why are lasers better than neutral particle beams?

Admiral Valdemar · Post by **Admiral Valdemar** » 2003-01-17 03:02pm

kojikun wrote:Uh.. no exploding of the cities. o__o;

I was hoping you'd VAPE the whole county (Google if unsure) and put me out of my misery... of Yorkshiremen!

phongn · Post by **phongn** » 2003-01-17 07:30pm

Admiral Valdemar wrote:
phongn wrote:
Shrike wrote: ::hits head on desk::
*Keeps making phongn hit his head on desk*

Wheee!

::drops nuke on AV's formerlly-secret hideout::

Admiral Valdemar · Post by **Admiral Valdemar** » 2003-01-17 09:01pm

phongn wrote:
Admiral Valdemar wrote:
phongn wrote: *Keeps making phongn hit his head on desk*

Wheee!
::drops nuke on AV's formerlly-secret hideout::

*General Electric Type VI gimble mounted, all purpose CIWS pulsed-UV laser vapes nuke midfall*

kojikun · Post by **kojikun** » 2003-01-18 01:11am

change: im going to build a LinAc first and probably only. synchrotron radiation might be too great with a synchrotron. However, if I can minimise it i'll try a synch. It'll end up being a multi-LinAc device rather then a full toroidal, because getting the toroidal beam tube would be near impossible.

for the HV source i'm building a Van de Graff which will hopefully be rated near 250 kilovolts. The LinAc will have atleast one cavity (duh) so the minimum energy output would be 250 kilo electron volts. If I use two or maybe four cavities then I could get up to 1 mega electro volt. The synchrotron will get much higher energies because it wouldnt be constricted by length. I might get a few tens of millions of electron volts

This also depends on whether I can get the guide magnets strong enough. Magnet power might be my biggest problem.

Arrow · Post by **Arrow** » 2003-01-18 05:42pm

I would think that building a laser system that could put the same amout of enery on a target as a high powered NPB would be extremely expensive.

Admiral Valdemar · Post by **Admiral Valdemar** » 2003-01-18 05:46pm

Arrow Mk84 wrote:I would think that building a laser system that could put the same amout of enery on a target as a high powered NPB would be extremely expensive.

Depends on the type of laser it is. NPBs and CPBs are devastating due to their energy delivery, lasers can alter effects too depending on wavelength and so on.

jaeger115 · Post by **jaeger115** » 2003-01-18 06:29pm

Some people on this board say lasers are better. Others say the NPBs and CPBs are better. Prove that either is better, please.

Arrow · Post by **Arrow** » 2003-01-18 06:35pm

Just what is the highest speed that we can accelerate a particle too? I've heard its currently around .9c. Also, how much energy would those two grams have if they traveled at exactly .9c?

kojikun · Post by **kojikun** » 2003-01-18 07:59pm

Mikes relativity calc says that 2 grams of matter will require 2.329E+14 joules. Fermi Lab says that one electron volt equals 1.602E-19 joules, so one joule equals 0.6242E+19 electron volts. 2 grams at 0.9c require 1.454E+33 electron volts. Currently, the worlds most powerful particle accelerator can produce 1E+12 electron volts, so even the most powerful particle accelerator, the Fermi Lab Tevatron, is 21 orders of magnitude too weak.

aerius · Post by **aerius** » 2003-01-18 09:20pm

Well, we already have Petawatt lasers which can blow atoms apart among other things, so I don't see any advantages for a neutral particle beam. Here's link to the Petawatt Laser they have over at Lawrence Livermore Labs, and a few choice excerpts of what it can do. So much for the advantages of particle beams.

"The Petawatt laser achieved a focused power density approaching 10^21 W/cm2 (almost a sextillion watts of energy concentrated on a square centimeter) and an energy density of 30 billion joules in a cubic centimeter-far exceeding the energy density inside stars. The associated electric fields are so strong-approximately a thousand times stronger than those that bind electrons to atomic nuclei-that they strip electrons off atoms and accelerate them to relativistic velocity (that is, comparable to the speed of light)."

"The intense beam of Livermore's Petawatt laser was powerful enough to break up atoms by causing reactions in their nuclei. Accelerated by the laser, electrons traveling at nearly the speed of light collided with nuclei in a gold foil target, producing gamma rays that knocked out some of the neutrons from other gold nuclei and caused the gold to decay into elements such as platinum. Gamma rays also zoomed in on a layer of uranium sitting behind the gold and split uranium nuclei into lighter elements. Before the Petawatt, all of these effects had been solely in the domain of particle accelerators or nuclear reactors.
Accelerated to energies exceeding 100 megaelectronvolts, the electrons in the gold targets produced high-energy x rays. These in turn decayed into pairs of electrons and their antimatter counterparts, positrons, in such large numbers as to possibly generate an electron-positron plasma, never before created in the laboratory. An intense beam of protons also turned up. Not only was the Petawatt the most powerful laser in the world, but, unexpectedly, it also was a powerful ion accelerator."

jaeger115 · Post by **jaeger115** » 2003-01-18 09:54pm

Well, we already have Petawatt lasers which can blow atoms apart among other things, so I don't see any advantages for a neutral particle beam. Here's link to the Petawatt Laser they have over at Lawrence Livermore Labs, and a few choice excerpts of what it can do. So much for the advantages of particle beams.

Well, I've heard that lasers can be negated by severe weather and cold plasma. Still looks good.

Arrow · Post by **Arrow** » 2003-01-18 09:55pm

From the same site aerius linked to:

Livermore's Petawatt laser operated for three years, until its last shot was fired on May 27, 1999. At full energy of about 680 joules, the shots delivered more than a quadrillion watts (or petawatt, which equals 1015 watts) of power, exceeding the entire electrical generating capacity of the U.S. by more than 1,200 times. But the Petawatt's shots lasted for just a fleeting moment-less than a trillionth of a second, or 440 femtoseconds to be precise.
The Petawatt laser was developed originally to test the fast ignition path to inertial confinement fusion in the ongoing attempt to ignite a pellet of hydrogen fuel and harness the energy that powers the sun. The power of the Petawatt also opened up entirely new physical regimes to study. Now scientists can use lasers, not just particle accelerators, to study high-energy-density physics and the fundamental properties of matter. They may also be able to recreate in the laboratory the energized plasmas around black holes and neutron stars for astrophysical research.

Ok, so they fired off 680 joules of enery in a fraction of second. That's not going to much to a futuristic warship. I think NPBs will be the way to go; building one of these things that is usable as weapon would probably eat way more energy that any power system we could conceivably produce in the next thousand years would generate. These guys just hyped up their little device (much like McDonald's fast food...)

kojikun · Post by **kojikun** » 2003-01-18 10:07pm

680 joules? thats IT? I've built capacitors capable of releasing more.

jaeger115 · Post by **jaeger115** » 2003-01-18 10:10pm

I've built capacitors capable of releasing more.

You've built capacitors? Are you an electrical engineer?

Arrow · Post by **Arrow** » 2003-01-18 10:13pm

That's it. Third or fourth paragraph down. Hell, its not even a decent way to cook a steak!

aerius · Post by **aerius** » 2003-01-18 10:31pm

Arrow Mk84 wrote:Ok, so they fired off 680 joules of enery in a fraction of second. That's not going to much to a futuristic warship. I think NPBs will be the way to go; building one of these things that is usable as weapon would probably eat way more energy that any power system we could conceivably produce in the next thousand years would generate. These guys just hyped up their little device (much like McDonald's fast food...)

Right, and what can a current NPB do? As far as I know they work great for heating up plasma in fusion reactors but that's about it. And in case you're interested making a NPB takes way more energy than making a laser. Power generation is still going to be an issue there, unless you claim that NPB are several orders of magnitude more effective than lasers. The fact is we already have laser technology that can be built into viable weapons, and the pulse-chirp technology of the Petawatt laser can be used to greatly increase power. Think pulsed laser beams. NPB weapons remain a pipedream on some person's drawing board.

kojikun · Post by **kojikun** » 2003-01-18 11:19pm

jaeger: no more then most people here. caps are simple to make: plate insulator plate. ofcourse you can get fancy with electrolytes and such too.

aerius: current NPBs can speed particles to 99.9999PSL, current NPBs can create antimatter, current NPBs can produce enough radiation to make hiroshima look like a microwave leak, current NPBs can liquify metal in fantastically small amounts of time.

Modern lasers can do similar things, but your petawatt laser is shit. It releases less energy then a cough (not literally). The only reason its so increadibly powerful is the duration of the pulse.

Admiral Valdemar · Post by **Admiral Valdemar** » 2003-01-18 11:22pm

NPBs can also be used in a variety of other different functions too, not that lasers don't have brilliant side effects like infrasonic vibrations as the material is hit by similar frequency EM energy or the nice clouds of plasma from vaped material.

Arrow · Post by **Arrow** » 2003-01-19 08:12am

Futhermore, we can already power a particle accelerator. An NPB capable of few gigatons would require more energy than we currently possess, but it is with in the realm of possibility. For the petawatt laser to be a weapon, it needs FAR FAR more energy than 680 joules; hell, to even work as you've advertised it needs more energy than the entire world has ever produced! An I'm willing to bet that our material science can keep this thing from melting itself. When it comes to destruction, particle beams will simply own lasers.

Arrow · Post by **Arrow** » 2003-01-19 08:17am

An I'm willing to bet that our material science can keep this thing from melting itself.

That should be can't, not can.

Admiral Valdemar · Post by **Admiral Valdemar** » 2003-01-19 11:03am

Arrow Mk84 wrote:
An I'm willing to bet that our material science can keep this thing from melting itself.
That should be can't, not can.

True, no amount of fancy mettallurgy or polymer materials or ceramics will stop a PBC from exploding the structure due to the way it does so. A laser is different though.

aerius · Post by **aerius** » 2003-01-19 11:36am

kojikun wrote:aerius: current NPBs can speed particles to 99.9999PSL, current NPBs can create antimatter, current NPBs can produce enough radiation to make hiroshima look like a microwave leak, current NPBs can liquify metal in fantastically small amounts of time.

I've done some looking around and I honestly don't know where you're getting these facts from. From what I've seen the most powerful NPB so far puts out about 10MW of power for about 10 seconds or so. This is the NPB used for heating the plasma in the JT-60 fusion reactor. I've also seen that they can produce high intensity x-rays by putting the beams through a wiggler device, but like the laser it's only for short picosecond pulses. So far I haven't been able to find anything about NPB burning holes through metal or anything like that, so if you point me in the right direction I'll be more than willing to re-evaluate my opinion.

ClaysGhost · Post by **ClaysGhost** » 2003-01-20 06:43am

Let's take the Large Hadron Collider (although it's a CPB, there is no spectacularly different physics operating in NPBs during beam preparation). It is designed to produce beam energies of about 330MJ total (individual particles have energies of up to 7TeV, yes, but the total energy stored is not enormous). It will take about 4 minutes to charge the ring up to full power (the particles have to be accelerated from an injected energy of about 450GeV), and the best power output you could expect is about 1MW. The device itself is large and massive, and beams of this magnitude are sometimes subject to instability and must be dumped, even with superconducting magnets and computer control. The particles radiate energy each time round the loop, and this energy must be replenished in addition to charging in the first place. Note that it would take over 5 minutes to discharge 330MJ into a target at a rate of 1MW.

kojikun · Post by **kojikun** » 2003-01-20 12:07pm

I've done some looking around and I honestly don't know where you're getting these facts from. From what I've seen the most powerful NPB so far puts out about 10MW of power for about 10 seconds or so. This is the NPB used for heating the plasma in the JT-60 fusion reactor. I've also seen that they can produce high intensity x-rays by putting the beams through a wiggler device, but like the laser it's only for short picosecond pulses. So far I haven't been able to find anything about NPB burning holes through metal or anything like that, so if you point me in the right direction I'll be more than willing to re-evaluate my opinion.

You're forgetting that power and energy are not the same. The petawatt laser may produce billions more watts, but its only putting out 680 joules. The gravitational potential energy of a 80 kilogram person at a heigh of 3 metres is 2,300 joules, if my knowledge about GPE is correct. the petawatt laser would be able to put the person 0.86 metres into the air in a fraction of a second, or boil a few gallons of water instantly, but once those 680 joules are gone, poof, thats it, no more laser.

As for the Near light speed particles etc:

Fermilab has gotten Tevatro particles up to 99.999954% c: http://www.fnal.gov/pub/inquiring/quest ... opart.html

Fermi Lab plans to mass produce antimatter at a rate of 18e10 antiprotons per hour, topping their previous 12.4e10 per hour best in 2001: http://www.fnal.gov/pub/inquiring/quest ... rprod.html

As for radiation, I cant give you a precise link. I was exxagerating ofcourse when it comes to the level of radiation, but let me put it this way: an XRay tube at hospital uses 30KeV to produce its XRays. The Tevatron uses 1,000,000,000 KeV.

Melting targets with120GeV during anti-matter production: "The drum is rotated quickly to prevent the beam from hitting the same spot over and over. This prevents the distruction of the target." - http://www.fnal.gov/pub/inquiring/questions/jackie.html

Arrow · Post by **Arrow** » 2003-01-20 12:45pm

Well I think that conclusively smacks down the laser for blasting things apart! Thanks for the info kojikun.