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Laser-wire Update. Grahame Blair CLIC Technical Board CERN 29 th June 2010. Commissioning of the PETRA3 Laser-wire Summary of first ATF-ext laser-wire Installation of ATF2 laser wire. www.pp.rhul.ac.uk. The RHUL Team. Academics. Grahame Blair Laser-wire, BDSIM, …
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Laser-wire Update Grahame Blair CLIC Technical Board CERN 29th June 2010 • Commissioning of the PETRA3 Laser-wire • Summary of first ATF-ext laser-wire • Installation of ATF2 laser wire www.pp.rhul.ac.uk
The RHUL Team Academics • Grahame Blair • Laser-wire, BDSIM, … • Stewart Boogert • Laser-wire, low-Q BPM, ATF2… • Pavel Karataev • CDR, CTF3, ATF2 … • Stephen Molloy • RF Simulation, RTML, ATF2… CLIC-related activities PhD students • Robert Ainsworth • RF Simlation, • Thomas Aumeyr • Laser-wire • Nirav Joshi • BPM • Konstantin Lekomtsev • CDR/CTF3 • Maximilian Micheler • CDR/CTF3 • + 2 others to join this year Post-Doctoral RAs • Alessio Bosco • Laser-wire • (Anne Dabrowski) • CTF3, … • Lawrence Deacon • Laser-wire, BDSIM • (Alexey Lyapin) • Laser-wire, BPM, ATF2, …
Laser-wire People DESY : V. Gharibyan, S. Schreiber, K. Wittenburg, K. Balewski JAI@Oxford: B. Foster, N. Delerue, L. Corner, L. Nevay, R. Walczak JAI@RHUL:,T. Aumeyr, G. Blair, S. Boogert, G. Boorman, A. Bosco, L. Deacon, P. Karataev KEK: A. Aryshev H. Hayano, K. Kubo, N. Terunuma, J. Urakawa
PETRAII Detector • Requirements for detector material • short decay time (avoid pile up) • short radiation length • small Moliere radius • Cuboid detector crystals made of PbWO4 • 3x3 matrix of 18x18x150 mm crystals • Energy resolution better than 5%
66 ps 60 ps Q-switched, unseeded Laser Longitudinal Profile • Example of a single shot measurement of the profile500 ps window, resolution 5 ps
Laser Temporal Profile Unseeded Seeded
Laser Pointing Jitter Translates to longitudinal so not relevant Translates into a 1.6 m jitter at the LW IP for Both horizontal and vertical scans
PETRAII Results: Vertical Convoluted profile (takes<50s) Fit to Rayleigh formula
PETRAII Results: Horizontal Convoluted profile Fit to Rayleigh formula
PETRAIII Laser-Wire Installed early 2009 Easy initial commissioning Currently have Laser problems
PETRAIII Laser-wire Breadboard layout Raw scan
ATF Laser-Wire Aiming at micron-scale vertical scans
Effect of Optical Aberrations Where we were running optimum
Pulsed laser performance Profile scans (shows astigmatism) Temporal scans (shows laser pulse length)
Systematic Effects: Fit methods Important to know beam aspect ratio
ATF2 Laser Infrastructure installation • Large laser room on ATF2 shield blocks • Facility for future users • 6 m optical table • Temperature stabilised • Seismic safe
ATF2 Laser Tests Tasks completed: Check laser working (sorted out cooling) – very good Started work on software for DAQ and experiment control Set up temperature logging around laser hut Aligned cw laser into tunnel and through laser-wire IP Completed laser pulse duration measurements Started laser spatial quality measurements Laura Corner Laurie Nevay Stewart Boogert Alex Aryshev (KEK) Interferometric autocorrelation Intensity autocorrelation
Mode-Locked Oscillator Fiber Amplifier Fiber Core 30 m Diode Pump Pw = 12W Pulse Picker RHUL Mode-Locked Laser Current Status Pulse duration: 10 ps Pulse energy: 15 nJ Pulse power: 1.5 kW Repetition rate: 62.5 MHz Average power: 1 W Pulse duration: 10 ps Pulse energy: 10 nJ Pulse power: 1 kW Repetition rate: 1 MHz Average power: 10 mW Possible Improvement Pulse duration: 10 ps Pulse energy: 180 nJ Pulse power: 18 kW Repetition rate: 62.5 MHz Average power: 12 W Pulse duration: 10 ps Pulse energy: 500 nJ Pulse power: 50 kW Repetition rate: 1 MHz Average power: 500 mW
Current Status PETRAII showed good results for an accelerator ring LW PETRAIII laser wire installed and commissioning has Started; however there are currently laser problems ATF-ext: Proof of principle for a BDS LW ATF2 LW has been installed and attempts at signal observation have so far been unsuccessful; there is a very long path for photon extraction (electron extraction not relevant due to relatively small Compton energy loss) Laser R&D ongoing at both RHUL and Oxford; fibre lasers are being actively developed and tested. (Funding issues beyond March 2011).
Relevant Publications • Theory/emittance extraction: • Phys. Rev. ST Accel. Beams 10, 112801 (2007) • PETRAII laser-wire: • Nucl.Instrum.Meth.A592:162-170,2008 • ATF Laser-wire: • Proc. PAC09 A. Aryshev et al. • (PRST-AB in preparation) • Possible fast scanning system based on EO: • Applied Physics Letters 94, 1 (2009)