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QA for fibre bundling. Dr Paul Kyberd and Dr Peter Hobson School of Engineering & Design Brunel University, UK. Summary. Propose a non-destructive method to check that the fibres have been correctly bundled into groups of 7. - PowerPoint PPT Presentation
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28 October 2004 Brunel QA for the Fibre Tracker
QA for fibre bundling
Dr Paul Kyberd and Dr Peter HobsonSchool of Engineering & DesignBrunel University, UK
28 October 2004 Brunel QA for the Fibre Tracker
SummaryPropose a non-destructive method to check that the fibres have been correctly bundled into groups of 7.
To assist with QA of fibres once in connectors (breaks, relative light yield)
To design, construct, deliver and maintain a precision optical assembly, 400 mm travel precision stage and associated computer control system for QA laboratory.
28 October 2004 Brunel QA for the Fibre Tracker
Overall system concept
Precision illumination to excite only the bundle of 7 fibres OR
System to illuminate two bundles of 7 either side of the desired “dark” bundle– Fits better with the symmetry of the problem
– May be easier to arrange
– Step through all the groups of 7 to aid in assembly of fibres into ferrules.
Can use the same system afterwards to check that there are no significant breaks in the fibres.
Use a video camera to aid in the original alignment of the illuminator with respect to a datum on the plane.
28 October 2004 Brunel QA for the Fibre Tracker
Scanning Light source
Excite the 3HF fluorescence with light around 390 nm.
Use low average power to preserve fibre secondary fluorescence (pulse the light source?).
Excite group of 7 fibres (3+4 in the two planes) then step on to next 7 etc.
Still at the concept stage, but simulations underway, and experimental tests on fibres now underway (October 2004).
28 October 2004 Brunel QA for the Fibre Tracker
Simulations – convergent beam
True 3D simulation (non-sequential).
Includes ray splitting, polarisation, scatter and absorption effects.
Horizontal lines through fibres on this view are “detector” planes to measure the energy passing through the mid-planes of the fibres.
Cuboid volume represents the inter-plane glue.
Virtual source
28 October 2004 Brunel QA for the Fibre Tracker
Simulations – convergent beam
Power crossing the midline of the upper 4 fibres. Energy in gaps doesn’t excite these fibres (but does excite the 3 fibres in the bottom row)
A lot of optimising to do to get the best discrimination for the lower row and to understand what sort of illumination would be best (e.g. narrower but more collimated etc.)
Fibre
Gap
28 October 2004 Brunel QA for the Fibre Tracker
Simulations – collimated beam
Power crossing the midline of the upper 4 fibres, with ~collimated illumination.
Basic simulation principle developed and it doesn’t seem to be a priori impossible.
Upper 4
Lower 3 Light inside fibre
28 October 2004 Brunel QA for the Fibre Tracker
Programme of work 1
Test basic principle in Brunel laser laboratory with non-critical lengths of fibre.
Check fibres for any induced change of properties.
28 October 2004 Brunel QA for the Fibre Tracker
Recent “proof-of-principle”
This October we have made some rather simple tests to see if this technique is viable.
We have evaluated a number of violet and near-UV LED sources.– Violet (peak emission around 400 nm) are not
useful.
– Near-UV (around 370 nm) can excite green fluorescence strongly.
28 October 2004 Brunel QA for the Fibre Tracker
Fibre plane tests
Imperial College have recently lent us an old fibre plane for tests.
We have demonstrated that one can excite single fibres, or groups reasonably easily.
Green fluorescence is easily seen even with fairly low levels of excitation light.
28 October 2004 Brunel QA for the Fibre Tracker
Glows in the dark
Many fibres illuminated at once. Red background is from the laboratory “safe” light
Using a simple mask one fibre can be strongly excited (plus a few others very weakly, here seen in blue)
28 October 2004 Brunel QA for the Fibre Tracker
Programme of work 2
Design optical illumination system and prototype
Purchase 400 mm travel precision stage – absolute accuracy ~ 10 µm– precision ~ 1 µm
Design and implement LabView DAQ system.
28 October 2004 Brunel QA for the Fibre Tracker
Stage specification
Travel Range (mm) 400
Resolution (µm) 0.1
Minimum Incremental Motion (µm) 0.1
Bi-directional Repeatability (µm) 0.2 typical
Absolute Accuracy ±1.25 µm per 100 mm, typical
Speed Range 0.01 µm/s to 100 mm/s
Speed Regulation ±1% RMS typical above 10 µm/s
Acceleration Range (g) 0.001–0.25
Normal Load Capacity (N) 680
Straightness/Flatness (over center 80% travel) (µm) 4.0
28 October 2004 Brunel QA for the Fibre Tracker
Programme of work 3
Commission final system at BrunelDeliver working system to Imperial CollegeProvide calibration, documentation,
support, maintenance and repair during the fibre-plane assembly phase of the project.
28 October 2004 Brunel QA for the Fibre Tracker
Resources
Dedicated technician support for construction, commissioning and maintenance (~ 0.5 FTE per year for two years)
Precision stage and control computer– On loan to MICE UK– No cost to MICE UK
Specific equipment, e.g. light source, optics etc. are a small call on the MICE UK equipment budget.
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