Pulsed Fusor #4 Buiding a 300 watt fusor 3/15/02

[guest]

under construction:
Will be updated as new stuff happens.

Read this first>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Warning this is an attempt at a medium power fusor.
Standard shielding will not work at these levels. ( steel vessel)
I would hate to lose friends to lethal doses of x-rays
and neutrons.
Pulse systems are not toys.
A dug out or pit will be needed during even early tests.
If you come up with the right combination rad levels would cause radiation poisoning if conducted in your garage.
You can still use your garage as a instrument shack,
but a cinder block box filled with iron filings and boraxo laundry soap $2.99 / 4lb box
would work... out in the yard. Under would be best.

The whole fusor will have to be housed in a faraday cage. This includes power supply also. About the last
thing this group needs is to have a member destroy
a power grid by emi overload. Law suits galore! Not to mention the possible damages to properties and loss of life. This means battery powered fusor supplies also. A fusion test shot will kill tv reception, burn up comos ic's, kill anything with intelligence in it, cars ,microwave ovens, wireless phones, pace makers and biomedical implants. It needs proper shielding.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

I'm now ready to actually build the wee beasty.
My first attempt will not be the one horse fusor .. as yet.
A more modest number comes to mind like 300 watts.
Less than 1/2 the power of the one horse fusor but competative with other alternate energy like a 200 watt solar panel. Oh yeah the conversion factor for steam generation is only forty percent at best so for the fusor to be competative with a 200 watt electrical solar panel it must generate about 300 thermal. I figured that if this technology is to be taken seriously it must compete in the alternate energy arena. If I can get this to work then other methods like liquid metal MHD can be used to raise the carnot efficiency. I have no clue how long this effort will take.

But here goes.

Input Joules........Cat D-D Reaction.......Output Mev

3.8E-14..............D + D = He + N.................3.3
3.8E-14..............D + D = T + P....................4.0
7.2E-14..............D + T = He + N................17.6
_________________________________________
14.8E-14.........................................................24.9
Mev to Joules (2.49E7ev)(1.60E-19 joule/ev)=
3.98E-12 joules
To find the energy released re = output energy - input energy

39.8E-13 joules-1.48E-13 joules = 38.32E-13 Joules

re=38.32E-13 joules per each catalysed fusion

Next multiply 300 watts by 1 second to get 300 joules.

Then divide 300 joules by the 38.32E-13 joules to see how many fusion reactions that is.

When I do that I get 7.83E13 reactions.

Even at 300 watt the level of production it's n=i^3 (third power scaling)

so we plug in the # of neutrons to get the # of amps we need.

7.83E13 =i^3

i = 3.84E4 Amps X2= 6.96E4 Amps (thought I forgot about the two reactions..huh?)

watts = 6.96E4 x Operation voltage

@ 10 kev watts=6.96E4 x 1.00E4 = 6.96 E 8 watts

@ 15 KEV watts= 6.96E4 x 1.5E4 =1.04 E 9 watts

I have a laser capacitor that will discharge in 50 ns .
(low inductance)

so at 50 ns
@10 kev
Joules required= 6.96 E 8 watts / 5E-8 sec = 1.47 joules

@15 kev
Joules required= 1.04 E 9 watts / 5E-8 sec = 2.08 joules

My capacitor is rated at 2microfarad 15 kev

so joules =.5cv^2=.5(2 e-6 farad)(1 E4 volts)^2= 100 j

But a capacitor can only deliver 60% of the total value without causeing damage to the diaelectric in repetative shots.

So 100j x .6 =60J more than adequate for a demo at both test voltages.

My first model will be detailed in Test Article "A"

My second model will be a one shot device fully monitored
with a triggered spark gap designed to discharge in 50 ns.
A micro marx generator will provide the 50 ns triggering pulse. It is run by an automobile ignition coil and capacitor ( I will detail in a seperate post.)

The third step will incorporate all the data gained in the previous steps in order to build the 300 watt pulsed fusor that will be the power plant. (maybe).

My second device is to be housed in a ss bell jar. (Glass won't cut it)
The outer grid is four inches in diameter.... made of welding wire.
The inner grid will be a 1.2 inch diameter made of
spot welded tantallum wire or tungsten wire.
After concideration I redesigned the grid system to use a heat sink cooled by water.
This design will incorporate a half sphere on the positive ground side with a woven grid on top so you can see. The inner grid will be cooled by the feedthru.
( what a chicken!)
It will be tested at a partial scale to check it out.
( Run in test Article "A" in minature.)
The pump is the standard pump with diffusion pump working at 10 torr with backfilled deuterium gas through a calibrated leak.
The third unit will be a ss cylinder in a ss cylinder it will be surrounded by a Li6 depleted lithium blanket.

My borrowed vacuum pump has to go back.
I borrowed it from my friend in the neon business.
It was a backup.
His main pump threw a bearing and has to be reworked.
Hence no pump for now.
I'm still waiting on the diffusion pump.
Diffusion pumps have some hetertofore unknown gold in them.
On Ebay they are fetching pretty high premiums lately.
I wonder how hard it would be to build?
While I'm at it build two.
Varian Vacuum Gauge controller is functioning .
IT's a Varian 927-0003 ....
The Baird Alpert Gage is next (I Have other stuff that needs this high level gauge 10^-10 Torr)
Building Thermo couple gage controller ala Belljar.

My low power supply is done.
My goal is 100 kv at 2 amp.... want to check out double well pulse regeam.

I'm designing a 100kv cap for a pulse cap. (yike)
If all goes well I'll be running on a x-ray power supply.
100kv at 60ma rating fed to a capacitor.
The only draw back is you need a fairly hefty variac to run it. My power pack is wired dirrectly to the breaker box. A 100 amp breaker is used.
Now upgrading my power lines to 000 wire.
The gizmo draws 6 kw!
I've crossed the line into the civilian industrial complex.

Vacuum fead thru is here.
Spot welder is ready.
Thinking about tantulum wire.
Test stand is still to be built.
Test site is cleared and ready to receive concrete.
Bunker Layout is complete.
Started to build the 50 ns Minimarx Generator.
About 1/2 done with test article "A"
Working on spark gap.
My shot shack is being renovated to a dry building.

The deuterium gas is put off untill I pay off my Toshiba x-ray rig..
My detectors are here but much testing and calibration to do.
Just starting on my nim rack.
Just got my first sca module.
Just got my first Amp.


If this stuff is attractive to you then join the Bell Jar.

Just got a couple of thyratrons RCA 3C45.... Low power but ok in this application.... it's a start.
Working on a better way.

Septic hole dug needing small tank.
Bathroom shell complete.
Plumbing and flooring next.
Small table with electric outlet for dorm refrigerator and the umbigous microwave oven (curb side pickup and repair).
MAN.....This stuff will sure keep you off the streets. (Broke!)

And most importantly as Homer Simpson would say
A refrigerator and full rest facilities with a couch for late work. Coffie Power!



I really appreciate Scott Little's Earth Tech site picture gallery. It was inspirational.
I miss UT at Austin.

Larry Leins
Physics Teacher

[guest]

I havn't gone through the calculations in detail. However, it looks like you are saying 60 (100) joules in and 300 joules out. Are you suggesting that you are going to be able to produce excess energy? I am probably missing something in the details.

Also, how does fusor technology compare with the lawson criterium?

Thanks,

Bob
3L wrote:
> under construction:
>
> Read this first>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> Warning this is an attempt at a medium power fusor.
> Standard shielding will not work at these levels. ( steel vessel)
> I would hate to lose friends to lethal doses of x-rays
> and neutrons.
> Pulse systems are not toys.
> A dug out or pit will be needed during even early tests.
> If you come up with the right combination rad levels would cause radiation poisoning if conducted in your garage.
> You can still use your garage as a instrument shack,
> but a cinder block box filled with iron filings and boraxo laundry soap $2.99 / 4lb box
> would work... out in the yard. Under would be best.
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>
> I'm now ready to actually build the wee beasty.
> My first attempt will not be the one horse fusor .. as yet.
> A more modest number comes to mind like 300 watts.
> Less than 1/2 the power of the one horse fusor but competative with other alternate energy like a 200 watt solar panel. Oh yeah the conversion factor for steam generation is only forty percent at best so for the fusor to be competative with a 200 watt electrical solar panel it must generate about 300 thermal. I figured that if this technology is to be taken seriously it must compete in the alternate energy arena. If I can get this to work then other methods like liquid metal MHD can be used to raise the carnot efficiency. I have no clue how long this effort will take.
>
> But here goes.
>
> Input Joules........Cat D-D Reaction.......Output Mev
>
> 3.8E-14..............D + D = He + N.................3.3
> 3.8E-14..............D + D = T + P....................4.0
> 7.2E-14..............D + T = He + N................17.6
> _________________________________________
> 14.8E-14.........................................................24.9
> Mev to Joules (2.49E7ev)(1.60E-19 joule/ev)=
> 3.98E-12 joules
> To find the energy released re = output energy - input energy
>
> 39.8E-13 joules-1.48E-13 joules = 38.32E-13 Joules
>
> re=38.32E-13 joules per each catalysed fusion
>
> Next multiply 300 watts by 1 second to get 300 joules.
>
> Then divide 300 joules by the 38.32E-13 joules to see how many fusion reactions that is.
>
> When I do that I get 7.83E13 reactions.
>
> Even at 300 watt the level of production it's n=i^3 (third power scaling)
>
> so we plug in the # of neutrons to get the # of amps we need.
>
> 7.83E13 =i^3
>
> i = 3.84E4 Amps X2= 6.96E4 Amps (thought I forgot about the two reactions..huh?)
>
> watts = 6.96E4 x Operation voltage
>
> @ 10 kev watts=6.96E4 x 1.00E4 = 6.96 E 8 watts
>
> @ 15 KEV watts= 6.96E4 x 1.5E4 =1.04 E 9 watts
>
> I have a laser capacitor that will discharge in 50 ns .
> (low inductance)
>
> so at 50 ns
> @10 kev
> Joules required= 6.96 E 8 watts / 5E-8 sec = 1.47 joules
>
> @15 kev
> Joules required= 1.04 E 9 watts / 5E-8 sec = 2.08 joules
>
> My capacitor is rated at 2microfarad 15 kev
>
> so joules =.5cv^2=.5(2 e-6 farad)(1 E4 volts)^2= 100 j
>
> But a capacitor can only deliver 60% of the total value
>
> So 100j x .6 =60J more than adequate for a demo at both test voltages.
> My first model will be a one shot device fully monitored
> with a triggered spark gap designed to discharge in 50 ns.
> I have a variac and a unregulated supply to provide the voltages to the capacitor using inductance charging method to reduce losses that a charging resistor would cause.
> My device is housed in a bell jar.
> The outer grid is eight inches in diameter.... made of welding wire.
> The inner grid will be a three inch diameter made of
> tantallum wire.
> The pump is the standard pump with diffusion pump working at 10 torr with backfilled deuterium gas.
>
> Im still waiting on the diffusion pump.
> My power supply is done.
> Test stand is still to be built.
> The deuterium gas is next in the pay cycle.
> My detectors are here but much testing and calibration to do.
> If all goes to plan My first shot tests will begin at the end of March.
>
>
>
>
>
>
>
>
> Larry Leins
> Physics Teacher

[guest]

In short the answer is yes under i^3 scaling.

The Lawson citeria is a slippery issue .
Most formulas for it are specifically for magnetic not electrical fusion. To see the problem look at "The Fusion Quest " by T. Kenneth Fowler. ISBN # 0-8018-5456-3

p14 I quote "We charaterize the effectiveness of the magnetic insulation in terms of the "energy confinement time," Which is the time required for the plasma to cool off if all heating ceased." Most of the time factors assume that the deuteron will precess in a tokamak raceway for a total of 600 miles of travel round and round. The loss is supposted to be offset by neutral deuteron injection or microwave heating to the tune of 100 Megawatts. All machines of this nature
have never reached unity. The fusor on the other hand has a travel length measured in inches. In the tokamack machines heating is suppost to be pure I^2
but their insanely long reaction times require miles of travel. In the fusor reaction occurs in less than a millisecond after it crosses the inner grid.

In a pulsed fusor the reaction time is measured in nanoseconds which gives little time for radiative loss mechanisms to set in. This is all new ground, the time constant factor will have to be measured by experiment.

Larry Leins
Physic Teacher

[guest]

Larry,

How have you configured for glow prior to pulse- will this be low current DC or perhaps RF?

Demo system (air only) with RF excitation is very pretty as well as adjustable.

Your capacitors are homemade or commercial?

Cheers,
R

[Richard Hull]

A pulsed fusor is a real project. I think Larry is in the designing stage and #4 is a design alteration before construction. At least that is my take on things.

I have many ideas on pusled fusion, but having measured in noisey environments before, neutron counting in the submicrosecond time frame (even the single digit microsecond time frame) is just not doable in any form by a casual amateur. A pulsed fusor will put out an EMP of over a megawatt at whatever the circuits ringup natural period is. (megahertz or less). In addition, the chamber itself is a resonant cavity in the gigahertz range. The average energy signal from a PMT is over 12 orders of magnitude less and a BF3 tube even less than that.

Now what is signal out of your detector and what is emp? How many of you think you can effectively shield normal instrumentation against pickup?

With sub-megahertz ringinging joining gigahertz ringing... with perhaps other sympathetic circuit ringups/ringdowns going on for tens of microseconds and the neutron pulses coming in a time window just slightly off coincidence with the pulse to the fusor....Where's th' beef!

Neutron metrology would be the success story here.... not the fusor!

Good luck to all in this effort. It has kept me out of this arena for two years as I mull over the daunting instrumentality issues.

I'll move this to the radiation forum for my thoughts.

Richard Hull

[guest]

The glow is provided through low current discharge.
(Resisistor bridge)
My capacitors are store bought for now ... just to get my feet wet. 2uf @ 15kev ... Ebay purchase

EMP and measurement problems kept me out of the game for two years while I thought about it.

I think it could be solved by Faraday shielding with a
PMT operated via fiber optics. Another reason yet to isolate my instruments from the test chamber.
I borrowed the idea from the nuclear test program.
I used the non classified solution availible in many textsbooks on emi and emp.
They have batteries of high potential to run Pmt using
audio transformers turned backwards. You could use a 6 volt power transformer instead. A motorcycle battery could run lots of stuff in a compact area. An iron case (soft) surrounds the PMT electronics to protect from induced emp currents. A LED transmitter is wired to into the output from the PMT preamp. Some logic could be employed to convert it to digital but analog works just fine ( I hate unnessary work ... got plenty thank you)
A photo transistor of fast rise time could output to the nim crate amplifier. The schintillator must be covered with a shim of aluminum. Thin enough to shield EMP but thick enough not to burn during discharge.
Or block the neutrons.
BF3 counters in shot holes since the late forties used this technique. They don't produce them in glass for this very reason.
Run two fiber lines if you want a cheap solution for many detectors in box. Or be a tech weiner like me and design a time division multiplexer in order to run up to 16 instruments. ICs are fairly cheap .... rework time is hard to come by. Design ahead. I plan to make This unit retrievable on a bean pole for updates. The fiber line is bent into a zigzag pattern to kill emf induction through a hole in the box . On the backside of the hole is a conductive box lined with ferrite rings or a laborynth lined with conductive plastic. Which the fiber runs through.

The Emp has been attenuated sucessfuly in nuke weapons tests by parasitic cavities lined with conductive foam.
Sub micro second counting could be acheived by putting a tunnel diode divider on the front end. ( not cheap I know but cheaper that mecl3 dividers.)



Larry Leins
Physics Teacher

[jim-frank]

Maybe an approach to measuring the neutron flux would be to measure the activation decay energies. A whopping pulse of fast neutrons could be moderated to produce a fairly good number of thermal neutrons to activate something with an easily detected gamma spectrum, couldn't it?
Jim Frank

[guest]

This is probably a crude solution to the problem but here goes... It sounds like Larry knows what he is talking about. But for those who don't know what he does, how about just putting some kind of element with a known capture cross section in near proximity to the chamber. Ideally it should be a material with a relatively short half life (seconds or minutes). By firing several shots and then measuring the induced radation by simpler means one could the measure the rate of decay and reverse engineer the initial radioactivity from known half life data (radioactive decay is first order). This would then give the initial induced radation, which can then implicitly give the neutron flux based on the capture cross section, distance thickness etc. Maybe this isn't simpler but it seems so to me.

[Richard Hull]

Again, This discussion should and must be part of the Radiation metrology forum!!!

I have posted on this yesterday in that forum to start a proper thread.

A couple of shots would do nothing detectable by amateur efforts.

Threads on construction that drift off construction should resume in the proper forum. Otherwise newbies will be asking questions we have already covered regarding activation but have no learning path becasue they were STUPIDLY looking for issues and solutions regarding neutron or radiation metrology in the radiation/neutron metrology forum while we so WISELY posted their solution eight posts deep in the "construction forum" under the radiation metrology specific title of "Pulsed fusor #4".

If that sounds stupid, lets please post real solutions and discussions on specific issues in forums where the smart mind would search for them. I know the mind wanders over many threads, but how many golden tid bits are permenantly hidden from, and lost to, inquiring minds due to casual topic drift in off-topic replies.

We are mostly all guilty of it.

Check the recent posts on neutron activation in the radiation section.

Richard Hull

[guest]

I read you 10 by 10.
I've reposted under neutron detection.
But I can not garantee they are the same.
I know what you mean by all spread out.
Will comply.

Larry Leins
Physics Teacher

[Richard Hull]

No finger pointing here.

Actually, If you examine the thread I pulled it off topic by talking about neutron measurement issues, but gave no specifics. Then specifics were suggested by jim and others..........a natural course of events.

My next reply suggested moving to the metrology forum as I realized the Jim's, Larry's, Bob's and my own comments were perhaps gems of activation analysis discussion that might never be appreciated to a later audience, buried as it was in an off topic issue.

We just need to keep our wits about ourselves in future in reply. Someone needs to belly up to the bar and derail the discussion in their reply to the proper forum with no malice being understood, just proper posting for those curious, latter day newcomers.

In this manner, newcomers looking at construction will see there are neutron measurment issues associated with pulsed fusor operation and follow the suggested path over to the metrology forum around about the same posting date.

Likewise, when the discussion moves, it is incumbent on the derailer to give a clean and clear title to the first posting in the new forum as to what the new "stand alone" posting relates to. In this case, "pulsed fusor neutron activation". This also allows someone not even following the construction derailment who is just looking for activation discussions in the radiation measurement forum to have a vivid handle for a totally separate successful search on the activation issue in general.

This may sound tedious, but it keeps all our gems of knowledge in the proper file drawer.

Richard Hull

[guest]

I know no fingers were pointed.

This group is becoming a large organization.
Thirty members and counting.
I tried to advise the only female to wander into the site,
but it was daunting. I know where everything is but just remember I had two years to look. I have read and digested most of the literature and read 200-300 books just to be realevent. If young people are to get with us old retired hacks in the fusion game some sort
of educational section must be opened. I was the dependent husband of a college professor, I had unlimited access at the junior college level. I had great instructors. My range of scope is a bit unusual. I have over 300 hours of college, not counting Ole Miss.
I simply took everything. It was free. Took about twenty years but I almost had a complete set courses. All the chemistry. All the engineering physics. All the mechanical engineering and metallurgy with welding and machine shop. All the computer repair. All the industrial controls and robotics. All the mathematics. Most of the computer science. And a whole catalog of electives. I even conducted superconducting reseach at the JC Level. Learned material science on the side.
It was a natural thing for me to crawl through the web site but Kids without my background could be bumfuzzled by the bewildering complexity of the site as it's becoming.

Maybe now before we get much bigger, a newcommer
welome forum with a tutorial is in order.
The time spent on it would free up time for doing the work, rather that answering the same questions over and over again.
This has been posted in general topics also.

Larry Leins
Physics Teacher