MM mechanics meeting, H. Danielsson CERN

Panel components and construction

RomaPaviaSaclayCERN

14-15/4/14

In the two steps the glued pcb is on the granite table: this provides the good planarity.The thickness is 10.949 ± 16 μm in panels 1,3,4,5. Panel 2 is expected 0.16 mm thicker because of a thicker pcb used.

Vacuum bag method in Roma 1

5 panels for M2

Roma 1 / 14-4-2014

Two more panels 60 x 100 cm² were prepared to test the effect of the delay 6 h vs 24 h in the two steps approach. Better results are found for 24 hours.

To improve the correct thickness also in the frame regions a last panel, 60 x 68 cm² large and with 6 mm Al honeycomb, has been built with slices of honeycomb inside the Al frame.

Results:

The method and the measurements of the panels are reported in:

ATL-COM-MUON-2014-024

We decided to built a full size SM1 with this technique before this MMM Workshop but we had some delay in the procurement of the components.

Bottom side Top side

σ (RAW) µm 18.5 23.6

σ (FIT) µm

15.8 18.8

αx µrad 48 64

αy µrad

- 13 31

As an alternative to the insertion of the honeycomb in the frame we are now testing the use of a stiffback inside the vacuum bag while gluing the second panel.This should better garantee the same thickness in the frame and in the honeycomb region.A small panel 60 x 60 cm² is ready and will be measured Monday April 14th.

MM mechanics meeting, H. Danielsson CERN 14-15/4/14

MM mechanics meeting, H. Danielsson CERN 14-15/4/14

MM mechanics meeting, H. Danielsson CERN 14-15/4/14

MM mechanics meeting, H. Danielsson CERN 14-15/4/14

MM mechanics meeting, H. Danielsson CERN

On the issue of panel assembly and detector assembly (Alan)If the assembly is done using long pins (let’s say more than 50mm long) than the error if the base of the pin is not flat in contact with the marble leads to an innaccuracy of more than 60 microns... and this is just the theory - we can add a good 20 microns operator error to that!! The case of a pin long of 100mm with a diameter of 10mm leads to 100 microns sway!!!

ml,

STIFFBACK

Precision shims

V shaped blockto get precise and high repeatibility system

Stiffback mounted with short reference pins (L=30mm - ø 16mm) to guide PCB

Inserts placed with the Rasmasks tooling methodin a previous stage

ε’=L ε/l (for α small ) best case l=L (square)if L increases ε’ as well

L

l

ε

ε

ε’

α

α

α

L (mm) l (mm)if Ƹ=0.01mm than Ƹ’(mm)

if Ƹ=0.005mm than Ƹ’(mm)

50 16 0,0313 0,0156

100 16 0,0625 0,0313

100 10 0,1000 0,0500

Therefore proposition

14-15/4/14

MM mechanics meeting, H. Danielsson CERN

PLANS (CERN)NSW1

Glue the frame Test gluing of the mesh on a test panel Measure thickness

NSW2 New stiff-back with low CTE Possibly with foam New gas inlet Simplified frame pieces

Module 0 Design started FEM calculations stiff-back. The stiff-back is the key.

14-15/4/14

MM mechanics meeting, H. Danielsson CERN

AssemblyNSW 1

Stiff-back prototype for NSW2 and module 0 under constructionMaterial carbon fibre, honey

comb core. Carbon fibre in closeouts

14-15/4/14

MM mechanics meeting, H. Danielsson CERN

NSW 1

14-15/4/14

MM mechanics meeting, H. Danielsson CERN

Module 0 design

14-15/4/14

MM mechanics meeting, H. Danielsson CERN

FEM Calculations of stiff-back (preliminary)

From experience low CTE required

14-15/4/14

1

MN

MX

11121314

151617XY

Z

micromegas_vacuum_table_design

-.028015-.024902

-.02179-.018677

-.015564-.012451

-.009338-.006226

-.0031130

APR 11 201415:23:17

NODAL SOLUTION

STEP=1SUB =1TIME=1UZ (AVG)RSYS=0DMX =.028027SMN =-.028015

MM mechanics meeting, H. Danielsson CERN

Preliminary Results

100 mm thicknessMax deflection 30-40 mm (center)Weight 87kg

We are studying 200 mm thicknessMax deflection 20-30 mm (center)Weight 120 kg (!)

14-15/4/14