louis nicolas – lphe-epfl it from a to z march 6th, 2006 the lhcb inner tracker production: from a...

Louis Nicolas – LPHE-EPFL IT from A to Z March 6th, 2006

The LHCb Inner Tracker Production:

From A to Z

Louis Nicolas

LPHE – IPEP – SB – EPFL

Monday Morning SeminarMarch 6th, 2006

LPHE-EPFL, Lausanne


The Inner Tracker in the LHCb Experiment (1/2)

- The Inner Tracker (IT) is part of the Silicon Tracker (ST) as well as the Trigger Tracker (TT).- Silicon micro-strips detector covering a cross-shaped area around the beam pipe in each of the stations.- IT is formed by 3 stations (T1 – T3), each made of 4 boxes containing 28 modules.- Each module contains one or two silicon sensor with 128 strips each.- It is aimed at tracking particles in a region with really high particle flux.

TT

IT: T1-T3

2/24


The Inner Tracker in the LHCb Experiment (2/2)

Recent pictures taken in the LHCb cavern:

Space forthe IT

3/24


Construction and Production of the Inner Tracker

The Inner Tracker is being built at this moment by several groups around the world:

Lausanne, CH --> IT modules, cooling rods, frames, bonding and testingZurich, CH --> Digitizer boards, Service boxes, sensor testing, data cablesRHe, D --> HybridsHeidelberg, D --> Hybrids (with beetles + pitch adapters)Hamamatsu, JP --> SensorsSantiago, ES --> Bonding, IT boxes, control card and testing

4/24


Lausanne Lab for the IT: Production and Tests (1/5)

If you worked in the Lausanne lab, youcould look like this:

Steps of the production performed in Lausanne:

Production of the IT modules (from skin testing to sensor gluing)

Construction of the IT frames

Construction of the cooling rods

Cooling tests

Material Budget and XML modelling

Writing of the voltage test code for the CERN lab burn-in stand

5/24



IT modules production: some of the steps performed in Lausanne:

1) Raw ladder:

2) Ladder with glued hybrid:

3) Ladder with glued hybrid and sensor:

Balcony (heat transfer)

Pitch Adapter Beetles

6/24



7/24

4 IT boxes (one station)

Space for beam pipe

Readout cables

Cooling pipes

To service boxes

This is the IT support frame as it will look in thereal experiment (only with real boxes and slightlydifferent cables):



8/24

The cooling rods have been built in Lausanne. Some tests are being performed to check that it’s notleaking and that the cooling power of C6F14 is sufficient enough to cool down the sensors heating up inthe experiment.

A chair!

Test supportframe

Cooling Rodswith connectors

Cooling Rods

IT Box

Dummy ladders withtemperature sensors



9/24

An XML model of the IT has been implemented and we now have a realistic view of the materialthat composes the IT.

Amount of material traversed by particles going through the Inner Tracker:

IT Boxes Data Cables


CERN Lab for the IT: Bonding and Testing (1/2)Bonds are used between the beetles and the hybrid, between the hybrid and the pitch adapter andbetween the pitch adapter and the sensor.Some pictures of the bonds on the hybrids: 50 m wires sealed using ultrasonic power

10/24


CERN Lab for the IT: Bonding and Testing (2/2)

11/24

Ageing test:

6 modules at a time in a temperature cycling box.

-10 to 30°C (we could go up to 60°C).

Voltage test at different stages during the temperature cycle.

Electronics used is (almost) the same as in the real experiment.

Several run are possible to test the modules.

Modules built Modules bonded Modules complete

Accelerated ageing test:- Temperature Cycle- Voltage Test


The Electronics Related to the IT (1/3)

TELL1 Board, by G. Haefli, EPFL: Off-detector electronics acquisition readout board for LHCb readout of optical or analog data from the front end electronics.FPGA based board for event synchronisation, buffering during the trigger latency, pre-processing including common mode correction and zero suppression.For data acquisition, interfacing to standard Gigabit Ethernet network equipment providing up to four GBE links.Two different link systems (analog and optical) -> receiver part implemented as mezzanine with either digitizer or de-serializer.Common interface on the receiver side -> same board for all sub-detectors.For ST: provide connectivity for 24 optical links de-serialized running at 1.6 GHz carrying the information of 24 x 128 strips sampled with 8-bit in total. The data is transferred on multiplexed 16-bit wide data buses running at 80 MHz. In addition at least the receiver clock, the data valid and the error control signals must be connected.

12/24



ODIN Readout Supervisor, by R. Jacobsson, CERN: Distribute the LHC clock to the entire FE electronics and the trigger systems.Distribute the L0 trigger decision to the L0 FE electronics.Distribute the L1 trigger decision to the L1 FE electronics (Not in the newest versions).Generate and time-in all types of self-triggers (random triggers, calibrations, etc.).Control the trigger rate by taking into account the status of the different components in the system in order to prevent buffer overflows and to enable/disable the triggers at appropriate times during resets, etc.Generate and time-in resets (counters- and electronics-) and the other asynchronous commands.Record detector status information and information related to timing, triggering and fast control in a special data block and transmit them to the event buildingIncorporate an ECS interface for configuring, controlling and monitoring the Readout Supervisor

13/24



14/24

Digitizer Board, by A. Vollhardt, Zurich:

Control Board, by D. Esperante, Santiago:

Analog In Digital Out

Communication to the beetlesvia the back plane and the Dig. board

To the computer:SPECS master

Gets analog signal from the beetles (via coppercables), digitizes it and sends it to the TELL1via optical fibres.Gets commands from the Control board via theback plane and sends them to the beetles via thecopper cables.

Gets commands from the SPECS master(computer) and sends them to the beetles via theback plane, digitizer boards and copper cables.Gets commands from the Readout Supervisorand sends them to the beetles (like calibrations).


The IT Burn-in Stand (1/3)

This setup uses (almost) the same electronics as inthe real experiment:

TELL1 Board (left)

Readout Supervisor (right)

Service Box containingControl Card (left slot)Digitizer Boards (other slots)

IT Modules

Optical Fibres

5m Copper Cables

For this burn-in test, we also use:

Temperature Cycling Box

15/24



About 1 minute to take dataUp to 6 modules at a time (limited by size of the temp. cycling box)

Temp Cycling

daq.exe

ControlCard

ReadoutSupervisor

Dig Board

Tell1

TempCycling

Box

Beetles

LabView (Windows) LabView (Linux)

Parallel

Port

TCP

SPECS

DAQ

DIM

sudo DAQ

GBE link

16/24



17/24

List of the protocols / format / links used to send informations:

TCP: Transmission Control Protocol. TCP is one of the core protocols of the Internet protocol suite. Using TCP,applications on networked hosts can create connections to one another, over which they can exchange data orpackets.

SPECS: Serial Protocol for the Experiment Control System of LHCb. The SPECS is a 10 Mbit/s serial bus, designed to besimple, cheap, reliable and to work in radiation sensitive environments. It is mainly used to download and readback the configuration of the electronics located on the detector. It provides I2C and JTAG interfaces for the users.

I2C: Inter Components Communication, Inter Integrated Circuits. Simple bi-directional 2-wire bus for efficientInter-Integrated Circuit Control.

JTAG: Joint Test Action Group. JTAG is the usual name used for the Standard Test Access Port and Boundary-ScanArchitecture for test access ports used for testing printed circuit boards using boundary scan.

DIM: Distributed Information Management System. DIM is a communication system for distributed / mixed environments.It provides a network transparent inter-process communication layer.

GBE: GigaBit Ethernet. Technologies for implementing Ethernet networking at a nominal speed of one gigabit per second.Ethernet is a frame-based computer networking technology for local area networks (LANs).


The Voltage Test Code in More Details (1/4)

18/24

Main goal: provide a code to analyse the behaviour of the beetles and test the readout strips.

Old code exists but uses an obsolete version of the electronics boards (RB2, SEQSI) and isvery slow (1 h / 1 module --> 1 min / 6 modules).

Challenge: Communicate with the new boards (TELL1, Readout Supervisor and ControlCard) to perform the wanted scans and get the data in a Root tree for further analyses.

Several C/C++ codes have been written to:Initialize / Stop the electronicsRun delay and/or pipeline scanDebug the whole setup



19/24

Run: The two different scans can be run individually or in a row:

Delay Scan:Short delay scan without saving data in order to find proper timing (peak)PedestalDelay scan, saving data (to allow further investigation on the pulse shape)Channel scan (one every 8 channels on, with offset from 0 to 7)

Pipeline Scan:Short delay scan without saving data in order to find proper timing (peak)Pipeline scan (from 1 to 187 = beetle pipeline length)

Delay Scan:

We delay the test pulse w.r.t. the trigger tosample each time at a different point on thetest pulse and get a general view of the testpulse shape.

Pipeline Scan:

The beetles have a pipeline to store the signalwith a length of 187 spaces. We change theoffset (number of bunches in the orbit beforethe trigger calibration is sent) to get each timethe data from another pipeline column.



20/24

The temperature cycle in more details:

1 Cycle (-10o,0o,10o,20o,30o,20o,10o,0o,-10o) lasts ~2h

At each temperature, the box is stabilized and the DAQ code is ran:

Data acquisition ~1.5 min:

Pedestal: 4k events

Delay Scan: 0.5k events * 2 masks * 21 delays

Channel Scan: 0.5k events * 9 masks

Pipeline Scan: 0.2k events * 187 PCN

How to get data from the beetles to the computer:Computer sends command to the Readout SupervisorReadout Supervisor sends a calibration test pulse to the beetlesBeetles send the analog signal back to the digitizer boardDigitizer board passes digital signal to the Tell1Readout Supervisor sends a trigger to the Tell1Tell1 passes packets of data to the computer via GBE linkComputer analyses the stream of data and saves it in a root file

Reliability mechanisms have been implemented in case of RS or TELL1 failure: multi-threaded and temporized data readout. No packet is lost and the program exits in case of a time out due to a link error (RS spurious resets have been the most typical issue) (19 errors)



21/24

[Program Settings]Configuration File Name = ConfigValues.txtPerform Delay Scan? yesPerform Pipeline Scan? noDIM DNS Node = "pcepfl01" Time Out Duration = 10 seconds

[Program Settings / Delay Scan Settings]Delay Scan Number of Events = 256Delay Scan Number of Pedestal Events = 2048Delay Scan File 1 Name = Del_Module1Delay Scan File 2 Name = Del_Module2Delay Scan File 3 Name = Del_Module3Delay Scan File 4 Name = Del_Module4Delay Scan File 5 Name = Del_Module5Delay Scan File 6 Name = Del_Module6Delay Scan File 7 Name = Del_Module7Delay Scan File 8 Name = Del_Module8Estimated Peak Position = 75

and the same for the Pipeline Scan Settings

[Temperature Cycling Box]Number of Modules = 8Test Module 1? yesTest Module 2? noTest Module 3? yesTest Module 4? yesTest Module 5? yesTest Module 6? noTest Module 7? yesTest Module 8? yes

[Beetle Parameters]Test Pulse Bias Current = 0x60Pre-Amplifier Bias Current = 0x4CShaper Bias Current = 0x0A Front-End Buffer Bias Current = 0x0APre-Amplifier Feedback Voltage = 0x05Shaper Feedback Voltage = 0x00Comparator Bias Current = 0x05Comparator RC Time Constant = 0x00Output Buffer Bias Current = 0x99Trigger Latency = 0x60

etc...

To give the user an easy way to control the run and the data, a configuration file has been implemented.Below are written some of the parameters that the user can set in this configuration file:


Analysis (1/2)

22/24

© J. v. Hunen & H. Voss

Once the scans have been performed, we need to analysis the data.Unfortunately, the new setup hasn’t been used yet. We only have plots for the old setup.Plots of the Delay Scan andthe Temperature Cycling


Analysis (2/2)

23/24

© J. v. Hunen & H. Voss

One of the goals of the setup is to show if there are shorted or broken channels.This can be seen on a noise spectrum as shown below:


Conclusion

24/24

Peter and Marc-Olivier are producing the modules (almost) at full speed.

The frames will be built by the Lausanne workshop on time to install them before the beam pipe.

Aurélie and Marc-Olivier are finishing the cooling tests (last series of measurements).

Kim and Aurélie are finishing the material budget and XML modelling (waiting for someinformation about the data cables after several changes already).

The bonding at CERN has started again after a long break due to some material problems.

The IT burn-in stand should start soon testing modules with the new setup, hence much faster(Daniel and I are waiting on Helge to analyse the first data we’ve produced to finish improvingthe code and maybe add a few more features).

--------> Let’s be optimistic: Everything looks great!!!


In case it was not clear enough...

Please refer to this book:

louis nicolas – lphe-epfl it from a to z march 6th, 2006 the lhcb inner tracker production: from a...

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