The Compleat Billy Chronicles (thanks to Zenpatista)

[altered]

Unlikely, those are less likely to have ionizing flux. (The gold standard would be photon or electron beams, neither of which are murderous if you aren't in the line of fire.)

If it's neutron beams, on the other hand, making it man portable is unlikely for entirely different reasons: it's sort of like if you tried to make an M40 recoilless rifle "man portable", in that you get maybe two shots and you're carrying four hundred pounds the entire time. Neutron sources will DEFINITELY cook your ass, but they're better for area denial, because neutron flux smashes through walls and causes elemental transmutation into VERY VERY nasty isotopes you don't ever want to be around. A single whoopsie creates a straight line of oh no that is certain to murder a civvy, directly or otherwise.

No, not man portable: this is far more likely to be vehicle mounted.

[altered]

And if it's gamma rays, do we even HAVE a source of strong gamma radiation that doesn't have a half-life measured in days AND is consistent enough to put inside of a laser? I don't think so: last I checked we can't even consistently produce X-ray radiation powerful enough for spectral coherence, which puts a damper on weaponizing it beyond about twenty meters.

[The Wizard Joseph]

I can only hope this is the sort of socially irresponsible I can hope to achieve by myself with sufficient hard work and lack of survival instinct.

On the other hand, there's a tiny but greater than zero chance they're onto something, and then I get everything I ever wanted.

I mean, once we get around that "insane level of radiation basically microwaving the operator" thing.

What if the answer is you don't. You topload the biological system to remain operationally functional for as long as possible, but all trips are one way attempts to radically alter the timeline. There's no return trip, and just maybe them jumping destroys this universe so failure is not an option. If they fail to sufficiently alter the timeline in a manner that prevents their jump from occurring the universe gets caught in a causation loop that cuts the timeline short forever.

It would be best to send highly trained and coordinated teams on major alteration missions, but the good news is subtlety is unnecessary and maybe even entirely undesirable.

[altered]

Stable time loops are stable because of the temporal conservation of mass. If you disrupt a stable time loop you end with permanent loss of mass energy (which can never happen and might destabilize the laws of physics depending) or permanent gain of mass energy (which can never happen and might destabilize the laws of physics in entirely different apocalyptic ways). This is entirely separate from the logical temporal paradoxes.

The only way time travel is possible is if you get stringy or go many-worlds, and in the many-worlds case there is so much MORE fun you can have than trying to create a fucking stable time loop just to fuck with it. Why, consider: in every Tucson reasonably close to our Tucson, there is a Howl in an arms manufacturing company. And in a significant fraction of those, he cackles and presses the big red "TEST FIRE" button and breaks down the walls between the worlds.

There is a very real chance of infinite Howls with infinite reality-crackers seeing each other and REALIZING WHAT IS HAPPENING.

Then things get really fun.

[The Johnny]

Relax guys, im pretty sure hes just making an improved microwave in which you can heat your food without having to worry about removing the tinfoil and metal utensils.

[Doktor Howl]

Stable time loops are stable because of the temporal conservation of mass. If you disrupt a stable time loop you end with permanent loss of mass energy (which can never happen and might destabilize the laws of physics depending) or permanent gain of mass energy (which can never happen and might destabilize the laws of physics in entirely different apocalyptic ways). This is entirely separate from the logical temporal paradoxes.

The only way time travel is possible is if you get stringy or go many-worlds, and in the many-worlds case there is so much MORE fun you can have than trying to create a fucking stable time loop just to fuck with it. Why, consider: in every Tucson reasonably close to our Tucson, there is a Howl in an arms manufacturing company. And in a significant fraction of those, he cackles and presses the big red "TEST FIRE" button and breaks down the walls between the worlds.

There is a very real chance of infinite Howls with infinite reality-crackers seeing each other and REALIZING WHAT IS HAPPENING.

Then things get really fun.

Look, if you pocket off mass from the universe, you're fine so long as you account for the mass (ie, bending the  bejesus out of localized space).  Physics doesn't mind, the universe does this all the time.

Also, you can disappear entirely leaving no mass or bent space behind, so long as you reappear at the same time you left (you can cheat conservation for about a femtosecond before the auditors show up, about the same amount of time it takes for an electron to orbit inside an atom.)

This may sound oddly specific. 

Time travel is for nerds.

[Doktor Howl]

And if it's gamma rays, do we even HAVE a source of strong gamma radiation that doesn't have a half-life measured in days AND is consistent enough to put inside of a laser? I don't think so: last I checked we can't even consistently produce X-ray radiation powerful enough for spectral coherence, which puts a damper on weaponizing it beyond about twenty meters.

That's Rube Goldberg stuff.  Why build an X-ray laser when you already have them?  And bollides?  There is nothing you can do with an x-ray laser that cannot be done more easily with a big honking chunk of mass moving at indecent speeds.

[chaotic neutral observer]

There is nothing you can do with an x-ray laser that cannot be done more easily with a big honking chunk of mass moving at indecent speeds.

It suddenly occurs to me that a Jedi Master would have no way to defend against even a WW1-era machine gun.  Maybe his precognition will let him block the first bullet, but there's no way he can wave that light sword fast enough to stop all of them.  Actually, a shotgun might be even better, since the bullets all fly at once.  When was the blunderbuss invented?  1700-something?

Anyway, if it's a beam weapon, it needs to have a better cost/lethality ratio than conventional firearms.  Within certain limits, anyway; I don't know if cost is that big of a deal for the American military.

Hmm, what else might leak radiation?  A nuclear-powered hoverboard?

[altered]

You have to remember the "missing reality" thing. Nuclear power doesn't knock chunks of the universe out.

[chaotic neutral observer]

I try not to think about what "knock divots out of our little corner of reality" might really mean.

[Doktor Howl]

I try not to think about what "knock divots out of our little corner of reality" might really mean.

It means SCIENCE! 

Also, I learned a new term:  Expended matter.  Basically, matter that has partially collapsed at the atomic level.  I don't really quite understand it yet.

To our knowledge, there's none in existence, but it could be a potential byproduct.  It would be a fantastic energy source, and also immediately deadly to life on contact with ANY amount of it.  Like one atom of it.

[altered]

Are you seriously talking about fucking with the strong force? Cause that's about all I can see ending in "expended matter". Also, if my memory serves, that's a path to truly horrible things, like quark matter (by which I mean quark matter that isn't bound into safe, clean baryonic subunits the way something nice and friendly like plutonium is...)

[Doktor Howl]

Are you seriously talking about fucking with the strong force? Cause that's about all I can see ending in "expended matter". Also, if my memory serves, that's a path to truly horrible things, like quark matter (by which I mean quark matter that isn't bound into safe, clean baryonic subunits the way something nice and friendly like plutonium is...)

I'm still reading, but yes.

I don't think I want to make any of this on the planet where I keep my stuff.

[minuspace]

So the positron beam goes over there.

[altered]

Are you seriously talking about fucking with the strong force? Cause that's about all I can see ending in "expended matter". Also, if my memory serves, that's a path to truly horrible things, like quark matter (by which I mean quark matter that isn't bound into safe, clean baryonic subunits the way something nice and friendly like plutonium is...)

I'm still reading, but yes.

I don't think I want to make any of this on the planet where I keep my stuff.

This is definitely one of those situations where if someone said "Tsar Bomba" I'd say "revise upward". Christ.

You need to check the person responsible for possession of an unlicensed Grin. You know the type.