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Update on Beam induced heating

Update on Beam induced heating. Put together with the invaluable input and help of many colleagues:

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Update on Beam induced heating

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  1. Update on Beam induced heating Put together with the invaluable input and help of many colleagues: Collimation team: Oliver Aberle, Ralph Assmann , Roderik Bruce, Alessandro Bertarelli, Federico Carra, Luca Gentini, Luisella Lari, FredericLoprette, Roberto Losito, Stefano Redaelli, MarcTimmins, Daniel Wollman Cryogenics team: Serge Claudet, Laurent Tavian Kicker team: Chiara Bracco , Mike Barnes, Brennan Goddard, Jan Uythoven RF team: Philippe Baudrenghien, Themistoklis Mastoridis, Juan Esteban Mueller, Elena Shaposhnikova Impedance team: Gianluigi Arduini, N. Biancacci, Fritz Caspers, Hugo Day, Alexey Grudiev, Elias Métral, Nicolas Mounet, Jean-Luc Nougaret, Giovanni Rumolo, B. Salvant Instrumentation team: Rhodri Jones, Mariusz, Federico Roncarolo, Andriy Nosych Operators and OP team Vacuum team: Vincent Baglin, Alexis Vidal, Giulia Lanza, Bernard Henrist, Gregory Cattenoz And the TIMBER team!

  2. Goal of the talk • Follow-up after the overview of the run at the Evian workshop • Input for talk at Chamonix workshop next week

  3. Focus on • Injection kicker MKI • ALFA detector • VMTSA double bellow • BSRT • Stand-alone Q6R5 • Collimators (TCP, TCTVB, TDI)

  4. Injection kicker MKI • Followed up by Hugo Day and Mike Barnes • Xrays on MKI2  not much space, very difficult to observe anything • Xrays abandoned for the moment for MKI8 (MKI8D and to a lesser extent MKI8B are an issue) • Simulations and measurements of longitudinal impedance with different configurations of the RF fingers (talk of Hugo Day at ICE meeting)

  5. Impedance simulation and measurements (24 conductors) H. Day et al

  6. Impedance simulation and measurements H. Day et al

  7. Power loss estimates H. Day et al • Potential changes in LS1 • To be continued

  8. Focus on • Injection kicker MKI • ALFA detector • VMTSA double bellow • BSRT • Stand-alone Q6R5 • Collimators (TCP, TCTVB, TDI)

  9. Courtesy Sune Jakobsen et al Beam intensity Temperatures in 7R1 Temperatures in 7L1 Beam energy • Detector temperature should not increase by more than 40 degrees • Temperature increased by max 18 degrees in 2011 • interesting to note that the temperature increase started already at injection

  10. ALFA detector • Followed up with S. Jakobsen, P. Fassnacht, F. Caspers and E. Métral • Simulated power losses due to impedance of the order of 15 W could be consistent with the observed temperature increase (bench measurements) • Need to decide if the detector should be taken out • Cooling and RF damping system planned to be modified in LS1 (as for Totem)

  11. Focus on • Injection kicker MKI • ALFA detector • VMTSA double bellow • BSRT • Stand-alone Q6R5 • Collimators (TCP, TCTVB, TDI)

  12. VMTSA • Followed up with J.L. Nougaret, V. Baglin, A. Vidal, B. Henrist, G. Cattenoz, F. Caspers, E. Metral • Large temperature increase inside the bellow indicated by melting of the fingers • Up to now, simulations and measurements indicate that the design VMTSA should not generate significant heating, but runaway effect is feared. • New design with shorter fingers is being installed and is expected to help. • Need to check with RF measurements followed up by Jean Luc, Elias and Fritz Pictures TE/VSC/LBV

  13. Focus on • Injection kicker MKI • ALFA detector • VMTSA double bellow • BSRT • Stand-alone Q6R5 • Collimators (TCP, TCTVB, TDI)

  14. BSRT mirror system • Followed up with A. Nosych and F. Roncarolo • Federico observed that the beam spot is consistently moving when beam intensity is increased and coming back when intensity decreases • beam induced heating of the mirror or of the holder? • Can it damage the system? • First simulations by Andriy show a significant mode that could cause power loss  first discussions yesterday, to be continued

  15. Focus on • Injection kicker MKI • ALFA detector • VMTSA double bellow • BSRT • Stand-alone Q6R5 • Collimators (TCP, TCTVB, TDI)

  16. Q6R5 standalone • Follow up with L. Tavian and S. Claudet • Xrayswereperformedaround the valve: no obviousmetallic obstruction. • In particularneed for a measurement of pressure at the input of the valve as a capillarycouldobstruct the entrance. • TE/VSC/LBV performedXrays on Dec 16 on the RF fingers in the bellows in that zone : Nothingspecialisobserved • 13553.366 a 13554.001 (4 soufflets) • 13562.27 a 13562.905 (4 soufflets) • Interesting to note that TOTEM roman pots are 3 m away. However, warm region so it should impact.  Need to wait for LS1 to open and diagnose.

  17. Focus on • Injection kicker MKI • ALFA detector • VMTSA double bellow • BSRT • Stand-alone Q6R5 • Collimators (TCP, TCTVB, TDI)

  18. Collimators • followed up with Oliver Aberle, EN/STI, and EN/MME • TCP.B6L7.B1  nothing obvious for that primary, Xrays next week • TCTVB.4R2  has been removed during the stop  should nevertheless check the collimator in storage for potential issues • TDI  opened to check the Ti coating  deformation of the beam screen observed (follow up also with TE/ABT)  beam induced heating could be one of the causes, investigated by Alexej Grudiev and Delio Duarte Ramos (ongoing)  phase error measurement during an MD indicate an increase of losses of the order of 1 to 2 kW when closing the TDI jaws fromparking to 3.7 mm half gap.

  19. Phase error measurement with single bunch With Gianluigi Arduini, Chiara Bracco, Juan Esteban Mueller, Elena Shaposhnikova et al 0.1 degree Phase error TDI full gap 40 mm

  20. From phase shift to power loss With Juan Esteban Mueller, Elena Shaposhnikova et al • Energy gain per particle: • Energy gain per particle when moving the TDI out: • Power per particle when moving the TDI out : • Power per bunch when moving the TDI out : In the case of the MD: Note: empirical error bar to give order of magnitude of noise

  21. Extrapolation from the MD to nominal 50 ns beam (with E. Metral) • Power loss from impedance for M bunches • Power loss from impedance for a single bunch If for the studied modes (i.e. Q < 900 for 10 MHz, Q < 90000 for 1 GHz) In most cases, the sum can be approximated by an integral for for high Q modes in the case of single bunch In most cases, the sum can not be approximated by an integral for high Q modes in the case of multibunch As a consequence for a given mode, scaling can be applied with bunch intensity: But scaling is not obvious with number of bunches:

  22. Phase error measurement with almost filled machine (except the last batch) – 50ns intensity Phase error 0.1 degree TDI full gap With Stefano Redaelli, Juan Esteban Mueller, Elena Shaposhnikova et al Power lost by the full beam when moving the TDI out : In the case of the MD: Note: empirical error bar to give order of magnitude of noise

  23. Tentative scaling to 1380 bunches at 1.5e11 p/b - From single bunch MD  ~1.6 kW • From 1236 bunches MD  ~1.3 kW • Assuming broadband impedance can give an order of magnitude, but may be very off compared to the actual power deposited. However in this case, this scaling is consistent  TDI is abroadband impedance? • To be checked in measurements in physics (if possible…). • Need to gate the phase error per bunch to decrease noise (Juan and Elena)

  24. Actions for the impedance team • Injection kicker MKI  simulate RF fingers • ALFA detector • wire measurements • Predict effect of bunch length • Help with system improvement in LS1 • VMTSA double bellow RF measurements and simulations with smaller fingers in conform and non conform situation • BSRT • Assess heat load on the mirror and on the holder • Stand-alone Q6R5 • Collimators (TCP, TCTVB, TDI)  assess heat load on TDI from simulations  check the deformation of the shielding foil behind the beam screen before and after the jaw  check the TCTVBs taken out of the machine Other actions?

  25. Thank you for your attention

  26. Power loss estimates vs bunch length for 50 ns H. Day et al

  27. Juan (MD single bunch)

  28. Juan (MD multi bunch)

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