Request to update local DB limits for Outer System flex measurements

We’re currently building modules for the ITk tracker, and we’ve encountered an issue related to the flex size limits used during the upload of metrology data to the local database.

The problem arises because the flex size is not the same across all sections of the tracker.

For example:

• In Layer 1 (L1), the flex size in the y-direction (after the tabs are cut) is specified as 40.40 mm ± 0.100 mm, giving the local DB limits: [40.3 mm – 40.5 mm]. Drawing of L1 system: https://edms.cern.ch/ui/file/2771686/5/FabricationDrawing_RD53B_3L_Design_v4.2.pdf

• However, for the Outer System (our case, at Paris cluster), the flex size in the y-direction is 40.60 mm ± 0.100 mm, according to the fabrication drawing for V3.3 flexes, meaning the correct limits should be: [40.5 mm – 40.7 mm]. Drawing of outer system: https://edms.cern.ch/ui/file/2391603/5/FabricationDrawing_RD53B_3L_Design_v3.3.pdf

Currently, the local DB does not distinguish between flex types or the section of the tracker when validating metrology uploads. This results in our measurements being incorrectly marked as FAIL, despite being within spec for the Outer System.

Example cases are attached showing multiple flexes being flagged incorrectly due to this mismatch:

Our request is to propose that the local DB should include a dedicated limit configuration for the Outer System flexes, with the correct size: Limits for Outer System flex y-direction: [40.5 mm – 40.7 mm]

This change will allow correct validation of our metrology measurements according to the proper design specifications.

Thanks!