B Radiation shielding and redirecting

[sillls]

TL;DR Summary

To redirect or shield against radiation.

Hi, I am looking for the best way to either shield or redirect radiation, particularly Gamma radiation away from vehicles in space with the minimal amount mass. The last thing we need is a few feet of lead. I am hoping to find other options.

I would love to redirect radiation away from a spacecraft . Maybe with a static shield?
Maybe find an atomic structure that could bend radiation around objects the way people found to move light waves around. https://www.bing.com/videos/search?...D2EB5D942E9E783213D5D2EB5D942E9E783&FORM=VIRE
https://today.duke.edu/2006/10/cloakdemo.htmlhttps://www.physicsforums.com/threads/reaching-for-the-stars.976542/
As I understand it, light is a wavelength that can be bent around objects, rendering them invisible.
If we can do that with light then why not Gamma radiation?

Any ideas?

 

[anorlunda]

Are you writing a SciFi story?

 

[phinds]

There must be away to redirect radiation away from a spacecraft .

Whether there is or not, what evidence do you have that there MUST be ? Just because you want something to be so does not make it so.

 

[sillls]

Whether there is or not, what evidence do you have that there MUST be ? Just because you want something to be so does not make it so.

I understand what your trying to say but I am not going to settle for that.

As for evidence. I did post a link about light bending in my post. If we can bend light waves around objects then we should be able to bend other wave lengths of energy. Also this:
I am new to this forums, thank God there is a website devoted to things like this. About me: I am a guy living in VA who is very interested in working on projects that will take me into space. I am hoping to join SpaceX or another company like it and work in space. I have been interested in this ever since I can remember. I went to collage but got out to be apart of the Air National Guard but had to leave. Now I am trying to go back into avionics in the hopes that this will help me get to were I want to go. If you have any suggestions or any job opportunity's that could help me reach my goal, please let me know. Thanks. Sillls

Source:

https://today.duke.edu/2006/10/cloakdemo.html https://www.physicsforums.com/threads/reaching-for-the-stars.976542/

There must be a way that we can protect people from radiation.

 

[phinds]

I understand what your trying to say but I am not going to settle for that.

As for evidence. I did post a link about light bending in my post. If we can bend light waves around objects then we should be able to bend other wave lengths of energy.

There must be a way that we can protect people from radiation.

"Bending light" to ANY significant degree require the mass of something with the mass of a planet (a star would be more likely), so I think you are using a useless analogy in your reasoning.

 

[sillls]

Then check out these two links from Duke University.

I also edited my first post to have all three links there.


https://today.duke.edu/2006/10/cloakdemo.html

 

[sillls]

Are you writing a SciFi story?

Nope.

 

[phinds]

Then check out these two links from Duke University.

Sure, you can make these special materials that reshape the microwaves by changing the refractive index of the material in interesting ways, but that does NOT mean that the waves are going around the object, they are still going through it. You keep bringing up straw-man examples that do not answer my question.

@sillls I am not trying to give you a hard time on this but what you are looking for has never been done on the scale you are talking about and I'm doubtful that it can be done (but certainly could be wrong about that) and I am simply wondering why you think there HAS to be a way to do it. I still think it's just wishful thinking on your part and am wondering if you can point to any accepted theory that would support your belief that it can be done on the scale you envision (protecting a spacecraft with some kind of "field" rather than water or lead shielding.)

 

[sillls]

Sure, you can make these special materials that reshape the microwaves by changing the refractive index of the material in interesting ways, but that does NOT mean that the waves are going around the object, they are still going through it. You keep bringing up straw-man examples that do not answer my question.

I just showed you a video of microwaves moving around an object.
Perhaps it's because it was shown in a two dimensional view. The microwaves are moving around (including above it). But because it's shown in a two dimensional view it appears that the microwaves are still moving through it.
It's like holding water going around a marble.

 

[phinds]

I just showed you a video of microwaves moving around an object.
Perhaps it's because it was shown in a two dimensional view. The microwaves are moving around (including above it). But because it's shown in a two dimensional view it appears that the microwaves are still moving through it.
It's like holding water going around a marble.

Hm ... perhaps I misinterpreted the video but he specifically talks about the refractive index which would be completely irrelevant if things were going around instead of through.

 

[sillls]

Sure, you can make these special materials that reshape the microwaves by changing the refractive index of the material in interesting ways, but that does NOT mean that the waves are going around the object, they are still going through it. You keep bringing up straw-man examples that do not answer my question.

@sillls I am not trying to give you a hard time on this but what you are looking for has never been done on the scale you are talking about and I'm doubtful that it can be done (but certainly could be wrong about that) and I am simply wondering why you think there HAS to be a way to do it. I still think it's just wishful thinking on your part and am wondering if you can point to any accepted theory that would support your belief that it can be done on the scale you envision (protecting a spacecraft with some kind of "field" rather than water or lead shielding.)

Thanks.
Well I could be wrong. When I say has what I am trying to say is I would really like to find a way to make that happen. I will go ahead and edit my original post.

When I saw the videos, I thought that there might be a way to bend Gamma rays around an object. But again, I could be wrong. I was trying to see if it was possible and if this was being tested.

 

[phinds]

... what I am trying to say is I would really like to find a way to make that happen.

Well,good. That makes sense and it would be a great boon to mankind of you (or anyone) could find a way to do it since it is a significant impediment to long-term space travel, and colonization of, say Mars, as well.

 

[marcusl]

The “cloaking device” works by tailoring artificial dielectrics to produce a carefully controlled negative refractive index material. It generated huge excitement a decade ago or so until it was realized that it works only at a single frequency—its bandwidth is so narrow as to be useless.

You can’t engineer these materials for particles, xrays or gamma rays, however, so the idea is doubly DOA. Look somewhere else for a solution.

Also I advise you to research and understand what you are reading before making off-base claims and then arguing with the learned folk here.

 

[sophiecentaur]

The “cloaking device” works by tailoring artificial dielectrics to produce a carefully controlled negative refractive index material. It generated huge excitement a decade ago or so until it was realized that it works only at a single frequency—its bandwidth is so narrow as to be useless.

There will be limits to maximum frequency of operation but it is quite possible to reflect (deflect) X rays using very oblique incidence on a metal surface (they will be absorbed or pass through at steep incidence. This is the principle behind Xray telescopes. It may be worth a search on these telescopes. The advantage would be low mass (compared with lead) but the range of angles could be small.

 

[camondascia84]

I am not sure if this is what you are looking for. There is a type of battery that has been in development for a long time that uses radiation to generate electricity. (like a rolled up solar panel with semi permanent light between the layers...) they have been trying to find a use for radioactive waste and if they can figure out a way to make a surface that absorbs radiation and turns it into power, then i wonder if the same general idea could not be applied to the surface or under surface of a spaceship to generate power instead or shielding against it. the tech is called "betavoltaics" or at least that is a place to start.

quote from my room mate... "we be space pirates. if the universe gives us radiation and debris, we are surely not going to be giving it back" take any resource you can out there.

 

[davenn]

There is a type of battery that has been in development for a long time that uses radiation to generate electricity. (like a rolled up solar panel with semi permanent light between the layers...)

have you got some links for that please ?
never heard of it

 

[mfb]

I am not sure if this is what you are looking for. There is a type of battery that has been in development for a long time that uses radiation to generate electricity. (like a rolled up solar panel with semi permanent light between the layers...) they have been trying to find a use for radioactive waste and if they can figure out a way to make a surface that absorbs radiation and turns it into power, then i wonder if the same general idea could not be applied to the surface or under surface of a spaceship to generate power instead or shielding against it. the tech is called "betavoltaics" or at least that is a place to start.

That doesn't help you with shielding, and the power you would get from ionizing radiation in space is completely negligible.
Absorbing ~1 J/kg of ionizing radiation is likely to kill you if some of it is from atomic nuclei. That's the energy density your body uses every second just for staying alive.

 

[sophiecentaur]

if the same general idea could not be applied to the surface or under surface of a spaceship to generate power instead or shielding against it. the tech is called "betavoltaics" or at least that is a place to start.

There are two entirely different issues here. There is the need for protection and there is a requirement for power. Unfortunately the large amount of Power needed for the craft would imply a density of radiation that would be worse than a little bit lethal. You will notice that the tech is called Betavoltaics. The Beta Particles (fast electrons) that are used are essentially local products from radioactive substances which can be used relatively safely inside a container.

 

[gleem]

The only way to protect astronauts is to assure that gamma radiation dissipates all its energy in something before it reaches the crew. Lots of stuff preferably high Z. As far as charged particles are concerned they can theoretically be deflected by a large electric field but this is not practical because the energies of these particles are typically too high to be affected much by the field one could typically generate and deploy.

 

[sophiecentaur]

Still no views about the glancing reflection idea? It is known technology at modest energies.

 

[marcusl]

How does one protect a ship from gamma rays incident over 4*pi steradians?

 

[sophiecentaur]

How does one protect a ship from gamma rays incident over 4*pi steradians?

That is a fair question but some directions (eg galactic plane) are worse than others.
In any case, the ‘optics’ of this are non standard. You can have layers which will not affect each other. The structure would need to be big, of course because you can only achieve small deflection angles. Also, you’d not be able to see out in many directions but the screens could be mobile. It would be more like a long period in a submarine than a picturesque ride in the ISS.

 

[camondascia84]

"That doesn't help you with shielding"

Am i missing something? absorbing energy means it is not there to continue into the ship. thus absorbing the radiation as energy would effectively "redirect" it. conservation of energy and all... maybe the concept is not a solution in itself but it might lessen what shielding is needed.

"power you would get from ionizing radiation in space is completely negligible"

the power we got from solar panels was negligible at first too. advancements in tech are not only continual but often produce results we were not expecting. i think that this concept is worth further study and experimentation.

 

[camondascia84]

Here is a link about betavoltaic devices. There is a list of references at the bottom that you might want to check out to fill in a few gaps. http://large.stanford.edu/courses/2013/ph241/harrison2/

 

[sophiecentaur]

Am i missing something?

Yes. You are missing the numbers and some basics of high energy Physics'
Firstly, there is just not enough Energy available (even with 100% conversion efficiency) to make it worth while. Wiki suggests "upper limits as low as 3.4 × 10−6 erg·cm−2 on the flux of 1 GeV – 1 TeVcosmic rays from gamma-ray bursts" and there are 10⁷ergs per Joule, iirc ( they are tiny).

Secondly, these little devils will damage us in very small quantities. There is no material that is low enough density to clad a ship with, that will absorb enough of the radiation to achieve safe levels.
The only solution would have to be to deflect the radiation or find a way to put up with it. Cockroaches and a few others seem to manage it but I cannot see humans doing it.

Cosmic rays consisting of high energy charged particles are dealt with by the Earth's magnetic field but doing the same thing for a spaceship would consume a lot of power.

 

[camondascia84]

Yes. You are missing the numbers and some basics of high energy Physics'
Firstly, there is just not enough Energy available (even with 100% conversion efficiency) to make it worth while. Wiki suggests "upper limits as low as 3.4 × 10−6 erg·cm−2 on the flux of 1 GeV – 1 TeVcosmic rays from gamma-ray bursts" and there are 10⁷ergs per Joule, iirc ( they are tiny).

Secondly, these little devils will damage us in very small quantities. There is no material that is low enough density to clad a ship with, that will absorb enough of the radiation to achieve safe levels.
The only solution would have to be to deflect the radiation or find a way to put up with it. Cockroaches and a few others seem to manage it but I cannot see humans doing it.

Cosmic rays consisting of high energy charged particles are dealt with by the Earth's magnetic field but doing the same thing for a spaceship would consume a lot of power.

i think the idea of "worth while" is subjective. even if the concept does not generate enough energy to power anything, if it absorbs and redirects any of the harmful energy into electricity, then it would be doing its job... also as for how the Earth does this thing we are talking about. it has thousands and thousands of miles to affect those waves and particles away from us. and it does not so much bend them as gently flare them out and away. i think what i am trying to point out is that if we did it via a field of some kind, the field would have to be enormous, not just powerful... or ridiculously powerful to fit the smaller scale... so yes... "a lot of power"

 

[camondascia84]

something i feel should be pointed out is that any form of protection regardless of what form it takes will need to be either variable or designed for a VERY wide range of wavelength... i am sure there are lots of types of radiation and whatnot that we have yet to detect out there. and every moment has the chance to bring something new. we still don't really know what is out there.

 

[mfb]

"That doesn't help you with shielding"

Am i missing something? absorbing energy means it is not there to continue into the ship. thus absorbing the radiation as energy would effectively "redirect" it. conservation of energy and all... maybe the concept is not a solution in itself but it might lessen what shielding is needed.

The absorption is there anyway. The only difference is if you bother to get a few microwatts out of the absorbing material while limiting the range of possible absorbers - making you have to choose a worse absorber - or not.

"power you would get from ionizing radiation in space is completely negligible"

the power we got from solar panels was negligible at first too. advancements in tech are not only continual but often produce results we were not expecting. i think that this concept is worth further study and experimentation.

You can't exceed 100% efficiency, and the power is negligible even at 100% efficiency. The concept is a non-starter.

@sophiecentaur: That also applies to the x-ray deflection idea. The angles are just too shallow and x-rays are absorbed easily by materials.

 

[camondascia84]

The absorption is there anyway. The only difference is if you bother to get a few microwatts out of the absorbing material while limiting the range of possible absorbers - making you have to choose a worse absorber - or not.
You can't exceed 100% efficiency, and the power is negligible even at 100% efficiency. The concept is a non-starter.

@sophiecentaur: That also applies to the x-ray deflection idea. The angles are just too shallow and x-rays are absorbed easily by materials.

the idea was not so much to generate enough power to make it a viable energy source as it was to make shielding more effective. my thought was that maybe by converting a portion of the energy into electricity, you could minimize the energy that carries through as damage.

 

[sophiecentaur]

i think the idea of "worth while" is subjective. even if the concept does not generate enough energy to power anything, if it absorbs and redirects any of the harmful energy into electricity, then it would be doing its job...

But the prime objective would be to attenuate the incident energy. You are suggesting the equivalent of having an electrical generator coupled to the inertial reel of car seat belts to use some of the energy from a car crash to help charge the battery The cost (and payload) involved with the extra 'energy harvesting' system would really be a waste of time when the overwhelming need is for screening. Moreover, weight for weight, the screening would probably be less.

 

[mfb]

the idea was not so much to generate enough power to make it a viable energy source as it was to make shielding more effective. my thought was that maybe by converting a portion of the energy into electricity, you could minimize the energy that carries through as damage.

I know - but it doesn't do that, as I explained. It won't even be neutral. It will make shielding worse because now the shielding can't just be effective with shielding, it must also allow extracting energy that would otherwise become heat.

 

[camondascia84]

But the prime objective would be to attenuate the incident energy. You are suggesting the equivalent of having an electrical generator coupled to the inertial reel of car seat belts to use some of the energy from a car crash to help charge the battery The cost (and payload) involved with the extra 'energy harvesting' system would really be a waste of time when the overwhelming need is for screening. Moreover, weight for weight, the screening would probably be less.

the difference being that seat belt systems are not made of a hundred pounds of lead. and if they WERE, auto companies might think such a system could be worth it if it only weighed a few pounds... I thought the main objective here was to find any way to reduce the need for such drastic shielding even if by only a small amount... or are we only interested if it is a complete and perfect solution? also any argument that only relies on the limitations of modern materials should fall flat on its face. these days science is finding new materials with new properties, all the time.

 

[sophiecentaur]

by only a small amount...

I can't see where you are trying to go with this.
I'm afraid that "a small amount" could be anything. Have you actually calculated how much energy is involved? You do not seem to have taken on board that an energy conversion system will have less shielding effect, per kilo of payload, than a specific screening system. It will be many generations of spaceflight before payload is not a very high priority (the second priority after biological safety.
My example of a seat belt reel was aimed at the present seatbelt design. If there were a large mass that was occasionally brought to a halt then energy harvesting could be worth while. We already use regen braking, so it is worth it but that's because the numbers are appropriate - it's called Engineering.
There is nothing in principle against getting electrical power from radiation but when the quantity is so small and the need for screening so great that there is no significance in your "small amount".

 

[camondascia84]

I can't see where you are trying to go with this.
I'm afraid that "a small amount" could be anything. Have you actually calculated how much energy is involved? You do not seem to have taken on board that an energy conversion system will have less shielding effect, per kilo of payload, than a specific screening system. It will be many generations of spaceflight before payload is not a very high priority (the second priority after biological safety.
My example of a seat belt reel was aimed at the present seatbelt design. If there were a large mass that was occasionally brought to a halt then energy harvesting could be worth while. We already use regen braking, so it is worth it but that's because the numbers are appropriate - it's called Engineering.
There is nothing in principle against getting electrical power from radiation but when the quantity is so small and the need for screening so great that there is no significance in your "small amount".

sigh... do i have to repeat myself every single time i post? all this was suggested to do is slightly reduce the strain on the actual shielding. it was never suggested as a complete solution nor as more than a different way to absorb energy that would otherwise have to be absorbed by shielding. radiation that is turned into electricity would not turn into heat. even a small increment of damage that the shielding does not have to take should be worth looking into. for all you know this could be implemented with a simple coat of currently unknown paint.
but instead, you would rather decide that what you know is definite. i was under the impression that the thing that makes us scholars is our understanding of what we DO NOT know. for gods sake, Ben Franklin KNEW electricity was a liquid... and because such a learned man said so and had "verifiable evidence" many scientists of the time agreed with him.

 

[phinds]

... all this was suggested to do is slightly reduce the strain on the actual shielding.

And you keep ignoring repeated statements that it will NOT reduce the strain on the actual shielding unless you increase the total mass involved, which makes it not a good idea.

 

[camondascia84]

And you keep ignoring repeated statements that it will NOT reduce the strain on the actual shielding unless you increase the total mass involved, which makes it not a good idea.

you've tried this have you? isn't that what science is about? testing things before we are absolutely certain of them? we do not know everything about everything. and it is those unknown discoveries that make science so wonderful. because we are still trying to figure out what is out there. we can run test after test. but until you try everything, you cannot be certain. try to keep an open mind. i cannot say it enough, materials science is making new findings all the time.

 

[sophiecentaur]

isn't that what science is about?

You aren't talking Science; you are talking ignorance of Engineering and Technology. What possible sort of system are you actually proposing that would be 'better' than lead / concrete or some other dense substance and which would make good use of the small amount of power that is carried by the cosmic rays? What sort of "strain" are you suggesting that the screening material is subjected to?

You are in the land of 'Wouldn't it be nice if', which has a rich supply of Unobtainium. Pretty much nonsense all round, I'm afraid. To follow PF rules you need to cite some evidence to support your ideas. Do you have a single credible reference to this?

 

[mfb]

To shield against radiation you need some material that converts the ionizing radiation to several low-energy particles. Once you have done this the radiation is not harmful any more.
To extract energy from radiation you need some material that converts the ionizing radiation to several low-energy particles and some additional material to use these low-energy particles. While this additional material can also do the initial conversion it won't be better in it (otherwise you would use it everywhere). Harvesting the energy cannot improve overall shielding because it is a step that happens downstream. In practice it will get worse because you are more limited in the material choice for some elements.

To make it worse: If you don't plan to extract energy you can just use any bulk material, stopping everything in the material. If you plan to extract energy you need to make sure the particles reach your setup. You are more limited in the material choice here as well and you need a more complex geometry. Your shielding will be worse.

 

[DBO]

X-ray optics just happens to be my field and by extension, gamma ray optics. Short answer about redirecting very short wavelength radiation.....Its really hard but not impossible. For most such energies, reflectivities are so low that you effectively just absorb the radiation. You could do it by reflecting at extreme grazing incidence with reflectivity of .999 and use hundreds of reflections, say 200 reflections at .01 degree or 2 degrees deflection. Still.999 to the 200th power is .81 meaning you've absorbed 19% just deflecting 2 degrees. Now try deflecting 180 degrees (around an object) and you get 1.5e-9 meaning you've absorbed all of it.

 

[Nik_2213]

IMHO, DBO's totally called it on the 'shadow angle'. An absorbing or grazing incidence system set out on a long pylon like the ultimate 'selfie stick' some-what shelters you from that one narrow vector.

Which, IIRC, is where those 'classic' inter-planetary rocket designs, their NERVA-ish nuclear engine and hab separated by a v-e-r-y--l-o-n-g trellis spine, got their start. Think '2001' book/movie and the 'Discovery-1'. They were more interested in minimising their neutron shield's mass, but same 'shadow angle' geometry applies...

Now, if you face multiple radiation sources from very predictable directions, I suppose you could have multiple 'selfie-sticks'. Even if you cross-tie those masts for stability, per 'Tall Ships' rigging, it soon gets a bit unwieldy, a tad wibbly. And, surely, there's a break-even point where, instead of multiple minimal shields on flimsy pylons, makes more sense to keep all that mass closer to the hab, mounted such it won't wibble at the least delta-V...

Bad news, you'd probably do better building a near-spherical bunker of asteroidal slag or, if beyond the ice-line, ice. Think 'swimming pool reactor', but inside-out. Extra thickness between you and your reactor, of course, of course. Requisite mass-haul hurts...

IMHO, if you want a 'force field-ish' whatsit that can efficiently 'steer' such high energy photons, it's probably related to the 'confinement system' around your 'Mr. Fusion Home Energy Reactor'. Requiring multiple major theory and tech advances, that's likely to remain hypothetical for a good while...
;-(

 

[DBO]

Unfortunatly, the most x-ray and gamma ray reflective materials are high Z and high density materials such as gold or Tungsten, etc. Because the number of reflections to direct a beam around an object is so high, the total absorption is also very high. You are better of using normal lead absorbers.
This is not a foolish question as I was paid in 1986 t do a study of the use of reflective materials to protect US satellites from a "hypothetical" Soviet nuclear pumped x-ray laser emitting a nominal 1 KeV beam with power density of 10E14 s/cm2 at a distance of 1000 Km. It was a $50,000 6 month program.
Here is my study. Assume a reflectivity of 99% meaning it absorbs 1%. This means it absorbs 10E13 watts/Cm2 of 1 KeV radiation in a time of 50 nanoseconds. Answer: No, no material will withstand that power density in 50 nS
I spent th remaining $49,000 becoming an expert on high heat load x-ray mirrors.

 

[DBO]

OOOps, should have been 10E14 watts/cm2 incident then 10E12 watts/cm2 is absorbed.
BTW, just out of interest, index of refraction for x and gammas is less than 1 and has a major imaginary part corsponding to absorption.

 

[bahamagreen]

To the degree that the exposure problem comprises mechanical damage impairing the functionality of genetic molecules, seeing that the human genome project is way ahead of schedule, and anticipating nanobots, the long term solution may be biological intervention rather than shielding.

The way forward may be to allow an otherwise lethal count of gamma ray passage through the astronauts; then mitigate the damage incurred to the genetic molecules continuously, repaired by the nanobots propagated, stationed, and operating together within every cell nucleus...?

 

[marcusl]

And now we’ve come full circle from one sci-fi fantasy to another.

 

[berkeman]

And now we’ve come full circle from one sci-fi fantasy to another.

Agreed. This is a good time to tie off this thread.