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Wire scanners for LHC LHC-BI Review Workshop 2001 - J. Koopman. Outline. Basics. SPS and LEP review. LHC requirements. Realization. Principle of operation. Wire interacting with the beam: Secondary Electron Emission. EM pick-up. Thermo-ionic emission.
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Wire scanners for LHCLHC-BI Review Workshop 2001 - J. Koopman
Outline • Basics. • SPS and LEP review. • LHC requirements. • Realization. Wire scanners for LHC - J. Koopman
Principle of operation Wire interacting with the beam: • Secondary Electron Emission. • EM pick-up. • Thermo-ionic emission. • Shower of secondary highly energetic particles. • Repetitive bunch passing. • Collider. • Linac. shower intensity x wire position = 1-D profile. Wire scanners for LHC - J. Koopman
Rotational wire scanner Wire scanners for LHC - J. Koopman
1st generation linear wire scanner Wire scanners for LHC - J. Koopman
2nd generation linear wire scanner Wire scanners for LHC - J. Koopman
Wire supporting fork Wire scanners for LHC - J. Koopman
SPS and LEP wire scanners o Wire material: Be, C, SiO2, SiC. o Wire diameter varying from 5 to 50 um. Wire scanners for LHC - J. Koopman
LHC beam, σ = 1mm Wire scanners for LHC - J. Koopman
LHC beam, σ = 320µm Wire scanners for LHC - J. Koopman
WS as a calibration device o Absolute and direct method of measuring a beam profile. o Good signal quality. o Widely used classical device. o Robust and reliable device. BUT: o Need very stable beam. o Manage the beam energy deposition on the wire. o Limited spatial resolution at high scanning speeds. o Approximately one profile per second. Wire scanners for LHC - J. Koopman
Requirements for the LHC o Accuracy 1-2% for beam sizes down to ~220 um. o Single bunch. o Tail scans at 10-3. o Close to other profile devices. o Negligible beam blow-up. o Prevent quenching SC magnets. o Radiation level ~ 100 Gy/y. BUT: o Compromise on maximum speed 2m/s*. o Limited beam intensity: • Up to 2 Tev: 1/4th*. • From 2 to 7 Tev : 1/8th*. * J. Bosser, C.Bovet, Wire scanners for LHC, LHC Project Note 108-Rev., Oct. 1997. Wire scanners for LHC - J. Koopman
Upgrade program(1/2) o Mechanics: • Actual 2nd generation linear wire scanner with 36 µm C wire. o Position detection: Potentiometer. • Radiation hardness. • Accuracy. o Secondary particle shower detection: PMT. • High current. Wire scanners for LHC - J. Koopman
o Electronics. Profile amplitude read-out. 40Mhz. Wire position read-out. Differential, low noise. Tail scans. Motor drive & power supply. 2-3 kW peak power for 2m/s. PWM technique. o Software. Renovation. New hardware addresses and routines. Fit algorithm. New functions. Tail scans. LUT for correction. Upgrade program(2/2) Wire scanners for LHC - J. Koopman
Expected performance Wire scanners for LHC - J. Koopman
Installation o 2 x H&V downstream 4 D3 L + R. o 2 x H&V downstream 5 D2/Q4 L + R : single bunch. Wire scanners for LHC - J. Koopman
Time scale oDevelopment until: Q2/2004. oProduction preparation: Q2/2004. oManufacturing: Q3-Q4/2004. o Software : Q1/2005. oInstallation: Q1/2005-Q4/2005. oPhysics: Q1/2006. Wire scanners for LHC - J. Koopman