Fermilab Accelerator Physics Center MARS15 Code Developments Driven by the Intensity Frontier Needs Nikolai Mokhov Pertti Aarnio, Yury Eidelman, Konstantin Gudima, Alexander Konobeev, Vitaly Pronskikh, Igor Rakhno, Sergei Striganov, Igor Tropin ICRS-12 & RPSD-2012 Nara, Japan September 2-7, 2012
OUTLINE • Introduction • Inclusive, Exclusive and Hybrid Modes • Particle Production Event Generators • Mean Stopping Power • Coupling to EGS5 • Nuclide Production, Decay and Transmutation (DeTra) • Radiation Damage (DPA) • GUI and Visual Editor • ROOT Geometry ICRS-12, Nara, Sep. 2-7, 2012 Nikolai Mokhov et al., MARS15 Code Developments 2
Introduction MARS15 is a multi-purpose Monte-Carlo code developed since 1974 for detailed simulation of hadronic and electromagnetic cascades in an arbitrary 3-D geometry of shielding, accelerator, detector and spacecraft components with energy ranging from a fraction of an electronvolt to 100 TeV. Driven by needs of the intensity frontier projects with their Megawatt beams, e.g., ESS, FAIR and Project X, the code has been recently substantially improved and extended. New features are described in this talk. ICRS-12, Nara, Sep. 2-7, 2012 Nikolai Mokhov et al., MARS15 Code Developments 3
MARS15: Exclusive, Inclusive & Hybrid Most of processes in MARS15, such as electromagnetic showers, hadron-nucleus interactions, decays of unstable particles, emission of synchrotron photons, photohadron production and muon pair production, can be treated exclusively (analogously), inclusively (with corresponding statistical weights), or in a mixed mode.The choice of method is left for the user to decide, via the input settings. Other variance reduction techniques used in MARS: weight- window, splitting and Russian roulette, exponential transformation, probability scoring, step/energy cutoffs. Goal: Maximize computing efficiency e = t 0 /t , where t is CPU time needed to get a RMS error s equal to the one in the reference method with CPU time t 0 provided s < 20%. ICRS-12, Nara, Sep. 2-7, 2012 Nikolai Mokhov et al., MARS15 Code Developments 4
Example: EMS Inclusive Hybrid-10 Exclusive Hybrid-20 ICRS-12, Nara, Sep. 2-7, 2012 Nikolai Mokhov et al., MARS15 Code Developments 5
INCLUSIVE PION PRODUCTION Newest phenomenological MARS15 model for pion production in hadron- nucleus interactions at 0.7 to 12 GeV. Extension of earlier two-source model for these energies: s 3 d T ( 1 p cos ) p ( 1 p cos ) 2 9 8 E p ( 1 p cos ) exp( ) 1 7 3 dp p 1 p exp( T ( 1 p cos ) / p ) 3 4 6 5 Data used: HARP, LANL, JINR and LBL. p+Pb p - X HARP 3 GeV/c LANL 730 MeV ICRS-12, Nara, Sep. 2-7, 2012 Nikolai Mokhov et al., MARS15 Code Developments 6
p - Production on Lead Versus KEK data at 4 GeV/c Versus 1.46-8.9 GeV/c data ICRS-12, Nara, Sep. 2-7, 2012 Nikolai Mokhov et al., MARS15 Code Developments 7
MARS15 EXCLUSIVE EVENT GENERATORS Improved Cascade-Exciton Model code, CEM03.03 , combined with the Fermi break-up model, the coalescence model, and an improved version of the Generalized Evaporation-fission Model (GEM2) is used as a default for hadron-nucleus interactions below 5 GeV. Recent multi- fragmentation extension. The Los Alamos Quark-Gluon String Model code, LAQGSM03.03 (2012) , is used in MARS15 for photon, particle and heavy-ion projectiles at a few MeV/A to 1 TeV/A. This provides a power of full theoretically consistent modeling of exclusive and inclusive distributions of secondary particles, spallation, fission, and fragmentation products. S. G. Mashnik, K. K. Gudima, A. J. Sierk, M. I. Baznat, N. V. Mokhov, “CEM 03.03 and LAQGSM03.03 Event Generators for the MCNP6, MCNPX and MARS15 Transport Codes”, LANL LA-UR-08-2931 (2008). For quite some time, MARS has used the Dual-Parton Model code, DPMJET3 ,for the very first vertex in a cascade tree. This is used in our numerous studies for the LHC 7x7 TeV collider and its detectors, and at very high energies up to 100 TeV. ICRS-12, Nara, Sep. 2-7, 2012 Nikolai Mokhov et al., MARS15 Code Developments 8
2012 LAQGSM Developments at E < 10 GeV • New and better approximations for elementary total, elastic, and inelastic cross sections for NN and πN interactions • Several channels have been implemented for an explicit description: N+N → N+N+m π, π+N → N+m π (m<5), B+B → B+Y+K, π+B → Y+K, Kbar+B → Y+ π, and K+Kbar, N+Nbar pair production • Combination of the phase space and isobar models and experimental data • g A reactions extended down to GDR and below • Arbitrary light nuclear projectile (e.g., d) and nuclear target (e.g., He) ICRS-12, Nara, Sep. 2-7, 2012 Nikolai Mokhov et al., MARS15 Code Developments 9
LAQGSM2012 vs HARP Data: p+Ta p, p ± + X ICRS-12, Nara, Sep. 2-7, 2012 Nikolai Mokhov et al., MARS15 Code Developments 10
LAQGSM2012 vs HARP Data: p - +Pb p, p ± + X ICRS-12, Nara, Sep. 2-7, 2012 Nikolai Mokhov et al., MARS15 Code Developments 11
LAQGSM2012 vs KaoS and COSY/ANKE Data ICRS-12, Nara, Sep. 2-7, 2012 Nikolai Mokhov et al., MARS15 Code Developments 12 12
ALICE 2012 ALICE2011 (Marshall Blann et al.) is the nuclear model code based on hybrid model of precompound decay, Weisskopf-Ewing evaporation and Bohr-Wheeler fission models. It was improved and converted to event generator for nucleon, photon and heavy ion nuclear reactions at E~1 MeV to 20-30 MeV matching CEM and LAQGSM at E > 20-30 MeV in MARS15. To be released in Fall 2012 ICRS-12, Nara, Sep. 2-7, 2012 Nikolai Mokhov et al., MARS15 Code Developments 13
Mean Stopping Power in Compounds: CAB (2012) Stopping power of ions in compounds usually is described according to Bragg's rule. At low energies and for low-Z materials the difference between measured and predicted dE/dx can be as large as 20%. The "cores-and-bonds" (CAB) method developed by G. Both et al. was implemented in MARS15(2012) taking into account chemical bonds fitted to experiment for various compounds at 1 keV to 3 MeV. At higher energies, the Sternheimer and Peierls density correction algorithm for compounds is employed. ICRS-12, Nara, Sep. 2-7, 2012 Nikolai Mokhov et al., MARS15 Code Developments 14
EMS Inclusive/Exclusive Control and EGS5 Mode • Inclusive, exclusive and hybrid modeling of electromagnetic showers at all energies is now controlled in a user-friendly way globally or for specified materials. • The EGS5 code has been implemented in MARS15 for precise modeling of electromagnetic showers in the 1 keV to 20 MeV energy range globally or in specified materials: crucial, for example, for accurate description of transition effects in fine accelerator and detector structures, background studies and medical applications. ICRS-12, Nara, Sep. 2-7, 2012 Nikolai Mokhov et al., MARS15 Code Developments 15
EGS5 Mode in MARS15: 5 and 0.5 MeV e - in Cu ICRS-12, Nara, Sep. 2-7, 2012 Nikolai Mokhov et al., MARS15 Code Developments 16
EGS5 Mode in MARS15: 30-50 keV e - in Si ICRS-12, Nara, Sep. 2-7, 2012 Nikolai Mokhov et al., MARS15 Code Developments 17
MARS15+DeTra for Nuclide & Activity Calculations DeTra Module integrated in MARS15(2012) for 3-step nuclide decay and transmutation analysis: 1. Standard MARS15 run, nuclide production and stopping rates in materials specified with interface files NUCLIDES generated. Stopping rates are crucial for fine structures. 2. Same executable: built-in DeTra is called to solve the Bateman equations governing the decay and transmutation of nuclides using transmutation trajectory analysis. 3. Same executable: the output files of step 2 are processed to order specific activities and production rates. ICRS-12, Nara, Sep. 2-7, 2012 Nikolai Mokhov et al., MARS15 Code Developments 18
Benchmarking Calculated Activity: 500 MeV/A U + Cu "Measured residual activity induced by U ions with energy 500 MeV/u in Cu target“ E. Mustafin et al. Proc. of EPAC 2006, Edinburgh, Scotland, TUPLS141. Transverse target size for all samples was 50 mm, while the beam diameter in each experiment was not larger than 11 mm. Target thickness was chosen according to the ion energy: it was twice the range of U ions, so that the beam was completely stopped in the target. ICRS-12, Nara, Sep. 2-7, 2012 Nikolai Mokhov et al., MARS15 Code Developments 19
Decay Heat in Mu2e Target ICRS-12, Nara, Sep. 2-7, 2012 Nikolai Mokhov et al., MARS15 Code Developments 20
Recommend
More recommend
