LEIR Presented by M. CHANEL PSDAYS: EVIAN 2001

CONTENTS PHASE 1*: LEAD on LEAD PHASE 2* : A on A 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

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

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.

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.

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).

X-Y plane after 40 turns X and y projected distributions

Cooling and Stacking Electron cooling theory gives: 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 Large b desirable but ion beam size should remain smaller then e-beam size + mind to e-beam space charge….optimum around b=5m

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.

LEIR cycle for LEAD ions

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.

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.

Planning

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.

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…???)