1. V.Dzhordzhadze1 The Tunnel Background Source Study Vasily Dzhordzhadze University of Tennessee Trigger Upgrade Meeting BNL, April 12, 2004

2. V.Dzhordzhadze2 The Run3 background study

3. V.Dzhordzhadze3 South arm, gap 4 + o W E MuID GUI and MuID hit area

4. V.Dzhordzhadze4 Green - neutrons The Run 4 “Typical” MARS simulated interaction Neutrons can scatter from the tunnel walls and go around the shielding blocks

5. V.Dzhordzhadze5 The MARS Run4 simulation Result 3034 3337 3748 W 0.42 0.46 0.52 E 4535 3475 7223 0.63 0.48 1.00 2764 3632 0.38 0.50 -------------------- 2041 3010 0.28 0.42 1178 1057 1026 0.16 0.15 0.14 197 125 123 0.03 0.02 0.02 Simulation contradicts with experimental observation On left-right particle fluxes W E

6. V.Dzhordzhadze6 Run 4 Shielding and Geometry Geometry with magnet cryogenic vessels Extended geometry with QM04 Beam-scrape at QM01 Beam-scrape at D0 (1) Beam-scrape at D0 (2) MARS simulation models

7. V.Dzhordzhadze7 The Run4 with cryogenic vessels

8. V.Dzhordzhadze8 The Run4, beam-scrape at QM04

9. V.Dzhordzhadze9 The Run4, possible beam-scrape points QM01 D0 FCAL

10. V.Dzhordzhadze10 The Run4, beam-scrape at QM01

11. V.Dzhordzhadze11 The Run4, beam-scrape at D0 (1)

12. V.Dzhordzhadze12 The Run4, beam-scrape at D0 (2)

13. V.Dzhordzhadze13 The MARS Run4 simulation Results Vessels QM04 W E W E 0.38 0.47 0.56 0.09 0.10 0.07 0.65 0.62 1.00 0.17 0.29 0.21 0.42 0.79 0.11 0.22 ----------------------- ---------------------- 0.39 0.43 0.20 0.21 0.26 0.18 0.18 0.11 1.00 0.10 0.03 0.03 0.03 0.01 0.03 0.02

14. V.Dzhordzhadze14 The MARS Run4 simulation Results Beam-scrape at QM01 W E 0.28 1.00 0.51 0.30 0.49 0.36 0.23 0.25 -------------------------- 0.13 0.24 0.07 0.23 0.09 0.01 0.01 0.01

15. V.Dzhordzhadze15 The MARS Run4 simulation Results (1-MuID close) scrape at D0 (2-MuID away) W E W E 0.26 0.20 0.12 0.24 0.21 0.12 0.76 0.54 0.30 0.70 0.74 0.35 1.00 0.36 1.00 0.47 ----------------------- ---------------------- 0.94 0.31 0.98 0.42 0.37 0.31 0.08 0.39 0.61 0.12 0.04 0.02 0.01 0.05 0.03 0.01

16. V.Dzhordzhadze16 MARS simulation correctly describes experimental picture under the assumption of the beam scrape at D0, not at QM01, QM03 or QM04 Observed in simulation picture is also in agreement with the relative count rates of S5 and S6 counters To check the validity of this observation it will be good to put two additional scintillators close to the beam pipe after the D0 If the beam-scrape at the D0 is correctly predicted by simulation, the shielding strategy arises naturally: Put a shielding material around the beam pipe just after the D0 or put shielding symmetric to FCAL Conclusions

17. V.Dzhordzhadze17

18. V.Dzhordzhadze18 MuID Shielding Configuration for Run 4

19. V.Dzhordzhadze19 South Tunnel East Side West Side New Cranes FCAL MuID Wall Shielding Beam