Measurements of thermal properties of hybrid stave prototypes

Talk presented at the ATLAS pixel mechanics meeting (CERN, 7 November 1997)

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C. Caso & F. Gastaldo/INFN-Genova


General scheme: The experimental set up consists of:


The binary ice machine (water-ethanol) is operated under pressure. From January '98 it will operate with water-methanol.




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PROBLEMS


    1 mm grease hybrid prototype started giving anomalous results (positive temperatures when heated) after 1 week of operation. Stave open.




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    Test of failure on 0.1 mm grease prototype

      coolant turned off whit power on
      silicon side --> + 90 °C
      power off, let it cool down and coolant turned on
    Temperature profile gets higher by ~ 8 °C and not uniform.

    Tests of thermal shock on different greases.
    Grease samples hosted in a stave put in a oven at 100, 150, 170 °C (~ 5 min). Put in a freezer at -28 °C (~ 20 min).
    Visual inspections.

    • AIT CGR7018 presents bubbles, it is harder and dryer.
    • DOW CORNIG 340 has got no visible modifications.