Module mounting

Status Stave 250 received… damaged – Repair now complete (see extras) Friday at 8:30 it will be collected by RAL driver and transported to QMUL At QMUL it will be thermally imaged, cycled and imaged again Assuming it checks out Ok it will return to RAL and have modules attached

In the mean time… Martin has been taken ill – we don’t know when he will be back (presently in the JR) At RAL we have been working out a plan of how to mount modules in his absence So far – We have repaired the stave – Started to prepare the in frame link pipes – Have a plan to realign the support blocks in the frame – Have found everything we need to mount modules except SE4445 – Have a plan to fabricate some bent modules to allow trial module mounting Presently – Ivan is aligning walls of module mounting tooling for a full stave – Peter and Tom (summer student) are making final DAQ etc preparations

Whilst the stave is at QM We hope to mount several glass plates Mount several bowed glass dummy modules Mount at least one mechanical sensor (if we can find one) Ideally mount one substandard electrical or a final module on a stavelet (needs finalising)

Conclusion Stave 250 looks quite good post repair QMUL need to verify it is as good as it looks We have a programme in place to prepare to mount modules without Martin We will be slower that Martin, but we are fairly confident we collectively have the necessary knowledge

Extras

Stave 250

Issue 1: Damage at Z=0 Closeout Delamination that extends almost to the screen Hole Consistent with a hard knock during transit?

The stave will be repaired at RAL - IW will doodle of end of stave close out and circulate The stave will then travel to QMUL in the back of a car where it will be – Thermally imaged at room temperature with water at +35C circulation – The stave will be thermally cycled 10 times between -25 to +35 If tests at BNL were less aggressive we will use their temperature limits – The stave will be thermally imaged at room temperature with water at +35C circulation a second time 9 Locations & Subsequent QA

Issue 2: HV pads are offset HV tracks on Stave 250 DC-DC tape are offset from pads on EoS by ~7mm

Design Considerations In principle - 10mm space available to fix this In practice -EoS thickness (2.3mm + glue) and the 45 degree rule for wirebonding mean maximum width of translation PCB, allowing for reasonable tolerances, is 7mm. The pads would ideally be ~200 microns in from the edge, >=500 microns long, and as wide as they are now. EoS 2.33 Translation Oxford (Roy W & Peter H) have started work on this “Translation PCB”

12 Large glue gap. Mounting tube NOT visible Small glue gap. mounting tube visible Issue 3: Placement of Power Tape with respect to Edge Closeouts “BAD” SIDE “GOOD” SIDE => We shall live with this feature

Background so we all understand the problem 13 On Stave 250 the shield plane edge lifts up at the joint between adjacent module positions The current adhesive application technique fills the hollows in the Kapton in one dimension only (room to spread in 1D) Peak to trough of 100 microns Y X Issue 4: 2D surface variations

FZ1 modules (as seen from above) typically concave. The two at RAL (from Cambridge) have 4 corners flicked up where the peak to trough is 250 microns I have positions on the stave where the Kapton is rises at the module to module joint. ( but not at every joint!) by about 100 microns. (this seems to be a new feature of the Kapton) There is a background feature that runs along the length of the stave that gives about a 100 micron peak to trough variation. (seen many times and the glue pattern was changed to cope with this) The glue can fill in undulations in one dimension only with the current application technique.(ie those features that runs along the length of the stave. It can not fill in both X and Y sets of variations. IF I increase the thickness of the initial glue layer to give better coverage of the worst areas (by asking the glue to spread more) then it will simply ooze out in those positions where the surface do not have this flicked up feature, nor will I be able to control it at the 4 corners. Remember that my jig has soft vacuum cups in the middle and edges along 2 of the 4 detector sides that run in the y direction. It remains to be seen if they will flatten out a module, of if I need to do some more work. It is also spring loaded to allow for variation in stave thickness of general overall flatness, so the glue gap is set by the feet of the jig or by the viscosity of the glue. 14 => Trials needed.

Stave Repair Ian, Peter, Cyril, Simon STFC RAL

Holes Drilled

FOAM

The Big Hole seen close-up

8 th July :30AM – – Injected ~4cc of West Epoxy G-flex into core through holes, – Closed holes with flash breaker tape – Stood on end (damage down) to allow glue to join skins.

9 th July :00am – Removed tape and inspected stave repair – All holes well filled with glue – Glue has also filled voids beneath damaged area – Small amount of surface glue on

Filling of extra holes Small amount of surface flue where the masking allowed a little build up Smaller crack on rear completely filled

Side without holes post repair

Side with holes post repair

Conclusion The repair worked better than expected All holes seem to have been closed It is no longer possible to lift laminates from the end/corners There is a very small amount of surplus glue on the surface – this will not be removed.