computing to bio-medical research and vice-versa: technology transfer and application results   M. G. Pia et al., Plenary talk at CHEP 2001, Beijing, China, 2001 • Architecture of Collaborating FrameworksA.Pfeiffer et al., CHEP2001, Beijing, China, 2001 • Simulation For Astroparticle Experiments And Planetary ExplorationsA.Brunengo (for the Geant4 Low Energy Electromagnetic Group), CHEP2001, Beijing, China, 2001 • Geant4 Low Energy Electromagnetic Physics  M. G. Pia (for the Geant4 Low Energy Electromagnetic Group), CHEP2001, Beijing, China, 2001 • The GEANT4 simulation toolkitG. Santin, Monte Carlo Workshop for Nuclear Medicine applications, July 2001 • Geant4: simulation capabilities and application results  M.G. Pia (for the Geant4 Collaboration), EPS-HEP Conference, Budapest, July 2001

40. Resources New collaborators: • Pablo Cirrone (INFN-LNS) • Luis Peralta, Pedro Rodrigues, Andreia Trindade (LIP, Lisbon) (new institute, applied) • Group from INFN-Gran Sasso also interested to join Status on 1 September 2002

41. Conclusions • We do a lot of work • and we do our best to do it well… • a rigorous software process, continuous SPI • very effective team-work, several brilliant and motivated young collaborators • We have plenty of interesting physics results in a new (and difficult) simulation domain • significant progress in the last year in a few problematic areas • don’t forget in what status we inherited the package, when the WG was created! • A huge user community worldwide • excellent, constructive relationship between users and developers • more support for our activities outside the Collaboration than inside??? • Many new projects in the WG, not only physics • Testing system, analysis, advanced examples, distributed computing, technology transfer More information in http://www.ge.infn.it/geant4/lowE/index.html