The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia Results from simulations of the production of secondary particles at the pipe walls M.Baznat 1, K.K.Gudima 1, E.I.Litvinenko 2, Yu.Murin 2 1 Institute of Applied Physics, Academy of Science of Moldova, Moldova 2 JINR Dubna, Russia

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia Outline Motivation of this study for CBM LAQGSM generator Rapidity Transport of the spectators – nuclear fragments Testing configurations of the beam pipe at the STS region Secondary particles and the pipe walls Conclusion

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia LAQGSM high-energy event generator LAQGSM describes reactions induced by both particles and nuclei at incident energies up to about 1 TeV/nucleon, generally, as a three-stage process: IntraNuclear Cascade (INC), followed by pre-equilibrium emission of particles during the equilibration of the excited residual nuclei formed after the INC, followed by evaporation of particles from and/or fission of the compound nuclei.

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia LAQGSM related publicaitons LAQGSM03.03: a) “CEM03.03 and LAQGSM03.03 Event Generators for the MCNP6, MCNPX, and MARS15 Transport Codes” S. G. Mashnik, K. K. Gudima, R. E. Prael, A. J. Sierk, M. I. Baznat, and N. V. Mokhov, LANL Report LA- UR ; E-print: arXiv: v2 [nucl-th] 12 May 2008 b) S. G. Mashnik et al., LANL Report LA-UR ; E-print: arXiv: v1 [nucl-th] 12 Sep c) K. K. Gudima and S. G. Mashnik, Proc. 11th Internat. Conf. on Nuclear Reaction Mechanisms, Varenna, Italy, June 12–16, 2006, edited by E. Gadioli (2006) pp. 525–534; E-print: nucl-th/ LAQGSM03.01: S. G. Mashnik et al., LANL Report LA-UR , Los Alamos (2005). LAQGSM: K. K. Gudima, S. G. Mashnik, A. J. Sierk, LANL Report LA-UR , Los Alamos, Quark-Gluon String Model (QGSM): N. S. Amelin, K. K. Gudima, V. D. Toneev, Sov. J. Nucl. Phys. 51 (1990) 327–333; [Yad. Fiz. 51 (1990) 512–523]. Sov. J. Nucl. Phys. 51 (1990) 1093–1101; [Yad. Fiz. 51 (1990) 1730–1743]. Sov. J. Nucl. Phys. 52 (1990) 1722–178, [Yad. Fiz. 52 (1990) 272–282]

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia LAQGSM Au-Au sqrt(S)=5AGeV rapidity (5000 events)

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia Interface to LAQGSM data Class constructor: MpdLAQGSMGenerator (const char* fileName, const Bool_t use_collider_system=kTRUE); Class usage in simulation macro: fRun->SetName("TGeant4"); MpdLAQGSMGenerator* guGen= new MpdLAQGSMGenerator(filename); primGen->AddGenerator(guGen);

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia Geometry: Muon Magnet + 30 silicon planes: 0.3mm 0.004mm Event generator: LAQGSM Input: a) “beam”, b) Au-Au, c) Au-p; Sqrt(S)=5 AGeV Transport: Geant4 The special testing configuration A:

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia A:Transport of “the beam” with this configuration

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia A: LAQGSM Au-Au sqrt(S)=5 AGeV 5000 events transported fragments

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia A: LAQGSM p-Au sqrt(S)=5 AGeV 5000 events transported fragments

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia A: Primary protons and fragments at z=50 and z=100 cm Protons, z=50cmProtons, z=100cmFragments, z=100cm AuAu: pAu:

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia Geometry: Muon Magnet + 8 silicon planes: 0.08mm Event generator: LAQGSM Pipe: conical tube from Be or Al (with wall 2mm, and in B case 1mm Be) STS: 8 plane silicon stations 0.08mm, 10cm around the pipe, standard positions Collision: Au-Au Sqrt(S)=5 GeV/u Transport: Geant4 The special testing configurations B and C: B: Be–1mm 1.6 º, Al -2mm 2.9º inside pipe: vacuum C: Be–2mm 2.5º, Al -2mm 2.5º, inside pipe: vacuum, or helium

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia B: Vertexes (r,z) of secondary particles, which came to STS planes (2200 LAQGSM events) 100%114% [100%] Be 1mm: Al 2mm:

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia B: Vertexes (r,z) of secondary electrons, which came to STS planes (2200 LAQGSM events) 76% (100%)80% [70%] (104%) Be 1mm: Al 2mm:

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia B: Vertexes (r,z) of the secondary particles, which came to STS planes, that belong to the pipe wall 53% {100%}70% [61%] {131%} Be 1mm: Al 2mm:

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia C: Secondary particles born in the pipe wall (1000events) 2mm Be+vacuum: 2mm Al+vacuum: 2mm Be+helium: 2mm Al+helium: 100% 111% 100.5% 114% B: Be 1mm - 78% ; Al 2mm – 102%

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia Maximal hit densities (per cm 2 per event) Allb allt allp z302.7 Allb allt allp z352.3 Allb allt allp z401.8 Allb allt allp z Allb allt allp z Allb allt allp z Allb allt allp z Allb allt allp z b<10 allt allp z302.4 b<10 allt allp z352.1 b<10 allt allp z401.6 b<10 allt allp z b<10 allt allp z b<10 allt allp z b<10 allt allp z950.3 b<10 allt allp z b<10 prim allp z302.2 b<10 prim allp z351.9 b<10 prim allp z401.4 b<10 prim allp z b<10 prim allp z600.6 b<10 prim allp z700.4 b<10 prim allp z b<10 prim allp z Be+vacBe+helAl+vacAl+hel all b<10 b<10 prim Al 2mmBe 1mm C: B:

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia C: Secondary particles – hit density per cm 2 per event Be+vac Al +vac z=30cm z=50cm Max=0.23 Max=0.18 z=100cm Max=0.26 Max=0.2 Max=0.07 Max=0.21

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia C: Secondary electrons – hit density per cm 2 per event Be+vac Al +vac z=30cm z=50cm Max=0.25 Max=0.18 Max=0.14 Max=0.21

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia C: Secondary electrons for different b ranges Be+vac Al +vac z=30cm z=50cm z=100cm

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia B: Secondary electrons for different b ranges Be+vac Al +vac z=30cm z=50cm z=100cm

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia Conclusion The pipe walls made from aluminium and berillium are very similar in respect to the secondary particle production (only 10% difference, but Al is much cheaper). The pipe cone angle less than 2.5° has the following disadvantages: -- big part of the spectator particles, which should be measured to define the centrality of the event, can not be registered by PSD; -- these spectator particles create a lot of secondary particles when pass through the pipe walls and when pass through the STS parts made from silicon.

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia BACKUP SLIDES

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia

LAQGSM intranuclear cascade model

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia The latest improvements of LAQGSM code

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia B: Vertexes (r,z) of secondary particles, which came to STS planes

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia

B: All particles – hit distributions (arb.scale) Be 1mm: Al 2mm: z=30cm z=50cm

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia Magnetic field behaviour near x=0 z=100cm

The 3rd Work Meeting of the CBM-MPD STS Consortium, 1–4 June 2009, Sortavala, Karelia, Russia At large impact parameters the most of spectator nucleons are bound in fragments. The NA49 collaboration. Eur. Phys. J., A2, 383, (1998) Experimental data : the deposited energy for different types of spectators in dependence of the centrality