DPA Modeling in MARS15

Transcription

1 DPA Moeling in MARS15 N. Mokhov (Femilab) NBI2017+RaDIATE IVIL Tokai Japan Septembe

2 Outline Intouction DPA Theoetical Moels fo Chage Paticles an High- Enegy Neutons an Databases fo E < 150 MeV Neutons all with Defect Pouction Efficiency Benchmaking Against Poton Data an Reacto Neuton Data Impact of Damage Efficiency on DPA Peictions in Vaious Applications Summay Ceits to M. Eistee A. Konobeev V. Ponskikh I. Rakhno S. Stiganov an I. Topin 2

3 Intouction Atomic isplacement coss-section is a efeence way to chaacteize the aiation amage inuce by neutons an chage paticles in cystalline mateials. To evaluate a numbe of isplace atoms Noget Toens an Robinson popose in 1975 a stana (so-calle NRT-DPA) which has been wiely use since. Nowaays this fomulation is ecognize as suffeing fom some limitations: it is not applicable fo compoun mateials oes not account fo ecombination of atoms uing cascae cannot be iectly valiate an has no eclae uncetainties as evaluate coss sections usually have these ays. Upgaing the DPA-stana is one via inclusion of esults of Molecula Dynamics (MD) Binay Collision Appoximation (BCA) fo pimay aiation efects which suvive afte elaxations of pimay knock-on atom (PKA) cascaes. 3

4 4 Atomic isplacement coss section N numbe of stable efects pouce E isplacement theshol σ/t - ecoil fagment enegy (T ) istibution Non-ionizing enegy loss (NIEL) N numbe of atoms pe unit volume T - amage enegy=total enegy lost in non-ionizing pocess (atomic motion) t t T E t t T A Z A Z T N T A Z A Z E ) ( ) ( max = å ò s s t t T E t t ni T A Z A Z T T T A Z A Z E N x E ) ( ) ( max å ò = s 4 Atomic Displacement Coss-Section an NIEL

5 Recoil Enegy Distibutions s el /T (b/mev) Fe Elastic E n =14.5 MeV ENDF/B-VII.0 ENDF/B-VII.1 JEFF TENDL-2011 s/t (b/mev) Fe (nn') E n =14.5 MeV ENDF/B-VII.0 ENDF/B-VII.1 JEFF TENDL s/t (b/mev) Fe (n2n) E n =14.5 MeV Recoil enegy (MeV) ENDF/B-VII.0 ENDF/B-VII.1 JEFF TENDL Total istibution s/t (b/mev) Fe INC+PE+EQ DISCA-C (nonelastic pat) E n =14.5 MeV Recoil enegy (MeV) ENDF/B-VII.0 ENDF/B-VII.1 JEFF TENDL-2011

6 NRT Stana Moel to Calculate a Numbe of Fenkel Pais an Damage Enegy M.J. Nogett M.T. Robinson I.M. Toens Nucl. Eng. Des (1975) T N = 0.8 2E T T = 1+ k( Zt At Z A ) g( T Zt At Z A ) T Z A - ecoil fagment enegy=pimay knock-on (PKA) enegy chage an atomic mass Z t A t - chage an atomic mass of iaiate mateial Nuclea physics (T T ) + soli state physics (N ) NRT-DPA is successfully applie to coelate ata fom many stuies involving iect compaison fom iffeent iaiation envionments 6

7 Efficiency Function (1): Stolle MD Paametization Coections to NRT to account fo atom ecombination in elastic cascaing. Database base on MD simulations. Its paametization efficiency function ξ(t)=n D /N NRT is use fo seveal yeas in MARS15 (=1 if >1 since 2016). Tempeatue epenence. The calculations of Stolle (J. Nucl.Mate. 276 (2000) 22) fo ion at K show some tempeatue epenence of the numbe of stable efects. At the same time the compaison of isplacement coss-sections fo p+fe calculate using Stolle efect geneation efficiency with the isplacement coss-sections eive by Jung (J. Nucl. Mate. 117 (1983) 70) fom low tempeatue expeiments shows vey goo ageement. 7

8 Efficiency Function (2): Nolun ARC-DPA Nolun s the ARC-DPA concept (athemal ecombination-coecte DPA in MARS15 since 2016): The ecombination pocess oes not equie any themally activate efect migation (atom motion is cause pimaily by the high kinetic enegy intouce by the ecoil atom) this ecombination is calle athemal (i.e. it woul also happen if the ambient tempeatue of the sample woul be 0 K). The ac-pa concept allows empiical valiation against fozen efects at cyogenic tempeatue (wheeas NRT is an unobsevable quantity). N Moifie NRT = 1 T x ( T ) 2.5E 0 E T < T 2.5E < E < 2.5E < T with efficiency function x ( T ) = (2.5E / T ) 8

9 DPA Moel in MARS15 (2016) Enegy of ecoil fagments an new chage paticles in (elastic an inelastic) nuclea inteactions is use to calculate atomic isplacement coss sections using NRT moel with an w/o amage efficiency fo a numbe of stable efects; contibution fomsub-theshol paticles is teate aitionally Atomic sceening paametes ae calculate using the Hatee-Fock fom-factos an coections to the Bon appoximation NJOY99+ENDF-VII atabase fo 393 nuclies was use fo neutons fom 10-5 ev to 150 MeV to geneate MARS15 built-in atabases with an w/o efficiency functions In the same un/output atomic isplacement x-sections an esulting DPA in egions of inteest ae calculate in thee ways: pue NRT an those fo suviving efects with Nolun an Stolle efficiency functions ξ(t) 9

10 Expeimental Data Relevant to DPA Analysis Jung et al Geene et al an Iwamoto measue electical esistivity change ue to potons electons light ions fast an low-enegy neutons at low tempeatues an low oses. It is connecte to isplacement coss section σ D ( F E) = F s ( E) F ρ F is a esistivity pe unit concentation of Fenkel efects. This constant cannot be accuately calculate an is etemine fom measuements. Jung an Geene goups choose iffeent ρ F (μωm/u.c.) fo the same mateial Jung Geene Iwamoto Cu 2.5 ± ± 1 W 27 ± Konobeev Boees an Fishe (IOTA) note that Geene s choice fo W seems questionable taking into account late analysis 10

11 MARS15 vs IOTA an Expeiment: pal an pcu Cu Al 11

12 Low-Enegy Poton Example 30 MeV poton beam (Gaussian s x = s y = 2 cm) on 1-mm thick an 6-cm in aius Be an W iscs 30-kW beam: 1 ma p/s p/y 12

13 DPA/y in Be an W with 3 DPA Moels in MARS15 13

14 1 H-Pouction/DPA in Be an W with 3 DPA Moels in MARS15 14

15 4 He-Pouction/DPA in Be an W with 3 DPA Moels in MARS15 15

16 DPA x-sections ENDFB-VII-NJOY-MARS15: n + 12 C 16

17 DPA x-sections ENDFB-VII-NJOY-MARS15: n + 27 Al 17

18 DPA x-sections ENDFB-VII-NJOY-MARS15: n + 56 Fe 18

19 DPA x-sections ENDFB-VII-NJOY-MARS15: n + 63 Cu 19

20 DPA x-sections ENDFB-VII-NJOY-MARS15: n + 93 Nb 20

21 Potons vs Neutons on Coppe: MARS15 & Expeiment Neuton ata at 0.7 to 20 MeV match well MARS with Nolun an Stolle 21

22 Compaing to Reacto Data 1. A vey goo ageement fo n+cu DPA x-sections was foun between MARS-Nolun an Hoak an Gunion ata at an 20 MeV 2. Wok in pogess on benchmaking against TRIGA MARK neuton ata 1) Without C-sceen (fast/themal neuton fluence: 6/ m -2 ) n-g: m kban (G-155) 1/13 = pa n-g: m kban (G-157) 1/13 = pa Cascaes: m / m -3 = pa Total: pa MARS15 w/stolle: pa 2) With C-sceen (fast neuton fluence: m -2 ) Cascaes: m / m -3 = pa MARS15 w/stolle: pa 22

23 MARS15 with Thee DPA Moels: Al In Mu2e pouction solenoi neuton spectum 23

24 MARS15 with Thee DPA Moels: Cu In Mu2e pouction solenoi neuton spectum 24

25 LBNF Design Optimization MARS15 with the escibe DPA moel is use to estimate the lifetime as well as EDEP an aiological quantities - fo all the citical components in the LBNF neutino beamline fo bette esign 25

26 Neutino Specta at Fa Detecto in Optimize Design n µ n µ n e n e 26

27 Summay DPA theoetical moels fo chage paticles an high-enegy neutons an atabases fo E < 150 MeV neutons in MARS15 ae poven to pefom vey well. Stana NRT oveestimates a numbe of stable efects. Use of efect pouction efficiency ξ(t)=n D /N NRT to account fo ecombination of cascaing atoms is manatoy. Nolun an Stolle ξ(t) ae pactically tempeatue-inepenent which is goo fo cyo applications. Use of appopiate amage efficiencies mitigates the stingent DPA-NRT limitsinhigh-poweapplications 27