Possible Upgrades and New Design. F. Velotti and B. Goddard

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1 Possible Upgrades and New Design F. Velotti and B. Goddard

2 Outline Possible system upgrade General principles TIDVG modifications needed MKDV modifications needed External beam dump study Requirements Concepts New layout Component specifications Consequences for the SPS Conclusions and recommendations

3 Possible system upgrade Merging together some of the solutions already proposed, a possible major modification of the whole system could be: New absorber block with separate regions Vacuum window at the entrance of the Graphite block (like the one installed in the HiRadMat experimental area) Independent MKDV systems Operate at MKDV nominal voltage (52 kv)

4 TIDVG modifications needed Aperture has to be separated from the Graphite block (22mm) Vacuum window (70 mm) TPSG to protect the gap between the aperture and the beginning of the window (h=22mm, l=2m) 2m it may be not enough

5 MKDV modifications needed Two separate PFNs and two solid state switches (already on going, [V. Senaj]) in order to have a tracking function for the whole energy range This will lead to 52 kv (maybe more) as nominal strength May need a small modification of the kicker waveform (Q20) Have to check the effect on the energy deposition -> FLUKA

6 General principles Use the TIDH and the TIDVG to dump low and high energy beams respectively Reach the TIDVG 65 mm below the nominal orbit reference TPSG to protect the system against asynchronous dump or setting error Still forbidden zone to switch between TIDH and TIDVG, but it can be very small (1 or 2 GeV maybe) 5σ CNGS beam at 400 GeV MKDVs TPSG Absorber block

7 Issues The major problem is with the Q20 optics Closed orbit bump has less effect respect to the Q26 It could be solved whether reducing the current ±15% amplitude oscillations of MKDV s waveform to ±12.5% optimizing the quads dog leg 5σ LHC (Q20) beam at 450 GeV

8 Outline Possible system upgrade General principles TIDVG modifications needed MKDV modifications needed External beam dump study Requirements Concepts New layout Component specifications Consequences for the SPS Conclusions and recommendations

9 External beam dump study It has to cover the whole energy dynamic range of the SPS (about twice of LHC) It has to be installed in a different LSS (e.g. LSS5), considering it will become radioactive Two different possible layouts have been simulated both in LSS5

10 Concept (1) The idea is to use the same extraction system as in LSS4 and adapt it in order to fulfill the specifications (bumpers, kickers and septa) 2 tracking functions one for the MKE and one for the bumpers Use 6 MSE modules to get the 12 mrad necessary to extract trough the QDA coil window In the extraction channel install the sweep magnets and then the absorber block

11 Concept (1) (cont d) The biggest problem in this concept is the MSE vertical gap: 20 mm in order to have 12 mrad at the exit of the MSE 300 GeV is the limit for a CNGS beam type 150 GeV is the limit for a LHC beam type Horizontal aperture limits: 158 GeV for CNGS 50 GeV for LHC 158 GeV 5σ - CNGS 50 GeV - 5σ - LHC

12 New septum 50 mm An idea to solve the vertical gap problem can be to produce a septum like in figure The problem is that the field is very degraded far from the coil Although it is possible to extract also switching it off at low energy MSE_2 off

13 Concept (2) Very similar to the previous one 3 septa: 3 modules with 4.2 mm coil 3+3 modules with mm coil In this case the septa have bigger vertical gap The peak current is preserved The deflection angle needed is about 10 mrad

14 There is a big gain in terms of horizontal apertures thanks to the MST-like septum (4.2 mm) Horizontally limited by the QFA.518 aperture 100 GeV for CNGS beam type Vertical limit: 58 GeV (CNGS) Concept (2) (cont d)

15 New septum + quad misaligned In order to gain in terms of horizontal aperture, the QFA can be displaced of 20mm This cause a closed bump of about 40mm amplitude in x and 20mm in y At 400 GeV, not enough deflection to reach the coil

16 Lattice function with quad x (m), y (m) misalignments Dx (m), Dy (m) lattice_mis Dx Dy x y s (m) Variables New Values Old Values X_QDA e-3 m -4.8 e-3 m Y_QDA e-3 m -5.0 e-3 m X_QFA e-3 m e-3 m Y_QFA e-3 m e-3 m

17 Components specifications Kicker system like MKE installed in LSS4 Extra impedance for SPS 4 horizontal bumpers of the same kind installed in LSS4 and LSS6 3 enlarged quadrupoles Sweep magnets (MKDH/V) Absorber block

18 Component specifications (cont ) Septum magnets for concept 1 MSE (17.25 mm thickness) (6 modules) H_y=48.5 mm (MBB aperture) I=51.71 ka the limit is 24 ka Septum magnets for concept 2 MST (4.2 mm thickness) H_y=34.5 mm (MBA aperture) (enough above 41 GeV) I=7.5 ka MSE (17.25 mm thickness) (3+3 modules) H_y=34.5 mm (enough above GeV) I=24 ka

19 Consequences for the SPS Possible to extract above 300 GeV or 100 GeV depending on the concept (for the CNGS beam type) Hence below those thresholds the internal dump is needed Radioactivity: it depends on the tunnel isolation, the absorber shield as well as losses at extraction Installation space for the extraction elements in LSS5 Civil engineering works: New tunnel from LSS5 Shielding of absorber block Cost (rough guess): 8.5 MCHF for: 3 quads + 4 bumpers + 3 septa + beam instrumentation MCHF for new TIDVG design 2-3 MCHF for fast extraction kickers (MKE-like) MCHF to move the MKDV/H

20 Outline Possible system upgrade General principles TIDVG modifications needed MKDV modifications needed External beam dump study Requirements Concepts New layout Component specifications Consequences for the SPS Conclusions and recommendations

21 Conclusions and recommendations The external beam dump concepts have big operational limitations Above 100 GeV only! Also implies major modifications in the SPS We already have external dumps for high energies (TT40/ TT60..) The modification of the current system could be a feasible solution, due to the already planed and started MKDV s upgrade BUT, still needs optimization for the Q20 optics Other issues to solve (TPSG, load on TIDVG, vacuum window installation.)

22 Concept (1) (cont ) backup MKE tracking functions

23 Concept (1) (cont ) backup Bumpers tracking functions

24 1982 study for LEP by-pass (not LHeC but SPeS!)

25 ECX5 New dump cavern SPS tunnel CE feasibility..was done for TT40 junction during SPS big bang Additional costs certainly will be some 10 s of MCHF (civil engineering, new dipoles and quads, ) Might be possible to use ECX5 as dump cavern, with shielding etc.

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