2014B Day 13: Settling In

It’s day 13 – we’ve been here almost 2 weeks out of 6 now – so we’re almost a third of the way through. I think of it like running a 5k (3.1 miles) where the first mile is the phase where you try to get out ahead of the pack, and the second mile is where you settle in to your pace. That’s where we are now, we’re settling in. Here’s a little bit about what that looks like.

Jared is starting up at the beginning of the night.

I’ve been monitoring the temperatures on Clio. Last week we hooked up the new pump, which is stronger than the old pump, and I was worried that the temperature wasn’t settling quickly enough.

Clio temperature monitor, plotted as a function of # of hours since we started cool-down this run. Top: The temperature of the Clio optics in Kelvin (77 K). Center: The temperature of the Clio detector in K. Bottom: The percent the heater is turned on. Each spike in temperature of the detector is when the Clio dewars are filled with 77-K liquid nitrogen, which melts the solid nitrogen and warms it up. Then the pump starts pumping away and lowers the pressure so that the nitrogen freezes and solidifies. The temperature keeps dropping, but we want to keep it stable, so when the temperature drops below the set point (53.3 K), the heater engages and tries to keep it at a stable temperature.

But take a closer look at just the detector temperature. I don’t think it’s quite as stable as it could be. I will think about this some more and possibly throttle the pump, crank up the heater, or go back to the old pump.

Take a closer look at just the detector temperature (bottom plot here). It isn’t quite stabilizing at the tenth-of-a-Kelvin level. I have to examine the darks to see how much it affects us. Also, the new set-point means I had to adjust the bias voltage, which means there is going to be a new linearity correction this run. Stay tuned.

Finally, some LCO lifestyle pix as we are settling in:

Sunrise from the summit

Dos huevos fritos por favor con aguacate, oatmeal, and fresh-squeezed orange juice
Life at LCO – breakfast then bed (please do not disturb)

A great song: