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

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

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

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

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

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 …

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

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

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

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

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

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 !

BLM and RadMon calibration 180 MeV neutrons 1 m long collimator 180 MeV p Device 7Li(p,n)7Be neutron flux : 8.8 x 104 s-1cm-2 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)

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

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

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

Measuring luminosity at 450 GeV cm-2 s-1 Np, b* BLM RadMon BCM 1.7 x 1027 4 x 1010 11 m - 1.3 x 1029 1.2 x 10 11 18 m 1.1 x 1030 2 m 1-10 pA 1 count / 10 s ? BRAN ?

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 optimize lumi Increase nbr of bunches time resolution From Zeus - DESY

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

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)

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

Picture gallery

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

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

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

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)

Neutron response and resolution - BLM For h > 20 MeV 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 D. Kramer, M. Stockner

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