flash: the first soft x-ray fel operating two undulator ... filesiegfried schreiber | pitz...
TRANSCRIPT
FLASH. Free-Electron Laser
in Hamburg News from FLASH
FLASH: the first soft X-ray FEL operating two undulator beamlines simultaneously
Siegfried Schreiber, DESY
PITZ Collaboration Meeting Zeuthen, Nov 24-25, 2015
FLASH1 FLASH2: 1 pulse
0 50 100 150 200 250
Maximum
Actual
Average
FLASH1: 250 pulses
Bunch number
Ener
gy (μ
J)
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg FLASH 2015: Year of Celebrations
> 15 years of FEL lasing at DESY First lasing (109 nm) of Tesla Test Facility on Feb-22, 2000
> 10 years of SASE at FLASH First lasing (32 nm) of FLASH on Jan-14, 2005
> 10 years of FEL user operation at FLASH User operation started in summer 2005 as the first
FEL user facility in VUV wavelengths worldwide
> 5 years of SASE in the water window at FLASH Lasing at 4.12 nm on Sep-25, 2010
> 1 year of simultaneous operation First lasing of FLASH2 (~ 40 nm) on Aug-20, 2014,
FLASH1 lasing simultaneously with 250 pulses
Lasing with three beamlines simultaneously, with the same bunch in sFLASH and FLASH1 in August 2015
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg FLASH Layout
> TESLA type superconducting accelerating modules 1.3 GHz > FLASH1 fixed gap undulators > 3rd harmonic sc module 3.9 GHz
> Normal conducting 1.3 GHz RF gun > Ce2Te cathode > Two Nd:YLF based ps photocathode lasers
> FLASH1 Experimental Hall
> Extraction to FLASH2 > FLASH2 variable gap undulators
315 m
5 MeV 150 MeV 1250 MeV
Bunch Compressors
450 MeV
Accelerating Structures RF Stations
Lasers RF Gun
Soft X-ray Undulators sFLASH
FEL Experiments
Photon Diagnostics
Beam Dump
THz FLASH1
> FLASH2 Experimental Hall
Albert Einstein
Kai Siegbahn
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg FLASH1 Parameters 2014 / 2015
> more than 220 publications on photon science at FLASH, many in high impact journals
FEL Radiation Parameters
Wavelength range (fundamental) 4.2 – 52 nm Average single pulse energy 10 – 500 µJ Pulse duration (FWHM) < 50 – 200 fs Peak power (from av.) 1 – 3 GW Pulses per second 10 – 5000 Spectral width (FWHM) 0.3 - 2 % Photons per pulse 1011 – 1013 Average Brilliance 1017 – 1021 B* Peak Brilliance 1029 – 1031 B*
* photons/s/mrad2/mm2/0.1%bw
Ene
rgy
(µJ)
Bunch number
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg
38 nm 80 nJ
Cascaded SASE in sFLASH and FLASH1 + FLASH2
> A big step towards seeding in sFLASH truly parallel to FLASH1 operation
20 nm
13.7 nm 75 µJ
> SASE lasing achieved at the same time in all three beamlines
> Cascaded lasing in sFLASH and FLASH1
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg FLASH operation June – September 2015
Scheduled weekly maintenance 1.3% 36 h
User runs 55.0% 1572 h
Studies 43.7% 1248 h
SASE delivery 72.4% 1138 h
Tuning + Set-up 19.8% 311 h
Down 4.1% 65 h
26.05.2015 - 21.09.2015 (119 days = 2856 hours)
Repair personnel interlock system (broken due to a lighting strike) 3.7% 58 h
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg Downtime June – September 2015
0
5
10
15
20
25
30
35
40
22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38
Downtime
Dow
ntim
e (%
)
Personnel interlock system broken due to a thunderstorm (lightning strike)
Week
User Block 1 User Block 2 User Block 3
> 26.05.2015 - 21.09.2015: 2820 operation hours
Total down: 233 h (8.3%), of which 97 h due to lightning strike (broken personnel interlock system); Downtime w/o lightning strike: 136 h (4.8%)
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg Downtime
0
5
10
15
20
CW 22 CW 24 CW 27 CW 28 CW 29 CW 30 CW 36
13121110987654321
1 LLRF (mainly RF-gun, in CW 22 also cooling problems of rack ACC139 ) 2 Technical problem of vacuum valve 4EXP 3 RF-4 and RF-5 off due RF leakage interlock (caused by window teststand RF-station) 4 MPS modul (BIS gateway) blocks beam (Output Module of BIS plc mechanically damaged) 5 RF-2 Flow HVP (fuse for FUG PS broken) 6 Waveguide system of RF-gun 7 Photon diagnostics (movement of YAG screen) 8 RF-5 (SPS) 9 Water cooling RF-2 and RF-3 (wrong action during cooling-tower maintenance) 10 Master oscillator 108 MHz; reason found to be a broken cable 11 Cryo compressor failure 12 RF-39 Modulator interlock switch error (difficult to find the problem) 13 Miscellaneous
Dow
ntim
e (h
ours
)
LLRF LLRF LLRF MO Cryo Ph. Diag. MPS
RF39
Waveg. Gun
RF-5
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg
FLASH 2 FLASH1
Many slides on FLASH2 from B. Faatz
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg FLASH2 Undulator Beamline
> 12 variable gap undulators period 31.4 mm
K-value 0.5 – 2 (rms)
segment length 2.5 m
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg
Spectrum Profile
Beam position Intensity
Beam Position
FLASH2 Photon Diagnostics Beamline
> Final version of photon diagnostics beamline in FLASH2 tunnel installed 3 months interruption of FLASH2 operation in January – April 2015 Basic photon beam diagnostics (GMD, spectrometer) are now working Beamline construction in the hall started
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg FLASH2 Experimental Hall – Kai Siegbahn Hall
> Installation of photon diagnostics and first two beamlines in 2015/16
first installations
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg FLASH2 with SASE record
> 600 µJ reached @15 nm – a new record for FLASH
> Studies on tapering the undulators
> We observed a kink in the undulator beamline → survey next week
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg Realization of Simultaneous Operation
> Fast kicker and Lambertson septum to extract a part of bunch train to FLASH2
> Two injector lasers: FLASH1 and FLASH2 bunch pattern and bunch charge selected independently
> Flexible RF-system: amplitude and phase adjusted - in certain limits - independently for FLASH1 and FLASH2
FLASH1
FLASH2
RF-pulse amplitude
300 μs 450 μs
FLASH1
RF-pulse flat-top 800 μs
30 μs (kicker) 99 ms (10 Hz rep.rate) FLASH1
FLASH2
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg Control system (status November 2014).
Main tuning panel
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg Control system (status May 2015).
New: Slow RF Feedback Charge Feedback
Main tuning panel
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg Control system (status November 2015).
New: Online Energy Monitor LLRF learning FF
Main tuning panel
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg Undulator Control (status November 2014).
Set undulator gaps based on beam energy and desired wavelength. All undulators characterized individually.
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg Undulator Control (status May 2015).
Set undulator gaps and automatically adjust phase shifters to match, including orbit correction.
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg Undulator Control (status November 2015).
Added tapering (in different groups) and global phase change.
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg Tunability.
FLASH1: 13.57 nm for users
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg Tunability.
FLASH1: 13.57 nm for users FLASH2: large variation in intensity from 350 to 1 µJ
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg Tunability.
0
50
100
150
200
250
300
350
400
10 20 30 400
100
200
300
400
Puls
Ener
gy (m
J)
Wavelength (nm)
FLASH1: 13.57 nm for users FLASH2: Wavelength scan from 40 to 10 nm
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg
RF Gun
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg
RF gun controlled by a MTCA.4 based LLRF system since Jan 2015
RF Guns operated at FLASH since 2004
2004
2009
1/2010
6/2010 9/2011
6/2012
Gun2: 5 Hz, 3.5 MW, 350 µs, 5 kW, 680 GJ Window: G29
Gun4.2: 10 Hz, 3.9 MW, 400 µs, 15 kW, 1200 GJ
Window break down; → G67 Window break down; → G29
Window: Gxx
Gun4.1: 10 Hz, 4 MW, 550 µs, 21 kW, 930 GJ
3/2013 Window: G29 Gun3.1: 10 Hz, 5 MW, 550 µs, 27 kW, 1700 GJ(*)
Gun2 breakdown
Gun4.2 breakdown 5/2012
Window: Thales 5 4/2014 Window leak; → G64
Integrated RF-power
Gun 2
Gun 4.2
Gun 4.1
Gun 3.1
No breakdown events or other trips since 8-Jun-2014
(*) until 24-Nov-2015
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg RF Gun Low Level RF
> LLRF now based on MTCA.4 standard
> System identification performed Model found and controller designed
large loop latency compared to system bandwidth ~1.4 µs
> Runs smooth and stable
> Includes learning feedforward
Feedback gain currently not sufficient to achieve a phase stability of dφ < 0.01 dg
> Features additional protection mechanisms amplitude limiter, fast switch off
Regulation performance (rms)
Intra pulse (flattop )
Pulse to pulse (960 consecutive pulses)
Amplitude dA/A (%) 0.008 0.008
Phase dφ (dg) 0.007 0.076
Goal: < 0.01% in amplitude and < 0.01 dg (rms) in phase
OK
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg Cascaded Control Scheme for the RF Gun
1. Water temperature regulation
> Speed ~ Hz
PI feedback controller with PLC
Sensor: temperature at the iris
Actuator: cold water valves (combination of fast and slow)
2. Temperature regulation with RF
> Speed: MHz to Hz
MIMO feedback controller
Sensor: virtual probe (Vfwrd, Vrfl)
Actuator: RF power via Input to RF via vector modulator (pulse length)
S. Pfeiffer et al. Goal: Fast compensation of temperature drifts Fast Actuator Fast and precise temperature information
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg Long term data with cascaded feedbacks
> Phase sampled at 3
positions during flattop (700
μs, 900 μs, 1100 μs)
> Without and with RF based
feedback (pulse length)
flatto
p sa
mpl
ing
posi
tion
Large improvement w/o: dφ > 0.050 dg with: dφ <0.016 dg
15.9 mdg rms
10.9 mdg rms
9.6 mdg rms
52.8 mdg rms
31 mdg rms
21.3 mdg rms
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg
Cathode
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg Cs2Te Cathodes
> High initial quantum efficiency ~10 … 15 %
> Excellent lifetime > 1 year at FLASH
> Preparation systems at LASA, Milano and DESY, Hamburg
UHV transport boxes
> Requires UV laser 275 … 250 nm
Laser
e- -beam
Mo plug
Thin film of Cs2Te on Mo plug
16 mm
5 mm
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg QE map Cathode 73.3 at FLASH
> Cathode 73.3 inserted 4-Feb-2015, initial QE 12.4% 26-Jun-2013, LASA
> Similar QE pattern as previous cathode 618.3
4-Feb-2015 fresh QE=10.3 %
73.3 73.3 73.3
73.3 73.3
3-Mar-2015 QE=10.3 %
18-Aug-2015 QE=11 %
28-Sep-2015 QE=8.9 %
19-Nov-2015 QE=7.2 %
> Quick QE degradation in the center
> Rest follows slowly
> This time at a high 7% level
No vacuum issue as for 618.3
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg QE cathode 73.3 at FLASH
cw 26-Jun-2013
26-Jun-13
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg
Outlook
Siegfried Schreiber | PITZ Collaboration Meeting | Nov-24, 2015
FLASH. Free-Electron Laser
in Hamburg FLASH 2016
> Both FLASH1 and FLASH2 in regular user operation
> 2 user periods: January – June and July – December, 2016 As before: User blocks alternating with study blocks
> No major changes on the FLASH facility expected Resource demanding installations and technical works avoided
until installations of the European XFEL finished
> FLASHForward installations in FLASH2 tunnel (now, mid 2016, and end 2016) – electron driven plasma acceleration A. Aschikhin et al. NIMA 806 (2016) 175