New Configuration

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Bob Reite
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New Configuration

Post by Bob Reite »

My bubble detector finally wore out. Since I'm pretty sure that I am going to be in this game awhile longer, I decided to get a neutron detector that won't go bad in nine months. I found a Eberline NRD9 REM ball on Ebay, along with a Eberline SRM-200 Radiation Monitor which will operate with the NRD9. The previous owner had written the optimum operating voltage on a label attached near the BNC connector, so all I had to do was set the high voltage on the SRM-200 and set the calibration factor for the NRD9 from the SRM-200 manual and I was good to go. Yes, I know it would be best to either recalibrate against a fresh bubble detector or send the units to a calibration lab but I still will be able to judge improvements with my system.
newcfg-2.jpg
The next change is to try a new system for accelerating ions. It is said that the primary loss mechanism in the Hirsch/Farnsworth fusor is the heating of the grid through ion bombardment. Ions that heat the grid are lost to the fusion process. So I decided to take out the grid and somehow make the plasma itself negatively charged. The question was how to "excite" it. I figured that I could get a "beam current" by putting two sharp electrodes in the vacuum chamber with a slight potential difference between the two. One connected to the nominal - 40 KV output of the CW multipler, the other tapped off at the second to last stage which would nominally put that electrode at - 35 KV. I first had the electrodes spaced about an inch apart and there was a lot of heating near the end of the longer electrode. I shortened them to give about a three inch gap. Now the majority of the heating seems to be in the plasma although the electrodes still do get hot as can be seen in the photo.
newcfg-1.jpg
Now the big questions!

First, does the SRM-200 electronics and REM ball respond to "garbage" from the fusor high voltage supply? I ran the system with air at 40 KV 5 ma and around 15 microns pressure and the SRM-200 showed a zero reading.

Second, does this configuration really make neutrons? I turned on the electrolysis unit and filled the chamber with deuterium. At about 30 KV the speaker on the SRM-200 started clicking every once in a while. I "walked in" the system and eventually got a 5 mREM/h reading from the SRM-200 at 5.0 sccm flow rate at 20 microns pressure, 40 KV 5 mA (the current is about half that of the grid system for the same drive level). The center of the REM ball is 26.67 cm from the center of the plasma. So let's see.... that gives 3.48 x 10^5 n/s isotropic.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
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Richard Hull
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Re: New Configuration

Post by Richard Hull »

Nice work Bob! You can actually get fusion real easy in any acceleratory gas discharge with a fusion fuel like deterium.

Jon Rosenstiel did a lot of work with odd electrodes several years ago and reported his work here. He got fusion at every turn.

The heating of the grid is never the issue related to fusion, it is the loses due to electron losses that kills fusor efficiency. Since there is at minimum a 8-9 order of magnitude loss differential a 10X or even a 100x improvement in fusion would not be a path to any sort of success beyond more neutrons for experiments, etc.

I still feel we are implanting Deuterium in the electrodes regardless of type and also feel a signifciant fraction of fusion can come from random beam-target interactions in addition to the recognized fast neutral-ion collisions.

The Rem ball when properly adjusted and all cabling properly shielded is fairly noise immune. I think you proved that with your null test.
Remember, once you get the environment right, fusion is very easy to do.

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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Nick Peskosky
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Re: New Configuration

Post by Nick Peskosky »

What type of metal/alloy are the electrodes made from and do you have any images showing how the HV feed-throughs are mounted on your chamber?
Nick Peskosky
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"The whole of science is nothing more than the refinement of everyday thinking." - Albert Einstein
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Bob Reite
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Re: New Configuration

Post by Bob Reite »

The top electrode is stainless steel, it is the one originally supplied with the feed through sharpened to a point. The bottom one was tungsten. I say "was" because it was too small and eventually melted anyway, so for the last run it was actually a stub of 14 ga copper wire which was the material that the bottom feed through was supplied with. I may reinstall the grid that I used to quality for the neutron club and run the same pressure, flow rate, current and voltage and compare the REM ball readings against what I had from the bubble detector. I'll search for Jon Rosenstiel's work and take more photos the next time I dismantle the chamber
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
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Bob Reite
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Joined: Sun Aug 25, 2013 9:03 pm
Real name: Bob Reite
Location: Wilkes Barre/Scranton area

Re: New Configuration

Post by Bob Reite »

I also tried this configuration with both electrodes at the same potential, and the fusion rate was the same as with the 35-40 KV design. I since have reinstalled the "conventional" grid and I'm getting the same neutron emission, around 350,000 n/sec. Not sure why I'm not able to get back to the 500,000 n/s mark I had in earlier experiments, even after a few days of "breaking in" after the configuration changes.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
William_Estlick
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Re: New Configuration

Post by William_Estlick »

Is this the electrode configuration the same as the one you where running?

https://www.youtube.com/watch?v=tl_4Nc4-IX4
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Richard Hull
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Re: New Configuration

Post by Richard Hull »

I will not answer for Bob. However, his system and instrumentation is known to be superlative and his synopsis of his efforts thorough and trustworthy due to his past efforts. This means that regardless of methodolgy, he is on top of his game. We might now await his response.

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
User avatar
Bob Reite
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Joined: Sun Aug 25, 2013 9:03 pm
Real name: Bob Reite
Location: Wilkes Barre/Scranton area

Re: New Configuration

Post by Bob Reite »

Similar but not the same. I do not have the third electrode at positive potential, just the grounded vacuum chamber. As you can see from the measurements I did, the neutron output from the "pillar of fire" arrangement was statistically no better nor worse than a "standard" fusor arrangement.

For those that are wondering where I am in my fusor development, it has taken a back seat to my "day job" which is keeping me quite busy. The good news is that with the revenue from the "day job" I will be soon be able to purchase the parts to build my next configuration.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
William_Estlick
Posts: 99
Joined: Fri May 22, 2015 4:47 pm
Real name: William_Estlick_Sr.
Location: Cape Cod, MA

Re: New Configuration

Post by William_Estlick »

Time and or money always seems to be the limiting factor.
I am planning on obtaining deuterium and detector (as soon as money permits).
But if you or anyone else is willing to try this configuration in there chamber, I may be of assistance.
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