Photonuclear reactions in Geant4: inefficiency of electromagnetic calorimeters.

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1 Photonuclear reactions in Geant4: inefficiency of electromagnetic calorimeters. Mikhail Kosov, ITEP/, Krare 2005 May 26, CHIPS model of photonuclear reactions in Geant4 (CHIPS/GHAD). 2. Test9 frame for physics validation of photonuclear reactions. 3. Geant4 example for studying of inefficiency of EM calorimeters. May 26, 2005 Mikhail Kosov, ITEP/, Krare 2005

2 Milestones of the CHiral Invariant Phase Space model. Critical temperature and hadronic masses (EPJA-4,265); p p annihilation at rest (Quasmon, quark fusion, EPJA-8,27); Inclusive CHIPS for nuclear fragmentation (Phys.Rev.C,50,R54); Evaporation algorithm (phase space of nucleons, EPJA-9,4); Pion capture at rest (quark exchange, EPJA-9, 4); Photonuclear reactions below 50 MeV (EPJA-9, 42); Photonuclear absorption cross sections and (e, e ) (EPJA-4,377); Fragmentation of Nuclear Giant Resonance (under development); String+CHIPS=QGSC for high energy nuclear reactions (MC2000); Structure Functions & (ν, µ) (submitted to Frontier Science 2005); May 26, 2005 Mikhail Kosov, ITEP/, Krare 2005

3 4 p p e + e - CHIPS MC 00 T (MeV) Pion multiplicity s (GeV) May 26, 2005 Mikhail Kosov, ITEP/, Krare 2005

4 Non-relativistic evaporation package in CHIPS Ultra-relativistic phase space of 3D partons: n n Φ n (E) = δ( E i E) δ 3 ( p i ) i= dn pde i= n i= ( 2k s ) n 2. d 3 p i 2E i s n 2, Non-relativistic phase space of protons and neutrons (no fragments): Φ n (W n ) = Φ n (W n ) δ(w n W n T ) T dt dw n W 3 2 n 5 2 n dn T de ( TWn ) 3 2 n 4. W A = U A + E excitation, U =.7 MeV (an internal parameter). May 26, 2005 Mikhail Kosov, ITEP/, Krare 2005

5 Nuclear clusterization parameters Quark exchange forces clustering nuclei. P ν = Ca ν ω ν ( + ω) a + ε ν, ω is a clusterization parameter, ε ν - clusterization on nuclear surface, ε ν>2 = 0. a = n ε i i= Parameters found for pion capture in Eur. Phys. J. 9 (2000) 4: 9 Be 2 C 28 Si 59 Co 8 Ta ε ε ω May 26, 2005 Mikhail Kosov, ITEP/, Krare 2005

6 Inclusive CHIPS, invariant phase space, K-variable. Baryons (one dimensional consideration of quark exchange): k + M = E + q, k = p q k = E M + p 2 Mesons (one dimensional consideration of quark fusion): k + q = E, k q = p k = E + p 2 Antibaryons (antiquark-antidiquark fusion): k + q = M + E, k q = p k = E + M + p 2 Edσ d 3 p dσ { } pde EXP (k )[ v cos(θ)] T v 2 May 26, 2005 Mikhail Kosov, ITEP/, Krare 2005

7 p+ta=h+x, 400 GeV, 90 o (E/A)*d 3 σ/d 3 p, mb/gev (E/A)*d 3 σ/d 3 p, mb/gev E kin, GeV k=(e+p-b*m)/2, GeV May 26, 2005 Mikhail Kosov, ITEP/, Krare 2005

8 Leptonuclear cross section d 2 σ dydq 2 = α πq 2 (S T L (σ T + σ L ) S L σ L ), S T L = y y + y Q2 4E 2 m2 l Q 2 (y 2 + Q2 E 2 ) y 2 + Q2 E 2, S L = y 2 ( 2m2 l Q 2 ), m l mass of the lepton ( ) d 2 σ ea dydq 2 = αy ( y 2 )2 πq 2 + y 2 + Q2 4 m2 l Q 2 σ γ A(K, Q 2 ), K = ν ( x). E 2 σ γ A = ( x)σ γ (K)G 2 D(Q 2 )e b(k) r+c(k) r3, r = 2 ln(q2 + ν 2 K 2 ). May 26, 2005 Mikhail Kosov, ITEP/, Krare 2005

9 σ abs (mb) H Cu Partovi64 LeviSandri89 JENDL Armstrong72 PDG collection MacCormick96 Muccifora99 Wyckoff65 Gavrilov57 KAERI CNDC Bianchi96 Michalowski77 Brookes73 Arakelian78 Caldwell79 C Pb LANL Wyckoff65 KAERI Muccifora99 Bezic69 Burgov63 Ahrens75 Heynen7 JENDL Ghedira85 Bianchi96 Michalowski77 Arakelian78 Caldwell79 Caldwell79 Arakelian78 Muccifora99 Veyssiere70 Lepretre8 LANL Ghedira85 Bianchi96 Brookes E γ (MeV) May 26, 2005 Mikhail Kosov, ITEP/, Krare 2005

10 Test9 is a tool of the 9/29 club in Geant4. geant4/tests/test29 & geant4/test/test9 contain CHIPStest executable; separate files: test9 c.cc for CHIPS processes and test9 g.cc for GHAD processes (test9 f.cc for FLUKA C++ wrappers?); the first tests are the existing tests of photo-nuclear reactions; projectile PDG Code = 0 in chipstest.in means all projectiles ; target PDG Code = 0 in chipstest.in means all targets ; PAW kumac files start CHIPStest=test9 with a chipstest.in input file and convert the output ASCII files to ntuples for plotting; if GHAD has two or more processes for the same projectile, one can edit the test9 g.cc file and select the necessary process; one can collect new data and create a new test9 subdirectory. May 26, 2005 Mikhail Kosov, ITEP/, Krare 2005

11 Universal G4QCollision CHIPS process for all hadrons. CHIPS has one G4QCollision process for all hadrons and photons; CHIPS conserves energy, momentum, charge, and baryon number; test9 checks conservation of E, p, Q, and B for each event; test9 defines a special (Z, N) monoisotopical G4Element; target nuclei are defined by the 9SPPPNNN code (C2= ); projectiles are defined by PDG codes, energy/momentum are in MeV; virtual projectiles (e.g. γ, π, or K ) can have nonzero kinetic energy (if the kinetic energy is 0, it is calculated from the momentum); nuclear clusterization and s-suppression regulate multiplicities. May 26, 2005 Mikhail Kosov, ITEP/, Krare 2005

12 Sequence of the input data in the chipstest.in file. T critic s2q etas nop mom en ppdg targpdg nev frn frdb clpr VaM sola T critic - CHIPS critical temperature, important only for high energies; s2q - s-quark suppression, important for strange particles production; etas - suppression of η mesons, important for secondary photons; nop - secondary clusters 22:A<5(minimum), 52:A<9, 82:A<3...; mom - momentum in MeV/c, it can be zero for the Capture At Rest; en - total energy (MeV), if en=0, it is calculated from mass and mom; ppdg - particle code of the projectile (e.g. γ=22, π =-2, p=222); targpdg - nuclear code for the target isotope (new=0szzzaaai); May 26, 2005 Mikhail Kosov, ITEP/, Krare 2005

13 Sequence of the input data in the chipstest.in file (continue). T critic s2q etas nop mom en ppdg targpdg nev frn frdb clpr VaM sola nev - the number of events to be simulated (it can be changed by kumac s according to the input parameter regulating statistics); frn - a percentage of quasi-free nucleons on the nuclear surface; frdb - a percentage of quasi-dinucleons on the nuclear surface; clpr - clusterization parameter for the dense part (.-frn-frdb); VaM - Vacuum/NuclearMatter ratio for the Quark Fusion (vacuum) and Quark Exchange (nuclear matter) hadronization mechanisms; sola - the cos(θ) definition of the absorption solid angle for secondary mesons after antibaryon annihilation at rest on nuclear surface; May 26, 2005 Mikhail Kosov, ITEP/, Krare 2005

14 γa in the GDR region ( photon subdirectory). this is a low energy reaction where mesons can not be produced; the low energy photon is absorbed by a quark, not by a nucleon; after the quark level hadronization (Quark Exchange) is exhausted, the nonrelativistic evaporation package NEVA of CHIPS starts; G4QCollision has new (not GHAD) γa,ea,µa interfaces for CHIPS; GHAD photonuclear interfaces had problems near threshold (different masses), now 50/50 protons/neutrons are radiated on the threshold; the results of simulation can be worse because the detailed nuclear masses data base of CHIPS was changed recently (because of the energy/momentum conservation test) by the rough Geant4 data base; Branchings of other channels (p, d, α) must be compared with data. May 26, 2005 Mikhail Kosov, ITEP/, Krare 2005

15 σ(γ,nx)/σ(γ,tot) /04/ Photoneutron production part of total photonuclear cross section 9 Be σ(γ,nx)/σ(γ,tot) C σ(γ,nx)/σ(γ,tot) O E γ (MeV) σ(γ,nx)/σ(γ,tot) E γ (MeV) 40 Ca E γ (MeV) E γ (MeV) May 26, 2005 Mikhail Kosov, ITEP/, Krare 2005

16 2005/05/ /05/ /05/04.9 σ(γ,nx)/σ(γ,tot) Li σ(γ,nx)/σ(γ,tot) Be σ(γ,nx)/σ(γ,tot) C E γ (MeV) E γ (MeV) E γ (MeV) 2005/05/ /05/ /05/04.9 σ(γ,nx)/σ(γ,tot) O σ(γ,nx)/σ(γ,tot) Al σ(γ,nx)/σ(γ,tot) Ca E γ (MeV) E γ (MeV) E γ (MeV) May 26, 2005 Mikhail Kosov, ITEP/, Krare 2005

17 γa below π meson threshold ( gamma subdirectory). Published in Eur. Phys. J. A9 (2000) 4, and 42. the VaM parameter (vacuum/matter) isn t used as there is no mesons. the cross section values are not used yet (they are hardwired). an angular dependence is still there, but the hard part is overestimated; photonuclear reactions below π meson production threshold need more data and dedicated tuning of the first interaction part; no comparison with GHAD is done because it uses CHIPS for γa reactions, but some difference can be there because GHAD uses different parameters of CHIPS and uses QGS at high energies; more comparison with data are needed above the π meson threshold; An angular dependence at low energies is important for inefficiency. May 26, 2005 Mikhail Kosov, ITEP/, Krare 2005

18 2 C(γ,p) reaction at E γ = 23 MeV 2 C(γ,p) reaction at E γ = 5 MeV dσ/p p de p dω p (nb MeV -2 sr - ) dσ/p p de p dω p (nb MeV -2 sr - ) k = (p p +T p )/2 (MeV) k = (p p +T p )/2 (MeV) May 26, 2005 Mikhail Kosov, ITEP/, Krare 2005

19 40 Ca(γ,p) spectral cross section 2 C(γ *,p) spectral cross section dσ/p p de p dω p (nb MeV -2 sr - ) Θ = 60 o Θ = 90 o Θ = 50 o E γ =60 MeV dσ/p p de p dω dω p dω e (pb MeV-3 sr -2 ) Parallel kinematics ω = 20 MeV q γ = 585 MeV Θ qp < k = (p p +T p )/2 (MeV) k = (p p +T p )/2 (MeV) May 26, 2005 Mikhail Kosov, ITEP/, Krare 2005

20 2 2005/05/ C(γ,p) reaction at E γ = 23 MeV /05/ C(γ,p) reaction at E γ = 5 MeV dσ/p p de p dω p (nb MeV -2 sr - ) dσ/p p de p dω p (nb MeV -2 sr - ) k = (p p +T p )/2 (MeV) k = (p p +T p )/2 (MeV) May 26, 2005 Mikhail Kosov, ITEP/, Krare

21 A(γ,p) and A(γ,d) spectral cross section at E γ =59-65 MeV 0 2 protons 0 2 deuterons dσ/p p de p dω p (nb MeV -2 sr - ) Θ = 60 o Θ = 90 o Θ = 50 o dσ/p d de d dω d (nb MeV -2 sr - ) Θ = 90 o k = (p p +T p )/2 (MeV) k = (p d +T d )/2 (MeV) May 26, 2005 Mikhail Kosov, ITEP/, Krare

22 The raredecay calorimetry advanced example in Geant4. The raredecay calorimetry advanced example inherits N07 example; Three sections of the calorimeter can be parallel or sequential; de is used for charged particles and track length for neutrons; User class (derived from G4Run) accumulates energy and track length; Geometry of the sections can be changed without re-building; Materials of gaps and absorbers can be changed for all sections; Only one sensitive detector class is used for all sensitive detectors; Different production thresholds can be set for different regions; Can measure contribution of photonuclear reactions to the inefficiency; Can evaluate efficiency of different absorbers and active detectors. May 26, 2005 Mikhail Kosov, ITEP/, Krare

23 Conclusion CHIPS is the only package in Geant4 for photonuclear reactions. Unique approximation of photonuclear cross-sections is made. The 9/29 club is open for contribution of users (high energies). The normalization by total cross-sections in test9 is not yet done. Tests of photonuclear reactions at higher energies must be added. To improve low energy simulation of photonuclear reactions the old Geant4 data base of nuclear masses can be upgraded to the 2003 level. User demands for the raredecay calorimetry example are necessary. Simulation can help to minimize photon inefficiency of calorimeters. Simulation can help to extrapolate results of test beam measurements. May 26, 2005 Mikhail Kosov, ITEP/, Krare