Crab Cavities Vacuum Aspects Compatibility with COLDEX Running
Crab Cavities: Vacuum Aspects & Compatibility with COLDEX Running V. Baglin (TE-VSC) on behalf of WP 12 Crab Cavity SPS Tests Day I CERN – 11 th January 2016
1. Crab Cavities bypass in SPS BA 6 WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 2
SPS LSS 6 – Half period QDA 61710 – QFA 61810 VVSB TPSG VVFA MST WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 3
Pressure profile • Actual pressure in the sector ~ 2 10 -8 mbar: dominated by pressure at sector valve WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 4
• • Pressure profile: Zoom Actual pressure in the sector ~ 2 10 -8 mbar: dominated by pressure at sector valve ZS = 2 10 -9 mbar TPSG = 3 10 -9 mbar MST = 2 10 -9 mbar One order of magnitude must be gained to reach the specs : 10 -10 mbar in CC WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 5
SPS vacuum chambers: QDA • Computing electron cloud levels in QDA type chambers would be beneficial WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 6
A Minimal Instrumentation Layout CC • 4 vacuum sectors: • Upstream CC, NEG coated • CC • Downstream CC, NEG coated • Bypass, NEG coated • Each vacuum sector has: • Penning / Pirani gauges • Roughing valve • NEG coated sectors have: • Ion pumps Detailed study is needed to optimise the pumping scheme More instruments could be added WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 7
Conceptual Hardware Layout around CC V 1 nc 16 o r a n i V 2 t p e lim e r P • Y chamber • Impedance free • NEG coated • Number of cycles for the bellows ? • Bypass chamber • Distance between mechanical axis bypass-CC : 510 mm o c y V 3 V 4 R. Calaga, 27/10/2015 • Crab cavity volume • L = 3000 mm • W = 1100 mm • Sector valves, V 1, 2, 3, 4 • Fixed to the movable table Is available longitudinal space of ~ 9. 5 m enough ? WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 8
New Sectorisation • The assembly sector valve plus fast valve must be moved towards the right side by ~ 5. 5 – 6 m • ECR needed • Fast valve might be completely removed from the layout if needed • The chamber VEWJ can be even reduced in length (pending aperture checks) if needed WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 9
Installation • Planned in 2 phases during EYETS 2016 -17 and YETS 2017 -18 • Needed definition & procurement • Vacuum sectorisation & instrumentation • Y chambers need frozen specification by Dec 2015 • Procurement of main components : sector valves (6+1), pumps, gauges etc. . • Intervention planning to be detailed: • EYETS 2016 -17: • Venting the 2 adjacent sectors with N 2 • Immediate installation of the external sector valves to allow pump down of the adjacent vacuum sectors (ZS tank , Graphite TPSG, Septum …) for creation of a new vacuum sector • Installation of SPS standard pipe in the new sector • YETS 2017 -18 • Venting and removal of SPS pipe • Installation and closure of the CC bypass system (with a replacement chamber if CC not available) WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 10
CC Test Specifications • Location SPSBA 6 • Half period QDA 61710 • Schedule: • New SPS sectorisation by EYETS 2016 -2017 • Bypass installation during YETS 2017 -2018 • Operates during LHC technical stops • Beams: • Low intensity, single nominal bunch then multi-bunch (4 x 72 b) • What is the expected electron cloud level ? • Vacuum level: • ~ 10 -10 mbar WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 11
2. COLDEX WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 12
Specifications • Simulation of a LHC & HL-LHC cryogenic vacuum system to study the impact of proton beams on the vacuum system • Cold bore 3 -4. 5 K and RT • Beam screen from 5 to 120 K and RT • Vacuum gauges, electrometers, heat load, solenoids • a-C coating, Laser Engineered Structured beam screens. . • Location SPS BA 4 • Use of a bypass system • Aperture restriction not compatible with extraction to TT 40 (LHC and CNGS), operation not compatible with LHC PHYSICS beam (time to move from IN to OUT) WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 13
Specifications • Beams: • LHC & HL-LHC beams and filling scheme • Multi-bunch (only), nominal current & emittance, 26 Ge. V and 450 Ge. V acceleration • Specific studies: • vary number of bunches/train, • vary intensity/bunch • Schedule: • Parasitic during SPS scrubbing run (accumulated beam time to observe long term behaviour and during multi-bunch MDs other than COLDEX dedicated • Dedicated MDs along the year during LHC technical stops: today 24 h MD in 2 -3 blocks but 56 MDs of 12 h per year are preferred WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 14
3. Summary WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 15
Summary • SPS layout with crab cavities needs to be validated by mid-2016 to complete design and start procurement of components • Installation is foreseen in 2 phases: • New SPS sectorisation by EYETS • Bypass by YETS 2017 -18 • COLDEX studies: • Parasitic during scrubbing runs and multi-bunch MDs (e. g. for CC). • Dedicated during specifics MDs (5 -6 of 12 h / year are preferred) WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 16
Thank you for your attention
Spares slides WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 19
SPS Long Straight Section 6 WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 20
SPS LSS 6 – Half period QF 61610 – QDA 61710 VVSB ZS WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 21
SPS LSS 6 – Half period QDA 61710 – QFA 61810 VVSB TPSG VVFA MST WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 22
SPS LSS 6 –ZS WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 23
SPS LSS 6 –QDA 61710 WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 24
SPS LSS 6 – RF testbed area WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 25
SPS LSS 6 – Sector and Fast Valves located in RF test bed area WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 26
SPS LSS 6 – Sector and Fast Valves located in RF test bed area WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 27
SPS LSS 6 – New Position of Sector and Fast Valves WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 28
SPS LSS 6 – TPSG and MST WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 29
SPS LSS 6 – TPSG WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 30
SPS LSS 6 – MST WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 31
Description • QDA 61710 • A defocussing quadrupole, length 4011 mm • Vacuum chamber VEQA, elliptical • VVSB • Aperture 150 mm • A sector valve • It must be displaced and moved on the right side by at least xx meters • VVFA • Aperture 150 mm • A fast valve which protects an unknown device !! • It must be displaced and placed to at least xx meters upstream to the protect equipment • TPSG • A graphite mask which protects the downstream septum • Must be vented, isolated with a new sector valve, (baked ? ) and pump down for at least 4 weeks before beam • Pumping system • On the right side of QDA 61710: a 20 l/s ion pump, VPIAA • At 61753, another a 20 l/s ion pump, VPIAA • At the level of the TPSG, 61772, 2 ions pumps of 400 l/s each, VPIB WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 32
• • • • Pressure profile VGHB_61693: 1. 6 m left of QDA 61710 VPIA_61731: right of QDA 61710 VVSB_61736: sector valve VGHB_61736 VVFA_61737: fast valve VPIA_61737: VPIA_61753 VPIB_61771: on left side of TPSG 61773 VPIB_61772: on left side of TPSG 61773 VGHB_61775: TPSG 61773 VGHB_61778: TPSG 61776 VPIB_61792: on right side of MST 61779 VPIB_61793: on right side of MST 61779 VGHB_61693 VGHB_61736 VGHB_61778 VGHB_61793 VGHB_61775 VPIA_61695 VPIB_61771&72 VPIA_61731 WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 33
• • • • Pressure profile VGHB_61693: ZS tank left of QDA 61710 VPIA_61731: right of QDA 61710 VGHB_61736: on VVSB_6173 sector valve VVFA_61737: fast valve VPIA_61737: VPIA_61753 VPIB_61771: on left side of TPSG 61773 VPIB_61772: on left side of TPSG 61773 VGHB_61775: TPSG 61773 VGHB_61778: TPSG 61776 VPIB_61792: on right side of MST 61779 VPIB_61793: on right side of MST 61779 VGHB_61693 VGHB_61736 VGHB_61778 VGHB_61793 VGHB_61775 VPIB_61771&72 VPIA_61695 VPIA_61731 WP 12 - Crab Cavity SPS Tests Day 1 – CERN – 11/1/2016 34
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