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11th February 201016th CTF3 Committee - Wilfrid Farabolini1 Status and progress of the CTF3 probe beam 1
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11th February 201016th CTF3 Committee - Wilfrid Farabolini22 Results of the last run (up to 14 th dec. 09) Beam charge: Immediately after photo-cathode regeneration 0.7 nC/bunch After few days 0.25 nC/bunch (QE = 0.3 %) Emittance: the problem seems solved ( normalized < 20 mm.mrad) Energy : still around 140 MeV despite higher RF compression Beam position stability: to be improved BPM calibration : to be resume during next period
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11th February 201016th CTF3 Committee - Wilfrid Farabolini33 Emittance measurements The waist is very tiny (0.1 mm) on OTR screen. Higher optical magnification used for better resolution(1.75 instead of 0.36) Simultaneous automatic scan in X and Y Use of the OTR screen is mandatory : improve yield with alumina deposition on the silicon screen. Accurate tuning of the gun coils is necessary.
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11th February 201016th CTF3 Committee - Wilfrid Farabolini44 BPM calibration 1/3 Re-entrant Cavity at CALIFE with 5 mm offset and charge = 0.6 nC Resolution : < 5 µm (simulated) with 0.1 mm offset and charge = 0.6 nC Resolution : < 0.5 µm (simulated) A complex electronic to be tuned. Up to now only the sum signals demodulated on a diode were used Problem with phase stability of the reference signal and/or position stability of the beam
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11th February 201016th CTF3 Committee - Wilfrid Farabolini55 BPM calibration 2/3 Beam charge calibration is OK (obtained by varying laser power) Beam position when delta signal is demodulated with a diode is fine.. But more problematic when send to the dedicated electronics (obtained with corrector scan) Demodulated I/Q signal Computed beam position as function of time With diodes With I/Q demodulator
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11th February 201016th CTF3 Committee - Wilfrid Farabolini66 BPM calibration 3/3 Tuning of the electronics to be resume during next run (choice of reference frequency signal, attenuator settings…) Possibly a real problem with beam position stability (I/Q have a much better resolution that diodes) Laser position stability (transport line mirrors and lens to be investigated) HV pulse from modulator MKS 30 known to have ripple (tuning to be resume)
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11th February 201016th CTF3 Committee - Wilfrid Farabolini77 THE POWER PHASE SHIFTER IS INSTALLED On place in the CLEX gallery 28/jan/2010 phase/position relation (1 deg / mm) Phase S12 (deg) Déplacement (mm) S22 (dB) Reflected power vs. frequency for various positions Compression Accélération 180 MeV
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11th February 201016th CTF3 Committee - Wilfrid Farabolini88 How does it work ? Fixed Fixed Movable Guided wavelength depends on the transverse waveguide size Cylindrical WG TE 01 no electric field on the walls ! TE 10 □ TE 01 ○ E Field Rectangular to circular mode convertor
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11th February 201016th CTF3 Committee - Wilfrid Farabolini9 On going works Development of 2 new MTVs (Califes like) for the TBTS lines with Uppsala University To be installed before 15 th march Development of a user friendly interface for Califes on the same model as for TBTS in Labview by the EN/ICE group RF phase and power coupler calibration on the accelerating structures
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11th February 201016th CTF3 Committee - Wilfrid Farabolini10 Conclusions We are ready to resume operations with better diagnostics and to experience the phase shifter. Probe Beam should now be experienced in the ACS.
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