Project NICA. Concept of collider detector (I)

1. Project NICA. Concept of collider detector (I)

2. Requirements • Fit into accelerator geometry. • Angular acceptance  4 . • Frequency of events detection 104 Hz. • Events mean multiplicity 600. • Momentum resolution of charged particles < 1%. • Detection of γ. • Detection of short-lived (charm) particles is not required.

3. 1 м 3,5м А 4,5 м 6 11 2 10 1 3 4 8 5 А 7 9 Concept of detector • Beams intercept point. • Silicon vertex detector. • 3. Toroidal magnet with drift tubes trekker. • 4. Toroidal magnet coil (8 coils). • 5. Multiplicity detector, electromagnetic and hadron calorimeters, TOF system (RPC). • 6. Accelerator quad. • 7. Multiplicity detector and TOF system (RPC). • 8. Electromagnetic and hadron calorimeters. • 9. Muons detector. • 10. Accelerator chamber. • 11. Collider beam. • The setup is symmetric respect the plane A-A. The right part of the setup is not shown. Setup overall dimensions are: along the beam 7 m, diameter – 4.5 m.

4. Setup main parameters

5. Distinctive feature of particles detection and identification. 1. Silicon vertex detector pitch is chosen to be 0.2 – 0.5 mm which is 10 times higher then technologically possible now. This choice provides 10 times chipper device. Coordinate accuracy 0.1 mm of single measurement is quite sufficient for hyperons detection and reconstruction of events with multiplicity  600. 2. Rotation of particle with momentum 2 GeV/c in magnetic spectrometer is  60 mrad. It is to be compared with angle of multiple scattering in drift tubes tracker – 0.4 mrad. Momentum resolution is estimated to be 0.6%. 3. High demand is shown to accuracy of TOF measurement. Difference of TOF of electron and pion with momentum  0.5 GeV/c (decay of and mesons) on basis of 1.5 m is 400 ps. TOF system must have resolution 50 – 80 ps. (RPC).

6. Distinctive feature of particles detection and identification. 4. Electromagnetic calorimeter with shower maximum detection may drastically improve capability of electron – hadron separation.

7. One more remark on the physical program. Emphases on high multiplicity trigger.

8. The paramount important parameters of present research are energy density and temperature of hadronic matter. These values are determined by primary energy of nuclei and its impact parameter. An another independent way to control thermodynamic state of system is to select events with predetermined multiplicity of secondary products. Technical way to achieve this goal is implement effective high multiplicity trigger sensitive both to charged and neutral secondary. The domain of very high multiplicity z > 4, z=n/<n> was not yet studied (VHM) nether in NN nor in AA collisions. The higher is multiplicity the higher is energy dissipation, higher is achievable density and deeper is thermalization process. Near the threshold of reaction all particles get small relative momentum. The kinetic energy approaches to potential one what is necessary condition for onset of phase transitions. In thermalized cold and dense hadronic gas as consequence of multiboson interference a number of collective effects may show up.

9. Comparison of longitudinal and transverse momenta behavior in c.m.s. Manifestation of “transverse flow” ? p z p 0.2 x pp 70 GeV Complete thermalization? 0 20 30 40 50 60 70 Manifestation of longitudinal flow ?

10. Multiplicity distribution in Pb+Pb interactions at Elab =160 A Gevas measured by WA98 setup at CERN 104 101

11. One can extrapolate data to 6 order of magnitude down and presumably reach multiplicity  840. One can speculate to reach a new mechanism of hadronization and a new fashion of phase transitions. Since we are plane to collect 5109 central events per year we may get 5103 very exotic and possibly unusual events.

12. Lessons we lerned performing "Thermalization" project at U-70 Cost and manpower estimate.

13. Lay-out of the SVD setup at U - 70. • Scheme of the SVD installation at U - 70. • С1, С2 -beam scintillation and Si-hodoscope; • С3, С4 - target station and vertex Si-detector; • 1, 2, 3-the drift tubes track system; • 4 - magnetic spectrometer proportional chambers; • 5- threshold Cherenkov counter; • 6 - scintillation hodoscope; • 7 - electromagnetic calorimeter.}

14. SVD hall U-70 proton beam

15. Setup schematic view. Cherenkov counter, 36 ch. Micro strip VD, 10 000 channels. Drift tubes tracker, 2400 channels Magnetic spectrometer, 10 000 ch. EMC, 1500 cells.

16. Silicon micro strip vertex detector. An exsample of foil targets imaging. 4 mm

17. Silicon micro strip vertex detector. An exsample of pC interaction event. 28 charged tracks

18. Silicon vertex detector 40 cm

19. Module of drift tubes tracker. 1 m

20. Assembly od drift tubes tracker.

21. Charm particle D0 detection pC D0 X, 70 GeV.

22. Search for pentaquark +, 2005.K_0 found in magnetic spectrometer. Total statistics: Signal=392, Backg=1990. Significance=8σ. 1.500 1.600

23. Cost and manpower of two components of SVD setup at U-70. • Silicon vertex detector. 10 000 channels. Designed and implemented 1999 – 2002, Selenograd and MSU. Cost: 250 th. $. Manpower: 4 persons. Cost per channel: 25 $. • Drift tubes tracker. 2400 channels. Designed and implemented 2003 – 2005, PPL JINR. Cost: 55 th. $. Manpower: 4 persons with 30% occupancy. Cost per channel: 22 $.

24. Cost estimate. * As estimated from SVD (U-70)

25. Some expert’s remarks. • Peter Senger. 1. Do not build TRD -- Agree. 2. Do not build Silicon vertex detector. – Interesting idea to think about. 3. Do not build calorimeters -- Agree do not build hadron calorimeters. But EM calorimeters are very important. 4. Detailed feasibility studies have not been made and will take years. -- Disagree. 5. The time for realization is strongly underestimated. -- Disagree. • N.Xu. 1. A pair of ZDC are needed. -- Not sure. Need to think. 2. Take a staged approach of detector construction. -- Agree.Good idea.

26. Conclusion

27. We are optimistic and looking forward to see NICA operation.