New developments in FLUKA
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Transcript of New developments in FLUKA
New developments in FLUKA
Paola SalaINFN Milano
On behalf of the FLUKA collaboration≈ 50 members from several institutions around the world
Varenna, June 14th 2012
http://www.fluka.org
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A glimpse of latest developments and applications
FLUKA is a general purpose tool for calculations of particle transport and interactions with matter (all hadrons, ions, EM)
FLUKA applications range from LHC or cosmic energies down to hadron-therapy (A. Mairani’s talk) and microdosimetry
Standard tool at CERN for beam-machine interactions and radioprotection
A long and constant development of nuclear interaction models that benefits to a wide range of applications
Without forgetting EM and particle transportIn this talk some news on
Hadronic interactions in the few GeV energy range and neutrinos
Interactions of particles below 150 MeV/A Improvements in the latest stages of nuclear reactions with
examples Very high energy : examples of LHC applicationsJune 14th, 2012 http://www.fluka.org
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Hadron interactions in FLUKA: an integrated ensemble
h-hDPM + quark chain
hadronization
Resonance production and
decay
Elastic, ch.exc.
h-APEANUT
Glauber-Gribov multiple collisions
G-INC
Preequilibrium (Exciton)
Evaporation/Fragmentation or Fermi Break-up
deexcitation
A-A
DPMJET3
rQMD-2.4
BME
Muon photonuc
Neutrino Em-dissociationPhotonuclear
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DualPartonModel at its lower limit Strong experimental effort is ongoing on
particle production from beams in the few to tens of GeV range
Important for neutrino beams and interactions Challenging: too high energy for resonance
formation, too low for quark gluon based models
Fluka high energy hadron-hadron interaction model – DPM-: chain production and chain hadronization
Strong mass effects for low energy chains “standard” hadronization outside its validity region
NEW: gradual transition of low energies chains to “phase space explosion” constrained in pT , including baryons, mesons, resonances.
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Neutrino interactions (ICARUS..):
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Fluka has its own neutrino interaction generator, including QE, Resonance, DISDIS uses the same chain hadronization as DPMEmbedded in the FLUKA nuclear environment (PEANUT)New low-mass chain treatment-> improvements in the RES-DIS transition
μ+p ->μ- +p++
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Pion production close to DPM thr.
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Pion production from proton interactions on Be at 12.3 GeVEmitted pion spectra at different angles in the range 300 - 600 Dots: data (BNL910 expt.), histograms : Fluka
- +
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Pion production close to DPM thr.
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Pion production from proton interactions on Be at 17.5 GeVEmitted pion spectra at different angles in the range 00 - 200 Dots: data (BNL910 expt.), histograms : Fluka
-
+
+
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-induced reactions, -emitters
Fragmentation tail in hadrontherapy beams Radiation damage to electronics Production of residual nuclei: On heavy targets, interactions of
secondary ’s can produce dangerous radioisotopes, for instance:
(, Bi ) At : chemically reactive (halogen) and + emitters. Eg, 210
85At has a mean life of 8.1 h, 5.6 MeV decay and decay to 210
84Po (, Pb ) Po ...well known “problematic” -emitters
Some of these isotopes have exemption limits 3-4 order of magnitudes smaller than most other radioisotopes commonly produced at accelerators
New in FLUKA: - induced reactions at low energy (E < 150 MeV/A) through the BME model
At higher energies: already handled through the rQMD-2.4 and DPMJET-3 models
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FLUKA: the BME Model for nucleus – nucleus interactions below 150 MeV/n
The BME ( Boltzmann Master Equation) in FLUKAIt works for Aproj,Atarg 4, E 150 MeV/A
1. COMPLETE FUSION 2. PERIPHERAL COLLISIONthree body mechanism
withincomplete fusionone nucleon break-up and possibly transfer (at high b)pickup/stripping (for asymmetric systems at low b)
The kinematics is suggested by break-up studies.
Fragment(s) : pre-equilibrium de-excitation according to the BME theory (where available)or to the PEANUT exciton model
evaporation/fission/fragmentation/gamma de-excitation, same as for hadron-nucleus interactions
June 14th, 2012BME : E. Gadioli group in Milano
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BME in FLUKA : (,xn) examplesExcitation functions for the production of radioisotopes from interactions on Au (left) and Pb ( right) (Data: CSISRS, NNDC)
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Gamma De-excitation in Fluka At the end of evaporation : cascade of
transitions At high excitation: assume continuous level
density and statistical emission:
At low excitation: through discrete levels Tabulated experimental levels (partial coverage) Rotational approximation outside tabulations
See A. Ferrari et al., Z. Phys C 71, 75 (1996)
L
ii
ff LEfUU
dEEP ),()()(
)( L= multipole order
=level density at excitation energy. U
)12()(),( LLL EAFcLEf
f = strength from single particle estimate (c)+ hindrance
(F)
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Ongoing developments for ’s:
Extended database of known levels and transitions taken from RIPL-3 (IAEA)
Discrete level treatment extended to evaporation stage Already inserted in the released FLUKA2011.2 Photon angular distribution according to multipolarity
and spin ( effort to estimate residual spin value and direction in PEANUT, BME, rQMD)
Account for discrete levels in BME (to be extended to rQMD and DPMJET)
Application : prompt photon for in-vivo hadron therapy monitoring
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Prompt photons: benchmarks I
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Prompt photons measured during
irradiation of water and PMMA
phantoms with C ions.
Photon spectra measured at 900
wrt beam
Time-of-flight to discriminate
neutron background
Threshold at 2 MeV to discriminate prompt photons from secondary
photons, bremsstrahlung
etc.
[figures and exp. data taken from F. Le Foulher et al IEEE TNS 57 (2009),E. Testa et al, NIMB 267 (2009) 993] and later revisions
Results
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Blue: flukaRed: data
Counts/ion vs position along the phantom
(mm)
Exp. Energy/tofDistribution and
Window
95 MeV/u
Bckg subtraction from data to equalize the
bckg.level before the target
310 MeV/u
Scatter plot and exp. data taken from F. Le Foulher et al IEEE TNS 57 (2009) and later revisions
Bragg peak position
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Photon yields by 160 MeV p in PMMA
Energy spectrum of “photons” after background subtraction (collimator open – collimator closed) for 160 MeV p on PMMA. FLUKA red line, data
black line (J.Smeets et al., ENVISION WP3)
Absolute comparison
Preliminary
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Spin-parity in Fermi-Break-up
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For A<16, evaporation is substituted by Fermi break-up In cases where spin and parity of the residual nucleus are known, conservation laws, constraints on available configurations and centrifugal barrier (if L=0 is forbidden), are enforced in the fragment productionStraightforward example : photonuclear reaction in the GDR regionEffect : residual nuclei production Application: background from induced activity in underground experiments
12C + in GDRJ = 1-
3 and + 8Be impossible in L=0
Factor 3 on 11C production
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Examples at LHC
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Application at 3.5+3.5 TeV (2.6 1010 MeV eq. in lab)
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BLM response along triplet right of IR5• BLM dose per collision assuming CMS luminosity measurement and 73.5 mb proton-proton cross-section (from TOTEM)• Discrepancy possibly due to geometry model (e.g. interconnections are not modeled in detail)
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Electromagnetic dissociation: sEM increasingly large with (target) Z’s and energy. Already relevant for few GeV/n ions on heavy targets (sEM ~ 1 b vs snucl ~ 5 b for 1 GeV/n Fe on Pb)
211 )()(
21Znnd
AA
ElectroMagnetic dissociation at LHC
Reaction FLUKA ALICE (arXiv:1203.2436v1 [nucl-ex].)
Single EMD + nuclear 199 194.6 ± 0.3 stat +14.1/–12.1 systnuclear 7.67 7.5 ± 0.1 stat +0.6/–0.5 systSingle EMD 191.3 187.2 ± 0.2 stat +13.8/–12.0 syst
Total electromagnetic and nuclear cross sections (barn) for Pb-Pb
interactions atthe energy sNN = 2.76 TeV
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Thanks for your attention!
Work partially supported by the ENVISION and PARTNERS European programs
June 14th, 2012