Tracker Mechanical Progress

1
Tracker Mechanical Progress

• Contents-
• Station
• Space Frame
• Light Guide Map
• Connectors
• Patch Panel Connectors

2
StationsModifications to the Carbon Fibre
The New station has had its outer diametre
reduced to 396 to take into account the fact that
the bore of the solenoid is not machined but a
rolled tube. The connector flange has been
thickened to 3mm to allow machining. This is to
ensure that there is a uniform thickness thus
ensuring that the completed tracker is of one
axis and all planes are parallel. Also the face
that seats the connectors has a completely
machined face to allow all of the connectors to
sit down flat thus keeping the axis of the fibres
perpendicular to the plane
3
Space Frame

• Modifications
• The components that are used to construct
  the space frame are similar to before with the
  exception of the locating foot and the diametre
  change. The foot was changed because of problems
  during assembly, if the dowel location was pushed
  into the foot there was no way to extricate it so
  the new foot has 2 smaller dowels either side of
  the structural tube.

Gluing Fillet Design
Old Foot Design
New Foot Design
4
Space Frame
Tooling The jigs that align the space
frames will need to be modified/re-made To
accommodate the new foot design and also to
match the new station to station pitch.
5
Station Layout/Pitch

• The final pitch has still to be decided but the
  two alternatives shown are
• Top-
• 15cm, 18cm, 20cm and 47cm
• Bottom-
• 15cm, 20cm, 18cm and 47cm
• If this is the case the only need for a
  decision is to accommodate the length of wave
  guide and Im sure we can accommodate a 2cm
  change in the lengths by making them the longest
  required.

6
Light Guide Map
View of the station onto the polished face of
the connector
Bulkhead Connector 5
Bulkhead Connector 1
Bulkhead Connector 4
Bulkhead Connector 2
Bulkhead Connector 3
This is the final version, assuming no one finds
any glaring mistakes, of the connector map for
the tracker it can be found in its full form at
http//www.hep.ph.ic.ac.uk/CAD/mice/finalmice
7
Connectors
During the test beam at KEK there was a
reduction in light output from the 4th
station this could be due to 2 or 3 different
reasons. To ensure that it is not the
connectors We propose to carry out light
ransmission tests thru both station and patch
panel connectors.
8
Patch Panel Hole Requirements
9
Positioning In The Solenoid
The tracker sits on 4 adjustable feet two at the
front two at the rear and held down by a
spring loaded pad, all made from PTFE. This
aligns the axis of tracker and solenoid
The tracker is aligned in Z And Phi by pulling a
locating Block into a Vee.
10
Assembly and QA for final MiceTracker

• Geoff Barber
• Paul Kyberd

11
Sequence

• Align the fibre plane onto the vac chuck assembly
  so that it is correctly placed for gluing to the
  station.
• Starting from the centre fibre, bundle the fibres
  into 7s and fit into the comb
• Scan the fibre plane to and ensure that it meets
  the requirements set down by the QA criteria.
• During the scan checks can also be made to ensure
  the correct bundling has been achieved and also
  we should by scanning with a second camera at the
  back be able to ascertain the quality of the
  mirroring on the closed end of the fibres.
• When happy that all is OK, take the fibres from
  the comb and fit the rubber sleeves and then fit
  them into there final positions in the
  connectors.
• The connectors can be fitted into a secondary
  bracket mounted off the vacuum chuck.

12
Sequence Continued

• When all the connectors for that plane are fitted
  the plane can be scanned a final time to ensure
  that the channels are in the correct positions in
  the correct connector.
• When all seems well the plane still fixed to the
  vacuum chuck are moved across to the gluing rig
  and the carbon fibre station and the fibre plane
  are glued together.
• Once the assembly has cured the connectors can be
  fitted into there correct positions on the carbon
  fibre flange, the fibres are not yet potted but
  held in the connectors by masking tape so as to
  allow the tidying up of the fibre runs.
• The whole process can now be repeated for the
  second plane although a great deal of parallel
  processing can haven by duplicating certain
  pieces of hardware.

13
Comb
14
Pros Cons

• Pros
• This scheme will allow for almost real time
  monitoring of the assembly procedure.
• We will get an instant feel for the integrity of
  the mirroring.
• It will allow us to check the middle plane and
  characterise it with the same accuracy as the two
  outer planes.
• Cons
• We have not tested this out and it may prove to
  be a little fiddly.
• We will need to make more of he existing hardware
  and develop a few new items.

15
Conclusions
There is still a number of items to detail and a
few tests to carry out. There are QA /assembly
questions to be answered but overall we are in
pretty good shape.
16
Addendum-Present Work

• We have just received the tracker back at IC and
  will start to investigate the 30 light loss.
• To arrive at the final quantity of fibre needed
  for the external waveguide I will be assembling a
  3D model of the area to allow us to calculate the
  fibre runs.
• Now we are not having vacuum in the solenoid bore
  I can detail the patch panel and try to find a
  manufacturer (I have had no response from the
  company to the request to design and build it).
• Set up a light guide chain to evaluate the
  connectors.
• Design the space frame assembly jigs once the
  final station pitch has been decided.
• Take the tracker alignment/location in the bore
  from concept to hardware.
• Set up the QA in the darkroom at IC and develop
  it into a working procedure.