African Easterly Waves during 2006 – Objective diagnostics and Overview.
Overview of FERMI Diagnostics
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Transcript of Overview of FERMI Diagnostics
M. Ferianis feb 2006 @ UCLA
Overview of FERMI Diagnostics
M. Ferianis feb 2006 @ UCLA
FERMI @ ELETTRA
M. Ferianis feb 2006 @ UCLA
FERMI footprint
M. Ferianis feb 2006 @ UCLA
FERMI main parameters
M. Ferianis feb 2006 @ UCLA
FERMI layout (...work in progress)
Laser heater
X-band linearizerspreaderEnergy/ H, V collimatorsdump
M. Ferianis feb 2006 @ UCLA
accurate photo-injector characterisation:
emittance, charge profile, energy spread seeded FEL scheme: whole bunch / fresh bunch (bunch core)
calls for slice measurements:
longitudinal charge profile, emittance, energy spread transverse and longitudinal overlap between e- beam and laser
high resolution BPM and bunch arrival monitors
shot-to-shot feedbacks stability of output FEL radiation mm to sub-mm bunch length; currently two options:
medium bunch: LB= 0.21mm (700fs) short FEL pulse
long bunch: LB= 0.57mm (1.9ps) long FEL pulse
Guidelines of diagnostics for FERMI
M. Ferianis feb 2006 @ UCLA
Some relevant beam parametersfor diagnostics
*calculated assuming a normalized emittance of 1.2 mm mrad
Medium Bunch
Energy
[MeV]
Charge
[nC]
Bunch Length
[ps / mm, FWHM]
Transverse Size*
3xx,v[mm]
Entrance BC1 220 0.8 5.4 / 1.620 500
Exit BC1 220 0.8 2.6 / 0.780 300
Entrance BC2 600 0.8 2.6 / 0.780 300
Exit BC2 600 0.8 0.7 / 0.210 180
Long Bunch
Entrance BC1 220 1 11 / 3.3 500
Exit BC1 220 1 5.6 / 1.68 300
Entrance BC2 600 1 5.6 / 1.68 300
Exit BC2 600 1 1.9 / 0.57 180
M. Ferianis feb 2006 @ UCLA
Injector diagnostic beamline BC1 diags 1st RF deflector @ 220MeV (down-stream BC1) BC2 diags 2nd RF deflector @ 1.2 GeV pre-FEL diagnostic station (downstream the spreader) post-modulator diagnostic station intra-radiator diagnostics (multipurpose pop-ins) post radiator diagnostic station (FEL diags)
Guidelines of diagnostics for FERMI
M. Ferianis feb 2006 @ UCLA
Currently addressed issues on Diagnostics
review of FERMI parameters for diags. the team @ ELETTRA: dynamically growing... overview of main FERMI diagnostics and associated
measurements integration of diagnostics into the machine, i.e. defining:
dedicated machine optics vacuum chamber x-sections alignment strategy RF power needs for diags optical clock (laser pulse)
Conceptual Design Report write-up
M. Ferianis feb 2006 @ UCLA
Gun S0A/BLaserHeater XLINAC1
BC1 BC2
LINAC2 LINAC3 LINAC4 SPRDFEL1
FEL2
Gun / injector Diagnostics
Gun:
•Energy/energy spread •Charge•Spot size•Position •Bunch length•Thermal emittance
M. Ferianis feb 2006 @ UCLA
Gun S0A/BLaserHeater XLINAC1
BC1 BC2
LINAC2 LINAC3 LINAC4 SPRDFEL1
FEL2
Laser heater based diagnostics
775 nm seed laser derived from 1550 nm timing signal 120 kW, 10 ps
Cross-polarized 5-period undulators
Matching quads into heater
Matching quads into linac
YAG screen, BPM
YAG screen, BPM
Laser Heater :
Electron beam timing relative to optical pulse
Electron beam current profile
Slice emittance
W.Graves, MITS.Spampinati, ELETTRA
M. Ferianis feb 2006 @ UCLA
Energy, Energy jitter, Vertical slice emittance: BMP –collimator -screen
Bunch length monitor: CSR output power detection to feedback loop
Micro-bunching: CSR output for detection by THz spectrometer.
Bunch arrival time measurements: fs Streak camera (ref pulse)
wide band ring electrode with EO acquisition
Bunch length, compressor tuning:
• BC1: 1st RF Deflector, streak camera for OSR
• BC2: 2nd RF deflector, EO sampling
Gun S0A/BLaserHeater XLINAC1
BC1 BC2
LINAC2 LINAC3 LINAC4 SPRDFEL1
FEL2
BC1 & BC2 Diagnostics
M. Ferianis feb 2006 @ UCLA
Diagnostics station at the end of linac :
Vertical and Horizonthal RF deflecting cavity:
Slice emittanceCSR effect on horizonthal emittanceSlice Energy Spread
EOS bunch arrival time monitor:
Bunch arrival time
Arrival time jitter
Bunch length
Features: single shot (SLAC spatial convertion scheme, 100fsec resolution, MLO or SEED laser
pulses as a probe)
Overview of FERMI @ Elattra Diagnostics
Gun S0A/BLaserHeater XLINAC1
BC1 BC2
LINAC2 LINAC3 LINAC4 SPRDFEL1
FEL2DIAGS
M. Ferianis feb 2006 @ UCLA
FEL 1&2 :
Entrance of modulators:
X,Y position and divergence: high precision cavity BPM
Intra - radiators:
e-beam and FEL radiation position and spot size: pop-in station with YAG screens
e-beam X,Y position: cavity or button BPM
microbunching and power growth: OTR/CTR
monitorinig during operation CDR
Exit of last radiator FEL radiation: (under development by user group):
Single shot Spectral distribution monitor
FEL radiation arrival time by respect to user laser determined by cross correlation
techniques (De Silvestri) and advanced streak cameras.
Overview of FERMI @ Elattra Diagnostics
Gun S0A/BLaserHeater XLINAC1
BC1 BC2
LINAC2 LINAC3 LINAC4 SPRDFEL1
FEL2DIAGS
M. Ferianis feb 2006 @ UCLA
EB= 240 MeV; n=1.5 mm mrad;a=20 mm vg/c=0.0312 (L=1m=100ns)a=12.5 mm; vg/c=0.0123(L=1m=270ns)fRF=2.998 GHz;D=45 m; S=45 m; =90 deg;
Traveling wave deflectorperformances for low energy case
Long bunch: 1.5 mm
Short bunch: 0.4 mm
Ldef=2m
M. Ferianis feb 2006 @ UCLA
EB= 1.2 GeV; n=1.5 mm mrad;a=20 mm, =1 F=0.85sa=12.5 mm, =1 F=1.0sfRF=2.998 GHz;D=45 m; S=45 m; =90 deg;
Standing wave deflector: performances for high energy
case
M. Ferianis feb 2006 @ UCLA
Cavity BPMin collaboration withM Poggi, INFN PD
Beam pipe radius: to be defined according to Vacuum & Zbeam current value R=6mm; ID gap (vacuum side) calls for R=3.5mm
Extraction waveguide radial position: to be checked with simulationOptimum position for the RF connecotr on the waveguideSignal amplitude dependance on Qbunch (analytical eval.) Achievable mechanical accuracy on prototype: 10mSetting up the RF test bench (Network An.@20GHz):
BPM rigidly fixed to supportcoaxial moving wire, over ±1mm, acuracy and reproducibility <2m
prototype issues: no UHV, flanged + RF sliding contacts, equipped with SMA connectors (DC to 18 GHz)
M. Ferianis feb 2006 @ UCLA
Principle:• Isolated impedance-matched Ring Electrode
installed in a „thick Flange“• Broadband, Position independent Signal• One installed after the Gun, each magnetic Chicane
(both BCs, the Collimator + before Undulator)• BC´s: Energy Fluctuations -> Phase Fluctuations
TOF Measurement: Resolution ≈ 0.2° or 0.4 ps• Fast timing signals with sub ps resolution• Very simple design of pickup• Two output signal provided (left & right)
~550 mV/psPhase Monitor
Phase monitor (collaboration with Desy)
Courtesy: H. Schlarb, F.Löhl
M. Ferianis feb 2006 @ UCLA
EO acquisition of the wide band ring electorde signal
~ 1.3 GHz
DAC
DOOCS
MasterLaser
Oscillator
piezo-fiber-
stretcher
piezo-controller
~~~
1.3 GHz 10 GHz
200 MHz~~~
81 MHz limiter
ADC100 MHz
12 / 14 Bit
clock trigger
DOOCS
phasemonitor
EOM200 MHz
bias-voltage
10 kHz
VM
Courtesy: H. Schlarb, F.Löhl
~550 mV/ps
12 dB
MLORF master
BPhM
Mach-Zehnderinterferometer
Later: limiter
M. Ferianis feb 2006 @ UCLA
Impact from vacuum chamber sections
Type Dimensions
Linac circular D=30 mm
Compressors rectangular W=60mm,
H=30mm
Undulator elliptical H=7mm
W= tbd (vacuum)
M. Ferianis feb 2006 @ UCLA
Timing and Synchronization