Radiation levels in CBMRadiation levels in CBM

• Radiation effects• iFluka (Fluka C++ interface to CbmRoot)• Fluka Geometry Models• Results• Conclusion

Radiation Damage EffectsRadiation Damage Effects

Total Ionizing Dose DisplacementDamage

Single Event Error

hard SEE soft SEE

clock

data input line

data in register

expected data in register

© T. Wijnands

2

MATERIAL CAUSE RADIATIONEFFECT

Semiconductors Electron-hole pair dose ionizationPhoton interaction photon

absorption Lattice displacement nucleon collision

Polymers Main and side chain rupture dose ionizationcross-linking degradation “ “gas evolution, radical productiondose rate

Ceramics Lattice displacements nucleon collision

trapped charge carriers dose ionizationcolor centers “ “

Metals Lattice displacements nucleon collision

nuclear reactions producing clusters “ “

voids and bubbles “ “

Radiation Effects – Rough Classification

© Lockheed Martin3

Semiconductors

Polymers

Ceramics

Metals and alloys

1E3 1E4 1E5 1E6 1E7 1E8 1E9 1E10 1E11 1E12 1E13 rad1E12 1E13 1E14 1E15 1E16 1E17 1E18 1E19 1E20 1E21 1E22 n/cm2

- no damage- mild to severe damage

- destruction

CBM

Radiation Damage to Materials/Electronics

Dose & Displacement Damage

4

iFluka MotivationsiFluka Motivations

• 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

iFluka DesigniFluka Design

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– Energy density -> Total Ionizing Dose (rad)– Fluence -> 1 MeV n-eq– etc ..

Radiation study settingsRadiation study settings

– Geometry models: • CBM cave ( based on technical drawings + modifs )• Magnets ( Muon + Active ) • MUCH ( compact design ) taken from CbmRoot• (1%) Au target

– Primary sources:• DPMJET-III (delta rays + beam / beam dump )• UrQmd (Au-Au mbias collisions @ 25 AGeV)

– Secondaries (transport):• Delta –rays: 50 KeV, hadrons 100 KeV• Low-energy neutrons library activated

FLUKA Geometry of the CBM Cave

Field Active Muon Field

Cave Global Diagnosis ( TID)Cave Global Diagnosis ( TID)

No Much

MUCH

Cave Global Diagnosis (fluence)Cave Global Diagnosis (fluence)

No MUCH

MUCH

Global Diagnosis Xsection X=0Global Diagnosis Xsection X=0

Fluence TID

MUCH

MUCH induced radiation MUCH induced radiation

Scoring planes Scoring planes

Much scoring planes

MDV+STS Scoring planes

Details : MVD @ z=5cm (TID)Details : MVD @ z=5cm (TID)MUCH no MUCH

Xsection X=0

Details : STS1 @ z= 30 cm (TID)Details : STS1 @ z= 30 cm (TID)MUCH no MUCH

Details : STS8 @ z= 100 cm (TID)Details : STS8 @ z= 100 cm (TID)MUCH no MUCH

Details : MVD @ z= 5 cm (Fluence)Details : MVD @ z= 5 cm (Fluence)MUCH no MUCH

Details : STS1 @ z= 30 cm (fluence)Details : STS1 @ z= 30 cm (fluence)MUCH no MUCH

Details : STS4 @ z= 50 cm (fluence)Details : STS4 @ z= 50 cm (fluence)MUCH no MUCH

Details : STS8 @ z= 100 cm (fluence)Details : STS8 @ z= 100 cm (fluence)MUCH no MUCH

Details : Much1 @ z= 130 cm (fluence)Details : Much1 @ z= 130 cm (fluence)MUCH no MUCH

Comparisons with other MCsComparisons with other MCs

MVD0 (TID) MVD0 Fluence

Radiation studies ( CBM-Wiki)Radiation studies ( CBM-Wiki)

Main Page Results tables

ConclusionConclusion

• MUCH option (study with Active Field Magnet)– Impact in Tracker region ( 30 cm < Z < 100 cm )– TID increases moderately with Z– Fluence increases x10 up to x100 with Z

• Soon effects due to Muon Magnet

• Results cross-checked with other MC´s

• Study of beam dump effect (PSD)• beam dump design

• Needed : feedback from detector groups

BACKUPSBACKUPS

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)

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 ?

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)

CBM Cave GeometryCBM Cave Geometry

ZY view XZ view

The electronics caveThe electronics cave