First, Eclipse Phase has room temperature superconductors, so you're probably able to set up a strong magnetic field without continual power input. To detect the antimatter, you'd want to fire neutral particles (neutrons and neutrino bursts) through the object that would potentially have the contraband antimatter and watch for telltale signs of heat and generated particle emission.

I had a little discussion of this in my early adventure Think Before Asking: Antimatter detectors Antimatter, when stabilized and kept in a proper containment unit, is hard to detect. Most security scans look for the tell-tale signature of containment units but this only work when the unit passes through the scanner. A few scintillation detectors instead look for gamma photons with the specific energies of 938 MeV (the signature of proton-antiproton annihilation) and 511 KeV (electron-positron annihilation). Even a very good containment unit will have occasional annihilations. In space there are plenty of stray gammas but the signature gammas are specific for the presence of antimatter – if a detector gets a few flashes over a short span of time when it is not also detecting other cosmic ray activity, it can predict with good reliability the presence of sizeable amounts of antimatter within a few tens of meters. [Cost: Low] Basically, you look for photons with fairly particular energies. Subsequently I have learned that annihilation of protons is a far messier process: http://eclipsephase.com/comment/28439#comment-28439 So I would also look for muons and some pion decay gamma energies; same principle but more pattern matching going on. So, packets that are strongly shielded with superconductors (to avoid magnetic fields affecting the suspension of antimatter) and occur together with the wrong kind of gamma rays are suspect. Handle them with care.

uwtartarus wrote:

I am kind of a muggle when it comes to actual science like physics but wouldn't the containment require serious amounts of power which are not impossible but rather something that would blind those with electrical sense? Magnetism ~ Electrical fields and vice versa.

The amount of power needed doesn't have to be enormous: think of the energy needed to lift a small metal object with an electromagnet. And with superconductors you can have it circulate endlessly without losses. You likely want the device to be able to replenish itself for a *long* time anyway just for safety, and there are going to be several backup systems. However, there will not be any eternal fields. Superconductors do not let magnetism through (this is why they levitate in a magnetic field), and this makes it possible to shield the interior. You want that not just because it is annoying to have metal objects getting stuck to your WMD, but because you don't want external fields messing up your control.

Smokeskin wrote:

Wouldn't you only have antiprotons in your containment bottle? If there are positrons there, won't they combine with the antiprotons and form antihydrogen with neutral charge which can't be kept in by the magnetic field?

You can have either. If your detectors only detect antiprotons, then someone could theoretically make an antimatter store solely containing positrons which your detector wouldn't catch. You wouldn't want that.

You can magnetically contain monatomic anti-hydrogen. It's paramagnetic (not ferromagnetic) but you can still do it with a very powerful magnet. It's the same method you use to levitate a frog: http://en.wikipedia.org/wiki/Magnetic_levitation So you don't have to have anti-protons or positrons alone.