Hi everyone.
If there was no issue of cost, what technology could be achieved using antimatter?
Antimatter-catalysed weapons is one, nasty possibility;
a more peaceful application would be antimatter spacecraft propulsion
which can be divided into three main types,
the antimatter-catalysed fusion variety (where a small amount of antimatter provokes fusion in a fuel -most of the energy comes from the fusion)
the antimatter-electric variety (where antimatter produces enough energy ro run an ion drive, or similar)
and the antimatter thermal variety (where antimatter heats the propellant directly).
All of these produce large amounts of deadly radiation, and are inefficient because so much energy is lost in the form of intangible neutrinos. Even despite these drawbacks the amount of power obtainable from antimatter is so vast it would probably be worth using these systems assuming that the cost of anitimatter production was indeed no object.
It is difficult to imagine small scale applications for antimatter- you could try to run your car off it, and that would work - but like the nuclear car, the radiation from the drive would de dangerous, and the car would need lots of shielding- making it heavy to drive.
The question needs further explaining. Antimatter is expensive because our methods for making it are incredibly inefficient. If we’re assuming no issue of cost, then we must assume that we’re using different methods to make it. But then the answer depends on what those new methods are.
Well, cost of what? If you just mean production, not much. Antimatter is verrrry tricky stuff to store and transport, since of course you can’t have it touch any ordinary matter. But let us assume you mean low costs of production and storage and injection into some reactor where it annihilates with ordinary matter.
Well, now you have a way to store energy at absolutely phenomenal densities. You can carry milligrams and get to the Moon, for example.
But there are still grave problems, as mentioned above. Unlike fusion, which release most of its energy in the kinetic energy of its products (i.e. heat, roughly speaking), the energy released by matter-antimatter annihilation is released entirely as extremely penetrating and energetic gamma rays. Those are, themselves, very dangerous, but also difficult to capture and transform into some more useful form of energy (heat, chemical or electric potential).
I guess you might hope for efficient space propulsion, where shooting gamma rays out your butt is actually a pretty efficient rocket. But you have to think of some way to protect the crew compartment from this unholy blast of gammas going off just behind them. Ideally, you’d find some kind of gamma-ray mirror, which would not only protect them but also usefully double your thrust from the reaction.
Of course, a gamma ray mirror is kind of a theoretically implausible object, but so is an economical antimatter bottle, so we might as well lump them together in the project proposal. If the funding agency believes we can produce the one, there’s no reason they should balk at us producing both.
The problem with anti-matter is that you have to keep it totally isolated from ordinary matter or the two annihilate each other, with a release of energy in the form of radiation. In that sense, anti-matter could substitute virtually anywhere we might use nuclear fission/fusion power (as explained in the first response). You’d get more power per unit of fuel from antimatter, but the need to very carefully contain antimatter might cancel that benefit out.
Anti-matter can exist in its own elements and compounds. Maybe it would useful in some esoteric application to have an anti-sodium ion with a positive charge instead of a negative one… but it would otherwise have the same basic properties as ordinary sodium. You still have the problem of containing it - you can’t have it touching ordinary matter in any way. There’s no way to build some hybrid molecule from a mix of normal and anti- matter.
I suppose a cheap source of antimatter would be most useful to the high-energy physics world, but it would mostly be a matter of making it easier/cheaper to do things we can already do. It’s not like particle accelerators need large amounts of material; even grams of material would last you practically forever.
So… like Chronos says, I think the technology to make the antimatter would be of more interest than the antimatter itself.
Only if you’re just reacting electrons and positrons. If you’re reacting protons and neutrons with their antiparticles, then you’re initially going to get high-energy pions of various sorts. Those will in turn decay, so you’ll eventually get gammas, but you’ll also get even more neutrinos (which are even harder to do anything useful with). If you could get them to all come out in the same direction, gammas or neutrinos would either one work just fine for rocket propulsion… but getting them to do that will be a neat trick.
Well, scrith is opaque to 40% of neutrinos, perhaps if you could give it a mirror polish, it might reflect them. Of course, first you have to figure out how to make it.
At least for unmanned spacecraft, gamma radiation wouldn’t be nearly as much of an issue.
Although gamma radiation will not directly cause single event upsets or other effects if ionizing radiation, the interaction with other materials and emission of high energy electrons and ions due to the photoelectric effect will unless avionics are adequately shielded. And because the momentum of the production of gamma radiation photons (at least two, perhaps more) is a net zero, you have to produce charged pions which can be reacted by a magnetic field in order for them to do work. Unfortunately, even a proton-antiproton reaction, which produces pions, which rapidly decay to muons (which also decay) and electrons or positrons (which don’t) as well as various flavors of neutrinos and, ultimately, gamma rays (neutral pion decay, muon-anti-muon and positron-electron interactions) so relatively little of the momentum is available for a relatively short amount of time to provide impulse to a rocket. (That it is also moving a relativistic speed doesn’t help, either; basically, you’re going to need a “nozzle” that is several kilometers long to get significant momentum extraction.)
Antimatter isn’t of great practical use to us outside of basic physics research, positron emission tomography, and perhaps as a short-lived tracing material. It is not a great medium for energy storage or extraction, it’s a shitty fuel, and a potentially dangerous weapon if someone could produce enough of it to be useful.
Stranger
Granted, though I imagine shielding electronics and other sensitive equipment might be more practical and easier to do than for living beings?
What about using the burst of pure energy by annihilation as a way to propell the craft against reaction mass, rather than tossing out one hydrogen bomb after another ala something like Project Orion?
It’s still the same problem, but magnified: Now, instead of just needing to get the gammas (and neutrinos) to be absorbed or reflected by the butt of the ship, you also need to get them to be absorbed or reflected by the reaction mass. It might get results more immediately, but it’s also going to be more complicated and, in the long run, less efficient.