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Laser-wire at the ATF extraction line: Progress report. UK collaborators Laser-wire principle Progress on the ATF laser-wire Future plans. Nicolas Delerue, University of Oxford for the Laser Based Beam Diagnostic collaboration.
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Laser-wire at the ATF extraction line:Progress report • UK collaborators • Laser-wire principle • Progress on the ATF laser-wire • Future plans Nicolas Delerue, University of Oxford for the Laser Based Beam Diagnostic collaboration 1/8
People and institutes involvedin laser-wire activities in the UK • University of Oxford:Nicolas Delerue, Brian Foster, David Howell, Armin Reichold • Royal Holloway University London:Ilya Agapov, Grahame Blair, Gary Boorman, John Carter, Chafik Driouichi, Michael Price, Thorsten Kamps (now at BESY) • University College London:Stewart Boogert, Steve Malton We acknowledge great help from DESY, KEK and SLAC. 2/8
How does a laser-wire work? • A laser-wire uses a high power laser to shoot short laser pulses on a particle beam. • A movable mirror is used to "scan" the beam:each laser pulse is deflected by the mirror with a different angle. • When the pulse hits a bunch of electrons, Compton photons are produced. • A calorimeter is installed downstream after a bend in the electrons trajectory. • This distribution of the energy gives the beam profile. • From the beam profile, it is possible to exctract the size of the electron beam. Laser wavelength: 532 nm (Nd:YAG) Laser power: 1MW@PETRA 1GW@ATF 3/8
This year’s plans for the ATF extraction line laser-wire • March 2005:“study trip”: Understand the possible setup [optics/infrastructure], prepare our DAQ, study the laser,… • May/June 2005:Laser measurements, study the beam optics, validate the DAQ • Summer/September 2005:Install the laser transport and delivery (Optics, Scanning,…), install our vacuum vessel at the ATF and final focusing lens • November/December 2005:Laser-wire run Our latest plans for our work at the ATF are posted at: http://www-pnp.physics.ox.ac.uk/~delerue/laserwire/atf.php 4/8
Results from this trip • The APD has been validated but another detector may better suit our needs… • Some preliminary tests have been done for the DAQ. • A design is ready for the laser delivery and diagnostics optics. • Better idea of the beam jitter (thanks to the nanoBPM group). • Learned a lot about the laser and the ATF timing system (thanks to the Compton e+ group and Naito-san). • Lots of discussion on the vacuum vessel design and the lens design (still need to finalize the discussions) • Need for more work on the electron beam optics has been uncovered. 5/8
APD signal at the Compton IP • After some alignment we observed signal in the APD when inserting the screens located near the Compton IP. • Signal seen with “Y” screen but no with “X” screens (not installed). 6/8
Wire scan with the APD and our DAQ Beam profile with our system (not great yet) 7/8
Future plans • Our goal is to perform our first scan by the end of the year but… • There is still a lot of work to be done: • Electron beam optics and diagnostics • Vacuum vessel • Lens design • Laser delivery and diagnostics (scheme proposed this week) • DAQ • Put everything together • We would like to thank people from the ATF and from SLAC for their help and their support 8/8