Cheap Anti-Matter?

[Mike Holmes]

Sure, there may be implcations of the destruction of the billions of positrons. Not sure how much energy that comes to, but it's not a lot of mass. My point is that getting this to work with the nuclear pulsed drive idea seems to indicate that getting that to work would take more than just pointing and shooting, but careful control of the process. I'm guessing it might be similar to the complexity of controling plasmas, perhaps. In other words, not simple. In other words, as long as you don't lose your drive, you're probably not in danger of terrorists building one.

If you're worried about losing dangerous items, start with plain old nuclear weapons. Security threats exist, sure. I just am not seeing any worse a threat here than any other of WMD becoming easy to make.

Again, unless the laser in question is buildable without a lot of technical knowledge, and those billions of positrons amount to a lot of energy. But my instinct is that, since this is not a net energy scheme, that firing the laser probably takes more energy than the positrons will create on impact. So in that case, then simply firing the laser at something is probably more harmful than the positron creation scheme.

Or am I missing something?

High energy lasers are dangerous? Well... sure...

Mike

[MSimon]

Making anti-matter gains you nothing unless you can store it.

Otherwise you might just as well use the electricity that runs the laser to boil water.

[Helius]

Sure, there may be implcations of the destruction of the billions of positrons. Not sure how much energy that comes to, but it's not a lot of mass. My point is that getting this to work with the nuclear pulsed drive idea seems to indicate that getting that to work would take more than just pointing and shooting, but careful control of the process.

The Nuclear "Catalysis" and pulsed drive thing was with Anti-Protons, not positrons. They didn't figure a way to make prodigious anti-protons, which having a negative charge and high mass, would have a fantastic affinity for normal nuclei. Positrons, having a positive charge as do normal nuclei and carry nearly no momentum, probably couldn't be used for nuclear "catalysis".

...
Again, unless the laser in question is buildable without a lot of technical knowledge, and those billions of positrons amount to a lot of energy. But my instinct is that, since this is not a net energy scheme, that firing the laser probably takes more energy than the positrons will create on impact. So in that case, then simply firing the laser at something is probably more harmful than the positron creation scheme.

Or am I missing something?

High energy lasers are dangerous? Well... sure...

Mike

The anti-protons, (again, not positrons) would cause a spall of Neutrons upon hitting a heavy target of some types, which could cause a chain reaction, not requiring a critical mass. Such a device could cause chain reactions in mustard seed sized targets, say 100 per second....

Anti-protons are a lot tougher to make than positrons; Think E=MC**2 except you're using energy to make mass, anti-protons, which are 1000 times more massive that positrons.

[Aero]

Either store it or use it as you make it.

[MSimon]

Either store it or use it as you make it.

For experiments this is useful. For storage not so much. The resulting beam is probably not collimated enough.

[Aero]

The article said that the positrons came out in a cone shape so not very collimated at all.

Actually, I would say that if I had a point, it was that the design of machines using this material will need to include the function of creating the anti-matter on the spot as it is needed and used. Sort of a "just in time" concept for the antimatter inventory.

Regarding the laser energy required, as Heilus pointed out, it will take quite a bit if it can be done at all. Hopefully that will put it out of the range of the roadside truck bomb types, but it still might be within the range of laser fusion devices. But first things first. Does the technology offer the hope of creating the right antimatter particles to catalyze fission/fusion? Well, sure, we can always hope, but realistically?

[gblaze42]

I've been scouring the internet for more info, but I would like to know what the energy levels of the positrons are when produced?!

[Mike Holmes]

Yeah, I had missed the detail about the pulse drive requiring anti-protons. So it sounds like the danger (and the benefits) in question for this synergy are at the moment non-existent? Dr. Carlson brought it up... I wonder if there's a potential to make anti-protons at all. I mean, if they are 1000 time more massive, then the energy required would be 1000 times more to creat them, yes? So if the energy in question produced billions of positrons, could it somehow produce millions of anti-protons (or something on that order of magnitude)? Would that be enough for the process above?

In any case, I think it's proabably far too early to predict anything about the capabilities here at all. But it does look worth investigating.

Any other things one can do with that many positrons? No way to leverage it for Polywell, for instance? Reverse the polarity? Send in positrons to create a positive charged well to attract in negatively charged ions? I suppose as those are more massive, that's not a good idea. To say nothing of the problem of the anihilation of the matter when the positrons collide with something inside of the reaction chamber.

Just brainstorming.

Mike

[MSimon]

Actually the number is 1800 - the mass of the electron vs the mass of the proton.

Last time I looked it was 1822.8552 aprox.

[Mike Holmes]

I think that, since the article only mentioned the order of magnitude (billions), that he was mentioning just the order of magnitude. Accurately, by your estimations. Anyhow that's how I did my calculation, and just to get an idea if it was remotely possible at all to get a requisite number of anti-protons. Millions (or even half a million) sounds substantial. But I may be wrong in many ways:

1. Perhaps it doesn't scale linearly. If the energy required is at the square od mass, for instance, then we're down to only thousands or hundreds of anti-protons.
2. Can the technology produce anti-protons at all?
3. Maybe that many protons is some orders of magnitude less than needed to cause the chain-reaction in question.
4. The collimation question that was brought up... if they scatter, is it useful for this purpose, even if we can make enough? Can they be collimated after emission somehow (seems unlikely, due to the potential for anhillation, but perhaps magnetically)?

In any case, my original point remains, too, that even if we had the anti-protons, the article on wikipedia (for whatever that's worth) states that it's not as simple as firing them at fissables to get a chain reaction. There are "technical issues" on timing and such that might make it only feasible for those with a lot of technical knowhow to produce this as a weapon.

So I'm not too worried about it as a weapon. Right now I'm just pulling for it to mean a better propulsion system.

Mike

[Aero]

Big Oops - The picture in the first article linked in this thread shows the investigator at the Jupiter Laser Facility setting up targets.
https://lasers.llnl.gov/programs/scienc ... es/jlf.php
That laser ain't gonna fit on a truck!

[Mike Holmes]

Yeah, and one of only three in the world in the petawatt range. That's a lot of mass to have to carry on a spacecraft, too, unfortunately...

How about for positron microscopy?

Mike

[kurt9]

Big Oops - The picture in the first article linked in this thread shows the investigator at the Jupiter Laser Facility setting up targets.
https://lasers.llnl.gov/programs/scienc ... es/jlf.php
That laser ain't gonna fit on a truck!

This is what I thought, which means that this is not really a practical method of manufacturing of anti-matter.

[Skipjack]

Yeah and unless you have a nuclear powerplant (to provide the entergy for that laser) that fits on a truck, even making the laser itself smaller, wont help either...

[djolds1]

Am I getting this right. Put some nuclear material next to this antimatter source and BIG BOOM! That easy?

That is a profoundly scary thought.

There are quite a few more ways to create BIG BOOMS than just Teller-Ulam fission-fusion-fission bombs. Easy ways that few people talk about.

I can think of three off the top of my head.

Duane