S.T.A.R. Run #3

[Steven Sesselmann]

Hi guys,

After a whole run of problems, my reactor is back up and running.

Had to get another turbo pump controller from the US, and the local glass blower had to make new accelerator tubes for the reactor after the old ones gradually became conductive on the inside, due to sputtering from the copper electrodes in the ion gun.

This time I have assembled the ion gun with ceramic cotton stuffed into the head containing the copper electrodes, which I hope will prevent the copper ions from making their way into the reactor core.

Last night, after putting her back together, I did a few quick fusion runs, and she is behaving nicely.

Step 1.
The turbo pump running on economy speed, the chamber pumps down well below 1 micron.

Step 2
Ion gun filament heating set to 4 volts (orange glow) and filament bias set to -1000 volts.

Step 3
He3 and B10 neutron detectors switched on and counting

Step 4
Video camera running and recording

Step 5
High voltage switched on, and slowly ramped up to 45,000 volts. Amp meter indicates no current at full vacuum.

Step 6
Deuterium bleed valve slowly opened, allowing deuterium into the reactor through the ion gun. The video monitor indicates purple plasma can bee seen coming from the ion gun, and a smooth glow can be seen coming from within the cathode. After a few seconds, instabilities cause the plasma to start flashing and pulsing. Gentle adjustment to the gas flow setting the pressure between 40-50 micron settles it back down.

Current fluctuating around 3 milliamp sometimes hitting 5 milliamp.

There is definitely a sweet spot on the throttle, where all the neutrons are produced, I can see this from both neutron counters.

This run lasted about 2 minutes, and the detectors were 25 cm from the reactor core.

The He3 neutron counter clocked up a total 6500 counts (8.4 cps/nv)

The B10 survey meter, placed at the same distance was fluctuating between 0 and 3 millirem.

The total output over the two minute period is not impressive, but keep in mind that higher levels of neutrons were produced at specific intervals.

View the run at : http://www.youtube.com/user/beeresearch

Note:
The S.T.A.R. reactor is designed to to have the anode cathode inter-space filled with dielectric oil. This will have several positive effects, firstly the voltage can be decreased to -100 kv or more, secondly it will have a cooling effect on the cathode and glass tubes, last but not least, the dielectric oil will moderate and reflect a significant number of thermal neutrons back into the cathode. Thermal neutrons in the core will further enhance the reaction rate.

I need to be 100% sure that the vacuum connections around the cathode and accellerator tubes are hermetic, before filling up the reactor with oil, or else it will make a helluva mess.

Comments and suggestions welcome as always..

PS: Who is going to be the first to build a S.T.A.R. reactor in the US ?

Steven

[Donald McKinley]

Steven,

I think you have a simple cleaning job with your glassware. I think I would wash out the sputtered glass tubes with concentrated nitric acid. That will take care of the copper and I would imagine dislodge any carbon based conductivity. It dissolves copper immediately, and the acid is cheap if you buy the technical grade. (Does an incredible job on the dishes too.) Don't dunk actual solid copper unless you are prepared for the NOx which is noxious and aggressively damaging to lung tissue. Causes delayed terminal edema.

Don't buy too much at a time. It's dangerous to have too much if you're not set up for storage and don't use it often. Don't buy more than 8 oz for what you're doing if you can help it. Use eye protection and all other appropriate safety measures of course.

A safer and cheaper but more time consuming process. Straight kitchen 6% distilled vinegar will dissolve steel wool over time & so I would imagine it would dissolve copper as well (forming copper acetate) although it doesn't happen very fast. Some of these reactions have an induction period which can be short circuited by adding a little of the salt in question (iron or copper acetate) to the solution.

Don.

[Steven Sesselmann]

Don, thanks for the advise, it's worth trying..

On other matters, when I study the video from run 3 carefully, I notice when viewing the video frame by frame, that the appearance of random bright pixel dots appear, and occasionally they appear like long tracks with a bright spot at the end. These are not permanent dead pixels, but pixels on the CCD device which are being triggered.

There are virtually no sparkling pixels at the beginning and middle, only from about the 2/3 mark.

Could these be neutrons, or will gammas and x-rays produce the same effect?

Has anyone noticed a similar sparkle?

Steven

[Nanos]

What do you have as shielding between the CCD and the source ?

Lead glass ?

[Richard Hull]

Sparkle in a CCD is usually an electrical noise indicator. Blown pixels are a sign of nuclear damage.

I notice in the image the pulsing purple glow. When a fusor is in a neutron/fusing mode, every thing in the core is a rich red. The deeper and richer the red the more fuel you have working for you. Purple is, classically, an air related color.

I think the ultimate proof of the pudding will be bubs in the BTI detector once yours arrives. This device is now the defacto standard heralding FAST neutrons. Note, that if you "oil up" and make the neutrons emitted from the device epithermal or thermal, the BTI will NOT detect those neutrons.

I have tried to corner the BTI guys on what is fast and they tend to want to say over 1mev, but did note that it will see lower energy neuts but have fewer bubs than rated or "binned".

So, if you start whimpying up you neuts in oil, your BTI will not report correctly, if at all.

Richard Hull

[Steven Sesselmann]

Nanos, The camera is around 3 meters away from the source, it has a telephoto lens, and there is no shielding between the camera and the source.

Richard,
Yes, the BTI detectors should be here next week, so I will keep the system without oil for the moment. I am still happy under 45 KV.

At the moment I am trying to understand the theory behind a plasma confined inside a hollow cathode. There are some interesting interactions between the inside wall of the cathode and the hot plasma, which I really need to understand.

I hope to celebrate with bubbles on new years eve

Steven

[Mike Beauford]

I'm keeping my fingers crossed for you Steve. Good luck!

[Starfire]

I hope to celebrate without bubbles on new years eve ( Hogmanay ) in Edinburgh - I will probably be the only one without bubbles