1. 3 MeV test stand measurement plans A. Lombardi for the LINAC4 team 10/01/2013BCC 41 - 3MeV test stand measurements1

2. Scope Validate Source and LEBT design RFQ design Chopper Ultimate goal is to demonstrate 70 mA H- 400 µs 1 Hz 3 MeV 0.4 mm mrad 0.15 deg KeV Chopped and matched to the DTL Source 45 keV RFQ 3 MeV Chopper Diagnostic line

3. LINAC end-to-end Location and causes of e growth and losses: LEBT solenoids (divergent beam from the source). 45 keV MEBT transport (abrupt change of phase advance). 3 MeV BOTH ARE UNAVOIDABLE but they must be controlled

4. Emittance 0-3 MeV Symmetry x,y in LEBT, if source is symmetric Losses in the RFQ, emittance decreases Losses and emittance increase when matching to the DTL

5. bench 10/01/2013BCC 41 - 3MeV test stand measurements5 Spectrometer (0.2 %) Slit and Grid Emittance ToF (calibration) Bunch Shape Monitor Halo Monitor (chopping eff.) Transformers Feshenko EDMS – 1004908 G. Bellodi

6. Measurement plan – 1/2 10/01/2013BCC 41 - 3MeV test stand measurements6 Stage 1 – after the RFQ 9 parameters : 2 solenoids, RFQ amplitude, 2 quads, 2 steerers ScanMinimum beam 1) RFQ TransmissionSolenoids, RF powerInitially I =20 mA (min) Emi= 0.5 (max) Needs I=70 mA Emi = 0.25 to fully validate. 2) RFQ emittanceSolenoids, RF power 3) RFQ energy spread/longitudinal emitt Solenoids, RF power NEED TO ACHIEVE TRANSMISSION THROUGH THE RFQ OF 80% TO GO TO THE NEXT STAGE (NOMINAL TRANSMISSION IS 92%)

7. Measurement plan – 2/2 10/01/2013BCC 41 - 3MeV test stand measurements7 Stage 2 – after the chopper 30 parameters : stage 1 parameters + 11 quads, 3 RF ampli, 3 RF phases, chopper voltage, 2 steerers ScanMinimum beam At RFQ input 1) TransmissionAll parametersInitially I =50 mA (min) Emi= 0.4 (max) Needs I=70 mA Emi = 0.25 to fully validate. 2) CHOPPINGPencil beam All quads 3) Transverse emittance 4) Longitudinal planeBuncher settings FULL CHARACTERISATION IS NOT POSSIBLE, BUT GIVE PRIORITY TO THE MORES CRITICAL ITEMS

8. Pencil beam All elements on Chooper on (top) Chopper off (bottom) With this we validate : 1)Chopper voltage 2)Optics we do not validate : 1)Space charge 2)Rise/fall time MOST IMPORTANT MEAS BEAM AT THE ws JUST BEFORE THE INLINE DUMP

9. Measurement 2011 – p from DESY OP DAY - 26th January 2012 Archamps9 RFQ acceptance vs. Measured emittanceMeasured after source vs. Measured at the RFQ input plane and backtracked to the source

10. Protons Already discussed – EDMS 1096658 Measurement with Desy source in proton mode (2011) gave an excellent insight into LEBT dynamics and solenoid modelling To be done before protons are usable : optimise to reach a min of 50-60 mA after the first solenoid, measure emittance vs. solenoid settings (5-10) and back-trace to source input : create a beam for simulating/optimising the whole test stand. 10/01/2013BCC 41 - 3MeV test stand measurements10

11. Sharing the test stand- proposal (change over takes ½ day to 1 day) Run in proton mode until the emittance metre has to be dismantled Source development till RFQ ready for beam Share 2:1 between 3 MeV measurements and source development, over 3 weeks period or as best convenient. DO NOT FORGET COMMISSIONING TIME FOR DIAGNOSTICS 10/01/2013BCC 41 - 3MeV test stand measurements11

12. Proposal - 3 MeV beam commissioning must be done in 2 sessions/day on the basis 5 days/week. E.g. 7:00- 14:00 and 14-21 We (BD team) are 3 staff + 3 visitors Daily brief meeting with the people on the field + 1 by-weekly meeting in the control room to take decisions – CALLED BY GB Need experts available as much as possible (in 2011 we “took it easy” but it took 6 months to measure the LEBT!) 10/01/2013BCC 41 - 3MeV test stand measurements12

13. Something has to give… Laser stripping measurements ( make sure that BI is made aware) Halo measurements under different matching Matching to the DTL Buncher optimisation Pencil beam scans Calibration of TOF vs. spectrometre…….. And many more 10/01/2013BCC 41 - 3MeV test stand measurements13 The time presently allocated for commissioning in the tunnel is not sufficient-need 6 months We should repeat the measurements after the RFQ in the tunnel