5 ms·

ISTR something about that from a few years ago, and thinking about the eventual possibility about triangulating nuclear subs and carriers with a network of such

ISTR something about that from a few years ago, and thinking about the eventual possibility about triangulating nuclear subs and carriers with a network of such 'sensors'. Through the whole earth, maybe. In real-time. Wouldn't that be something?

firstlink 4y ago
It would indeed be something. Neutrino-based sensors are seen sometimes in hard science fiction. I always assumed that was a little implausible because of the compounding problem of neutrinos interacting poorly with the target and with the sensor. But here we are, a stone's throw from making such sensors a reality, albeit looking for sources rather than shadows.
- PaulHoule 4y ago
  This turns up in Vernor Vinge's https://en.wikipedia.org/wiki/The_Peace_War https://en.wikipedia.org/wiki/The_Peace_War
- dragonwriter 4y ago
  We’ve had neutrino sensors for a half century. They just tend to be inconveniently sized and located.
bumby 4y ago
By any chance, do you have any suggestions for further reading on this topic?
- LargoLasskhyfv 4y ago
  Not exactly. I can't even remember where I've read that. Most probably on some (pop-)science aggregator like phys.org, or similar. About a few times, popping up again several years later. Then somewhere else on some blogs, maybe even scmp.com
- snophysics 4y ago
  They aren't really doing directionality, but the WATCHMAN collaboration (https://svoboda.ucdavis.edu/experiments/watchman https://svoboda.ucdavis.edu/experiments/watchman) is developing detectors like this for nuclear non-proliferation.
lapetitejort 4y ago
Governments can easily guard against this by encasing their nuclear subs in a 11 trillion km diameter lead sphere.
- treeman79 4y ago
  Trick is getting it to stay a 11 trillion km sphere. Has a habit of turning into a black hole.
  - deleted 4y ago
    [deleted]
  - the_third_wave 4y ago
    As long as the neutrinos are not too energetic they'd be contained by the black hole as well so what's the problem? To put it bluntly such a transformation would even negate the necessity to have nuclear submarines - or anything else for that matter - in the first place so that black hole would save a lot of money and effort as well.
    - AnimalMuppet 4y ago
      Building an 11 million km sphere of lead is not the path to "save a lot of money and effort".
      - twic 4y ago
        Exactly. The way naval procurement works, it'd be a 15 million km sphere before construction even started.
- matthewdgreen 4y ago
  More seriously I assume there’s a team at a US National Laboratory working out the parameters for building such a sensor, and (if they’re even remotely practical) another team figuring out how many false sources would be needed to hopelessly confuse it.
- 4y ago
openasocket 4y ago
To do that you would need the sensor to provide either the distance or direction of the “signal,” right? Does this actually do that? Given how unreactive neutrinos are I can’t imagine there being much decay or defraction or distortion over distance. Can this experimental sensor produce a direction that the neutrinos are coming from?
- dragonwriter 4y ago
  > To do that you would need the sensor to provide either the distance or direction of the “signal,” right? It was specifically called out that one of the things this relied on is that their detector method provides an estimated direction. OTOH, when you have to integrate a half year of data to detect any signal, triangulation of non-stationary sources, especially if there is more than one potential source, is going to be…beyond difficult.
  - jjk166 4y ago
    You can integrate the same amount of data in less time by increasing the size of the detector. With a detector 182.5 times greater in volume (which is only 6 times the radius), you only need a day's worth of data - still probably not useful for targeting but now you know the search area to look within. You can also build a network of multiple detectors, which in addition to increasing the amount of data you collect also makes it easier to differentiate signals. For a nation state this would be chump change.
    - dragonwriter 4y ago
      > With a detector 182.5 times greater in volume (which is only 6 times the radius), you only need a day’s worth of data Oh, okay, so you just want to scale this up ~200 times, and build multiple of them (deep underground, because the water is shielding for the ambient radiation from the rock, which it has a couple km of shielding it from external radiation): “The heart of the SNO+ detector is a 12m diameter acrylic sphere filled with 780 tonnes of liquid scintillator that is surrounded by 7000 tonnes of ultrapure water which serves as shielding from external ambient radioactivity. This volume is monitored by nearly 10,000 photomultiplier tubes (PMTs) that are very sensitive light detectors.” [0] > You can also build a network of multiple detectors Well, yes, you can’t triangulate with only one detector, you have to do that at a minimum. That’s not an “also you can” option, its a minimum requirement because you need multiple simultaneous (or close enough) signals from the same source to triangulate. [0] https://snoplus.phy.queensu.ca/about.html https://snoplus.phy.queensu.ca/about.html

firstlink 4y ago

It would indeed be something. Neutrino-based sensors are seen sometimes in hard science fiction. I always assumed that was a little implausible because of the compounding problem of neutrinos interacting poorly with the target and with the sensor. But here we are, a stone's throw from making such sensors a reality, albeit looking for sources rather than shadows.

PaulHoule 4y ago
This turns up in Vernor Vinge's https://en.wikipedia.org/wiki/The_Peace_War https://en.wikipedia.org/wiki/The_Peace_War
dragonwriter 4y ago
We’ve had neutrino sensors for a half century. They just tend to be inconveniently sized and located.

bumby 4y ago

By any chance, do you have any suggestions for further reading on this topic?

LargoLasskhyfv 4y ago
Not exactly. I can't even remember where I've read that. Most probably on some (pop-)science aggregator like phys.org, or similar. About a few times, popping up again several years later. Then somewhere else on some blogs, maybe even scmp.com
snophysics 4y ago
They aren't really doing directionality, but the WATCHMAN collaboration (https://svoboda.ucdavis.edu/experiments/watchman https://svoboda.ucdavis.edu/experiments/watchman) is developing detectors like this for nuclear non-proliferation.

lapetitejort 4y ago

Governments can easily guard against this by encasing their nuclear subs in a 11 trillion km diameter lead sphere.

treeman79 4y ago
Trick is getting it to stay a 11 trillion km sphere. Has a habit of turning into a black hole.
- deleted 4y ago
  [deleted]
- the_third_wave 4y ago
  As long as the neutrinos are not too energetic they'd be contained by the black hole as well so what's the problem? To put it bluntly such a transformation would even negate the necessity to have nuclear submarines - or anything else for that matter - in the first place so that black hole would save a lot of money and effort as well.
  - AnimalMuppet 4y ago
    Building an 11 million km sphere of lead is not the path to "save a lot of money and effort".
    - twic 4y ago
      Exactly. The way naval procurement works, it'd be a 15 million km sphere before construction even started.
matthewdgreen 4y ago
More seriously I assume there’s a team at a US National Laboratory working out the parameters for building such a sensor, and (if they’re even remotely practical) another team figuring out how many false sources would be needed to hopelessly confuse it.
4y ago

openasocket 4y ago

To do that you would need the sensor to provide either the distance or direction of the “signal,” right? Does this actually do that? Given how unreactive neutrinos are I can’t imagine there being much decay or defraction or distortion over distance. Can this experimental sensor produce a direction that the neutrinos are coming from?

dragonwriter 4y ago
> To do that you would need the sensor to provide either the distance or direction of the “signal,” right? It was specifically called out that one of the things this relied on is that their detector method provides an estimated direction. OTOH, when you have to integrate a half year of data to detect any signal, triangulation of non-stationary sources, especially if there is more than one potential source, is going to be…beyond difficult.
- jjk166 4y ago
  You can integrate the same amount of data in less time by increasing the size of the detector. With a detector 182.5 times greater in volume (which is only 6 times the radius), you only need a day's worth of data - still probably not useful for targeting but now you know the search area to look within. You can also build a network of multiple detectors, which in addition to increasing the amount of data you collect also makes it easier to differentiate signals. For a nation state this would be chump change.
  - dragonwriter 4y ago
    > With a detector 182.5 times greater in volume (which is only 6 times the radius), you only need a day’s worth of data Oh, okay, so you just want to scale this up ~200 times, and build multiple of them (deep underground, because the water is shielding for the ambient radiation from the rock, which it has a couple km of shielding it from external radiation): “The heart of the SNO+ detector is a 12m diameter acrylic sphere filled with 780 tonnes of liquid scintillator that is surrounded by 7000 tonnes of ultrapure water which serves as shielding from external ambient radioactivity. This volume is monitored by nearly 10,000 photomultiplier tubes (PMTs) that are very sensitive light detectors.” [0] > You can also build a network of multiple detectors Well, yes, you can’t triangulate with only one detector, you have to do that at a minimum. That’s not an “also you can” option, its a minimum requirement because you need multiple simultaneous (or close enough) signals from the same source to triangulate. [0] https://snoplus.phy.queensu.ca/about.html https://snoplus.phy.queensu.ca/about.html