The Stave Thermo-Conductivity QC Procedure Idea P.Netchaeva, A.Pozzo INFN Genova The piece (half) of the ex-baseline stave #8 has been used. P.Netchaeva INFN Genova

The Idea The baseline stave (with Al tube inside) transverse thermoconductivity must be estimated before attaching modules. This can be done: Using heaters. The temperature is being measured on the surface of the heater (not C-C). The procedure of applying heaters is rather complicated itself (reproducibility?). The stave after QC procedure should be cleaned. Joule effect. We can use the resistance of the stave itself to simulate working modules. R stave ~ 5 Ohm (due to the glue between 2 tmt!) R half-stave = 0.2 – 0.3 Ohm P.Netchaeva INFN Genova

The Setup with Heaters 4 heaters: I = 1.07 A , U = 24.0 V, W1 = 6.42 W Cooling: water 17.6 oC (+ air -> turbulent flow) water P.Netchaeva INFN Genova

The Joule Effect R half-stave#8 = 0.24 Ohm I = 12.5 A Cooling: U = 3.0 V water 17.6 oC W1 = 6.25 W (+ air) Electrical contacts: + Indium water P.Netchaeva INFN Genova

The Joule Effect: Thermocamera images Water direction Water direction P.Netchaeva INFN Genova

The Joule Effect vs. Heaters The temperature has been measured on the surface of the heaters water P.Netchaeva INFN Genova

Temperature vs. Cross-Section The temperature has been measured on the 4 central shingles of the half-stave P.Netchaeva INFN Genova

The Joule Effect vs. Heaters: ~16W / module water P.Netchaeva INFN Genova

Conclusions The “ideal” stave (without Al tube inside) has been used. The Joule effect heating method gives the temperature distributions along the “ideal” stave corresponding to those we get from the method with heaters simulating real modules. Using the Joule effect we measure the temperature directly on the carbon-carbon, while using the heaters we can measure the temperature only on the heaters surface. Applying the heaters we introduce a systematic error due to non perfect uniformity of the thermal grease between carbon-carbon and heaters. Further tests on the baseline staves (with Al tube) are needed. P.Netchaeva INFN Genova