Bruno Muratori (for the EMMA team) STFC, Daresbury Laboratory EMMA commissioning 02/09/08

Overview What is commissioning ? –Preparing machine for beam set-up DAQ & controls & hardware set-up diagnostic devices required –Getting beam into the machine & where you want it –Making sure all desired properties are achieved for the bunch (full characterisation etc.) for the machine (e.g. dispersion-free sections) –Set-up machine for particular experiments –Need as many simulations of the machine as possible !

I. Gun commissioning - complete (December 2007) II. First energy recovery - will start now (September 2008) ! - all procedures are ready (in Wiki) - online modelling (Mathematica based), being currently developed - get the energy recovery without FEL first III. Machine tuning - fine beam tuning - phase space manipulation to achieve minimal bunch length - full beam characterisation - EO bunch length measurements ALICE commissioning (1)

IV. Energy recovery with FEL - first light from FEL - energy recovery of FEL disrupted beam - commissioning complete V. ALICE exploitation - CBS experiments - tomography with space charge (in EMMA injection line) - other experiments (e.g. linac transfer matrices measurement) - preparations for EMMA commissioning ALICE commissioning (2)

ALICE schematic Need similar schematic for EMMA injection line, ring and extraction line (shall be enormously more detailed … !)

Injection Line Commissioning (1) I Prepare ALICE as Injector for EMMA –Set required beam energy (e.g. 10 MeV) –Beam characterisation Bunch length / Charge / Emittance / Energy spread / other ? –Hardware commissioning –Controls & online model commissioning These should be as comprehensive as possible (within reason) –DAS commissioning

Injection Line Commissioning (2) Set initial charge at 1 pC II Thread beam through injector line –Cancel dispersion in diagnostic straight –Steering: use steerers & kickers to get beam to given point & with right angle depending on energy and required septum settings –Beam characterisation (as much as possible – as always !) –Comparison with models wherever possible

Injection Line Commissioning (3) III EMMA ½ turn → extraction –Threading beam without acceleration –Threading beam with acceleration –Characterisation of beam in both cases (extraction / diagnostic line) IV EMMA 1 ½ turn → extraction –Threading beam without acceleration –Threading beam with acceleration –Characterisation of beam in both cases (extraction / diagnostic line)

Injection Line Commissioning (4) V EMMA 10 turn → extraction –Same as before but In one go ? Step by step ? (i.e. one turn at a time) –Characterisation of beam in all cases Set nominal charge (q = 16 or 32 pC) VI Repeat all of the above VII EMMA exploitation –Establish Orbit –Tune measurements –Aperture survey

ALICE EMMA ALICE quadrupoles SRS quadrupoles New quadrupoles Faraday Cup Screen last dispersive section Diagnostics: injection line

Diagnostics – injection line (1) OTR Screen in ALICE before extraction dipole entrance of every dipole in injection line Straight ahead Faraday cup to measure charge & energy spread OTR screen in dogleg for bunch length & energy measurement Tomography section: 60 degrees phase advance per screen with three screens for projected transverse emittance measurements

Diagnostics – injection line (2) Last dispersive section: –OTR screen & vertical slit in middle of first section together with –OTR screen in final section for energy and energy spread measurements –Vertical steerers for position & angle before ring (to be used with kickers for steering) –BPM at entrance of EMMA ring for position before entering

Online Modelling (1) Build on ALICE experience –Gun commissioning Script to run ASTRA for comparisons / predictions –Injection line Run GPT for space charge calculations in ALICE Script to run ELEGANT / other for remainder of ALICE –ALICE ring Script to run ELEGANT / GENESIS / other codes for lasing etc.

Online Modelling (2) Create model of ALICE to EMMA injector line in GPT –Run this model both on & off line for comparisons / predictions Create S2E model for all of EMMA in GPT –Run with field maps & misalignments for comparisons / predictions –Run all the way to spectrometer & dump in the EMMA extraction line Compare this with ZGOUBI models & FFEMMAG models wherever possible

Online Modelling (3) Ring optics – what things may look like courtesy S. Machida

Online Modelling (4) Injection orbit and optics - what things may look like Set septum and kicker strength See orbit and optics of incoming beam courtesy S. Machida

Injection Septum 65° Kicker Cavities x 19 Extraction Septum 70° Kicker Screen Wire Scanner Wall Current Monitor Wire Scanner Screen BPM x 82 D Quadrupole x 42 F Quadrupole x Vertical Correctors IOT Racks (3) Waveguide distribution EMMA Ring Kicker Power Supplies Septum Power Supply Septum Power Supply Kicker Power Supplies

Establishing the orbit (1) Look at Beam Position Monitor (BPM) one by one from the injection point (not symmetric → not straightforward) Adjust initial beam position (x,x’,y,y’) as well as Quad current and position BPM

Establishing the orbit (2) Double focusing lattice (QF and QD) Bend fields are created by shifting quadrupoles QF QD Linear slide 4 knobs –QF and QD strength –QF and QD position (horizontally) 4 parameters to fit –Q x and Q y –TOF shape and offset

ERLP EMMA SRS quadrupoles New quadrupoles TD Cavity spectrometer dipole Diagnostics: extraction line

Diagnostic line deflecting cavitytomographyEO spectrometer

NEW DIAGNOSTICS BEAMLINE LAYOUT Spectrometer dipole entrance Screen Faraday Cup E-O Monitor Screen x 3 Tomography Section Wall Current Monitor BPM & Valve SRS Quadrupoles x 6 New Quadrupoles x 4 ALICE New Dipoles (43°) & BPMs at dipole entrance Current measurementLongitudinal profile Position measurement New Quadrupoles x 4 Screen & Vert. Slit Emittance measurement Extracted momentum Location for Transverse Deflecting Cavity (NOT IN BUDGET) Screen

Measurements in diagnostic line Energy –First dipole & spectrometer at end with OTRs Emittance –Quadrupole scans & tomography 60° phase advance / screen –Equivalent set-up in injection line for comparisons Bunch length –EO monitor downstream of tomography –No profile information

Measurements with TDC Slice emittance & transverse profiles given by –knowledge of R 12 from TDC to screen –horizontal dimension on screen gives slice emittance –vertical dimension gives bunch length Slice energy spread given by –streaked beam and spectrometer

Experiments on EMMA Cross different large resonances Measurement of time of flight –Change frequency until no synchrotron oscillations –Frequency then translates into TOF –Hence find minimum of TOF Relationship of TOF to lattice parameters / tune –Tune vs. energy Study variation of all parameters to lattice properties Interpretation of BPM readings –Not all identical & only symmetry every other cell –Important to model all BPM readings → GPT / other

Aperture survey Phase space at injection Scan aperture in phase space with a pencil beam See S. Tzenov’s talk for more details When is normalized acceptance is 3 mm rad ? Explore acceptance at all energies Should also be modelled with FFEMMAG, GPT & others To be done at all energies from 10 to 20 MeV x’ x pencil beam

Conclusions / Discussion Commissioning for EMMA will be a lengthy procedure ! As many models as possible are required for all aspects of the machine –At all energies –For all lattices These may be far from perfect but should give insight into the trend or pattern of beam behaviour e.g. ALICE solenoid scan Online models should also be done where possible & necessary