1. 11 October 2006Basic Layout of LER G. de Rijk1 Basic Layout of LER  The basic idea  VLHC type magnets  LER in the LHC tunnel  Layout  LER experiment bypass and injection scheme  SPS-LER-LHC injection sequence

2. 11 October 2006Basic Layout of LER G. de Rijk2 The basic idea  LER is a two beam machine  Two-in-one superferric combined function magnets  Inject beam from SPS into LER  Accumulate and shape the two beams in LER  Accelerate from 0.45 TeV up to 1.5 TeV  Transfer the two beam simultaneously in a single turn transfer into the LHC So:  Beam coasting time in LHC at injection energy (0.45 TeV) is reduced to the minimum (~10 ms)  Starting at 1.5 TeV the LHC can ramp faster  Beam is coasting at 0.45 TeV in LER in a “clean” maching

3. 11 October 2006Basic Layout of LER G. de Rijk3 Pre-accelerator LER  Pre-accelerator of 0.45 TeV => 1 TeV- 1.5 TeV in the LHC tunnel.  Ring of small transverse dimensions  Cheap magnets  Using VLHC ‘pipetron’ magnets.

4. 11 October 2006Basic Layout of LER G. de Rijk4 Pipetron - VLHC magnets FNAL  0.45 TeV injection at 0.48 T  1.5 TeV top at 1.595 T (72kA)  Gradient ~ 3%  Enlarged magnet aperture v 28 mm x h 40 mm VLHC LER H. Piekarz et al.

5. 11 October 2006Basic Layout of LER G. de Rijk5 Pipetron - VLHC magnets FNAL  1 m prototype tested at FNAL  Reported at MT19 H. Piekarz et al.

6. 11 October 2006Basic Layout of LER G. de Rijk6 Feasibility study - tunnel space Fits above the LHC ring at a 1.35 m beam-to-beam vertical distance (some cabling exceptions in straight sections)

7. 11 October 2006Basic Layout of LER G. de Rijk7 Feasibility study - tunnel space

8. 11 October 2006Basic Layout of LER G. de Rijk8 Feasibility study - tunnel space

9. 11 October 2006Basic Layout of LER G. de Rijk9 Layout (1)  Arc cells match the LHC cell length  4 Combined function magnets (12 m) per half cell Bmax 1.595 T, G = ± 4.969 T/m  Dispersion suppressor with combined function magnets (8 m).  Short straight sections with corrector magnets are similar to those for VLHC  Straight sections have 4 m long quads  Low beta insertion is common with the LHC talk by J. Johnstone FNAL

10. 11 October 2006Basic Layout of LER G. de Rijk10 The challenge: Experiment bypasses There are: 2 large (ATLAS & CMS) 2 less big (ALICE & LHCb) experiments to bypass For this study we assume that after an upgrade only ATLAS and CMS will remain

11. 11 October 2006Basic Layout of LER G. de Rijk11 Experiment bypass options 1. Bypass the experiments in a tunnel typically be at least 2 x 300 long Digging a bypass requires to empty the main tunnel at the junctions An extra shaft is probably needed for each bypass At least a year shutdown Very costly: >20 MCHF per tunnel Remark: the optics could be very problematic 2. Bypass the experiments through the detectors Drilling a hole through the detectors is probably a very bad idea There is a hybrid option with (1) passing in between the muon chambers : to be studied later Remark: the optics could be very problematic 3. Bypass the experiments through the LHC beampipe Bump beam down (and back up) into beam experimental beam pipe Study concentrates on this option

12. 11 October 2006Basic Layout of LER G. de Rijk12 Injection / bypass scheme Use existing injection channel Fast switched transfer lines in IP1 and IP5 RF, dump and cleaning separate from LHC

13. 11 October 2006Basic Layout of LER G. de Rijk13 Injection / bypass scheme (2)  Beam train of 89  s + gap of 3  s  To inject in LHC switch Fast Switching Dipole off during 3  s gap  The following FSD go off in sequence when the gap passes LER ops: D and FSD on LHC ops: D and FSD off

14. 11 October 2006Basic Layout of LER G. de Rijk14 Transfer between LER and LHC (1)  Horizontal separation 150 ==> 0 mm  Vertical separation 1350 ==> 0 mm - One set of fast switched dipoles only at the LHC side of a transfer line - horizonal bend 2 is made by tilting the vertical bends Talks: J. Johnstone and H. Piekarz

15. 11 October 2006Basic Layout of LER G. de Rijk15 Transfer between LER and LHC (2) Talks: J. Johnstone and H. Piekarz

16. 11 October 2006Basic Layout of LER G. de Rijk16 Timing sequence  Injection plateau of ~ 400 s  Ramp up time from 0.45 TeV to 1.5 TeV is 300 s.  Fast Pulsed Dipoles ramp down in 3  s

17. 11 October 2006Basic Layout of LER G. de Rijk17 Timing sequence  Neighbouring fast switching magnets switch off at different times  Timing sequencing and magnetic decoupling of FSDs are important

18. 11 October 2006Basic Layout of LER G. de Rijk18 Machine set-up option After an LHC dump: If the low beta insertions can be ramped down fast Then LER can setup while the LHC main magnets are still ramping down

19. 11 October 2006Basic Layout of LER G. de Rijk19 Conclusing remarks  LER fits into the LHC arcs (with ease).  The main two-in-one superferric combined function magnets are of an existing technology  The bypass through the experimental beam pipe is possible.  Dipole magnets which can be switched off fast, are crucial.  LER is a dedicated injector for the LHC.  A future application is LER as DLHC injector