TTC system for FP420 reference timing? TTC = Timing Trigger Control Sophie Baron (PH-ESS) Sophie BARON, PH-ESS FP420 Collaboration meeting, Sept. 2006

FP420 requirements for timing transmission Bunch Clock and Orbit(?) to be transmitted Level of radiations = ?? Clock monitoring between the 2 signals 10 ps rms jitter skew between the clocks in W and E Sophie BARON, PH-ESS FP420 Collaboration meeting, Sept. 2006

FP420 Collaboration meeting, Sept. 2006 Existing system The TTC system Rad-hard chips Monitoring the phase between 2 optical signals Various transmission schemes used by the TTC system Typical jitter values Sophie BARON, PH-ESS FP420 Collaboration meeting, Sept. 2006

FP420 Collaboration meeting, Sept. 2006 TTC system in one slide Transmission of… Timing of the LHC from the RF source to the experiments LHC Bunch Clock (40.078xx MHz) Revolution Frequency (11.245x kHz) Then combined inside the experiments with … Trigger and Control signals Used by front-end electronics and readout systems …Using single optical fibres… …and a lot of various components and modules… Sophie BARON, PH-ESS FP420 Collaboration meeting, Sept. 2006

Radiation hard components TTCrx: 50ps rms The TTCrx is now fabricated in the radiation-hard DMILL technology, which completely eliminates the possibility of a single- event latch-up, and should show a high immunity to single-event upset (SEU). Tested up to : 8 Mrad (X-Rays) and – 5 x1013 n/cm2 (Neutrons) QPLL: 10-15ps rms Tested up to 10Mrad (Co-60 γ) + 3 1015 n/cm2 TRR receiver: Optical receiver from Truelight (Taiwan) selected for most of the TTC designs Tested with the TTCrx at the same doses. OK if the optical power level stays above -20dBm (0.1mW) Optical Fibers: sensitive to radiations (attenuation increases with the dose) Special fibres validated for ATLAS and CMS at high radiation levels (1014-1015 n cm-2 and total dose of 100 to 300 kGy) Radiation hardness of multi-mode optical fibres for the ATLAS detector readout (June 1999,DG Charlton et all) Sophie BARON, PH-ESS FP420 Collaboration meeting, Sept. 2006

Clock differences Monitoring? Comparator control Phase shift with temperature: Typical value: shift of 25ps/degC/km FP420 => 12ps/C per side if 420m on each side Limit of the measurement: The jitter between the W and E zones can not be monitored, as it is manly generated by the electronics doing the optical to electrical conversion The measurement will only concern the phase shift between the 2 segments Sophie BARON, PH-ESS FP420 Collaboration meeting, Sept. 2006

FP420 Collaboration meeting, Sept. 2006 Transmission Schemes Encoded TTC inside the experiments (based on aTTCrx chip) Advantage: Allows to encode the orbit signal (and control frames) to the 40.078MHz Drawback: jitter increases with the quantities of encoded data QPLL added to reduce the jitter of the recovered clock down to 10-15ps rms Parallel TTC backbone system Orbit and clock on separate fibres Advantage: very low jitter after the opto-electrical conversion (10ps) without using the QPLL Sophie BARON, PH-ESS FP420 Collaboration meeting, Sept. 2006

FP420 Collaboration meeting, Sept. 2006 Encoded Scheme [1] Used to transmit Timing, Trigger and Control inside the experiments Serial transmission 2 Channels are transmitted A Channel: Broadcasting Orbit (or L1a in experiments) Low latency Time critical signals B Channel: Framed & formatted commands and data (Hamming) Broadcast or individually addressed Internally used in the experiments A & B are Time Division Multiplexed BiPhase Mark encoding is used at 160.316Mbaud: balanced signal B* A TDM Encoder 40MHz Clock A B A B A B A B A B + BPM 1 A Orbit B* (Idle) 25ns Sophie BARON, PH-ESS FP420 Collaboration meeting, Sept. 2006

CH. A (pulse, Orbit or trigger) CH. B (serial data frame) Encoded Scheme [2] Encoder & laser tx Photodiode, decoder & clock recovery Encoded Clock, A, B TTCrq TTCrx TRR QPLL Decoded CH. B Recovered Clock 50ps rms cy2cy Decoded CH. A CH. A (pulse, Orbit or trigger) CH. B (serial data frame) 40MHz Clock TTCex 15ps rms cy2cy Sophie BARON, PH-ESS FP420 Collaboration meeting, Sept. 2006

FP420 Collaboration meeting, Sept. 2006 Parallel Scheme Clock and orbit on parallel fibres RF signal transmission scheme Picture RF_Tx_D Picture RF_Rx_D Tx Board Rx Board Laser Types OCP03: 300 $ OCP Tx 24: 600 $ Photodiode Types OCP Rx 03: 230 $ OCP Rx 24: 300 $ TRR: 8 CHF! Sophie BARON, PH-ESS FP420 Collaboration meeting, Sept. 2006

Typical Jitter values – Parallel Scheme [1] OCP Tx 03 Comparator control C2 C3 TRR-1B43 + fanout +ECL driver TRR-1B43 + fanout +ECL driver C1/C2 12.4ps C1/C3 12.4ps C2/C3 6.5ps Lecroy Wavepro 7100 1GHz Sophie BARON, PH-ESS FP420 Collaboration meeting, Sept. 2006

Typical Jitter values – Parallel Scheme [2] OCP Tx 03 Comparator control C3 C2 OCP Rx 03 + fanout +ECL driver OCP Rx 03 + fanout +ECL driver C1/C2 11.5ps C1/C3 11.4ps C2/C3 4.0ps Lecroy Wavepro 7100 1GHz Sophie BARON, PH-ESS FP420 Collaboration meeting, Sept. 2006