1. ATLAS-NSW CERN MMM workshop assembly of the module (quadruplet)
Patrick PONSOT for the CEA-Saclay-Irfu group:
F.Bauer, P.Daniel-Thomas, E.Ferrer-Ribas, J.Galan, W.Gamache, A.Giganon, P-F.Giraud, P.Graffin, S.Hassani, S.Herlant, S.Hervé, F.Jeanneau, H.LeProvost, O.Meunier, A.Peyaud, Ph.Schune
21-22 of February 2013

2. OUTLINE Principle about the planarity of the PCBs
How to build a flat double plane (// at 80µm)?
How to keep under control the deformation of the 4 PCBs inside a quadruplet (only one in-plane alignment system per quadruplet)?
How to align the PCBs during assembly of the doublet or quadruplet?
Saclay’s plan
2013/02/21-22
CERN MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT

3. Principle about planarity
Planarity of the PCBs should be better than 50µm. The baseline: Doublet are made of thinner PCBs with honeycomb (or foam)
The planarity is given by the symmetry of the structure (assembly procedure should provide this, no asymmetric residual constraints…)
Better is the symmetry, better will be the planarity
Planarity is coming from the assembly procedure
2013/02/21-22
CERN MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT

4. Principle about planarity
Planarity of the PCBs should be better than 50µm, is it possible to get it only with spacers?
Planarity of the assembly is partially destroyed by the stiffness of the PCBs which try to recover their initial geometry
Between spacers there is nothing to avoid this effect
2013/02/21-22
CERN MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT

5. Building a flat double-plane
How to build a flat double plane (// at 80µm)? Each proposal should be checked with tests?
With honeycomb and glue compensation for parallelism of the 2 PCBs (will be tested at Saclay)
With additional calibrated spacers inside the honeycombs to control the parallelism of the 2 PCBs during the gluing (tests are in progress at CERN)
By piling of planes with adjusted spacers at each gluing step (proposal from Hermann)
…etc.
Tests are planned at Saclay
Tests are done at CERN with the help of the Saclay antenna
Proposal from Hermann (Tests?)
2013/02/21-22
CERN MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT

6. Building a flat double-plane
Preparation of gluing tests at Saclay
A new marble (3mx2m) will be delivered on April (today, the size of our marble is 2mx0.9m)
An optical head on the CMM machine will be available on March
Material to do gluing with vacuum has been ordered
Measurements of the thickness of Nomex honeycombs has been done (9.96 to 10.01mm)
Gluing tests of the drift pillars have been done (results on the next slides)
Compression tests are performed at present, to estimate the maximum pressure that we can apply during gluing procedure without stress on the PCBs
…etc.
2013/02/21-22
CERN MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT

7. deformation of a quadruplet
How to keep under control the deformation of all the 4 PCBs inside a quadruplet with only one in-plane alignment system?
The idea is to glue drift pillars to distribute the deformation to all PCBs
Stress test of drift pillars:
Various geometry size of coverlay
(but thickness for all 128mm)
Pillars made out of ceramic or peek and either with a central “glue gap” or not
Glue  Araldite 2011
Tests performed with a bulked MESH or a standard MESH
5mm
2013/02/21-22
CERN MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT

8. Stress test of drift pillars
2013/02/21-22
CERN MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT

9. Stress test of drift pillars
Summary of the results (at least 3Kg are expected)
CERAMIC
PEEK
“Glue gap” CERAMIC
Copper
Tear 9.6kg
Tear 6.3kg
Tear 8.4kg
Copper + Coverlay
Tear 10.5kg
Tear
pillars + standard Mesh
Tear 10.87kg
Pillars + bulked Mesh
Broke 11.08kg
We have a conclusive gluing process – CERAMIC wins
2013/02/21-22
CERN MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT

10. Layout of the PCBs proposed by Rui
Alignment of the pcbs
How to align the PCBs during assembly of the doublet or quadruplet?
Against pins fixed on the marble (as for sTGC)
Or with Rasnik© alignment systems (masks could be done directly on the PCBs)
An optical test will be done with reducing of the thickness of the PCB (0.2mm) to define if we can form the image through the FR4
Layout of the PCBs proposed by Rui
2013/02/21-22
CERN MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT

11. Saclay’s plan Measurement of the stiffness of a composite panel
Mock-ups and a stiffener will be done to define a more realistic Young modulus for simulation (1mx0.6m)
Measurement of the deformation of a doublet (mechanical and thermal loadings)
3 stiffeners will be done to study the distribution of the deformation with the spacers glued in the drift gap (ceramic pillars)
Contribution for mechanical prototype with 4 modules (quadruplets)
Design and simulations
Building of the largest module (M4) …
The construction of a small operational quadruplet (1.2mx0.6m)
The idea is to identify the main problems to prepare the study of the module -1
2013/02/21-22
CERN MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT

12. DSM Irfu SIS/LCAP (PC N°12, Bt 123) Patrick PONSOT
Thank you for your attention !
Commissariat à l’énergie atomique et aux énergies alternatives
Centre de Saclay | Gif-sur-Yvette Cedex
T. +33 (0) | F. +33 (0)
Etablissement public à caractère industriel et commercial | RCS Paris B
DSM Irfu SIS/LCAP (PC N°12, Bt 123) Patrick PONSOT
CERN MMM workshop - CEA-Saclay/DSM/Irfu - Patrick PONSOT
2013/02/21-22