Implementation of INCL cascade and ABLA evaporation codes in Geant4

Transcription

1 Jurnal f Physics: Cnference Series Implementatin f INCL cascade and ABLA evapratin cdes in Geant4 T cite this article: A Heikkinen et al 2008 J. Phys.: Cnf. Ser View the article nline fr updates and enhancements. Recent citatins - HEIR: A High-Energy Intra-Nuclear Cascade Liège-based residual nuclear data library fr simulatin with FISPACT-II M. Fleming et al - High-Energy Activatin Simulatin Cupling TENDL and SPACS with FISPACT-II Michael Fleming et al - GEANT4 simulatins f the n_tof spallatin surce and their benchmarking S. L Me et al This cntent was dwnladed frm IP address n 16//2018 at 05:11

2 Internatinal Cnference n Cmputing in High Energy and Nuclear Physics (CHEP 07) IOP Publishing Jurnal f Physics: Cnference Series 119 (2008) di:.88/ /119/3/ Implementatin f INCL cascade and ABLA evapratin cdes in Geant4 A Heikkinen 1, P Kaitaniemi 1, A Budard 2 1 Helsinki Institute f Physics, P.O.Bx 64, FIN University f Helsinki, Finland 2 CEN-Saclay, CEA-DAPNIA/SPhN, Gif sur Yvette, France aats.heikkinen@cern.ch Abstract. We intrduce a new implementatin f the Liège cascade INCL4.2 and f the evapratin/fissin cde ABLA v3 in Geant4. INCL treats the cascade f hadrn, deuterium, tritium, and helium prjectiles f energies up t 3 GeV, while ABLA, based n evapratin and fissin, prvides a treatment f the excited nucleus prduced at the end f the cascade. Details f the implementatin f INCL and ABLA in the Geant4 9.1 release are presented and C++ perfrmance is cmpared with the riginal FORTRAN implementatin. A test suite fr validating the cde translatin is based n ROOT sftware, and we reprt n advanced features f ur testing envirnment, including scripting and autmatic dcumentatin. In additin, we intrduce a Geant4 applicatin using INCL and ABLA mdels, demnstrating the physics perfrmance and enabling cmparisns against anther Geant4 intermediate energy hadrnic mdel, the Bertini cascade. Finally we utline the future develpment f the Liège cascade, INCL5, in the cntext f the Geant4 hadrnic physics framewrk. 1. Intrductin Geant4 is a general detectr simulatin tlkit [1] prviding an extensive set f hadrnic physics mdels t meet user requirements in areas such as precisin studies f LHC hadrnic calrimetry shwer shapes, shielding studies in space applicatins, and spallatin studies in nuclear physics. A single hadrnic mdel is nt able t supprt all Geant4 user requirements in these areas which cver evapratin, intranuclear cascade and intermediate energies f up t -15 GeV. In these regins Geant4 prvides alternative mdels. The need t develp a additinal micrscpic intranuclear cdes is a Geant4 user requirement. Mre accurate mdels are particularly imprtant in detailed hadrnic calrimeter studies, since standard parametrized mdels based n Geant3 GEISHA cde [2] have truble reprducing shwer shapes accurately enugh [3] Thus we have set a gal t cmplement thery-driven Geant4 mdels in this regime (the Binary and Bertini cascades are currently mst widely used) with the inclusin f the INCL cde, als knwn as the Liège cascade. Since INCL is ften used with the independent evapratin/fissin cde ABLA, we decided t incrprate ABLA as well int Geant4. These cdes are actively develped and validated against recent data. Typical users are frm the nuclear physics cmmunity studying spallatin prcesses, fr example. With the inclusin f INCL/ABLA, Geant4 can respnd t the grwing list f user requirements frm nuclear physics cmmunity. We have cast these FORTRAN-based cdes int C++, and will prceed nw t a redesign f the mdel structure. The main bjective f the redesign prject is t c 2008 IOP Publishing Ltd 1

3 Internatinal Cnference n Cmputing in High Energy and Nuclear Physics (CHEP 07) IOP Publishing Jurnal f Physics: Cnference Series 119 (2008) di:.88/ /119/3/ facilitate easier develpment f future physics features with a clearly structured cdebase. This can be dne by fcusing n the design f prper data structures that represent the physics incrprated int INCL and ABLA in the mst natural way pssible. The next step in redesign will be t prepare well-defined data structures with access methds supprting fully the interfaces defined in the Geant4 hadrnic physics framewrk [4] This will imprve the cde quality and make develpment and debugging wrk easier. We believe that C++ releases f stand-alne INCL and ABLA cdes will benefit the nuclear and particle physics simulatin cmmunities in general, since currently Geant4 is ne f the few majr C++ -based detectr simulatin tls available. Future releases f C++ -based INCL and ABLA cdes hpefully shw a general trend in ur cmmunity t supprt and adpt cntemprary prgramming paradigms fr physics mdelling. The utline f this paper is as fllws: in sectin 2 we summarize the features f INCL and ABLA cdes. Fr detailed discussins n INCL and ABLA mdels we refer t publicatins listed in table 1. In sectin 3 the design f the first implementatin f INC4.2 and ABLA v3 is presented. Sectin 4 describes validatin between the FORTRAN and C++ versins. Finally, sectin 5 discusses the future plans f ur prject. 2. Mdeling intra-nuclear cascade and evapratin with INCL and ABLA cdes INCL is an intra-nuclear cascade cde, which is largely free f parameters. It has been carefully validated against recent spallatin data tgether with the ABLA evapratin/fissin mdel. Frm the Geant4 perspective, INCL prvides particularly interesting mdels because f its cntinuing develpment and up-t-date validatin prgram. The key features f INCL4.2 and ABLA v3 are summarized in table 1, tgether with key references t detailed descriptins f specific mdel features. Table 1. Summary f key features available in INCL and ABLA cdes. Fr detailed discussins f mdels we refer t publicatins listed in this table. INCL4.2 Key references [5, 6, 7, 8] Prjectiles p, n, pins (π +, π 0, π ) d, t, 3 He, α Energy range 200 MeV - 3 GeV Target nuclei Carbn - Uranium Mdels Wds-Saxn nuclear ptential Culmb barrier Nn-unifrm time-step Pin and delta prductin crss sectins Delta decay Pauli blcking Utility functins making INCL an independent cde ABLA v3 Key references [9, ] Supprted input Excited nuclei Mdels Evapratin f p, n, and α Fissin Output particles p, n, α, fissin prducts, and residual nuclei 2

4 Internatinal Cnference n Cmputing in High Energy and Nuclear Physics (CHEP 07) IOP Publishing Jurnal f Physics: Cnference Series 119 (2008) di:.88/ /119/3/ Implementing INCL and ABLA fr Geant4 release We have translated INCL4.2 and ABLA v3 cdes frm FORTRAN t C++ and interfaced these mdels t the Geant4 9.1 hadrnic physics framewrk using standard interfaces. Figure 1 prvides a UML diagram describing key classes prepared fr the first release. The first release included in Geant4 9.1 cntain a simple and straightfrward translatin fllwing clsely the riginal cde structure, data flw, and algrithms. Users f these cascade r evapratin cdes can build their Geant4 physics list by using the interface classes G4InclCascadeInterface, G4InclLightInInterface, r G4AblaEvapratin. Dcumentatin and example cde is prvided t clarify the details. Figure 1. Main cmpnents f the first C++ implementatin f INCL4.2 and ABLA v3 in Geant This first iteratin f the class design, visualized with Unified Mdeling Language UML, fllws clsely the rganizatin f the riginal FORTRAN cde, thus simplifying the casting t C++. T dcument the new implementatins f INCL and ABLA we have used the Dxygen dcumentatin system tgether with the advanced intrspectin features prvided by the ROOT prgramming envirnment [11]. This system generates HTML pages and graphics that can be upladed t the web and viewed by any standards-cmpliant web brwser. Figure 2 shws an example f a Dxygen call graph fr the G4InclLightInInterface::ApplyYurself() -methd and figure 3 demnstrates LaTeX supprt available in Dxygen. 4. Validating INCL and ABLA mdels in Geant4 The first implementatins f the INCL and ABLA cdes in the Geant4 framewrk were direct translatins, in which each FORTRAN functin was mapped simply t a crrespnding C++ methd. We have been able t validate in detail the quality f the translatin. 3

5 Internatinal Cnference n Cmputing in High Energy and Nuclear Physics (CHEP 07) IOP Publishing Jurnal f Physics: Cnference Series 119 (2008) di:.88/ /119/3/ Figure 2. Dxygen based HTML dcumentatin fr the INCL interface. A call graph fr the G4InclLightInInterface::ApplyYurself functin is shwn. Fr users, the n-line class brwser generated by Dxygen prvides a quick way t understand the structure f the cde. Figure 3. Wds-Saxn nuclear ptential in Geant4 9.1 INCL release. This n-line dcumentatin is prduced by Dxygen HTML-generatin. The test suite fr the validatin f the translatin is based n ROOT sftware [11]. ROOT prvides a C++ scripting system that has prven t be a gd envirnment fr sftware develpment. In additin t ROOT scripting fr hybrid FORTRAN C++ cmparisns, we used autmatic dcumentatin features t systematize unit testing. Histgrams resulting frm ROOT scripts were included recursively back t related HTML-dcuments. This functinality is made available and enfrced with the reflectivity extensin, enabling intrspectin f data structures. Figure 4 shws a cmparisn between C++ and FORTRAN versins. Clse t the target 4

6 Internatinal Cnference n Cmputing in High Energy and Nuclear Physics (CHEP 07) IOP Publishing Jurnal f Physics: Cnference Series 119 (2008) di:.88/ /119/3/ mass, the crss sectins agree reasnably well if we cnsider that the randm number generatrs are nt the same. The further the mass is frm the target ne the larger is the deviatin between the cde versins. This indicates a pssible incmpatibility between the FORTRAN and the C++ versin f the de-excitatin (ABLA part). This cnclusin is cnfirmed if we lk at the neutrn spectra prduced frm prtns f 1.2 GeV n Lead in Figure 8. Abve 20 MeV the neutrns are purely prduced by the cascade stage and we can nte a perfect agreement in energy and angle between the tw versins. Belw 20 MeV the spectrum is dminated by evapratin, we cnclude that there are sme remaining prblems in the C++ translatin f ABLA. Figure 5 extends the verificatin by cmparing INCL/ABLA perfrmance against anther mdel, the Bertini cascade, available in Geant4. n(425 MeV) + 63Cu p(1gev) + Pb (3 mm) Geant4 simulatin Number f particles 3 2 C++ FORTRAN Cunts INCL4/ABLA Bertini Mass number f the residual nuclei Figure 4. Validating FORTRAN t C++ translatin f INCL and ABLA mdels. Residual nuclei mass number distributin is shwn fr cllisins initiated by 425 MeV neutrns clliding with a 63 Cu target. Sme amunt f fluctuatin in the histgrams is expected, since the randm number generatrs are different in bth versins Mass number f the residual nuclei Figure 5. INCL/ABLA mdel perfrmance in Geant4 cmpared with the Bertini mdel which cntains an internal treatment fr evapratin and fissin [12]. This kind f cmparisn prvides a starting pint fr preparing an ptimal physics list fr a specific physics use case. Figures 6 and 7 demnstrate an example applicatin prepared fr utilizing new mdels. Visualizatin f inelastic scattering prduced by INCL and ABLA mdels is supprted with the ability t cllect simulated data int histgrams. 5. Cnclusin and future plans We have published INCL4.2 and ABLA v3 in the December 2006 release f Geant After this first release we will prceed t re-design the cdes. This step will be particularly sensitive since INCL4.2 and the upcming INCL5 C++ versins need t be released als as independent cdes. Recently there has been great interest cming frm the medical physics cmmunity t simulate treatment facilities utilizing Carbn beams. Thus, we cntinue t develp and validate these mdels and supprt ur users in particle, nuclear, and medical physics cmmunities alike. 6. Acknwledgements We are grateful t INCL develpers Jseph Cugnn (University f Liége, Belgium) and Y. Yariv (SphN-DAPNIA, CEA-Saclay and Sreq, Israël) fr supprting this prject, and cntributing t tw INCL/ABLA-Geant4 mini-wrkshps rganized in The ABLA grup kindly 5

7 Internatinal Cnference n Cmputing in High Energy and Nuclear Physics (CHEP 07) IOP Publishing Jurnal f Physics: Cnference Series 119 (2008) di:.88/ /119/3/ Figure 6. An example Geant4 9.1 applicatin utilizing INCL4.2 cascade mdel. Prtn prjectiles with 500 MeV energy are incident upn a 2 mm Pb target. A visualizatin f 0 events is shwn. Figure 7. Lg frm example applicatin assciated with Figure 6. prvided cde fr the Geant4 translatin prject. Special thanks t Christelle Schmidt (IPNL) fr prviding a C++ translatin f the fissin part f ABLA. Thanks t Alexander Hward and Albert Ribn frm CERN fr acting as Geant4 testers fr the interfaces we prvided using C++ wrapped FORTRAN-based INCL and ABLA. and validating physics against TARC data. Finally, we acknwledge Dennis Wright frm SLAC fr kindly reading the manuscript and prviding his feedback. References [1] Agstinelli A et al Nucl. Instr. & Meth A [2] Fesefeldt H C 1985 Technical Reprt PITHA [3] Rimldi A (T be published in the prceedings f CHEP 07) [4] Wellisch J P 2001 Cmp. Phys. Cmmun [5] Cugnn J et al Nuc. Phys. A [6] Cugnn J et al Nuc. Phys. A [7] Cugnn J et al Nuc. Phys. A [8] Budard A et al Phys. Rev. C [9] Junghans A R al Nuc. Phys. A [] Benlliure J et al Nuc. Phys. A [11] Brun R and Rademakers F 1997 Nucl. Instr. & Meth A [12] Heikkinen A et al nucl-th/ , SLAC-R-636 6

8 Internatinal Cnference n Cmputing in High Energy and Nuclear Physics (CHEP 07) IOP Publishing Jurnal f Physics: Cnference Series 119 (2008) di:.88/ /119/3/ p(1.2 GeV) + 208Pb (INCL4+ABLA) Crss sectin (mb) Neutrn Energy (MeV) 3 Figure 8. Example f first implementatin f INCL4.2 tgether with ABLA v3 in Geant Neutrn duble differential crss sectin fr 1.2 GeV prtn-induced reactins n Pb is cmpared with the experimental data frm Reference [8] The red histgram is prduced by the C++ versin and the black histgram by the FORTRAN versin. There is sme discrepancy between the tw versins fr energies belw 20 MeV. This indicates that the Geant4 versin f the ABLA still need t be imprved. 7