Laser weapons general thoughts

[Lexx]

Some people like to point out that the gamma or xray laser would be useless in atmosphere as the air absorbs gamma and xray radiation fairly quickly. In fact this was mentioned in gurps space and high tech.

Well, there is an explanation for how such weapons could be used, with great effect, in atmosphere, despie the fact that air would drastically limit their range in a 'realistic' setting.

I claim that when fired in atmosphere, the gamma/xray lasers actually fire a double pulse, the first pulse being IR. The IR laser pulse heats, expands and thus displaces most of the air along the path of the beam for a nanosecond, thereby allowing the main beam, the gamma/xray laser pulse, to travel thru a 'tunnel' of very low pressure air and not be absorbed by atmosphere as it might otherwise be.


Also, as a side effect of this, the very low pressure air in the 'tunnel' made by the IR laser is in effect a near vaccum, and what happens when you pass high energy along near, but not complete vacuum?

Same thing that happens in a neon light, or in a comet's tail: The gas glows.

So, when a gamma/xray laser is fired in atmosphere in my gurps traveller games, it does have normal range and makes a very pretty streak of secondary light in the air, along with a loud "KRAK!" sound.

In my game, you can tell a Gamma ray laser from an xray laser in atmosphere because the gamme ray laser produced a bluewhite light along the beam, the xray laser produces a violet white streak.


Just something on the subject of laser weapons I opted to share with you.

 

[Lexx]

Some people like to point out that the gamma or xray laser would be useless in atmosphere as the air absorbs gamma and xray radiation fairly quickly. In fact this was mentioned in gurps space and high tech.

Well, there is an explanation for how such weapons could be used, with great effect, in atmosphere, despie the fact that air would drastically limit their range in a 'realistic' setting.

I claim that when fired in atmosphere, the gamma/xray lasers actually fire a double pulse, the first pulse being IR. The IR laser pulse heats, expands and thus displaces most of the air along the path of the beam for a nanosecond, thereby allowing the main beam, the gamma/xray laser pulse, to travel thru a 'tunnel' of very low pressure air and not be absorbed by atmosphere as it might otherwise be.


Also, as a side effect of this, the very low pressure air in the 'tunnel' made by the IR laser is in effect a near vaccum, and what happens when you pass high energy along near, but not complete vacuum?

Same thing that happens in a neon light, or in a comet's tail: The gas glows.

So, when a gamma/xray laser is fired in atmosphere in my gurps traveller games, it does have normal range and makes a very pretty streak of secondary light in the air, along with a loud "KRAK!" sound.

In my game, you can tell a Gamma ray laser from an xray laser in atmosphere because the gamme ray laser produced a bluewhite light along the beam, the xray laser produces a violet white streak.


Just something on the subject of laser weapons I opted to share with you.

 

[mike wightman]

Originally posted by Lexx:
Some people like to point out that the gamma or xray laser would be useless in atmosphere as the air absorbs gamma and xray radiation fairly quickly. In fact this was mentioned in gurps space and high tech.

That's funny, 'cos in GURPS Ultra Tech the x-ray and gamma-ray laser weapons are not affected by the atmosphere, smoke, reflec armour, normal armour is halved for x-ray lasers and divided by five for grasers. The same effects are listed in GT:Starships fot Traveller.

I like your description of how lasers work in YTU by the way

 

[mike wightman]

Originally posted by Lexx:
Some people like to point out that the gamma or xray laser would be useless in atmosphere as the air absorbs gamma and xray radiation fairly quickly. In fact this was mentioned in gurps space and high tech.

That's funny, 'cos in GURPS Ultra Tech the x-ray and gamma-ray laser weapons are not affected by the atmosphere, smoke, reflec armour, normal armour is halved for x-ray lasers and divided by five for grasers. The same effects are listed in GT:Starships fot Traveller.

I like your description of how lasers work in YTU by the way

 

[Lexx]

Actually in ultratech or space, I don't remember which, it said that realistically gamma and xray lasers would have limited range due to the atmosphere, let me look it up.....

Ok, on page 81 of gurps space, 3e revised, it says that xray lasers would be rapidly abosrbed by atmosphere.

 

[Lexx]

Actually in ultratech or space, I don't remember which, it said that realistically gamma and xray lasers would have limited range due to the atmosphere, let me look it up.....

Ok, on page 81 of gurps space, 3e revised, it says that xray lasers would be rapidly abosrbed by atmosphere.

 

[Lexx]

Also gurps space says on page 80 that "realsitically, gamma and xray lasers should not be able to penetrate more than a foot or two of atmosphere. Most SF settings ignore htis."

 

[Lexx]

Also gurps space says on page 80 that "realsitically, gamma and xray lasers should not be able to penetrate more than a foot or two of atmosphere. Most SF settings ignore htis."

 

[mike wightman]

Then how come gamma rays can penetrate a few feet of concrete in the real world? No need to worry about nuclear bombs anymore, the air will protect us
And there's ususally a foot of air between a hospital x-ray machine and the patient.
I think the GURPs Space author has got it wrong.Here's a link , there are quite a few more if you google gamma ray penetration.

 

[mike wightman]

Then how come gamma rays can penetrate a few feet of concrete in the real world? No need to worry about nuclear bombs anymore, the air will protect us
And there's ususally a foot of air between a hospital x-ray machine and the patient.
I think the GURPs Space author has got it wrong.Here's a link , there are quite a few more if you google gamma ray penetration.

 

[Lexx]

Hey, I was going on what the author of gurps space said, and he seemed to be very knowledgable on most matters.

Also, a nuclear blast releases a lot of hard radiation often as neutrons.

 

[Lexx]

Hey, I was going on what the author of gurps space said, and he seemed to be very knowledgable on most matters.

Also, a nuclear blast releases a lot of hard radiation often as neutrons.

 

[Lexx]

AHA! Vindication! Go to this link:

http://www.sew-lexicon.com/gloss_g.htm#GAMMA-RAY%20LASER

read what is says about gamma ray lasers suffering atmospheric attentuation and being suitable for vacuum only.

 

[Lexx]

AHA! Vindication! Go to this link:

http://www.sew-lexicon.com/gloss_g.htm#GAMMA-RAY%20LASER

read what is says about gamma ray lasers suffering atmospheric attentuation and being suitable for vacuum only.

 

[Lexx]

Here it is, for those of you not wishing to search the web page:

GAMMA-RAY LASER (GRASER) - A DIRECTED ENERGY WEAPON (DEW) under DoD's WEAPONS SYSTEMS TECHNOLOGIES (WST). The projection of coherent electromagnetic (EM) energy to a distant target at the speed of light. [www.dtic.mil] Also called Gamma X-ray laser. NOTES: (1) Grasers can be small-size devices. (2) GRASERs penetrate deeply into targets and can produce a range of lethality from SOFT KILL to HARD KILL. (3) GRASERs are being considered ( circa 1999 ) for space appkication against missiles and satellites. (4) Propagation through the atmosphere is attenuated, but a GRASER could attack targets from space to as far down as 40 km above the ground. (5) Countermeasures against GRASERs are difficult because of the deep penetration of its beam. See also ANTIMATTER PARTICLE BEAM (APB), CHARGED PARTICLE BEAM (CPB), HIGH POWER MICROWAVE/RADIO FREQUENCY (HPM/RF), KINETIC ENERGY WEAPON (KEW) and NEUTRAL PARTICLE BEAM (NPB).

It says an orbital graser can operate against targets 40km above the ground. This means that at 25 or so miles up the air is thick enough to degrade them, and at 25 miles it's mighty damn thin air. At sea level.....

 

[Lexx]

Here it is, for those of you not wishing to search the web page:

GAMMA-RAY LASER (GRASER) - A DIRECTED ENERGY WEAPON (DEW) under DoD's WEAPONS SYSTEMS TECHNOLOGIES (WST). The projection of coherent electromagnetic (EM) energy to a distant target at the speed of light. [www.dtic.mil] Also called Gamma X-ray laser. NOTES: (1) Grasers can be small-size devices. (2) GRASERs penetrate deeply into targets and can produce a range of lethality from SOFT KILL to HARD KILL. (3) GRASERs are being considered ( circa 1999 ) for space appkication against missiles and satellites. (4) Propagation through the atmosphere is attenuated, but a GRASER could attack targets from space to as far down as 40 km above the ground. (5) Countermeasures against GRASERs are difficult because of the deep penetration of its beam. See also ANTIMATTER PARTICLE BEAM (APB), CHARGED PARTICLE BEAM (CPB), HIGH POWER MICROWAVE/RADIO FREQUENCY (HPM/RF), KINETIC ENERGY WEAPON (KEW) and NEUTRAL PARTICLE BEAM (NPB).

It says an orbital graser can operate against targets 40km above the ground. This means that at 25 or so miles up the air is thick enough to degrade them, and at 25 miles it's mighty damn thin air. At sea level.....

 

[mike wightman]

Originally posted by Lexx:
Hey, I was going on what the author of gurps space said, and he seemed to be very knowledgable on most matters.

Sorry, I'm not having a go at you Lexx.
I have spent most of this morning researching x-ray and gamma ray lasers and I can't find anything to suggest either would be limited to a few feet of air.
As I said earlier, I think the GURPs author got it wrong.

Also, a nuclear blast releases a lot of hard radiation often as neutrons.

True, the most penetrating types of which are the gamma ray photons and the neutrons. Alpha radiation is absorbed by a few cm of air, beta by a few metres, gamma by several hundred metres, and neutrons by a similar amount.
Here's an interesting article on the effects of a nuclear detonation

 

[mike wightman]

Originally posted by Lexx:
Hey, I was going on what the author of gurps space said, and he seemed to be very knowledgable on most matters.

Sorry, I'm not having a go at you Lexx.
I have spent most of this morning researching x-ray and gamma ray lasers and I can't find anything to suggest either would be limited to a few feet of air.
As I said earlier, I think the GURPs author got it wrong.

Also, a nuclear blast releases a lot of hard radiation often as neutrons.

True, the most penetrating types of which are the gamma ray photons and the neutrons. Alpha radiation is absorbed by a few cm of air, beta by a few metres, gamma by several hundred metres, and neutrons by a similar amount.
Here's an interesting article on the effects of a nuclear detonation

 

[mike wightman]

This discussion with Lexx has got me wondering about the range of other laser frequencies in air.

 

[mike wightman]

This discussion with Lexx has got me wondering about the range of other laser frequencies in air.