1. Takashi Matsushita t.matsushita@imperial.ac.uk Imperial College T. Matsushita 1 Quality Control of Station Assembly

2. T. Matsushita 2 Stations built so far Prototype stations 1 – 4; had problems: Did not know which channel is the centre of the station Lots of problems on channel mapping Light loss due to hole mis-alignment at optical connectors Fifth station – the first production version for trackers Built with new procedure that incorporates quality control to rectify any errors occurred during manufacturing. Improvements: Centre fibre clearly marked during ribbon production Optical connector hole alignment checked Number of bundles in a connector checked Number of fibres in a bundle checked Sequence of fibres checked Should have rectified problems encountered for stations 1 – 4, yet to be confirmed

3. T. Matsushita 3 Station assembly overview First doublet-layers are manufactured at FNAL 350  m diameter fibres are laid-out on a mold with groove pitch of 426  m; 1491 fibres used per doublet-layer Then make bundles of seven fibres, put them through optical connectors, then layers stacked and glued Quality Control before gluing them together Centre fibre

4. T. Matsushita 4 Bundling - i Make bundle of seven fibres starting from the centre fibre Seven fibres held together with rubber tube => single read-out channel “comb” is used for bundling and QC procedure; bundles are stacked in grooves of the comb, channel map defined bundles of four columns (5-6-5-6 or 5-6-5-4) for one connector

5. T. Matsushita 5 Bundling - ii

6. T. Matsushita 6 Connectorisation - i A 22 way optical connector mates seven scintillating fibres with one clear fibre waveguide; alignment of connector holes at scintillating fibres and clear fibres sides are checked with ‘go/no-go gauge’ The scintillating fibre bundles are threaded through one of 22 holes of optical connector Connectorisation mapping for view X

7. T. Matsushita 7 Connectorisation - ii “Bridge” a tool for QC Fibre radius guide is used for connectorisation Bridge with connectors in place

8. T. Matsushita 8 QC - setup Bundling/Connectorisation most labour intensive, source of errors We perform QC step after bundling/connectorisation with the setup shown Translation stage LED (20 mW, = 405nm) / optics Doublet layer CCD

9. T. Matsushita 9 QC– counting - i First number of bundles for a connector as well as number of fibres in a bundle are checked after bundling and connectorisation CCD images of one connector worth of bundles are taken Fibre bundles in comb Fibre bundles in connector

10. T. Matsushita 10 QC – counting - ii Then software identifies bundles and fibres in the CCD image taken Notifies operator if there are any failures Twenty two bundles identified for comb/connector Seven fibres in a bundle identified with different colours Analysed comb imageAnalysed connector image

11. T. Matsushita 11 QC – scanning - i If counting QC was OK, move on to fibre sequence check by LED scanning Scan fibre plane with UV LED at 1250 micron/seconds Capture image at 24.98 frames/seconds => 50 micron/frame [movie] Trace sum of CCD intensity for 9 pixels around fibre centre Bottom fibre signal distorted by the top fibres and glue Top fibres Bottom fibres UV LED

12. T. Matsushita 12 QC – scanning - ii Find frame # of intensity “peak” of each fibre; Frame # of leading edge = maximum intensity * 0.5 Frame # of trailing edge = maximum intensity * 0.5 Frame # of ‘peak’ = (leading edge + trailing edge)*0.5 Plot frame # of intensity ‘peak’ of each fibre; As frame # increases bundle # (channel number) increases, no overlaps of X Fibre sequence as well as bundle order should be OK before gluing a ribbon Max. “peak” Each X corresponds to ‘peak’ Seven X in each bundle

13. T. Matsushita 13 QC – scanning - iii Samples of errors identified during assembly Fibre swap between bundles 17&18 and 19&20 Wrong bundle order

14. T. Matsushita 14 QC – scanning - iv Time interval of each ‘peak’ checked as well Negative interval if there is fibre swap between bundles mean = 4.24 frames => 212.17 micron agrees with measured mold pitch of 426/2 micron

15. T. Matsushita 15 Point of no return - gluing Fix vacuum chuck, carbon-fibre station frame to gluing jig Then glue them together

16. T. Matsushita 16 Potting & polishing Pot fibres to connectors, then apply glue to stiffen fibres then cut and polish Apply glueCut fibres After polishing

17. T. Matsushita 17 Summary New station assembly procedure with QC process incorporated worked out to overcome problems seen in prototype stations Station 5 built with new manufacturing procedure, which proven to work 4473 350 micron fibres successfully bundled and connectorised by hand Ready for test with read-out Station assembly is underway with the new assembly procedure