FLUKA simulations for particle emission in Au-Au collisions at

FAIR GSI energies Alexandru JIPA, Ionel LAZANU, Marius CĂLIN, Tiberiu EŞANU,Adrian SCURTU, Adam JINARU, Cornel BADEA, Remus PĂUN

Atomic and Nuclear Physics Chair, Faculty of Physics, University of Bucharest, Romania,

FAIR = Facility for Antiproton and Ion Research

FAIR = Facility for Antiproton and Ion Research

FLUKA Simulation Code

• FLUKA is a Particle Physics Monte Carlo simulation code, written entirely in FORTRAN, used here to calculate the ambient dose and absorbed dose in the CBM cave.

• Other usage: proton and electron accelerator shielding, target design, calorimetry, activation, detector design, cosmic rays, neutrino physics, radiotherapy, Accelerator Driven Systems

• FLUKA – complex code; can be used introducing simple cards explained in the Fluka manual.

General presentation of the FLUKA code

• Physical information is tailored to specific usage by a set of FORTRAN routines. We use here the fluscw.f and comscw.f routines, called the USERWEIG card to amplify some chosen scored quantities (fluencies and deposited energy) by certain coefficients (we obtain thus ambient dose, respectively, absorbed dose).

• iFluka it’s an adapted GSI version of FLUKA, which already embodies the two routines and many more, plus the CBM geometry, being thus a good interface between C++ and FairRoot system. We used it to run the considered examples on the GSI machines and detectors.

• For describing the nucleus-nucleus interactions, FLUKA code uses the Dual Parton Model (DPM) for energies greater than 5 GeV/nucleon, the Relativistic Quantum Molecular Dynamics (RQMD) for energies between 0.1 GeV/nucleon and 5 GeV/nucleon

• For energies lower than 0.1 GeV/nucleon, in the FLUKA code the Boltzmann Master Equation (BME) theory must be introduced (after 2005 versions of the code)

Absorbed and ambient doses• Absorbed dose = The energy lost by ionizing radiation per

unit mass of irradiated material ([Dabs] = 1Gy)• Ambient dose = the dose equivalent which would be

generated in the associated oriented and expanded radiation field at a depth of 10 mm on the radius of the ICRU sphere (30 cm diameter tissue equivalent) which is oriented opposite to the direction of the incident energy

• Effective dose = f(equivalent dose, weight factor for different tissues)

• Equivalent dose =g(average absorbed dose in a given tissue, for a given radiation, weight factor for the radiation in selected tissue)

Deq.f routine in FLUKA – 3 irradiation geometries, namely: Anterior-Posterior (AP),Irradiation Rotational (IR), WORST (WT)= Working Out Radiation Shielding Thickness - Coefficients – ICRP74, M.Pellicioni - DT,R – phantom in FLUKA - 2 sets of coefficients – there are some differences (up tp 2-3 times) - uses spline fits to coefficients - 2 routines – fluscw, comscw - selection of the weight factors and conversion coefficients for E > Emax and E < Emin - particle included – protons, antiprotons, electrons, positrons, neutron, antineutrons, photons, charged muons, charged, pions, charged kaons, , lambda, charged sigmaCalculations – for Au-Au at 15A GeVConclusions – results similar with those obtained by the other members of the collaborations (Problems of the Atomic Science and Technology 5(2007)52-56 (Nuclear Physics Investigation Series)

References

• Stefan Roesler and Graham R. Stevenson - deq99.f - A FLUKA user-routine converting fluence into effective dose and ambient dose equivalent

• www.fluka.org• http://lxmi.mi.infn.it/~battist/DoseCoeff/node2.html• http://www.gsi.de/documents/DOC-2008-Mar-48_e.html

CBM Experimental set-up• High rate, large acceptance detector system• Excellent particle identification• High-resolution tracking in a compact dipol field right after the target (Silicon)• Flexible arragement of PID detectors and calorimeters• High bandwidth DAQ with high level event selection

CBM Experiment physical goals• Deconfinement phase transition at high B

– excitation function and flow of strangeness (K, , , , )

– excitation function and flow excitation function and flow of charm (of charm (J/J/ψψ, , ψψ', D', D00, D, D, , cc))

– melting of melting of J/J/ψψ and and ψψ''• QCD critical endpoint

– excitation function of event-by-event fluctuations (K/event-by-event fluctuations (K/ππ,...),...)

• The equation-of-state at high B

– collective flow of hadrons– particle production at threshold energies (open charm?)

• Onset of chiral symmetry restoration at high B

– in-medium modifications of hadrons (in-medium modifications of hadrons (,,,, e+e-(e+e-(μμ++μμ-)-), D, D))

Particle multiplicities obtained with FLUKA Simulation code

Positive pions – 1005Negative pions – 1130 (1,12)Positive kaons – 84Negative kaons – 48 (0,57)Protons - 1153Antiprotons – 286 (0,25)

Beam energy lost – 43,0% hadrons and muons; 44,8% electromagnetic radiations;1,8% nuclear recoils and heavy fragments; 1,00% low energy neutrons, 1,6% particlesNon-included in the code lists, 8,8% - other processes

Experimental results: Freeze-out curve (T, μB) Tfo = 1614 MeV at (μB=0) new state of matter = perfect liquid?

L-QCD Predictions: TC = 151 ± 7 ± 4 MeV TC = 192 ± 7 ± 4 MeV crossover transition at μB=0 1. order phase transition with critical endpoint at μB > 0