Testing for antimatter explosion

[Enola Straight]

Suppose in the future someone manages to detonate an antimatter weapon of mass destruction.

Now I'm sure in the fallout of a fission device there is some isotope of cesium, and some kind of lithium residue in a fusion device fallout, but what telltale residue could be found in a M/AM detonation?

[Surlethe]

Look for lack of fission and fusion products and signs of a heavy gamma ray burst. That's all that springs to my mind.

[Kuroneko]

The neutrinos would be different, of course, but they're extremely difficult to detect. That's pretty much it, really--a lack of predicted fission or fusion products would be the most telling. There may be some trace transmutation of the surrounding atoms, which just might be high enough and different enough to be used as corroborating evidence (or it might not). For example, the most likely reaction path for proton/antiproton annihilation looks something like this: p + p' → π⁺ + π⁻ + π⁰ → μ⁺ + μ⁻ + 2γ + (ν's) → e⁻ + e⁺ + 2γ + (more ν's).
The pions are too short-lived to be significant, but the leptons are capable of reacting with the protons of other atomic nuclei and could potentially last long enough to do so. However, I don't know whether the rates of this sort of thing would be significantly different from what occurs in a nuclear or thermonuclear explosion.

[Lord of the Abyss]

As I recall, antimatter weapons wouldn't necessarily produce as sharp a shockwave as a nuclear weapon, depending on how fast the matter and antimatter mix. I also recall that one way that scientists can tell the difference between a blast caused by a volcano or chemical explosive and one by a meteorite or nuke, is that the latter two create something called "shocked quartz". Volcanoes and chemical explosives don't produce a sharp enough shockwave to produce the stuff; depending on design, a M/AM bomb might not either.

[Shroom Man 777]

Why would an AM bomb not make a sharp enough shockwave? Volcanoes and chemical explosives aren't as intense when compared to a meteorite or a nuke. I'd guess an AM bomb would be more along the lines of a meteor or a nuke rather than a volcano or a chemical explosive.

[Enola Straight]

I figure, post detonation residue would indicate what kind of enemy we were dealing with.

Atomic = terrorist group with good connections.
Hydrogen = due to the sheer size of the device, must be a major superpower to deliver.
Antimatter = extraterrestrial or future tech.

[phongn]

Fusion weapons aren't that big, you know. And why would an M/AM device imply future or alien technology?

[Lord of the Abyss]

Why would an AM bomb not make a sharp enough shockwave?

Because it's hard to make the matter and antimatter combine as fast as a nuclear detonation. As soon as the reaction starts, the matter around the antimatter tends to be blasted away, which slows the reaction. In a nuclear reaction, the explosion occurs because of a chain reaction inside the fissile material; by the time it begins exploding the process is done, not beginning like a M/AM reaction would be.

[FedRebel]

Antimatter = extraterrestrial or future tech.

...or the US, for research purposes a small amount of antimatter can and has been created in a particle accelerator.

[Sea Skimmer]

...or the US, for research purposes a small amount of antimatter can and has been created in a particle accelerator.

The European CERN research group also has created anti matter via particle accelerator. However total world anti matter production is measured in the very low millionths of a gram per year, and the cost of making even one gram would be hundreds of times the world gross domestic product. So basically, earth isn’t going to be building any anti matter weapons, now or ever.

A matter anti matter reaction would release a large fraction of all its energy in the form of neutrinos anyway, and since neutrinos pass through normal matter that means a big chunk of the energy will accomplish nothing in terms of destructive.