M. Alfonsi LNF/INFN Cagliari 5 May 2006 M1R1 mechanical requirements Space constraint Frame and...

M. Alfonsi LNF/INFN Cagliari 5 May 2006

M1R1 mechanical requirements

Space constraint Frame and pannel Pads readout and trigger sectors Gas inlet and outlet

Low material budget Gem foils Honeycomb technology


Beam Pipe

The space around the beam pipe is the major constraint for the panel dimension

and electronics construction


Honeycomb gas outlet

Cathode Panel

gas fitting

HV Panel

GEM Chamber side view

GEM Chamber top view

G1G2G3

PADs Panelgas inlet

7 mm

GEM Chamber Layout


Mechanical detector design

The cross section of a GEM Chamber Module

Pads PCBCathods PCB

bushing


G10 FRAMES


Frames layout Active area -Frame

3 mm - 7 mm

Frame Width 18 mm – 30 mm

Frame Thickness 1mm 2mm 3mm

6 holes for decoupling resistors

4 hole pins

Two glue roads(1 per size)

Glue road wide 6 mm


Position

Frame Thickness

Frame+glue

Thickness x

1 2,99 3,02 0,03

2 2,99 3,08 0,09

3 2,99 3,00 0,01

4 2,92 2,96 0,04

5 2,95 2,98 0,03

6 2,98 2,99 0,01

7 3,00 3,04 0,04

8 3,04 3,05 0,01

9 2,96 2,98 0,02

10 2,96 3,00 0,04

11 2,95 2,97 0,02

12 2.96 2.98 0.02

mm 2.98±0.03 3.00±0.04 0.03±0.02

1 2 3

4

5

6

789

10

11

12

Glued-Frame Planarity

Glue thickness 20 m

Frame thickness rms 30 m


GEM FOILS


The GEM Foil layout

200 mm

240 mm

34 mm

Holes for SMD decoupling resistor

G10 Frame


Gem Layout G1

Three different type of GEM foils

Difference only for final HV electrodes

6 sectors for a totalactive area of 200 x 240 mm2


Gem Layout G2

The sectors towards the cathode


Gem Layout G3

References for frame gluing


Sag measurements

Different loads on the 40x40 cm2

GEM foils have been applied :

80 g , 160 g , 240 g

Measurements on 25 points

30 Kg/side30 Kg/side


GEM sag measurements

The GEM foil with a stretching of 30 Kg per side (~1Kg/cm) shows a bending of 100 m

on central region when a distributed load of 100 g is applied, equivalent to a pressure of 0.1 mbar.

The electric field producea load of ~ 0.01 mbar.

The total bending due to an electrostatic load should be of the order 10m.

The LHCb triple GEM detector is built without spacers

80g 160 g

240g 0 g


Kapton Radiation Hardness

C= 251 pF C= 277 pF

C= 234 pF C= 266 pF

C = 32 pFd>= 120 m

After Aging

C = 26 pFd>= 94 m

Before Aging

After aging a sag increase of 30 m corresponding to3 m in normal condition after 4 LHCb years

Mechanical load 10 times the electrostatic pressure


HONEYCOMB PANELS


Honeycomb Panels

Pad Panel

Cathode Panel

192 pads192 pads

Gas outlet

Gas inlet


machined reference ALCOA plane

Honeycomb panel technology

back-plane: (1 mm) FR4 – single side (12 m) Cu

vacuum bag3M–epoxy film

Cathode/Pad-PCB: (1 mm) FR4

gas insert

8 mm NOMEX honeycomb


PCB and 3M filmThe PCB are prepared :

Cathod PCB Cathod PCB Pads PCBPads PCB

appling the 3M film after

gluing the gas inserts on PCB before


HoneycombThe honeycomb is placed on top of 3M film cutting the nomex in corrispondance of gas insert and pins

Gas insert :Stesalite and alluminum

Alcoa frames

Pins

The backplane with a 3M film is put on top of Nomexand everything is put in a oven at 80°C


All panels will be checked for planarity with a 3-D machine at LNF. The measurements will be performed on a grid of 35 points.

3-D machine

5 10 15 20 25 30 35

4 9 14 19 24 29 34

3 8 13 18 23 28 33

2 7 12 17 22 27 32

1 6 11 16 21 26 31

Panel Planarity Measurements

Measurement points


3 Pad panels 3 Cathode panels

Panel Measurement

Thickness rms 35 m Thickness rms 23 m


Pads layout Trigger sector


Detector (“single gap”) performances with ground lines between pads are better than those obtained

0.6 mm 0.4 mm

Pad-PCB layout

No Aging effect on pads !


Detail on GEM Chamber


PAD -> 36 μm Cu 1.43 cm 0.25 % 2 mm G10 19.4 cm 1.03 %18 μm Cu 1.43 cm 0.13 % 1.42% X° 1 μm Ni 1.42 cm 0.007 % 0.15 μm Au 0.33 cm 0.005 %

GEM -> 10 μm Cu x3 1.43 cm 0.21 % 0.26% X°

50 μm kapton x3 28.6 cm 0.05 %

CAT -> 0.15 μm Au 0.33 cm 0.005 % 1 μm Ni 1.42 cm 0.007 %18 μm Cu 1.43 cm 0.13 % 1.42%

X° 2 mm G10 19.4 cm 1.03 %36 μm Cu 1.43 cm 0.25 %

3.10%Globally 3.1 x 2 (ch.s) = 6.2 % + 1% (FEE uniformely spread ) = 7.2%

Detector Material Budget

M. Alfonsi LNF/INFN Cagliari 5 May 2006 M1R1 mechanical requirements Space constraint Frame and...

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