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Summary of TS2 activities on CO2 vacuum insulated lines on YB0

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Presentation on theme: "Summary of TS2 activities on CO2 vacuum insulated lines on YB0"— Presentation transcript:

1 Summary of TS2 activities on CO2 vacuum insulated lines on YB0
Monday the 31st of August: connection of vacuum groups on sector 5 and 14, static measurement of vacuum Sector 5 Sector 14 1053 – 2.9*10-3 mbar 1054 – 7 mbar *10-3 mbar *10-2 mbar 2nd and 3rd of September Flushing with Ar (pressurizing and depressurizing) on all 8 loops Total 20 cycles per loop Wednesday the 9th of September: circulation test sector 5 and 14 at -25 C coolant Sector 14 was bad (9C on surface), sector 5 was ok (17.5 C on surface) On Friday 11th of September, sector 5 and 14 pipes have been disconnected from vacuum groups & a circulation test repeated Retention tests performed after 1 hour gave the following results: Sector 5 1053: 2.2*10-4 mbar 1054: 1*10-3 mbar 1055: 1.1*10-4 mbar 1056: 6.4*10-5 mbar Circulation test: sector 14 was still bad (10 on surface), sector 5 was ok (16 C on surface for -30 C process). It was realized that temperature gauges on the sector 14 vacuum jacket surface are located very close to the connection box, and they were displaced some 30 cm away. Once stable again the sensors read 20 C. *10-4 mbar *10-4 mbar *10-3 mbar *10-4 mbar Sector 14 1060: 1.1*10-4 mbar 1057: 5.9*10-5 mbar 1059: 1.1*10-4 mbar 1058: 4.9*10-5 mbar

2 Junction boxes We have 2 junction boxes on each sector
One box is almost accessible at the periphery of the detector: we can add insulation almost on each sector, we can move the temperature gauges We cannot access at all the boxes on the vacuum tank (one per sector), unless opening of the barrel wheels: assessment on T gradient necessary! Old position of surface Temperature sensors, sector 14 New position of surface Temperature sensors, sector 14

3 Wednesday 9th of September – Active vacuum Sector +14
Vacuum jacket temperatures (near junction boxes) 3 kW on the dummy load Min temp = 9°C at loop 1060 -20 °C SETPOINT -25 °C SETPOINT Four loops opened Leaking loop PP1 bypasses temperatures

4 Friday 11th of September – Static vacuum Sector +14
Vacuum jacket temperatures (near junction boxes) 3 kW on the dummy load Min temp = 18°C at loop 1057 -25 °C SETPOINT -30 °C SETPOINT Four loops opened PP1 bypasses temperatures

5 Wednesday 9th of September – Active vacuum Sector +5
Vacuum jacket temperatures (near junction boxes) 3 kW on the dummy load Min temp = 17.5°C at loop 1053 and loop 1055 -20 °C SETPOINT -25 °C SETPOINT Four loops opened PP1 bypasses temperatures

6 Friday 11th of September - Static vacuum Sector +5
Vacuum jacket temperatures (near junction boxes) 3 kW on the dummy load Min temp = 16°C at loop 1054 -30 °C SETPOINT Four loops opened PP1 bypasses temperatures

7 Open points How long would the vacuum remain in the good range? Can we trust static vacuum for long term performances ? How do we tackle the issue of the junction boxes ? Can we have a better “on-line” performance evaluation (vacuum rather than T?)


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