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
June 16, 2008
LTU/Undulator Commissioning Plans
1
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
Related Presentations
Paul Emma, Commissioning Results and Plans
H. Tompkins, FEE/FEL Commissioning Overview
Richard Bionta, FEE Diagnostics and Commissioning
June 16, 2008
LTU/Undulator Commissioning Plans
2
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
First Light
in FEH
CD-4 (7/31/2010)
X-Rays in NEH
FEH Hutch BO
FEH Install
First Light
in FEE
Undulator Seg. Install
PPS Cert. LTU/Dump
FEE/NEH Install
LTU/Und/Dump Install
now
PEP-II run ends
LCLS Installation and Commissioning Time-Line
PPS
J F M AM J J A S ON D J F MAM
AM J J A S ON D J F M A M J J
Down
2008
2009
2010
Linac/BC2
Commissioning
Re-commission
Inj/BC2 to SL2
June 16, 2008
LTU/Undulator Commissioning Plans
LTU/Und
NEH Operations/
Comm.
FEE Commissioning
Comm.
3
May 2, 2008
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
2008
2009
Beam-Based Commissioning
A
B
C
A: LTU – Dump
B: Undulator Segments
C: Spontaneous X-Rays
D: SASE
June 16, 2008
LTU/Undulator Commissioning Plans
e--Beam
D
X-Ray
4
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
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) (Oct-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) A
LTU Section
Undulator Section (w/o Undulator Segments)
Motion Control / Beam Containment / Beam-Based Alignment / etc.
Beam Dump Section
Installation of Undulator Segments (Mar 09)
Undulator Commissioning with Beam (Mar 09 – Apr 09) B
Beam Based Alignment / Undulator Slide Functions / Beam Stability
June 16, 2008
LTU/Undulator Commissioning Plans
5
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
LTU-to-Dump Pre-Beam Checkouts (Oct-Dec 08)
Undulator Hall HVAC System checkout (before Girder installation)
ADS (WPM & HLS) Control System checkout
ADS commissioning
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)
June 16, 2008
LTU/Undulator Commissioning Plans
6
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
LTU Commissioning with Beam (Jan-Mar 09)
A
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.
June 16, 2008
LTU/Undulator Commissioning Plans
7
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
Undulator Beamline Commissioning to Main Dump with
Beam but without Undulator Segments (Jan-Mar 08) A
Commission Radiation Monitors
Get Beam through Undulator vacuum pipe with minimum losses.
Checkout BPMs (timing, scale, sign errors, etc.)
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
June 16, 2008
LTU/Undulator Commissioning Plans
8
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
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 slide motion clearance
Expect to install 3 Segments / day
June 16, 2008
LTU/Undulator Commissioning Plans
9
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
First Beam Through Undulator Segments (Mar 09)
B
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
June 16, 2008
LTU/Undulator Commissioning Plans
10
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
First Undulator Segments Commissioning (Mar – Apr 09)
Undulator Segments still in Roll-Out position
B
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
June 16, 2008
LTU/Undulator Commissioning Plans
11
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
Commissioning of X-Ray Diagnostics (May – Jun 09)
Minimum Requirement
Direct Imager
Slit
X-Ray Diagnostics is located
Solid Attenuator
after last Undulator Segment in
Front-End Enclosure (FEE)
Gas Attenuator
Gas Detector
Beam-Based K Measurement Components
See presentations by Tompkins and Bionta
June 16, 2008
LTU/Undulator Commissioning Plans
12
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
X Ray Diagnostics (FEE)
5 mm
diameter
collimators
Gas
Detector
Hard x-ray
Monochromator
(K Spectrometer) Direct Imager
Solid
Attenuator
e-
Slit
Gas
Detector
Muon
Shield
system
NFOV
Total
Energy
Thermal
Detector
WFOV
Hard X-Ray
Offset mirror
system
Start of
Experimental
Hutches
Gas
Attenuator
June 16, 2008
LTU/Undulator Commissioning Plans
Soft X-Ray
Offset mirror
See
13
Nuhn,and
SLAC
/ LCLS
presentationsHeinz-Dieter
by Tompkins
Bionta
nuhn@slac.stanford.edu
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:
C
total spontaneous energy / pulse
spontaneous beam direction
temporal variation in spontaneous beam parameters
spatial distribution around first spontaneous harmonic
Limited capability
spontaneous radiation spectrum
using K
wavelength of first harmonic
Spectrometer
first harmonic wavelength spread
Characterize radiation from each individual Undulator
Measure relative K of Undulator pair.
June 16, 2008
LTU/Undulator Commissioning Plans
14
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
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.
undulator segments (33 total)
segments under test
June 16, 2008
LTU/Undulator Commissioning Plans
C
15
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
Angle-Integrated Spontaneous Spectrum for 2 Undulators with DK/K = -0.2 to +0.2%
C
Dj = 0
~106 photons/nC/0.01%BW
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
June 16, 2008
LTU/Undulator Commissioning Plans
DK/K = 0%
DK/K = -0.2%
16
Heinz-Dieter Nuhn,Simulations
SLAC / LCLS
P. Emma
nuhn@slac.stanford.edu
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
Find SASE signal using Direct Imager
Use Laser-Heater modulation to control gain
(7 Hz Lock-In Detection) if necessary
Repetition rate of 30 Hz (to support Lock-In Detection)
Optimize gain (through electron beam quality and BBA)
Measure gain length etc…
June 16, 2008
LTU/Undulator Commissioning Plans
17
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
FEL Measurements
D
Measurements along undulator
Saturation
Intensity (LG, Saturation)
Exponential
Gain Regime
Measurements after undulator
Photon wavelength
Photon wavelength spread
Undulator Regime
Pulse intensity
Pulse duration
1 % of X-Ray Pulse
Pulse centroid and direction
Spatial distribution
Jitter
June 16, 2008
LTU/Undulator Commissioning Plans
Electron Bunch
Micro-Bunching
18
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
SASE Characterization with FEE Diagnostics
D
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
June 16, 2008
LTU/Undulator Commissioning Plans
19
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
Measurement of SASE Gain Length Using Rollout
D
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.
June 16, 2008
LTU/Undulator Commissioning Plans
20
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
Summary
Plans for LTU/Undulator commissioning have been worked
out and include
A
B
C
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
D
Gain length measurements will use FEE x-ray diagnostics combined
with z-dependent SASE gain cut-off
June 16, 2008
LTU/Undulator Commissioning Plans
21
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
End of Presentation
June 16, 2008
LTU/Undulator Commissioning Plans
22
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
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 (Loos)
Beam-Based Alignment of the FEL Undulator (Loos)
Beam-Finder Wire Application – Centering & Emittance (Loos/Nuhn)
K-Measurement Application (Welch/Nuhn)
There will probably be more …
June 16, 2008
LTU/Undulator Commissioning Plans
23
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
Undulator Segment and TLD Replacement Program
2009
June 16, 2008
LTU/Undulator Commissioning Plans
2010
24
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu
Measurement of SASE Gain Length with
Trajectory Distortion
D
Quadrupole Displacement
at Selectable Point along
Undulator
GENESIS Simulations by Z. Huang
June 16, 2008
LTU/Undulator Commissioning Plans
25
Heinz-Dieter Nuhn, SLAC / LCLS
nuhn@slac.stanford.edu