Transcript QA for fibre bundling Dr Paul Kyberd and Dr Peter Hobson School of Engineering & Design Brunel University, UK 28 October 2004 Brunel QA for the.

QA for fibre bundling
Dr Paul Kyberd and Dr Peter Hobson
School of Engineering & Design
Brunel University, UK
28 October 2004
Brunel
QA for the Fibre Tracker
Summary
Propose 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
Virtual source
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 interplane glue.
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)
Fibre
Gap
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.)
28 October 2004
Brunel
QA for the Fibre Tracker
Simulations – collimated beam
Power crossing the midline of the
upper 4 fibres, with ~collimated
illumination.
Upper 4
Basic simulation principle
developed and it doesn’t seem to be
a priori impossible.
Light inside fibre
Lower 3
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
28 October 2004
Brunel
Using a simple
mask one fibre can
be strongly excited
(plus a few others
very weakly, here
seen in blue)
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)
28 October 2004
Brunel
4.0
QA for the Fibre Tracker
Programme of work
3
Commission final system at Brunel
Deliver working system to Imperial College
Provide 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.
28 October 2004
Brunel
QA for the Fibre Tracker