New developments in FLUKA

1. New developments in FLUKA Paola Sala INFN Milano On behalf of the FLUKA collaboration ≈ 50 members from several institutions around the world Varenna, June 14th 2012 http://www.fluka.org

2. 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 transport In this talk some news on • Hadronic interactions in the few GeVenergy 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 applications http://www.fluka.org Paola Sala, Varenna2012

3. Hadron interactions in FLUKA: an integrated ensemble Paola Sala, Varenna2012

4. 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. Paola Sala, Varenna2012

5. Neutrino interactions (ICARUS..): Fluka has its own neutrino interaction generator, including QE, Resonance, DIS DIS uses the same chain hadronization as DPM Embedded in the FLUKA nuclear environment (PEANUT) New low-mass chain treatment-> improvements in the RES-DIS transition μ+p ->μ- +p++ Paola Sala, Varenna2012

6. Pion production close to DPM thr. Pion production from proton interactions on Be at 12.3 GeV Emitted pion spectra at different angles in the range 300 - 600 Dots: data (BNL910 expt.), histograms : Fluka + - Paola Sala, Varenna2012

7. Pion production close to DPM thr. Pion production from proton interactions on Be at 17.5 GeV Emitted pion spectra at different angles in the range 00 - 200 Dots: data (BNL910 expt.), histograms : Fluka - + + Paola Sala, Varenna2012

8. -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, 21085At has a mean life of 8.1 h, 5.6 MeV  decay and  decay to 21084Po • (, 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 • Newin 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 Paola Sala, Varenna2012

9. FLUKA: the BME Modelfor nucleus – nucleus interactions below 150 MeV/n The BME ( Boltzmann Master Equation) in FLUKA It works for Aproj,Atarg 4, E  150 MeV/A 1. COMPLETE FUSION 2. PERIPHERAL COLLISION three body mechanism with incomplete 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 BME : E. Gadioli group in Milano Paola Sala, Varenna2012

10. BME in FLUKA : (,xn) examples Excitation functions for the production of radioisotopes from  interactions on Au (left) and Pb ( right) (Data: CSISRS, NNDC) Paola Sala, Varenna2012

11. 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= multipole order =level density at excitation energy. U f = strength from single particle estimate (c)+ hindrance (F) Paola Sala, Varenna2012

12. 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 torQMD and DPMJET) • Application : prompt photon for in-vivo hadron therapy monitoring Paola Sala, Varenna2012

13. Prompt photons: benchmarks I Prompt photons measured during irradiation of water and PMMA phantoms with C ions. Photon spectra measured at 900wrt 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

14. Bragg peak position Results 95 MeV/u Counts/ion vs position along the phantom (mm) 310 MeV/u Bckg subtraction from data to equalize the bckg.level before the target Exp. Energy/tof Distribution and Window Scatter plot and exp. data taken from F. Le Foulher et al IEEE TNS 57 (2009) and later revisions Blue: fluka Red: data

15. Photon yields by 160 MeV p in PMMA Absolute comparison Preliminary 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) Paola Sala, Varenna2012

16. Spin-parity in Fermi-Break-up 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 production Straightforward example : photonuclear reaction in the GDR region Effect : residual nuclei production Application: background from induced activity in underground experiments • 12C + in GDR • J = 1- • 3 and  + 8Be impossible in L=0 • Factor 3 on 11C production Paola Sala, Varenna2012

17. Examples at LHC Paola Sala, Varenna2012

18. Application at 3.5+3.5 TeV(2.6 1010 MeV eq. in lab) 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) Paola Sala, Varenna2012

19. ElectroMagnetic dissociation at LHC Electromagnetic dissociation: sEM increasingly large with (target) Z’s and energy. Already relevant for few GeV/n ions on heavy targets (sEM ~ 1 b vssnucl ~ 5 b for 1 GeV/n Fe on Pb) Total electromagnetic and nuclear cross sections (barn) for Pb-Pb interactions at the energy sNN = 2.76 TeV Paola Sala, HSS066

20. Thanks for your attention! Work partially supported by the ENVISION and PARTNERS European programs Paola Sala, Varenna2012