Design of an Infrared Prism Spectrometer for Ultra-Short Bunch Length Diagnosis. Christopher Behrens on behalf of Joe Frisch, Sasha Gilevich, Henrik Loos, and Jen Loos SLAC National Accelerator Laboratory & Deutsches Elektronen-Synchrotron (DESY) APE meeting, 30-11-2010 C. Behrens (SLAC & DESY) Infrared Prism Spectrometer. APE meeting 1 / 18
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Design of an Infrared Prism Spectrometer for Ultra-Short Bunch … · 2013-03-12 · Design of an Infrared Prism Spectrometer for Ultra-Short Bunch Length Diagnosis. Christopher Behrens
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Design of an Infrared Prism Spectrometerfor
Ultra-Short Bunch Length Diagnosis.
Christopher Behrenson behalf of
Joe Frisch, Sasha Gilevich, Henrik Loos, and Jen Loos
SLAC National Accelerator Laboratory & Deutsches Elektronen-Synchrotron (DESY)
APE meeting, 30-11-2010
C. Behrens (SLAC & DESY) Infrared Prism Spectrometer. APE meeting 1 / 18
Outline
1 MotivationUltra-Short Electron Bunches and FEL PulsesDiagnostics and Limitations
2 Radiation Generation and DetectionCoherent Radiation DiagnosticsPyroelectric Detectors
3 Prism SpectrometerBasics and FormulasPotential MaterialsConfiguration and OpticsWavelength Calibration
4 Radiation Input CouplingViewport and Radiation TransportConfiguration and Optics
5 Summary and OutlookSummaryOutlookThe End
C. Behrens (SLAC & DESY) Infrared Prism Spectrometer. APE meeting 2 / 18
Motivation Ultra-Short Electron Bunches and FEL Pulses
Ongoing Tendency of Getting Shorter Electron Bunches• FEL science (user): shorter FEL pulses ⇒ better time resolution.
• Accelerator physics: lower charge ⇒ smaller emittance and less wake fields.
Efforts at Different Facilities• Theoretical Studies and Beam Dynamics Simulations: LCLS, E-XFEL, FLASH, ....
• University of Hamburg started a dedicated project on this topic.
• Experimental Studies: LCLS and FLASH.
• LCLC is already running in short pulse mode with 20 pC and 40 pC.
C. Behrens (SLAC & DESY) Infrared Prism Spectrometer. APE meeting 3 / 18
Motivation Diagnostics and Limitations
It’s working in simulations and experiment, but ...• does it also work as predicted?
• how long are the electron bunches (FEL pulses)?
• what is the shape of the electron bunches?
Diagnostics for Short Bunch Lengths• Transverse Deflecting Cavities ’TCAV’: time domain.
• Resolution with S-band TCAV is not much better than 10 fs.
• X-band TCAV will give better resolution (higher frequency and gradient).
• Special diagnostics like the A-line experiment by Z. Huang et al. at SLAC/LCLS.
• Coherent radiation diagnostics ’CRD’: frequency domain.