4/11/2014 LIU-SPS ABT review1 M.J. Barnes, L. Ducimetiere, T. Kramer, W. Weterings Acknowledgements: E. Carlier, G. Rumolo, B. Salvant, C. Zannini

Content Expected Issues Possible Upgrades Schedule Budget /Spending Profile Manpower/ Resources 4/11/2014 LIU-SPS ABT review2

Expected Heating Issue 4/11/2014 LIU-SPS ABT review3 *: C. Zannini and G. Rumolo, “Impedance model of the new MKE concept”, LIU-SPS Open 'C' Core MKE Extraction Kicker Review, 20/3/2013. **: M. Timmins, A. Bertarelli, J. Uythoven, E. Gaxiola, “SPS Extraction Kicker Magnet Cooling Design”, AB-Note BT (Rev.2) HV Plates Ferrite Silver painted stripes 80°C (measured with PT100s) [ΔT meas =60°C ] corresponds to the ferrite Curie temperature of ~125°C [ΔT actual =105°C]**. Example of estimating ΔT (ΔT est ) for HL-LHC: ΔT est = 33˚C*(105˚C/60˚C)*(1650W/1000W)=95˚C, and assuming a worst-case cooling water temperature of 28˚C  T=123˚C. This is near the Curie temperature of 8C11/CMD5005 ferrite. 25ns data: measured temperature rise from April 2012; 50ns data: measured temperature rise from August 2012.

Ferrite Temperature  MKEs are currently cooled with demineralised water (20-28˚C).  Water cooling allows the MKE to operate with ~twice the beam induced power deposition (ref: AB-Note BT (Rev.2)).  With the expected beam induced power deposition of 1.65kW/magnet for HL-LHC (with the present serigraphy), the estimated (actual) ferrite temperature is:  ~125˚C for 25ns beam (corresponds to the Curie temperature);  ~105˚C for 50ns beam (uncomfortably close to the Curie temperature).  Mixed (12˚C) or chilled (6˚C) water would give a reasonable reduction (up to ~20˚C) in ferrite temperature.  Back of the envelope calculations indicate that increasing the emissivity of the inside of the MKE tanks (as per the MKIs) could result in a significant radiated power (15-25%), further improving cooling of the ferrite – but current tanks could be radioactive, thus difficult to treat.  Samples of CMD10 ferrite have been obtained for evaluation for possible future use in the MKIs: CMD10 has a Curie temperature of ~250˚C. The CMD10 samples have been tested and Oked by the vacuum team. CMD5005/CMD10/CN20, or a mix of some of these, could give a significant thermal operating margin, for the MKEs, for HL-LHC beam. Equivalent to 8C11 CMD10 also has a saturation flux- density (Bs) greater than CMD5005 but has a lower u’ (acceptable for MKIs, but needs to be checked for MKEs) 4/11/2014 LIU-SPS ABT review4

Ferrite Power Deposition 4/11/2014 LIU-SPS ABT review5 For given properties of the ferrite (permittivity and permeability [which are frequency dependent]), the length/overlap of the serigraphy determines the resonant frequency.  Reducing the length of serigraphy from 200 mm to ~180 mm is expected to increase the resonant frequency from 44 MHz to 49 MHz, close to an optimum for 25 ns and 50 ns beams.  The total power deposition is expected to be reduced from ~1650 W to ~850 W for 25 ns beam, and ~1150 W to ~820 W for 50 ns beam: 850 W  80˚C estimated with 28˚C.  Measurements (on a single cell or MKE magnet?) are required to confirm the predictions and hence the optimum length of serigraphy. Measurements on an S-type magnet would leave an L–type spare. 230 mm (length of ferrite block) 200 mm length (presently) Predicted power loss due to serigraphy peak as a function of frequency of the peak (σ=20 cm): 200 mm Courtesy of Carlo Zannini ~70% of total ~60% of total

4/11/2014 LIU-SPS ABT review6 25 ns Ecloud Studies (25/04/12-26/04/12) Ecloud is present in the MKEs with 25ns beam. Possibly coating the, aperture side, surface of the ferrites with Cr 2 O 3 or amorphous Carbon (aC) could eliminate Ecloud: this has not been tried at CERN. aC could suffer from high instantaneous power loss during pulsing, therefore Cr 2 O 3 may be a better option. Could/ should this be tested on an operational MKE or a dummy (retractable) MKE in the SPS?

4/11/2014 LIU-SPS ABT review7 Cost/Manpower: Chiller Chiller: Chiller (variable down to 6˚C) installed in tunnel, with a closed secondary cooling circuit; Disadvantage Condensation issues on magnet feedthroughs to consider (at low water temperatures); Advantages Magnets do not need to be rebuilt. Cost: approximate estimate of 40 kCHF per each of MKE4 and MKE6, including stainless-steel piping; Manpower: 6 person months for design and installation (parallel cooling circuits per extraction, where to put chiller, ….?) If optimized serigraphy is used, a chiller gives additional operating margin for ferrite heating (especially important if σ < 20 cm).

4/11/2014 LIU-SPS ABT review8 Cost/Manpower: Ferrite/Serigraphy New ferrite and/or new serigraphy: 10 MKE magnets MKE4 [3L, 2S], MKE6 [2L, 1S] & 2 spares [1L, 1S]) need to be rebuilt (if MKE4 is kept as per present): 2 less MKEs required for short-circuit configuration. ~3-4 months for bake-out of 10 magnets worth of ferrite to 1000˚C (probably not needed for change of serigraphy length); New ferrite: 231 kg/magnet  45 kCHF/magnet (estimate); Replace large vacuum seals of MKE tanks (~2 kCHF/magnet); Install 2 vacuum valves per magnet: 50 kCHF per magnet (allows vacuum to be broken in SPS ring without having to recondition all magnets) – expensive option…. Total person power for preparation and installation of 2 magnets (not inc. bake-out): With manual pulse conditioning: ~5.5-6 person months before TS + ~1 month in TS; With automatic pulse conditioning: ~4-4.5 person months before TS + ~1 month in TS. (manual conditioning: save ~3 weeks per magnet with automatic conditioning) Technical Stop (TS)

LS 4LS 5Run 5 LS2 starting in 2018 (July)=> 18 months + 3 months BC LS3LHC: starting in 2023 =>30 months + 3 months BC Injectors: in 2024=>13 months + 3 months BC LHC schedule beyond LS1 Beam commissioning (BC) Technical stop (TS) Shutdown Physics (Extended) Year End Technical Stop: (E)YETS Run 2Run 3LS 2 Run 2Run 3 LS 2 EYETS YETS F. Bordry: With only 1 L-type and 1 S-type spare: Only 2 MKEs can be swapped during a YETS (3 months) maybe 3 MKEs during EYETS; e.g. 2 MKE4s during Q1 2016, 3 MKE6s during Q1 2017, 2 MKE4s during Q1 2018, last MKE4 during LS2. With an extra L-type spare (but we do not have spare tanks….): 3 MKEs can be swapped during a YETS (3 months); e.g. all 3 MKE6s during Q1 2016, 3 MKE4s during Q1 2017, last 2 MKE4s during Q /11/2014 LIU-SPS ABT review9

Budget breakdown The following assumes that MKE4 is kept as per present (5 terminated MKEs): 2 less MKEs are required for a short-circuit configuration. Total budget for new serigraphy: ~30 kCHF (including labour for removing end (~20mm) of present serigraphy, cleaning); Total manpower (FSU) for assembly and installation: ~50 kCHF (6 person months); Modify lifting device to reduce radiation exposure of personnel: ~5 kCHF; Total budget for new seals for vacuum tanks: ~20 kCHF; Estimated total budget for Cr 2 O 3 : ~20kCHF; Total budget for chiller system: ~80 kCHF (to be spent ~2018, depending on effectiveness of new serigraphy and/or desired thermal margin). Detailed breakdowns to be done. Total budget for new ferrite type is ~450 kCHF (expensive and not necessary if optimum serigraphy length reduces power deposition to ~850 W, as predicted). Total budget for 2 valves per tank is ~500 kCHF (expensive for gain !). 4/11/2014 LIU-SPS ABT review10

Spending per year in kCHF Year Total ?+3080?+125 Spending Profile for Rebuilding MKEs Cooling option in purple. 4/11/2014 LIU-SPS ABT review11 Following spending profile is: with new serigraphy, large seals for tank, coating of ferrite (e.g. with Cr 2 O 3 ) and new lifting device; without new ferrite, valves or dummy magnet; assumes that MKE4 is kept as per present (5 terminated MKEs). Notes: a)if MKE4 is reconfigured with 3 short-circuit magnets, a total (including spares) of 8 (instead of 10) MKEs are required. This would save ~20 kCHF by reducing the number of MKE4 magnets by two. b)if MKE4 is reconfigured with 3 short-circuit magnets, a 4 th MKE could be installed with 180 mm serigraphy and Cr 2 O 3 : installing sector valves around this MKE would cost ~100 kCHF.

Manpower/Resources For chiller system: 6 person months for design and installation. For rebuilding, testing etc. 10/8 magnets and installing 8/6 magnets: ~ 35/28 person months with manual conditioning; ~ 28/21 person months with automatic conditioning Up to 3 person months for new conditioning system for lab (+ some hardware). No detailed manpower planning available yet Conceivable that additional manpower is needed. Assembly area for magnet and generator will be 867 (within controlled zone). HV-Test cage for system testing is needed /11/2014 LIU-SPS ABT review12

Conclusions Estimates presented for; Reducing length of serigraphy: measurements required (on at least 1 cell, and preferably a full [S-type?] magnet) for confirming impedance predictions; Painting aperture surface of ferrites with either aC or Cr 2 O 3 ; Using a chiller (gives additional safety margin, especially useful if bunch length < 20 cm); Replacing ferrite with a higher Curie Temperature version – expensive and probably not required; Vacuum valves – expensive. But cost estimates and manpower would be impacted by MKE4 configuration (terminated or short-circuit mode). 4/11/2014 LIU-SPS ABT review13

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Reserve slides 4/11/2014 LIU-SPS ABT review15

Beam induced heating estimation 4/11/2014 LIU-SPS ABT review mm serigraphy Courtesy of Carlo Zannini

Beam induced heating estimation 4/11/2014 LIU-SPS ABT review mm serigraphy Courtesy of Carlo Zannini

Cooling test bench: ferrite temperatures at different probe positions Slide information from: SPS Extraction Kicker Magnet Cooling Design M. Timmins, A. Bertarelli, J. Uythoven, E. Gaxiola AB-Note BT (Rev.2) TS-Note DEC (Rev. 2) 4/11/2014 LIU-SPS ABT review18

43˚C 28˚C 23˚C 25 April-26 April, 2012: 25 ns beam Ecloud studies 4/11/2014 LIU-SPS ABT review19 Courtesy of Carlo Zannini

We assume a bunch length of about 18 cm with the 25 ns beam at flat bottom 25 April-26 April, 2012: 25 ns beam Ecloud studies G. Papotti In very good agreement with the measured heating 4/11/2014 LIU-SPS ABT review20 Courtesy of Carlo Zannini

Ref: Glenn Vanbavinckhove, Open 'C' Core MKE Extraction Kicker Review, 20/3/ /11/2014 LIU-SPS ABT review21

Ref: Glenn Vanbavinckhove, Open 'C' Core MKE Extraction Kicker Review, 20/3/ /11/2014 LIU-SPS ABT review22

4/11/2014 LIU-SPS ABT review23 50 ns Normal Operation (15/08/12-16/08/12) Ecloud is not so obviously present for 50 ns beam.