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, 2006FCAL Collaboration MeetingINP 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, 2006FCAL Collaboration MeetingINP 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, 2006FCAL Collaboration MeetingINP 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, 2006FCAL Collaboration MeetingINP PAN, Kraków, Poland

Pads & Strips Design

Both designs becomes very similar

Different number of electronic channels: Strips ~8000, Pads ~25000

Strips Pads

February 12-13, 2006FCAL Collaboration MeetingINP 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, 2006FCAL Collaboration MeetingINP PAN, Kraków, Poland

Analog transmission

25000 analog cables (coaxial or TP) needs ~30 mm round the LumiCal

February 12-13, 2006FCAL Collaboration MeetingINP PAN, Kraków, Poland

Digital Transmission LVDS link

Current speed – 0.6 Gb/s Up to 10 m

February 12-13, 2006FCAL Collaboration MeetingINP 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

>>

February 12-13, 2006FCAL Collaboration MeetingINP PAN, Kraków, Poland

Parallel conversion

•ADC in each channel – expensive and space on chip consuming

February 12-13, 2006FCAL Collaboration MeetingINP PAN, Kraków, Poland

Multiplexed ADC

• One ADC for a group of channels – cheaper, needs S/H and MUX

February 12-13, 2006FCAL Collaboration MeetingINP 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, 2006FCAL Collaboration MeetingINP 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