We got the butterfly value installed and tested out the new grid. Beautiful stable plasmas. Air plasma:
Deuterium plasma in star mode:
No bubbles yet. This video shows the stable air plasma:
Star Mode
Posted in Deuterium, Fusor, Plasma, Vacuum, Welding on November 3, 2009 by FAMULUSNew Inner Grid
Posted in Fabrication, Fusor on October 27, 2009 by FAMULUSYesterday I made a new fusor grid:
With an 45mm OD, this grid is smaller (and prettier) than the previous at 65mm. The old and the new grid side by side:
Second Attempt
Posted in Deuterium, Fusor, Neutron Detection on October 25, 2009 by FAMULUSMade a second fusion attempt today with a deuterium plasma. Using the new power supply and the mass flow controller together produced very stable plasmas. I tried a variety of voltages, currents, and pressures but no bubbles.
I have two hypotheses:
a) we are producing fusion, but the detector is not showing it.
b) we are not producing fusion because of grid misalignment.
While double checking the bubble detector, I noticed a relevant detail: the bubble detector must operate within 20˚ C to 40˚C. Today the room temperature was 16˚C. The detector has a built in liquid crystal thermometer. Black means the detector is out of range. To correct this, I put the detector in my pocket for 20 minutes. This warmed the detector to 34˚C :
I want to get a geiger counter as a double check for the bubble detector. The geiger counter would respond to x-rays produced during fusion.
But really I think the problem is that our inner and outer grids are completely misaligned. From what I’ve read grid alignment is necessary for “star mode”. And it seems this is necessary for fusion.
It should be pretty easy to fabricate a new/better pair of grids.
Although we didn’t get fusion today, it was a success in other ways. The system is working smoothly. We have stable plasmas with voltages as high as -17kV. The mass flow controller minimized the deuterium use.
The mass flow controller also lets me adjust the gas flow at a safe distance, which is a welcome upgrade.
Here is a video of the deuterium plasma:
-30kV / 10mA
Posted in Fusor, High Voltage, Plasma on October 24, 2009 by FAMULUSIf you’ve been following me on twitter, you know I received a -30kV / 10mA Glassman a few days ago. Now it’s online and it kicks ass. Current limiting, remote controllable… it’s the second unit from the top:
Here is an air plasma it produced:
With current limiting and good air metering, we can get a stable plasma. I notice you get a sense for the plasma just by _listening_ to the glassman. When the plasma is unstable the glassman softly clicks along with the plasma burst.
Mass Flow Controller Online
Posted in Deuterium, Electronics, Mass Flow Controller on October 21, 2009 by FAMULUS
Cleanup
Posted in Uncategorized on October 19, 2009 by FAMULUSWith the large chamber gone, I’m able to setup properly:
As the project gets complex, I must keep the lab organized.
Superconducting Magnet
Posted in Magnets, coils, heater barrel, superconductors on October 15, 2009 by FAMULUSGearing up for a second superconducting magnet test. This time computer controlled. Here is the new bobbin with 133 turns:
RGA
Posted in Residual Gas Analyzer, Vacuum on October 14, 2009 by FAMULUSTook another crack at the RGA. Got a lot further this time.
Previously we used the sensor in the flange it shipped in, but this flange did not hold a vacuum. I removed the sensor:
And reinstalled it like this:
More after the jump.
Phreaknic 13
Posted in Community, Hacker on October 14, 2009 by FAMULUSI’m speaking at Phreaknic 13!
October 30-31, 2009 in Nashville TN.
Talking about amateur nuclear fusion and prometheus fusion perfection.
