Silicon Seminar. Optolinks and Off Detector Electronics in ATLAS Pixel Detector

Transcription

1 Silicon Seminar Optolinks and Off Detector Electronics in ATLAS Pixel Detector

2 Overview Requirements The architecture of the optical links for the ATLAS pixel detector ROD BOC Optoboard

3 Requirements of ATLAS Pixel Detector high number of channels high resolution high signal to noise ratio digital read out sensitivity during read out fast data read out

4 Advantages of optical data transmission large number of electronic channels: additional dead material (cables), problems from cross talk and ground loops optical data transmission: fast transfer rate, only small components

5 Important technical issues able to withstand high level of ionising radiation and neutron radiation should be non magnetic material must have a low mass to present a small radiation length to the produced particles

6 ATLAS Pixel Detector 3 disks Endcaps Barrel : B layer layer 1 layer 2

7 Pixel Detector consists of : B layer: 22 staves layer1: 38 staves layer2: 52 staves modules are mounted on staves

8 Pixel Modules Pixel Detector consists of 1744 moduls with about 108 pixel cells and total area of 1.7 m² each modul consists of: sensor (16.4mm x 60.4mm) 16 electronic chips (front end chips) module controller chip temperatur sensor passive components

9 Pixel Readout the pixel sensors are read out by front end electronics, controlled by the MCC. basic tasks of MCC upload configuration at startup distribution of the timing signals (40 MHz clock) and the level 1 trigger read out of the FE chips and event builder

10 The principle architecture of the optical links Optoboard Module BOC / ROD

11 Read out Driver the key element of the Off Detector electronics system interfaces to the detector mounted electronics via the BOC ( Back of Crate card ) to the TTC ( Timing/Trigger/Control ) Distribution directly via the TIM (Timing Interface Module) to LVL2 Trigger Readout Buffers (ROB) and to the RCC ( ROD Crate Controller )

12 Interface to detector mounted electronics interfaces via fiber optic clock and control links and via fiber optic data links number of detector modules per ROD B layer ROD: 7 B layer pixel modules layer 2 barrel ROD: 26 pixel modules disk ROD: 16 modules

13 Output to the Back of Crate Card ROD transmit the signals through the crate backplane each module receives configuration and control information from off detector electronics over a single optical link individual optodriver data streams for each module: more flexibility and speed in control of detector mounted electronics

14 Input from the Back of Crate Card each disk module transmits data over one 80 Mb/s FE link > the BOC converts this to two 40 Mb/s streams each B layer module transmits data over two 80 Mb/s FE links > four 40 Mb/s streams each barrel layer 2 module transmits the data over one 40 Mb/s stream

15 Input from Time Trigger Control System 40 MHz bunch crossing clock: BC Bunch crossing (BC) counter reset: BCR Level 1 accept: L1A Event (L1A) counter reset: ECR Bunch crossing count identifier (12 bits serial) Event count identifier (24 bits serial) Event type (10 bits serial) Calibration strobe

16 ROD_BUSY output each ROD must generate a ROD_BUSY signal to indicate the presence of conditions under which it cannot receiver the further data. this signal is transmited to the Timing Interface Module

17 Channel and event ordering the hit information in the output event record transmitted to the ROB must be organized by FE link. The order in which the FE links appear in the output event record must not change from event to event the ROD must transmit output event records in event order, i.e. the order in which they occurred in time

18 Read out Driver Overview

19 ROD

20 Readout Driver 2001

21 ROD

22 Back of Crate Card Regeneration of ATLAS Clock, received from TIM Send Trigger/Control signals from ROD to the detector Individual timing adjust for each detector module Clock & Data encoding (Tx PlugIn) Convertion to optical (Tx PlugIn) Regenerate data signals received from the detector Convert to electrical (Rx PlugIn) Split 80MBaud data streams to 2 x 40MBauds Adjust phase of data signals to ROD clock House the S Link interface card Uplink to readout system

23 Back of Crate Card BOC1p0 Clock Data RX Section RX PlugIn S Link Clock & Command TX PlugIn

24 Optoboard Optoboard BOC

25 B layer Optoboard

26 Opto Board provide 8 (max. 7 used) optical links two flavours: disk, layers 1 and 2: 2x4 channel DORIC and 8 channel PiN opto pack; 2x4 channel VDC and 8 channel VCSEL opto pack B layer: 2x4 channel DORIC and 8 channel PiN opto pack; 4x4 channel VDC and 2x8 channel VCSEL opto pack

27 Control data and Clock bi phased mark encoder chip (BPM) to compress the control data and the 40 MHz clock into a single stream the beam crossing clock from the ROD, BPM encoded to control the pixel detector is transmitted via a fibre to a PiN diode the BPM signal is decoded using a Digital Opto Receiver Integrated Circuit (DORIC) the clock and data signal recovered by the DORIC are in LVDS form (for the MCC chip)

28 DORIC decode the bi phase encoded clock (BPM signal) and command signals from PiN diode 40MHz clock Data BPM

29 Readout schema

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31 Optical Fibres transfers the data from the detector to the electronics in the counting room using one (B layer: two) optical fibre(s) additional optical fibre from counting room to the detector for timing information to read out a module

32 Optical Fibres radiation limiting the lifetime and the light transmission of optical fibres => * on detector side : radiation hard fibres * off detector side : radiation tolerant fibres

33 On detector PP0 (Patch Panel) and PP1 are the inner and outer ends fo the pixel detector service panels the panels carry all electrical power, sense voltages, and cooling for the detector as well as power, cooling and input/output fibres for the opto boards

34 Connection inside the pixel detector (between PP0 and PP1) is done by 8 way optical fibre ribbons outside the pixel detector (between PP1 and counting room) is done by optical fibre cables with 8 way ribbons each.

35 Pixel Detector overview Pixel detector will have 272 opto boards with 316 VCSEL and 272 PiN packages on detector each package is connected via a MT8 connector to a 8 way radiation hard optical fibre ribbon The 3 m long flat ribbons are connecting PP0 with PP1(588 ribbons) At PP1 the 588 ribbons will be connected to 78 optical cables, each connecting eight 8 way ribbon fibres

36 Fibres from PP1 to counting room not fragile 8 way ribbons but more rigid and protective optical fible cables optical cable consists of 8 8 way fibre ribbons with an outer mantle (polyurethane)

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