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Readout electronics for LumiCal – first approach. Wojciech Wierba Witold Daniluk Krzysztof Oliwa. Topics. Mechanical design Space for electronics Pads & strips designs Readout based on analog transmission Digital data transmission Readouts based on digital transmission.
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Readout electronics for LumiCal – first approach Wojciech Wierba Witold Daniluk Krzysztof Oliwa 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 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 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 FCAL Collaboration Meeting INP PAN, Kraków, Poland
Pads & Strips Design Strips Pads • Both designs becomes very similar • Different number of electronic channels: Strips ~8000, Pads ~25000 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 FCAL Collaboration Meeting INP PAN, Kraków, Poland
Analog transmission • 25000 analog cables (coaxial or TP) needs ~30 mm round the LumiCal FCAL Collaboration Meeting INP PAN, Kraków, Poland
Digital Transmission LVDS link • Current speed – 0.6 Gb/s • Up to 10 m 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 – 25000 • 10 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 >> FCAL Collaboration Meeting INP PAN, Kraków, Poland
Parallel conversion • ADC in each channel – expensive and space on chip consuming FCAL Collaboration Meeting INP PAN, Kraków, Poland
Multiplexed ADC • One ADC for a group of channels – cheaper, needs S/H and MUX 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 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 FCAL Collaboration Meeting INP PAN, Kraków, Poland