Converting drive voltage into collision energy.

It may be difficult to separate "theory" from "application," but let''s see if this helps facilitate the discussion.
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Re: Converting drive voltage into collision energy.

Post by MSimon » Mon May 12, 2008 6:11 pm

I remember the early days of amateur computing. A lot of things were going on in parallel.

I was still struggling with I/O and memory while others were adding disk drives to their systems. Later folks just bought built systems and started doing software experiments. I do have the honor of designing and manufacturing the I/O board that went into the world's first BBS. I didn't even have a modem at the time.

Other folks (Ted Nelson for example) were on the side lines dreaming of what could be and encouraging the more technically minded to have at it.

Of course you have been waiting a long time to see p-B11 fusion. There are not enough people working on the problem. The early days of amateur computing were like that. With no standard systems and everything custom roll your own advances were slow. Things didn't start popping until Jan '75 when Popular Electronics came out with the Altair on their front cover. (That is when I joined up). Then we got inflation of the ranks. The second major jump came in the early 80s with the IBM PC.

Right now we are in the pre-'75 era. That will change when some one comes out with a $5,000 fusion kit. (BTW I gave away a $5,000 S-100 dual 8" disk drive computer to a friend when I moved on to IBM PCs so a move to commercial products will advance the abilities of even the most broke hobbiests - in time).

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Chris Bradley
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Re: Converting drive voltage into collision energy.

Post by Chris Bradley » Mon May 12, 2008 8:29 pm

Just to clarify - I'm happy to do the pure theoretical calculation, but that doesn't mean I'd suggest it is viable (I think I added that caveat!).

I presume that any real serious look at p11B should come to the conclusion that the effort of getting 11B into motion seems considerably outweighed when compared with the relatively simple task of accelerating a proton, notwithstanding the x 3 voltage required. It's the relative velocity, not lab energy, so no real benefits to accelerating the heavier particle. I never quite understood that part of Bussard's argument, that 11B would only need 1/5th of the voltage drive.

In fact, given the calcs above, if at all possible you would have to put in 345keV of lab energy to get a 'head-to-head' p11B/148keV collision going, whereas just accelerating a proton into a 11B lab-target takes just 162keV of energy. You'd instantly double your efficiency by a beam-target approach!

best regards,

Chris MB.

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Re: Converting drive voltage into collision energy.

Post by Dustinit » Tue May 13, 2008 6:51 am

I noticed that the velocities are exceeding that of 1% of the speed of light,
and was curious whether that reduces the velocities (ev) required as the apparent mass increases and cross sectional area would begin to increase due to relativistic effects.

mmm
Dustin

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Chris Bradley
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Re: Converting drive voltage into collision energy.

Post by Chris Bradley » Tue May 13, 2008 8:46 am

Numerically, the variation of mass is ~2 parts in 10,000. Experimentally, I would suggest that's unmeasurable at this velocity for this type of experiment.

I'm not sure the question makes sense with regards cross-section. Again, cs is an experimental measure that I understand to have much bigger uncertainties than this, but when measured it's referenced to the CofM collision energy anyway which, I presume, must work out to be frame invariate for any observer else you'd never know what reference frame to actually use for the calculation!

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Re: Converting drive voltage into collision energy.

Post by giorgos giorgakis » Mon Nov 09, 2015 5:07 pm

Hi sorry for the necro post but what is the required energy for p-B11 fusion after all? I see that you use Boron 5+ for your calculations( which is hard to make ) and with what frame of reference? The papers you mentioned say 150keV plasma energy not ion energy which is different and you also have to take relativistic effects into account in such speeds. For 56.7 keV I get 3.32x10^6 m/s for the proton and 3.10x10^6m/s for the B5+ since you have to take the charge also into account, with the lab as a reference frame, so the relative speed for the two ions would be ~6.4x10^6 m/s given the reference frame of the lab, much higher than the combined 150keV you said in the first place. The speed for B+ is 1.07602*10^6 though which is more realistic. If 150keV absolute energy is needed then the speeds are different. When you take relative speeds with reference to the B5+ w/ lorentz transformations you get 4.31984*10^6 for the proton.
Last edited by giorgos giorgakis on Mon Nov 09, 2015 11:40 pm, edited 3 times in total.

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Re: Converting drive voltage into collision energy.

Post by John Futter » Mon Nov 09, 2015 5:25 pm

giorgo
how about following the forum rules and introducing yourself first before posting elsewhere
and please change your logon to your full real name

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Re: Converting drive voltage into collision energy.

Post by giorgos giorgakis » Mon Nov 09, 2015 6:13 pm

Ok then although there arent many things to say about me. The real question would be 150 keV on what reference frame?

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Paul_Schatzkin
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Fuel Cycles, Energy Levels

Post by Paul_Schatzkin » Mon Nov 09, 2015 7:02 pm

what is the required energy for p-B11 fusion after all?
Giorgos,

Welcome and thanks for using your real, full name (and thanks John F for monitoring the case. Still amazes me how hard it is for people to follow simple instructions... <*sigh*>.

I have been reading up on fuel cycles a bit myself lately, maybe this has the answer to your question?

http://www.visionofearth.org/industry/f ... they-work/

This might be the money quote:
There is only one major disadvantage to this fuel cycle, but it is a big one. The reaction rate peaks at an energy of 123 keV! This is a very high energy, so high in fact that many people consider this fuel cycle to be a dead end in terms of research.
Does that answer your question?

--PS
Paul Schatzkin, aka "The Perfesser" – Founder and Host of Fusor.net
Author of The Boy Who Invented Television - http://farnovision.com/book.html
"Fusion is not 20 years in the future; it is 50 years in the past and we missed it."

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Richard Hull
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Re: Converting drive voltage into collision energy.

Post by Richard Hull » Mon Nov 09, 2015 9:05 pm

Giorgos,

There is no "required energy" for p-B11 fusion. The fusion reaction picks up as the applied potential, (relative ion velocity increases). There is always a maximum or optimum production energy which if exceeded will actually result in less fusion due to an oppenhiemer-philips type reaction which is not fusion.

As most fusion attempts are thermal ones P-B11 is sort of a dead end as there are other reactions in the thermal range which would be far easier and yet, even they have never been successful in producing net energy.

In a collisional accelerator regime the P-B11 reaction is much easier to achieve, but the same ultimate limitation appears so far as net energy production is concerned. Far more input energy is required and wasted in the effort than fusion energy created by the effort.

In general, in a fusor type, collisional accelerator regime, you would need a collisional energy for the fuel element ions on the order of 125kev to be near an early optimum peak. Note: the real maximum peak is way out at 700kev

It is easy to talk of getting ions to that target energy, but another to actually herd them to that level to do advantageous fusion.

I am rather stunned you did not do a simple google search on the cross sectional data...... I did and all this has been covered in great detail here in prior postings

http://www.crossfirefusion.com/nuclear- ... actor.html



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
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Re: Converting drive voltage into collision energy.

Post by giorgos giorgakis » Mon Nov 09, 2015 11:32 pm

Hi thanks for the replies and links , all sources I've found treat the ions as gases and they should for a large amount of ions but I want to calculate the energy needed for a head on collision of 2 ions p-B+ without taking into account the collision cross section and other gas theories.

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