-1
$\begingroup$

I saw this on an interesting reddit and wondered if you could replace all the handwave blaster weapons in sci fi with particle accelerator rifles or pistols and what tech would be required to make this possible and what advantages would this give to militaries. https://www.reddit.com/r/scifi/comments/43wtl7/particle_beams_the_ultimate_hard_scifi_weapon/

I'd like good semi hard sci fi answers with somewhat good reasearch behind them. Please do not tell me it is not possible, but rather tell me what technologies would be needed to make it possible, these can . EDIT:For a possible power source, maybe a sort of diamond battery( using synthetic diamonds, real ones are too expensive) or even multiple layers of paper thin graphene super capacitors, or even the new li-ion batteries with graphite anodes made by the university of arizona.

$\endgroup$
  • 8
    $\begingroup$ What if I tell you it is possible but would make terribly inefficient weapons? Like hitting people with wet noodles? $\endgroup$ – A. C. A. C. Feb 26 '18 at 20:48
  • 2
    $\begingroup$ Hey! Have you ever been slapped with a pool noodle? Those things hurt! Jokes aside, take a look at stuff like coil guns, which accelerate particles in the sense of 'clumps of matter' $\endgroup$ – Jakob Lovern Feb 26 '18 at 20:51
  • 2
    $\begingroup$ And as a corollary on Jakob Lovern's comment: just about every weapon other than sticks, swords, and pikes involves some sort of "particle accelerator" $\endgroup$ – sdfgeoff Feb 26 '18 at 20:54
  • 12
    $\begingroup$ "Please do not tell me it is not possible" — if you really want research behind answers, you need to drop this requirement. There are only 3 options: does not work, ignore science, shooter dies first. $\endgroup$ – Mołot Feb 26 '18 at 21:01
  • $\begingroup$ Yes thank you for the input on my question I will keep it in mind. $\endgroup$ – Efialtes Feb 26 '18 at 22:38
6
$\begingroup$

No, for a number of reasons.

  • gross inefficiency.
  • charged particles are easily deflected by magnetic fields
  • charged particles do not travel far at all in air

Of course, if we're talking large enough particles - say, the size of a bullet... but that's cheating.

You might have a weapon using "particle acceleration" if the accelerated particles aren't the energy delivery component (as said above and in @sdfgeoff's excellent answer, if they are you're left with too much bang required for not enough buck).

You can accelerate particles in a handy, shielded, portable vacuum, and have them brake hard against a variety of targets. You get all kinds of radiation and unaccelerated (but often fast enough) particles of several types.

So you can get X rays, several kinds of brehmsstrahlung, even neutrons. Neutron activation and the appropriate isotope gives access to a wide menu of gamma rays.

You don't get a gun, but a fancy handheld assassination weapon is somewhat possible.

Example

With sufficiently strong insulators and power supply, you can further reduce this gadget so that it's no bigger than two fists.

enter image description here

At the same time, it can produce a significant neutron flux; if you put it into a sealed container full of deuterium, it will produce a remarkable neutron flux. Place it somewhere the victim may be exposed - the radiation penetrates easily a wall - and the poor guy is started on the road to several nasty kinds of cancer.

Example

Forget neutrons, accelerate electrons with very high voltages so that they smash against a suitable target at an angle. A predictably shaped cone of ionizing radiation is generated.

enter image description here

With enough current, which requires more advanced technology to manufacture the gadget, you can have the victim fall ill within a few minutes, and die within days of acute radiation sickness.

$\endgroup$
  • $\begingroup$ Thank you what would this assaination weapon theoretically look like or how do you estimate it would work? $\endgroup$ – Efialtes Feb 26 '18 at 22:41
3
$\begingroup$

What tech would be needed? Extremely good power sources.

The muzzle energy of a 0.45 pistol is around 560 joules per shot. An AA battery contains 12,000 joules. Or enough energy for about 20 shots under ideal situations. However, with every mass-based weapon, at least 50% of the energy goes into recoil, and as soon as you introduce the circuitry of a typical coil-gun, you're even lower. This guy measured 2-3% effective efficiency from stored->projectile, so not even the charging. Now if 12,000 joules is all used in one shot at 2% efficiency, we've gone down from a .45 round to a .22 round. Eh, maybe use a lithium cell instead of an alkaline!

Even this is slightly ideal because an AA battery has less capacity at higher currents, so if you want a good refire rate, you'll need more batteries for the same output energy. But at this scale, it's at least feasible. A particle-beam pistol could be a viable weapon. (Note: it is hard to actually do this energy conversion. Coil guns typically aren't run on a single AA battery even if they only output energy in the 1-2Kj region)

Hold on, I asked about particle accelerators and you're talking about coil guns and pistols
Coil guns could be seen as a simpler and slightly more ideal form of particle accelerator. You put all your energy into accelerating the projectile. In a particle accelerator, you first have to ionise it. The projectiles travel faster, but the energy dealt on impact determines the damage done.


Now let's talk explosives. 1kg of tnt is equivalent to 4 million joules of energy. An aim-9 sidewinder missile's warhead weighs 9kg, and I'm willing to be it's got more than tnt inside it. But let's just assume that our aim-9 missile can output some 40Mj of destruction. Allowing for our 2% efficiency from earlier, we need an electrical source providing 20Tj of energy to deal the same amount of damage. The engine from a 777 airliner outputs 83,164 kW, so to fire our weapon we have to be running that airliner engine for around 67 hours. An airliner burns tonnes of fuel per hour. Needless to say, the extra energy required to manoeuvre those tonnes of fuel vs carrying 10kg of high explosive?

So how about nuclear reactors then? It's very hard to estimate how heavy a reactor is (and in space, it's all about how much it weighs). The RTG's flown on existing spacecraft are measured in the 100's of watts, so you'll be charging your guns for years. However, if we have a pair of nimitz's nuclear reactors (550Mw), then we can squeeze off a shot every twenty seconds. Still, two A4w reactors aren't light-weight, and one shot every 20 seconds is pretty pitiful. In short: you can stock a lot of missiles for the same mass.


So if you can hand-wave a good powersource that isn't more destructive by itself, then you can have your particle guns. (Is a fusion reactor powered particle accelerator more destructive than a fusion warhead? How about an antimatter reactor vs antimatter warhead?)

So where might a particle accelerator be useable even on the large scale? A large space station will have several large reactors powering it's internal systems (eg heating). In a period of combat, the life support can be turned off (everyone get's into their spacesuits), and they power up some particle accelerators.

$\endgroup$
  • 4
    $\begingroup$ "At least 50% of the energy goes into recoil": nope. Conservation of momentum means that the momentum of the projectile is equal to the opposed momentum of the gun. If the projectile is 100 times lighter than the gun it follows that its kinetic energy is 100 times larger than the gun's, because while momentum is proportional with velocity, energy is proportional with the square of velocity. $\endgroup$ – AlexP Feb 26 '18 at 22:46
  • $\begingroup$ For space battles, I'd take a light speed laser any day. For one thing, most particles are charged (positive or negative). After a few shots, your target gains a charge and no repels further shots. $\endgroup$ – ShadoCat Feb 27 '18 at 0:07
  • $\begingroup$ What about particles interacting with the air just outside muzzle?.. $\endgroup$ – Mołot Feb 27 '18 at 8:25

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.