LTU/Undulator Commissioning Plans Heinz-Dieter Nuhn, SLAC / LCLS June 16, 2008. Overview Pre-Beam Checkouts LTU to Dump Commissioning (No Undulator Segments) Undulator Segments Commissioning Characterization of Spontaneous Synchrotron Radiation Characterization of SASE. - PowerPoint PPT Presentation
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OverviewPre-Beam CheckoutsLTU to Dump Commissioning (No Undulator Segments)Undulator Segments CommissioningCharacterization of Spontaneous Synchrotron RadiationCharacterization of SASE
Perform radiation surveys in BTH/FEE, etc with beam in the dump (Stan Mao, et al.)Checkout BPMs (timing, scale, sign errors, etc.)Test MPS (toroid collimators, BPMs, loss monitors, magnets, trip the beam, etc?)Checkout optics using beam oscillation data (does a betatron oscillation fit the model well everywhere? – backwards quads?)Test/checkout BYKIK and its abort dump and logic (MPS).Test/checkout new OTR screens/cameras (OTR30, OTR33, and OTRDMP).Test/checkout new wire scanners (WS31, 32, 33, 34).Test/checkout new adjustable collimators (CEDL1, CEDL3, CX31, CY32, CX35, CY36)Commission new energy and launch feedback loops.Characterize beam, etc.
Conditions for First Beam:All Undulator Magnets Rolled-OutSingle Shot Operation (low charge)
Send single electron bunch through undulatorRead and evaluate as much diagnostics as possible along undulator(such as BPMs, beam loss monitors, toroids)Identify and remove sources of beam loss – if any Iterate
Goal: Get beam through vacuum chamber with minimum losses.Reminder: Main Constraint is to Protect Undulator from Radiation Damage
Characterization of Spontaneous Radiation (May – Jun 09)
Initially at 1.5 Å to reduce damage issueStart at low chargeRepetition rate of 10 Hz or lower will be sufficientStart to characterize radiation at last undulator
Measure:total spontaneous energy / pulsespontaneous beam directiontemporal variation in spontaneous beam parametersspatial distribution around first spontaneous harmonicspontaneous radiation spectrumwavelength of first harmonicfirst harmonic wavelength spread
Characterize radiation from each individual UndulatorMeasure relative K of Undulator pair.
Limited capability Limited capability using K using K SpectrometerSpectrometer
Measure synchrotron radiation spectrum produced by two undulator segments, and scan K of one segmentK’s are matched when spectrum has the steepest slope on high energy side of 1st harmonic peak. Match segments pair-wise until all segments are measured.
Angle-Integrated Spontaneous Spectrum for 2 Undulators with Angle-Integrated Spontaneous Spectrum for 2 Undulators with KK//KK = = 0.2 to +0.2%0.2 to +0.2%
0.1% rms 0.1% rms ee energy jitter energy jitter0.003% rms 0.003% rms ee energy energy meas. resolutionmeas. resolution2% rms charge jitter2% rms charge jitter0.5% charge meas. res.0.5% charge meas. res.0.50.5 rms angle jitter rms angle jitter101055 photons/pulse/0.01% photons/pulse/0.01%100 photon noise100 photon noise100 beam pulses with 100 beam pulses with natural energy jitter onlynatural energy jitter only
Initially at 15 Å to maximize SASE gainStart with reduced number of undulatorsRedo BBA after change of undulator configuration
Verify that electron beam meets requirementsFind SASE signal using Direct ImagerUse Laser-Heater modulation to control gain(7 Hz Lock-In Detection) if necessaryRepetition rate of 30 Hz (to support Lock-In Detection)Optimize gain (through electron beam quality and BBA)Measure gain length etc…
Undulator Segments can be rolled-out by remote control. Roll-out will start at the last Segment. Rolled-out Segments will not effect radiation produced by earlier segments.