why are lasers better than neutral particle beams?

aerius · Post by **aerius** » 2003-01-20 11:40pm

kojikun wrote:::holds up a mirror and blinds aerius:: You forget that industrial lasers need to be directed and to do this they use mirrors. Chrome coat your ship and your 12kW laser is useless.

actually kind of makes you wonder why the STARWARS laser program will work, since chrome coating a missile would be simple.

That chrome coating will only work for certain wavelengths of light, and even then it's not 100% effective. Mirrors can only reflect about 95% of the light falling on them, with a 20kW laser that works out to about 1kW that's not getting bounced back, now remember the part about how 10W was more than enough to burn through metal? The reason the mirrors in the laser don't burn up is because they're liquid cooled and made from far more reflective materials. Now if you're going to put an optical grade chrome plating on your ship and have the entire thing liquid cooled inside and out, it might just survive a laser hit, might.

kojikun · Post by **kojikun** » 2003-01-20 11:43pm

well shit, if it means being blown up youre damn right theyll liquid cool the fucking hull!

besides, your FEL was not a typical laser, it was powered BY A PARTICLE ACCELERATOR. Your biggest baddest weapon relies on MINE to work. And not even a synchrotron.

ClaysGhost · Post by **ClaysGhost** » 2003-01-21 05:16am

Graeme Dice wrote:
ClaysGhost wrote:Unfortunately, isolating the superconductors will go by percentages, and you'll end up with a system in which most of the energy goes into the superconductors because the accelerator is so big (to minimise the exposure of the superconductors) that the magnetic fields have to be enormously powerful.
Saying that "most of the energy goes into the superconductors" is meaningless. Superconducting magnets require no energy input to maintain their magnetic field, except when energy is removed by some external action. In this case, that would be the acceleration of the particles.

Larger magnets will require more energy to set up the field, and require a far larger cooling reservoir as well. If even 0.01% of a gigatonne level beam were to impinge on the magnets, you will have no more superconduction and no more field (and at that level, probably no more magnet, but that's incidental).

ClaysGhost · Post by **ClaysGhost** » 2003-01-21 05:37am

kojikun wrote:
True, but linear accelerators of any significant power such as SLAC are well over a mile long, and you can't shrink them down without seriously degrading their power.
quite correct. But small Synchrotrons could do similar things and not need to be as long. The Tev is a mere 4 miles around. It's smaller accelerators are quite powerful however. I'm looking around for energy levels right now :p

Will you make up your mind? You say that examining synchrotrons from a weapons perspective is pointless, because you'll use a linac. Now you're back to the synchrotron, and something four miles in circumference does not merit being called a "mere" anything.

Quite fixating on the 680 joule figure, you're acting as if it somehow makes lasers impotent.
It does if thats all the laser puts out.

You're ignoring the industrial cutting lasers, military lasers, mid-range research lasers, and the rest. I wonder why.

I put the link to the Petawatt laser so you can see the effects that a high power laser will have if we get around to building one that can fire longer pulses or operate in continuous beam mode. The point being a laser will act a lot like a particle beam at PW range power levels. Let's put it this way, a mere 10W laser can burn holes through 1/8" ceramics in under 10 seconds and metal in even less time, and we already have 20kW continuous beam cutting & welding lasers being used in industry. References provided here. By the way, a 20kW laser is about the size of a car, I could put one in a small rental truck and drive around blowing up cars by burning through them to their gas tanks.
We're not talking about continuous beams, we're talking about a 680 joule petawatt laser. No shit constant power lasers can burn through things. And if it does burn through ceramic with only 10 watts of power, I want to buy one immediately

Pulse lasers are perfectly capable of cutting through materials, and are widely used in industrial applications for just that purpose as you can establish with a simple google search. Higher power enables you to cut thicker metal (and cut it faster), and pulsed lasers are capable of providing far higher power levels than beam lasers. Presumably you're just ignoring the post where I noted that the petawatt laser we've discussed would only have to increase the energy it transferred by a factor of 10^5 to match the energy delivered in five minutes (a factor that you also continue to ignore; what target is going to sit still for five minutes!?!) by the LHC, but the LHC would have to ramp its power output up by a factor of 10^9 to match that laser.

ClaysGhost · Post by **ClaysGhost** » 2003-01-21 06:19am

aerius wrote:By the way, I decided to work out how much energy a linear accelerator uses and the energy of the final beam. Using the SLAC (Stanford Linear Accelerator & Collider) which can be referenced on the web, it uses about 30-40MW of power. This is used to accelerate bunches of about 10^10 electrons to near light speed, and only a few bunches can be accelerated at a time. Let's be generous and assume a bunch is accelerated to 99.99999% of lightspeed. That gives a relativistic energy of just over 100J. From the info I've found so far, they can accelerate about 120 bunches/second, giving a final energy of 12kJ/s, or 12kW for the particle beam. Efficiency = input power/output power, giving an efficiency for SLAC of 0.04% at best. Compare that to an industrial 20kW CO2 laser that has about a 25-30% efficiency.

So that's see here, a 12kW laser will use 48kW at worst, compared to 30MW at best for a particle beam. For an equivalent output power the particle beam will need 625 times the input power of a laser. So much for your high powered particle beam fantasies. Still think you'll be using particle beams for your big main weapons?

Maybe SLAC is inefficient. Let's compare it to the Large Electron-Position collider. According to CERN's website, it used on average 65MW of electrical power in typical operation. According to the website again, "good" conditions result in a beam power of 0.645MW, so just about 1% efficient. I'd say that NPB weapons have far more to prove regarding efficiency than lasers do.

well shit, if it means being blown up youre damn right theyll liquid cool the fucking hull!

Ok, so you really have parted company with sanity. Quite what use a cooled spacecraft with a great big hole in the side (since cooling will not prevent laser damage) is to anyone, I have no idea.

... besides, your FEL was not a typical laser, it was powered BY A PARTICLE ACCELERATOR.

FEL are "typical lasers" in research institutes undertaking that kind of materials research. Typical lasers in industry are C02. Typical lasers in communications are semiconductors. Flexible beast, the laser, and most lasers can operate pulsed. The FEL is valuable for its "tuning" ability.

aerius · Post by **aerius** » 2003-01-21 10:15am

kojikun wrote:besides, your FEL was not a typical laser, it was powered BY A PARTICLE ACCELERATOR. Your biggest baddest weapon relies on MINE to work. And not even a synchrotron.

I don't think you get the point, any 10W laser can burn through metal, doesn't matter if it's a CO2 laser, a diode laser, or a FEL. And since you don't seem to be paying attention, the FEL puts out a peak of 1720W, which is far less than a 20kW industrial laser. It's not the "biggest baddest" laser by any means, it's a concept that still in development that has unique properties such as a tunable wavelength that other lasers do not. Quit trying to take things out of context.

kojikun · Post by **kojikun** » 2003-01-21 01:45pm

Will you make up your mind? You say that examining synchrotrons from a weapons perspective is pointless, because you'll use a linac. Now you're back to the synchrotron, and something four miles in circumference does not merit being called a "mere" anything.

the TEVATRON is 4 miles around, not every synchro on the planet.

You're ignoring the industrial cutting lasers, military lasers, mid-range research lasers, and the rest. I wonder why.

Perhaps because they put out 20kW continuous for a substantial period of time and can barely manage to cut through SHEET METAL?

Pulse lasers are perfectly capable of cutting through materials, and are widely used in industrial applications for just that purpose as you can establish with a simple google search. Higher power enables you to cut thicker metal (and cut it faster), and pulsed lasers are capable of providing far higher power levels than beam lasers. Presumably you're just ignoring the post where I noted that the petawatt laser we've discussed would only have to increase the energy it transferred by a factor of 10^5 to match the energy delivered in five minutes (a factor that you also continue to ignore; what target is going to sit still for five minutes!?!) by the LHC, but the LHC would have to ramp its power output up by a factor of 10^9 to match that laser.

Noone said pulse lasers can't. I said a 680J 1PW laser cannot. Perhaps you're ignoring the fact that in order to cut through sheet metal with an industrial laser you need many KW of power. I think it comes down to method of energy transfer. Like I said, you can reflect lasers but you cant reflect NPBs. You think its hard? I guess the military wont be building laser turrets then, since obviously the directing mirrors wont work. Oh wait, they do.

FEL are "typical lasers" in research institutes undertaking that kind of materials research. Typical lasers in industry are C02. Typical lasers in communications are semiconductors. Flexible beast, the laser, and most lasers can operate pulsed. The FEL is valuable for its "tuning" ability.

And that changes the fact that it produces less power then the LinAc that powers it how? You and Aerius are both forgetting that the FEL LinAc produces more power then the FEL itself! The fell can bore through metal, but the LinAc can do it FASTER then the FEL.

I don't think you get the point, any 10W laser can burn through metal, doesn't matter if it's a CO2 laser, a diode laser, or a FEL. And since you don't seem to be paying attention, the FEL puts out a peak of 1720W, which is far less than a 20kW industrial laser. It's not the "biggest baddest" laser by any means, it's a concept that still in development that has unique properties such as a tunable wavelength that other lasers do not. Quit trying to take things out of context.

I dont think you get the point, your FEL requires more energy then you claim it does. The LinAc that powers it must provide the power for the FEL. The LinAc itself could do the burning.

ClaysGhost · Post by **ClaysGhost** » 2003-01-22 06:26am

kojikun wrote:
Will you make up your mind? You say that examining synchrotrons from a weapons perspective is pointless, because you'll use a linac. Now you're back to the synchrotron, and something four miles in circumference does not merit being called a "mere" anything.
the TEVATRON is 4 miles around, not every synchro on the planet.

1. You've answered only one point in that paragraph.
2. And what you have answered, you've misinterpreted. You'll note that I never said that every synchrotron is 4 miles in circumference.
3. So which is it to be? Linacs or synchrotrons?

You're ignoring the industrial cutting lasers, military lasers, mid-range research lasers, and the rest. I wonder why.
Perhaps because they put out 20kW continuous for a substantial period of time and can barely manage to cut through SHEET METAL?

Rubbish. A 2.2kW industrial cutting laser can cut stainless (0.16" thick) at a feed rate of over 2 inches per second, and sales of such low power lasers are dropping off nowadays because higher powers (6kW) are becoming popular. A 6kW laser can cut 16mm thick steel at a feed rate of an inch per second. Pulsed lasers are also used for cutting, a fact that you seem determined to ignore. Lasers have been turned into anti-missile weapons, another fact that you don't seem to like. Particle accelerators are not used for high-speed industrial metal cutting, and do not cut through the accelerator target but heat it, a process that the target can survive merely by rotating!

Until you produce an example of an in-service particle beam that accomplishes more than the examples you have so far stated, which have been uniformly of moderate power, long recharge time, huge size, large power consumption and low efficiency (you trumpet lasers having 20-30% efficiency as a disaster, but for some reason a particle weapon having an efficiency ~ 1% seems perfectly fine to you) and only transfer significant amounts of energy if the target is willing to sit still in the accelerator tube for minutes, I don't think your "facts" as to why NPBs are superior weapons stand up.

Noone said pulse lasers can't. I said a 680J 1PW laser cannot. Perhaps you're ignoring the fact that in order to cut through sheet metal with an industrial laser you need many KW of power. I think it comes down to method of energy transfer. Like I said, you can reflect lasers but you cant reflect NPBs. You think its hard? I guess the military wont be building laser turrets then, since obviously the directing mirrors wont work. Oh wait, they do.

1. Nobody has any difficulty producing kW levels of power. Perhaps you are the one confusing energy with power - your complaint up to now has centred on the 680J figure for Vulcan. Your accelerators are uniformly of MW level and produce mainly heating, which a target can survive (as you state) by rotating. A MW class laser has been used to blow up stressed ICBM stages before today.

2. "I said a 680J 1PW laser cannot" ... "to cut through sheet metal ... you need many kW of power". As I understand it, PW > kW, by a factor of 10^12. 2kW is sufficient to give stainless steel a hard time. 2kW is not a lot of power.

3. If lasers could be reflected trivially by targets, the military would not build laser weapons at all. Oh wait, they do. You are not going to get a sufficiently resilient and reflective coating on an object that has to undertake any sort of existence in the real world, not by orders of magnitude, and you are certainly not going to get one that preserves reflectivity over more than a narrow wavelength band. Ever seen a lens designed for use in IR? Ever seen a mirror designed for use with X-rays?

4. Exactly why do you think that all is quiet on the NPB front as regards the military applications? Maybe they misunderstood the weapons potential of bulky, massive, inefficient particle beam accelerators. Maybe.

FEL are "typical lasers" in research institutes undertaking that kind of materials research. Typical lasers in industry are C02. Typical lasers in communications are semiconductors. Flexible beast, the laser, and most lasers can operate pulsed. The FEL is valuable for its "tuning" ability.
And that changes the fact that it produces less power then the LinAc that powers it how? You and Aerius are both forgetting that the FEL LinAc produces more power then the FEL itself! The fell can bore through metal, but the LinAc can do it FASTER then the FEL.

FELs have uniquely poor efficiency, almost as poor as the particle beam injector stage itself, which is a good reason why they're confined to reasearch facilities. Fortunately, there are plenty of laser types listed in that statement that you've ignored.

I dont think you get the point, your FEL requires more energy then you claim it does. The LinAc that powers it must provide the power for the FEL. The LinAc itself could do the burning.

After some research, it turns out that the petawatt laser in RAL is not a FEL anyway, embarrasingly enough (for me, since I thought it was a FEL). It's a neodymium-glass laser (solid gain medium). And as stated, it is not "the biggest baddest laser"; it's not optimised to cut through metal or anything like that. It is optimised to produce interesting insights into the properties of materials when exposed to high intensity light. As for the linac, I expect it could heat a target.

His Divine Shadow · Post by **His Divine Shadow** » 2003-01-22 06:55am

ClaysGhost wrote:Rubbish. A 2.2kW industrial cutting laser can cut stainless (0.16" thick) at a feed rate of over 2 inches per second, and sales of such low power lasers are dropping off nowadays because higher powers (6kW) are becoming popular. A 6kW laser can cut 16mm thick steel at a feed rate of an inch per second. Pulsed lasers are also used for cutting

Where can I buy these lasers! How big are they? Will they fit in my hand?

Admiral Valdemar · Post by **Admiral Valdemar** » 2003-01-22 07:19am

His Divine Shadow wrote:
ClaysGhost wrote:Rubbish. A 2.2kW industrial cutting laser can cut stainless (0.16" thick) at a feed rate of over 2 inches per second, and sales of such low power lasers are dropping off nowadays because higher powers (6kW) are becoming popular. A 6kW laser can cut 16mm thick steel at a feed rate of an inch per second. Pulsed lasers are also used for cutting
Where can I buy these lasers! How big are they? Will they fit in my hand?

*Forklift truck drops a ton of complex optics and power generators on HDS*

That's our "Mini-Menace" range. Quite small, eh?

Arrow · Post by **Arrow** » 2003-01-22 08:13am

2. "I said a 680J 1PW laser cannot" ... "to cut through sheet metal ... you need many kW of power". As I understand it, PW > kW, by a factor of 10^12. 2kW is sufficient to give stainless steel a hard time. 2kW is not a lot of power.

That PW laser is absolutely useless! It only uses 680J. This means that the duration of the beam is only 0.000000000000000068 seconds! This absolutely useless for any military appilication. Get over the damn PW laser, its not that great.

Particle accelerators are not used for high-speed industrial metal cutting, and do not cut through the accelerator target but heat it, a process that the target can survive merely by rotating!

Lasers also have problems with rotating objects. The US Army's battlefield laser has a lot of trouble shooting down supersonic, rotating artillery.

ClaysGhost · Post by **ClaysGhost** » 2003-01-22 08:34am

His Divine Shadow wrote: Where can I buy these lasers! How big are they? Will they fit in my hand?

You should be more worried about cost than size. There are a few companies that do laser diodes in the 2 - 5kW range nowadays, but they are not ideal for cutting because of the large spot size and rectangular profile. CO2 lasers can be had cabinet sized.

aerius · Post by **aerius** » 2003-01-22 08:45am

That PW laser is absolutely useless! It only uses 680J. This means that the duration of the beam is only 0.000000000000000068 seconds! This absolutely useless for any military appilication. Get over the damn PW laser, its not that great.

Can you not fucking read? Let me hammer this point through your head again. I put the link to the Petawatt laser so you can see the effects that a high power laser will have if we get around to building one that can fire longer pulses or operate in continuous beam mode. The point being a laser will act a lot like a particle beam at PW range power levels. I never claimed the Petawatt laser was an almighty weapon.

Lasers also have problems with rotating objects. The US Army's battlefield laser has a lot of trouble shooting down supersonic, rotating artillery.

That's a targeting issue dumbass, it ain't exactly easy to hit a computer keyboard sized target from a few miles away when it's moving at supersonic speeds. The spin of the shell has nothing to do with it and the fact remains that they CAN shoot the damn shell down. Try lighting up golf balls at a driving range with a laser pointer from say 500' away. Can't do it can you? Trying to hit an artillery shell is far harder than that.

aerius · Post by **aerius** » 2003-01-22 08:45am

That PW laser is absolutely useless! It only uses 680J. This means that the duration of the beam is only 0.000000000000000068 seconds! This absolutely useless for any military appilication. Get over the damn PW laser, its not that great.

Can you not fucking read? Let me hammer this point through your head again. I put the link to the Petawatt laser so you can see the effects that a high power laser will have if we get around to building one that can fire longer pulses or operate in continuous beam mode. The point being a laser will act a lot like a particle beam at PW range power levels. I never claimed the Petawatt laser was an almighty weapon.

Lasers also have problems with rotating objects. The US Army's battlefield laser has a lot of trouble shooting down supersonic, rotating artillery.

That's a targeting issue dumbass, it ain't exactly easy to hit a computer keyboard sized target from a few miles away when it's moving at supersonic speeds. The spin of the shell has nothing to do with it and the fact remains that they CAN shoot the damn shell down. Try lighting up golf balls at a driving range with a laser pointer from say 500' away. Can't do it can you? Trying to hit an artillery shell is far harder than that.

ClaysGhost · Post by **ClaysGhost** » 2003-01-22 08:59am

Arrow Mk84 wrote:
2. "I said a 680J 1PW laser cannot" ... "to cut through sheet metal ... you need many kW of power". As I understand it, PW > kW, by a factor of 10^12. 2kW is sufficient to give stainless steel a hard time. 2kW is not a lot of power.
That PW laser is absolutely useless! It only uses 680J. This means that the duration of the beam is only 0.000000000000000068 seconds! This absolutely useless for any military appilication. Get over the damn PW laser, its not that great.

The PW laser was been mentioned in the message I replied to, and was self-contradictory as I was pointing out. If people continue to talk about the PW laser as if it's the only laser in existence and as if it having a low energy output means that all lasers have the same problem, then I will continue to reply to them and I will continue to talk about it. You want to hear a different tune, then let's talk about the lasers that are designed for military applications, and the lasers that are in use in industry, because so far they are being ignored and it's beginning to annoy me. There is no working practical NPB weapon in existence today. There are practical laser weapons. PBs have horrible efficiency problems and long recharge times (how long do you think it takes to cycle up a bunch of protons to relativistic speeds?), both of which are also being ignored.

Particle accelerators are not used for high-speed industrial metal cutting, and do not cut through the accelerator target but heat it, a process that the target can survive merely by rotating!
Lasers also have problems with rotating objects. The US Army's battlefield laser has a lot of trouble shooting down supersonic, rotating artillery.

Nevertheless, it has been done, and with a device a fraction of the size and energy consumption of NPBs mentioned in this thread (although I doubt anyone could argue the case for a battlefield NPB, given the poor propagation of the beam in atmosphere).

Arrow · Post by **Arrow** » 2003-01-22 09:23am

aerius wrote:
That PW laser is absolutely useless! It only uses 680J. This means that the duration of the beam is only 0.000000000000000068 seconds! This absolutely useless for any military appilication. Get over the damn PW laser, its not that great.
Can you not fucking read? Let me hammer this point through your head again. I put the link to the Petawatt laser so you can see the effects that a high power laser will have if we get around to building one that can fire longer pulses or operate in continuous beam mode. The point being a laser will act a lot like a particle beam at PW range power levels. I never claimed the Petawatt laser was an almighty weapon.

Lasers also have problems with rotating objects. The US Army's battlefield laser has a lot of trouble shooting down supersonic, rotating artillery.
That's a targeting issue dumbass, it ain't exactly easy to hit a computer keyboard sized target from a few miles away when it's moving at supersonic speeds. The spin of the shell has nothing to do with it and the fact remains that they CAN shoot the damn shell down. Try lighting up golf balls at a driving range with a laser pointer from say 500' away. Can't do it can you? Trying to hit an artillery shell is far harder than that.

First point, those affects are much easier to achieve with a PB. Thats what particle accelerators do day-in-day-out. To build a laser in the PW range with a substained output of several seconds is extremely impractical, if not impossible. For destruction on that scale, a PB is a far better weapon.

Second point, targeting wasn't the problem, so watch who you're calling a dumbass. The rotation was. The laser was blasting similar sized targets at similar velocities with ease. I was pointing out that rotation is a problem for both lasers and NPBs. And current particle accelerators are for research only. Lets see what several hundred thousand particles traveling at near c do when they impact the target the same time.

ClaysGhost · Post by **ClaysGhost** » 2003-01-22 10:16am

Arrow Mk84 wrote: First point, those affects are much easier to achieve with a PB. Thats what particle accelerators do day-in-day-out. To build a laser in the PW range with a substained output of several seconds is extremely impractical, if not impossible. For destruction on that scale, a PB is a far better weapon.

The biggest NPBs do not operate at all at those power levels, and hence not on that scale. They operate at megawatt levels. Lasers can operate on megawatt levels in continous mode, and some of them are owned by the military. They are rather smaller than NPBs of similar output in operation today. And the efficiency probably isn't as poor as 1%, unlike those same NPBs. Petawatt operation is completely unnecessary. The PW laser is interesting from a materials science point of view, not a military point of view, and the effect of a laser is very different from the effect of a particle beam which is why materials science teams use both large lasers and large particle beams. There is nothing about particle-beam effects that make them, and only them, uniquely effective as space weapons.

Second point, targeting wasn't the problem, so watch who you're calling a dumbass. The rotation was. The laser was blasting similar sized targets at similar velocities with ease.

An artillery shell is smaller than a rocket, cooler and has a thicker skin. And the shell was destroyed. They're apparently most worried about destroying multiple shells, which is mainly a targetting issue.

I was pointing out that rotation is a problem for both lasers and NPBs. And current particle accelerators are for research only. Lets see what several hundred thousand particles traveling at near c do when they impact the target the same time.

Typical bunches in research accelerators exceed 10^10 particles, far more than 10^5. Let's look at 200,000 particles travelling at 99.9999% of c. Each particle will have a relativistic energy of 660GeV (this would be a big accelerator), so a bunch of 200,000 will carry a total energy of 132PeV. Convert it to popular units. 132PeV = the princely sum of 0.02 Joules. I don't think that would boil much water.

aerius · Post by **aerius** » 2003-01-22 10:20am

Arrow Mk84 wrote:First point, those affects are much easier to achieve with a PB. Thats what particle accelerators do day-in-day-out. To build a laser in the PW range with a substained output of several seconds is extremely impractical, if not impossible. For destruction on that scale, a PB is a far better weapon.

And current particle accelerators are for research only. Lets see what several hundred thousand particles traveling at near c do when they impact the target the same time.

Let me do some math for you so you see how wussy your PB is. These figures are for SLAC which is the most powerful linear accelerator on earth.

By the way, I decided to work out how much energy a linear accelerator uses and the energy of the final beam. Using the SLAC (Stanford Linear Accelerator & Collider) which can be referenced on the web, it uses about 30-40MW of power. This is used to accelerate bunches of about 10^10 electrons to near light speed, and only a few bunches can be accelerated at a time. Let's be generous and assume a bunch is accelerated to 99.99999% of lightspeed. That gives a relativistic energy of just over 100J. From the info I've found so far, they can accelerate about 120 bunches/second, giving an average final energy of 12kJ/s, or 12kW for the particle beam Remember, we have 20kW lasers already.

Factor pulse time into it and you get an instantaneous power of around 30GW tops, which is still a lot less than the Petawatt laser for instance, and you should also note that the total energy per pulse is about 7 times lower for the particle beam.

You're beginning to sound like a trekkie fanboy who can't accept the fact that Trek weapons are pityfully weak compared to Star Wars weapons. In this case you're making up imagined powers and effects because you can't accept that particle beams are still fucking worthless as weapons.

Arrow · Post by **Arrow** » 2003-01-22 10:23am

Ouch. Looks like lasers are better after all.

I do have another question. I know different frequencies effect materials differently, so what would a microwave laser be used for? Or an IR, or UV, or X-Ray (I already know that Gamma is a great way to kill organics but won't do much to metal). Also, type of power levels would be involved in each?

Arrow · Post by **Arrow** » 2003-01-22 10:25am

You know something aerius? You're an idiot. ClaysGhost manage to explain the whole thing without acting like a dick, and I found his argument very convincing. All you've done is piss me off, which is the WRONG way to get a point across.

Admiral Valdemar · Post by **Admiral Valdemar** » 2003-01-22 10:32am

Also, what frequency do you need for the light emitted to be reflected. What are the ranges specifically for using mirrors, X-rays and gamma can't be reflected by mirrors or EM fields I know.

aerius · Post by **aerius** » 2003-01-22 10:37am

Arrow Mk84 wrote:You know something aerius? You're an idiot. ClaysGhost manage to explain the whole thing without acting like a dick, and I found his argument very convincing. All you've done is piss me off, which is the WRONG way to get a point across.

Tough shit, I have little patience with people who make retarded claims and refuse to listen to reason. I was nice enough at first, but when you refused to listen to reason and started pulling shit out of you ass I saw no need to be "nice". Deal with it, I don't give a flying fuck about your feelings.

Arrow · Post by **Arrow** » 2003-01-22 10:54am

Do yourself a favor and study Clay's style. Pissing people off only entrenches them. Fuck it, your not listining anyway.

ClaysGhost · Post by **ClaysGhost** » 2003-01-22 11:40am

Arrow Mk84 wrote:Ouch. Looks like lasers are better after all.

I do have another question. I know different frequencies effect materials differently, so what would a microwave laser be used for? Or an IR, or UV, or X-Ray (I already know that Gamma is a great way to kill organics but won't do much to metal). Also, type of power levels would be involved in each?

Microwave lasers are popular frequency standards in radio observatories (since they can operate at nice reference frequencies). I don't know of any weapon applications for them, although I guess they're capable of heating objects. Probably their most significant ability would be to interfere with electronic devices - most people have probably put a mobile phone near a computer with speakers turned on at some point; you can hear the phone talking to the base station occasionally. Although military equipment would likely be hardened against interference, reducing effectiveness of a microwave laser. Radio technology has been around for years and is well understood, so the possible power output could be quite high, but the masers available today aren't really designed with weapons use in mind, so practical examples are thin on the ground. I should think that significant power outputs would not be required to cause interference with unhardened electronics.

IR is currently the frequency band of choice for weapons applications, and for many other applications too. Partly this is due to the large number of powerful types of laser that work in IR. Targets tend to absorb IR well, and IR is scattered less by atmosphere than higher frequencies. Available powers range from mW communication laser diodes through kW industrial machines (and some weapons) to MW military devices.

UV is troublesome because UV photons have enough energy to ionise air. This can cause problems, but it does make for some interesting applications; there was a mad guy running around recently who wanted to use it to create a stun-gun; the idea was to create two ionised, conducting channels of air to an individual and then pass a disabling electrical current through the circuit so formed. I have no idea what size this device was supposed to be; I think UV is one of the more sparsely covered wavebands for compact lasers.

X-ray and beyond is really the stuff of dreams at the moment. Nuke-pumped lasers are one (bad) solution, extension of the free-electron laser the other (although Connor McLeod was right to wonder about the efficiency of FELs earlier in the thread - quite low compared to other laser types). There are interesting hints that you can use very high power lasers at optical frequencies to kick-start X-ray lasing, and I think this has been achieved only quite recently (forget which facility). Gamma ray lasers are unlikely to be realised soon, even at research level I'd guess. The effects of weapons based on X-ray and gamma ray radiation are probably quite wide-ranging. Atoms are easily ionised by X-rays, and given that gamma-rays are emitted in nuclear decay (which divides them from X-rays) you might possibly render radioactive affected sections of hull. However, these frequencies are very penetrating - internal electronics and crew would be more vulnerable than the hull. I have no idea how much power you could apply at these frequencies.

Admiral Valdemar wrote: Also, what frequency do you need for the light emitted to be reflected. What are the ranges specifically for using mirrors, X-rays and gamma can't be reflected by mirrors or EM fields I know.

Microwaves can be reflected by metal surfaces, or other (good) conductors of electricity. It need not be a solid metal surface; as long as gaps in it are significantly smaller than the wavelength of the radiation, you can use chickenwire. Microwave reflectors can be made very exotic to gain useful optical properties.

IR can be reflected by metals, with 95% efficiency attainable. High energy laser-level optics cannot afford such low efficiency (!) since the optical elements are at risk from the laser beam, so optical components can use tricks like reflection from multi-layered thin films to achieve very high efficiencies indeed.

I'm not sure what mirror materials there are at UV frequencies.

X-rays can be reflected, but it's not really useful reflection. You have to arrange for the X-rays to hit the mirror at "grazing incidence", i.e. the mirror is almost parallel to the direction of travel of the x-rays. The change in trajectory is only a few degrees, enough for a telescope, but not enough for a defence. Gamma rays cannot be reflected by anything I know of.

Admiral Valdemar · Post by **Admiral Valdemar** » 2003-01-22 11:43am

Thanks late, great Jefferson Clay.