1. B.Goddard for the LIU-SPS team
SPS Upgrade Plans
B.Goddard for the LIU-SPS team
List of actions and planning of implementation
Studies
Impact on other users
SPS performance for LHC and other users in the different scenarios
Potential risks
The invaluable input from E.Shaposhnikova, G.Rumolo, M.Meddahi, R.Garoby, K.Cornelis, J.M.Jimenez, M.Taborelli, E.Montesinos, Y.Papaphilippou, W.Höfle, L.Jensen, T.Bohl, R.Losito, M.Arruat M.Gourber-Pace, S.Mathot , H.Bartosik, D.Manglunki and all other members of the LIU project is gratefully acknowledged.

2. Overview Targets and assumptions Baseline hardware modifications
Design studies
Key milestones, decision points and planning
Technical issues
2012 MD and activities
Expected performance potential for LHC and other users
Potential risks
Ions
Conclusion

3. p+: Targets from HL-LHC
Target: fb-1 per year
O.Brüning, HI-LUMI event November 2011

4. Extracted from SPS Requires slightly more: LHC losses and blowup
2.2×1011 p+/b in 2.3 mm at 25 ns
3.6×1011 p+/b in 2.7 mm at 50 ns

5. Assumed deliverables from SPS
For 2012
Towards ultimate intensity for 50 ns, in smaller than nominal emittance
Nominal intensity for 25 ns, in nominal emittance
Studies above ultimate intensity with 50 ns
Studies with small emittance, nominal intensity for 25 ns
Period LS1-LS2
Towards lower emittances for nominal intensity for 25 ns
Towards lower emittances for twice nominal intensity for 50 ns
Period LS2-LS3
Recover pre-LS2 performance in Y(LS2+1)
Towards 2.3x1011 p+/b and 3.2 mm emittance for 25 ns beams
Towards 2.7x1011 p+/b and 2.7 mm emittance for 50 ns beam
Studies with lower emittances/higher intensities
After LS3
Approach HL-LHC requirements for both 25 and 50 ns beams

6. Planned baseline upgrades
Double power of 200 MHz RF system (LSS3, BA/BB3);
Electron cloud mitigation – in-situ aC coating of all dipole and quadrupole vacuum chambers;
Major upgrades of MOPOS and BLMs, plus other new or upgraded BI systems;
New High Bandwidth transverse feedback system;
Upgraded pickups for present high power damper system;
Upgraded passive protection devices in extractions and transfer lines TI 2 and TI 8 (relocation plus new devices);
Improved vacuum sectorisation – arcs and near critical equipment;
Complete the impedance reduction of MKE and dump kickers.

7. Studies and decision dates
Full review of ecloud mitigation option: end 2012
Review measurement, technology and simulations
Decided and endorse full aC coating of machine
Change to low gamma-transition Q20 optics: end 2012
May need extra bumpers for LSS1 injection chicane
New scraper design study: end 2012
Localise losses and improve reliability
New MKE/extraction study/prototyping: mid 2013
Further reduce kicker impedance with totally
new kicker and extraction design
Beam dump design study/prototyping: mid 2013
Safe absorption of higher brightness beams
Removal/mitigation of operational limitations

8. LIU-SPS related consolidation
MOPOS and wirescanner consolidation
Take into account LIU-SPS requirements, shared resources
MKDV switch and generator consolidation
Coordinate with eventual beam dump upgrade
200 MHz driver/controls & Faraday cage consolidation
Coordinate with 200 MHz upgrade, LL upgrades
800 MHz upgrades
Coordinate with beam dynamics needs and 200 MHz upgrade
Possible main dipole coil consolidation
Coordinate with aC vacuum chamber coating
Other high impact consolidation activities to consider
LV/control recabling campaigns
Infrastructure work

9. Assumed constraints and planning
Constraints (working assumptions)
Injectors OFF in 2013, for 12 months
Injectors OFF in 2018, for 12 months (min. for SPS 200 MHz)
PSB H- injection
could be available
to install
SPS aC coating, 200 MHz
upgrade completed
IEFC WS 2012
Linac 4 ready
LS1 for injectors
LS2 for injectors
2012
2013
2014
2015
2016
2017
2018
2019
commissioned
Injectors

10. Outline of LIU-SPS planning
LS1
LS2

11. Outline of LIU-SPS planning
LS1
LS2

12. Technical issues and progress
ecloud – amorphous carbon coating
Feasibility of Hollow Cathode method demonstrated in 2011
Confidence in lifetime, handling and static vacuum behaviour
Treatment of vacuum chambers inside magnets – no magnet opening
Definition of extra sectorisation completed
For 2012, explain dynamic pressure rise (test zone installed)
Beam induced heating/outgassing of components
Still limitation for high duty factor MD/LHC filling cycles
Complete MKE serigraphy should help (after MKE conditioning...)
Reviewing general impedance reduction (kickers & other elements)
200 MHz: good progress with building, services and amplifiers
Shorter main couplers needed to fit new layout in LSS3
Design needs to be launched, prototyped and validated
Transverse damper relocation to LSS3 not possible. Stays in LSS2.
No space available with 200 MHz rearrangement

13. Technical issues and progress
Beam instrumentation
Specifications for upgrades being defined (dynamic ranges, bunch by bunch, presently foreseen upgrades/new instruments, LIU requirements)
Half-day review of BI deliverables with LIU plus experts (April 2012)
OP and other SPS users requirements being taken into account
Dump limitations for MDs and high duty factor operation
Outgassing of TIDVG affecting MKP, and forbidden zone
Extra differential pumping and sectorisation planned
Not very strong limitation for LIU – to be studied in
Exit windows and TEDs
Intensity/transverse emittance limits to be defined (I, e)
Compensation of injection doglegs for Q20 optics
Test of principle in 2012; finalise requirements for any additional bumpers
High bandwidth damper development
Need to demonstrate closed-loop and damping of head-tail instability in 2012
Then specification and prototype construction (HBW pickups and dampers). Short timescales to be ready for end 2014.

14. MD studies for 2012 Scrubbing tests in week 13
Key question: can we scrub SPS below SEY 1.3; can scrubbing replace coating?
Efficiency of scrubbing with uncaptured beam
Most interesting techniques not available (5 ns or ns spacings from PS)
Monitor and qualify scrubbing under different beam/chamber conditions
Validate simulation models on scrubbing times (like for LHC)
Some new setups for validation of aC coating
Beam dynamics and beam quality
Q20 optics deployment
Q20 beam transfer, including injection into LHC
Longitudinal instabilities in a double RF system
Split tunes (20, 26), coupling correction
Instabilities (TMCI, ECI)
Space charge and working point studies
PS-SPS transfer studies
High bandwidth feedback (close feedback loop and damp head-tail modes)
Impedance identification
Emittance preservation (across injector complex and LHC)
Some optimisation of MD time proposed with respect to 2011
MD follow-up meetings and prioritisations in frame of SPSU-BD WG
More frequent (shorter) MD blocks  more continuous effort on Q20 optimization
5 day dedicated block for scrubbing studies

15. Expected performance potential
Longitudinal instabilities & beam loading: after upgrade, expect factor 2 intensity possible w.r.t. 2011
2.3×1011 p+/b for 25 ns, and >3.4×1011 p+/b for 50 ns
Main unknown is beam stability with high intensity (combination of single- and coupled-bunch effects)
ecloud: should be solved after LS2 with aC coating of main magnets
HBW feedback could help fight against vertical ECI
Heating of extraction kickers: should be solved after LS1
Expect limit to be at least twice present beam power (2.3×1011 p+/b for 25 ns)
Outgassing of dump and impact on injection kickers MKP vacuum
Effect mainly limitation for scrubbing and setting up, rather than LHC filling
TMCI
Measured to be above about 3.5×1011 for single bunch on Q20 optics
HBW damper as possible additional mitigation
Space charge limits
Expect to be able to exceed DQv of -0.15: 3.5×1011 p+ in 2.8 mm emittance

16. Expected situation after upgrade
If all upgrades work as planned, SPS fairly well matched to requirements
SPS should not be a limit for 25 ns beam for HL-LHC
Need to increase DQv above towards -0.2 for 50 ns beam

17. Upgrade impact on other users
Mandate is to “not reduce performance for other users”
No negative impact on any other users identified to date
Many positive effects expected:
Extra RF 200 MHz power
New/upgraded beam instrumentation (other beams being considered in specifications)
Vacuum sectorisation
Impedance reduction
HBW feedback and damper upgrade
Possibly also Q20 or split-tune optics

18. Risks and concerns ZS sparking (LSS2 electrostatic septum)
Interference with slow extracted FT beams;
Difficult to solve – ‘ppm’ main voltage modulation being studied;
Test ZS tank in LSS6 – now equipped with extra impedance shielding; measurements to make in 2012;
Last resort would be ZS off and retracted during LHC beam, which strongly impacts beam to North Area.
Dynamic vacuum behaviour of aC coating
16 m test chambers just installed; studies in 2012 to answer this
Unexpected problems with heating of other elements
New study/analysis to be made in 2012 using updated beam parameters
Planning of LS2 ‘big bang II’ shutdown
Already concern about accumulation of activities (e.g. magnet coating and LSS3 RF 200 MHz) – planning starting
Project resources – securing manpower
Large ramp-up in activity and spending needed from 2013 onwards

19. Key 2012 LIU-SPS activities
200 MHz upgrade
Civil engineering studies: in progress
Amplifier market survey: launched
New main coupler: to start
ecloud: prepare for aC coating in LS1 (4 half-cells)
Industrialisation of aC on MBA chambers: continuing
Answer question of dynamic pressure rise: in progress
Kicker impedance reduction/ beam induced heating
Preparation (serigraphy) of final 1 MKE: in progress
Impedance/heating review and benefit analysis: to do
High bandwidth feedback
Closed-loop damping studies and design report: to complete (LARP)
Existing transverse feedback upgrade
Technical specification on new pickups: to define
BI upgrades
Specifications with BI group and experts: to finalise following specification review, to have clear milestones for LS1 and LS2
Implementation: to start
Transfer line protection systems upgrade
Design study: in progress
Other design studies
New scraper: in progress
Beam dump, new MKE/extraction: to start
2012 MD

20. Ions Production scheme moved away from original ‘bunchlet’ baseline
IBS and space charge effects less serious than anticipated
Focus is now on increasing number of bunches for Pb-Pb
50 ns bunch spacing
Rise time of SPS injection kicker MKP to be minimised – possible upgrade?
Issues in SPS also include RF Noise, IBS & DQ on flat bottom
First batch suffers 40 more seconds on flat bottom: lower intensity/bunch, transverse emittance blowup
Ions also being considered explicitly in all BI upgrades
New ion species also to be considered: Ar, deuterium
LLRF may require some upgrade

21. Conclusions LIU-SPS upgrade baseline well defined for p+
Majority of work in tunnel for LS2
Implementation started for RF 200 MHz system
Other technical aspects progressing reasonably well
Co-existence with other activities and consolidation work to organise and manage carefully
LS2 shutdown planning a key aspect: possible bottlenecks like transport to investigate
Main planning defined to 2019
Some changes inevitable as progress/delays/design choices occur
2012 key activities identified
Performance potential from upgrade
For LHC, approaches HL-LHC requirements but does not yet meet them
For other users, will be positive in many respects
Risks and concerns
ZS sparking, understanding of aC coating vacuum behaviour, beam induced heating, LS2 planning, adequate manpower

22. the end

23. Known limitations
E.Shaposhnikova, Chamonix 2011

24. ecloud mitigation HC sputtering to deposit amorphous carbon (aC) layer
Large reduction of SEY below ecloud threshold
Coating in dedicated workshop (ECX5) 4-6 magnets per day

25. SPS longitudinal instabilities
Longitudinal stability: 25 ns beam unstable at 2-3e10 p+/b
Presently mitigated with long. emittance blowup (0.6 eVs) and 800 MHz
Need 0.9 eVs for 25 ns stability with twice nominal Ib (Q26)
Maybe gain from lower impedance (200 MHz and kickers), x2 800 MHz V
Would be very beneficial to transfer longer (e.g. 1.8 ns) bunches to LHC (but need to mitigate capture losses in LHC) -> MD studies needed
Q20: instability thresholds higher, but need smaller el to get same bunch length for given VRF
After upgrade, expect factor 2 intensity possible wrt 2011
2.3×1011 p+/b for 25 ns, and >3.4×1011 p+/b for 50 ns
Main unknown is beam stability with high intensity (combination of single- and coupled-bunch effects)

26. SPS beam loading
SPS 200 MHz: x2 power, 46 (shorter) cavities, -20% impedance
Will allow 10 MV at extraction for 3 A RF current (now 1.5 A)
Need to operate existing power plants in pulsed mode (0.751.05 MW)
After upgrade: same voltage available as now (if pulsed) for 2.3e11 p+/b (25 ns) and 4.6e11 p+/b (50 ns).
With larger emittance more VRF needed for same bunch length
Will anyway have 10% longer bunches for 2x nominal I, with 10 MV
E.Shaposhnikova

27. RF 200 MHz reorganisation
Increase power to 6 MW into 6 shorter cavities (from present 4) to give 10 MV required at ultimate intensity
Needed for longitudinal stability (increase emittance from 0.6 eVs)
Reduces impedance by 20%
Big job: new BC3 building, new LSS3 layout, 26.5 MCHF over 7 years