| 1700 | After removing and replacing the SQUET card on stripline 27, the short disappeared. |
| | Sealed up IVC and began pumping out. |
| 1830 | Turbo pump returned error E006 and turned itself off. It was not connected to the IVC as, although the turbo was on, it hadn't switched over from the backing pump. Turning it off and trying again resulted in a similar problem. During the second attempt, turning off the turbo pump but leaving the module resulted in a warning. It looks like the turbo pump needs to be repaired. We cannot cool down without a turbo pump, so may have to commandeer Little Blue's. |
| 1930 | Complete maintenance on 1 K pot pump. Replaced internal demister and gasket, and cleaned inside of pump. Ran a quick test after filling with oil and everything appears fine. Turned off until tomorrow so that somebody is present for an extended test in case something goes wrong (such as oil leaking out of the pump). |
| 2250 | Retightened bottom IVC flange. Two screws have stripped heads, so were impossible to tighten. This may result in a leak, but is probably worth cooling down anyway. |
| 2315 | Repeated test with turbo pump and it still refuses to switch over to backing pump. Digging further into the manual seems to indicate that turbo is not attaining final rotation speed in a suitable amount of time. Final rotation speed should be 90,000 rpm, and turbo appears to be climbing very slowly from 50,300 rpm. Manual suggests this could be due to a high fore-vacuum pressure, leak or insufficient cooling. However, ambient temperature in the laboratory is not unusually high at 23.8 degrees C, and the valve before the turbo pump is closed so there is no chance of a leak or high fore-vacuum pressure. Another possibility is that the bearing is defective and the rotor is running hard. However, the bearing is not making any unusual noises. Manual suggests extending run-up time or lowering rotation speed. Suspect bearing may be the problem as pump has been run pretty hard for the last few years, so do not want to make the problem worse. Shall contact Pfeiffer on Monday. |
| | Leave IVC to evacuate overnight using scroll pump. |