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Summary: LIU-SPS external beam dump review

Summary: LIU-SPS external beam dump review. SPS external dump review. The SPS has compared to other accelerators a rather high beam power and it is among the most powerful proton accelerators worldwide Is motivation clear and sufficient? Are specifications complete, with enough margin?

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Summary: LIU-SPS external beam dump review

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  1. Summary: LIU-SPS external beam dump review SPS external dump review

  2. The SPS has compared to other accelerators a rather high beam power and it is among the most powerful proton accelerators worldwide Is motivation clear and sufficient? Are specifications complete, with enough margin? Are worst-case beams defined, and repeated dumping for extended periods? Margins: design is focused on first phase (incl. HL-HC parameters) using known future beam parameters, what are future upgrade options if parameters will further evolve? Scope of workshop and introduction SCHMIDT, Rüdiger

  3. Need to dump all beams, all energies, all types (E, emittance, I, repetition period) Emergency dump and setting up Start with relevant beam parameters that are known Max intensity and cycle length are important parameters What is the average beam power? This number is most useful to compare different beams. New projects: SHIP with 7.2 s cycle length, LAGUNA, …. 320 bunches for LHC, … should be taken into account … what impact does it have on the current design? Operation scenario (e.g. waiting time between cycles, after an emergency dump) Current dump in LSS1, H and V sweep (V is fast), internal beam dump, injection kickers in same area. Two beam dump blocks, low and high energy, some forbidden zone 28.9GeV-102.2GeV. At 14 GeV high E dump is not sufficient. Bumps are used, depends on optics. Dose close to the beam dump: up to 15-25 mSv/hr 86% of energy is absorbed… where does the rest go? Graphite is open to beam tube…. issues with vacuum pressure spikes (HW interlock) SPS beam dumping: from today to LIU eraVerena Kain

  4. Robustness: repetitive dumping is an issue Limits were 18 shots, 6 s cycle, then wait 5 min (total 408 s, 8.6e14 protons) Limits were exceeded several times per year, no “formal” limit was set Damage with current beam parameters can be avoided by operational procedures / SW interlocks One shot of LIU standard would go above operational limit (this limit went down from 400 C to 200 C) What are the limits? One shot, continuous use. Disadvantages, but in principle ok for beam parameters HW upgrade…. no dead zones where we cannot dump Emergency beam dumps in in forbidden zone (only very few dumps, per mille effect) Improved logging needed How much beam / power could one put on the external beam dump? SPS beam dumping: from today to LIU eraVerena Kain

  5. Issues: prone to water leak, degassing, radioactive in LSS1 During LS1 some refurbishment was done Al debris found during LS1, Al block damaged, pieces of about 1 cm, clear damage, no visible impact on beam operation, graphite block ok Damaged beam dump due to excessive beam load – dumping for extended periods New TIDVG ready by 31 August Some improvements have been done, and some improvements will be done in the future (e.g. temperature sensors) Maintenance with high accumulated dose: training, robotics, design for end-of-life Define beam load: what parameters are relevant? Are there any other beam dumps or TEDs at CERN in a similar condition? List of dumps, and list of parameters….. for all dumps and TEDs. What is the monitoring and recording of data Upgraded internal beam dump for LHC, for what load? Emergency beam dump? Operational issues? What damaged the present beam dump? CNGS very likely above by a factor of two. Status of old beam dumps TIDVG1? Recently observed problems with present TIDVG,Ivo VICENTE LEITAO

  6. Outgassing issue for new dump…. Initially “protected” by vacuum (valves close and stop beam due to high pressure) Damage of upstream part? Nothing seen…. Are different dumps needed? Emergency and operational beam dump: why have not only one external beam dump? Fraction of emergency beam dumps / operational beam dumps Recently observed problems with present TIDVG,Ivo VICENTE LEITAO

  7. TIDV main problem, about 10e18 p/year, severe radiation problems (activation) High dose rate, up to 25 mSv/h after 30 h (one meter from equipment), many consequences Momentum collimator TIDP is next (3 mSv/h) Air activation: release close to Bat. 54 – to public close to 10 muSv/y Air-born radioactivity, tunnel monitors trigger Both could stop SPS (happened in 2004, and might happen again with beam dump that is outgassing) New beam dump should avoid such problems: redesign or external beam dump (external beam dump more promising option) External beam dump: LSS1 will become much cleaner: majority of protons should go out (order of a factor of 10) New beam dump considerations: prompt dose, activation, air Prompt dose: shielding – high E muons go far. Annual muon dose , 550 m concrete to be avoided – not to have a beamline pointing upstream 10 m concrete should be present to avoid controlled area Shielding well defined, molasse could be used Rradiation Protection considerations,H. Vincke

  8. Activation around new beam: no access limitation in the vicinity, concrete shielding of 3 m radius Some operational scenarios: 2e18/yr and 2e18/yr + MD -> acceptable, after one day 1-10 uSv/h Other scenarios if there is too little space, can be optimised, not yet fine tuning. Air activation: prevent immediate air release (consider location) Dose to accelerator equipment: no problem to outside shielded region (cable exchange not required, say, every 10 years) What beams can be dumped? How much fraction of the power? Integrated power is the parameter Momentum collimator TIDP is next (3 mSv/h): can the dose be brought down? Not clear, better when operating without transition Fixed target beam after extraction should be also extracted (few % of beam end of each cycle) Transport of an activated dup: needs to be considered, but can be done… Rradiation Protection considerations,H. Vincke

  9. One shot for each beam dump was calculated Run 2 beam parameters were considered, up to 4e13 protons Sweeping is considered, different for different beams (depends on batch length), is an important factor for one shot, emittance is less of an issue – Run 2 dT increase of 70 C Run 3: dT increase of 170 C Different cores lead to different T Ti – advantages, optimisation still possible Increase of high density graphite? C-C? Difficult to get….adding some other material? For emergency beam dump do not need to stop 80% protons TEDs: dependence of beam spot size. Even more critical…..higher energy deposition, but closed. What would happen? Closed system. Risk to be analysed. What is the impact of melted Aluminum? TED –could we do some monitoring? External dump: beta function of = 1000….1800 m assumed Would be 7 m long if only graphite (dT = 1000 C) Energy deposition considerations for the worst SPS beam scenarios, Genevieve STEELE

  10. For 4 m, up to 800 C in copper, or up to 450 C with longer graphite part Longer graphite absorber could do it Less constraints for any external beam dump Shock waves – 2nd order problem, also if the material close to melting temperature? Plastifying – how does it evolve with time? Energy deposition considerations for the worst SPS beam scenarios, Genevieve STEELE

  11. TIDVG 1 from 2000 to 2004 TIDVG 2 from 2006 to 2014 TIDVG 3 from 2014 to 20xx HL-LHC 4.82 MJ Cooling system cools copper part, cooling of Al depends on the Thermal Contact Conductance Al is limiting factor, bake-out weakens it: Al at 250 C during 350 h decrease yield strength by 68 % dT should not be higher than 150 C Stress less than 77 MPa, elastic, higher plastic Between 250 and 600 C, not clear, above there is melting Plastification can lead to reduced cooling For 10 pulses, cooling to the outside not important, heat capacity and conductivity of Al block leads to cooling of Tmax Plastification happens after a few shots (for new TIDVG) Thermo-mechanical analysis, Florian PASDELOUP

  12. After 47 pulses, temperature reaches 450 C (assuming nominal cooling, too optimistic) Ideas: higher density graphite, other material (e.g. boron nitride) ,eliminate Al and use Ti, improve cooling, … Cooling of Al absorber blocks possible? Not obvious, problems in the past…. Longer SPS cycles? No real gain…. How many pulses to get to melting point? 47 pulses…. Copper block is cooled, should be not problem….. Interesting to understand observed damage mechanisms of Al (not clear how a 1 cm piece of Al could form) Thermo-mechanical analysis, Florian PASDELOUP

  13. Two options: TT61 and TNC (HiRadMat) tunnels: old neutrino tunnel or using HiRadMat tunnel Extraction system can be re-used Some modification of magnets: 4 MBS (larger aperture) instead of 2MBB Vertical bending is an issue: option to use existing tunnel, No access in HiRadMat when extracting in LSS6 Long shielding for muons, 600 m long shielding Or have a horizontal beam path, excavation needed, tunnel of 140 m required, complicated option Other angle, going through surface. What about molasse? Enough shielding? TNC: water activation? Since dump is close to tunnel wall: no issue Very close to HiRadMat – HiRadMat dump to be moved Could there be only one dump? For HiRadMat and the external dump. No. Beam size would be large enough Issues with interlock – beams with same energy Cost is in the order of several MCHF External beam dump option A: branching off from LSS6, Jose ABELLEIRA

  14. Not clear what such external beam dump could Civil engineering difficult, access difficult Dipole magnets could dilute muons Energy and emittance: does beam fit into aperture External beam dump option A: branching off from LSS6, Jose ABELLEIRA

  15. Studies only done for LHC beam types, extend use of such dump going on (e.g. FT 5%) LSS4 dedicated line Tunnel enlargement needed Behind TT40 create a dump line in TI8 MKE.4 could be extended to 21 mus Two versions studied…. with different dilutions Aperture has been studied (emittances for slow extracted beams) CE enlargement is best for CE Enough space for sweepers Order of 5 MCHF without CE (incl. sweepers) What beams can be dumped with what type of systems (Energy, emittance)? Not clear if FT beams can fit through aperture…. some magnets might be too small Better to have only one cross section If we can dump all beams above 150 GeV (LHC), 300 GeV (FT) we would gain a lot, below is 1 % Early dumps could be at higher energy, is this preferred? Possibly… How to do it operationally – operational scenarios…. External beam dump option B: branching off from LSS4,Francesco Maria VELOTTI

  16. Operational scenarios….to be developed. RP prefers TI8, better shielding, muons no problem, air activation better HiRadMat – ventilation system might have to be considered External beam dump option B: branching off from LSS4,Francesco Maria VELOTTI

  17. LIU-SPS external beam dump in LSS4 was assumed Path to access with some distance in several tunnels Several options are being studied Enlargement 68.5 m * 10.5 m wide or 73 m * 10.5 m or 91 m * 10.5 m (concrete and iron shielding) or 83.6 m * 12.5 m (only concrete shielding) Distance between TT41 and new tunnel at least 4.80 m Molasse could be used for shielding Exchange of the dump to be discussed, several options Displacement from TI8 line is fixed Different options: CE cost between 8.9 and 12.6 MCHF (incl. 10% contingency and consultants), uncertainty about 50% 5 years project, CE works could be done during 20 months, some GS resources needed Reinstallation about 6 months… what about operation of Awake? Shielding on the back side needed – not needed, could reduce CE (what about water?), could be faster Civil engineering work, Martin MANFREDI

  18. Can we access the area when no extraction in LSS4 – probably yes, to be studied Shaft PCG8, can it be used? Could be better… Should start soon (consultant and contractor) – begin of 2015 when activities should be done in LS2 Dedicated extraction line: would it be possible? More kickers, expensive, but would be of some advantage…still not to be discarded Extraction kicker in the line… if LHC injection is not permitted, send beam into external beam dump Extra extraction kickers in SPS? The it would be better to build a new system in LSS5. LSS5: SPS performance (e.g. impedance), use of LSS5 for other applications, cost of new system, radiation in LSS5, radioactive zone in LSS5 Civil engineering work, Martin MANFREDI

  19. Motivations for an external beam dump: activation, efficiency of operation (HL-LHC) An external beam dump should be designed to be used for the next, say, 40 years (a least it should be designed such that an upgrade is possible) Beam parameters improved over the last 40 years, a similar improvement is expected for the future Could one external dump use for all beams? Logging of parameters to be improved Summary

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