Bubble Calculator

A place to keep track of reference material - any particularly useful books, articles, etc. should be listed here.
User avatar
Steven Sesselmann
Posts: 2111
Joined: Thu Aug 11, 2005 1:50 am
Real name: Steven Sesselmann
Location: Sydney - Australia
Contact:

Bubble Calculator

Post by Steven Sesselmann » Fri May 23, 2008 12:58 am

This thread has been moved to:-

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

...a more appropriate forum.

Steven
http://www.gammaspectacular.com - Gamma Spectrometry Systems
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG

Jon Rosenstiel
Posts: 1368
Joined: Thu Jun 28, 2001 5:30 am
Real name: Jon Rosenstiel
Location: Southern California

Re: Bubble Calculator

Post by Jon Rosenstiel » Fri May 23, 2008 2:02 am

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

User avatar
Steven Sesselmann
Posts: 2111
Joined: Thu Aug 11, 2005 1:50 am
Real name: Steven Sesselmann
Location: Sydney - Australia
Contact:

Re: Bubble Calculator

Post by Steven Sesselmann » Fri May 23, 2008 4:14 am

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
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG

Wilfried Heil
Posts: 590
Joined: Sun Dec 25, 2005 12:31 am
Real name:

Re: Bubble Calculator

Post by Wilfried Heil » Fri May 23, 2008 2:57 pm

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.

User avatar
Steven Sesselmann
Posts: 2111
Joined: Thu Aug 11, 2005 1:50 am
Real name: Steven Sesselmann
Location: Sydney - Australia
Contact:

Re: Bubble Calculator

Post by Steven Sesselmann » Fri May 23, 2008 3:17 pm

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
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG

Jon Rosenstiel
Posts: 1368
Joined: Thu Jun 28, 2001 5:30 am
Real name: Jon Rosenstiel
Location: Southern California

Re: Bubble Calculator

Post by Jon Rosenstiel » Fri May 23, 2008 8:02 pm

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

User avatar
Steven Sesselmann
Posts: 2111
Joined: Thu Aug 11, 2005 1:50 am
Real name: Steven Sesselmann
Location: Sydney - Australia
Contact:

Re: Bubble Calculator

Post by Steven Sesselmann » Fri May 23, 2008 11:10 pm

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
http://www.gammaspectacular.com - Gamma Spectrometry Systems
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG

Wilfried Heil
Posts: 590
Joined: Sun Dec 25, 2005 12:31 am
Real name:

Re: Bubble Calculator

Post by Wilfried Heil » Sat May 24, 2008 11:19 am

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).

User avatar
Chris Bradley
Posts: 2931
Joined: Fri May 02, 2008 11:05 am
Real name:

Re: Bubble Calculator

Post by Chris Bradley » Sat May 24, 2008 3:38 pm

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.

Q
Posts: 200
Joined: Mon Jan 12, 2004 10:45 pm
Real name:

Re: Bubble Calculator

Post by Q » Sat May 24, 2008 3:49 pm

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

Q

Post Reply