Peter Göttlicher, DESY-FEB, XFEL-DAQ-2007/03/051

XFEL-PIXELReadout and control

Detector requirements/proposal

Basic concepts for experiments

Control electronics

Selecting/rejecting bunches

Backend-systems

Time schedule

Conclusion

Peter Göttlicher, DESY-FEB, XFEL-DAQ-2007/03/052

Detector requirements

Call for experiments:

large pixel detectors: > 1Mega-Pixel

large number of frames: XFEL: 30000 bunches/sec

large dynamic range 104-106 Photons/pixel/frame

distinguish 0 and 1 Photon, rest Poisson-limit

With 2Bytes/pixel and 1MPixel 60GByte/sec

- but experiments will not handle frame rate

- Data reduction of "compression" is not effective:

Statements of nearly nothing to factor 2-4.

Peter Göttlicher, DESY-FEB, XFEL-DAQ-2007/03/053

Three ProposalsAP-HPAD: analogue pipe-line Hybrid Array Pixel Detector

Si-pixel: ASIC stores signal while bunch train into capacitorsdigitization/data-transfer in pause between trains

400 frames/train

LSDD: Linear silicon drift detectorOne dimension is coded into drift-time: 200MS/s while traindata transfer in pause between trains.

600 frames/train

LPD: Large Pixel Detector analogue pipeline while train digitization between trains512 (256) frames/train

All extendable beyond 1Mpixel All around every 5-10 bunch All might run in parallel

Peter Göttlicher, DESY-FEB, XFEL-DAQ-2007/03/054

Idea: Basic setup of all experiments

Specific to experiment, here AP_HPAD

Generic for all experiments

Peter Göttlicher, DESY-FEB, XFEL-DAQ-2007/03/055

Idea: Concept for control electronicsGeneral task:- Boot- Collect information- Synchronize to XFEL clocks, time- Synchronize Interface electronics Backend Experimental area- Generate/distribute Clocks/data- User interface- Write to backend Monitoring/Status- Usage at other laboratories

Peter Göttlicher, DESY-FEB, XFEL-DAQ-2007/03/056

Selecting/rejecting bunches

Aim: - Best use of limited pipeline in detector-head- Limit resources for backendStaged concept:- Store predefined bunches into pipeline of experiment- Fast reject (before next bunch): hardware detector,....- Slow reject: After bunch train

Handle slower information, information from XFEL- Transfer to backend-system

More fancy selection in CPU-farmRates: hard to guess, input from science needed- gas stream through X-ray-beam: - solid targets in beam (just first bunch)- that is not all. Who needs what?/how much?

Peter Göttlicher, DESY-FEB, XFEL-DAQ-2007/03/057

Idea: Data stream to and concept of backend-system

Aim:- Collect complete frames into one CPU- Data in mass storage sorted for "Offline"-analysis

Allowance:

- Calculation on frames before sending to mass storage

- Decisions on frame to store/reject inside backend system.

- Rejecting frames on more fancy information from external signals.

- Write data frame-wise to mass storage - easier offline.

Peter Göttlicher, DESY-FEB, XFEL-DAQ-2007/03/058

Interface: Experiments to backend-system

Rough:Data from Pixels written toRAM and read in other sequence

By that:One group of frames transfers to 1 Link to BE.

Still 8 or more of such modules transfer tosame backend-system

Peter Göttlicher, DESY-FEB, XFEL-DAQ-2007/03/059

Need, controlled time sequence:So that each CPU gets data from all interface-modules without time conflict

Peter Göttlicher, DESY-FEB, XFEL-DAQ-2007/03/0510

Idea: Concept of backend-system

Switch CPU-Farm

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massstorage

controlelectronics

Feedback

monitoringdata

XFEL-accel.?

Peter Göttlicher, DESY-FEB, XFEL-DAQ-2007/03/0511

Rates:

- Not well defined, what does which of experiment

- AP-HPAD: 2Bytes/pixel/frame is reasonable

- LSDD: Start with over sampling: Where to reduce to what, has to be a common diccussion- LPD: Rate expected to be similar to AP-HPAD, but I haven't seen their proposal.- First tests of compressions had been not effective Recent statement for single case was factor 2-4.Estimate to storage: 1Mpixel * 500bunches/train * 2Bytes/pixel * 10trains/s 10GBytes/secDiscussion with inputs from backend/science needed to settle rates/uptime/technical-effort/offline-effort

Peter Göttlicher, DESY-FEB, XFEL-DAQ-2007/03/0512

Time schedule

2007: Experiments write proposal 15-April 2007

end 2007-2013: Designing, Constructing, but also

Laboratory tests and usage at other beam lines

2009(?) DAQ needed for tests - no large CPU-farm

LCLS has 120Hz and not 30000bunches/sec

2013: 1Mpixel dedectors at XFEL 3*(10-20GB)/sec

20xx: Upgrades beyond 1MPixel (e.g. 4Mpixel)

Peter Göttlicher, DESY-FEB, XFEL-DAQ-2007/03/0513

Conclusion

Concept is there, open to change and do an other wayTwo aspects: Control electronics

Backend-system

Ideas about numbers, but a lot of open questions

Discussions needed with input for - effort in backend- science requirements- offline possibilities- feasibility of interface-electronics

Common effort for all experiments is a strong wish