LLNL Claims Cheap Anti-Matter Breakthrough

[sanman]

Making the round of tech sites everywhere, is news of some LLNL breakthrough that could enable the efficient/cheap production of anti-matter:

https://publicaffairs.llnl.gov/news/news_releases/2008/NR-08-11-03.html

Well, seeing as how you can't get a higher-energy-density fuel than matter-antimatter, could this mean we could have rocketships running on the stuff?

 

[Vanadium 50]

No. First, you need energy to make antimatter, and the amount you put in compared to what you get out makes the cost prohibitive. Second, these are positrons, which don't have much mass, and you can't put too many of them in one place before the electric field becomes so large you can no longer store them.

 

[sanman]

Well, they're claiming some unprecedentedly high efficiency.

Furthermore, what if they find a way to do it for anti-protons?

What if significant quantities of anti-hydrogen could be produced?

Furthermore, how much mass would really need to be produced, to become useful for spacecraft ? Not that much, I'd imagine.

 

[sanman]

http://en.wikipedia.org/wiki/Antimatter_catalyzed_nuclear_pulse_propulsion

http://en.wikipedia.org/wiki/ICAN-II

http://en.wikipedia.org/wiki/AIMStar

http://en.wikipedia.org/wiki/Antimatter_rocket

 

[Vanadium 50]

Well, they're claiming some unprecedentedly high efficiency.

Yes, but it's still low in absolute terms. 100 billion positrons have an energy of 0.008J. If the plasma were obtained by plugging the machine into the wall - say 120 V at 10A for only one second (and I can assure you, it took far more energy than this), the efficiency is 0.0007%.

Furthermore, what if they find a way to do it for anti-protons?

Why would this work for anti-protons? The production mechanisms are completely different. The LLNL group isn't even trying to do this for antiprotons.

What if significant quantities of anti-hydrogen could be produced?

What if I could flap my arms and fly to the moon? You can keep saying "what if", but unless this is grounded in data, you are talking about science fiction, not science. Even a 100 billion positrons is not a substantial amount: a billionth of a microgram.

 

[sanman]

Well, still, it's a positive step, and a tantalizing glimpse at what might be possible in the future.

A short-pulse laser like a femtosecond-pulse laser could make those 100 billion positrons pretty quickly. Your rate of synthesis would probably be limited by how quickly you could put gold targets in front of the laser. If you could automate the process to speed it up and have it going around the clock, then maybe you could produce more than miniscule amounts over an appreciable period of time.

It's not clear to me what the energy efficiency of their process was. Can anyone infer it?

How much anti-matter would one need, in order to send a space probe to Alpha Centauri nearby?

 

[Vanadium 50]

A short-pulse laser like a femtosecond-pulse laser could make those 100 billion positrons pretty quickly.

Evidence?

Your rate of synthesis would probably be limited by how quickly you could put gold targets in front of the laser.

Evidence?

If you could automate the process to speed it up and have it going around the clock, then maybe you could produce more than miniscule amounts over an appreciable period of time.

Evidence?