Sikon wrote:Since the firepower of the weapon would depend upon the energy delivered rather than the energy per individual photon, there is no clear reason to use even 1.5 MeV radiation. Indeed, with known technology, photons in the MeV range can be directed far less than even X-rays in the low keV range, so normally the obtainable range, focus, and concentration of the beam on the target would be less.
If penetration was the goal instead of range or raw firepower, a particle beam analogous to the more penetrating cosmic rays would penetrate more shielding. However, for your handgun example, high penetration might not be the goal. Rather, avoiding production of much secondary radiation could be paramount. The amount of secondary radiation required for the operator to have undesirable health risks is literally a number of orders of magnitude below the original beam energy immediately lethal to the target, especially considering repeated firings. Since 1.5 MeV to 2 MeV photons should still cause some pair production indirectly irradiating the operator, such is probably undesirable unless that amount is truely astronomically low compared to the original beam energy.
A lethal radiation gun could be an interesting and effective weapon if it could be practically built and safe for its operator. Yet there seems no benefit in having photons in the MeV range when you could just use X-rays in the keV range.
Yes, it was primarily Kuroneko's post that made me reconsider using such a beast for handheld weapons (the part about vacuum armor was just a very sick, sick joke).
http://www.ndt-ed.org/EducationResource ... uation.htm
Pair production (PP) can occur when the x-ray photon energy is greater than 1.02 MeV, but really only becomes significant at energies around 10 MeV. Pair production occurs when an electron and positron are created with the annihilation of the x-ray photon. Positrons are very short lived and disappear (positron annihilation) with the formation of two photons of 0.51 MeV energy. Pair production is of particular importance when high-energy photons pass through materials of a high atomic number.
Whoo...if I drop the output below 1 MeV, there goes even more of the cool factor of having a hand graser*, but it gains practicality as there go the deadly secondary emissions with it. However, 2 MeV, while high enough to produce this effect, doesn't look like it would be well below the "significant" threshold. Then again, as you say, if you're burning off the power cell on full automatic for some reason, such as being in the middle of a firefight, it probably becomes very significant.
*Actually, this is somewhat important to the way I'm telling the story, because it does somewhat satirize real life. The idea of "Look, I got a 1 MEGA electron volt hand graser" is analagous to the idiot who brags about his new " x-hundred super duper ultra magnum hunting rifle that's really powerful, has lots of muzzle energy, all kinds of knock-down power," and because it kicks like a mule he can't handle the recoil and as a result can't hit the broad side of a barn with it to begin with. Thus some obscenely high amount of energy
is necessary but largely as a cosmetic touch.
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