Transcript Document 7125481

SLAC National Accelerator Laboratory
LCLS Commissioning Status
P. Emma for The LCLS Commissioning Team
LCLS FAC Meeting
November 11, 2008
Machine Performance
Estimated FEL Power
Ultra-Short Pulse Possibilities
Plans for 2009
LCLS
Results published in FEL’08 and Linac’08 proceedings
Nov. 11, 2008
LCLS Commissioning Status
1
Paul Emma
[email protected]
SLAC National Accelerator Laboratory
Phase-II Commissioning Highlights (2008)
Injector Commissioning: Apr-Aug, 2007 (DONE)
Phase-II Commissioning: Dec-Aug, 2008 (DONE)
Great drive-laser uptime (99%) and good performance
Projected emittances 0.7-1.6 mm at 0.25 nC, 10 GeV
Routine 30-Hz e- to 14 GeV (~24/7 with ~90% up-time)
Bunch compression fully demonstrated down to 1-2 µm
New cathode installed with greatly improved thermal emittance
20-pC bunch with 0.14-µm emittance (and 2-fs length?)
Electron bunch appears bright enough to drive 1.5-Å FEL
Phase-III commissioning started Nov. 3, 2008 – X-rays by July ‘09
Nov. 11, 2008
LCLS Commissioning Status
2
Paul Emma
[email protected]
SLAC National Accelerator Laboratory
Design and Typical Measured Parameters (Aug. 2008)
Parameter
symbol
design
measured
unit
gmc2
13.6
13.6
MeV
Bunch charge
Q
1
0.25
nC
Initial bunch length (rms)
sz0
0.9
0.75
mm
Final bunch length (rms)
szf
20
8-10
mm
Projected emittance (injector)
gex,y
1.2
0.7-1.0
μm
Slice emittance (injector)
gesx,y
1.0
0.6
μm
Projected emittance (linac end)
geLx,y
1.5
0.7, 1.6*
μm
f
120
30
Hz
RF gun field at cathode
Eg
120
115
MV/m
Laser energy on cathode
ul
250
20-150
μJ
Laser diameter on cathode
2R
1.5
1.2
mm
Cathode quantum efficiency
QE
6
0.7-7
10-5
Final linac e- energy
Single bunch repetition rate
Nov. 11, 2008
LCLS Commissioning Status
* horizontal slice emittance likely < 1 µm
3
Paul Emma
[email protected]
SLAC National Accelerator Laboratory
Bunch Compression & CSR Measured after BC2 (0.25 nC)
nominal
sz < 5 mm
sz  2 mm
old screen used
sz > 25 mm
L2
BC2
(4.3 GeV)
Nov. 11, 2008
LCLS Commissioning Status
TCAV
(5.0 GeV)
4
550 m
4 wires
BSY
(14 GeV)
Paul Emma
[email protected]
SLAC National Accelerator Laboratory
Emittance Near End of Linac Over Long Weekend
g(exey)1/2 = 1.04 mm
long
weekend
run at
0.25 nC
with no
tuning
(3.3 days) May 24, 2008 00:01 to May 27 09:00
Nov. 11, 2008
LCLS Commissioning Status
5
Paul Emma
[email protected]
SLAC National Accelerator Laboratory
Beam Appears Bright Enough for FEL Saturation at 0.15 nm
M. Xie method, with wakes
FEL Power
3D Gain Length
Calculation based on measured end-of-linac projected emittance values, measured peak
current, and design undulator parameters (assuming undulator alignment and 0.01%
rms slice energy spread – not yet measurable)
Nov. 11, 2008
LCLS Commissioning Status
6
Paul Emma
[email protected]
SLAC National Accelerator Laboratory
New Cathode: Time-sliced x-Emittance at Very Low Charge
TAIL
0.14 µm
(not same data)
20 pC, 135 MeV, 0.6-mm spot diameter, 400 µm rms bunch length (5 A)
Nov. 11, 2008
LCLS Commissioning Status
7
Paul Emma
[email protected]
SLAC National Accelerator Laboratory
Measurements and Simulations for 20-pC Bunch at 14 GeV
sz  1 mm ?
LiTrack
(no CSR)
8 kA?
Photo-diode signal on OTR after BC2 shows
minimum compression at -34.5 deg L2-linac phase.
SIMULATED FEL PULSE
Y. Ding
1.5 Å,
3.61011 photons
Ipk = 4.8 kA
ge  0.4 µm
LCLS FEL simulation at 1.5 Å based on measured
injector beam and Elegant tracking with CSR at 20 pC.
Horizontal projected emittance measured at 10
GeV, after BC2, using 4 wire-scanners.
Nov. 11, 2008
LCLS Commissioning Status
8
Paul Emma
[email protected]
SLAC National Accelerator Laboratory
120-Hz RF & Controls Testing Done
(Gun, L0a, L0b, L1-S, & L1-X)
Measured 120-Hz “Timeslot” phase jitter for all injector RF stations:
Gun, L0a, L0b ~0.8 deg rms (tol. = 0.1 deg)
L1S ~0.17 deg rms (tol. = 0.1 deg)
L1X ~0.3 deg rms (tol. = 0.5 deg)
Observe ~1 deg difference on every 4th pulse (L0a, L0b, L1X)
Measurements confirmed with old SLC control system and new
Beam Synchronous Acquisition system
More feedback development is needed (beam-based and RF-based)
Radiation measured are below posted limits at each klystron
Gun temperature and vacuum response OK at 120 Hz
M. Stanek
Nov. 11, 2008
LCLS Commissioning Status
9
Paul Emma
[email protected]
SLAC National Accelerator Laboratory
The LCLS Laser Heater is Ready (except undulator)
Beam through chicane already…
Controls
ready
Nov. 11, 2008
LCLS Commissioning Status
10
IR & e- beams on
OTR screens now
Paul Emma
[email protected]
SLAC National Accelerator Laboratory
OTR screens (7)
YAG screens (7)
Wire scanners (7)
Dipole magnets (8)
Beam stoppers (2)
S-band RF acc. sections (5)
RF Gun
Solenoid
Laser-Heater
Gun
Spectrometer
Emittance
Screens/Wires
Emittance
Screen/Wires
RF
Deflector
2-km point in 3-km SLAC
linac
L1S
135-MeV
Spectrometer
135 MeV
LCLS Commissioning Status
TD11
stopper
250 MeV
RF Deflector (LOLA) + special
lattice configuration in
spectrometer allows fine
measurement of time-sliced
energy spread (to <6 keV)
Nov. 11, 2008
X-band RF BC1
acc. section
11
sE  6 keV rms (40 mm)
Paul Emma
[email protected]
SLAC National Accelerator Laboratory
New emittance
data at 135 MeV
taken on Nov. 8,
2008 just 2 days
into the turn-on
gex = 0.61 µm
q = 0.25 nC
gey = 0.67 µm
Nov. 11, 2008
LCLS Commissioning Status
12
Paul Emma
[email protected]
SLAC National Accelerator Laboratory
Important Dates for 2008/2009 Commissioning
Nov. 3, 2008:
Startup (establish beam to end of linac again)
Dec. 3, 2008:
Install laser-heater undulator (?)
Dec. 15, 2008:
First beam through LTU & to dump?
Dec. 19, 2008:
SLAC shuts down for holidays
Jan. 5, 2009:
Startup again (establish beam in LTU & dump)
March 2, 2009:
Install ~25 undulators & PPS cert. (~2 wks)
May 14, 2009:
First beam in FEE
July 2009:
Photons in NEH
August 2009:
Start AMO Experiment
Nov. 11, 2008
LCLS Commissioning Status
13
Paul Emma
[email protected]
SLAC National Accelerator Laboratory
CD-4 (7/31/2010)
First Light in FEH
FEH Hutch BO
X-Rays in NEH
First Light in FEE
Install Undulators
FEE/NEH Install
PPS Cert. LTU/Dump
now
LTU/Und Install
PEP-II run ends
LCLS Installation and Commissioning Time-Line
2008
Linac/BC2
Commissioning
Nov. 11, 2008
LCLS Commissioning Status
Down
PPS
J F M AM J J A S ON D J F M AM J J A S ON D J F M A M J J
Down?
2009
LTU/Und
NEH Ops &
Comm.
Commissioning
Re-establish
FEL/FEE
e- to SL2
Commissioning
14
2010
Nov. 3, 2008
Paul Emma
[email protected]
SLAC National Accelerator Laboratory
LTU/Undulator/FEE/FEL Commissioning
H. Tompkins
+ heater
Nov. 11, 2008
LCLS Commissioning Status
15
Paul Emma
[email protected]