Research Update June 7

This morning the ion gauge read ~8.3x10^-8 T which seemed like a really good sign. Anyways, I started up the ion pump with the chamber cold on the gamble that I wouldn’t have to heat the whole thing up again. The burp took the pressure up to 10^-4 T and then eventually settled at 1x10^-8 T on the pump and 1.28x10^-7 T with the gate valve open again. I rattled around pretty good on the back of the pump after I started it.

I’m not sure why the discrepancy between the pump and the gauge. For the life of the chamber the pump has always read about a factor of 2 below the ion gauge. I don’t know why it’s a whole decade now. I decided that this was good enough though and that I didn’t need to heat up the whole chamber again.

I spent the better part of the day restoring the MOT chamber to it’s operational status and a significant part of the day trying to take a picture of the stupid doubling cavity. I was trying to use dry ice and water to create a vapor that the beams could diffract off of, however, the filters in the camera are really high quality and there is almost zero sensitivity to IR photons. The best I could do was get a picture showing the blue beams.

When I was on the oven for the chamber I tightened the bolts on the nozzle flange up to torque (they were loose too). I needed to get the bronze slug around the oven off in order to install the slowing coils. However, one of the bolts on the thing had frozen and I had to drill it out. Very frustrating. After I put the coils on I installed the oven slug held together solely by the oven heater. I also matched the nozzle and back heaters so that they heat together in parallel and not unevenly.

I wanted to get a high quality picture of fluorescence in the MOT, but the laser was being a real pain the but tonight. I spent the time while things were heating up to clean some of the lab and then align the beam, but by the time things were hot the laser was not cooperating. I think I’m going to have to reoptimize the wavelength. It seems to have drifted and now wants to lase quite a bit up in wave number. blah.

I also think I shot myself in the foot with the picture, because I had aligned the slower beam straight down the nozzle. I could see light fluorescing off the side of one of the windows but I could never see a beam in the center of the chamber with 3 laser beams intersecting through it.  I’ve been thinking about it and I think the slower beam was blasting the atoms back into the oven  on resonance and I was watching the reflection off the front of the oven flash on and off with the atoms. When it was on resonance there were no atoms left to fluoresce off the other beams. I can check that out tomorrow.