Overview Step by step procedure to validate the model (slide 1 and 2) Procedure for the Ql / beam loading study (slide 3 and 4)

Simulator validation procedure – STEP 1 LOW GRADIENT, BEAM OFF Initial conditions – proceed at low gradient (~10-15 MV/m) – beam off – FB off, AFF off, standard step FF table – no dynamic piezo compensation Check the power hybrid settings (ACC6/ACC7) – cryomodule forward power read outs (ACC6 and ACC7) ? Check that all cavities are set to Q L =3e6 – read backs from DOOCS – cross check with DAQ data – adjust if necessary Check that all cavities are on resonance – read backs from DOOCS – cross check with DAQ data – adjust if necessary Compare cavity gradients – at end of fill time – “calibrate” P K distribution on the model Compare cavity phases – check phase waveforms – “calibrate” simulator by adjusting phase offsets Compare cavity tilts – if any, understand where they come from (cavity detuning ? LFD ? coupler directivity ?)

Simulator validation procedure – STEP 2 HIGH GRADIENT, BEAM OFF Increase gradient – reach nominal operating gradient – define administrative quench limits – turn FB on – turn AFF on – turn piezo dynamic compensation on (if available) For each cavity, check – Pfwd (DAQ waveforms and simulator) – Pref (DAQ waveforms and simulator) – Vcav (DAQ waveforms and simulator) amplitude and phase – Q L (DAQ waveforms and simulator) – Detuning (DAQ waveforms and simulator) Possible model limitations – klystron non-linearities – uncompensated Lorentz force detuning – adjacent cavities coupling effects – limited directivity at couplers (Pfwd, Pref) – thermal effect at circulators (introduces hysteresis effect, non-linearities) HIGH GRADIENT, BEAM ON Turn beam ON – low beam (1mA ?) – Quantify beam loading FF ratio needs adjustment ? Amplitude of beam loading compensation Beam induced detuning – can we run with beam but without FB and AFF ? – can we run with beam but without piezo compensation ? Compare cavity tilts – logged in the DAQ ? – compare with simulator (beam ON / beam OFF) – can we change the beam length ? (100, 200, 300 usec ?) – can we scan the beam time over the RF flat top ? (over the whole 800 usec ?) – compare with energy profile  vector sum calibration Proceed with Ql studies

Procedure for Q L / beam loading studies Initial conditions – Start beam off – all cavities set to Q L = 3e6, zero detuning, nominal gradient – all cavity gradients flat Turn beam ON – 1 mA, (2mA, 3mA) – 200 usec Check gradient tilts – do they match predicted tilts ? – within administrative quench limits ? Adjust ratio for flat Vsum – ratio adjustments as expected ? Check gradient tilts – do they match predicted tilts ? – within administrative quench limits ? Check if cavities are detuned – DAQ data cross check – record individual detuning Proceed with Q L adjustments – one cavity at a time – best if performed open loop (is it possible, is it safe ?) – for each cavity, record: optimal experimental Q L resulting detuning Q L adjustment time (for DAQ offline analysis) – compare with simulator optimal Q L Check Q L of adjacent cavities – tune cav.1, record Q L 1 – tune cav.2, record Q L 2 – re-check Q L 1 – etc… Retune cavities – static detuning (piezo DC offset if available, slow tuner otherwise) – compensate for LFD with piezo (or operate at lower gradient to avoid them) – log all retuning adjustments – re-check QL’s Verify gradient flatness – after all QL’s have been adjusted, FB, AFF on ? – verify that all cavity gradients are flat – verify that the vector sum is flat – verify that the beam profile is flat Turn beam OFF – no Q L adjustment – record cavity tilts  compare with simulation – do we exceed administrative quench limits This procedure assumes the possibility to run beam open loop, with no AFF, no FB Beam compensation should be included in the model

Procedure for Q L / beam loading studies : adjusting Q L without beam If we can’t run beam without FB and without AFF – Turn beam OFF – No FB, no AFF – Set the machine to predicted optimal Q L follow same steps as described above – Measure tilts compare with simulation within administrative limits? – Measure detuning – Compensate for static detuning – Check Q L after retuning adjust if needed – FB on – Turn beam ON – AFF on, beam compensation on – Measure tilts verify gradient flatness