Primary beam production: progress - Extraction from LSS2 - Switching from TT20 at 100 GeV

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Primary beam production: progress

- Extraction from LSS2- Switching from TT20 at 100 GeV

B.Goddard

F.Velotti, A.Parfenova, R.Steerenberg, K.Cornelis, W.Bartmann, V.Kain, E.Carlier, A.Alekou, M.Meddahi,

L.Jensen V.Mertens, Magdalena KowalskaA.Kosmicki, J.Osborne, I.Efthymiopoulos

Extraction from LSS2

• Another test made on 3rd October with 100 GeV fast extraction, using MKP in LSS1. – Emittances of around 3.0 um (parasitic MD)– No losses in arc, even with ±10 mm bumps added at QFs

• Next test planned 22nd October using LSS6 MKE kickers with 440 GeV beam– Cycle deployed, new working point tested, simulations

made and settings defined

LSS6 -> LSS2 at 440 GeVAntiphase bump through LSS1

New SPS working point with H tune of 26.87 for 2012 test(will eventually reuse Q_split to adjust this)

LSS6 -> LSS2 at 440 GeVSimulation with aperture and envelopes

2.3 km

LSS6->LSS2 at 440 GeVExtraction point

More clearancethan 100 GeV beam

Switching from TT20:MBS magnets with open C-core

3.0 m magnetic length1.65 T max field70 mm H good field region

MBS magnet cross-section

For TT20 switch

• Only one spare 3.0 m MBS magnet exists– New series of ~10 probably required for AWAKE

• For TT20 switch, need 3 new MBS magnets• 1.65 T field is possible (field quality not really any

issue here)• Geometry already looks reasonable with ‘standard’

intermagnet drifts (for bellows and pumping ports)

TT20 optics and geometry changes

• Can manage by removing 1 MBE (211524) from the upper bending chain

MBE.211524 removed

Switch layout

3x new MBS-type magnets

Switch detail

0 5 10 15 20 25

3x new MBS

Will probably need to reorganise layout of MDLV and BSGV to gain ~30 cm longitudinally – no major issue

Impact of removing MBE dipole• Remove one vertical MBE dipole (8.4 mrad)• To arrive at same position in splitter for NA beams, need to trim

strengths of remaining 12 dipoles in this bend (total k *13/12):– Option 1: arrange as 2+10

• One family at 74.1%, one family at 115.1% (2.096 T). New cabling and one by-pass convertor needed

– Option 2: arrange as 6+6• One family at 98.4%, one family at 118.3% (2.154 T). New cabling and 2 bypass

convertors needed

• Only Option 1 looks possible (MBE field maximum 2.1 T)– Unless reduce slightly beam energy for NA to keep same peak B as for

SPS MBA/B (2.0475 T)• 2+10 then limits energy to 390 GeV• 6+6 then limits energy to 380 GeV

TT20 Trajectory changeUp to ~80 mm vertical realignment needed

over 120 m (larger for 2+10 split)

Optics changes with new dipole layoutOnly visible in DY, and this negligible (advantage of keeping bend in same location)

Dispersion Beta functions

More Dy perturbation with 2+10 dipoles

2+10 6+6

2012 2012

2+106+6

XY plane coordinates

Vertical coordinatesWith SBL switch, arrive in similar vertical plane as top of TT20(vertical angle compensated by rolling slightly 2nd H bend family)

A. Geometry with junction cavern • Beam angle about 130 mrad into new tunnel• Access possible between all tunnels (2 vacuum chambers to remove)• Long cavern (35 m)

Junction considerations

Transport? Splitters

B. Geometry with ‘core’• Beam angle about 115 mrad at the tunnel wall• Access along TT20 blocked• Separate access needed for new SBL line

Junction considerations

Splitters

Conclusions to date• 100 GeV LSS2 fast extraction tested: works with low intensity, large

emittance. Still seems feasible. – 440 GeV to test next week from LSS6.

• Switching from near top of TT20 looks possible at 100 GeV– We can use 3x MBS magnets (which need to be built)– May need to slightly rearrange MDLV corrector and BI

• 1 MBE then needs to be removed from TT20– Trajectory can be recovered without (significant) impact on optics– Needs 1(2) new power convertor(s) and recabling for remaining 12 magnets,

into two new families– Vertical realignment needed of 120 m of TT20

• Other switch options/optimisations could also be possible– Coordinates for junction and start of SBL line defined

• Options for cavern or parallel tunnel and core – transport?

Next steps• Extraction from LSS2

– Beam tests on 23rd October for 440 GeV extraction (LSS6 -> LSS2)– Documentation of studies and MD results

• Switch zone– Check of MBE maximum fields – 2.1 T may be OK, which points to 2+10 split

and 400 GeV, but might need magnet tests at 6000 A.– Develop realistic junction civil engineering (cavern better for transport)– Iterate switch if needed to fit CE constraints

• TT20 transfer line– Rematching of present TT20 optics to something more reasonable for low-

loss beam transport– Checks of TT20 aperture with 100 GeV FT beam– Instrumentation inventory and upgrade requirements

• New SBL transfer line– Finalisation of target coordinates needed!– Design of new 100 GeV line (new student just started working with ABT)

Primary beam production: progress - Extraction from LSS2 - Switching from TT20 at 100 GeV

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