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More information on the topic: https://www.bnl.gov/magnets/st...

How have you been on /. as long as your ID implies and never learned the difference between ionizing and non-ionizing radiation?

Are you just that stupid?

Thanks for the flowers,

https://www.bloomberg.com/news...

"Apple is exploring cutting-edge technologies that would allow iPhones and iPads to be powered from further away than the charging mats used with current smartphone"

To charge a cell phone over the air - receiving a couple of 100 mA by radio waves in a room with your cell - maybe within 20' distance - you'll need either a concentrated beam to which you expose your cell or have the whole room covered with a very strong RF field maybe similar what the exposure to your head is when listening to your phone which transmits about 1 Watt when sending, which affects your brain:

https://www.bnl.gov/newsroom/n...

and potentially creates carcinoms

http://biorxiv.org/content/ear...

- all non-ionizing radiation but affecting cells in bodies exposed to those conditions

Companies are only motivated by maximizing profit not by what is good or bad for people or environment

In this case the "radiation" is the emission of high-energy neutron particles. Neutrons will run into anything *... and when they do, they transfer a ton of their energy into whatever they hit... causing "damage cascades" as atoms get tossed around (Wikipedia has a decent animation here: https://en.wikipedia.org/wiki/... ).

That atom-scale damage adds up after a while... causing material failure... regardless of the type of material.

For instance, inside of a reactor all of the steel holding all of the fuel in place is constantly bombarded... leading to all sorts of effects like radiation induced swelling and embrittlement.

In humans the primary issue is when those neutrons hit DNA / cells and damage them. It actually happens to us all day long from radiation around us... but our bodies can deal with a certain amount. Too much damage though... and your body can't cope any more.

In robots / electronics the issue is much the same. The neutrons run into _everything_ and degrade it. More sensitive pieces (like camera sensors) will degrade rather quickly while larger components (like structural steel) will most likely be fine for long periods of time.

* The probability that a neutron will hit a certain type of atom is called a "cross section" (XS) and is an _extremely_ well studied phenomenon. You can look at some here: https://www.nndc.bnl.gov/sigma... for instance, this is the probability for a neutron running into Hydrogen: https://www.nndc.bnl.gov/sigma...

In this case the "radiation" is the emission of high-energy neutron particles. Neutrons will run into anything *... and when they do, they transfer a ton of their energy into whatever they hit... causing "damage cascades" as atoms get tossed around (Wikipedia has a decent animation here: https://en.wikipedia.org/wiki/... ).

That atom-scale damage adds up after a while... causing material failure... regardless of the type of material.

For instance, inside of a reactor all of the steel holding all of the fuel in place is constantly bombarded... leading to all sorts of effects like radiation induced swelling and embrittlement.

In humans the primary issue is when those neutrons hit DNA / cells and damage them. It actually happens to us all day long from radiation around us... but our bodies can deal with a certain amount. Too much damage though... and your body can't cope any more.

In robots / electronics the issue is much the same. The neutrons run into _everything_ and degrade it. More sensitive pieces (like camera sensors) will degrade rather quickly while larger components (like structural steel) will most likely be fine for long periods of time.

* The probability that a neutron will hit a certain type of atom is called a "cross section" (XS) and is an _extremely_ well studied phenomenon. You can look at some here: https://www.nndc.bnl.gov/sigma... for instance, this is the probability for a neutron running into Hydrogen: https://www.nndc.bnl.gov/sigma...

Indeed, most plans call for varying materials - and not just with respect to the inside/outside, but also with where they are on the spacecraft. Even the passengers' own bodies act as shielding for other other passengers and needs to be taken into account. Modeling radiation and health risks on interplanetary missions is not a simple task!

If anyone wants to get more of a sense of how cross sections of different elements / isotopes can vary with different types and energies of radiation, I strongly recommend the Sigma server. Start off with neutrons (although you can change that in the dropdown on the top right), pick an isotope, then look at the options on the right. You'll see lots of entries of the form (n, X). The first part in the parentheses is what the incoming particle is; the second part is what the heaviest outgoing particles are. (n,gamma) for example means that there are no nucleons that result from the collision, only gamma; this is a simple neutron-capture transmutation. (n, total) means the total of all cross sections; (n, elastic) is elastic scattering (the dominant method of moderation at low energies; follows the same sort of energy/angular momentum distribution as elastic collisions between objects on macroscopic scales); (n, inelastic) is inelastic scattering (an additional loss mechanism at high energies where the particle is absorbed and then re-emitted, with a more complex energy distribution), etc. Click on "plot" for any category and it'll show you the result.

For example, here's the (n,alpha) for 10B, a well known neutron absorber. And indeed, these are very high cross sections compared to, say, the odds of elemental carbon doing anything to get rid of the neutron. But note how vastly higher the cross sections are in the thermal (meV) spectrum than they are in the fast (MeV) spectrum. Even with boron, you're unlikely to capture fast neutrons (MeV range or higher) except with a great thickness of absorber. But if you moderate them down - moderation having a high cross section - then they become easy to capture. Remember when looking at these charts that 1H is also 1/10th the molar mass of 10B.

On the other hand, low-Z (light) materials aren't that great at blocking certain types of radiation - if you want to block EM radiation spectrum, for example, you want high-Z materials (that's why there's the standard "lead apron" for getting an x-ray). But the balance of effects in space turns out to favor the need for low-Z materials.

If the terms above like "cross sections" are unfamiliar... picture a particle of any type of radiation like a baseball pitched randomly toward an area where someone has hung a bunch of spheres. What's the odds that the baseball is going to hit one of them? Well, it depends on the cross section that they present to the ball. While a naive expectation might be that it would just simply be proportional to the size of the atoms, in practice different isotopes vary widely in their different effective cross sections to different particles and different reactions. Still, cross sections are measured in "barns", which is a unit scaled to be roughly the size of typical atomic physical cross sections for comparison purposes. Anyway, you can just read nuclear cross sections as "how likely a reaction is per unit traveled through the target".

Oh, and I forgot to mention one other thing: when picking shielding materials, neutron capture or other transmutation reactions alter the isotope that they hit. Often what they produce will be unstable and will decay - sometimes multiple times - releasing more radiation. So it's also important to look

Indeed, most plans call for varying materials - and not just with respect to the inside/outside, but also with where they are on the spacecraft. Even the passengers' own bodies act as shielding for other other passengers and needs to be taken into account. Modeling radiation and health risks on interplanetary missions is not a simple task!

If anyone wants to get more of a sense of how cross sections of different elements / isotopes can vary with different types and energies of radiation, I strongly recommend the Sigma server. Start off with neutrons (although you can change that in the dropdown on the top right), pick an isotope, then look at the options on the right. You'll see lots of entries of the form (n, X). The first part in the parentheses is what the incoming particle is; the second part is what the heaviest outgoing particles are. (n,gamma) for example means that there are no nucleons that result from the collision, only gamma; this is a simple neutron-capture transmutation. (n, total) means the total of all cross sections; (n, elastic) is elastic scattering (the dominant method of moderation at low energies; follows the same sort of energy/angular momentum distribution as elastic collisions between objects on macroscopic scales); (n, inelastic) is inelastic scattering (an additional loss mechanism at high energies where the particle is absorbed and then re-emitted, with a more complex energy distribution), etc. Click on "plot" for any category and it'll show you the result.

For example, here's the (n,alpha) for 10B, a well known neutron absorber. And indeed, these are very high cross sections compared to, say, the odds of elemental carbon doing anything to get rid of the neutron. But note how vastly higher the cross sections are in the thermal (meV) spectrum than they are in the fast (MeV) spectrum. Even with boron, you're unlikely to capture fast neutrons (MeV range or higher) except with a great thickness of absorber. But if you moderate them down - moderation having a high cross section - then they become easy to capture. Remember when looking at these charts that 1H is also 1/10th the molar mass of 10B.

On the other hand, low-Z (light) materials aren't that great at blocking certain types of radiation - if you want to block EM radiation spectrum, for example, you want high-Z materials (that's why there's the standard "lead apron" for getting an x-ray). But the balance of effects in space turns out to favor the need for low-Z materials.

If the terms above like "cross sections" are unfamiliar... picture a particle of any type of radiation like a baseball pitched randomly toward an area where someone has hung a bunch of spheres. What's the odds that the baseball is going to hit one of them? Well, it depends on the cross section that they present to the ball. While a naive expectation might be that it would just simply be proportional to the size of the atoms, in practice different isotopes vary widely in their different effective cross sections to different particles and different reactions. Still, cross sections are measured in "barns", which is a unit scaled to be roughly the size of typical atomic physical cross sections for comparison purposes. Anyway, you can just read nuclear cross sections as "how likely a reaction is per unit traveled through the target".

Oh, and I forgot to mention one other thing: when picking shielding materials, neutron capture or other transmutation reactions alter the isotope that they hit. Often what they produce will be unstable and will decay - sometimes multiple times - releasing more radiation. So it's also important to look

Indeed, most plans call for varying materials - and not just with respect to the inside/outside, but also with where they are on the spacecraft. Even the passengers' own bodies act as shielding for other other passengers and needs to be taken into account. Modeling radiation and health risks on interplanetary missions is not a simple task!

If anyone wants to get more of a sense of how cross sections of different elements / isotopes can vary with different types and energies of radiation, I strongly recommend the Sigma server. Start off with neutrons (although you can change that in the dropdown on the top right), pick an isotope, then look at the options on the right. You'll see lots of entries of the form (n, X). The first part in the parentheses is what the incoming particle is; the second part is what the heaviest outgoing particles are. (n,gamma) for example means that there are no nucleons that result from the collision, only gamma; this is a simple neutron-capture transmutation. (n, total) means the total of all cross sections; (n, elastic) is elastic scattering (the dominant method of moderation at low energies; follows the same sort of energy/angular momentum distribution as elastic collisions between objects on macroscopic scales); (n, inelastic) is inelastic scattering (an additional loss mechanism at high energies where the particle is absorbed and then re-emitted, with a more complex energy distribution), etc. Click on "plot" for any category and it'll show you the result.

For example, here's the (n,alpha) for 10B, a well known neutron absorber. And indeed, these are very high cross sections compared to, say, the odds of elemental carbon doing anything to get rid of the neutron. But note how vastly higher the cross sections are in the thermal (meV) spectrum than they are in the fast (MeV) spectrum. Even with boron, you're unlikely to capture fast neutrons (MeV range or higher) except with a great thickness of absorber. But if you moderate them down - moderation having a high cross section - then they become easy to capture. Remember when looking at these charts that 1H is also 1/10th the molar mass of 10B.

On the other hand, low-Z (light) materials aren't that great at blocking certain types of radiation - if you want to block EM radiation spectrum, for example, you want high-Z materials (that's why there's the standard "lead apron" for getting an x-ray). But the balance of effects in space turns out to favor the need for low-Z materials.

If the terms above like "cross sections" are unfamiliar... picture a particle of any type of radiation like a baseball pitched randomly toward an area where someone has hung a bunch of spheres. What's the odds that the baseball is going to hit one of them? Well, it depends on the cross section that they present to the ball. While a naive expectation might be that it would just simply be proportional to the size of the atoms, in practice different isotopes vary widely in their different effective cross sections to different particles and different reactions. Still, cross sections are measured in "barns", which is a unit scaled to be roughly the size of typical atomic physical cross sections for comparison purposes. Anyway, you can just read nuclear cross sections as "how likely a reaction is per unit traveled through the target".

Oh, and I forgot to mention one other thing: when picking shielding materials, neutron capture or other transmutation reactions alter the isotope that they hit. Often what they produce will be unstable and will decay - sometimes multiple times - releasing more radiation. So it's also important to look

Indeed, most plans call for varying materials - and not just with respect to the inside/outside, but also with where they are on the spacecraft. Even the passengers' own bodies act as shielding for other other passengers and needs to be taken into account. Modeling radiation and health risks on interplanetary missions is not a simple task!

If anyone wants to get more of a sense of how cross sections of different elements / isotopes can vary with different types and energies of radiation, I strongly recommend the Sigma server. Start off with neutrons (although you can change that in the dropdown on the top right), pick an isotope, then look at the options on the right. You'll see lots of entries of the form (n, X). The first part in the parentheses is what the incoming particle is; the second part is what the heaviest outgoing particles are. (n,gamma) for example means that there are no nucleons that result from the collision, only gamma; this is a simple neutron-capture transmutation. (n, total) means the total of all cross sections; (n, elastic) is elastic scattering (the dominant method of moderation at low energies; follows the same sort of energy/angular momentum distribution as elastic collisions between objects on macroscopic scales); (n, inelastic) is inelastic scattering (an additional loss mechanism at high energies where the particle is absorbed and then re-emitted, with a more complex energy distribution), etc. Click on "plot" for any category and it'll show you the result.

For example, here's the (n,alpha) for 10B, a well known neutron absorber. And indeed, these are very high cross sections compared to, say, the odds of elemental carbon doing anything to get rid of the neutron. But note how vastly higher the cross sections are in the thermal (meV) spectrum than they are in the fast (MeV) spectrum. Even with boron, you're unlikely to capture fast neutrons (MeV range or higher) except with a great thickness of absorber. But if you moderate them down - moderation having a high cross section - then they become easy to capture. Remember when looking at these charts that 1H is also 1/10th the molar mass of 10B.

On the other hand, low-Z (light) materials aren't that great at blocking certain types of radiation - if you want to block EM radiation spectrum, for example, you want high-Z materials (that's why there's the standard "lead apron" for getting an x-ray). But the balance of effects in space turns out to favor the need for low-Z materials.

If the terms above like "cross sections" are unfamiliar... picture a particle of any type of radiation like a baseball pitched randomly toward an area where someone has hung a bunch of spheres. What's the odds that the baseball is going to hit one of them? Well, it depends on the cross section that they present to the ball. While a naive expectation might be that it would just simply be proportional to the size of the atoms, in practice different isotopes vary widely in their different effective cross sections to different particles and different reactions. Still, cross sections are measured in "barns", which is a unit scaled to be roughly the size of typical atomic physical cross sections for comparison purposes. Anyway, you can just read nuclear cross sections as "how likely a reaction is per unit traveled through the target".

Oh, and I forgot to mention one other thing: when picking shielding materials, neutron capture or other transmutation reactions alter the isotope that they hit. Often what they produce will be unstable and will decay - sometimes multiple times - releasing more radiation. So it's also important to look

Fast neutron cross scattering sections in the couple MeV range barely vary over more than the range of 1-10 barns

1-10 barns is, of course, by definition, an order of magnitude. There is a massive difference between 10 barns and 1 barn. Tenfold, to be precise. ;)

More to the point, you can't just combine all cross sections like that. The energy imparted from an elastic collision isn't the same as from an inelastic collsiion, which isn't the same as an (n, gamma), and so forth. Elastic collisions are particularly low energy, particularly the higher Z the target. Taking them out of the equation yields much greater differences between materials in the range of a couple MeV. The upper end of the neutron energies are "somewhat" similar (up to about one order of magnitude), but down below 6 or 7 MeV or so there's quite a few orders of magnitude difference.

Likewise, total cross sections have no bearing on the accumulation of impurities in the material. The particular cross sections are relevant not only in terms of reaction rate, but also what sort of impurities you tend to accumulate and what effect they have on the properties of the material. Which of course varies greatly depending on what exactly they are.

Integration of annealing cycles into blanket design is not brought up enough in some design studies, but is a consideration to help

It's not a side issue, it's a fundamental issue to the design of a material designed for high temperature operation under a high neutron flux.

Blanket design is extremely constrained by tritium breeder ratio to ensure more tritium is produced than used, which squeezes volume allowed to be used by coolant, ... but they have much lower neutron flux to worry about. Gen 4 reactor designs are in the 500-1000 C temperature range, exceeding in some cases what is thought reasonable for fusion blanket design. ... Blanket replacement is considerably more complex than fuel replacement in a fission reactor

Perhaps they've been heading in a different direction since I was last reading on the topic, but I was under the impression that a prime blanket material under consideration was FLiBe. Which operates in a temperature range of 459-1430C, and is its own coolant. That doesn't change what the first wall has to tolerate, but as for the blanket itself, you have no "structural properties" to maintain, and cooling is only limited by the speed that you can cycle it.

The last paper I read on the subject also suggested that for breeding purposes one needs not only beryllium (they were reporting really poor results with high-Z multipliers), but the optimum ratio (to my surprise) worked out to be significantly more beryllium than lithium. So building structural elements out of beryllium serves double purpose, you don't have the excuse of "I need to use steel because it's cheaper" - you need the beryllium either way. It's strong, low density, similar melting point to steel, but retains strength better with heat, and highly thermally conductive. Beryllium swelling from helium accumulation stops at 750C+ as helium release occurs. So pairing a beryllium first wall with a FLiBe-based blanket seems like a very appropriate option.

Please don't get me wrong, I'm not at all disputing the great amount of engineering work left to do. I'm just more optimistic that appropriate solutions will be found. Perhaps I'm just naive in that regard ;)

Fast neutron cross scattering sections in the couple MeV range barely vary over more than the range of 1-10 barns

1-10 barns is, of course, by definition, an order of magnitude. There is a massive difference between 10 barns and 1 barn. Tenfold, to be precise. ;)

More to the point, you can't just combine all cross sections like that. The energy imparted from an elastic collision isn't the same as from an inelastic collsiion, which isn't the same as an (n, gamma), and so forth. Elastic collisions are particularly low energy, particularly the higher Z the target. Taking them out of the equation yields much greater differences between materials in the range of a couple MeV. The upper end of the neutron energies are "somewhat" similar (up to about one order of magnitude), but down below 6 or 7 MeV or so there's quite a few orders of magnitude difference.

Likewise, total cross sections have no bearing on the accumulation of impurities in the material. The particular cross sections are relevant not only in terms of reaction rate, but also what sort of impurities you tend to accumulate and what effect they have on the properties of the material. Which of course varies greatly depending on what exactly they are.

Integration of annealing cycles into blanket design is not brought up enough in some design studies, but is a consideration to help

It's not a side issue, it's a fundamental issue to the design of a material designed for high temperature operation under a high neutron flux.

Blanket design is extremely constrained by tritium breeder ratio to ensure more tritium is produced than used, which squeezes volume allowed to be used by coolant, ... but they have much lower neutron flux to worry about. Gen 4 reactor designs are in the 500-1000 C temperature range, exceeding in some cases what is thought reasonable for fusion blanket design. ... Blanket replacement is considerably more complex than fuel replacement in a fission reactor

Perhaps they've been heading in a different direction since I was last reading on the topic, but I was under the impression that a prime blanket material under consideration was FLiBe. Which operates in a temperature range of 459-1430C, and is its own coolant. That doesn't change what the first wall has to tolerate, but as for the blanket itself, you have no "structural properties" to maintain, and cooling is only limited by the speed that you can cycle it.

The last paper I read on the subject also suggested that for breeding purposes one needs not only beryllium (they were reporting really poor results with high-Z multipliers), but the optimum ratio (to my surprise) worked out to be significantly more beryllium than lithium. So building structural elements out of beryllium serves double purpose, you don't have the excuse of "I need to use steel because it's cheaper" - you need the beryllium either way. It's strong, low density, similar melting point to steel, but retains strength better with heat, and highly thermally conductive. Beryllium swelling from helium accumulation stops at 750C+ as helium release occurs. So pairing a beryllium first wall with a FLiBe-based blanket seems like a very appropriate option.

Please don't get me wrong, I'm not at all disputing the great amount of engineering work left to do. I'm just more optimistic that appropriate solutions will be found. Perhaps I'm just naive in that regard ;)

Fast neutron cross scattering sections in the couple MeV range barely vary over more than the range of 1-10 barns

1-10 barns is, of course, by definition, an order of magnitude. There is a massive difference between 10 barns and 1 barn. Tenfold, to be precise. ;)

More to the point, you can't just combine all cross sections like that. The energy imparted from an elastic collision isn't the same as from an inelastic collsiion, which isn't the same as an (n, gamma), and so forth. Elastic collisions are particularly low energy, particularly the higher Z the target. Taking them out of the equation yields much greater differences between materials in the range of a couple MeV. The upper end of the neutron energies are "somewhat" similar (up to about one order of magnitude), but down below 6 or 7 MeV or so there's quite a few orders of magnitude difference.

Likewise, total cross sections have no bearing on the accumulation of impurities in the material. The particular cross sections are relevant not only in terms of reaction rate, but also what sort of impurities you tend to accumulate and what effect they have on the properties of the material. Which of course varies greatly depending on what exactly they are.

Integration of annealing cycles into blanket design is not brought up enough in some design studies, but is a consideration to help

It's not a side issue, it's a fundamental issue to the design of a material designed for high temperature operation under a high neutron flux.

Blanket design is extremely constrained by tritium breeder ratio to ensure more tritium is produced than used, which squeezes volume allowed to be used by coolant, ... but they have much lower neutron flux to worry about. Gen 4 reactor designs are in the 500-1000 C temperature range, exceeding in some cases what is thought reasonable for fusion blanket design. ... Blanket replacement is considerably more complex than fuel replacement in a fission reactor

Perhaps they've been heading in a different direction since I was last reading on the topic, but I was under the impression that a prime blanket material under consideration was FLiBe. Which operates in a temperature range of 459-1430C, and is its own coolant. That doesn't change what the first wall has to tolerate, but as for the blanket itself, you have no "structural properties" to maintain, and cooling is only limited by the speed that you can cycle it.

The last paper I read on the subject also suggested that for breeding purposes one needs not only beryllium (they were reporting really poor results with high-Z multipliers), but the optimum ratio (to my surprise) worked out to be significantly more beryllium than lithium. So building structural elements out of beryllium serves double purpose, you don't have the excuse of "I need to use steel because it's cheaper" - you need the beryllium either way. It's strong, low density, similar melting point to steel, but retains strength better with heat, and highly thermally conductive. Beryllium swelling from helium accumulation stops at 750C+ as helium release occurs. So pairing a beryllium first wall with a FLiBe-based blanket seems like a very appropriate option.

Please don't get me wrong, I'm not at all disputing the great amount of engineering work left to do. I'm just more optimistic that appropriate solutions will be found. Perhaps I'm just naive in that regard ;)

Fast neutron cross scattering sections in the couple MeV range barely vary over more than the range of 1-10 barns

1-10 barns is, of course, by definition, an order of magnitude. There is a massive difference between 10 barns and 1 barn. Tenfold, to be precise. ;)

More to the point, you can't just combine all cross sections like that. The energy imparted from an elastic collision isn't the same as from an inelastic collsiion, which isn't the same as an (n, gamma), and so forth. Elastic collisions are particularly low energy, particularly the higher Z the target. Taking them out of the equation yields much greater differences between materials in the range of a couple MeV. The upper end of the neutron energies are "somewhat" similar (up to about one order of magnitude), but down below 6 or 7 MeV or so there's quite a few orders of magnitude difference.

Likewise, total cross sections have no bearing on the accumulation of impurities in the material. The particular cross sections are relevant not only in terms of reaction rate, but also what sort of impurities you tend to accumulate and what effect they have on the properties of the material. Which of course varies greatly depending on what exactly they are.

Integration of annealing cycles into blanket design is not brought up enough in some design studies, but is a consideration to help

It's not a side issue, it's a fundamental issue to the design of a material designed for high temperature operation under a high neutron flux.

Blanket design is extremely constrained by tritium breeder ratio to ensure more tritium is produced than used, which squeezes volume allowed to be used by coolant, ... but they have much lower neutron flux to worry about. Gen 4 reactor designs are in the 500-1000 C temperature range, exceeding in some cases what is thought reasonable for fusion blanket design. ... Blanket replacement is considerably more complex than fuel replacement in a fission reactor

Perhaps they've been heading in a different direction since I was last reading on the topic, but I was under the impression that a prime blanket material under consideration was FLiBe. Which operates in a temperature range of 459-1430C, and is its own coolant. That doesn't change what the first wall has to tolerate, but as for the blanket itself, you have no "structural properties" to maintain, and cooling is only limited by the speed that you can cycle it.

The last paper I read on the subject also suggested that for breeding purposes one needs not only beryllium (they were reporting really poor results with high-Z multipliers), but the optimum ratio (to my surprise) worked out to be significantly more beryllium than lithium. So building structural elements out of beryllium serves double purpose, you don't have the excuse of "I need to use steel because it's cheaper" - you need the beryllium either way. It's strong, low density, similar melting point to steel, but retains strength better with heat, and highly thermally conductive. Beryllium swelling from helium accumulation stops at 750C+ as helium release occurs. So pairing a beryllium first wall with a FLiBe-based blanket seems like a very appropriate option.

Please don't get me wrong, I'm not at all disputing the great amount of engineering work left to do. I'm just more optimistic that appropriate solutions will be found. Perhaps I'm just naive in that regard ;)

The plasma facing material faces a flux of 1 neutron per 17,6Mev. By contrast, nuclear fuel cladding faces a flux of ~2,5 neutrons per 202,5 Mev, or 1 per 81 MeV. It's certainly higher, but it's not a whole different ballpark. And yes, you're dealing with higher energy neutrons but in a way that can help you - you've often got lower cross sections (for example), and in most cases you want the first wall to just let neutrons past.

There's a number of materials with acceptable properties. Graphite is fine (no wigner energy problems at those temperatures). Beryllium is great, and you need it anyway. In areas where the blanket isn't, boron carbide is great. Etc. These materials aren't perfect, but they're not things that get rapidly "converted into dust" by neutrons. Really, it's not the first wall in general anyway that I'd have concerns about, it's the divertor. The issue isn't so much that it takes a high neutron and alpha flux and "erodes" fast - that doesn't change the reactor's overall neutrons per unit power output ratio, and if you have a singular component that needs regular replacement, said replacement can be optimized. The issue is that you have to bear such an incredible thermal flux on one component. Generally you want to spread out thermal loads, it makes things a lot easier.

"Expanded solar-system limits on violations of the equivalence principle" James Overduin, Jack Mitcham and Zoey Warecki, Classical and Quantum Gravity, Volume 31, Number 1. IOP: http://m.iopscience.iop.org/ar... arxiv: http://arxiv.org/abs/1307.1202

"Four-Qubit Entanglement Classification from String Theory", L. Borsten, D. Dahanayake, M. J. Duff, A. Marrani, and W. Rubens
Physical Review Letters 105, 100507. APS: http://journals.aps.org/prl/ab... arxiv http://arxiv.org/abs/1005.4915

"Permutation orbifolds and holography", Felix M. Haehl, Mukund Rangamani Journal of High Energy Physics 2015:163 Springer: http://link.springer.com/artic... arxiv: http://arxiv.org/abs/1412.2759

"Quest for the Perfect Liquid: Connecting Heavy Ions, String Theory, and Cold Atoms" Barbara Jacak, John E. Thomas, Clifford Johnson, Symposium at tahe AAAS Amual Meeting 2009 https://www.bnl.gov/aaas09/per...

Yes and no. There is some advantage to getting close to real time data: there's a a Supernova Early Warning System http://snews.bnl.gov/. This isn't a safety issue, but rather an astronomy issue.

Detectors like IceCube can be used to actually detect the neutrinos from a supernova before the supernova's light reaches Earth. This isn't due to the erroneous claim from a few years ago that neutrinos travel faster than light, but rather because when a supernova occurs, the light from the core of the star takes multiple hours to get out of the core because of all the mass in the way, while the neutrinos aren't slowed down by this almost at all. This means that the neutrinos effectively get a few hours head start on the light- since they are traveling so close to the speed of light, they get to keep almost all this head start by the time they reach Earth. In the case of SN 1987A https://en.wikipedia.org/wiki/SN_1987A, a supernova in 1987 which was close enough that we could detect the flood of neutrinos, the neutrinos did as predicted arrive a few hours before the light. This means we can if we detect a neutrino burst and can get its directional data (which IceCube can approximately do) then we can point our telescopes at a supernova *before the light arrives at Earth* which means we'll get to see the very beginning of the supernova and hopefully get a much better understanding.

In order to do this you have to do at least some of your processing in at least close to real time as you can. This is especially important because it isn't actually easy to figure out from the neutrino burst what direction the supernova is coming from, and IceCube is one of the few detectors which gets any good directional data at all, so if this happens we want to process the data rapidly enough to get a good idea of where to look.

As of right now, the only confirmed neutrino sources we have that aren't artificial are the sun and SN 1987A https://en.wikipedia.org/wiki/SN_1987A. SN 1987A was a supernova in 1987 (the first one discovered that year, hence the A). The supernova was in the Large Magellanic Cloud, a very nearby galaxy (which is close enough and small enough that there's been some question whether we should really call it a separate galaxy). The supernova was one of the every few that was close enough that it was visible to earth by the naked eye. While every supernova is believed to create many neutrinos (and in fact this flood is an important part of the process) most supernovas are too far away for us to detect the neutrinos from the supernova because neutrinos are so hard to detect.

As of right now, we don't have any way of making any neutrino detector that is more sophisticated than putting a big bunch of mass in the way and hoping to notice when neutrinos happen to hit it by sheer chance (which is extremely rarely). IceCube is one of a next-generation detector where we have used pre-existing mass, in this case, ice as the South Pole for the bulk of the detector. It turns out that the ice very deep down under high pressure (from the ice above it) is nearly perfectly transparent at the light frequencies need, while the bulk of ice on top blocks out stray light and a lot of stray particles that would swamp the signal.

Detectors like IceCube can be used to actually detect the neutrinos from a supernova before the supernova's light reaches Earth. This isn't due to the erroneous claim from a few years ago that neutrinos travel faster than light, but rather because when a supernova occurs, the light from the core of the star takes multiple hours to get out of the core because of all the mass in the way, while the neutrinos aren't slowed down by this almost at all. This means that the neutrinos effectively get a few hours head start on the light- since they are traveling so close to the speed of light, they get to keep almost all this head start by the time they reach Earth. In the case of SN 1987A the neutrinos did as predicted arrive a few hours before the light. This means we can if we detect a neutrino burst and can get its directional data (which IceCube can approximately do) then we can point our telescopes at a supernova *before the light arrives at Earth* which means we'll get to see the very beginning of the supernova and hopefully get a much better understanding.

Right now, to assist in this there is a Supernova Early Warning System http://snews.bnl.gov/ which is tied in to the various big detectors so it can let astronomers know that a neutrino surge has been detected- this could of course be a supernova, but there's also the even more exciting possibility of an as yet unrecognized event that produces a lot of neutrinos. It will be very important in either case that a lot astronomers get a good early look at it, both professional and amateur, so the system is designed so that anyone can sign up for alerts from it. So if you are an amateur astronomer you should probably sign up- they send out about once test alert a year.

Contrats, of all of the many thousands of radioactive isotopes created by man or nature, you picked the one with the 32nd longest known half life. Try compared to nuclides in general.

There's a balance in terms of half life. The shorter the half life, the more intense the radiation - but the shorter you have to deal with the problem. The longer the half life, the less intense the radiation, but the longer you have to deal with the problem. The only way around this is a product that has a very low energy in its radioactive decay. And indeed, that's just what tritium is .

Tritium's decay energy is only 18.591 keV, which is tiny by the standards of radioactive decay - by comparison, U235's decay energy is 4678 keV - 251 times more intense. Furthermore, alpha radiation, while harmless outside the body (like tritium's ultra-weak beta), is (unlike beta) terrible inside it - its biological effectiveness is 20x that of beta. Hence a decay from a atom of U235 inside of you is 5032 times more damaging than a 18.591keV electron (beta). On top of this, you have biological half lives. Uranium's is only slightly longer than tritium's, 15 days instead of 12. But, again, U235 is not normally a problematic radioisotope. 239Pu, 90Sr, 226Ra, 45Ca, etc have biological half lives so long that they're effectively with you until they decay or you die. Oh, and on top of all of this? All of the energy of beta decay doesn't go into the electron; a higher percentage goes into the muon antineutrino, which escapes harmlessly off into space. The average energy of the beta particle from tritium decay is only 5.694 keV. Net result? Before controlling for the difference in half life, U235 is 20540 times worse for the body than tritium.

Now, of course, due to 235U's incredibly long half life, its radioactivity rarely a problem - which is why fresh fuel rods are not considered very dangerous, but spent ones are. People's concerns in nuclear accidents center around the fission products: strontium, iodine, plutonium, etc - things with shorter (but still problematically long) half lives and strong biological effectiveness. Versus them, the ridiculously low energy tritium is almost irrelevant in terms of biological effect, even if present in similar quantities. Combined with the very small amount of tritium that's in the torus at any point in time, it's just simply not even remotely comparable.

Did I even bother to mention that gaseous tritium tends to rapidly escape wherever it is and ascend up and out of the atmosphere? Tritium in the form of heavy water can be problematic in higher quantities, but of course, there's no "higher quantities" of any form of tritium in the torus.

So many more mistakes:

[ ... ]

As previously noted: the Tritium will remain cryogenically suspended, or it will "boil off". It's not an issue.

As for U-238: cadmium and Neodymium have the same level of "danger" as U-238, and are probably in your cell phone and the bluetooth headset you stick in your ear. They are closely followed by the following, to which you are generally exposed environmentally every day: xenon, molybdenum, barium, gadolinium, osmium, calcium, selenium, platinum, germanium, zirconium (quick, remove your rings!), tungsten, potassium, and bismuth.

http://www.nndc.bnl.gov/chart/

But you know, feel free to get all pedantic, and we can throw in charcoal briquettes, if you want. Imagine the environmental horror, if a train carrying a bunch of Brita water filters derailed, instead of, you know, getting to the store, and having all your drinking water go through them.

P.S.: Pedantry helps no one but alarmists, who want a technical detail hook on which to hang their argument.

catalyst for almost CO free process
this have achieved with Brookhaven National Laboratory

There are a number of studies that have examined the life cycle energy costs for photovoltaic panels. Start with this and go from there. Some numbers I've seen (like this) indicate the energy payback for monocrystalline PV modules is around two years; less for other technologies. Those numbers are from 2011, so I suspect that with increased manufacturing volume the numbers are even more favorable today.

A different argument that could be made comes down to basic economics. If solar panels took substantially more energy to manufacture than they produce over their lifespan, it would be reflected in their price. As the GP argued, albeit poorly, one can look at the price for a commodity and get from it a rough sense of the energy investment that it embodies. The wholesale price of PV modules is $1-2 per W of capacity, which one could argue represents tens of kWh of energy input. Even if there are externalities not captured in the price, and the total energy cost was hundreds of kWh per panel, that's still one or two orders of magnitude lower than the total lifetime output of the same panel.

U-235 and Pu-239 emit gamma particles in addition to the alpha particles, see page 20 of the Los Alamos Radiation Monitoring Notebook: http://www.nrrpt.org/file/Los%20Alamos%20Radiation%20Monitoring%20Notebook%202011.pdf or http://www.nndc.bnl.gov/chart/decaysearchdirect.jsp?nuc=239PU&unc=nds and http://www.nndc.bnl.gov/chart/decaysearchdirect.jsp?nuc=235U&unc=nds The gammas are lower energy, so they could be shielded easier than say, the gammas from Co-60, but a gamma detector would be able to detect sufficient quantities of U-235 and Pu-239.

U-235 and Pu-239 emit gamma particles in addition to the alpha particles, see page 20 of the Los Alamos Radiation Monitoring Notebook: http://www.nrrpt.org/file/Los%20Alamos%20Radiation%20Monitoring%20Notebook%202011.pdf or http://www.nndc.bnl.gov/chart/decaysearchdirect.jsp?nuc=239PU&unc=nds and http://www.nndc.bnl.gov/chart/decaysearchdirect.jsp?nuc=235U&unc=nds The gammas are lower energy, so they could be shielded easier than say, the gammas from Co-60, but a gamma detector would be able to detect sufficient quantities of U-235 and Pu-239.

There was a huge stink about this when the RHIC was brought on line (stranglets will eat Long Island !!!). This report covers the basics.

You can still see the characteristic and beautiful Cherenkov radiation at the research reactor at the University of Wisconsin-Madison. I've seen it a number of times.

Up until recently, it contained 1400 pounds of highly-enriched (weapons grade) U-235 in 58-pound bundles. It is in a building across from a 7-level parking ramp and an 80,000-person football stadium.

There are a number of such "Research and Test Reactors" around the US.

A 2005 ABC News report found:

- "No guards. No metal detectors. Bags were brought into the reactor room. Doors to the building are open during the day, and no IDs are required for entry."

- "The building was undergoing major renovation, and construction workers, large trucks and building materials surrounded the rear exterior."

- "The university Web site includes a 'virtual tour' and detailed photos, descriptions and diagrams of the reactor, the fuel elements and the control room. The reactor manager informed the Fellows that tours had to be scheduled three weeks in advance and that a locked door with a window view of the reactor was the closest they could get. But a friendly professor told the Fellows about a basement entry to the reactor room, where a reactor operator opened the door and let the Fellows photograph the reactor from the doorway. Two other operators allowed the Fellows to come inside carrying their tote bags, and briefly take photographs about 15 feet from the reactor's base. No campus security ever approached the Fellows."

An 2004 New York Times report found:

- "[UWNR's] fuel is weapons-grade uranium. If it were stolen, experts say, it could give terrorists or criminals a major head start on an atomic bomb."

- "[...] out of concern that the uranium might be turned into bomb fuel, the Department of Energy has spent millions of dollars to develop lower-grade fuel and convert scores of reactors to run on it. [...] But the six campus reactors in this country are not among them."

- "Campus reactors have far less security than places where the government keeps bomb-grade uranium, and they may have foreign students of unknown political sympathies."

- "[...] the fuel now in the campus reactors is dangerously radioactive, making it hard to handle. [...] however, that highly enriched uranium was an easier fuel from which to build a bomb than is plutonium."

- "The reactor operators are paid $10.50 an hour. They recently got a raise to that level [...] because someone discovered that campus file clerks were paid more than the reactor operators.

- "[...] the current fuel load will last about 108 years at current rates of use."

"The truck is the real threat. You want to make sure the truck stays away 250 feet minimum." - Ronald Timm, Former Department of Energy security analyst

Here, the primary entrance to a major parking ramp is about 50 feet away.

Also, it's not like it's really a mystery what he saw at BNL. There have only been so many reactors there in the last 60 years. It's odd, beautiful, and I suppose comparatively rare for a person to see, but it's not a big deal.

Not sure whether BMRR or HFBR were water-moderated, but I'd bet it was the Brookhaven Medical Research Reactor. A bunch of beautiful glowing stuff at the bottom of a deep pool of water is a common configuration for a research reactor used for the production of medical isotopes.

I won't even bother responding to the first remark considering how Slashdot has become. You know very well what I mean.

And you can claim what you want, I have had to work on designing photovoltaic devices myself on several occasions, hated every minute of it; I got so fed up with them that I quit my job.
So first of all, where did I say separately? It's simply a well known fact that semiconductor properties depend on environmental factors and those do include temperature, air pressure, humidity, ... Obviously temperature is the most important factor, and even that one is often left out of the equation when they do these sort of calculations. And GaAs does come into play when you want efficiency. All the multi-wavelength/junction designs are based on gallium-arsenide or germanium substrata as far as I'm aware of. You do have some variation in dopant materials but I fear I'd be going a bit off-topic with this.

I'll grant you that the first link does have some points. But I do not agree with their calculations.
This being the article they seem to get most of their data from: http://www.bnl.gov/pv/files/pdf/abs_193.pdf
The actual cost of manufacturing the substrata are very hard to define. Due to the increasing demand the solar panel industry has in fact started producing its own substrates as well. So the actual energy usage per square metre increased. The 14% efficiency as it should be around 10% for the panels they mention. The insolation values used are questionable. And I have yet to see an inverter last for more than 5 years without any sort of defect. Both the inverters I have owned always failed after roughly 4 years of service. The one I built myself (bit over designed mind you) is now up and running for 6 years and 2 months. Additionally their assumption about the main source of power is questionable as well as they modelled it based on the European power grid. Most solar panels are actually made in South-East Asia where dirty coal plants without air filters are still in common use. And the efficiency of the manufacturing process is also significantly lower due to older machines. This study on the other hand assumes machines of which some are still cutting edge at this point. Combine all these factors and I don't see it getting anywhere close to the 4 years they wish to claim. Last estimate I've seen that was trustworthy in my opinion was around 7 years on average assuming half of the panels were put at the equator and the other half put at the latitude of Berlin. It might have dropped a bit, but that study didn't really include the costs of the support equipment (mounting frames, inverters, modifications to the power grid for load balancing, ...).

The second link mainly seems to rehash what the first link said judging from the references at the bottom so not going to bother.
And we're talking about replacing the main power supply for the power grid. So yes, you will need a large amount of engineering. I doubt anybody has actually ever published a reliable article discussing the full environmental costs of dedicated solar plants.

From TFA:

The next step in the research will be to determine the remaining unknown quantity that is important to understanding the difference between matter and anti-matter in kaon decay. This last quantity will either confirm the present theory or perhaps, if they are lucky, Blum says, point to a new understanding of physics.

It appears that both theoretically and computationally there is still some work to be done.

Theoretically we have some more work to do, but computationally we have enough resources now that we have access to the IBM BlueGene/Q machines at BNL. The theory side of determining the other unknown quantity is no more complicated than the calculation detailed in the article, but there are a few technical challenges: first we have to figure out how to simulate the associated decay with physical kinematics (energy-momentum conservation) and secondly how we precisely calculate interactions involving decays of the pions into and out of the QCD vacuum. The second problem is essentially solved, and just requires a decent amount of computing power and some smart coding. We believe we also have a solution for the problem of obtaining physical kinematics, involving the use of unusual boundary conditions on the simulation, which is progressing rapidly.

The summary says that the device consumes hydrogen and nickel to produce copper by fusion (something that seems naively likely given their atomic numbers but a bit unlikely given their mass numbers, unless we're creating weird and radioactive isotopes here) but the article says that the nickel is just a catalyst over which the hydrogen passes.

According to table of nucleides,

http://www.nndc.bnl.gov/nudat2/reCenter.jsp?z=28&n=30&Zoom=1

Ni + p => Cu is a stupid reaction. Activation energy alone, never mind lack of energy production, is prohibitive. There will also be radioactive elements created unless he uses isotopic separation for Ni, which is very very unlikely.

To me this thing sounds like another scam.

The bigger problem is that Ni62 is the most tightly bound nucleus known, http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/nucbin2.html#c1 or http://www.nndc.bnl.gov/chart/ Fusion or fission of Ni62 require an input of energy; they clearly aren't measuring spontaneous release of energy in a fusion event...

The cluster you use doesn't have to be in the University the research group is housed in. Many clusters are available to researchers worldwide; you just upload your data/code to a processing queue and it gets run. You can remote-login to monitor the status, restart jobs, etc. You have quite a bit of control.

In fact, if the research in question is "high quality" and not proprietary then you can get access to various clusters for FREE. It's hard to beat free in terms of bang/buck. For instance, the US Department of Energy runs various computer clusters within "user facilities" (other funding agencies in US, Europe and elsewhere have similar programs). What this means is that you submit a proposal/request where you describe the research you're doing and what kind of resource you need (in this case, routine access to a computer cluster). If the proposal is highly rated (externally peer reviewed) then you're allocated access for free. In addition to getting access to the cluster itself, you get "access" to the experts who run the cluster--their expertise in optimizing and parallelizing code is extremely valuable.

I understand that having immediate access to computing power is useful. But if you're on a shoestring budget then something's gotta give, and using pre-existing clusters is a very efficient way to spend money. In the case of user clusters, if you can get free access then you can use a mixture of a smallish in-lab cluster and occasional access to the large-scale cluster. This is so easy to do (and did I mention free?), there's almost no reason not to try. (Yes, the DoE accepts proposals internationally, so there's no problem there.)

Disclosure: I work for the DoE, so I guess I'm biased. Here are some links that might help:
http://www.bnl.gov/cfn/facilities/Theory_and_Computation.asp
http://computing.ornl.gov/
http://www.alcf.anl.gov/

Yes, yes, today's neutrino detectors are larger than the ones operating in 1987. However, I don't think they could make up this sort of difference.

Correct, it's a simple matter of 1/r^2 geometry. SN1987A was at 51.4 kpc. M101 is at 6.5 Mpc. So even if this was a core-collapse supernova (which it's not), we would see only 62-millionths of the signal as we did in 1987. Our detectors are bigger, but only 50 times bigger. We're still three orders of magnitude away from seeing this one with neutrinos.

Even a neutrino producing SN in the next big galaxy neighbor we have (M31 in Andromeda) would only give us about one neutrino event in our biggest detector (Super-K), which likely would go unnoticed. On the other hand, pretty much anything in our own galaxy or its small satellites will produce a huge signal. Space is a big, empty place.

And if you're curious and eager to learn about that once-a-century event before your slightly less-geeky buddies, check out the Supernova Early Warning System, sign up to get an email when we see neutrinos from a "nearby" supernova. Just don't hold your breath while waiting.

This is close enough that you can see it with a good amateur telescope. The supernova will brighten over time, probably hitting its brightest point sometime in the middle of September. As it brightens it might even be possible to see it with a cheap telescope or a pair of binoculars.

One thing that is important to realize is that this supernova is Type Ia, not Type II. Type II supernovae are what most people are thinking of when they think of a supernova (that is, death of a massive star). A Type Ia supernova instead occurs in a binary system where one of the stars is a white dwarf. The white dwarf slowly steals away mass from the other star until the white dwarf gets too big to be stable, around 1.4 times the mass of the sun. Then it experiences collapse in a way that is essentially similar to that of the Type II supernova.

This supernova was very close to us. One thing that could be very promising is if this left any neutrino signature above the background level. Neutrinos are very hard to detect, the major detectors are things like IceCube http://en.wikipedia.org/wiki/IceCube_Neutrino_Observatory or Super-K http://en.wikipedia.org/wiki/Super-Kamiokande which have very large containers of water or some other substance and you then carefully try to detect the very rare neutrino interactions over all the background radiation (neutrinos are very ghostly and don't interact very much. You have billions of them going through you all the time and you don't even notice). This has only happened with one supernova before SN 1987A http://en.wikipedia.org/wiki/SN_1987A which was bright enough and close enough to be seen by the naked eye. One really cool thing about this was that we actually recorded the neutrino burst for SN 1987A before the light arrived (three hours before). At this point, most people get shocked because they know that nothing travels faster than the speed of light. What happened was that in a Type II supernova neutrino burst occurs at the very beginning of the supernova process, but the light has to work its way out of the whole star. This actually allows us to potentially detect supernova before they happen, and there's now an early warning network with the major neutrino detectors so astronomers can get a heads-up if a type II is about to happen so they know where to point the telescopes. http://snews.bnl.gov/ Since the neutrino flux drops off quickly (like 1/r^2), supernovae need to be very close to us for to be able to pick out the neutrinos over all the solar neutrinos and general background junk. I don't fully understand the dynamics of Type Ia supernova (and I'm not an astronomer or an astrophysicist) but my impression is that there's also reason to believe that type Ia will produce fewer neutrinos than a Type II supernova. Between that and the distance, this supernova was probably too far away for us to detect any neutrinos.I suspect that the people who run the major detectors are probably looking over their data for the last few days very carefully to see if they can pick up any signal that the regular automated systems missed.

Potassium 40 is a beta emitter. Buy some kg of a potassium compound (KCl, KNO3, etc. Plenty of fertilizers are made up of potassium salts), estimate the total amount of K present in your sample, and from this chart you can easily estimate the total activity of your sample. If you are lazy, the 0.0117% of your potassium is radioactive. Estimating the amount of radiations emitted in a second and how to estimate the expected number of counts hitting your Geiger detector is a trivial exercise, that you should be capable of performing, since you want to succesfully calibrate and use a Geiger counter.

According to http://www.nndc.bnl.gov/chart/reCenter.jsp?z=24&n=24, Cr-48 is is radioactive, with a half life of about 21.5 hrs.
It decays by inverse beta decay (electron capture) which is funny since Google applications seem to stay in beta forever.

Cobalt-76 ? really? It seems to me that they should publish this in a peer-reviewed journal as it seems they have found a new Isotope.
At least according to these two nuclid charts cobalt-76 is unknown.

To be fair, "high-temperature" in the context of superconductors usually means "you can cool them with liquid nitrogen". Room-temperature superconductors are the goal, but we're not there yet. Still, nitrogen is cheap enough that current superconductors can be (and already are) used for transmission lines.

If we could find a means of mass-producing the current highest-temperature superconductor, HBCCO, we'd be pretty well set as it needs less cooling and (with the exception of a small amount of mercury) uses elements that are already mined in vast quantities.

all the Candian jokes are nice and all.. but this really was about trying to make people think CERN is the only thing going on in HEP or nuclear physics. Not so, and this is not a first as RHIC was there first. Glad to see CERN is catching up though.

I thought the big deal with the LHC is that it was supposed to give us the Higgs Boson, as no other collider on earth was powerful enough to create the Higgs. Enough about this QGP junk. Where's our Higgs Boson?

all the Candian jokes are nice and all.. but this really was about trying to make people think CERN is the only thing going on in HEP or nuclear physics. Not so, and this is not a first as RHIC was there first. Glad to see CERN is catching up though.

Hooray! LHC has "discovered" "hints" of what the experiments at RHIC found several years ago...

So far all the elements produced near the island of stability are isotopes with a fewer neutrons than would be needed for them to have long lifetimes. It is still too early to know how long these super heavy elements will last. Yet, there have been several produced in the 112+ range with half-lifes on the order of minutes.

Just explore the top of the chart at nndc to see.

Just released yesterday I think. Some cool new stuff discovered at the rhic at brookhaven national labs. http://www.bnl.gov/bnlweb/pubaf/pr/PR_display.asp?prID=1074 "“This research offers significant insight into the fundamental structure of matter and the early universe, highlighting the merits of long-term investment in large-scale, basic research programs at our national laboratories,” said Dr. William F. Brinkman, Director of the DOE Office of Science. “I commend the careful approach RHIC scientists have used to gather detailed evidence for their claim of creating a truly remarkable new form of matter.”"

How long they are 'guaranteed' for is completely and utterly irrelevant. In the first place, trusting in that means trusting the company offering the guarantee will be around and will honor it, and in the second place that the owner will remember to invoke the 'guarantee' and obtain replacements.

If people don't stand up for thenselves nothing is relevant, people usually have to stand up for themselves, no matter what it's over. This is no different. People need to investigate installers and the products they use if they are not specified. Plenty of people have built off the grid and share information and their experiences. There are a number of publications, magazines, touching on various things these people do or are interested in. I've personally been reading magazines like Homepower, Backwoods Home, and Solar Today for 10 or 20 years if not more.

Even if the 'guarantee' exists, and is honored, that still doesn't change what I said. Panels that need replacement for whatever reason mean new panels need to be manufactured.

This doesn't change the fact that old panels can be recycled and that new one have better efficiency so less are needed to supply the same amount of power if not more.

Learn to think, rather than parroting.

I suggest you do the same, PV Panel Disposal and Recycling, The Value and Feasibility of Proactive Recycling.

Falcon

I read about how coal could be converted to methane via bacteria.

here's a quick example.

http://www.bnl.gov/bnlweb/pubaf/pr/2003/bnlpr091103b.htm

This is one way to convert coal to a cleaner form of energy. However there are implications since there is a question as to who owns the energy: coal companies or gas companies?

So to create cleaner coal we just may need to pump some bugs and other chemicals into the ground but we also need to sort out some legal and policy issues.

OK, somebody pucker up and tell me why BNL is not a particle physics laboratory. How many others are there really?

Brookhaven received a donation $13 million so that the 2006 RHIC run could go for 20 weeks, vs 12. (The summary to the contrary, I would say that BNL is a particle physics lab.)

http://www.bnl.gov/bnlweb/pubaf/pr/PR_display.asp?prID=06-X2
http://www.math.columbia.edu/~woit/wordpress/?p=328

This year though, the budget process is such that there may not be a RHIC run at all!

Well... I am one of DOE's "gatekeepers", so perhaps I can shed some light on the nature of the red tape. Actually, I am a proposal reviewer for the Advanced Photon Source and for the National Synchrotron Light Source, the x-ray facilities next door to two DOEs nanoscience facilities. So I help mind the gates for the x-ray facilities, not the nanoscience facilities, which are the topic of this article. But the process for access to the nanoscience facilities is very similar to our process.

First, we are not a secret cabal. The names of the proposal review panel members are listed on the web sites for the two x-ray facilities for which I do this work. (For the sake of transparency, I am Bruce Ravel on the Spectroscopy panel at the APS - http://www.aps.anl.gov/About/Committees/Proposal_Review_Panel/ - and the
X-Ray Spectroscopy: Chemical and Material Sciences panel at NSLS - http://www.nsls.bnl.gov/organization/committees/prp.htm.) Reviews are signed by the panel as a whole, not by individuals, but you know who we are.

Second, the procedure is not a mystery. There is a standardized form that the proposer must fill out. We review the contents of that form to assure that the experiment proposed is feaasible in the sense that it is well-conceived and appropriate to the instrment requested.

Third, the demand for these resources is high. At the APS, virtually every instrument receives more requests for time that there are days in the operating calendar. It is inevitable that some folks will come away disappointed. I cannot speak for all of my fello reviewers, but I write (what I hope are) useful comments in every review to help the proposer write a stringer, more competitive proposal the next time. One of the comment farther down is from someone who failed to get timefor an experiment at the APS. My advice to him or her is to contact the beamline scientist at the beamline and/or the user office and ask for advice about how to make your proposal sringer next time.

Fourth, although the process is challenging in the sense that not every proposal is going to result in access, the resources being offered are quite extraordinary. A researcher from academia or a national lab gets free access to the instrument with no obligation to cover the operating costs of the facility or of the special equipment available at the specific instrument. Companies get the same benefit for non-proprietary work. (Proprietary work involves cost-recovery, but many corporations choose to publish much of their work.) Except for the proprietary work, all users are expected to publish in peer-reviewed, widely available journals.

Fifth, everyone enters pretty equally. I get good proposals from institutions of all sizes and poor proposals from the same mix of institutions. One of colleagues and a very fine practioner of my specialty is faculty at Sarah Lawrence College -- certainly not a huge unversity -- and he has quite adequate access to DOEs facilities.

My comments are, of course, specifically relvant to the x-ray facilities. But similar models are used for the nanocenters.

So, yes... there is red tape, but there has to be. There is far more demand than supply. There are safety issues that range from the mundane to the severe. Adn there are obligations both for the facility and for the user to perform and report science of the highest quality.

I interact with users of the DOE facilities on a daily basis. I think the system is highly succesful (although not without warts and blemishes) and so do the vast majority of the people I see every day.

I'm a physicist in grad school, so maybe my cross section of mac users is entirely from a different demographic.

Maybe you should use a standardized cross-section library like ENDF.

I'm not sure when they added it; I was first there two summers ago but I can ask the other people in my group. It's called the "Center", and is across the street from the water tower and police station.

http://www.bnl.gov/visitorinfo/onsite_services.asp#center

Oh, and an article could quite easily meet my (not exceptionally high) quality standards: http://www.bnl.gov/bnlweb/pubaf/pr/PR_display.asp?prID=08-x5.

Rather than "they used a supercomputer to do physics"

http://www.bnl.gov/bnlweb/pubaf/pr/PR_display.asp?prID=08-x5