P. Urschütz - CTF3 Collaboration Meeting 2007 CTF3 commissioning & operation in 2006 P. Urschütz for the CTF3 operations team  Commissioning of the Delay Loop  Commissioning of the Transfer Line 1 & injection into the Combiner Ring  Long pulse, fully beam loaded Linac operation

P. Urschütz - CTF3 Collaboration Meeting 2007 Missing instrumentation: only 6 Beam Pickups installed out of 17 (one in CT line, 5 in DL) Beam limited to low current (1 A), short pulse (300 ns) because of radiation protection reasons Only one SHB cavity available out of three Relaxed optics in Delay Loop (non-isochronous) (2 combined function magnets are wrongly installed… new optics for DL, 3 DL quadrupole families had calibration error) Commissioning status at the end of 2005… … and plans for 2006 Additional Instrumentation: more Pickups (+ 2 BPIs in DL) Re-combination with nominal beam current (3.5 A), long beam pulse (1400 ns) Sub harmonic bunching with all 3 SHB cavities Isochronous optics Measurement of satellite bunch population, time of phase switch in SHBs Dispersion measurements in DL, bunch length measurements,… Delay Loop commissioning

P. Urschütz - CTF3 Collaboration Meeting 2007 How does the bunch frequency multiplication work? CTF3 Injector with 3 SHB cavities (1.5 GHz) Beam combination with transverse RF deflector Phase coding and bunch frequency multiplication in delay loop “phase coding” SHB gun buncher 2 accelerating structures

P. Urschütz - CTF3 Collaboration Meeting 2007 Commissioning of the Delay Loop – SHB system Key parameters for the SHB system: 1) time for phase switch < 10 ns ( GHz periods) 2) satellite bunch population < 7 % (particles captured in 3 GHz RF buckets) phase switch: satellite bunch population: Phase switch is done within eight 1.5 GHz periods (<6 ns). Satellite bunch population was estimated to ~8 %. main bunch satellite bunch

P. Urschütz - CTF3 Collaboration Meeting 2007 Delay Loop, path length tuning I DL wiggler has path length tuning range of ~ 9 mm RF phase monitor* after the DL to measure phase error in the RF bunch combination. (*Uppsala University - talk this afternoon by A. Ferrari) 9 GHz e-e- 7.5 GHz 12 GHz 10.5 GHz RF antenna RF Bandpass filter Diodes measure harmonics of 1.5 GHz

P. Urschütz - CTF3 Collaboration Meeting 2007 Wiggler off Wiggler on Bunch from the linac Bunches from the DL Bunches from the DL later by 12ps (3.6mm) OTR light downstream the Delay Loop Better RF combination 7.5 & 10.5GHz 9 & 12 GHz Delay Loop, path length tuning II Thanks to our BDI guys T.Lefevre, C.Welsch 333 ps

P. Urschütz - CTF3 Collaboration Meeting 2007 Dispersion measurements I o measure reference trajectory at nominal magnet settings o scale magnets by small amount (~1%) o CT Line o Delay Loop o observe difference trajectory o E = 101 MeV Linac + CT Line Delay Loop magnetic chicane

P. Urschütz - CTF3 Collaboration Meeting 2007 Dispersion measurements II o In general good agreement between model and measurement o worse in the second half of DL; wiggler or combined function magnet mismatch ? o overall, data for lower currents fits better. o We do not have many BPIs!

P. Urschütz - CTF3 Collaboration Meeting 2007 Bunch Length measurements – streak camera MTV0361  = 8.9ps (2.7 mm) “Natural” chicane - R56 = 0.45 MTV0550  = 4.5ps (1.4 mm) “Nominal” chicane - R56 = bunch length <1.3 mm in the Linac (obtained with cleaning chicane after the injector) head-to –tail energy correlation is introduced in the accelerator (off crest acceleration & short range wake fields) magnetic chicane to increase the bunch length before the Delay Loop (up to 2.5 mm) to minimise CSR effects. measured bunch lengths are very reasonable and change of R56 clearly visible. head-to–tail energy correlation after the Linac was not the main focus so far (on-crest acceleration). good agreement to simulations with reasonable initial energy correlation.

P. Urschütz - CTF3 Collaboration Meeting Beam recombination in the Delay Loop (factor 2) Beam recombination NOMINAL BEAM PARAMETERS ? Beam current (7 A after DL) 3.3 A max after chicane -  6 A after combination (satellites) Energy (150 MeV) ~ 100 MeV – still miss MKS 15 – can gain something from others Emittance (100 π mm mrad) now consistently below nominal (  mm mrad) Pulse length (1.4 µs) “just” nominal (1.4  s after chicane, 5  140 ns pulses after DL) Bunch length (up to 2.5 mm) 1.4 – 2.7 mm (nominal and natural R56 of chicane), head-to-tail energy correlation of the bunch after the Linac?

P. Urschütz - CTF3 Collaboration Meeting 2007 Commissioning of TL1 & CRM Delay Loop - commissioned with beam Linac - commissioned with beam CRM commissioning – end of 2006 TL1 DL CRM Bypassing the Delay Loop low gun repetition rate (1 Hz) No sub harmonic bunchers - 3 GHz beam beam current: 3.5 A short pulse length: ~ 200 ns one additional Klystron (MKS15), higher energy: ~ 125 MeV Just 3 weeks of commissioning – effective 80 hours!

P. Urschütz - CTF3 Collaboration Meeting 2007 Transmission in TL1 & CRM o 3.2A at the end of CT line. o About 3A after injection into CR (94%). o Magnetic and RF injection (with same transmission). o Nominal, isochronous optics in TL1

P. Urschütz - CTF3 Collaboration Meeting 2007 Transmission & trajectory in TL1 & CRM TL 1 CRM CT Transmission and trajectories from end of CT line to CRM Beam image at the end of CRM.

P. Urschütz - CTF3 Collaboration Meeting 2007 Dispersion measurements in TL1 & CRM TL 1 CRM Dispersion measurement by magnet scaling within +/- 1% (QFF0690 optimized for zero disp) Nominal, isochronous optics in TL1 and we are asking for zero dispersion in CRM. But in operation: non zero dispersion measured in CRM… we always had to change one quadrupole to compensate. Good agreement for the first part of TL1, discrepancy afterwards. Drift of the machine, Energy was changing QFF0690 o quadrupole: wrong magnetic field (short in one of the coils). o model: Is it correct? Kick studies with steerers to better understand this discrepancy (to be analysed).

P. Urschütz - CTF3 Collaboration Meeting 2007 Matching of TL1 & CRM o Quad scan at the end of CT line. o Matching of TL1 and CRM. o Quad scan at the end of CRM. Emittances (ε n,rms ) in x and y plane between 40 – 80 π mm mrad (nominal 100 π mm mrad) at the end of CT line and CRM! Twiss parameters from measurement and MAD prediction disagree (same problem than for dispersion). What else did we do? o Streak camera studies … talk this afternoon (Carsten Welsch) o Bunch length monitor studies (RF pick up) … talk this afternoon (Mayda Velasco, Anne Dabrowski)

P. Urschütz - CTF3 Collaboration Meeting 2007 Most of RF power to the beam RF in No RF to load “short” structure - low Ohmic losses High beam current Fully beam loading operation in CTF3 SiC load HOM damping slot CTF3 Drive Beam Acc. Structures (3 GHz) – SICA (Slotted Iris – Constant Aperture): 32 cells 1.2 m long 2π/3 mode 6.5 MV/m av. acc. gradient for 3.5 A beam current HOM damping slots theoretical RF-to-beam efficiency: 96%

P. Urschütz - CTF3 Collaboration Meeting 2007 Full beam loading operation in CTF3 – Demonstration for CLIC operation CLIC: no RF pulse compression length of the drive beam pulse: 100 µs Demonstration at CTF3: MKS03 MKS07 MKS06 MKS05 Spectrometer 10 Spectrometer 4 Setup: no RF pulse compression for this experiment (with exception of MKS03) 1.5 µs long pulses Adjust RF power and phase and beam current, that fully loaded condition is fulfilled RF pulse at structure output RF pulse at structure input analog signal 1.5 µs beam pulse

P. Urschütz - CTF3 Collaboration Meeting 2007 Full beam loading operation in CTF3 – Demonstration for CLIC operation measured RF-to-beam efficiency: 95.3 % Theory: 96% (~4 % ohmic losses) Idea: Delay always one klystron pulse after the beam pulse and measure relative energy in spectrometer 10 and compare with calculations. MKS05MKS06MKS07 in outin total energy lower energy from calculations (beam current) o “missing” acceleration (energy gain per structure) o deceleration due to direct beam loading compare to theoretical energy gain (input power, beam current) An exact knowledge of the structure input power, the beam current and the energy gain is essential.

P. Urschütz - CTF3 Collaboration Meeting 2007 Conclusions Delay Loop:  Fully commissioned with “quasi” nominal parameters (6A re-combined beam current, 1.4 µs pulse length, ε n,rms < 100 π mm mrad, tunable bunch length ~ 2mm)  3 SHB operational, phase switch time < 6 ns, satellite bunches < 8% TL1 & CRM:  very good transmission until the beam dump  magnetic and RF injection into CRM  small emittances  made important studies with several BDI equipment  but, a better understanding of dispersion and optics has to be obtained Fully beam loaded operation:  very successful demonstration of the long pulse fully loaded operation with an measured RF-to–beam efficiency of 95.3%. within short time: Thanks to everybody participating in the commissioning and operation of CTF3 during the 2006 run!