| 1520 | Commence leak check of IVC top O-ring flanges with a background leak rate of 1.3e-9 mbar*l/s. During initial leak test of top flange, leak rate rose slowly to 1.4e-9 mbar*l/s before settling back down to 1.36e-9 mbar*l/s. After test was completed the leak rate continued rising to 2.1e-9 mbar*l/s before dropping again. Leak check on bottom flange started with a background rate of 2.0e-9 mbar*l/s but rose to 4.8-9 mbar*l/s when the needle sprayed close to the top of the wizard staff. After letting the leak rate settle down, we tested the bottom flange again with a background rate of 1.9e-9 mbar*l/s. Spraying near the wizard staff resulted in a rise to 3.9e-9 mbar*l/s, indicating a leak (more likely the wizard staff than the bottom flange). We allowed the rate to settle back down to 2.1e-9 mbar*l/s before attempting the top flange again; rate continued dropping during test with no sign of leak. With background rate of 2.0e-9 mbar*l/s we tested the bottom flange again. We saw only a very slight rise in leak rate, until we approached the wizard staff. Near the wizard staff the rate again began to rapidly climb. Overall, test points to no leak in top IVC O-ring flanges, but a leak in the wizard staff. Commence unsealing IVC. |