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									Semiempirical MonteCarlo
      for FAZIA


          Napoli, 3-5 October, 2007

                 Giovanni Casini INFN Florence
  Silvia Piantelli and Giovanni Casini
    Some Reactions of FAZIA
           interest
At Bologna (dec 2006) we decided to start with
  some systems to study physics and spurious
  effects
• NiNi at 10 and 40 AMeV
  SnSn at 40 AMeV
  NiSn at 10 AMeV
  Kr+Ca at 5AMeV
    Deep inelastic and Fusion
           Reactions
   We started with NiNi at 10AMeV
   At the SPIRAL2 and SPES energies, dominant
    mechanisms are Deep inelastic collisions (DIC) and
    Fusion reactions (FR): we cannot disregard them!
   For the moment the DIC are better developed and
    most 'results' concern these ones, till now
   We also started some FR simulations
   We think to also include some pre-equilibrium effect
    (i.e. emission before separation in PLF-TLF for DIC
    and emission before evaporation or fission for FR
                      MCARLO tree
Random Generation of l (hbar) from l0 and lmax
where lmax=lgrazing: triangular distribution


Decision if the event is a DIC or a Fusion FUS
event (on the basis of l )‫‏‬

If DIC:
•Random extraction of TKE within the range Vcb to Ecm
•Sorting of the mass A (and thus the charge Z) of the PLF
and TLF (primary);
•Sorting of the CM-angles of the PLF and TLF (primary);
•A recipe for the Excitation energy sharing;
•A recipe for the Angular momentum sharing;
                   MCarlo: DIC




 Wilczynski plot                  DIFFUSION PLOT



These primary correlations can/must be tuned for the
various reactions. The literature gives some
parametrisations
                      MCarlo: DIC




                                           DIFFUSION PLOT



The excitation energy can be shared, in a given event, following (old)
experimental results. The general trend is: equal energy sharing for large
b; tendency to equal temperature at small b. In this picture TQP=TQT
                       MCarlo: FR
If l<lcrit we can produce (complete) fusion. We have to check the amount
of DIC vs. FR basing on the literature.
The Compound nucleus gets the whole excitation energy and travels at
0deg in the LAB with the CM energy.
The CN can decay via evaporation or via fission (to be implemented)‫‏‬
The evap vs. fission rate will be regulated basing on the literature. The
same for the mass asymmetry of Fission Fragments.
                            DECAY
The PLF, TLF or the CN are excited.


The decay occurs via light particle and IMF evaporation with a
parametrisation based on GEMINI as a function of the excited nucleus
parameter set (A,Z,E*,l)


One can also select the fission channel; the parameters of this step (mass
asymmetry, out-plane, in-plane) are suitably tuned


The kinematic quantities are written for all charged particles
                        Geometry
    (largely inspired from M.Gautier geometry)

   trapezoidal detectors with active area r‫‏‬dθ=20mm and r‫‏‬sin‫‏‬θmed dφ‫‏‬
    = 20 mm
   1‫‏‬sphere‫‏‬portion‫‏‬at‫‏‬r=1200mm‫‏‬for‫‏‬θ=0.5-22.5;‫‏‬Δθ=1.1,‫‏‬active‫‏69.0‏‬
    (1286 detectors, 20 rings)
   1‫‏‬sphere‫‏‬portion‫‏‬at‫‏‬r=1000mm‫‏‬for‫‏‬θ=22.5-43;‫‏‬Δθ=1.3,‫‏‬active‫‏51.1‏‬
    (2385 detectors, 16 rings)
   1‫‏‬sphere‫‏‬portion‫‏‬at‫‏‬r=700mm‫‏‬for‫‏‬θ=43-90;‫‏‬Δθ=1.8,‫‏‬active‫‏1364(‏46.1‏‬
    detectors, 26 rings)
   1‫‏‬sphere‫‏‬portion‫‏‬at‫‏‬r=400mm‫‏‬for‫‏‬θ=90-170;‫‏‬Δθ=3.15,‫‏‬active‫‏78.2‏‬
    (1044 detectors, 26 rings)
   TOTAL= 10346 detectors, 88 rings
   The‫‏‬active‫‏‬region‫‏‬covers‫‏‏‬Ω/4π=81%
    Geometry




θsinφ          θsinφ
In the simulation....




             θsinφ
                          Efficiency
   target thickness 0.238‫‏‬μg/cm2
   0.1μm of Si of entrance dead layer
   first Si detector: 300‫‏‬μm‫‏‬thick; second Si detector: 700‫‏‬μm‫‏‬thick
   Tof resolution:‫‏‬σdetector=(-0.3*Epart+3.3)ns;‫‏‬σbeam = 800ps
   Energy straggling:‫‏‬σBohr=(0.1569*Z2*Zsi*thick(μg/cm2)/AsiMeV
   Energy resolution:‫‏‬σelectronic=0.2MeV;‫‏‬σdetector=1.15 10-3 *Elost MeV
   if‫‏‬a‫‏‬particle‫‏‬punches‫‏‬through‫‏‬the‫‏‬first‫‏‬Si,‫‏‬E=ΔE+Eres;‫‏‬the‫‏‬particle‫‏‬is‫‏‬
    identified‫‏‬in‫‏‬Z‫‏‬and‫‏‬A‫(‏‬if‫‏‬Z<15)‫‏‏‬from‫‏‬ΔE-Eres; if Z>15, A is given from
    E and ToF
   if a particle is stopped in the first Si, if it punches through the first 30
    μm‫‏‬of‫‏‬Si,‫‏‬it‫‏‬is‫‏‬identified‫‏‬in‫‏‬Z‫(‏‬from‫‏‬the‫‏‬pulse‫‏‬shape‫‏‬technique),‫‏‬A‫‏‬is‫‏‬
    given from E-ToF;‫‏‬if‫‏‬it‫‏‬does‫‏‬not‫‏‬punches‫‏‬through‫‏‬the‫‏‬first‫‏03‏‬μm‫‏‬of‫‏‬Si,‫‏‬
    A is given from E-ToF and Z=A/2
   Hp: no PHD
    true A=58 (58Ni+58Ni 10AMeV)




     TLF                                                                PLF




Neither the PLF nor the TLF punch through the first Si: A is given from E-Tof
A from E-tof (stopped
      particles)
Punching-through particles
58Ni+58Ni   10AMeV DIC




       primary 4π   FAZIA detected (exp-equivalent)
  58Ni+58Ni            10AMeV DIC




after evaporation 4π   FAZIA detected (exp-equivalent)
58Ni+58Ni   10AMeV DIC (other parametrization)




                    primary 4π   FAZIA detected (exp-equivalent)
58Ni+58Ni   10AMeV DIC (other parametrization)




        after evaporation 4π   FAZIA detected (exp-equivalent)
58Ni+58Ni       10AMeV DIC: PLF
               evaporation




warning 1: MC original source of particles (not reconstructed)
warning 2: MC original charge for particles (not reconstructed)
58Ni+58Ni   10AMeV DIC: TLF evaporation




     warning 1: MC original source of particles (not reconstructed)
     warning 2: MC original charge for particles (not reconstructed)
     58Ni+58Ni     10AMeV DIC particle multiplicities

4π




     10
      10                               10



      10                               10



      10                               10


                                       10
                               c z>6         c z>6


           geometry + efficiency
58Ni+58Ni     10AMeV Fusion (first attempt)
      θ lab           A           E lab




                                          primary

                                     after evap. +
                                     geometry +
                                     efficiency

								
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