Joe Gayo's Fusor

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Joe Gayo
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Joe Gayo's Fusor

Post by Joe Gayo »

Pressure: 25mTorr (4mTorr base)
Voltage: 40kV (50kohm ballast resistor)
Current: 6mA

Detector: CHM-11 (1600V, 64x Gain, 3V Threshold)
Run CPM: 622 (Avg 5 min run)
Background CPM: 2 (Avg 30 min)
IMG_0811_sm.jpg
IMG_0810_sm.jpg
IMG_0871_sm.jpg
IMG_0806_sm.jpg
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Joe Gayo
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Re: Joe Gayo's Fusor

Post by Joe Gayo »

CHM-11 Tube Adapter Box

HV Input w/ RC Filter (2Meg * 47nF)

Bias w/ 50Meg

AC Couple w/ 33pF
IMG_0800_sm.jpg
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Richard Hull
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Re: Joe Gayo's Fusor

Post by Richard Hull »

Nice. Can't wait to see those bubbles.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Cristiano_Machado
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Re: Joe Gayo's Fusor

Post by Cristiano_Machado »

Congratulations! It is a very nice and compact setup.
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Joe Gayo
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Re: Joe Gayo's Fusor

Post by Joe Gayo »

Thanks.

4-6 weeks will be a long wait for the bubble dosimeter, but worth it.
Ameen Aydan
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Re: Joe Gayo's Fusor

Post by Ameen Aydan »

Really nice setup man! You must have worked hard and long. I'm sure if you live close to a large city that there are calibration services or people on this form who are willing to calibrate with you. Good luck on your efforts, but judging how well this system is, I don't think your going to need it.

Ameen Aydan
Cristiano_Machado
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Re: Joe Gayo's Fusor

Post by Cristiano_Machado »

Do you really need a BD? I know it is a positive proof, but I believe (I am not an expert) you can already claim that you produced neutrons in a fusor, and be part of the Neutron Club.
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Joe Gayo
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Re: Joe Gayo's Fusor

Post by Joe Gayo »

I would rather wait until my setup is calibrated. I have a high degree of confidence that neutrons are being generated but an exact quantity (+/-20%) is more satisfying. In addition, I’m improving the signal processing of the neutron pulse in the meantime.
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Richard Hull
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Re: Joe Gayo's Fusor

Post by Richard Hull »

We, in the past have seen the Russian tubes mis-used, mis-calibrated and regularly detect the x-radiation from a fusor operating at 35kv and above.
The BD doesn't respond to X-rays at all, nor does a well worked, high pressure 3He tube or BF3 tube.

Boron lined tubes can also detect x-rays. Too many of the applicants have zero experience with electronics. Those who are proficient in electronics often have no experience with nuclear instrumentation. Those who do have a passing experience in nuclear detection electronics seem to have never constructed, worked on and tested a good, reliable neutron detection system.

The very fact we never get the classic test right out of the chute by electronic detection claimants explains a lot about their competence in neutron metrology. This gives rather constant pause to such first pass claims. We have explained this test over and over again but to no avail. It seems to zip right over the heads of all claimants.

I fear many do not read at all or to not read for comprehension or just read, understand and refuse to deliver. One of the great mysteries here.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Joe Gayo
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Re: Joe Gayo's Fusor

Post by Joe Gayo »

Richard,

I assume you are talking about tests with and without the moderator, then with and without deuterium in order to eliminate x-rays and electronic noise respectively.
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Richard Hull
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Re: Joe Gayo's Fusor

Post by Richard Hull »

No! I am talking about two full and complete fusion runs as close to identical as possible. Same voltage, current and D2 pressure, (as close as possible), and the exact same run times. The only difference being is that one run is made with moderator and tube together as a neutron measuring run and the other full fusion run with the moderator removed to some distance and just the naked tube doing the counting at the exact distance from the fusor as in the run with the moderator and tube.

I hate having to keep reiterating all of this. This is to see if you are really counting neutrons.

Check out the dramatic example - the second Tuesday follow up run.

viewtopic.php?f=18&t=7893

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Joe Gayo
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Re: Joe Gayo's Fusor

Post by Joe Gayo »

I think we said the same thing ... with and without the moderator ...

I was proposing an additional test without Deuterium but thinking about it, that isn’t valuable

And if you are a forum moderator for 18 years, you will probably repeat yourself a lot
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Richard Hull
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Re: Joe Gayo's Fusor

Post by Richard Hull »

The only real value in an air, nitrogen or argon test, (no deuterium - tube in or out of moderator), is if you get many counts, you have a nice x-ray detector and not a neutron counter.

However, if you have already run deuterium over time, some D is buried in the shell and you will get some limited fusion as they exit the shell walls under bombardment in an air run.

It is best to just do a couple of tube-in / tube out runs. We don't really need CPM values, just gross counts as both runs are of the exact same time frame.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Joe Gayo
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Re: Joe Gayo's Fusor

Post by Joe Gayo »

I've done this test before but I re-ran this morning (detector in same relative position to fusor for all tests, 10cm) -

30 minute background with moderator: 24 counts

No moderator / No activation oven (within 3m):
28 mTorr D2
35kV @ 10mA
90 seconds, 274 counts
(note: pulse has leading negative component and positive amplitude prohibits discrimination ... windowing might work)

Moderator:
28 mTorr D2
35kV @ 10mA
90 seconds, 2506 counts
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Joe Gayo
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Re: Joe Gayo's Fusor

Post by Joe Gayo »

Based on looking at the pulse waveform from the amplifier with an oscilloscope I was able to setup a window discriminator (2.1-5.9V) to reject the majority of events that occur without a moderator. It does appear that most non-moderator events have a leading negative voltage spike and a subsequent >6.5V event.

29 mTorr D2
32kV @ 12mA
90 sec without moderator: 3 counts
90 sec with moderator: 291 counts
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Dennis P Brown
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Re: Joe Gayo's Fusor

Post by Dennis P Brown »

Nice work. Your detector system has a good bit of noise. I enclosed my neutron detector tube in a copper tube, electrically sealed both ends and had almost zero noise issues; however, rejection works as well. I'd like to see your activation results if it isn't too much extra work (and not needed - your current results are good) - Ag activation really shows you have a high neutron flux.
Cristiano_Machado
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Re: Joe Gayo's Fusor

Post by Cristiano_Machado »

Dear Mr Brown,

Sorry for my ignorance, but how do you "electrically seal" a tube? I would like to test this on my detector.

Thanks,

Cristiano
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Dennis P Brown
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Re: Joe Gayo's Fusor

Post by Dennis P Brown »

I solder two copper end caps on the copper tube (the neutron detector is inside. I placed some electrical tape around both ends of the detector tube a such that it (the tube) makes a semi tight fit inside. Don't want it moving around.) One end has a proper co-axial connector fitted to the cap. The inside is connected to the neutron detector and the outer one gets your detector coaxial cable. Works extremely well.
Cristiano_Machado
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Re: Joe Gayo's Fusor

Post by Cristiano_Machado »

Thank you for the instructions. I will test that!
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Joe Gayo
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Re: Joe Gayo's Fusor

Post by Joe Gayo »

I think it's x-ray detection not noise.
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Richard Hull
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Re: Joe Gayo's Fusor

Post by Richard Hull »

I see you have an 3He tube no worry with x-rays, typically. Just bias it well and do a good job on electronic windowing.
Re-run tube in vs. tube out
Never wrap or solder anything to a valuable and expensive 3He tube!!

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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