XFEL 2004 at SLAC m. ferianis Synchronization and phase monitoring: recent results at ELETTRA • Synchronization experiment using light sources currently available at Elettra • Streak camera measurements • CW Phase measurements • Status of the “light-to-light” jitter monitor • Single event phase measurement Mario Ferianis , Miltcho Danailov SINCROTRONE TRIESTE, Italy
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XFEL 2004 at SLAC m. ferianis Synchronization and phase monitoring: recent results at ELETTRA Synchronization experiment using light sources currently.
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XFEL 2004 at SLAC m. ferianis
Synchronization and phase monitoring: recent results at ELETTRA
• Synchronization experiment using light sources currently available at Elettra
• Streak camera measurements• CW Phase measurements• Status of the “light-to-light” jitter monitor • Single event phase measurement
Mario Ferianis, Miltcho Danailov
SINCROTRONE TRIESTE, Italy
XFEL 2004 at SLAC m. ferianis
Radiation sources currently available at Elettra
• Sources presently available at ELETTRA:– Bending Magnet S12.2 (diagnostic beam line)
• FWHM=30ps tREP 1MHz
– Storage Ring - FEL• FWHM=8ps tREP 4MHz,
– Table top fs-lasers: Ti:Sa and Cr:LiSaf• FWHM110fs tREP 100MHz
• The SR-FEL is “naturally” synchronized to ELETTRA• The table-top lasers may be locked to an external RF
XFEL 2004 at SLAC m. ferianis
Synchronization experiment of a fs Laser to Elettra Sources
Bandpass filter response to 4 Bunch beam,f0=83.275MHz, BW 6.5MHz.
XFEL 2004 at SLAC m. ferianis
AD8302 phase measurement: 6.5MHz filter output vs. reference
(83.275MHz)
V=330mV 33deg
Plot of the phase difference measured with 1GHz scope [deg]
230
240
250
260
270
280
290
0 100 200 300 400time [ns]
XFEL 2004 at SLAC m. ferianis
Narrowband (BW=2.5MHz)bandpass filter
XFEL 2004 at SLAC m. ferianis
FERMI Phase Measurements
• The term “Phase measurement” generally refers to measuring the phase of a signal w.r.t. a reference.
• Rigorously, we can speak about phase when dealing with sinusoidal signals, eventually sinusoidal bursts.
• For FERMI applications, two different “phase” measurements* are needed:– sinusoidal to reference (CW/CW burst measurement)
– pulse to reference (single event measurement)
• For pulsed signals, the phase difference can be defined as the time interval bewteen pulse arrival and next zero crossing of the reference signal.
• The most critical measurement is the second one due to:– required (sub-) ps resolution
– ultra short pulses of limited amplitude (low energy signals)
– low repetition rate (1 to 100Hz)
* APL - Dip. Elettronica ed Informatica, Trieste University and AllTEK Innovation s.r.l.
XFEL 2004 at SLAC m. ferianis
Proposed scheme for single event phase measurement
Pulse stretcher
Beam pulsesignal
Reference signal
“0” Xingdetector
(low jitter)Hold off
Hold off
Time interpolator(SiGe logic)
Pulse stretcher
“0” Xingdetector
(low jitter)
APL - Dip. Elettronica ed Informatica, Trieste University and AllTEK Innovation
XFEL 2004 at SLAC m. ferianis
Zero X-ing detector prototypetests with Pulse Generator:
tPULSE=300ps; APULSE PK-PK=90mV; fREP=10kHz
TRIGGER
CSA803CSampling
Scope
BW=20GHz
INPUT
HP8131A500MHz
Pulse Generator 10mV/div100ps/div
JitterRMS=1. 37ps
TRIGGER
CSA803CSampling
Scope
BW=20GHz
INPUT
HP8131A500MHz
Pulse Generator
“0” X-ingdetector
IN OUTunder
test
100mV/div100ps/div
JitterRMS=1.94ps
Apk-pk=600mV*10 (20dB att) =6V
APL - Dip. Elettronica ed Informatica, Trieste University and AllTEK Innovation s.r.l.
XFEL 2004 at SLAC m. ferianis
tRISE =18pstPULSE =30psAPULSEpk-pk=250mV
Zero X-ing detector prototype tests @ fREP=10Hz
fs laser + Pockels Cell + 25GHz Photodiode
New FocusPhoto DiodeBW=25GHz
“0” Xingdetector
under test
IN OUT
TEK Real time ScopeTRIGGER
CH1
BW=1GHz
CH2
Cr:LiSAFfs laser
PockelsCell
HVdriver
SPLITTER
Amplifier7GHz
Pulsegenerator
-10dB
2Vpk-pk*3.17=6.3V
APL - Dip. Elettronica ed Informatica, Trieste University and AllTEK Innovation
XFEL 2004 at SLAC m. ferianis
Future work
• To complete direct light-to-light phase measurements in 4B mode– Bending Magnet to external fs laser– Bending Magnet to SR-FEL– SR-FEL phase during Q-switch w.r.t. a non modulated RF (?)
• To complete jitter reduction work in the Profile Monitor hutch• To implement phase measurement at low rep rate
– 10Hz i.e. FERMI
• To characterise laser jitter in fiber optic transmission• To study the feasibiltiy of an in-house improved version of