PSB Finemet upgrade: overview, preliminary results & planning LLRF: M. E. Angoletta, A. Findlay, M. Jaussi, J. Molendijk, J. Sanchez Quesada (RF/FB, RF/CS) HLRF: M. Paoluzzi, M. Haase, A. Jones (RF/IS) PSB simulations: D. Quartullo, S. Albright (RF/BR) MSWG, 24 April 2015

Outline 1.Project overview MDs results 3.Plans for 2015 & MD requests 4.Conclusions 5.References

Outline 1.Project overview MDs results 3.Plans for 2015 & MD requests 4.Conclusions 5.References  Why & what  2012 MDs  Installations after LS1  Finemet Review Sept 2014

Project overview: why & what [4]  2010: new low-loss Finemet material (FT3L) [4]  Aim of the project: to evaluate if it is possible to replace C02 (S7+S10) + C04 (S13) with Finemet-based cavities. M. E. Angoletta “PSB Finemet upgrade” MSWG 24/04/  Operation to be assured for 25 more years.  Increased beam intensity (2E13 ppb)  Increased injection + extraction energies  C04 HLRF is limiting system Upgrade: Linac4 +  Wide-band cavities: beam loading compensation needed (fast RF + LLRF feedback)  Each Finemet HLRF (12 cells) used as C02 + C04  Options: 2 straight sections → 16 kV 3 straight sections → 24 kV [1][2,3]  PSB HLRF: consolidation [1] + upgrade [2,3] needed

[5] Project overview: 2012 MDs [5] [6]  HLRF [6] : 5-cells installed in Ring 4 (S6), 4 cells (~ 2 kV) for final tests.  LLRF: Servoloop on one harmonic (LEIR-based test system.)  Operation: acceleration of h=1 beam with C02 + Finemet.  Final result: 460 E10 protons (~6A) with 2 kV Finemet. Problems/limitations:  HLRF:  Limited total voltage available  Radiation effects on solid-state ampli  Limited amplifier diagnostics Solved during LS1 M. E. Angoletta “PSB Finemet upgrade” MSWG 24/04/  LLRF: only one harmonic servoed (processing power limitation) Magnetic field Finemet voltage (2 kV) Beam C02 voltage (5 kV to 1.5 kV, non linear scale)

Project overview: installations after LS1  HLRF: 5 additional cells installed in Ring 4 (S6). Now: 10-cells, 7 kV available in total. [7]  LLRF [7] : New DLLRF operational in PSB. Ring 0 DLLRF used for Finemet tests M. E. Angoletta “PSB Finemet upgrade” MSWG 24/04/2015 3

Project overview: Finemet review (Sept ‘14)  External reviewers: C. Ohmori (KEK), J. M. Brennan (BNL), R. Gaillard (radiation effects consultant)  Strong case for upgrade to Finemet  LLRF adequate  PSB longitudinal dynamics simulations must be improved to extrapolate to future beams (intensity, energy) M. E. Angoletta “PSB Finemet upgrade” MSWG 24/04/  Conclusions for PSB  Conclusions for PSB:

Outline 1.Project overview MDs results 3.Plans for 2015 & MD requests 4.Conclusions 5.References s  Cavity servoloop effectiveness  Acceleration with Finemet alone  Finemet as C02  Finemet as C04  Finemet as C02+C04 & heating tests  simulation

[8] 2014 results: cavity servoloop effectiveness [8]  4 servoloops implemented (h=1,2,3,5)  475E10 protons, h=1 beam.  Reduction in detected voltage with/without cavity servoloop:  No optimisation yet. Voltage induced by 730E10 protons (h=1 beam, NORMHRS, C02+C04+C16) as measured on h=1..6 by DLLRF. M. E. Angoletta “PSB Finemet upgrade” MSWG 24/04/2015 5

[8] 2014 results: acceleration with Finemet alone [8]  7 kV on Finemet alone (no ferrite cavities ON)  650E10 protons accelerated.  Phase loop closed on Finemet gap return.  end acceleration, can be cured with C16. M. E. Angoletta “PSB Finemet upgrade” MSWG 24/04/2015 6

[8] 2014 results: Finemet as C02 [8]  Finemet aligned with C02 (frequency-dependent rotation)  7 kV 2.4 kV C02; 8 kV C04  ~800 E10 protons accelerated on average.  Phase loop closed on C02 gap return. M. E. Angoletta “PSB Finemet upgrade” MSWG 24/04/ Signal voltage envelopes during whole cycle. Yellow trace: driving voltage; Green trace: gap return voltage Double-harmonics effects is clearly visible.

[8] 2014 results: Finemet as C04 [8]  Finemet aligned with C02 (frequency-dependent rotation), programmable phase for bunch shaping  7 kV 8 kV C02; C16 blowup.  ~790 E10 protons accelerated on average. M. E. Angoletta “PSB Finemet upgrade” MSWG 24/04/ (before synchro) 824E10 protons

[8] 2014 results: Finemet as C02+C04 & heating tests [8]  Finemet aligned with C02 (frequency-dependent rotation), harmonic 2 programmable phase for bunch shaping  3.5 kV 3.5 kV 4.5 kV C02; 4.5 kV C04; C16 blowup.  ~800E10 protons accelerated.  For ~1 hour Finemet MD cycles added to supercycle: duty cycle from 8% (3 out of 38) to 68% (26 out of 38).  VRF151 case must remain < 90 degrees and it’s OK also extrapolating to 100% duty cycle. Amplifiers heating tests M. E. Angoletta “PSB Finemet upgrade” MSWG 24/04/2015 9

2014 (+ 2015) results: simulations  BLOnD: Beam LOngitudinal Dynamics simulation code (under development): treats multiple RF systems, intensity/energy effects, acceleration, multibunch…  Aim: to simulate longitudinal stability thresholds with/without Finemet, for higher beam intensity and for higher energies than those now available in the PSB.  Simulations Finemet review in Sept 2014 were limited (no phase loop, injection and extraction simulated with no ramp). [9, 10]  In 2015 the code has evolved [9, 10] and is now able to simulate quite realistically the PSB longitudinal dynamics. [11]  Already one MD of data taking (Ring 3) in March 2015 [11]. M. E. Angoletta “PSB Finemet upgrade” MSWG 24/04/

Outline 1.Project overview MDs results 3.Plans for 2015 & MD requests 4.Conclusions 5.References  Plans for 2015  Questions to be answered  Summary of MDs requirements

Plans for 2015  Finemet program to be completed by mid-Sept  Final Finemet review will take place on Sept 14,  BE management to take decision on Finemet upgrade by Dec ‘15.  Is the system reliable  Can the system handle high intensity beams  Is the longitudinal impedance compatible with future PSB intensity & energy Answers needed to decide on Finemet upgrade: M. E. Angoletta “PSB Finemet upgrade” MSWG 24/04/

Plans for 2015 – reliability validation Question: is the system reliable?  Reliability run with Isolde-type user by using DLLRF Ring 0 + Finemet as C02+C04. How we will get the answer:  Parallel MDs to setup the beam & normal operation for reliability run.  In case of problems, operators will revert to standard operation with Ring 4 DLLRF (no Finemet operation, only ferrite HLRF) via software switch.  Aim: to have the beam ready by next Thursday & start reliability run in May. Not an easy task:  Dedicated MD operating the Finemet HLRF on all users (½ to 1 day).  2014 Finemet cycle settings deleted – had to be recovered from IT database.  Changes in driving chain require new loops and rotation settings  Problems in updated firmware solved this week. M. E. Angoletta “PSB Finemet upgrade” MSWG 24/04/

Plans for 2015 – high intensity validation Question: can the system handle high intensity beams? How we will get the answer:  Parallel MDs with very high intensity beams & LLRF servoloops at additional harmonic (8 or more).  Aim: from June 2015 onwards. We need to maximise the intensity (1E13 protons?) & beam loading as much as possible. How? Beam shortening? Something else? Suggestions anyone? M. E. Angoletta “PSB Finemet upgrade” MSWG 24/04/

Plans for 2015 – long. impedance validation Question: is the longitudinal impedance compatible with the final PSB intensity & energy? (→ inputs for simulations) How we will get the answer:  Parallel MDs with high intensity beam (Finemet MD “Isolde beam” clone).  Data to acquire: bunch length, beam profiles, distribution in phase space, particle loss diagrams, Oasis signals…  Switch between Finemet / no Finemet operation.  Alternation between data acquisition and offline data processing + simulation to compare the two. Possibly only up to 1 MD slot / week needed.  Training (Simon) on data acquisition required beforehand. M. E. Angoletta “PSB Finemet upgrade” MSWG 24/04/

Plans for 2015 – summary of MD requirements Parallel MDS: 3 x ½ days per week until mid September. Possibly more MDs afterwards (until December?) to answer additional questions from reviewers/management. Dedicated MD: Between ½ day and 1 day when possible in June/July. NB: Strong engagement from RF group. Sizeable amount of manpower required for development, studies and MDs support. M. E. Angoletta “PSB Finemet upgrade” MSWG 24/04/

Conclusions & outlook  Finemet (FT3L)-based HLRF: viable alternative to ferrite C02 + C04 HLRF systems for PSB.  Successful tests in 2012 highlighted weakness/desired improvements that now are removed/obtained. HLRF + LLRF installation done during LS1 allows Finemet operation close to final situation.  Finemet review in Sept ‘14 positive on project.  Aggressive MD plan for 2015: LLRF operation, HLRF tests and simulation development. Critical path as it competes with other projects for manpower.  Finemet review in Sept ‘15 + management decision by end M. E. Angoletta “PSB Finemet upgrade” MSWG 24/04/ PSB: very high priority for and strong engagement (manpower) by the RF group. We ask MSWG to support us with our MD requests.

References S. Baird, “Keeping The Present LHC Injector Complex Running for 25 Years”, Chamonix R. Garoby et al., “Upgrade Plans for the LHC Injector Complex”, IPAC2012, New Orleans, Louisiana, USA, 2012, p K. Hanke et al., ”Status and Plans for the Upgrade of the CERN PS Booster”, IPAC2015, Richmond, USA, C. Ohmori et al., “Developments of Magnetic Alloy Cores With Higher Impedance for J-PARK Upgrade”, IPAC2010, Kyoto, Japan, 2010, p M. M. Paoluzzi et al., “Beam Tests and Plans for the CERN PS Booster Wideband RF System Prototype”, IPAC2013, Shanghai, China, 2013, p M.M. Paoluzzi et al., “Studies on a Wideband, Solid-State Driven RF System for the CERN PS Booster”, IPAC2012, New Orleans, Louisiana, USA, 2012, p M. E. Angoletta et al., “A Leading-edge Hardware Family for Diagnostics Applications and Low-Level RF in CERN’s ELENA Ring”, IBIC2013, Oxford, UK, 2013, p [1] [2] [3] [4] [5] [6] [7]

References – cont’d M. M. Paoluzzi et al., “Beam Tests Using a Wide Band RF System Prototype in the CERN PS Booster”, IPAC2015, Richmond, USA, D. Quartullo et al., “Longitudinal Spac-Charge Simulations with BLONG at Injection in the CERN’s PS Booster”, talk presented at the EuCard/Xbeams Workshops on space Charge, Oxford, 24 March V. Forte et al., “Longitudinal Injection Schemes for the CERN PS Booster at 10 MeV Including Space Charge Effects”, IPAC2015, Richmond, USA, 2015, MOPH231. S. Albright, D. Quartullo et al., “RF Measurements in the PSB Ring 3 for LHC25ns beams”, BE/RF MD note under publication. [8] [9] [10] [11]