1. LTU & Undulator Commissioning Plans Heinz-Dieter Nuhn, SLAC / LCLS May 14, 2008
Overview
Pre-Beam Checkouts
LTU to Dump Commissioning (No Undulator Segments)
Undulator Segments Commissioning
Characterization of Spontaneous Synchrotron Radiation
Characterization of SASE
May 14, 2008 1

2. LCLS Installation and Commissioning Time-Line
First Light
in FEE
First Light
in FEH
LTU/Und/Dump Install
PPS Cert. LTU/Dump
FEE/NEH Install
Undulator Seg. Install
X-Rays in NEH
FEH Hutch BO
CD-4 (7/31/2010)
PEP-II run ends
FEH Install
now J F M A S D O N
Down
PPS
Linac/BC2 Commissioning
Re-commission Inj/BC2 to SL2
LTU/Und
Comm.
NEH Operations/ Commissioning
FEE
Comm.
April 18, 2008
May 14, 2008 2

3. Beam-Based Commissioning
2008
2009
Beam-Based Commissioning A B C
A: LTU – Dump
B: Undulator Segments
C: Spontaneous X-Rays
D: SASE
e--Beam D
X-Ray
May 14, 2008 3

4. LTU/Undulator e--Beam Commissioning Blocks
Installation and Conventional Alignment (=>Nov 08)
All beamline components except Undulator Segments
Pre-Beam Checkouts (Checklists will be prepared) (Nov-Dec 08)
LTU Section
Magnet Polarities / Motion (OTR, Collimators, Wire-scanners) / etc.
Undulator Section
Magnet Polarities / Motion (Girder, BFW, Slide) / ADS Calibration / etc.
Pre-Undulator Commissioning with Beam (Jan 09 – Mar 09)
Beam-Based Alignment / Motion Control / Beam Containment / etc.
Beam Dump Section
Installation of Undulator Segments (Mar 09)
Undulator Commissioning with Beam (Mar 09 – Apr 09)
Beam Based Alignment / Undulator Slide Functions / Beam Stability A B
May 14, 2008 4

5. LTU-to-Dump Pre-Beam Checkouts (Nov-Dec 08)
Undulator Hall HVAC System checkout (before Girder installation)
ADS (WPM & HLS) commissioning
ADS Control System checkout
EPICS Control System Checkout
Network Configuration of IOC's
Timing System
Communication with ADS Checkout
Verification of individual Device Operation
Magnet Power Supplies and Interlocks
Magnet Polarity Checkout
Dipoles
Quadrupoles
Correctors (where power supplies available)
BPM Cable Checkout
Motion Checkouts
Movable Collimator motion
Wire Scanner motion & calibration
Beam Finder Wire In/Out motion (BFW01 – BFW33)
Girder Motion Control checkout (33 Girders using external pos. sensors)
CAM Mover motion checkout
Transverse slide motion checkout
Compound motion checkout (Smooth beamline motion, System re-pointing)
May 14, 2008 5

6. LTU Commissioning with Beam (Jan-Mar 09)
Perform radiation surveys in 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.
May 14, 2008 6

7. Undulator Beamline Commissioning to Main Dump with Beam but without Undulator Segments (Jan-Mar 08)
Commission Radiation Monitors
Get Beam through Undulator vacuum pipe with minimum losses.
Calibrate RF Cavity BPMs
Including sign determination.
Commission Girder Motion with Beam
Verify and calibrate steering effect of quadrupole motion
Calibrate motion parameters (gain, pivot points etc.) Check BPM offset tracking
Commission RF Cavity BPMs
Check charge dependent response over entire charge range
Use Girder Motion to calibrate position vs. readings
Check and correct optics matching over entire operational energy range
Commission Beam Based Alignment (BBA)
Develop saved configurations for three different energies.
Commission BBA GUIs and BBA procedure.
Commission Beam Finder Wires
Calibrate PMT signals.
Commission BFW GUIs (Alignment and scanning capabilities)
Commission ADS-based girder position stabilization feedback systems.
Commission Tune-Up Dump in preparation for commissioning with Undulator Segments
May 14, 2008 7

8. Install Undulator Segments (Mar 09)
Mount Undulator Segments onto girders Segments will be stored in Undulator Hall before installation
System is designed to be Self-Aligning
Re-check girder motion control
Expect to install 3 Segments / day
May 14, 2008 8

9. First Beam Through Undulator Segments (Mar 09)
Conditions for First Beam:
All Undulator Magnets Rolled-Out
Single Shot Operation (low charge)
Send single electron bunch through undulator
Read 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
May 14, 2008 9

10. First Undulator Segments Commissioning (Mar – Apr 09)
Undulator Segments still in Roll-Out position
Run BBA
Roll-In Individual Undulator Segments
Transport beam through individual Undulator Segments Start at slot #33 (last Undulator Segment)
Check and correct trajectory change.
Run BBA with Undulator Segments inserted.
Check Segment alignment with BFWs B
May 14, 2008 10

11. Commissioning of X-Ray Diagnostics (May – Jun 09)
Direct Imager
Slit
Solid Attenuator
Gas Attenuator
Gas Detector
Beam-Based K Measurement Components
Minimum Requirement
X-Ray Diagnostics is located after last Undulator Segment in Front-End Enclosure (FEE)
See presentations by Tompkins and Bionta
May 14, 2008 11

12. X Ray Diagnostics (FEE)
5 mm diameter collimators
Gas Detector
Soft X-Ray Offset mirror system
Hard x-ray Monochromator
(K Spectrometer)
Direct Imager
Solid
Attenuator
NFOV
Slit
Total
Energy
Thermal Detector
Hard X-Ray Offset mirror system e-
WFOV
Gas Detector
Start of Experimental
Hutches
Muon Shield
Gas
Attenuator
May 14, 2008
See presentations by Tompkins and Bionta 12

13. Characterization of Spontaneous Radiation (May – Jun 09)
Initially at 1.5 Å to reduce damage issue
Start at low charge
Repetition rate of 10 Hz or lower will be sufficient
Start to characterize radiation at last undulator Measure:
total spontaneous energy / pulse
spontaneous beam direction
temporal variation in spontaneous beam parameters
spatial distribution around first spontaneous harmonic
spontaneous radiation spectrum
wavelength of first harmonic
first harmonic wavelength spread
Characterize radiation from each individual Undulator
Measure relative K of Undulator pair. C
Limited capability using K Spectrometer
May 14, 2008 13

14. K Measurement: 2-Segment Scheme
Measure synchrotron radiation spectrum produced by two undulator segments, and scan K of one segment
K’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. C
undulator segments (33 total)
segments under test
May 14, 2008 14

15. Dj = 0 Dx = 3 mm DK/K = +0.2% ~106 photons/nC/0.01%BW DK/K = 0%
Angle-Integrated Spontaneous Spectrum for 2 Undulators with DK/K = -0.2 to +0.2% C
Dj = 0
Dx = 3 mm
DK/K = +0.2%
0.1% rms e- energy jitter
0.003% rms e- energy meas. resolution
2% rms charge jitter
0.5% charge meas. res.
0.5s rms angle jitter
105 photons/pulse/0.01%
100 photon noise
100 beam pulses with natural energy jitter only
DK/K = 0%
~106 photons/nC/0.01%BW
DK/K = -0.2%
May 14, 2008 15
Simulations P. Emma

16. Characterization of SASE (Jul – Aug 09)D
Initially at 15 Å to maximize SASE gain
Start with reduced number of undulators Redo BBA after change of undulator configuration
Verify that electron beam meets requirements
Use Laser-Heater modulation to control gain (7 Hz Lock-In Detection) if necessary
Repetition rate of 30 Hz (to support Lock-In Detection)
Find SASE signal using Direct Imager
Optimize gain (through electron beam quality and BBA)
Measure gain length etc…
May 14, 2008 16

17. FEL Measurements D Measurements along undulator
Intensity (LG, Saturation)
Measurements after undulator
Photon wavelength
Photon wavelength spread
Pulse intensity
Pulse duration
Pulse centroid and direction
Spatial distribution
Jitter
Saturation
Exponential Gain Regime
Undulator Regime
1 % of X-Ray Pulse
Electron Bunch Micro-Bunching
May 14, 2008 17

18. SASE Characterization with FEE Diagnostics
X-ray beam diagnostics located in FEE, down stream of last Undulator Segment
Obtain necessary z-dependent information through SASE gain shut-off at selectable points along undulator line by
Introduction of trajectory distortion or
Roll-out of individual undulator segments
May 14, 2008 18

19. Measurement of SASE Gain Length with Trajectory Distortion
Quadrupole Displacement at Selectable Point along Undulator
GENESIS Simulations by Z. Huang
May 14, 2008 19

20. Measurement of SASE Gain Length Using RolloutD
Undulator Segments can be rolled-out by remote control. Roll-out will start at the last Segment. Roll-out Segments will not effect radiation produced by earlier segments.
May 14, 2008 20

21. Plans for LTU/Undulator commissioning have been worked out and include
Summary
Plans for LTU/Undulator commissioning have been worked out and include
Detailed pre-beam checkout
LTU-Main Dump commissioning without Undulator Segments installed.
Installation of Undulator Segments.
Undulator Segment Commissioning
Characterization of Spontaneous Radiation will be combined with commissioning of X-Ray diagnostics suite in FEE
Beam based K-measurement method included.
Characterization of SASE will start at 15 Å
Gain length measurements will use FEE x-ray diagnostics combined with z-dependent SASE gain cut-off A B C D
May 14, 2008 21

22. End of Presentation
May 14, 2008 22

23. Application Software Development
LTU Emittance Measurement (Loos – extension of existing GUI)
Undulator Steering and re-Pointing (Nuhn)
Beta-Matching into the Undulator – with variable mean beta (Limborg)
Beam-Based Alignment of the FEL Undulator (Loos)
Beam-Finder Wire Application – Centering & Emittance (Loos/Nuhn)
K-Measurement Application (Emma/Nuhn)
There will probably be more …
May 14, 2008 23

24. Undulator Segment and TLD Replacement Program
2009
2010
May 14, 2008 24