How difficult would it be to make high-power energy weapons undetectable?
Take, if you will, a sci-fi setting in which power is cheap and handheld energy weapons (blasters, lasers, plasma rifles, that sorta thing) are common. In this setting is an isolated community basically dedicated to stealth and assassination (think "ninjas in space").
Ostensibly, my space-ninjas favor traditional ninja weapons (shuriken, swords and the like) and ninja tricks over the energy weapons which are not only significantly more powerful but far easier to obtain, because of the stealth aspect: Any energy weapon which can generate and use enough power to be…well…an effective weapon, would basically be detectable by pretty much anyone with a mind to detect them. It would be like trying to sneak around with a giant neon sign flashing "← Here is a ninja".
They may be many things, but space-ninjas are not stupid. If they could still do their job and sneak around while using a blaster, they'd totally do it. Right now, I'm sorta handwaving this away as being logistically impossible: sure, we could make you a blaster that can't be detected, but it would require so much shielding that it would either (a) lose all portability or (b) end up prohibitively expensive. 477
And even then, it wouldn't help you when you decide to actually fire the thing.
But I'm not sure how realistic this is. It seems to me that due to being portable yet practical hand weapons in the first place, heavy shielding would already be a built-in necessity just to prevent the device from arcing electricity everywhere or sticking to every metal surface around when it's turned on. However, my knowledge of electromagnetism is pretty much limited to high school physics class and having watched a lot of Star Trek, which isn't really as helpful as it might seem.
I'm still researching exactly how the weapons would work, technology-wise, and since all worldbuilding to this point has focussed on the ninjas who plain don't (or shouldn't) use them it's not been a huge concern yet. I could easily just say that the plasma rifles are of necessity run off of a handwavium power cell — instantly detectable by any easily-produced handwavometer — and get the desired results (i.e. ninjas avoiding tech), but I would prefer to keep my handwavium within reasonable limits. For the purposes of this question, I'm less interested in the detectability of the hypothetical sci-fi power source and more about the detectability of any electrical device designed to draw and handle that much energy.
Assuming everything is basically powered by electricity, how viable would it be to have — and use — that much power portably without it producing enough of a distinguishable effect to instantly set off an alarm from any system designed to look for it? 477