Sophie BaronTTC1 TTC status February 2005 ATLAS electronics

Sophie BaronTTC2 TTC news  TTC backbone General structure and main modules  TTC support  2004 structured test beam  TTC modules TTCrq TTCoc Clock generator  TTC fibres Timing stability Commissioning  TTC future

Sophie BaronTTC3 TTC global view Bunch Clock and Orbit transmission BC=40.079MHz, Orbit=11.246kHz Phase Stabilized SM fibre - 9.5km Normal SM fibre - 3.8km PCR Back to temp check

Sophie BaronTTC4 TTC partition TTC in Atlas LTP CTP L1A triggersRod Busy L1A LHC BC & ORBIT BCID, EVID, TType, calibration and test signals TTCvi TTCoc TTCrq TTCrx TTCmi TTCex TTCtx TTCvx

Sophie BaronTTC5 TTC receivers TTCrm -Agilent -TTCrx TTCrq -TRR -TTCrx -QPLL TRT-TTC -TTCrq TIM -TTCrq Agilent-2316T Truelight-TRR-1B43 Optoelectronics receivers + TTCrx + (QPLL) TTCmi/LHCrx -TTCrm -Low jitter <50ps rms -Add constraints on the BC frequency. Locking range: MHz +/- 3.7kHz Used in

Sophie BaronTTC6 TTC support  Support: Orders, production, testing and delivery of modules o Markus JOOS / PH-ESS o Web site: o Q1-2/05, production of: TTCrq 2000 pieces TTCex/tx 120 pieces Engineering and technical support o Sophie Baron / PH-ESS o Web site:

Sophie BaronTTC Structured Test Beam  June, 5-11 October  12 seconds cycles, with bunches at 25ns spacing  fixed BC and real SPS orbit transmitted by the TTC system  SPS RF frequency “resynchronized” 500ms before beam extraction to fixed MHz, 5Hz

Sophie BaronTTC8 TTC modules status - TTCrq  Activity dips problem - August- November 2004: Problem discovery: at some frequencies and temperatures the QPLL jitter was largely exceeding the typical values. With the help of Nevis, CERN and Micro Crystal worked quite hard to analyse the problem and finally confirm that it was due to activity dips in the crystal due to excessive power driving.  Activity dips are due to vibration modes that are mechanically coupled to the fundamental resonant mode. These modes can have frequencies quite close to the fundamental mode and are very dependent on temperature. They can thus interfere with the fundamental mode distorting the electrical characteristics of the crystal near the resonance.

Sophie BaronTTC9 TTC modules status  TTCrq – activity dips problem: November-December: o Once the problem analysed: Find a simple and effective way of reducing the power delivered to the crystal. o Solution validated, design and layout modified o Pre-production to be received this week R1 = 62 , R2 = 240 , C = 10 nF

Sophie BaronTTC10 TTC modules status  TTCoc TTC receiver TTC crate TTC receiver TTC receiver TTC receiver TTC receiver TTC receiver TTCex/ Single mode TTCoc/ Multi mode MultiMode Fibers MultiMode Fiber MultiMode Fibers

Sophie BaronTTC11 TTC modules status  TTCoc (cont.)  Consequences of mixing different modes: Insertion loss can not be specified: measurements shown 20dB spread between 2 outputs and could be worst Although the “standard” TTC receiver (TrueLight) works in a very wide range [-5dBm, -26dBm], some of the ATLAS sub-systems have stringent requirements on the level of light o E.g. Tile : [-15dBm,-21dBm], using the Agilent receiver  Solution proposed for ATLAS: Fibernet hybrid coupler: single-mode input and multi-mode output Same cost as initial design No need for changing existing fibres Very good uniformity  Some other solutions have been proposed for other experiments (SM2SM couplers, Mode Scramblers)

Sophie BaronTTC12 TTC modules status  New Clock generator module: MHz => compatible with QPLL ECL fanout VME form-factor Quartz MHz ordered by Per Gallno and already delivered Will be done 1Q/05

Sophie BaronTTC13 TTC fibres  Phase stability problem Clock journey Fibres are buried but the temperature is not constant o Temperature coefficient 6.8 ppm/ o C Measurements of phase shift versus external temperature made J. Troska and S. baron on a round trip PCR-PA5 i.e. 20 km

Sophie BaronTTC14 TTC fibres  Phase stability problem (cont.)  20km: 200ps typical diurnal variation  ATLAS (4km): ~50ps typical diurnal variation => Not acceptable for ATLAS => Investigation on the use of Phase Stabilised Optical Fibres (PSOF) from Prevessin to ATLAS.  20km: 1ns for 2°C average variation  ATLAS (4km): 100ps variation / 1°C 1.5ns typical seasonal variation (15°C)

Sophie BaronTTC15 TTC fibres  Atlas commissioning OTDR requested for fibres measurements Precision : 5cm : photon counting technique ( €) Wavelength 1310nm Single-mode or Multi-mode? Purchased by the pool and rented to experiments  Other needs?

Sophie BaronTTC16 TTC future  TTC crates relocation: o January 2005: PCR => AB/CO lab o December 2005: AB/CO lab => CCC o New fibres being installed now o Simulated MHz will be available in March (no machine timing) o Fibres available for ATLAS for testing purpose.  Maintenance problems: Maintenance of the TTCmi crates Maintenance of the high power lasers (PCR)  Installation: PSOF if needed Installation of the SR4 transmitters