H2 Splitting Tests
The last week has been extremely interesting around HUG. Last Monday, we saw our first hint that Platinum is preferentially recombining something. We were finishing up our last couple calibration runs with a commercial oxide coated constantan wire in H2 when we saw that the first run looked way different than the second run. Note how the pressure (green line) drops during the first step up cycle, but not the second one. And then, the resistance drops at higher temperatures - more so in the first one than the second.
When I looked closely at the difference between the runs, I saw something very cool in the Platinum temperature and the Silver temperature. (Note: T_Cu is actually a silver wrapped thermocouple, now, because we are told that silver is less catalytic than the copper.)
While the Wire temps and the Silver temps were extremely similar between the runs, the Platinum temperature was different between the first and second runs. How different?
About this different! It's not many degrees, but the temperature where it varies the most is also the temperature at which the pressure in the cell was dropping!
So, what would cause the platinum to be hotter and the pressure to drop? Was this commercial constantan splitting H2? Was it making water that was interacting mildly, but preferentially with the platinum? (See lab notebook here for full details)
Well, it just so happens that our new RGA (on loan from Nikita Alexandrov), was just about ready to test, so we slowly vacuumed down the cell through the RGA.
Here is the compiled video made from the scan data (a 2 day effort to write scripts to process data files).
The basic conclusion that we can come to is that there was quite a bit of water. We are newbies, though, and would welcome second opinions and observations.
Our current hypothesis is that H2 was reducing the MgO coating on the wire and making water. Some of the H and O flew loose and combined on the platinum. There should be no pressure drop from H2 + O (in MgO coating) => H20, at least till the H20 started condensing on the cold part of the cell. We believe it is likely we saw this water coming out of the cell in the RGA scans.
(See lab notebook here for full details)
New Test Cell for Gamma Detection
We have a new cell optimized for getting test wires close to our NaI gamma detector.
In practice, it looks like this when mounted along with the gamma detector just above it.
Next Steps: Combine Gamma Detection with H2 Splitting test
Our immediate plan is to test the new cell with a control wire and then install our last remaining Celani wire. We will load it with Hydrogen while watching the pressure and watching for gamma rays. Then, we will transfer it to the other cell with the platinum and the silver wrapped thermocouples and test for H2 splitting. Stay tuned!