Friday, April 10, 2009

Day 16, 4/10/09 -- 4.2K here we come!

Wow, has it really been 2 weeks? It really only feels like 12 or 13 days, tops.

Today was an eventful day for everyone in the high bay. Matt Dobbs from McGill (Kevin and Fran├žois' advisor) arrived late last night and showed up at the high bay for the first time this morning. Shaul left around 10 AM to drive to Albuquerque for his flight back to Minnesota.

In the morning we talked to the CSBF guys Hugo and Mark about modifications to our truck plate to allow it to mate more easily with their launch hardware. The modifications should be quick and may even save us nearly 10 desperately-needed pounds.

Jeff and I filled the cryostat with liquid helium today. The first step in this process was removing the liquid nitrogen from the helium tank, accomplished by dropping a tube to the bottom of the tank and then pressurizing the tank to force the liquid out the tube. Once the nitrogen was gone, we were able to fill with helium. I worked on fixing our liquid helium level sensor, but I messed up and it's too long, and I'll have to fix it tomorrow.

Joy and Daniel spent the day working on the ACS sensors, culminating in suspending the gondola for preliminary scan tests. They're planning on staying late tonight to do some tests with the star camera. Fran├žois and Hannes worked on getting the detector hardware ready to go while Matt and Kevin worked on software.

Because we've filled with helium, the superconducting bearing holding the half-wave plate can cool below its transition temperature. Shortly before we left for the evening, Jeff ungripped the HWP and was able to rotate the system inside the cryostat by hand from the outside shaft feedthrough -- a critical first test passed!

Because things inside the cryostat are still cooling, we have to fill helium fairly often as we draw the heat out of the components inside. Thus, Jeff and I will be headed back to the lab at about 4AM to fill the helium tank again. Hopefully we'll only have to do this once, and as a reward to ourselves we'll be taking a field trip in the morning -- but I'm not going to give away the surprise for those who don't already know...

As promised, more pictures today:

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