iFluka : a C++ interface between iFluka : a C++ interface between Fairroot and FlukaFairroot and Fluka

• Motivations • Design• The CBM case:

– Geometry implementation– Settings for radiation studies– Global diagnosis

• Conclusion and Outlook

MotivationsMotivations

• Non intrusive interface • Fluka used in analogue or biased mode• C++ programming using Fairroot Class Library

– Generators ( Urqmd, etc ... )– Field maps definition– Standardized IO using Fairroot file structure– Parameters containers

DesignDesign

FairRoot

iFluka FeaturesiFluka Features

• Fluka version 2006.3b• C++ FairRoot interface to native Fluka

– Enable usage of FairRoot class library directly• precise field maps info (CbmFieldMap)• external generators ( CbmUrqmdGenerator etc ..)• etc ...

– FairRoot IO supported• All Root IO +• Stack info: (CbmMCTrack)• Detector scoring info stored using CbmMCPoint

• General Fluka mesh normalization routine– directly linked with Fluka executable– Fluences -> Dose– Fluence -> 1 MeV n-eq– etc ..

Radiation study settingsRadiation study settings

– Geometry: • CBM cave ( based on technical drawings + modifs )• Magnet + (1% ) target + MUCH ( compact design ) taken

from CbmRoot– Primary sources:

DPMJET-III (delta rays + beam / beam dump )

UrQmd (Au-Au central collisions )– Secondaries (transport):

Delta –rays: 50 KeV, hadrons 100 KeV

Low-energy neutrons library activated– Magnetic field map from CbmRoot– 1 Mev n-equivalent fluence normalization

New Geometry of the CBM Cave

Scoring planes Scoring planes

Much scoring planes

MDV+STS Scoring planes

CBM Detectors (2)CBM Detectors (2)

CBM Cave GeometryCBM Cave Geometry

ZY view XZ view

NIEL (1)NIEL (1)

• Displacement damage on Si lattice proportional to non ionizing energy transfer (NIEL) ( n, p, π+/-,e).

• To characterize the damage efficiency of a particle at E – Use of the normalized damage function D(E)/D(1Mev)– Tables taken from A.Vasilescu and G. Lindstroem

( http://sesam.desy.de/menbers/gunnar/Si-func.htm)

• Normalization of hadron fluence Φ :

Φ (1 MeV n-eq) = ∫ (D(E)/D(1 MeV)) Φ(E) dE

with D(1 MeV) = 95 MeV mb.

• Φ (1 MeV n-eq) : equivalent 1 MeV-n fluence

producing the same bulk damage

NIEL (2)NIEL (2)

Cave charged particles fluenceCave charged particles fluence

DPM

UrQmd

Cave neutrons fluenceCave neutrons fluence

DPM

UrQmd

The electronics caveThe electronics cave

Much : Energy densityMuch : Energy density

Much: Charged particles fluenceMuch: Charged particles fluence

Much: neutrons particles fluenceMuch: neutrons particles fluence

ConclusionConclusion

• iFluka ready to be used for radiation level

studies• On going work:

– More detailed Geometry– run time conversion to ROOT format for all

Fluka estimators– Normalization routine in C++– Comparison with TFluka (Validation)

( Collaboration with ALICE )

CBM radiation environmentCBM radiation environment

• Detectors– MVD + STS– MUCH

• Estimators:– Energy density ( GeV/cm3/primary )– Fluence ( 1 Mev n equivalent : n-equiv/cm2/primary)

CBM detectors radiation levelCBM detectors radiation level

GeometryGeometry

Scoring planes Scoring planes

Much scoring planes

MDV+STS Scoring planes

MVDs energy densityMVDs energy density

STS Energy density (1) STS Energy density (1) Sts 1 Sts 2

Sts 3 Sts 4

Sts energy density Sts energy density

STS 5STS 6

STS 7STS 8

MUCH energy densityMUCH energy densityMUCH 1 MUCH2

MUCH 3 MUCH 4

MUCH energy densityMUCH energy density

MUCH 5 MUCH 6

MVDs Charged particles fluenceMVDs Charged particles fluence

MVD 1 MVD 2

STS charged particles fluenceSTS charged particles fluenceSTS 1 STS 2

STS 3 STS 4

Sts charged particles fluenceSts charged particles fluenceSTS 5 STS 6

STS 7STS 8

MUCH charged particles fluenceMUCH charged particles fluenceMUCH 1 MUCH 2

MUCH 3 MUCH 4

Much charged particles fluenceMuch charged particles fluence

MUCH 5 MUCH 6

MVDs neutrons fluenceMVDs neutrons fluence

MVD 1 MVD 2

Sts neutrons fluenceSts neutrons fluenceSTS 1 STS 2

STS 3STS 4

Sts neutrons fluenceSts neutrons fluenceSTS 5 STS 6

STS 7 STS 8

MUCH neutrons fluenceMUCH neutrons fluenceMUCH 1 MUCH 2

MUCH 3 MUCH 4

MUCH neutrons fluenceMUCH neutrons fluence

MUCH 5 MUCH 6

ConclusionConclusion

• iFluka used to estimate fluences for MVD , STS and MUCH

• Need to overlay results from UrQmd with DPM (beam dump)

• Need more input from detector groups

• Compare with real data ( TRD ... ) and other MC ?