Physics in Progress

80s sampling scope with touch screen CRT. It can see you finger about a cm away from the screen. This scope can take one sample every 10 ps as long as you have a repetitive signal. That's pretty fucking fast.

Debugging via unlabeled array of lights.

Another failed jet attempt.

Sunset in the work parking lot.

:(

My incoming daughter's stuffed resistor and capacitor.

FYI IceCube is a neutrino detection experiment at the south pole. Basically they put cameras on strings in the ice, then wait for neutrinos to cause a flash.  Neutrinos don't interact very often, so your detector needs to be really big, and fairly clear, so that when they do interact you can see the flash.  Some people use giant swimming pools, others use ice they found lying around at the south pole. I'm reading a paper about how to drill holes faster, so they can put even more cameras in the ice.

Found this during "lab clean up". I almost threw it away, but I realized this is part of my science heritage from before I started working here. Let me see if I can explain what you're looking at. Start at the bottom and look at the reflective squares. Those are silicon chips made in the clean room with a few layers of patterned aluminum to create a tunnel junction refrigerator (basically what I did my phd work on). The refrigerator only works when the aluminum is superconducting, so it need to be at sub-Kelivin temperature, so this whole thing will be bolted into a cryostat. Now look at the first grey horizontal part, and look for the sets of 6 copper colored leads. This is to make electrical connection to the refrigerators with wire bonds. For these devices we typically measure IV curves, which just means you set the current, measure the voltage, and repeat. Next up is another horizontal grey piece. You can see a row of gold colored holes on both grey pieces. I think this was used to route and reroute electrical signals by putting a wire one upper circle and one lower circle. Next up is a bent brown sheet. This is a thin insulator with copper on the back, and copper traces on the front. I think it was for heat sinking. You know how even if your house is 80 degrees, water from outside can still be cold? This is the same idea, even though the whole platform is at .1 Kelvin, the electrons coming down the wires can still be way hotter, this is an attempt to cool them down before they get to the sensitive device being measured. Finally the thing in the top right is a connector. It just connects to a bundle of wires in the cryostat that are accessible at room temperature. Our sample boxes look way nicer these days, they're easier to use. But basically they have the same goal as this.

We just tried doing an xray emission measurement for the first time. On the right is an xray optic that focuses X-rays onto a sample in the middle. In this case the sample is a piece of iron foil. On the left is our xray camera. It's sort of subtle but the camera is not directly in line with the xray optic. So we won't catch any X-rays that just go through the sample. Instead when the sample absorbs an xray it is very likely to quickly emit another xray in a random direction. We're looking for those emitted X-rays. It's important to be as close to the same as possible to catch as many of the emitted X-rays as possible.

Small tube + grinding stone. I ended up using pliers to hold the part, since this picture looks like a recipe for injury. I needed a 1cm or shorter piece of small steel tube. I didn't have the right tool to cut it so I used wire cutters, but they crimp the end closed. So then I ground off the crimped part.