Hadronic Physics Validation II

Dennis WrightGeant4 Review

CERN16-20 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

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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

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Task 1: 12.9 GeV/c p on Al

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Task 1: 12.9 GeV/c p on Al

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Task 1: 12.9 GeV/c p on Al

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Task2a: + from 158 GeV/c p on C

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Task2a: from 158 GeV/c p on C

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Editor: S. Striganov, Fermilab

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Task2a: + from 158 GeV/c p on C(Geant4 only - QGSP)

Task3: p + Al at 67 GeV/c -> + Xred: Geant4, blue: MARS, green: PHITS

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Task3: p + Al at 67 GeV/c -> Xred: Geant4, blue: MARS, green: PHITS

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Task 3: p + Al at 67 GeV/c -> p Xred: Geant4, blue: MARS, green: PHITS

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Geant4is version 8.1and QGSP

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

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p

Task4: PAL with Geant4 prediction

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Task 5: Total Energy in a Cu Absorber

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Ed. S. Striganov, Fermilab

Task 7: Energy Deposited in W Rod

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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 calorimeterBlue: before fix Red: after fix

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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

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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

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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

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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

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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

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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

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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

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Task6: - in Fe-Scint Calorimeter

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