Thijs Wijnands (TS/LEA), Richard Hall Wilton (TS/LEA), Markus Stockner (AB/BI)

1. BLMs - Radmon – BSCs – BCMs for steering the beams in collision during the engineering run at 450 GeV Thijs Wijnands (TS/LEA), Richard Hall Wilton (TS/LEA), Markus Stockner (AB/BI) Input from : D. Kramer, C. Pignard, D. McFarlane, A. McPherson Special Thanks : A. Prokofiev, C. Ekström, TSL laboratories Sweden W. Hajdas, R. Brun, PSI Villingen Switzerland

2. BLM ionization chambers measure energy deposited by radiation in air • On line measurements • Dose rate • Dose • Resolution • Spatial : 4000 devices around rings (also UX) • Temporal : 90 ms – 100 s • Signal : 2.5 pA – 1 mA

3. RadMon Radiation Monitors energy deposited by radiation in Si • On line measurements • Dose rate, Dose • Hadron flux (h > 20 MeV), fluence • 1 MeV eq. neutron fluence • Resolution • Spatial : 307 devices, 250 in tunnel • Temporal : 100 ms or more • Signals : • Dose, dose rate : 1 rad • Hadron flux (h > 20 MeV) : 1e5 cm-2 s-1 • 1 MeV eq. n fluence : 1e10 n cm-2

4. Location BLMs and RadMons in tunnel RadMon under Q1 L8 6 x BLMs at Q1 L8

5. BCM- Beam Condition Monitors energy deposited by radiation in C (PCVD) • On line measurements • MIPS/s • Dose (from degradation) • Resolution • Spatial : BCM1 (8 diamonds) BCM2 (12 diamonds) • Temporal : few ns – 40 ms • Signal : 10 pA or more A. McPherson, R. Hall-Wilton

6. BSC- Beam Scintillator Counters energy deposited by radiation in plastic • On line measurements • MIPS/s • Dose rate • Resolution (CMS) • Spatial : in front of HFC • Temporal : 3-5 ns ? • Signal : ? Resolution Data to be confirmed …

7. At 1.8 m : • BCM 1- 4 diamonds Spatial resolution BCMs – CMS • At 10.9m : • BSC1 - scintillators • At 25 m : • RadMon, BLMs IP • At 14.4m : • BCM 2 - 12 diamonds A. McPherson, R. Hall-Wilton … another ~20 RadMon on cavern wall UXC55

8. Single bunch luminosities Reasonable goal for first collisions would be ~ 4 x 1010 protons/bunch From H. Burkhardt 26/01/07

9. Nominal dose rate & particle flux in TAS-Q1 region IP1 and IP5, data from N. Mokhov LHC PR 633

10. ATLAS particle flux • For L = 2.5 x 1027 cm-2s-1@ TAS • dose rate : ~1 rad/s • hadron flux : ~30 hadrons/cm/s M. Schupe

11. CMS particle flux • For L = 2.5 x 1027 cm-2s-1 @ TAS • dose rate : ~3 rad/s • hadron flux : ~10hadrons/cm2/s M. Huhtinen

12. Measured response data Proton data : • BLMs 1.8x104 gives 1 pA (60 MeV) • RADMON 1.0x105 gives 1count/s (60 MeV) • BCM 2.2x107 gives 1 pA (24 GeV) • BSC 1 count per proton ? Neutron data : • BLMs 1.6x104 gives 10 pA (174 MeV) • RADMON 5x104 gives 1count/s (174 MeV) • BCM ? • BSC ? Preliminary data !

13. BLM and RadMon calibration 180 MeV neutrons A.V. Prokofiev, M.B. Chadwick, S.G. Mashnik, N. Olsson, and L.S. Waters. Journal of Nuclear Science and Technology, Supplement 2, pp.112-115 (2002) 1 m long collimator 180 MeV p Device 7Li(p,n)7Be neutron flux : 8.8 x 104 s-1cm-2

14. Neutron Beam facility at TSL deflector magnet Li target stainless steel shielding RadMon device under test

15. BLM- RadMon neutron irradiation LHC BLM chamber RADMON SPS BLM chamber D. Kramer, M. Stockner, C. Pignard, T. Wijnands

16. BLM- RadMon neutron response D. Kramer, M. Stockner, C. Pignard, T. Wijnands

17. Measuring luminosity at 450 GeV BRAN ?

18. 450 GeV Commissioning with BSCs • Start with 4x1010 – single bunch – 1 beam • background from beam gas • alignment errors • symmetry U-D and L-R • commission DAQ • repeat for beam pipe 2 • Background low : • collide 2 single bunches • Background high : • increase bunch intensity • collide 2 single bunches • optimize lumi • Increase nbr of bunches • time resolution From Zeus - DESY

19. Optimizing singe bunch luminosity at 450 Gev • Expressing the separation of the two beams in sigma.: • 1 sigma off in one plane, lumi drops by 22% • 1 sigma off in both planes, lumi drops by 39% • 2 sigma off in both planes, lumi drops by 87% • At least L = 1.1 x 1030 cm-2 s-1 is needed • 2 sigma seems feasible, 1 sigma depends on S/N ratio M. Lamont

20. Summary • Radiation levels at L = 2.5 1027 cm-2s-1 will be extremely low : • Only BSCs will provide some signal • Commissioning Bran, BLMs, Radmons, BCMs, … • Preliminary background in entire LSS1,5 • Increase first bunch intensity to, say, Np = 8 x 1010 to • Increase S/N ratio in BSCs • Enable first lumi scans • Confirm MC simulations, background • Check S/N ratio from Bran, BLMs, Radmons, BCMs, … • If background sufficiently low : collisions with 2 or more bunches • Open issues to be addressed : • Resolution and response of BSC (CMS and ATLAS) • BSC data exchange rate (5 Hz was proposed) • Optimized layout BLMs, Radmons in LSS (from Q1 downstream)

22. Space in front of TAS at IP5 – BLM, Radmon Q1 1 x Radmon 6 x BLMs + 6 x spare

23. Picture gallery

24. Example : Radiation Monitors in SPS 2006 Bending Magnet M2 line wrong

25. N W E S Example : Radiation Monitors in CDF (1) antiprotons RADMON radiation monitor

26. Example : Radiation Monitors in CDF (2) • Integrated values for High Luminosity runs Tevatron 2005

27. Example : Radiation Monitors in CDF (3) ES seperator accident FNAL 21 Nov 2005 : • One of the electrostatic separators (ES) sparked • Magnet Quench, Vacuum lost • Several weeks downtime for repair ONW INW ISW OSW Time 011 009 167 388 Nov 21 16:12:51 2005 011 009 168 392 Nov 21 16:13:06 2005 corresponding fluence : 4x106 cm-2 (h > 20 MeV)

28. Neutron response and resolution - BLM LHC BLM chambers : • linear response : 10 pA for 1.6 x 104 n/cm2/s • noise level : 0.5 pA (analog measurement) • resolution : 1 pA For h > 20 MeV D. Kramer, M. Stockner

29. Neutron response and Resolution - RadMon RadMon monitors : • linear response : 2.6 counts/s @ 2.6 x 106 n/cm2/s • spread : +/- 1 counts per 40 counts • resolution 1 count D. McFarlane, C. Pignard, K. Cwalina, T. Wijnands