New Laser Technique Produces Bevy of Antimatter, page 1
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reply posted on 3-12-2008 @ 08:26 AM by mdiinican
Originally posted by dashen
Hooray!, we're one step closer to anti-matter bombs! There goes the galaxy. Oh, well, I'm sure this will be used for peaceful applications first. Not.

[edit on 2-12-2008 by dashen]


yeah, just as soon as the energy to create a kiloton's worth of antimatter become cheaper than the fissile material it takes to build an equivalent sized nuclear bomb, and as soon as having weapons that are at risk of exploding in storage if they're jarred too hard, and which will explode if not kept constantly supplied with electricity isn't a problem anymore.

Any process which creates antimatter is at best 50% efficient, since it has an equal chance of creating normal matter. The antimatter reaction itself is also very inefficient, in terms of boom per energy, but typical fission bombs are too, due to unfissioned fissile material being blown away by the explosion before it can react, so I'll be generous and say that antimatter bombs only lose an equivalent amount of efficiency. So if you're using a nuclear power plant, for the same fissile material that's used up making the antimatter bomb, you could make a nuclear bomb twice as powerful, and it probably wouldn't be much heavier, due to the metastable magnetic containment bottle required for an antimatter bomb, as well as it's batteries, etc.

To conclude;
as a weapon, antimatter is only really good for making a bomb that's physically a bit smaller, and monetarily more than twice as expensive and thousands of times less safe than an equivalently powered nuclear bomb.

It really does have more utility in (relatively) peaceful roles, especially as an energy storage medium for rockets, where every gram counts.


reply posted on 3-12-2008 @ 09:50 AM by rickyrrr
reply to post by enduser


Unless otherwise specified, I assume that the net energy that can be extracted from the newly created antimatter would equal the energy delivered by the laser. Right?

-rrr


reply posted on 3-12-2008 @ 10:43 AM by enduser
Originally posted by rickyrrr
reply to post by enduser

Unless otherwise specified, I assume that the net energy that can be extracted from the newly created antimatter would equal the energy delivered by the laser. Right?


Im not entirely sure to be honest, i dont think the article mentioned the cost of running the lasers? it's certainly not cheap at $6.25 x 10¹º per milligram (according to NASA). I think at one point NASA were seeing if would be feasible to acquire the stuff from the Van Allen belt, to save on the production costs.

Heres some info about using antimatter as a fuel

The energy per unit mass (9×1016 J/kg) is about 10 orders of magnitude greater than chemical energy, about 4 orders of magnitude greater than nuclear energy that can be liberated using nuclear fission, and about 2 orders of magnitude greater than the best possible form of fusion.

The reaction of 1 kg of antimatter with 1 kg of matter would produce 1.8×1017 J (180 petajoules) of energy (by the mass-energy equivalence formula E = mc²), or the rough equivalent of 47 megatons of TNT. For comparison, Tsar Bomba, the largest nuclear weapon ever detonated, reacted an estimated yield of 50 Megatons, which required the use of hundreds of kilograms of fissile material (Uranium/Plutonium).Source


and something from NASA in 1999
The popular belief is that an antimatter particle coming in contact with its matter counterpart yields energy. That's true for electrons and positrons (anti-electrons). They'll produce gamma rays at 511,000 electron volts.

But heavier particles like protons and anti-protons are somewhat messier, making gamma rays and leaving a spray of secondary particles that eventually decay into neutrinos and low-energy gamma rays.

And that is partly what Schmidt and others want in an antimatter engine. The gamma rays from a perfect reaction would escape immediately, unless the ship had thick shielding, and serve no purpose. But the charged debris from a proton/anti-proton annihilation can push a ship. Source



reply posted on 4-12-2008 @ 11:22 PM by mdiinican
Originally posted by rickyrrr
reply to post by enduser


Unless otherwise specified, I assume that the net energy that can be extracted from the newly created antimatter would equal the energy delivered by the laser. Right?

-rrr


Actually, at best half the energy delivered by the laser. An equal amount of energy also goes into creating regular matter. Realistically it's probably less than 1% of the energy delivered by the laser, but it's still apparently a much more efficient process than regular methods. Also: it only produces positrons, no anti-protons. Anti-protons still have to be produced in particle accelerators, and lower efficiencies.

Originally posted by RFBurns
Do any of you realize what kind of power an anti-matter explosion would produce? Does anyone really think that creating an anti-matter bomb will be just some fancy type of nuke and wont affect your backyard?

Blow up half the damned planet why dont you!!! Cuz thats what will happen in an anti-matter expolosion.


Cheers!!!!



Yes, I do. And you very obviously don't. You can work it out with simple math (E=mc^2), and while it's powerful, you still need a lot of it to get real effects. The kind of power an anti-matter explosion can produce is determined by the amount of antimatter, and the amount of antimatter is determined by the amount of energy that goes into making it. Since even this improved process is extremely inefficient, it will take a lot of power for very little return.

It takes about a half gram of antimatter to equal the power of the bombs used on Hiroshima, a very small nuke by today's standards. That amount of antimatter would take about something like 25 to 50 quadrillion dollars to produce, and take perhaps 20-50 billion years. The actual bombs used on Hiroshima took just a few years and the equivalent of a few billion of today's dollars to research, invent, design, construct, and uitlize.

Frankly, if it weren't for the practical disadvantages in storing them, I'd rather everyone use antimatter bombs instead of nuclear bombs of corresponding size, because antimatter bombs produce less particle radiation. Lots more gamma rays, yes, but less particle radiation.


reply posted on 5-12-2008 @ 05:49 PM by mdiinican
reply to post by mdiinican


ADDENDUM: By "25 to 50 quadrillion dollars to produce, and take perhaps 20-50 billion years" I of course mean assuming we started today, with today's technology and energy prices, and continued that without change until we got the desired half-gram of antimatter. I'm sure we'll think of better methods in the near future, let alone in 20-50 billion years. it will still probably have a maximum efficiency of 50%, though.

Also: there isn't really any practical method of storing antihydrogen; usually we can only maintain a few million atoms of the stuff at any one time, using full production to supplant losses due to annihilation.
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