Day 19, 4/13/05 -- The road to 250 mK

After a restful (hah!) weekend, work continues in the high bay. The cryogen boiloff situation has settled down substantially, and when I came in this morning I calculated roughly a liter per hour boiloff rate -- and things are still cooling. Based on the last run, though, we won't be ready to cool detectors until the 15th.

I spent a good part of the morning talking to Mark from CSBF regarding rigging and ballast hoppers. We checked with the CSBF electronics crew and it looks like we'll be able to put the ballast hoppers along the sides of the battery table, perhaps saving as much as 2 feet in height compared to mounting them at the bottom -- height that can be then used to lower our payload and provide much-needed clearance to our GPS antenna structure.

We noticed that the pressure in the cryostat has been slowly creeping upward starting yesterday, from a few microTorr to about 10-15 microTorr. Worried that there was a leak, we decided to leak check once more now that the pressure is low enough to check in the leak checker's more sensitive range. Luckily, we didn't find a leak, but we're still puzzled as to the origin of this strange increase. Also, I drove one of the NASA forklifts -- that was fun.

Jerry and Daniel stayed late last night after the clouds cleared and were able to take some images with the star camera that will be useful for debugging. Milligan found this morning that our spare flight computer board has been acting flaky and will need replacement. The gondola team also is finding that they're having issues with the serial ports on the flight computer crate and are actively investigating that (even as of now, roughly 11 PM). And the detector gang has been looking at SQUID noise in various hardware configurations of the instrument.

Luckily, while we've been waiting for the focal plane to cool, the weather has been nice: High 60's, fairly sunny, and not too much wind. Makes for good basketball weather. Sadly, it doesn't make for good basketball players -- watching a bunch of physicists play basketball is fairly comical.



Today's pictures:
http://picasaweb.google.com/asad137/EBEXInNewMexico041309#

Day 14, 4/8/09 -- the cooldown begins

Today we made the necessary preparations for cooling down the EBEX cryostat. We still had some concerns about the cryostat's pump-down rate, so we leak-checked again this morning and again found nothing untoward. It seems that our rental turbopump is just kind of slow.

Hannes spent the day installing SQUID controller boards onto the cryostat and installing all of the necessary cabling inside the RF-tight enclosure at the bottom of the cryostat. I attended our mission planning meeting with CSBF where we laid out our requirements and desires for the flight and worked on a model of the launch vehicle geometry so we can figure out how much height we have to play with.

At the end of the day, we started pre-cooling the cryostat, filling both the liquid nitrogen and liquid helium tanks with liquid nitrogen. This was uneventful, as planned, and the next day or so will be waiting for the relatively-isolated cold optics inside the cryostat to cool down.

Also, cowboy hats are awesome. I'm pretty sure I'm going to buy one tomorrow.

Pictures:
http://picasaweb.google.com/asad137/EBEXInNewMexico040809#

Day 1, 3/26/09 -- Coulda had a V6.

Thursday was a lovely day in New Mexico -- mostly sunny, and shorts-and-t-shirt warm. We got to the CSBF high bay at the Fort Sumner airport around 10 AM after a short stop at the local grocery store. There, we were informed that, yes, indeed, there are 4 restaurants in the town of Ft. Sumner -- and eight churches. Everything in town closes by 8:30 PM, except the liquor store (which is really just a part of one of the restaurants, Fred's) which closes at 10 PM.

Once in the high bay (left), we started the task of setting up our work area. We figured out where we wanted our computers to go and Milligan began setting them up near the Columbia computers. Jeff and I started uncrating the cryostat that holds our millimeter-wave receiver so we could put it on its cart and start putting the instrument back together.

We're currently sharing the high bay with another payload called FIREBall, an ultraviolet telescope designed for studying faint intergalactic emission. Their gondola is pretty sweet -- almost all made of carbon-fiber tubes and sweet spherical connectors between them (see pictures here).

Unfortunately, because the crane in our area of the high bay is way better than theirs, they asked to use our crane to install their delicate mirrors -- which meant they were in the middle of where we wanted to set up. That basically killed our afternoon, which is why there are so many pictures in today's album.

We went to eat at Fred's, and I was pleasantly surprised by the tastiness of my burrito thingy. On the way back, we decided to see what our rental Toyota Camry was made of...so we drove out onto the runway at the airport. Note: It was REALLY dark. None of the runway lights were on, which made us confident we weren't going to get hit by a plane landing, because there's no way they would have been able to even SEE the runway if they had wanted to. Once at the end of the runway, I turned around, stopped, planted my left foot on the brake and floored the gas with my right. I was expecting a reasonable screech of burned rubber followed by not-unreasonable acceleration. I was given the merest hint of a chirped tire and followed by acceleration that would hardly make an '82 Civic hatchback jealous. I nearly drove off the road (er, runway) from laughing so hard. Note to self: Next time, get the Impala.

When we got back to the high bay, FIREBall was out of our way so we started setting up our work area. We worked on this until about 10 PM and then left for the night...at which point it had started snowing. We can't even escape the snow in New Mexico.

Today's picture album:
http://picasaweb.google.com/asad137/EBEXInNewMexico32609#