Saclay, 18-19 April 2013 1

News from the lab

Large size Micromegas chambers

Givi Sekhniaidze / Joerg Wotschack

Saclay, 18-19 April 2013 2

Vacuum system• On the 2.8 x 2.8 m² granite table was located thin plastic

mesh for pressure distribution• Covered with 175 μm thick mylar foil with ø3 mm holes

Pump connectors

Saclay, 18-19 April 2013 3

L3 – Sketch-up

Gas distribution

Mesh frame support

frames

Saclay, 18-19 April 2013 4

Drift panel preparation – first skin

Saclay, 18-19 April 2013 5

Drift panel preparation – honeycomb

Saclay, 18-19 April 2013 6

Cross-bars

Long bars

Sucking heads

Drift panel preparation – stiff-back

Saclay, 18-19 April 2013 7

• 30x50 mm cross-bars – 1.2 m• 50x80 mm long bars – 2.5 m• Glued with Araldite 2011• 4-5 sucking heads per bar

Drift panel preparation – stiff-back

-10 0 -20 0 20 50 30

-70 -20 0 0 10 20 20

-40 -30 -30 -30 -30 0 0

-40 -20 -20 -20 -10 0 -40

-50 0 -50 -50 -50 0 20

-20 -30 -40 -50 -40 0 0

0 0 -50 -30 -40 0 -20

0 70 0 0 -10 100 120

-10 0 0 0 -10 10 10

-30 0 0 30 20 0 20

0 20 10 10 20 50 20

Repere A 50 60 60 70 70 100 80 Repere B

Long bars

Metrologic Shims

Stiff bars

Planarity (in microns)

12 rectified bars with4 or 5 suction cup

Saclay, 18-19 April 2013 9

X 12

VacuumClarinet gas

PCB

Using Skin suction Tool

Vacuum

Expansive glue

Vacuum

Precise shim

Skin

Saclay, 18-19 April 2013 10

Drift panel preparation – Mesh frame

Mesh

Cyanoacrylate

Araldite 2011

Drift PCB

Saclay, 18-19 April 2013 11

• 5 mm thick Aluminum frame mounted on the panel• Mesh stretched and glued on the frame• 3 special inserts for drift/read-out panel interconnection

Drift panel preparation – Mesh

Saclay, 18-19 April 2013 12

Drift panel preparation – Inserts (1)

M3 screw

O-ring

Pillars Insert Mesh

Saclay, 18-19 April 2013 13

Drift panel preparation – Inserts (2)

Saclay, 18-19 April 2013 14

Drift panel preparation – Inserts (3)

Saclay, 18-19 April 2013 15

Read-out panel• 0.5 mm thick FR4 external skin• 10 mm thick Aluminum honeycomb• External Aluminum frames

Saclay, 18-19 April 2013 16

Chamber assembling

Saclay, 18-19 April 2013 17

Chamber assembling

Saclay, 18-19 April 2013 18

Problems

• Due to the deformation of the stiff-back structure the distance between the PCB and the “half” panel was not correctly defined and problems appeared with the gluing. Along of the external Al frame and in some small areas also in the central parts of the PCB the glue is not attached correctly

• We found gas leak in the drift panel of L2 chamber. In the new drift panels the gas leak problem has been solved. The drift “old” panel of the L2 chamber will be replaced next week