Hadronic Physics Validation II Dennis Wright Geant4 Review CERN April 2007

Outline ● Full setup/thick target validations – head-to-head comparison with other MC codes ● Checking conservation laws – user requests – model limitations ● Other efforts ● Making other codes available within Geant4 2

Inter-comparison with Other Codes ● 7 validation tests proposed for Hadronic Shower Simulation Workshop at Fermilab, September 06 – covered wide energy range – head-to-head comparison of (5-6) simulation codes for each test – data sets agreed upon beforehand – voluntary participation ● Due to short time scale, not all tasks could be completed ● Agreed to make this a regular exercise 3

Task 1: 12.9 GeV/c p on Al 4

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Task2a:  + from 158 GeV/c p on C 7

Task2a:   from 158 GeV/c p on C 8 Editor: S. Striganov, Fermilab

9 Task2a:  +   from 158 GeV/c p on C (Geant4 only - QGSP)

Task3: p + Al at 67 GeV/c ->  + X red: Geant4, blue: MARS, green: PHITS 10

Task3: p + Al at 67 GeV/c ->   X red: Geant4, blue: MARS, green: PHITS 11

Task 3: p + Al at 67 GeV/c -> p  X red: Geant4, blue: MARS, green: PHITS 12 Geant4 is version 8.1 and QGSP

p + Al at 67 GeV/c -> p X (FTFP in v8.2 ref02) 13 p  

Task4: PAL with Geant4 prediction 14

Task 5: Total Energy in a Cu Absorber 15 Ed. S. Striganov, Fermilab

Task 7: Energy Deposited in W Rod 16 Ed. S. Striganov, Fermilab

Checking Conservation Laws ● User requests – common complaint: excess energy produced in LEP, HEP, QGS models – response: some excesses can be fixed, others inherent in model ● Energy/momentum conservation – tests now in place to check for non-conservation – QGS model: all known energy/momentum non-conservation has been fixed – LEP, HEP: some non-conservation fixed, some left for new model ● Charge, strangeness conservation – LEP, HEP models inherently violate charge conservation – can fix only by going to new model 17

Energy deposited by 1 GeV n-bars in steel calorimeter Blue: before fix Red: after fix 18

Other Efforts (1) ● Quasi-elastic (charge exchange) reactions – validation of n-A interactions showed that the GHEISHA- derived elastic process had many problems – some of these were corrected but the cross sections are still incorrect and there is double-counting of quasi-elastic reactions – original GHEISHA code did not neatly separate charge exchange and elastic – some problems may have been introduced in conversion to C++ ● Separate quasi-elastic process being considered – separate cross section data set required (n-n easy, n-A more difficult) – charge-exchange would have to separated from some models which now include it to avoid double-counting 19

Other Efforts (2) ● Physics list validations – done in consultation with EM group – 4-5 most used physics lists regularly checked ● Beginning development of new validation suites – similar to cascade, CHIPS model verification test suites – for cross sections, medium energy models, high energy models ● Regular generation of HSSW validations – add new tasks – repeat every 18 months ● Application validations – specific tests in medical, space and HEP fields 20

Making Other Hadronic Codes Available Within Geant4 ● INCL/ABLA – interface available – currently being incorporated into Geant4 ● completion by end of this year ● JQMD – interface for nucleus-nucleus collisions available ● Lawrence Livermore Neutron Database – currently working with LLL on alternative to HP neutron models 21

Making Other Hadronic Codes Available Within Geant4 ● DPMJET – interface being developed for nucleus-nucleus collisions – ready by Autumn 2007 ● MARS – part of older version of MARS (MARS13) (E < 5 GeV) available in Geant4 (parameterized, no CEM) – to be discontinued in Geant4 9.0 (lack of use, obsolete) – new version not available for incorporation or interface at this time 22

Making Other Hadronic Codes Available Within Geant4 ● Currently no plans to develop interface for FLUKA or MCNP(X) – these are not simply models but full simulation packages – some license issues involved as well 23

Backup slides

Open Issues (1) ● Current validation practice: – problems identified (shower shape, neutron fluence, etc.) – compare/validate the applicable physics lists using full setup results – verify that the critical models in the physics lists are working properly by comparing to thin target data ● The above practice: – has identified several problems which are now being fixed – ensures that the most-used physics lists and models are more thoroughly validated – tends to neglect other physics lists, models, energy ranges 25

Open Issues (2) ● Development of a comprehensive validation strategy – ideally, each physics model, physics list would be validated for each release – not practical given current hadronic group manpower ● Presenting validation results to users – too much to present (confusing to users?) – some validation data is pending publication and cannot be made public ● Archiving, accessing older validations – organization, centralization – large number of files 26

Open Issues (3) ● Participate in more inter-code validation comparisons – not many Geant4 people expert at using other codes, and vice versa – due to HSSW, there will be more full setup comparisons but model-to-model comparisons will be difficult ● Finding time/manpower to do validation for “stable models” – codes such as precompound, de-excitation, etc. have not undergone recent development, and have not been recently validated 27

Task6:  - in Fe-Scint Calorimeter 28