February 12-13, 2006 FCAL Collaboration Meeting INP PAN, Kraków, Poland Readout electronics for LumiCal – first approach Wojciech Wierba Witold Daniluk Krzysztof Oliwa

February 12-13, 2006 FCAL Collaboration Meeting INP PAN, Kraków, Poland Topics Mechanical design Space for electronics Pads & strips designs Readout based on analog transmission Digital data transmission Readouts based on digital transmission

February 12-13, 2006 FCAL Collaboration Meeting INP PAN, Kraków, Poland Mechanical design of LumiCal Segmented silicon sensors interspersed into the tungsten half disks Two half barrels to allow for mounting on closed beam pipe The blue bolts support the heavy part of the detector, tungsten half disks The red bolts carry only the sensors Holes for precision survey the sensors position

February 12-13, 2006 FCAL Collaboration Meeting INP PAN, Kraków, Poland Space for electronics There is a limited space for the FE electronics for the 300 mm radius of LumiCal Bolts for tungsten & sensors support takes additional space Si sensors online positioning needs place also

February 12-13, 2006 FCAL Collaboration Meeting INP PAN, Kraków, Poland Pads & Strips Design Both designs becomes very similar Different number of electronic channels: Strips ~8000, Pads ~25000 StripsPads

February 12-13, 2006 FCAL Collaboration Meeting INP PAN, Kraków, Poland Possible readout designs Analog transmission – simple, low heat dissipation, easy to maintenance – a huge number of cables, crosstalk, noise Digital transmission – small number of digital links, no crosstalk on the transmission – complicated, high heat dissipation

February 12-13, 2006 FCAL Collaboration Meeting INP PAN, Kraków, Poland Analog transmission analog cables (coaxial or TP) needs ~30 mm round the LumiCal

February 12-13, 2006 FCAL Collaboration Meeting INP PAN, Kraków, Poland Digital Transmission LVDS link Current speed – 0.6 Gb/s Up to 10 m

February 12-13, 2006 FCAL Collaboration Meeting INP PAN, Kraków, Poland Number of LVDS links for LumiCal 5000 bunches i one train – 1 ms Break between trains – 300 ms Number of channels – bit ADC Amount of data per train – 1.25 Gb Transmission during train – 1.25 Tb/s - ~2000 links Transmission during break – 3.75 Gb/s - ~6 links >>

February 12-13, 2006 FCAL Collaboration Meeting INP PAN, Kraków, Poland Parallel conversion ADC in each channel – expensive and space on chip consuming

February 12-13, 2006 FCAL Collaboration Meeting INP PAN, Kraków, Poland Multiplexed ADC One ADC for a group of channels – cheaper, needs S/H and MUX

February 12-13, 2006 FCAL Collaboration Meeting INP PAN, Kraków, Poland Analog pipelined Analog pipeline with ~5000 cells and 10 (12) bits accuracy over 300 ms is not a easy project, but the number of ADC can be reduced by a factor of 300

February 12-13, 2006 FCAL Collaboration Meeting INP PAN, Kraków, Poland Conclusions Number of channels is essential to chose the readout solution Digital data transmitted over the break between trains Analog pipeline or MUX can reduce a number of ADC’s This talk seems to be a background for the discussion