Development of the European Scanning System Progress Report Development of the European Scanning...

Development of the European Scanning System

Progress Report

Development of the European Scanning SystemDevelopment of the European Scanning System

Cristiano Bozza – European Emulsion Group - LNF, Oct 2002

Development of the European Scanning System: progress report

The Mikrotron camera with the Photobit CMOS sensor can now work @ 87 fpsThe field of view (excluding overlapping regions) is 350 × 270 m2

We can reach a speed as large as 14 cm2/h with 16 layers sampling

Obtaining such performance is not straightforward:

Since the thread timeslice under Win2k is 10 ms, and the camera cycle time is11.4 ms, 1/3 of the fields is missed because of the software architecture(the frame grabbing is started by the host PC CPU)Actually, we only get 58 of the 87 fps...

This was expected, and we have been working on an asynchronous frame grabbing model which has now passed all technical testsAn asynchronous version of the scanning module (“VertigoScan3”) is already being debugged, and is expected to be ready for production within 2 weeks

Frame 1Frame 1 Frame 2Frame 2 Frame 3Frame 3

DAQ ThreadDAQ Thread Other Thread DAQ ThreadDAQ Thread

Frame 2 is missed because of the time structure of the present DAQ software


Old (Production version) time structure of the DAQ cycle

Image grabbing (Camera)

Image Processing (Genesis)



Clustering (PC CPU)

Tracking (PC CPU)

XY Motion

Z Motion

The command to grab each frame is issued by the PC CPUClustering must stay in sync with grabbing

CPU idle for > 50% of the time, whereas tracking may slow down DAQAvoid disk swapping (can’t use standard memory allocation)

The thread timeslice is 10 ms... Good for 60 fps (16.7 ms cycle) but not for 87 fps (11.4 ms)Frames could be missed…

Rough Z readout

Field N

Field N

Field N

Field N

Field N

Field N


New time structure of the DAQ cycle

Image grabbing (Camera)




Clustering (PC CPU)

Tracking (PC CPU)

XY Motion

Z Motion

Field N

Field N

Field N

Field N

Field N-1

Field N-1

Genesis programming for next field (PC CPU)

Trajectory data readout (PC CPU)

FlexMotion programming for next field (PC CPU)

Field N

The CPU pre-loads the commands to grab frames and to readout several Z samplesAt each field, only a “start” command is issued by the CPU

Longer time available to perform trackingDisk swapping does not cause missing frames

No problem with faster camerasVery precise Z readout

Larger memory occupancy on Genesis nodesThe core cycle needs reshaping (1 field of view delay)


A brick was exposed in Sept 2002 to test vertex location

In Salerno, we got 5 sheets + 6 CS

First task: Sheet to sheet intercalibration

Second task: CS intercalibrationwith sheet #1

Third task: CS intercalibrationwith Si-tracker

Fourth task: Scanback of possibleinteraction product tracks up tovertex

Unfortunately, thickness 30 m AGAIN!


Sheet to sheet intercalibration

4 zones 1 cm2 each were scanned on each sheet

Pattern matching was then applied from eachsheet to its nearest neighbours

For each sheet, the 3 zones with the highest matching numbers are selected out the 4 to compute the alignment parameters

This work was successfully completed for all 4 zones on all 5 sheets by using the Salerno prototype with provisional optics, no automatic light controland a CHORUS camera (Hitachi KP-F110 @ 30 fps) Scanning speed 4 cm2/h



200400 tracks match per each zoneThe resulting precision is satisfactory, and even better than needed forthe scanback phase


First task: Sheet to sheet intercalibration

Second task: CS intercalibration with sheet #1

Third task: CS intercalibration with Si-tracker

Fourth task: Scanback of possible interaction product tracks up to vertex


OK

In progress

Strategy under study...Scanback track disappearance? Multitrack crossing? Both?


Development of the European Scanning System Progress Report Development of the European Scanning...

Documents

Transcript of Development of the European Scanning System Progress Report Development of the European Scanning...