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

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

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

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

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

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

T.Schneider/LHCb Muon EDR 4.a) Viscosity test Adekit 140 Adekit 145 Araldite 2011 3M DP490 3M DP460 16/04/2003 T.Schneider/LHCb Muon EDR

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 140 Adekit 145 Araldite 2011 3M DP490 3M DP460 16/04/2003 T.Schneider/LHCb Muon EDR

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

T.Schneider/LHCb Muon EDR 4.b) Electrical resistivity Results: A145 A140 Araldite2011 DP490 DP460 <0.1nA 0.9nA <0.1nA 0.8nA <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

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

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

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

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

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

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

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