Update on Module Mounting on Staves and Stavelets and a description of how the new system will work 11/7/11

Stage delivery They are here at RAL, arrived 6/7/11 Some key data..... XY resolution 0.250microns Z resolution 1.0 micron XY Repeatability +-0.75 micron Z repeatability +-0.7 microns Flatness etc +-14 microns All up mass 200kG Long stage is 1937mm long Travel 1500mm Short stage is 686mm long Travel 300mm They are here at RAL, arrived 6/7/11

Safety system components have arrived One of 5 emergency cut outs Safety interlock box with safety relays, double contactors, etc, etc Rx Tx table Safety light curtain Still awaiting corner mirrors

Roving Work Station Emergency stop 2 screens for software PC + keyboard etc Boxes for ‘bits’ Antistatic wheels and surfaces

Vacuum system

Real bits Extruded section of vacuum pipe Assembled unit clips connectors Assembled unit Vacuum reservoir

Equipment rack (27U) Houses... stage controller Interlocks + ??? Stave storage with N2 supply

How does the new system work? Basic concept is a development of the current module placement hardware and some of what we know from the original barrel module construction. I aim to construct only a single sided system ( that’s side A or side B rather than side A and side B) that can be expended for double sided activities.(side A and side B) It is large enough to fabricate a ‘1.6 meter’ stave.

Leaving room for this bit Making this bit Frames omitted for clarity End View of system

More fine adjusters to give theta and x adjustment Each module placement kit Walls divided into one module sections bolted to granite so no link module to module

Standard size 2400 x 1200 x 200 2000 X 1000 X150 1500 X 1000 X 100 So need two of these with T slots and custom legs. Need two because The access door is only 1600mm wide. We need to use standard bits. One table is not wide enough for 2 sided construction. Need special legs because. Because there are ducts in the floor of the room no leg may be closer then 0.5m from the duct. b) We need to bolt ‘stuff’ to the legs c) We must get the working height correct.

63mm wide We have almost sufficient Small ‘Y’ stages (15) from the hybrid placement system for the STC module construction Micromech stage still available (but preloaded with spring and we need a screw driven solution for positive drive.. Commercial solution using a differential screw

Under development at RAL is a 100micron/revolution differential screw adjuster to fit the Micromech stages. standard 5mm screw thread with a 0.5mm pitch Inside a 10mm rod with a 0.5mm pitch internal thread and a 0.6mm external thread giving a differential screw of 0.1mm/revolution.

Automatic Terrain following jig. Gap set at manufacture View in Y. Surface finding contacts not shown in this view Automatic Terrain following jig. Gap set at manufacture

Other bits The stages are only good at +-14 microns in X and Y over their length, so it’s not good enough to use without some other assistance IF alignment needs to be better than that (and I assume it does, like 5 microns silicon to silicon). So....use a laser fired back into the camera as a reference.

To do ...Speckle patterns, target patterns, power load into camera pixels.

Other stuff Safety:- We must have a robust safety interlock system. So..we will have emergency buttons on each of the 4 corners of the granite table and one on the roving control table. These interrupt the mains power via the interlock box to the stages. The Z stage is screw driven and hence holds it position but X and y stage are linear motors so will not hold their positions and become free running. Additionally there is a safety light curtain that is linked to the programmable E stop of the control box such that when the beams are broken no motion may occur but the stages are powered. A transmitter and receiver pair plus two corner mirrors will provide cover on all 3 exposed sides. 2) Vacuum:- A) Because of the nature of the item being constructed (1.6 metre long) we need a distributed vacuum system that allow connection and disconnection without loss of vacuum to surrounding components.

Logical Steps (assuming that the Stave(let) has been cleaned, checked, and all metrology completed) Perform metrology on the frames to get relationship of frame fiducials to mounting brackets. 2) Take module position data from drawing. Combine info to get module positions relative to frame fiducials. (The above is one solution, there is another) 4) Insufficient travel for a single pass for ‘1.6m’ stave. (edge to edge of silicon is approximately 1572mm) So need two ‘bites’ at it. No problem because the position of the reference fiducials on the stave frame is such that they are visible for two ‘fixed’ positions of the optics. 5) Accuracy of stage not OK for 5 microns in Y. Roll , pitch, yaw and all magnified by arms and height. So use a laser for correction. 6) Look up table for each outer frame that is bar-coded.(so some correction can be fed around the loop for the next item in the same frame).

7) Place frame on table and manually find the approximate positions of the pinholes. ( we should be able to position to better than 250 microns for any one frame so this should not occupy too long) 8) Let software do ‘soft alignment’ (same principle as Smart Scopes). 9) Transfer of module to vacuum jig/individual alignment kit is performed on the travelling workstation. Same concept as currently used but more tolerant spaces. Each stage assembly has a unique position. That way one does not start from zero positional knowledge every time. Software puts camera in correct position ( based on the laser and look-up table) so it’s up to the operator to do the final X,Y,Theta adjustment but the software tells the operator which way to go and by how much and accepts or rejects the solution. Traffic lights announce success (or otherwise). And record the errors for posterity. 11) Dry run a few positions. 12) Remove, (temporary storage not yet designed might be shift in X, or under the table or even over the table on a frame) . 13) Apply adhesive. 14) Refit and fine tune position.

If working on a 1.6 meter stave have to do new soft alignment for last two modules. 16) if working on side A and B rotate optics and move around other side of table and continue.

Some head line target numbers Accuracy. Some assumptions. a) Module placement is based on the fiducials on the top metal layer and does not include the mask placement errors. b) Plank/kapton mounting bracket tolerances are not included in the numbers. Y +- 5 microns for silicon to silicon X +- 5 microns for silicon to silicon. Z tracks the top of the kapton and is at the level of 100 microns + kapton. Number of modules/ side... up to 16. Number of modules in one operation 14. ( then need at X translation for the final 2 or need 2nd camera) Number of modules/day (8 hours), 24. ( based on the old SCT module where we built 6 sides (12 bits of silicon) in ½ day when all went well.

Possible Future developments Add second side. Add auto glue dispenser . Add second camera.