WFM electronics Alexandra Andersson
F. Peauger – CTF3 committee – 11/02/10 Wakefield Monitors implemented in two accelerating structures TD24 (tank version, without SiC loads (except for the WFM)) 2 WFM experiment in CLEX Each WFM will study two different modes: TM like mode at ~ 18 GHz (+ hybrid recombination) TE like mode at ~ 24 GHz RF Design finished (GdfidL + HFSS simulations) Mechanical design under progress (CERN) Connectors, Vacuum cables, 3dB/180° Hybrids ordered SiC load TM modes TE modes Waveguide bend Port signals for beam offset ∆ x=1mm 18 GHz 24 GHz TM (+ perfect hybrid) TE
F. Peauger – CTF3 committee – 11/02/10 Qualification of three firms for precise machining (2 prototypes) Results of Firm n°1: 3 Fabrication of the accelerating structures Very low roughness of turned surfaces Ra = to (spec=0.025) Roughness of milled faces higher (factor of 10) but can be improved with monocristal cutting tool Tolerances within 3 µm (spec=2.5) Planarity of 1.7 – 3.2 µm (spec=2µm), can be improved by better stress relieve process Results from Firms n°2 and 3 expected in few weeks Schedule (target): - all the disks for the two structures machined:mid structures ready for test with beam on TBTS:end 2010 ? But challenging planning Note: need maybe an additional BPM on TBTS, just before the structure (to be discussed) Very promising results
Detection scheme Waveguide Waveguide to coax Power limiter Low Noise Amplifier Down mix with 18GHz (24->6, 22.5->4.5,...) Power splitter Magnitude detected with logarithmic diode detector BandPass around 6GHz for phase detection Compare to phase of the 12GHz RF. Use Local Oscillator of common derivation
Detection Scheme
LO generation
Noise Component Loss/Gain [dB]Noise FigureGain linear Noise, F (linear) Gain casc. (linear) Noise Casc. (linear) Noise Casc. dB/Hz Gain casc. dB damped waveguide vacuum cable vacuum feedthrough Waveguide -> sma transition Waveguide and flanges Waveguide -> sma transition PIN diode limiter Low Noise Amplifier Mixer Power Splitter dBm/Hz (-174dBm/Hz + Casc. Noise Figure)mW/HzmWdBmW E-161.1E E-09
FrequencyPhase LO 1 (crystal oscillator) MHzφ1φ1 LO 2 (crystal oscillator)48 MHzφ2φ2 LO 3 (crystal oscillator)75 MHzφ3φ3 Mixer 1, LO1xLO MHzφ1+φ2φ1+φ2 Mixer 2, LO2xLO3123 MHzφ2+φ3φ2+φ3 Mixer 3, Mix1xMix MHzφ 1 +2φ 2 +φ 3 LO = Mix 3 x16 (divide-by-N PLLL) MHzφ LO= 16(φ 1 +2φ 2 +φ 3 ) 2xLO (frequency doubler) MHz2φ LO 6xLO (frequency tripler, doubler) MHz6φ LO WFM signal MHzφ WFM DownMix1 = WFM x (6xLO) MHzφ WFM -6φ LO IQ1=DownMix1x(2xLO)3.248 MHzφ WFM -8φ LO RF signal MHzφ RF DownMix2 = RF x (2xLO) MHzφ RF -2φ LO IQ2=DownMix2x(2xLO)1.624 MHzφ RF -4φ LO Phase WFM-RF = IQ1-2IQ2φ WFM -2φ RF Frequencies and phases
Waveguide
534mm 194mm
Waveguide