2. PIL/LEIR Presented by M. CHANEL April 4 th 2002 -PILLEIR

3. CONTENTS LEAD on LEAD Baseline scheme Why not other alternatives LINAC3 LEIR PS Different systems Cost Planning Summary

4. Performance needed for LEAD ions 7 10 7 Lead ions/bunch in LHC at 2.7 TeV/n in a normalised emittance of 1.5  m(  2 /  h  v  ( quench limit and central detector limit) Overall transfer efficiency of 30%,  *<1.2  m at the exit of SPS,  *<1  m at the entrance of SPS after final stripping,  *<0.7  m at the entrance of PS. A total of 0.9 10 9 ions extracted from LEIR

5. GENERAL SCHEME LHC.LEAD.new.PUB

8. Stacking tests of lead ions requested Source+efficiency Losses+charge state With the lattice used, it was not possible to accelerate the beam

9. Other solutions

10. Measured by GC/MC:Emit_Pb_R4.new.xls

11. LIS 6mA, 5.5  s would suffice. But about 14MF investment. As the 6mA Laser Ion Source for lead production is still an untested prototype and many parameters are yet unknown, thus it is not recommended to base the LHC ion program on this alternative (S. Maury, Reflection on the Different Lead Ion Injection Variants for LHC, PS/AE Note 2001-019).

12. LINAC3 Improved afterglow pulsed ECR source (450  s pulse length but increased current from 100  A to 120  A -lower stability- to 200  A (RF heating from14 to 18GHz) Lead 27+; LEIR uses ~200  s). If more ions needed than change the spectrometer, move the source…expensive. Accelerate to 4.2 MeV/n,  =0.0945 Add a cavity to ramp the momentum up to 1% Stripping afterwards and use of Lead 54+ (Slightly less intensity than for Lead53, but acceptable lifetime with electrons of the cooler ) Pulsing from 0.8 Hz up to 5 Hz (10 Hz possible). (10 pulsed power supplies and thermal switches on magnets) * Collaboration Catania, Grenoble’s, Cern, GSI |

13. LEIR Combined H/V/P multiturn injection: inclined septum+ momentum variation of incoming beam such the injection orbit (D  p/p+bump) remains the same during injection. 50% injection efficiency reachable(75% on paper). Recuperate magnetic septum, bumpers. Cool and stack the freshly injected beam by electron cooling in 400 ms max. 4 injection-cooling-stacking cycles should be enough (time<1.6s). Acceleration and ejection (h=2) at T=72MeV/n: energy choice is a compromise between the limit of incoherent tune shift in PS, the time between bunches for the ejection kicker, the min RF frequency in PS and the stacking time in SPS/LHC.

14. LEIR Injection Combined injection gives lower  t (better cooling time) compared to normal multiturn but increases mom. spread (good long. cool.). Combined injection implies large D and D/  h ~5m 1/2 (D=10,  h =3).

15. Cooled beam New beam from linac D=0 E-SEPTUM X-Y plane 105 turns tracked

16. X-Y plane after 100 turns 75 injected x and y and momentum projected distributions

17. LEIR INJECTION LINE

18. Cooling and Stacking Electron cooling theory gives: –where  is the relative difference in angle between the ions and electrons [  i =  (  /  )] –the parameter  ecool = L cooler /L machine –and I e is the electron current. –A and Q: atom mass and charge state Large  desirable but ion beam size should remain smaller then e-beam size and mind the effect of the e- beam space charge…. optimum around  =5m With D=0, stack and injected beam are in the centre of the e-beam, but this not the best value for cooling.

19. Good for injection and cooling…still 2 periods tune=(1.8,2.7) longitudinal acceptance reduced to  p/p ~1% 5 quad families, more flexibility. Lattice

20. Electron cooling

22. GUN Toroïd DRIFT Dipole

25. LEIR cycle for LEAD ions

26. LEIR RF 2 RF cavities using Finemet ® built in collaboration with KEK

27. OTHERS With an electron beam of 200mA, the cooling rate is sufficient to counteract the IBS growth rate and get the emittances wanted. The beam will be maintained stable mainly during cooling (coasting beam) by a 100MHz bandwidth transverse active feedback.

28. SPACE CHARGE ALONG THE CHAIN Takes into account all the new features Note the stripping between LEIR and PS gives large 

29. LEIR EJECTION TO PS

30. 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 ~10 5 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. Already known: when ions are lost perpendicularly to walls, outgassing is decreased.

33. LEIR TDR: E. Mahner Figure 2: Dynamic pressure simulation for a 15 m long part, including a bending magnet, of the LEIR vacuum system. As input parameters the measured (at Linac3) desorption yield of  tot = 2  10 4 molec./ion and a typical gas composition (CO (72%), CO 2 (18%), CH 4 (7%), H 2 (3%)) at the beginning of beam scrubbing has been chosen. Two scenarios are displayed: a) open symbols: lumped pumps (existing from LEAR) resulting in an average pressure of 3  10 -11 Torr, b) closed symbols: lumped pumps plus linear getter (St707 strips) giving an average dynamic pressure of about 5  10 -12 Torr, a number very close to the design value. The position of the about 6 m long vacuum chamber inside the bending magnet is indicated on the x-axis.

34. PS Inject (change septum-modif. kicker) and accelerate on h=16 up to ….. h=16  14  12, split 2b. to 4 bunches and finally h=24  21 h=21 is chosen to have 100ns b. separation at flatop in LHC and it is compatible at 6.01 GeV/n with 200MHz RF system in SPS. Acceleration to 6.01 GeV/n(  =7.45), cp/Q=26. GeV/c/charge. Stripping in TT2. Change of TT2 line to have a low beta at stripper. Steve’s talk

35. TT2 (from PS to SPS, has to be changed) At stripper  h,v ~20m  5m, D~-1m Blow-up reduced by a factor 4 compared to old(normal)optic….needs MD for SPS matching.  ~0.2  m after re-matching in SPS?. Need of 4 quads, 6 power supplies +building.(mostly recuperated)

36. Different Systems (not detailed) RECUPERATION AS MUCH AS POSSIBLE Inj./Ej. Line magnet spec. 8 QTW’s, 2 BHN 1.7 and 0.4 Tm+2 cores, 2-4 DVN +instrumentation. One inclined SEH, one pulsed magnetic septum, and pulsed power supplies. All others recup. But some power supplies modifications or renewal(kickers, bumpers) Electron cooling - new by Novosibirsk+ 2 DHV’s and Old quad power supplies for solenoids. Machine magnets - all recuperated (even 4 reserve quad added ) but 6 big powers supplies (BHN+5 quads families). renewal of controls. RF - 2 cavities specified- Machine instrumentation - specifs known, most of the hardware is recuperated.

37. Different Systems (suite) Mechanics …All elements position known Vacuum specified as lifetime of lead=30s. The final study is nearly to be finished. Controls ok but not detailed.

38. PLANNING x : work on machine d: design m: manufacture t: test l: linac3 design/modif. p: ps design R: Runs L: LHC runs

39. LEIR COST (and only LEIR) /specifications/cost-recapitule/cost.2008..xls

40. Staffing (LEIR only)

41. PILcostPILcost

42. Total PIL+LEIR

43. Summary Lead ion scheme nearly finished (draft DR) Electron cooling of heavy ions is defined. Space charge limits both in LEIR, PS, SPS are harmonised. Vacuum degradation due to losses is well understood. IBS and conservation of high beam density is, as for protons, the main challenge. Planning established, cost known without contingencies, but some points are evolving. All technical systems are specified.

44. OUTLOOK People are ready to start the final design of their systems. Awaiting for financial resources.

45. Why a difference with the original price (1994)

46. TUNE SHIFT