1. T.Schneider/LHCb Muon EDR
Different application of epoxy glue in the muon chambers
a) Wire fixation on Anode wire bar
b) Bar gluing on the cathode panel
Peripheral gluing to close and seal the chamber
Epoxy glue requirements
Table of possible glue candidates
Additional test done for direct comparison:
a) Viscosity
b) Electrical resistivity
Attachment properties (shear test ISO9664)
Conclusions for the different applications
16/04/2003
T.Schneider/LHCb Muon EDR

2. T.Schneider/LHCb Muon EDR
1.a) Wire fixation on the anode wire bar
The 5mm wide glue line in front
of the soldering has to keep the
wires with a tension of 60g.
Low glue viscosity assures
that the 30µm wire is well
enclosed by the glue.
The glue line thickness shall
not exceed 1mm as we have
ground in only 2.5mm distance.
All Proto-types have been
done with Adekit 145
=> good experience
16/04/2003
T.Schneider/LHCb Muon EDR

3. T.Schneider/LHCb Muon EDR
1.b) Bar gluing on the cathode panel
Special tooling has been developed to glue the bars precise
(2.5mm ± 50μm) to the panel.
Function to the glue:
-Mechanical fixation of bars
on the panel. Wires pull with
~300gr /cm on the bar
-Filling the gap between bars
and panel (0.1mm-0.6mm
depends on thickness of the
chosen bar material)
-Provide sufficient gas
tightness for the chamber
16/04/2003
T.Schneider/LHCb Muon EDR

4. T.Schneider/LHCb Muon EDR
1.c) Peripheral gluing to close and seal the chamber
In some chamber design peripheral sealing is foreseen. Once
the HV and uniformity test of the assembled chamber are
satisfying this final procedure can be performed.
Function of the glue:
-Good attachment properties to keep
the chamber mechanically together
-High viscosity to facilitate the work
all around the chamber
-Provide sufficient gas tightness
for the chamber
16/04/2003
T.Schneider/LHCb Muon EDR

5. T.Schneider/LHCb Muon EDR
2. Epoxy glue requirements
- Working time >30min
Manipulation time < 8h
Good adhesive behavior for FR4 to copper/gold
Low viscosity for wire gluing
Medium to high viscosity epoxy for bar gluing /gap filling procedure to ensure mechanical strength and gas tightness
High electrical resistance (risk of dark currents)
Good chemical resistance (CF4/radiation/high el. field)
Good shock resistance (elastic behavior to avoid cracks and consequent leaks)
16/04/2003
T.Schneider/LHCb Muon EDR

6. T.Schneider/LHCb Muon EDR
3. Table of possible glue candidates
=>
16/04/2003
T.Schneider/LHCb Muon EDR

7. T.Schneider/LHCb Muon EDR
4.a) Viscosity test
Adekit Adekit Araldite M DP M DP460
16/04/2003
T.Schneider/LHCb Muon EDR

8. T.Schneider/LHCb Muon EDR
4.a) Viscosity test
Different Glue candidates have been applied to a declined surface
“structural” “low viscosity” “structural” “medium viscosity”
Adekit Adekit Araldite M DP M DP460
16/04/2003
T.Schneider/LHCb Muon EDR

9. T.Schneider/LHCb Muon EDR
4.b) Electrical resistivity test
Samples for volume resistivity have been prepared.
3KV have been applied to the samples under controlled condition
(T const, dry air)
Sensitivity of measuring device is 0.1nA
16/04/2003
T.Schneider/LHCb Muon EDR

10. T.Schneider/LHCb Muon EDR
4.b) Electrical resistivity
Results:
A145 A Araldite DP490 DP460
<0.1nA nA <0.1nA nA <0.1nA
(3.3TΩ; 130TΩcm) (3.7TΩ; 150TΩcm)
=>The 2 structural glues have lower volume resistivity !
The test of volume resistivity is more an academic approach. Real
conditions might be dominated by surface currents.
Tests are ongoing to get some answers on surface resistivity from the
epoxy glues. Reliable measurements are difficult to obtain due to
environmental conditions such as humidity and temperature.
Experience and results from Proto-types should enter into these
considerations.
16/04/2003
T.Schneider/LHCb Muon EDR

11. T.Schneider/LHCb Muon EDR
4.b) Attachment FR4 to Cu/Au
For good comparison for our special use (FR to Cu/au) a test for
“fatigue properties of structural adhesives in tensile shear”
( ISO 9664) has been performed in the CERN EST Division.
16/04/2003
T.Schneider/LHCb Muon EDR

12. T.Schneider/LHCb Muon EDR
4.b) Attachment FR4 to Cu/Au
Five samples per candidate (5) and condition (Cu or Au) have been
prepared =>50 in total.
Humidity and temperature were kept stable during this operation.
200mm wires were introduced as spacers to simulate the real
condition of our chamber construction.
16/04/2003
T.Schneider/LHCb Muon EDR

13. T.Schneider/LHCb Muon EDR
4.b) Attachment FR4 to Cu/Au
*Adekit 145 is only candidate for the wire gluing
The 4 others are possible candidates for the bar gluing and peripheral gluing
EST/SM-ME
Section de métallurgie / Metallurgy section
Rapport expérimental / Investigation report
16/04/2003
T.Schneider/LHCb Muon EDR

14. T.Schneider/LHCb Muon EDR
4.b) Attachment FR4 to Cu/Au
Apart from the Adekit 145 the result
are “quite similar”.
Best result for FR4/Cu : DP490
Best result for FR4/Au : Adekit140
Comments:
The 2 structural glues (DP490/Adekit140)
break in the glue. The glue stays on both
surfaces. The 3 transparent less viscous
ones (DP460/Adekit145/Araldite2011)
break at the glue metal connection.
16/04/2003
T.Schneider/LHCb Muon EDR

15. T.Schneider/LHCb Muon EDR
5. Conclusions for the different applications
16/04/2003
T.Schneider/LHCb Muon EDR

16. T.Schneider/LHCb Muon EDR
5. Conclusions for the different applications
Wire gluing:
We agreed to continue with Adekit 145 as we had quite good feed back in all our proto types. It was satisfying all requirements for this application (attachment, el. resistifity, viscosity, chemical resistance)
Calculating the attachment force corresponding to the wire surface in a 5mm wide gluing line the breaking limit is still factor 4 (2.3N0.6N wire tension) above our use.
16/04/2003
T.Schneider/LHCb Muon EDR

17. T.Schneider/LHCb Muon EDR
5. Conclusions for the different applications
Bar and peripheral gluing:
High viscosity to obtain good leak tightness as well as the attachment force are the most important properties for this application.
A good candidate is the Adekit 145. We decided to use this glue for the next chambers. This will give us soon answers about the missing chemical and electrical properties.
16/04/2003
T.Schneider/LHCb Muon EDR