5 ms·

I don't want to hate on this research but my first thought was "well duh of course you COULD but why WOULD you?" This is basically just Morse code with a neutro

by gh02t 5y ago

I don't want to hate on this research but my first thought was "well duh of course you COULD but why WOULD you?" This is basically just Morse code with a neutron source. That this is possible is obvious to anybody with a passing familiarity with nuclear engineering, but equally clear is the lengthy list of downsides. Just because nobody has done it doesn't make it novel. This is no doubt meant as a proof of concept and an electronically controlled neutron generator would solve some of the problems, but I still can't think of any use for this that isn't better solved some other way.

bnegreve 5y ago
> I still can't think of any use for this that isn't better solved some other way. What about this? "In some safety-critical scenarios, such as concerning the integrity of reactor containments, and metal vaults and bulkheads in maritime structures, it can be important to minimise the number of penetrations made through such metal structures for communications cabling. The use of neutrons for information transmission through such structures could negate the need for such penetrations and is perhaps also relevant to scenarios where limited transmissions are desirable in difficult circumstances, such as for emergency rescue operations."
- cycomanic 5y ago
  Well what about mechanical waves /sound waves. I mean we are talking about rates of less than a bit per second. Just have a small hammer ping your metal container. Will go much further is much cheaper and can easily do a higher data rate.
  - toast0 5y ago
    You can probably do something with optical communications through a thick, leaded glass window, depending on your containment needs.
  - titanomachy 5y ago
    More moving parts than an electrically-modulated neutron source. But this was my first thought as well.
    - lazide 5y ago
      Piezoelectrics?
    - gh02t 5y ago
      Acoustic was also my first thought. Neutron generators are quite complicated and relatively delicate. Meanwhile acoustic transducers (e.g. piezo) are super simple and low power.
    - R0b0t1 5y ago
      Piezoelements would work well. Not really a moving part in the traditional sense, with worn surfaces from friction.
    - andi999 5y ago
      The danger zone for humans is smaller though.
  - andylynch 5y ago
    The ‘safety critical maritime structures’ they are talking about are probably pressure hulls on nuclear submarines. They are well equipped to handle radiological material and really want to be quiet.
- smartscience 5y ago
  That's still more than a bit of a stretch considering the drawbacks, such as making that vault or bulkhead material radioactive even after the neutron beam has been shut off. In practice the duraction of the induced radioactivity varies considerably depending on the material; just hope it's not an alloy that includes cobalt.
- gh02t 5y ago
  Yeah I read that, but it's not going to be good for that. For one thing that isn't going to work in a nuclear reactor core because the neutron background is orders of magnitude higher than any neutron generator could hope to produce. For the other uses they mentioned... I mean like I said there's no reason it wouldn't work (over short ranges) but there are simpler solutions that don't involve [very dangerous] neutron radiation. Plus a neutron generator requires a decent bit of power to run (they're basically a compact particle accelerator) so you're back to needing a vessel penetration. And the idea that such a device would be useful for emergency rescue operations is frankly silly.
14 5y ago
I know nothing about nuclear energy but I immediately thought about the Tokamak. The article said it could be useful for scenarios where penetration of a wall of a device would be problematic. I thought I wonder if the Tokamak had the need to be sealed in some way and being able to send a signal inside it wirelessly would help. Maybe they need a completely sealed room but they also need to trigger a switch but no one can be in the room and typical communication can not penetrate it. You just need one bit to make it through to flip that switch from a 1 to a 0. This would be the perfect device. Ya I know that probably has no use for the Tokamak and I can’t think of a scenario where you need a completely sealed device with no holes but still need to send a signal inside. Like in the article they also mentioned submarine communications. You sound smart but surely if they could just do other forms of communication they would have already the US military budget is massive. Currently subs float a device to the surface so they can talk. The article says this slows them down and risks exposing them. Beside the couple mentioned in the article already I’m sure there has to be more use cases someone smarter then your or I can see.
- gh02t 5y ago
  Neutron transmission is not useful in any of these scenarios. Not in a fusion reactor because a fusion reactor produces a ton of neutrons itself, many orders of magnitude higher than any transmission you'd be able to make so it'd be drowned out (most neutron generators use fusion to produce neutrons too so they're probably also at similar energies to what the reactor makes). Plus the problem with the inside of a tokamak vessel is that it's a super extreme environment and not much can survive in there and like I said in another comment you still have to power your neutron generator. Neutrons are also relatively short ranged and more-or-less isotropic in emission (not able to be focused effectively), meaning you need really high fluence (=dangerous) to transmit more than a few meters. For submarines, water actually attenuates neutrons extremely quickly making it completely useless there. And also let's not forget that neutrons activate materials and make them radioactive for long periods even after you stop with the neutrons. For totally sealed rooms there are better solutions (e.g an acoustic transducer). On top of all this, the physics of neutrons mean this will always be very low bandwidth. None of the applications mentioned in the article are remotely credible, IMO, and this is my area of expertise. Perhaps there is some application where this is the best solution. My point is that at best it's extremely niche; the article makes it out like this is revolutionary but it is definitely not nor is it even particularly interesting. This is not military research with an intended application, this is someone slowly moving a block of plastic back and forth in front of a californium source in a university lab and a press release declaring victory. The actual article published by the scientists in NIM is much more reasonable, but the one linked here is greatly playing up the utility. A fairly reasonable analogy that captures some of the downsides of using neutrons for this is that you could also transmit information by shooting at a metal plate with a pellet gun and having someone listen for the pinging sound. Sure it's possible, but the list of drawbacks is pretty long.
hasmanean 5y ago
Next step: move from CW(code word) to CDMA. Hedy Lamar owns the patent on CDMA with punch cards but you could own the neutron patent.
- gh02t 5y ago
  CW is "continuous waveform" not "code word" at least in the context of radio and is probably the only way this can work. You can't really modulate neutron energy/frequency with any sort of fine control, so most of the fancy techniques with radio waves are out. CDMA is sorta possible, but bandwidth is always gonna be low.

by gh02t 5y ago

bnegreve 5y ago

> I still can't think of any use for this that isn't better solved some other way. What about this? "In some safety-critical scenarios, such as concerning the integrity of reactor containments, and metal vaults and bulkheads in maritime structures, it can be important to minimise the number of penetrations made through such metal structures for communications cabling. The use of neutrons for information transmission through such structures could negate the need for such penetrations and is perhaps also relevant to scenarios where limited transmissions are desirable in difficult circumstances, such as for emergency rescue operations."

cycomanic 5y ago
Well what about mechanical waves /sound waves. I mean we are talking about rates of less than a bit per second. Just have a small hammer ping your metal container. Will go much further is much cheaper and can easily do a higher data rate.
- toast0 5y ago
  You can probably do something with optical communications through a thick, leaded glass window, depending on your containment needs.
- titanomachy 5y ago
  More moving parts than an electrically-modulated neutron source. But this was my first thought as well.
  - lazide 5y ago
    Piezoelectrics?
  - gh02t 5y ago
    Acoustic was also my first thought. Neutron generators are quite complicated and relatively delicate. Meanwhile acoustic transducers (e.g. piezo) are super simple and low power.
  - R0b0t1 5y ago
    Piezoelements would work well. Not really a moving part in the traditional sense, with worn surfaces from friction.
  - andi999 5y ago
    The danger zone for humans is smaller though.
- andylynch 5y ago
  The ‘safety critical maritime structures’ they are talking about are probably pressure hulls on nuclear submarines. They are well equipped to handle radiological material and really want to be quiet.
smartscience 5y ago
That's still more than a bit of a stretch considering the drawbacks, such as making that vault or bulkhead material radioactive even after the neutron beam has been shut off. In practice the duraction of the induced radioactivity varies considerably depending on the material; just hope it's not an alloy that includes cobalt.
gh02t 5y ago
Yeah I read that, but it's not going to be good for that. For one thing that isn't going to work in a nuclear reactor core because the neutron background is orders of magnitude higher than any neutron generator could hope to produce. For the other uses they mentioned... I mean like I said there's no reason it wouldn't work (over short ranges) but there are simpler solutions that don't involve [very dangerous] neutron radiation. Plus a neutron generator requires a decent bit of power to run (they're basically a compact particle accelerator) so you're back to needing a vessel penetration. And the idea that such a device would be useful for emergency rescue operations is frankly silly.

14 5y ago

I know nothing about nuclear energy but I immediately thought about the Tokamak. The article said it could be useful for scenarios where penetration of a wall of a device would be problematic. I thought I wonder if the Tokamak had the need to be sealed in some way and being able to send a signal inside it wirelessly would help. Maybe they need a completely sealed room but they also need to trigger a switch but no one can be in the room and typical communication can not penetrate it. You just need one bit to make it through to flip that switch from a 1 to a 0. This would be the perfect device. Ya I know that probably has no use for the Tokamak and I can’t think of a scenario where you need a completely sealed device with no holes but still need to send a signal inside. Like in the article they also mentioned submarine communications. You sound smart but surely if they could just do other forms of communication they would have already the US military budget is massive. Currently subs float a device to the surface so they can talk. The article says this slows them down and risks exposing them. Beside the couple mentioned in the article already I’m sure there has to be more use cases someone smarter then your or I can see.

gh02t 5y ago
Neutron transmission is not useful in any of these scenarios. Not in a fusion reactor because a fusion reactor produces a ton of neutrons itself, many orders of magnitude higher than any transmission you'd be able to make so it'd be drowned out (most neutron generators use fusion to produce neutrons too so they're probably also at similar energies to what the reactor makes). Plus the problem with the inside of a tokamak vessel is that it's a super extreme environment and not much can survive in there and like I said in another comment you still have to power your neutron generator. Neutrons are also relatively short ranged and more-or-less isotropic in emission (not able to be focused effectively), meaning you need really high fluence (=dangerous) to transmit more than a few meters. For submarines, water actually attenuates neutrons extremely quickly making it completely useless there. And also let's not forget that neutrons activate materials and make them radioactive for long periods even after you stop with the neutrons. For totally sealed rooms there are better solutions (e.g an acoustic transducer). On top of all this, the physics of neutrons mean this will always be very low bandwidth. None of the applications mentioned in the article are remotely credible, IMO, and this is my area of expertise. Perhaps there is some application where this is the best solution. My point is that at best it's extremely niche; the article makes it out like this is revolutionary but it is definitely not nor is it even particularly interesting. This is not military research with an intended application, this is someone slowly moving a block of plastic back and forth in front of a californium source in a university lab and a press release declaring victory. The actual article published by the scientists in NIM is much more reasonable, but the one linked here is greatly playing up the utility. A fairly reasonable analogy that captures some of the downsides of using neutrons for this is that you could also transmit information by shooting at a metal plate with a pellet gun and having someone listen for the pinging sound. Sure it's possible, but the list of drawbacks is pretty long.

hasmanean 5y ago

Next step: move from CW(code word) to CDMA. Hedy Lamar owns the patent on CDMA with punch cards but you could own the neutron patent.

gh02t 5y ago
CW is "continuous waveform" not "code word" at least in the context of radio and is probably the only way this can work. You can't really modulate neutron energy/frequency with any sort of fine control, so most of the fancy techniques with radio waves are out. CDMA is sorta possible, but bandwidth is always gonna be low.