Fusor Forums

Remember the key to it all related to neutron counts! You need make two equal timed readings....One with tube in moderator and then the tube out of moderator. Voltages and currents have to be proper for the count noted. 16 kv will not do much detectable fusion.

Richard Hull

But wait. I was not using the tube on this test. I was using a bubble dosimeter. And I also wasn't using 16kv, I was using 32.

Your results look promising, but I would recommend organizing your data for clarity's sake.

Voltage:
Current:
Deuterium pressure:
Bubble dosimeter sensitivity:
Bubble dosimeter distance from ideal neutron source:
Bubbles generated:
Combined duration of testing:

Also, you should include a photo of the fusion plasma in your report. I would recommend trying to calculate your isotropic neutron emission rate. You said that you intend to operate your fusor soon. Keep all values as consistent as possible and document everything you can. Your evidence should be able to prove fusion beyond a reasonable doubt.

-Kuba

Kuba is correct. Good data presentation in an orderly fashion is a must. Those of us how have done fusion....know fusion in a way that allows critical review. Critical review demands organized, critical and precise data collection and reporting and not a scatter of numbers blasted out on a page.

With a flawless operational 3He counter the ultimate test is the two count method. One count with the tube in moderator and another with the tube outside the moderator.

The 2 micron level is unbelievably low for a D2 pressure, but experience shows that at the rather high voltage and current you claim, minimal fusion is possible. I find it amazing that you attained a glow at those levels.

Try a good report and fill in these blanks

operational data:

1. period of operation from zero counts or zero bubbles to final count or final bubble talley.
2. average voltage of operation over above time span.
3. average current of operation over time span.
4. average deuterium pressure over time span
5. image of fusor grid taken during the run.
6. if using a counter. 1. 10 minute total background count 2. count with tube in moderator over a stated operational time and 3. another count with tube out of the moderator during operation over same period as #2 count.
7. images of the bubble dosimeter before and after count if such a device is used.

Overall, you have shown most of this over a vast number of postings. Try and do all of this in one single polished report posting.

Note data accumulated over 8 runs is not allowed. fitful starts and stops are not allowed. A single run may not be stable but should be continuous. It is from a single run that the data should be submitted. Do not submit a photo from a pretty photo run and voltage and current data from another run, pressure from another or a total bubble count from three consecutive runs.

For us, you must show that a normal run of your fusor has a good average voltage of X and a current of Y and a pressure of Z and a bubble count and all data taken of a single time period of T.

All fo this is spelled out in a FAQ on how to report for inclusion in claiming fusion.

viewtopic.php?f=24&t=3134&p=12644#p12644

Thanks

Richard Hull

The anomalous pressure reading is due to inaccuracies in your equipment. Like you, I used a CPS VG200 vacuum gauge for my fusor. After pumping with only the mechanical pump, the gauge read 0 microns. My mech pump is rated at an ultimate pressure of 12 microns. When that gauge reads 0 microns, the real pressure is likely around 15 microns. If you want an accurate pressure measurement, get a proper tc or ion gauge. The CPS gauge is meant for automotive work, not fusion reactors. I ended up using the CPS gauge anyway and simply used the generated voltage as a more accurate guide for the pressure in the chamber.

-Kuba

Many fusion folks, over time, learn how to tell their instruments are lying or have gone astray. Much like Kuba points out, looking at the glow and looking at the applied voltage and current can really tell an advanced or advaning user that his or her vacuum reading is crap and force them to check their vacuum gauge for calibration or failure. The true newbie is at the mercy of poor instrumentation in many instances and will have to go to the school of hard-knocks before picking a lot of this up. One cannot over-emphasize the need for at least a TC gauge in the foreline. (Sadly, even this gauge can be off a bit at the extreme low end, but is is better than a poke in the eye with a sharp stick and 50,000% better than a junky refrigeration gauge.)

Richard Hull

I think I've got it all now:
1. 12 minute operation
2. 35kV average voltage
3. 24mA average current
4. 5-15 micron pressure (on my gauge)
5. I attached pictures of grid. Most of the time it was in the golden state.
6. I attached dosimeter images. (the bubbles are only in the top because my dosimeter slipped sideways during the test, aiming the top into the chamber at an angle, but it was under my lead shielding so I didn't notice.)
7. Dosimeter sensitivity: 73 bubbles per mrem
8. 6 inch dosimeter distance from neutron source
9. The bubbles cannot be counted because they formed a foam.
10. My x ray counts averaged around 40k cpm, with some moments over 70.
11. I added some pictures of the test setup.

Zan,

I like the way you presented your data however, I am slightly concerned about your BTI measurements. I am not an expert on Bubble dosimeters but those bubbles near the top do not appear as uniform and concise as they usually are/should be. Perhaps the quality of the image low. Did the BTI ever make contact with the chamber itself? During operation the chamber's temperature can rise significantly. The bti is sensitive to high temperature and can result in false bubbles. I have attached an image below of Bubbles I saw when I ran my fusor.


Also, regardless of the angle of the BTI, you would anticipate a relatively uniform distribution of bubbles in the BTI (generally speaking as the neutrons are emitted isotropically from the fusor.

Best of luck to you.

Scott Moroch

Scott is correct. Rerun. We need to see formal bubble production that are clean and clear. 70 or more bubble per mrem is a very sensitive BTI! Those images do not resemble real fusion, either. Those in the know here, know. Sorry to be such a stickler, but proof is proof and we need it.

I attach images of my setup when I used the BTI and a black and white image of real-time fusion from my video camera on the monitor screen.

Note** the BTI is very sensitive to heat! Mount it where vertical convection heat from the fusor cannot warm it!

Richard Hull

Okay, I've got a rerun.
1. 10 minute operation.
2. 24-35kV voltage. (lots of variance, mainly in the mid 20kV's)
3. 40 to 60 mA (I actually blew my variac's fuse at the end).
4. 10 micron pressure
5. Grid picture attached.
6. Dosimeter pictures attached.
7. 73 b/mrem sensitivity
8. 8 inch dosimeter distance from ideal neutron source.
9. 7 bubbles
10. Really high x ray counts, in the couple hundred k cpm. I attached an image actually.

Zan, I have added your name to the fusioneers listing. Good going.

Richard Hull

Hooray for Zan!

I think the very last round was critical.
As others have said, your previous-round bubble pictures didn't match the familiar signature of neutron doses.

I bet they show us the signature of detector gel getting too hot in a small region. Fortunately it was reversible, or you had a spare detector. The scientist in me would try to reproduce that effect, by local heating in the absence of a fusor. That would be analogous with Roentgen or Becquerel steering off track to investigate unexpected glows or photo-plate fogging.

Thank you everyone for everything. I have been looking forward to this for a long time. But this is nowhere near the end of my fusor endeavors. I'm looking forward to more progress in the future (chamber upgrades, grid upgrades, new gauge, calibrate my 3He tube, and ion guns!). I'm thinking about taking a break now though, and maybe trying to build a Van de Graaf just for fun.

PS: And also, my bubbles have grown, and some smaller ones are now visible, so my new count is 11.

Thanks again,

Zan

Congratulations on the neutron club Zan! I've been watching this thread from the start, and your setup and persistence is inspiring.

Excellent work - congratulations.

Thank you!