john arthur lcls diagnostics and commissioning [email protected] september 22, 2004...
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John Arthur
LCLS Diagnostics and Commissioning Workshop [email protected]
September 22, 2004
Summary of Related Topics from the Miniworkshop on XFEL Short Bunch
Measurement and Timing
John ArthurLCLS
John Arthur
LCLS Diagnostics and Commissioning Workshop [email protected]
September 22, 2004
ICFA Future Light Sources Subpanel Miniworkshop on XFEL Short Bunch Measurement and Timing
Stanford Linear Accelerator Center, July 26 - 30, 2004
http://www-ssrl.slac.stanford.edu/lcls/xfel2004/index.html
Organizers: J. Hastings, P. Krejcik, H. Schlarb, J. Wu
John Arthur
LCLS Diagnostics and Commissioning Workshop [email protected]
September 22, 2004
This workshop will focus on the issues of measuring and synchronizing ultra-short bunches in linac-based FELs. Three primary themes will be addressed at the workshop:
Measurement techniques for the determining the electron bunch length and arrival time.
Measurement techniques, theory and simulation for diagnosing spontaneous undulator and XFEL radiation to determine its temporal profile.
Issues of timing and synchronization of ultra-fast lasers to the electron bunch and RF.
John Arthur
LCLS Diagnostics and Commissioning Workshop [email protected]
September 22, 2004
P. Emma
The workshop featured a concise, eccentric history of American baseball
John Arthur
LCLS Diagnostics and Commissioning Workshop [email protected]
September 22, 2004
X-ray diagnostics of FEL performance
John Arthur
LCLS Diagnostics and Commissioning Workshop [email protected]
September 22, 2004
W. Fawley
Simulations show development of FEL beam in undulator
John Arthur
LCLS Diagnostics and Commissioning Workshop [email protected]
September 22, 2004
V. Sajaev
Typical single-shot spectrum
Average spectrum
long bunch
short bunch
Distinctive spectral fluctuations of FEL pulses
John Arthur
LCLS Diagnostics and Commissioning Workshop [email protected]
September 22, 2004
D. Peter Siddons
At 8 keV, Range of E/E >10-3 possibleResolution of 10-5 possible
Resolution of 10-6 possible with backscattering and asymmetric reflections, but range would be reduced
To resolve LCLS spectrum, need single-shot x-ray spectrometer with resolution of 10-6
John Arthur
LCLS Diagnostics and Commissioning Workshop [email protected]
September 22, 2004
Discussions of x-ray diagnostics and radiation properties
Focused on diagnostics which will help FEL performanceIntensity, propagation of pulse shape, spectrum are all importantSpectral measurement needs dE/E<10-6 to see spikesAbility to turn off undulator sections is vital
Questions:Effect of reflections/aperturing by beam pipeHow chirp helps or hurtsHow to organize dataHow best to correlate x-ray with optical laserHow coherent (spatially) will the LCLS be
John Arthur
LCLS Diagnostics and Commissioning Workshop [email protected]
September 22, 2004
Electron diagnostics for XFELs
John Arthur
LCLS Diagnostics and Commissioning Workshop [email protected]
September 22, 2004
EO Crystal
vvvv
kv
kv
kv
vv
Electro-Optic Sampling encodes electron pulse shape on a laser pulse
John Arthur
LCLS Diagnostics and Commissioning Workshop [email protected]
September 22, 2004
polarizing beamsplitter
laserkvtime
; space tim
etim
e
integrated intensity
integrated intensity
John Arthur
LCLS Diagnostics and Commissioning Workshop [email protected]
September 22, 2004
200mμ
Single-Shotw/ high frequency filtering
iCC
D counts
time (ps)
color representation
Timing Jitter Data(20 Successive Shots)
time (ps)
shot
EOS data from SPPS A. Cavalieri
John Arthur
LCLS Diagnostics and Commissioning Workshop [email protected]
September 22, 2004
Talks on EOS were given by A. Cavalieri, S. Düsterer, H. Loos, A. Winter, D. Reis, and S. Jamison
John Arthur
LCLS Diagnostics and Commissioning Workshop [email protected]
September 22, 2004
An interferometer can be used to autocorrelate Coherent Transition Radiation, giving a measure of electron bunch length
P. Muggli
John Arthur
LCLS Diagnostics and Commissioning Workshop [email protected]
September 22, 2004
Electron bunch measurements using a transverse RF deflector
VV00 20 MV 20 MVzz 50 50 μμm, m, EE 28 GeV 28 GeV
ee
zz
2.44 m2.44 m
cc pp
90°90°
VV((tt))yy
RFRF‘‘streak’streak’
SS-band-band
P. Emma
John Arthur
LCLS Diagnostics and Commissioning Workshop [email protected]
September 22, 2004
Many other talks discussed aspects of timing jitter measurement and control
John Arthur
LCLS Diagnostics and Commissioning Workshop [email protected]
September 22, 2004
General Conclusions
Electron diagnostics seem to be more advanced than x-ray diagnostics
Need to sharpen the requirements for diagnostics
Need to coordinate/share results of experiments
Simulations will play a large role
What’s up with these Cub fans?