2013/03/30
| 1200 | Close V1, V2. Open vent speedivalve. G2 ~ 7.4 mbar and decreasing. Turn off He-3 pump. Internal leak rate of leak checker: 1.03E-10 mbar*l/s. |
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| 1212 | Isolated He4 pump, opened leak checker to fridge lines. Leak rate rose to 1.8E-4 mbar*l/s and then slowly dropped. G2 ~ 4.4 mbar. |
| 1220 | Close V13A and B. Saw G2 rise. |
| 1235 | Installed styrofoam cup phone, aka “Styrophone”. Functional and helpful! G2 at 23 mbar and leak rate is 1.2E-8 mbar*l/s. Begin leak checking by opening V13A and V13B. Leak rate rose to 1.4E-4 mbar*l/s. |
| 1242 | G2 at 11.2 mbar. |
| First leak test conducted with syringe. The highest two flanges + the speedivalve being sprayed seemed to result in a rapid increase of the leak rate to 1.6E-4 mbar*l/s. Stopping the spray test, leak rate lowered to 1.3E-4 mbar*l/s. It seems that at this rate the leak rate background started to decrease more steadily. | |
| 1245 | Leak rate has decreased to 1.04E-4 mbar*l/s. G2 at 3.8 mbar. The first round of checking all flanges above pump (and accessible by leak detector) produced no gross leak. Re-testing the top flanges/ valve did not reproduce the initial higher leak rate. |
| Background leak rate is 5.53E-5 mbar*l/s. | |
| 5-10 minutes later, conducted liberal spray test over all flanges, starting with a leak rate of 4.2E-5 mbar*l/s (and dropping). | |
| 1315 | Leak rate 3.0E-5 mbar*l/s and decreasing. No sign of gross leak. A small increase was detected, but re-tracing steps did not reproduce it. |
| 1324 | Background leak rate: 1.97E-5 mbar l/s. G2 ~ 1.7 mbar. |
| 1330 | Switched spray operators. Background leak rate: 1.5E-5 mbar*l/s. |
| 1345 | Detected a large leak in valves right above pump. Maxed out at 4.6E-5 mbar*l/s. Should use the syringe again. |
| 1410 | Background leak rate: 1.76E-5 mbar*l/s, G2 ~ 2.3 mbar. |
| 1420 | Leak rate rose from 8.8E-6 mbar*l/s to 1.3E-5 mbar*l/s. Significant leak detected when spraying around the pump. |
| 1445 | Covered the end of the pump where the oil case panel is with plastic (taped. down). Also covered suspect flanges above pump with plastic. No picture, unfortunately. |
| Background leak rate: 9.8E-6 mbar*l/s. Rate increased to 2.4E-5 mbar*l/s due to spraying (without syringe) of the bottom of the oil case front panel. | |
| 1457 | Leak rate maxed at 3.95E-5 mbar*l/s. |
| 1510 | Begin spraying on oil plugs on pump with syringe. Background rate: 1.12E-5 mbar*l/s. |
| 1555 | Slight increases in leak rate were detected several times ( ~ 0.1E-6 mbar*l/s) and then spraying would be stopped to try to determine location of leak. However, trying to localize the spot around the plugs proved to be very difficult. |
| 1622 | Covered back of the pump and over the motor with plastic. Placed the clear hose without syringe into back of pump above motor. The background leak rate started at 5.22E-6 mbar*l/s. |
| 1625 | A sharp increase in the leak rate occurred - not levelling off. |
| Turn off gas supply; G2 rose slightly ( ~ 3 mbar). | |
| Leak rate maxed at 3.75E-4 mbar*l/s. | |
| 1700 | Now using syringe to re-produce leak. Leaving syringe in above motor at back of pump. Current leak rate at the start of this test: 1.5E-4 mbar*l/s. |
| 1706 | Leak rate starting to increase. |
| 1711 | Stop gas supply. Leak rate at this point: 1.88E-4 mbar*l/s. This was high/different enough to indicate that a leak is definitely there. |
| Leak rate maxed at 2.24E-4 mbar*l/s. | |
| 1812 | Isolate leak checker. Background seemed stable at 5.5E-5 mbar*l/s. Open He-4 pump to fridge lines again. |