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Future HERA High Luminosity Performance

Future HERA High Luminosity Performance. H1. Georg H. Hoffstaetter and Ferdinand Willeke (DESY, Hamburg). 778 m. 29 March 2001. HERMES. HERA. HERA-B. Protons Electrons. 6336 m long 920 GeV protons 27.5 GeV electrons / positrons. PETRA. ZEUS. HERA: Improvements 1999/2000.

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Future HERA High Luminosity Performance

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  1. Future HERA High Luminosity Performance H1 Georg H. Hoffstaetter and Ferdinand Willeke (DESY, Hamburg) 778 m 29 March 2001 HERMES HERA HERA-B Protons Electrons 6336 m long 920 GeV protons 27.5 GeV electrons/positrons PETRA ZEUS

  2. HERA: Improvements 1999/2000 Start luminosity Beam currents: and mA Efficiency % Average over month Georg.Hoffstaetter@DESY.de

  3. Development of the Luminosity HERA Luminosity 1993-2000 Linear increase of the integrated Luminosity Integrated Luminosity (1/pb) The time for a luminosity upgrade of HERA has come Days after start of run Georg.Hoffstaetter@DESY.de

  4. The Detector Region Georg.Hoffstaetter@DESY.de courtesy B.Holzer courtesy B.Holzer Georg.Hoffstaetter@DESY.de

  5. Superconducting Magnet GO Georg.Hoffstaetter@DESY.de Georg.Hoffstaetter@DESY.de

  6. Potential Problems Focusing: • Dynamic Aperture OK? • Polarization OK?, Luminosity OK? • Can HERA be handled well? • Polarization OK?, Luminosity OK? • Too strong beam-beam force on p? • Too strong beam-beam force on e? fRF increase: Georg.Hoffstaetter@DESY.de

  7. Emittance and Lumi for 72° Optic • The Luminosity was initially too small: Lumiscan Bunch has no product distribution: • coupling • Luminosity with 72° is large as expected Georg.Hoffstaetter@DESY.de

  8. Kick Dynamic Aperture for 72° Optic x´ V2(kV) The kick where half the current is lost leads to a satisfactory dynamic aperture. x Georg.Hoffstaetter@DESY.de

  9. Polarization Ie 60% Polarization for 72° Optic • Polarization was in the spin matched 72° optic quickly brought to 63% (one day). • Harmonic bumps were immediately effective • Decoupling bumps worked well Georg.Hoffstaetter@DESY.de

  10. Luminosity for fRF Increase • 6 more measurements indicate • For the center frequency , the luminosity is increased as expected Georg.Hoffstaetter@DESY.de

  11. Too Strong Beam-Beam Force on p? 16mA 73mA Corresponding e-current after upgrade Lsis independent of e-current Tp depends on e-current Tails depend on e-current Georg.Hoffstaetter@DESY.de

  12. Too Strong Beam-Beam Force on e? Ls So far no reduction of Ls by the bunch current Ippb No reduction of Ls by the second experiment No reduction of Ls by a larger b-funktionen Georg.Hoffstaetter@DESY.de

  13. Where are the Beam-Beam Limits? Upgrade and Ip=140mA: emittance starts to grow Georg.Hoffstaetter@DESY.de

  14. Luminosity ( ) Lumi Reduction by Hourglass Effect bunch length: 6cm p e 20cm 30cm Length19cm: 12cm: Georg.Hoffstaetter@DESY.de

  15. Tune Shift with Bunch Length Effect How will the tune shift parameters change and have these been analyzed by accelerator experiments ? Georg.Hoffstaetter@DESY.de

  16. Resonances with Bunch Length Effect How will the resonance strength change and have these been analyzed by accelerator experiments ? All large resonance strength are due to the proton bunch length Georg.Hoffstaetter@DESY.de

  17. Nominal and Ultimate Parameters The performance goal of HERA is not unrealistic and should not be too hard to achieve. A shortfall of beam intensity in the short term can be compensated. Georg.Hoffstaetter@DESY.de

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