Copasetic Flow

I was back in the lab this morning.  I’m working on getting the four point measurement to work on the YBCO sample.  In the grand scheme of things, this is low priority, but it’s important to know that we can successfully make these measurements here before we have a large bucket of liquid helium evaporating with a sample inside.  Here’s what the four point probe measurement looked like: There are still no conclusive results.  With any luck this is a consequence of me not being able to interpret the results more than a bad experimental setup.  The table below details the four point probe readings in ohms as the superconductor cools Table of four point readings Time Resistance kohm Comments 0 -0.35444 Negative reading is probably from swapped sense wires. 16 -0.36735 Immediately after nitrogen pour 59 -0.34466 Near minimum 101 ...

Lab Book 2014_05_09     Hamilton Carter                Summary Most of today was spent researching and planning what tasks needed to be done and when.   The only lab work was measuring the more of the dimensions of the fiberglass Dewar and checking on a source for replacement Dewars.  If we’re able to use YBCO, (a type of high temperature superconductor), to prototype the experiment with liquid nitrogen I spent some time determining how the low energy x-rays, (H-rays), could be detected.  One of the possibilities is just to use x-ray film as a type of integrating detector over several runs.  Another possibility s to setup the NaI detector to detect a lower energy spectrum.  The NaI avenue may be blocked to us because of the thickness of the permanent metal window installed around the NaI crystal. On the theoretical side of things, I spent some time making...