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LEIR

LEIR. Presented by M. CHANEL. CONTENTS. PHASE 1*: LEAD on LEAD general view LEIR Injection and cooling Lattice and machine elements PHASE 2* : A on A Upgrade programme* : a on B Linac3 in the south Hall or not?? Planning Summary. * Names from LHC PR 450:D. BRANDT.

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LEIR

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  1. LEIR Presented by M. CHANEL PSDAYS: EVIAN 2001

  2. CONTENTS • PHASE 1*: LEAD on LEAD • general view • LEIR Injection and cooling • Lattice and machine elements • PHASE 2* : A on A • Upgrade programme* : a on B • Linac3 in the south Hall or not?? • Planning • Summary * Names from LHC PR 450:D. BRANDT

  3. Stacking tests of lead ions requested Source+efficiency Losses+charge state

  4. Hear D. Kuchler’s talk LINAC3 • Improved afterglow pulsed ECR source(450ms pulse length but increased current from 100mA to 300mA Lead 27+; Leir uses 150ms max). • Add a cavity to ramp momentum by 1% • Pulsing from ~1 Hz to 10Hz. • Possible use of a LIS** (>5 mA Lead27+, 5ms) * Collaboration Catania, Grenoble, Cern, GSI | ** Collaboration with ITEP,TRINITI.

  5. LEIR • Combined H/V/P multiturn injection: inclined septum+ momentum variation of incoming beam such the injection orbit(D dp/p+bump) remains the same during injection. 50% injection efficiency reachable. • Cool and stack the freshly injected beam by electron cooling in 400ms max. • up to 4 injection-cooling-stacking cycles • Acceleration and ejection (h=4) at T=64(or more) MeV/u: energy choice is a compromise between the limit of incoherent tune shift in PS, the time between bunches for ejection kicker and stacking time in SPS/LHC.

  6. LEIR Injection • Combined injection gives lower et (better cooling time) compared to normal multiturn but increases mom. spread (good long. cool.). • Combined injection implies large D and D/~5 (D=10, b=3).

  7. X-Y plane after 40 turns • X and y projected distributions

  8. Cooling and Stacking • where q is the relative difference in angle between the ions and electrons [qi=(/)] • the parameter hecool = Lcooler/Lmachine • and Ie is the electron current. • A and Q: atom mass and charge state • Electron cooling theory gives: • Large b desirable but ion beam size should remain smaller then e-beam size + mind to e-beam space charge….optimum around b=5m

  9. Lattice • Good for injection and cooling…still 2 periods • tune=(1.8,2.7) • longitudinal acceptance reduced to dp/p=1% • 5 quad families, more flexible.

  10. LEIR cycle for LEAD ions

  11. A word on vacuum • During the tests in 1997, the Lear vacuum was good (~5E-12T without beam) but the lost lead ions (e-ion recombination..lead 54+ or res. gas charge exchange or..) degas the chamber walls. One lead ion releases ~105 molecules!!!! • At end of linac3, tests of different vacuum chamber treatment are under way. • Hope outgassing can be reduced by appropriate treatment of the vacuum chamber(Argon glow discharge?) • Already known: when ions are lost perpendicularly to walls, outgassing is decreased.

  12. Linac3 in South Hall or Not?? • The proposition to move the Linac3 was proposed: • to avoid the loop limited to Q/A<0.25 • to avoid pulsing the E2 line between injection-ejection and change some massive magnets. • What has changed?: • we have found scenarii where Q/A needed>0.25 is possible whatever is the ion, • It could be advantageous for some light ions with a source intense enough to pass by the PSB(3 turns injection) and then reduce the filling time of the LHC, • the cost of moving the linac3(all resources taken into account) is probably higher that the change of massive magnets. • Anyway there is the need of two external lines.

  13. Planning

  14. Summary • Accumulation schemes for different kind of ions are well advanced • Electron cooling of heavy ions is defined. • Space charge limits both in LEAR and PS together with cooling/filling time are the main limitations especially for light ions. Limits in SPS to be estimated. • Vacuum degradation due to losses is a challenge . • IBS and conservation of high beam density is another challenge. • Blow-up due to stripping improved in TT2(2002?). • Planning established. • All technical systems are being specified. Complete design report end of the year 2001.

  15. PSB-PS? • PSB: for light ions(He,O,Ar?) with a source of 1mAe, cp/Q~310 MeV/c/ch 15%, 3-4turns injection it could be possible even using the 4 rings( change filling scheme in LHC…???)

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