Bubble Calculator

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Steven Sesselmann
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Bubble Calculator

Post by Steven Sesselmann »

This thread has been moved to:-

viewtopic.php?f=6&t=2826#p12336

...a more appropriate forum.

Steven
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Jon Rosenstiel
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Re: Bubble Calculator

Post by Jon Rosenstiel »

Hi Steven,

I made the following mods to your calculator:
1. Changed volts and amps to kV and Ma.
2. Added a category for bub detector sensitivity. (For instance, my BDPND temperature compensated bubble detector has a sensitivity of 38 bubs / mrem).
3. I see you used 1 mrem = 8.4 neutrons / sq cm / sec, I changed that to 7.8 n / sq cm / s, which is, as far as I know, the accepted value.
4. Changed the Q value number to scientific notation. (My eyes were crossing trying to count all of those zeros)!

The entries in the attached modified sheet are from my most recent record (for me, anyway) run.

Hopefully I didn’t screw-up your Excel sheet too badly.

Jon R
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Steven Sesselmann
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Re: Bubble Calculator

Post by Steven Sesselmann »

Jon,

That's all good, I am working on a javascript web page for this, and I already thought of including a field for the BTI calibration.

I may as well make the starting post on this thread into the official Q list.

Well done..

My best run so far was S.T.A.R.3-Run 5 which had the following result.

Cathode 60 Kv - 3 ma
Ion gun 100 W

Power input: 280 Watt
Neutron flux at detector: 3.25 e1 n/s/cm2
Neutrons isotropic 1.63 e5 n/s
Total D+D fusion reactions 3.27 e5 fusions/s

Proton energy (3.02 Mev) 4.93 e11 ev/s
Neutron energy (2.45 Mev) 4.00 e11 ev/s
Triton energy (1.01 Mev) 1.65 e11 ev/s
Alpha particle energy (0.82 Mev) 1.34 e11 ev/s

Total fusion power 1.19 e12 ev/s
Total fusion power (converted) 1.91 e-7 Watt/s

Q = Energy out vs. energy in 6.82 e-10 -
http://www.gammaspectacular.com - Gamma Spectrometry Systems
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Wilfried Heil
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Re: Bubble Calculator

Post by Wilfried Heil »

Seems to calculate what it is supposed to. I made some changes to the units where needed.

Q is fusion power/input power in absolute numbers, not in [%].

The fusor does generate some heat through fusion, so the output power/input power will always be > 1.
I think it is the fusion power that you are interested in.

The data reflects one of our runs that I've posted under efficiency tests at 50 KV, 2 mA and 11.2 mTorr on March 31, 2007. Fusor inner diameter is 84 mm and the grid consists of 4 loops with 32 mm diameter.

To make the comparisons useful, you also need to post the parameters (kV, mA, mTorr, maybe others like fusor diameter and grid type and diameter) under which the run was made. From this we can then estimate what the performance would have been under other conditions.

I hope this will help to sober those who think they can boost a fusor beyond breakeven with volleyball sized chambers and kilowatts of input power.
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Steven Sesselmann
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Re: Bubble Calculator

Post by Steven Sesselmann »

Thanks Wilfried,

List updated..

Others, please give me name of devices, and date of best run, plus any novel features or improvements that differs from the norm.

Steven
http://www.gammaspectacular.com - Gamma Spectrometry Systems
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Jon Rosenstiel
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Re: Bubble Calculator

Post by Jon Rosenstiel »

Steven,

A little more data to go with the Excel sheet I posted.

Device name: Std Hirsch-Fanrsworth fusor with no name.
Presssure: ~9.3 mTorr
Shell dia: 15 cm
Grid: 4-loop tungsten, diameter = 31 mm.
Date of run: 06/25/2007

Jon R
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Steven Sesselmann
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Re: Bubble Calculator

Post by Steven Sesselmann »

Thanks guys,

I have made the updates..

I suggest that we keep the list nice and compact, and that the detailed operating parameters be included down in the thread, as improved fusion runs are being reported.

Instead of attaching the spreadsheet every time, users can cust copy the data in the cells and paste it into a post.

I look forward to collecting more data...

PS: Jon and Wilfried.. I updated the spreadsheet on my first post with the latest, so to avoid confusion, maybe you could remove the interim ones.

Steven
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Wilfried Heil
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Re: Bubble Calculator

Post by Wilfried Heil »

Steven - such a collection is pretty useless and meaningless without the additional information on the operating conditions. You can easily get 20 different values from the same fusor.

This may look like some kind of competition to the casual and uninitiated, but in reality it only reflects the voltage at which the fusor was running.

What would be interesting to find are differences under the same operating conditions or at least under conditions that can be compared. For example, a large grid appears to be an advantage, because the ions travel a greater fraction of their path at high speed, inside of the grid. Likewise I would be interested in any performance differences related to the size of the fusor or the construction of the grid(s).
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Chris Bradley
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Re: Bubble Calculator

Post by Chris Bradley »

I think it's quite clear what Steve is aiming to present here, but on a matter of detail to ensure no-one looking in gets confused I think it's worth saying that 'Q' is a frequently used variable for [at least] three different functions in physics/chemistry and clarity may be needed here in case it gets compared with any other data outside the forum.

In nuclear/chemical terms it may be used as the absolute amount of energy liberated in a reaction (which would be clear if it carried a unit of energy such as Joules/MeV, etc.), but it may also be used as the ratio of total-energy-in to total-energy-out of a process and would be a dimensionless value >1 for exothermic processes (<1 for endothermic).

In this case I would suggest there is a confusion between these two uses of a 'traditional Q' variable.

To compound this issue here is also the use of the term 'efficiency', which has associated with it certain thermodynamic notions. If you run a reverse-cycle air-conditioner to generate heat, a good unit would have a Q >2.5 , that is, it will happily generate twice as much heat energy for you as energy you put in. But the temperature you get out of it is too low to then turn back into useful energy. It is 'waste heat' in terms of energy production, which the term 'efficiency' relates to. If you were to try to do so, you MUST end up with an efficiency <100% as each stage cannot exceed a 100% efficiency either (as no fuel is going in to add to the output). So 'Q' and efficiency are two different things. Just because someting has a Q of 10 doesn't necessarily mean it can produce a net power gain.

So the pedantic upshot is that it would be more correct to change 'efficiency' to the term 'energy gain factor', or similar, and that this gain is therefore dimensionless and a small fractional value as per Steve's spreadsheet. Whether it is appropriate to carry on using 'Q' as the variable is here-nor-there, as long as it is understood what it is.

[For completeness, the third general use is 'Q-factor' which is the product of the ratio of energy stored to power lost with the angular velocity of a cycling system, and is quite different to the above.]

If I am in error on any of these points, then please correct me!

best regards,

Chris MB.
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Re: Bubble Calculator

Post by Q »

official Q list...
heh, sorry guys, i couldn't resist... i had to add my own $0.02...
shall i be listed?

Q
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Steven Sesselmann
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Re: Bubble Calculator

Post by Steven Sesselmann »

Guys,

Firstly to Chris, I am happy to remove the term efficiency, as I agree it is a bit misplaced. My ignorant understanding of the letter Q, was that it was a substitute for Quotient, and therefore used as a term simply to state that one number is a Quotient.

Wilfried, creating a bit of competition is healthy, there have been plenty of scientific achievements that have been fast tracked, when different research groups competed on the same project. I agree that each post reported must be backed up with all the data from that run, and I think that should be in the reply post under my list. I could create a link on the list, to the data post.

Of course every fusor run will vary, but the guys who have built quality reactors get very consistent and repeatable results.

If you have data from several runs, you could run it through the calculator and find out which one has the highest quotient, it may not be the one that produced the most neutrons.

What we are interested in on this list, is the best design, that yields the most energy out for the lowest input.


Steven
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Jon Rosenstiel
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Re: Bubble Calculator

Post by Jon Rosenstiel »

Wilfried,

You’re correct, more detail would help, but I have to wonder just how much it would help? I think it’s still like comparing apples to oranges…each and every one of us has totally different setups.

Just a few “gotchas” that pop into mind:

1. Some of us use multiplier power supplies that output fairly smooth DC and some of us use unfiltered line frequency power supplies (x-ray type) that output a large amount of ripple…ripple whose amplitude changes with the amount of power drawn.

2. And we’re trying to measure that ripple with home-made divider networks we’ve constructed out of components we find wherever we can. If my meter tells me I’m running at 50 kV when in actuality I’m running at 52 kV my neutron numbers have lost their shine.

3. Measuring neutron output is, at the very best, a ± 20 % proposition. (And it’s much worse than that when all one has are a few bubbles).

4. Fusor “conditioning” has a huge affect on neutron output. For example, just after my most recent rebuild my fusor’s neutron output at 50 kV, 10 mA was 6.0E+05 n/s TIER. Today, three months and ~5 hours of run-time later its neutron output is 1.6E+06 n/s at the same 50 kV, 10 mA input. An increase of 2.7 times!

Steven, your little Excel calculator is fun to play with, but I think there are just too many input variables to expect much out of it.

Jon R
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Steven Sesselmann
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Re: Bubble Calculator

Post by Steven Sesselmann »

Jon,

I agree, if the competition is close, the inaccuracies may get the ranking out of order.

Small number of bubbles I agree does not give an exact result, we could say that all acceptable entries must have a bubble count of at least 25.

The "gotchas" are what we are looking for, and if someones contraption makes it to the top of the list, we will want to know everything about that setup and what makes it work so well, that would surely create a new thread in another forum.

Likewise learning from what doesn't work, by studying the bottom of the list.

I predict that the various setups will range over 3-4 orders of magnitude, and that careful study of the good ones will show us how to push our devices further maybe by several orders more.

By the way, the results from my run with S.T.A.R. 3 were just put on the list to make it look more like a list, I realize that 5 bubbles is not statistically enough.

I can either remove it now, or mark it with ** indicating that it is a statistically unreliable measurement.

Steven
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Jon Rosenstiel
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Re: Bubble Calculator

Post by Jon Rosenstiel »

Steven,

FYI... Data from a "normal" run. (5/24/2008)

Input voltage: 50 kV
Input current: 10 mA
TIER: 1.6E+06 n/s
Q: 3.92E-09
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Steven Sesselmann
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Re: Bubble Calculator

Post by Steven Sesselmann »

Jon,

A little bit lower than your best run, so I won't update the list unless you want me to.

Steven
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Richard Hull
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Re: Bubble Calculator

Post by Richard Hull »

This entire thread should have been posted in the files forum. As this is a file record of fusor runs. It might also have been placed to good advantage in the fusor operation forum. It will have to stay here, nonetheless. I am sure that this string of replies will expand nearly forever here. Please start no new posted threads related to this subject here in this forum. Replies to this immediate thread seem enevitable and are OK.

Ricahrd 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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