Mechanical robustness & associated tension at the DSSD slant part connection Mar-5 th 2013 B2GM KEK S. Uozumi (KNU), T. Tsuboyama, N. Sato (KEK) PF1/PF2 F-Hybrid DSSD B-Hybrid PB1/PB2

Slant DSSD assembly Assembly of slanted sensor is not straight forward. – Wire bonding should be done when DSSD and hybrid are flat on a jig. After boding, they are bent. – Length of top and bottom pitch adapters should be adjusted so they will run parallel after bent. Gluing of kapton flex: – The width of glue should be at least 3 mm. Otherwise the glue is peeled when bent. – In case of SVD2 a glass piece is inserted and glued. – In order to add 2mm in forward region, a modification is necessary. Rib, mount block, flex length. DSSD T. Tsuboyama (KEK) PXD-SVD meeting, 5 Feb 2013, Watzler, Germany 2 3mm From T. Tsuboyama PXD-SVD meeting Feb

Concerns 1. Width of glue areas are narrow. Are these robust enough? 1 mm for DSSD – capton cable ~2.2 mm for capton – hybrid side 2. Cable length is tight. Any deformation of DSSD due to associated tension from the capton cable ? Cable-cable contact makes another bad effect? CAD simulation (Onuki-san) also implies similar concerns. Though no realistic check had been done so far. 1 mm 2.2 mm 11.9 mm This picture Is not to scale. Bottom-side cable length = mm

Concern 1 : looks OK Quickly examined by handy mock-up. 1 mm width of glue area seems robust enough, not as we concerned. However note that this is a test with not really exact material! SDDS -> Aluminum plate Capton -> copper foil Hybrid (0.67mm thick) -> slide glass (1.2 mm thick) Gluing Araldite -> double-sided tape Final confirmation with fully realistic setup may be needed ?

Concern 2 : dummy-DSSD deformation exam setup Again Note : This exam is not exactly realistic !! Hand-setup … accuracy > 0.5~ 1 mm Silicon DSSD -> dummy made by Aluminum Hybrid material and thickness (0.68mm) -> glass 1.2 mm Glue -> double-sided tape Capton cable -> copper film Distances measured by laser Hand-control stage for horizontal movement

The DSSD edge part is tensioned by tightly arranged cable, resulting in visible deformation.

To suppress deformation, put a fixer block at the end of dummy-SDDS by double-sided tape

With fixer block

Measured dummy-DSSD deformation Farther (pull)Closer (push) Slope of linear fitting : Default … 1.37 With fixer block Pushing side … 0.20 Pulling side … 0.71 In pulling-side, fixer starts peeling off

Solution ? Fixer block is an effective solution anyway, but “existance of tension” seems to be origin of the problem. If we want “tension-free connection” … – Too tight cable length seems to be making tension. – The tension applied to DSSD with non-zero angle makes deformation. – However we must be careful to avoid “contacting cables” situation which makes an another tension problem. – Arrange “self tension-absorbing” cable in limited space ? Do we even need some more space for it?

Solution ? : “Naha” philosophy again The holes for ribs and mount blocks are not for rotation. The symmetric structure (right) was necessary as these parts formed the rotation mechanism. If rotation is not necessary, a slim and long structure (larger moment) will be better if total area is kept same. DSSD T. Tsuboyama (KEK) PXD-SVD meeting, 5 Feb 2013, Watzler, Germany From T. Tsuboyama PXD-SVD meeting Feb

Summary Robustness of slant part DSSD-cable connection is examined with hand-made setup and handy materials. Although the setup with limited reality may be making the exam result pessimistic, at least we can say : - Current design of slant part connection is tight. Tension between DSSD and cable presumably exist, or safety margin is very small. - It may make concerns on heat-expansion, vibration, assembly procedure. It is desirable if the design is reconsidered to be safer toward “tension-free” connection. Putting fixer block is worthwhile anyway. Final exam with realistic geometry & materials will ensure safety. (possible in IPMU during ladder mockup assembly? )

Backups

Length of Origami/PF/PB It looks the present length of ORIGAMI PCB, PF1, PF2, PB1 and PB2 is determined from those models. I already submitted all the flex circuits. – I would like to know how tolerance this structure have. We still have some time to change length. DSSD T. Tsuboyama (KEK) PXD-SVD meeting, 5 Feb 2013, Watzler, Germany 15 From T. Tsuboyama PXD-SVD meeting Feb